Class: OpenStudio::Model::AirLoopHVAC

Inherits:
Object
  • Object
show all
Defined in:
lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb,
lib/openstudio-standards/hvac_sizing/Siz.AirLoopHVAC.rb

Overview

Reopen the OpenStudio class to add methods to apply standards to this object

Instance Method Summary collapse

Instance Method Details

#add_motorized_oa_damper(min_occ_pct = 0.15, occ_sch = nil) ⇒ Bool

Add a motorized damper by modifying the OA schedule to require zero OA during unoccupied hours. This means that even during morning warmup or nightcyling, no OA will be brought into the building, lowering heating/cooling load. If no occupancy schedule is supplied, one will be created. In this case, occupied is defined as the total percent occupancy for the loop for all zones served.

the system will be considered unoccupied. If not supplied, one will be created based on the supplied occupancy threshold.

Parameters:

  • min_occ_pct (Double) (defaults to: 0.15) —

    the fractional value below which

  • occ_sch (OpenStudio::Model::Schedule) (defaults to: nil) —

    the occupancy schedule.

Returns:

  • (Bool) —

    true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2765

def add_motorized_oa_damper(min_occ_pct = 0.15, occ_sch = nil)
  # Get the airloop occupancy schedule if none supplied
  if occ_sch.nil?
    occ_sch = get_occupancy_schedule(min_occ_pct)
    flh = occ_sch.annual_equivalent_full_load_hrs
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Annual occupied hours = #{flh.round} hr/yr, assuming a #{min_occ_pct} occupancy threshold.  This schedule will be used to close OA damper during unoccupied hours.")
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Setting motorized OA damper schedule to #{occ_sch.name}.")
  end

  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir

  # Set the minimum OA schedule to follow occupancy
  oa_control.setMinimumOutdoorAirSchedule(occ_sch)

  return true
end

#adjust_minimum_vav_damper_positions ⇒ Bool

TODO:

Add exception logic for systems serving parking garage, warehouse, or multifamily

Adjust minimum VAV damper positions to the values

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2021

def adjust_minimum_vav_damper_positions
  # Total uncorrected outdoor airflow rate
  v_ou = 0.0
  thermalZones.each do |zone|
    v_ou += zone.outdoor_airflow_rate
  end

  v_ou_cfm = OpenStudio.convert(v_ou, 'm^3/s', 'cfm').get

  # System primary airflow rate (whether autosized or hard-sized)
  v_ps = 0.0

  v_ps = if autosizedDesignSupplyAirFlowRate.is_initialized
           autosizedDesignSupplyAirFlowRate.get
         else
           designSupplyAirFlowRate.get
         end
  v_ps_cfm = OpenStudio.convert(v_ps, 'm^3/s', 'cfm').get

  # Average outdoor air fraction
  x_s = v_ou / v_ps

  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "For #{name}: v_ou = #{v_ou_cfm.round} cfm, v_ps = #{v_ps_cfm.round} cfm, x_s = #{x_s.round(2)}.")

  # Determine the zone ventilation effectiveness
  # for every zone on the system.
  # When ventilation effectiveness is too low,
  # increase the minimum damper position.
  e_vzs = []
  e_vzs_adj = []
  num_zones_adj = 0
  thermalZones.sort.each do |zone|
    # Breathing zone airflow rate
    v_bz = zone.outdoor_airflow_rate

    # Zone air distribution, assumed 1 per PNNL
    e_z = 1.0

    # Zone airflow rate
    v_oz = v_bz / e_z

    # Primary design airflow rate
    # max of heating and cooling
    # design air flow rates
    v_pz = 0.0
    clg_dsn_flow = zone.autosizedCoolingDesignAirFlowRate
    if clg_dsn_flow.is_initialized
      clg_dsn_flow = clg_dsn_flow.get
      if clg_dsn_flow > v_pz
        v_pz = clg_dsn_flow
      end
    else
      OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}: #{zone.name} clg_dsn_flow could not be found.")
    end
    htg_dsn_flow = zone.autosizedHeatingDesignAirFlowRate
    if htg_dsn_flow.is_initialized
      htg_dsn_flow = htg_dsn_flow.get
      if htg_dsn_flow > v_pz
        v_pz = htg_dsn_flow
      end
    else
      OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}: #{zone.name} htg_dsn_flow could not be found.")
    end

    # Get the minimum damper position
    mdp_term = 1.0
    min_zn_flow = 0.0
    zone.equipment.each do |equip|
      if equip.to_AirTerminalSingleDuctVAVHeatAndCoolNoReheat.is_initialized
        term = equip.to_AirTerminalSingleDuctVAVHeatAndCoolNoReheat.get
        mdp_term = term.zoneMinimumAirFlowFraction
      elsif equip.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.is_initialized
        term = equip.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.get
        mdp_term = term.zoneMinimumAirFlowFraction
      elsif equip.to_AirTerminalSingleDuctVAVNoReheat.is_initialized
        term = equip.to_AirTerminalSingleDuctVAVNoReheat.get
        if term.constantMinimumAirFlowFraction.is_initialized
          mdp_term = term.constantMinimumAirFlowFraction.get
        end
      elsif equip.to_AirTerminalSingleDuctVAVReheat.is_initialized
        term = equip.to_AirTerminalSingleDuctVAVReheat.get
        mdp_term = term.constantMinimumAirFlowFraction
        min_zn_flow = term.fixedMinimumAirFlowRate
      end
    end

    # For VAV Reheat terminals, min flow is greater of mdp
    # and min flow rate / design flow rate.
    mdp = mdp_term
    mdp_oa = min_zn_flow / v_ps
    if min_zn_flow > 0.0
      mdp = [mdp_term, mdp_oa].max.round(2)
    end
    # OpenStudio::logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{self.name}: Zone #{zone.name} mdp_term = #{mdp_term.round(2)}, mdp_oa = #{mdp_oa.round(2)}; mdp_final = #{mdp}")

    # Zone minimum discharge airflow rate
    v_dz = v_pz * mdp

    # Zone discharge air fraction
    z_d = v_oz / v_dz

    # Zone ventilation effectiveness
    e_vz = 1 + x_s - z_d

    # Store the ventilation effectiveness
    e_vzs << e_vz

    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "For #{name}: Zone #{zone.name} v_oz = #{v_oz.round(2)} m^3/s, v_pz = #{v_pz.round(2)} m^3/s, v_dz = #{v_dz.round(2)}, z_d = #{z_d.round(2)}.")

    # Check the ventilation effectiveness against
    # the minimum limit per PNNL and increase
    # as necessary.
    if e_vz < 0.6

      # Adjusted discharge air fraction
      z_d_adj = 1 + x_s - 0.6

      # Adjusted min discharge airflow rate
      v_dz_adj = v_oz / z_d_adj

      # Adjusted minimum damper position
      mdp_adj = v_dz_adj / v_pz

      # Don't allow values > 1
      if mdp_adj > 1.0
        mdp_adj = 1.0
      end

      # Zone ventilation effectiveness
      e_vz_adj = 1 + x_s - z_d_adj

      # Store the ventilation effectiveness
      e_vzs_adj << e_vz_adj

      # Set the adjusted minimum damper position
      zone.equipment.each do |equip|
        if equip.to_AirTerminalSingleDuctVAVHeatAndCoolNoReheat.is_initialized
          term = equip.to_AirTerminalSingleDuctVAVHeatAndCoolNoReheat.get
          term.setZoneMinimumAirFlowFraction(mdp_adj)
        elsif equip.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.is_initialized
          term = equip.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.get
          term.setZoneMinimumAirFlowFraction(mdp_adj)
        elsif equip.to_AirTerminalSingleDuctVAVNoReheat.is_initialized
          term = equip.to_AirTerminalSingleDuctVAVNoReheat.get
          term.setConstantMinimumAirFlowFraction(mdp_adj)
        elsif equip.to_AirTerminalSingleDuctVAVReheat.is_initialized
          term = equip.to_AirTerminalSingleDuctVAVReheat.get
          term.setConstantMinimumAirFlowFraction(mdp_adj)
        end
      end

      num_zones_adj += 1

      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Zone #{zone.name} has a ventilation effectiveness of #{e_vz.round(2)}.  Increasing to #{e_vz_adj.round(2)} by increasing minimum damper position from #{mdp.round(2)} to #{mdp_adj.round(2)}.")

    else
      # Store the unadjusted value
      e_vzs_adj << e_vz
    end
  end

  # Min system zone ventilation effectiveness
  e_v = e_vzs.min

  # Total system outdoor intake flow rate
  v_ot = v_ou / e_v
  v_ot_cfm = OpenStudio.convert(v_ot, 'm^3/s', 'cfm').get

  # Min system zone ventilation effectiveness
  e_v_adj = e_vzs_adj.min

  # Total system outdoor intake flow rate
  v_ot_adj = v_ou / e_v_adj
  v_ot_adj_cfm = OpenStudio.convert(v_ot_adj, 'm^3/s', 'cfm').get

  # Report out the results of the multizone calculations
  if num_zones_adj > 0
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: the multizone outdoor air calculation method was applied.  A simple summation of the zone outdoor air requirements gives a value of #{v_ou_cfm.round} cfm.  Applying the multizone method gives a value of #{v_ot_cfm.round} cfm, with an original system ventilation effectiveness of #{e_v.round(2)}.  After increasing the minimum damper position in #{num_zones_adj} critical zones, the resulting requirement is #{v_ot_adj_cfm.round} cfm with a system ventilation effectiveness of #{e_v_adj.round(2)}.")
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: the multizone outdoor air calculation method was applied.  A simple summation of the zone requirements gives a value of #{v_ou_cfm.round} cfm.  However, applying the multizone method requires #{v_ot_adj_cfm.round} cfm based on the ventilation effectiveness of the system.")
  end

  # Hard-size the sizing:system
  # object with the calculated min OA flow rate
  sizing_system = sizingSystem
  sizing_system.setDesignOutdoorAirFlowRate(v_ot_adj)

  return true
end

#adjust_minimum_vav_damper_positions_outpatient ⇒ Object

For critical zones of Outpatient, if the minimum airflow rate required by the accreditation standard (AIA 2001) is significantly less than the autosized peak design airflow in any of the three climate zones (Houston, Baltimore and Burlington), the minimum airflow fraction of the terminal units is reduced to the value: “required minimum airflow rate / autosized peak design flow” Reference: <Achieving the 30% Goal: Energy and Cost Savings Analysis of ASHRAE Standard 90.1-2010> Page109-111 For implementation purpose, since it is time-consuming to perform autosizing in three climate zones, just use the results of the current climate zone



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2217

def adjust_minimum_vav_damper_positions_outpatient
  model.getSpaces.each do |space|
    zone = space.thermalZone.get
    sizing_zone = zone.sizingZone
    space_area = space.floorArea
    if sizing_zone.coolingDesignAirFlowMethod == 'DesignDay'
      next
    elsif sizing_zone.coolingDesignAirFlowMethod == 'DesignDayWithLimit'
      minimum_airflow_per_zone_floor_area = sizing_zone.coolingMinimumAirFlowperZoneFloorArea
      minimum_airflow_per_zone = minimum_airflow_per_zone_floor_area * space_area
      # get the autosized maximum air flow of the VAV terminal
      zone.equipment.each do |equip|
        if equip.to_AirTerminalSingleDuctVAVReheat.is_initialized
          vav_terminal = equip.to_AirTerminalSingleDuctVAVReheat.get
          rated_maximum_flow_rate = vav_terminal.autosizedMaximumAirFlowRate.get
          # compare the VAV autosized maximum airflow with the minimum airflow rate required by the accreditation standard
          ratio = minimum_airflow_per_zone / rated_maximum_flow_rate
          if ratio >= 0.95
            vav_terminal.setConstantMinimumAirFlowFraction(1)
          elsif ratio < 0.95
            vav_terminal.setConstantMinimumAirFlowFraction(ratio)
          end
        end
      end
    end
  end
  return true
end

#allowable_system_brake_horsepower(template = 'ASHRAE 90.1-2007') ⇒ Double

Determine the allowable fan system brake horsepower Per Table 6.5.3.1.1A

Parameters:

  • template (String) (defaults to: 'ASHRAE 90.1-2007') —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

Returns:

  • (Double) —

    allowable fan system brake horsepower units = horsepower



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 281

def allowable_system_brake_horsepower(template = 'ASHRAE 90.1-2007')
  # Get design supply air flow rate (whether autosized or hard-sized)
  dsn_air_flow_m3_per_s = 0
  dsn_air_flow_cfm = 0
  if autosizedDesignSupplyAirFlowRate.is_initialized
    dsn_air_flow_m3_per_s = autosizedDesignSupplyAirFlowRate.get
    dsn_air_flow_cfm = OpenStudio.convert(dsn_air_flow_m3_per_s, 'm^3/s', 'cfm').get
    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "* #{dsn_air_flow_cfm.round} cfm = Autosized Design Supply Air Flow Rate.")
  else
    dsn_air_flow_m3_per_s = designSupplyAirFlowRate.get
    dsn_air_flow_cfm = OpenStudio.convert(dsn_air_flow_m3_per_s, 'm^3/s', 'cfm').get
    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "* #{dsn_air_flow_cfm.round} cfm = Hard sized Design Supply Air Flow Rate.")
  end

  # Get the fan limitation pressure drop adjustment bhp
  fan_pwr_adjustment_bhp = fan_power_limitation_pressure_drop_adjustment_brake_horsepower

  # Determine the number of zones the system serves
  num_zones_served = thermalZones.size

  # Get the supply air fan and determine whether VAV or CAV system.
  # Assume that supply air fan is fan closest to the demand outlet node.
  # The fan may be inside of a piece of unitary equipment.
  fan_pwr_limit_type = nil
  supplyComponents.reverse.each do |comp|
    if comp.to_FanConstantVolume.is_initialized || comp.to_FanOnOff.is_initialized
      fan_pwr_limit_type = 'constant volume'
    elsif comp.to_FanVariableVolume.is_initialized
      fan_pwr_limit_type = 'variable volume'
    elsif comp.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.is_initialized
      fan = comp.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.get.supplyAirFan
      if fan.to_FanConstantVolume.is_initialized || comp.to_FanOnOff.is_initialized
        fan_pwr_limit_type = 'constant volume'
      elsif fan.to_FanVariableVolume.is_initialized
        fan_pwr_limit_type = 'variable volume'
      end
    elsif comp.to_AirLoopHVACUnitarySystem.is_initialized
      fan = comp.to_AirLoopHVACUnitarySystem.get.supplyFan
      if fan.to_FanConstantVolume.is_initialized || comp.to_FanOnOff.is_initialized
        fan_pwr_limit_type = 'constant volume'
      elsif fan.to_FanVariableVolume.is_initialized
        fan_pwr_limit_type = 'variable volume'
      end
    end
  end

  # For 90.1-2010, single-zone VAV systems use the
  # constant volume limitation per 6.5.3.1.1
  if template == 'ASHRAE 90.1-2010' && fan_pwr_limit_type == 'variable volume' && num_zones_served == 1
    fan_pwr_limit_type = 'constant volume'
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Using the constant volume limitation because single-zone VAV system.")
  end

  # Calculate the Allowable Fan System brake horsepower per Table G3.1.2.9
  allowable_fan_bhp = 0
  if fan_pwr_limit_type == 'constant volume'
    allowable_fan_bhp = dsn_air_flow_cfm * 0.00094 + fan_pwr_adjustment_bhp
  elsif fan_pwr_limit_type == 'variable volume'
    allowable_fan_bhp = dsn_air_flow_cfm * 0.0013 + fan_pwr_adjustment_bhp
  end
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Allowable brake horsepower = #{allowable_fan_bhp.round(2)}HP based on #{dsn_air_flow_cfm.round} cfm and #{fan_pwr_adjustment_bhp.round(2)} bhp of adjustment.")

  # Calculate and report the total area for debugging/testing
  floor_area_served_m2 = floor_area_served
  floor_area_served_ft2 = OpenStudio.convert(floor_area_served_m2, 'm^2', 'ft^2').get
  cfm_per_ft2 = dsn_air_flow_cfm / floor_area_served_ft2
  cfm_per_hp = dsn_air_flow_cfm / allowable_fan_bhp
  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "For #{name}: area served = #{floor_area_served_ft2.round} ft^2.")
  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "For #{name}: flow per area = #{cfm_per_ft2.round} cfm/ft^2.")
  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "For #{name}: flow per hp = #{cfm_per_hp.round} cfm/hp.")

  return allowable_fan_bhp
end

#apply_baseline_fan_pressure_rise(template = 'ASHRAE 90.1-2007') ⇒ Object

Set the fan pressure rises that will result in the system hitting the baseline allowable fan power

Parameters:

  • template (String) (defaults to: 'ASHRAE 90.1-2007') —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 440

def apply_baseline_fan_pressure_rise(template = 'ASHRAE 90.1-2007')
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "#{name}-Setting #{template} baseline fan power.")

  # Get the total system bhp from the proposed system, including terminal fans
  proposed_sys_bhp = system_fan_brake_horsepower(true)

  # Get the allowable fan brake horsepower
  allowable_fan_bhp = allowable_system_brake_horsepower(template)

  # Get the fan power limitation from proposed system
  fan_pwr_adjustment_bhp = fan_power_limitation_pressure_drop_adjustment_brake_horsepower

  # Subtract the fan power adjustment
  allowable_fan_bhp -= fan_pwr_adjustment_bhp

  # Get all fans
  fans = supply_return_exhaust_relief_fans

  # TODO: improve description
  # Loop through the fans, changing the pressure rise
  # until the fan bhp is the same percentage of the baseline allowable bhp
  # as it was on the proposed system.
  fans.each do |fan|
    # TODO: Yixing Check the model of the Fan Coil Unit
    next if fan.name.to_s.include?('Fan Coil fan')
    next if fan.name.to_s.include?('UnitHeater Fan')

    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', fan.name.to_s)

    # Get the bhp of the fan on the proposed system
    proposed_fan_bhp = fan.brake_horsepower

    # Get the bhp of the fan on the proposed system
    proposed_fan_bhp_frac = proposed_fan_bhp / proposed_sys_bhp

    # Determine the target bhp of the fan on the baseline system
    baseline_fan_bhp = proposed_fan_bhp_frac * allowable_fan_bhp
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "* #{baseline_fan_bhp.round(1)} bhp = Baseline fan brake horsepower.")

    # Set the baseline impeller eff of the fan,
    # preserving the proposed motor eff.
    baseline_impeller_eff = fan.baseline_impeller_efficiency(template)
    fan.change_impeller_efficiency(baseline_impeller_eff)
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "* #{(baseline_impeller_eff * 100).round(1)}% = Baseline fan impeller efficiency.")

    # Set the baseline motor efficiency for the specified bhp
    baseline_motor_eff = fan.standardMinimumMotorEfficiency(template, standards, allowable_fan_bhp)
    fan.change_motor_efficiency(baseline_motor_eff)

    # Get design supply air flow rate (whether autosized or hard-sized)
    dsn_air_flow_m3_per_s = 0
    if fan.autosizedDesignSupplyAirFlowRate.is_initialized
      dsn_air_flow_m3_per_s = fan.autosizedDesignSupplyAirFlowRate.get
      dsn_air_flow_cfm = OpenStudio.convert(dsn_air_flow_m3_per_s, 'm^3/s', 'cfm').get
      OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "* #{dsn_air_flow_cfm.round} cfm = Autosized Design Supply Air Flow Rate.")
    else
      dsn_air_flow_m3_per_s = fan.designSupplyAirFlowRate.get
      dsn_air_flow_cfm = OpenStudio.convert(dsn_air_flow_m3_per_s, 'm^3/s', 'cfm').get
      OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "* #{dsn_air_flow_cfm.round} cfm = User entered Design Supply Air Flow Rate.")
    end

    # Determine the fan pressure rise that will result in the target bhp
    # pressure_rise_pa = fan_bhp*746 / fan_motor_eff*fan_total_eff / dsn_air_flow_m3_per_s
    baseline_pressure_rise_pa = baseline_fan_bhp * 746 / fan.motorEfficiency * fan.fanEfficiency / dsn_air_flow_m3_per_s
    baseline_pressure_rise_in_wc = OpenStudio.convert(fan_pressure_rise_pa, 'Pa', 'inH_{2}O').get
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "* #{fan_pressure_rise_in_wc.round(2)} in w.c. = Pressure drop to achieve allowable fan power.")

    # Calculate the bhp of the fan to make sure it matches
    calc_bhp = fan.brake_horsepower
    if ((calc_bhp - baseline_fan_bhp) / baseline_fan_bhp).abs > 0.02
      OpenStudio.logFree(OpenStudio::Error, 'openstudio.standards.AirLoopHVAC', "#{fan.name} baseline fan bhp supposed to be #{baseline_fan_bhp}, but is #{calc_bhp}.")
    end
  end

  # Calculate the total bhp of the system to make sure it matches the goal
  calc_sys_bhp = system_fan_brake_horsepower(false)
  if ((calc_sys_bhp - allowable_fan_bhp) / allowable_fan_bhp).abs > 0.02
    OpenStudio.logFree(OpenStudio::Error, 'openstudio.standards.AirLoopHVAC', "#{name} baseline system bhp supposed to be #{allowable_fan_bhp}, but is #{calc_sys_bhp}.")
  end
end

#apply_economizer_integration(template, climate_zone) ⇒ Bool

Note:

this method assumes you previously checked that an economizer is required at all via #economizer_required?

For systems required to have an economizer, set the economizer to integrated on non-integrated per the standard.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 933

def apply_economizer_integration(template, climate_zone)
  # Determine if the system is a VAV system based on the fan
  # which may be inside of a unitary system.
  is_vav = false
  supplyComponents.reverse.each do |comp|
    if comp.to_FanVariableVolume.is_initialized
      is_vav = true
    elsif comp.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.is_initialized
      fan = comp.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.get.supplyAirFan
      if fan.to_FanVariableVolume.is_initialized
        is_vav = true
      end
    elsif comp.to_AirLoopHVACUnitarySystem.is_initialized
      fan = comp.to_AirLoopHVACUnitarySystem.get.supplyFan
      if fan.is_initialized
        if fan.get.to_FanVariableVolume.is_initialized
          is_vav = true
        end
      end
    end
  end

  # Determine the number of zones the system serves
  num_zones_served = thermalZones.size

  # A big number of btu per hr as the minimum requirement
  infinity_btu_per_hr = 999_999_999_999
  minimum_capacity_btu_per_hr = infinity_btu_per_hr

  # Determine if an integrated economizer is required
  integrated_economizer_required = true
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007'
    minimum_capacity_btu_per_hr = 65_000
    minimum_capacity_w = OpenStudio.convert(minimum_capacity_btu_per_hr, 'Btu/hr', 'W').get
    # 6.5.1.3 Integrated Economizer Control
    # Exception a, DX VAV systems
    if is_vav == true && num_zones_served > 1
      integrated_economizer_required = false
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: non-integrated economizer per 6.5.1.3 exception a, DX VAV system.")
      # Exception b, DX units less than 65,000 Btu/hr
    elsif total_cooling_capacity < minimum_capacity_w
      integrated_economizer_required = false
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: non-integrated economizer per 6.5.1.3 exception b, DX system less than #{minimum_capacity_btu_per_hr}Btu/hr.")
    else
      # Exception c, Systems in climate zones 1,2,3a,4a,5a,5b,6,7,8
      case climate_zone
      when 'ASHRAE 169-2006-1A',
          'ASHRAE 169-2006-1B',
          'ASHRAE 169-2006-2A',
          'ASHRAE 169-2006-2B',
          'ASHRAE 169-2006-3A',
          'ASHRAE 169-2006-4A',
          'ASHRAE 169-2006-5A',
          'ASHRAE 169-2006-5B',
          'ASHRAE 169-2006-6A',
          'ASHRAE 169-2006-6B',
          'ASHRAE 169-2006-7A',
          'ASHRAE 169-2006-7B',
          'ASHRAE 169-2006-8A',
          'ASHRAE 169-2006-8B'
        integrated_economizer_required = false
        OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: non-integrated economizer per 6.5.1.3 exception c, climate zone #{climate_zone}.")
      when 'ASHRAE 169-2006-3B',
          'ASHRAE 169-2006-3C',
          'ASHRAE 169-2006-4B',
          'ASHRAE 169-2006-4C',
          'ASHRAE 169-2006-5C'
        integrated_economizer_required = true
      end
    end
  when '90.1-2010', '90.1-2013'
    integrated_economizer_required = true
  when 'NECB 2011'
    # this means that compressor allowed to turn on when economizer is open
    # (NoLockout); as per 5.2.2.8(3)
    integrated_economizer_required = true
  end

  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir

  # Apply integrated or non-integrated economizer
  if integrated_economizer_required
    oa_control.setLockoutType('NoLockout')
  else
    oa_control.setLockoutType('LockoutWithCompressor')
  end

  return true
end

#apply_economizer_limits(template, climate_zone) ⇒ Bool

Set the economizer limits per the standard. Limits are based on the economizer type currently specified in the ControllerOutdoorAir object on this air loop.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 799

def apply_economizer_limits(template, climate_zone)
  # EnergyPlus economizer types
  # 'NoEconomizer'
  # 'FixedDryBulb'
  # 'FixedEnthalpy'
  # 'DifferentialDryBulb'
  # 'DifferentialEnthalpy'
  # 'FixedDewPointAndDryBulb'
  # 'ElectronicEnthalpy'
  # 'DifferentialDryBulbAndEnthalpy'

  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir
  economizer_type = oa_control.getEconomizerControlType

  # Return false if no economizer is present
  if economizer_type == 'NoEconomizer'
    return false
  end

  # Determine the limits according to the type
  drybulb_limit_f = nil
  enthalpy_limit_btu_per_lb = nil
  dewpoint_limit_f = nil
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007'
    case economizer_type
    when 'FixedDryBulb'
      case climate_zone
      when 'ASHRAE 169-2006-1B',
          'ASHRAE 169-2006-2B',
          'ASHRAE 169-2006-3B',
          'ASHRAE 169-2006-3C',
          'ASHRAE 169-2006-4B',
          'ASHRAE 169-2006-4C',
          'ASHRAE 169-2006-5B',
          'ASHRAE 169-2006-5C',
          'ASHRAE 169-2006-6B',
          'ASHRAE 169-2006-7B',
          'ASHRAE 169-2006-8A',
          'ASHRAE 169-2006-8B'
        drybulb_limit_f = 75
      when 'ASHRAE 169-2006-5A',
          'ASHRAE 169-2006-6A',
          'ASHRAE 169-2006-7A'
        drybulb_limit_f = 70
      when 'ASHRAE 169-2006-1A',
          'ASHRAE 169-2006-2A',
          'ASHRAE 169-2006-3A',
          'ASHRAE 169-2006-4A'
        drybulb_limit_f = 65
      end
    when 'FixedEnthalpy'
      enthalpy_limit_btu_per_lb = 28
    when 'FixedDewPointAndDryBulb'
      drybulb_limit_f = 75
      dewpoint_limit_f = 55
    end
  when '90.1-2010', '90.1-2013'
    case economizer_type
    when 'FixedDryBulb'
      case climate_zone
      when 'ASHRAE 169-2006-1B',
          'ASHRAE 169-2006-2B',
          'ASHRAE 169-2006-3B',
          'ASHRAE 169-2006-3C',
          'ASHRAE 169-2006-4B',
          'ASHRAE 169-2006-4C',
          'ASHRAE 169-2006-5B',
          'ASHRAE 169-2006-5C',
          'ASHRAE 169-2006-6B',
          'ASHRAE 169-2006-7A',
          'ASHRAE 169-2006-7B',
          'ASHRAE 169-2006-8A',
          'ASHRAE 169-2006-8B'
        drybulb_limit_f = 75
      when 'ASHRAE 169-2006-5A',
          'ASHRAE 169-2006-6A'
        drybulb_limit_f = 70
      end
    when 'FixedEnthalpy'
      enthalpy_limit_btu_per_lb = 28
    when 'FixedDewPointAndDryBulb'
      drybulb_limit_f = 75
      dewpoint_limit_f = 55
    end
  end

  # Reset the limits
  oa_control.resetEconomizerMaximumLimitDryBulbTemperature
  oa_control.resetEconomizerMaximumLimitEnthalpy
  oa_control.resetEconomizerMaximumLimitDewpointTemperature
  oa_control.resetEconomizerMinimumLimitDryBulbTemperature

  # Set the limits
  case economizer_type
  when 'FixedDryBulb'
    if drybulb_limit_f
      drybulb_limit_c = OpenStudio.convert(drybulb_limit_f, 'F', 'C').get
      oa_control.setEconomizerMaximumLimitDryBulbTemperature(drybulb_limit_c)
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer type = #{economizer_type}, dry bulb limit = #{drybulb_limit_f}F")
    end
  when 'FixedEnthalpy'
    if enthalpy_limit_btu_per_lb
      enthalpy_limit_j_per_kg = OpenStudio.convert(enthalpy_limit_btu_per_lb, 'Btu/lb', 'J/kg').get
      oa_control.setEconomizerMaximumLimitEnthalpy(enthalpy_limit_j_per_kg)
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer type = #{economizer_type}, enthalpy limit = #{enthalpy_limit_btu_per_lb}Btu/lb")
    end
  when 'FixedDewPointAndDryBulb'
    if drybulb_limit_f && dewpoint_limit_f
      drybulb_limit_c = OpenStudio.convert(drybulb_limit_f, 'F', 'C').get
      dewpoint_limit_c = OpenStudio.convert(dewpoint_limit_f, 'F', 'C').get
      oa_control.setEconomizerMaximumLimitDryBulbTemperature(drybulb_limit_c)
      oa_control.setEconomizerMaximumLimitDewpointTemperature(dewpoint_limit_c)
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer type = #{economizer_type}, dry bulb limit = #{drybulb_limit_f}F, dew-point limit = #{dewpoint_limit_f}F")
    end
  end

  return true
end

#apply_energy_recovery_ventilator(template) ⇒ Bool

TODO:

Add exception logic for systems serving parking garage, warehouse, or multifamily

Add an ERV to this airloop. Will be a rotary-type HX

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1790

def apply_energy_recovery_ventilator(template)
  # Get the oa system
  oa_system = nil
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV cannot be added because the system has no OA intake.")
    return false
  end

  # Create an ERV
  erv = OpenStudio::Model::HeatExchangerAirToAirSensibleAndLatent.new(model)
  erv.setName("#{name} ERV")
  if template == 'NECB 2011'
    erv.setSensibleEffectivenessat100HeatingAirFlow(0.5)
    erv.setLatentEffectivenessat100HeatingAirFlow(0.5)
    erv.setSensibleEffectivenessat75HeatingAirFlow(0.5)
    erv.setLatentEffectivenessat75HeatingAirFlow(0.5)
    erv.setSensibleEffectivenessat100CoolingAirFlow(0.5)
    erv.setLatentEffectivenessat100CoolingAirFlow(0.5)
    erv.setSensibleEffectivenessat75CoolingAirFlow(0.5)
    erv.setLatentEffectivenessat75CoolingAirFlow(0.5)
  else
    erv.setSensibleEffectivenessat100HeatingAirFlow(0.7)
    erv.setLatentEffectivenessat100HeatingAirFlow(0.6)
    erv.setSensibleEffectivenessat75HeatingAirFlow(0.7)
    erv.setLatentEffectivenessat75HeatingAirFlow(0.6)
    erv.setSensibleEffectivenessat100CoolingAirFlow(0.75)
    erv.setLatentEffectivenessat100CoolingAirFlow(0.6)
    erv.setSensibleEffectivenessat75CoolingAirFlow(0.75)
    erv.setLatentEffectivenessat75CoolingAirFlow(0.6)
  end
  erv.setSupplyAirOutletTemperatureControl(true)
  erv.setHeatExchangerType('Rotary')
  erv.setFrostControlType('ExhaustOnly')
  erv.setEconomizerLockout(true)
  erv.setThresholdTemperature(-23.3) # -10F
  erv.setInitialDefrostTimeFraction(0.167)
  erv.setRateofDefrostTimeFractionIncrease(1.44)

  # Add the ERV to the OA system
  erv.addToNode(oa_system.outboardOANode.get)

  # Add a setpoint manager OA pretreat
  # to control the ERV
  spm_oa_pretreat = OpenStudio::Model::SetpointManagerOutdoorAirPretreat.new(model)
  spm_oa_pretreat.setMinimumSetpointTemperature(-99.0)
  spm_oa_pretreat.setMaximumSetpointTemperature(99.0)
  spm_oa_pretreat.setMinimumSetpointHumidityRatio(0.00001)
  spm_oa_pretreat.setMaximumSetpointHumidityRatio(1.0)
  # Reference setpoint node and
  # Mixed air stream node are outlet
  # node of the OA system
  mixed_air_node = oa_system.mixedAirModelObject.get.to_Node.get
  spm_oa_pretreat.setReferenceSetpointNode(mixed_air_node)
  spm_oa_pretreat.setMixedAirStreamNode(mixed_air_node)
  # Outdoor air node is
  # the outboard OA node of teh OA system
  spm_oa_pretreat.setOutdoorAirStreamNode(oa_system.outboardOANode.get)
  # Return air node is the inlet
  # node of the OA system
  return_air_node = oa_system.returnAirModelObject.get.to_Node.get
  spm_oa_pretreat.setReturnAirStreamNode(return_air_node)
  # Attach to the outlet of the ERV
  erv_outlet = erv.primaryAirOutletModelObject.get.to_Node.get
  spm_oa_pretreat.addToNode(erv_outlet)

  # Apply the prototype Heat Exchanger power assumptions.
  erv.apply_prototype_nominal_electric_power

  return true
end

#apply_maximum_reheat_temperature(max_reheat_c) ⇒ Bool

Sets the maximum reheat temperature to the specified value for all reheat terminals (of any type) on the loop.

Parameters:

  • max_reheat_c (Double) —

    the maximum reheat temperature, in C

Returns:

  • (Bool) —

    returns true if successful, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3600

def apply_maximum_reheat_temperature(max_reheat_c)
  demandComponents.each do |sc|
    if sc.to_AirTerminalSingleDuctConstantVolumeReheat.is_initialized
      term = sc.to_AirTerminalSingleDuctConstantVolumeReheat.get
      term.setMaximumReheatAirTemperature(max_reheat_c)
    elsif sc.to_AirTerminalSingleDuctParallelPIUReheat.is_initialized
      # No control option available
    elsif sc.to_AirTerminalSingleDuctSeriesPIUReheat.is_initialized
      # No control option available
    elsif sc.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.is_initialized
      term = sc.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.get
      term.setMaximumReheatAirTemperature(max_reheat_c)
    elsif sc.to_AirTerminalSingleDuctVAVReheat.is_initialized
      term = sc.to_AirTerminalSingleDuctVAVReheat.get
      term.setMaximumReheatAirTemperature(max_reheat_c)
    end
  end

  max_reheat_f = OpenStudio.convert(max_reheat_c, 'C', 'F').get
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: reheat terminal maximum set to #{max_reheat_f.round} F.")

  return true
end

#apply_minimum_vav_damper_positions(template, has_ddc = true) ⇒ Bool

Set the minimum VAV damper positions.

is DDC control of vav terminals. If false, assumes otherwise.

Parameters:

  • template (String) —

    the building template

  • has_ddc (Bool) (defaults to: true) —

    if true, will assume that there

Returns:

  • (Bool) —

    true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2002

def apply_minimum_vav_damper_positions(template, has_ddc = true)
  thermalZones.each do |zone|
    zone.equipment.each do |equip|
      if equip.to_AirTerminalSingleDuctVAVReheat.is_initialized
        zone_oa = zone.outdoor_airflow_rate
        vav_terminal = equip.to_AirTerminalSingleDuctVAVReheat.get
        vav_terminal.apply_minimum_damper_position(template, zone_oa, has_ddc)
      end
    end
  end

  return true
end

#apply_multizone_vav_outdoor_air_sizing(template) ⇒ Object

Apply multizone vav outdoor air method and adjust multizone VAV damper positions to achieve a system minimum ventilation effectiveness of 0.6 per PNNL. Hard-size the resulting min OA into the sizing:system object.

return [Bool] returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 11

def apply_multizone_vav_outdoor_air_sizing(template)
  # TODO: enable damper position adjustment for legacy IDFS
  if template == 'DOE Ref Pre-1980' || template == 'DOE Ref 1980-2004'
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', 'Damper positions not modified for DOE Ref Pre-1980 or DOE Ref 1980-2004 vintages.')
    return true
  end

  # First time adjustment:
  # Only applies to multi-zone vav systems
  # exclusion: for Outpatient: (1) both AHU1 and AHU2 in 'DOE Ref Pre-1980' and 'DOE Ref 1980-2004'
  # (2) AHU1 in 2004-2013
  if multizone_vav_system? && !(name.to_s.include? 'Outpatient F1')
    adjust_minimum_vav_damper_positions
  end

  # Second time adjustment:
  # Only apply to 2010 and 2013 Outpatient (both AHU1 and AHU2)
  # TODO maybe apply to hospital as well?
  if (name.to_s.include? 'Outpatient') && (template == '90.1-2010' || template == '90.1-2013')
    adjust_minimum_vav_damper_positions_outpatient
  end

  return true
end

#apply_prm_baseline_controls(template, climate_zone) ⇒ Bool

Apply all PRM baseline required controls to the airloop. Only applies those controls that differ from the normal prescriptive controls, which are added via AirLoopHVAC.apply_standard_controls

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 151

def apply_prm_baseline_controls(template, climate_zone)
  # Economizers
  if prm_baseline_economizer_required?(template, climate_zone)
    apply_prm_baseline_economizer(template, climate_zone)
  end

  # Multizone VAV Systems
  if multizone_vav_system?

    # VSD no Static Pressure Reset on all VAV systems
    # per G3.1.3.15
    supply_return_exhaust_relief_fans.each do |fan|
      if fan.to_FanVariableVolume.is_initialized
        OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Setting fan part load curve per G3.1.3.15.")
        fan.set_control_type('Multi Zone VAV with VSD and Fixed SP Setpoint')
      end
    end

    # SAT Reset
    # G3.1.3.12 SAT reset required for all Multizone VAV systems,
    # even if not required by prescriptive section.
    case template
    when '90.1-2004', '90.1-2007', '90.1-2010', '90.1-2013'
      enable_supply_air_temperature_reset_warmest_zone(template)
    end

  end

  # Unoccupied shutdown
  enable_unoccupied_fan_shutoff

  return true
end

#apply_prm_baseline_economizer(template, climate_zone) ⇒ Bool

Apply the PRM economizer type and set temperature limits

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1118

def apply_prm_baseline_economizer(template, climate_zone)
  # EnergyPlus economizer types
  # 'NoEconomizer'
  # 'FixedDryBulb'
  # 'FixedEnthalpy'
  # 'DifferentialDryBulb'
  # 'DifferentialEnthalpy'
  # 'FixedDewPointAndDryBulb'
  # 'ElectronicEnthalpy'
  # 'DifferentialDryBulbAndEnthalpy'

  # Determine the type and limits
  economizer_type = 'NoEconomizer'
  drybulb_limit_f = nil
  enthalpy_limit_btu_per_lb = nil
  dewpoint_limit_f = nil
  case template
  when '90.1-2004', '90.1-2007', '90.1-2010'
    case climate_zone
    when 'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
        'ASHRAE 169-2006-4B',
        'ASHRAE 169-2006-4C',
        'ASHRAE 169-2006-5B',
        'ASHRAE 169-2006-5C',
        'ASHRAE 169-2006-6B',
        'ASHRAE 169-2006-7B',
        'ASHRAE 169-2006-8A',
        'ASHRAE 169-2006-8B'
      economizer_type = 'FixedDryBulb'
      drybulb_limit_f = 75
    when 'ASHRAE 169-2006-5A',
        'ASHRAE 169-2006-6A',
        'ASHRAE 169-2006-7A'
      economizer_type = 'FixedDryBulb'
      drybulb_limit_f = 70
    else
      economizer_type = 'FixedDryBulb'
      drybulb_limit_f = 65
    end
  when '90.1-2013'
    case climate_zone
    when 'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
        'ASHRAE 169-2006-4B',
        'ASHRAE 169-2006-4C',
        'ASHRAE 169-2006-5B',
        'ASHRAE 169-2006-5C',
        'ASHRAE 169-2006-6B',
        'ASHRAE 169-2006-7A',
        'ASHRAE 169-2006-7B',
        'ASHRAE 169-2006-8A',
        'ASHRAE 169-2006-8B'
      economizer_type = 'FixedDryBulb'
      drybulb_limit_f = 75
    when 'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-4A'
      economizer_type = 'FixedEnthalpy'
      enthalpy_limit_btu_per_lb = 28
    when 'ASHRAE 169-2006-5A',
        'ASHRAE 169-2006-6A',
        'ASHRAE 169-2006-7A'
      economizer_type = 'FixedDryBulb'
      drybulb_limit_f = 70
    else
      economizer_type = 'FixedDryBulb'
      drybulb_limit_f = 65
    end
  end

  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir

  # Set the economizer type
  oa_control.setEconomizerControlType(economizer_type)

  # Reset the limits
  oa_control.resetEconomizerMaximumLimitDryBulbTemperature
  oa_control.resetEconomizerMaximumLimitEnthalpy
  oa_control.resetEconomizerMaximumLimitDewpointTemperature
  oa_control.resetEconomizerMinimumLimitDryBulbTemperature

  # Set the limits
  case economizer_type
  when 'FixedDryBulb'
    if drybulb_limit_f
      drybulb_limit_c = OpenStudio.convert(drybulb_limit_f, 'F', 'C').get
      oa_control.setEconomizerMaximumLimitDryBulbTemperature(drybulb_limit_c)
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer type = #{economizer_type}, dry bulb limit = #{drybulb_limit_f}F")
    end
  when 'FixedEnthalpy'
    if enthalpy_limit_btu_per_lb
      enthalpy_limit_j_per_kg = OpenStudio.convert(enthalpy_limit_btu_per_lb, 'Btu/lb', 'J/kg').get
      oa_control.setEconomizerMaximumLimitEnthalpy(enthalpy_limit_j_per_kg)
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer type = #{economizer_type}, enthalpy limit = #{enthalpy_limit_btu_per_lb}Btu/lb")
    end
  when 'FixedDewPointAndDryBulb'
    if drybulb_limit_f && dewpoint_limit_f
      drybulb_limit_c = OpenStudio.convert(drybulb_limit_f, 'F', 'C').get
      dewpoint_limit_c = OpenStudio.convert(dewpoint_limit_f, 'F', 'C').get
      oa_control.setEconomizerMaximumLimitDryBulbTemperature(drybulb_limit_c)
      oa_control.setEconomizerMaximumLimitDewpointTemperature(dewpoint_limit_c)
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer type = #{economizer_type}, dry bulb limit = #{drybulb_limit_f}F, dew-point limit = #{dewpoint_limit_f}F")
    end
  end

  return true
end

#apply_prm_baseline_fan_power(template) ⇒ Object

TODO:

Figure out how to split fan power between multiple fans

Calculate and apply the performance rating method baseline fan power to this air loop. Fan motor efficiency will be set, and then fan pressure rise adjusted so that the fan power is the maximum allowable. Also adjusts the fan power and flow rates of any parallel PIU terminals on the system.

if the proposed model had multiple fans (supply, return, exhaust, etc.) return [Bool] true if successful, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 196

def apply_prm_baseline_fan_power(template)
  # Main AHU fans

  # Calculate the allowable fan motor bhp
  # for the entire airloop.
  allowable_fan_bhp = allowable_system_brake_horsepower(template)

  # Divide the allowable power evenly between the fans
  # on this airloop.
  all_fans = supply_return_exhaust_relief_fans
  allowable_fan_bhp /= all_fans.size

  # Set the motor efficiencies
  # for all fans based on the calculated
  # allowed brake hp.  Then calculate the allowable
  # fan power for each fan and adjust
  # the fan pressure rise accordingly
  all_fans.each do |fan|
    fan.apply_standard_minimum_motor_efficiency(template, allowable_fan_bhp)
    allowable_power_w = allowable_fan_bhp * 746 / fan.motorEfficiency
    fan.adjust_pressure_rise_to_meet_fan_power(allowable_power_w)
  end

  # Fan powered terminal fans

  # Adjust each terminal fan
  demandComponents.each do |dc|
    next if dc.to_AirTerminalSingleDuctParallelPIUReheat.empty?
    pfp_term = dc.to_AirTerminalSingleDuctParallelPIUReheat.get
    pfp_term.apply_prm_baseline_fan_power(template)
  end

  return true
end

#apply_prm_sizing_temperatures ⇒ Bool

Set the system sizing properties based on the zone sizing information

Returns:

  • (Bool) —

    true if successful, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3627

def apply_prm_sizing_temperatures
  # Get the design heating and cooling SAT information
  # for all zones served by the system.
  htg_setpts_c = []
  clg_setpts_c = []
  thermalZones.each do |zone|
    sizing_zone = zone.sizingZone
    htg_setpts_c << sizing_zone.zoneHeatingDesignSupplyAirTemperature
    clg_setpts_c << sizing_zone.zoneCoolingDesignSupplyAirTemperature
  end

  # Cooling SAT set to minimum zone cooling design SAT
  clg_sat_c = clg_setpts_c.min

  # If the system has terminal reheat,
  # heating SAT is set to the same value as cooling SAT
  # and the terminals are expected to do the heating.
  # If not, heating SAT set to maximum zone heating design SAT.
  has_term_rht = terminal_reheat?
  htg_sat_c = if has_term_rht
                clg_sat_c
              else
                htg_setpts_c.max
              end

  # Set the central SAT values
  sizing_system = sizingSystem
  sizing_system.setCentralCoolingDesignSupplyAirTemperature(clg_sat_c)
  sizing_system.setCentralHeatingDesignSupplyAirTemperature(htg_sat_c)

  clg_sat_f = OpenStudio.convert(clg_sat_c, 'C', 'F').get
  htg_sat_f = OpenStudio.convert(htg_sat_c, 'C', 'F').get
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: central heating SAT set to #{htg_sat_f.round} F, cooling SAT set to #{clg_sat_f.round} F.")

  # If it's a terminal reheat system, set the reheat terminal setpoints too
  if has_term_rht
    rht_c = htg_setpts_c.max
    apply_maximum_reheat_temperature(rht_c)
  end

  return true
end

#apply_single_zone_controls(template, climate_zone) ⇒ Object

Note:

The resulting EMS doesn’t actually get added to

Generate the EMS used to implement the economizer and staging controls for packaged single zone units. the IDF yet.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3049

def apply_single_zone_controls(template, climate_zone)
  # Number of stages is determined by the template
  num_stages = nil
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', 'NECB 2011'
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: No special economizer controls were modeled.")
    return true
  when '90.1-2004', '90.1-2007'
    num_stages = 1
  when '90.1-2010', '90.1-2013'
    num_stages = 2
  end

  # Scrub special characters from the system name
  sn = name.get.to_s
  snc = sn.gsub(/\W/, '').delete('_')

  # Get the zone name
  zone = thermalZones[0]
  zone_name = zone.name.get.to_s
  zn_name_clean = zone_name.gsub(/\W/, '_')

  # Zone air node
  zone_air_node_name = zone.zoneAirNode.name.get

  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir
  oa_control_name = oa_control.name.get
  oa_node_name = oa_sys.outboardOANode.get.name.get

  # Get the name of the min oa schedule
  min_oa_sch_name = nil
  min_oa_sch_name = if oa_control.minimumOutdoorAirSchedule.is_initialized
                      oa_control.minimumOutdoorAirSchedule.get.name.get
                    else
                      model.alwaysOnDiscreteSchedule.name.get
                    end

  # Get the supply fan
  if supplyFan.empty?
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: No supply fan found, cannot apply DX fan/economizer control.")
    return false
  end
  fan = supplyFan.get
  fan_name = fan.name.get

  # Supply outlet node
  sup_out_node = supplyOutletNode
  sup_out_node_name = sup_out_node.name.get

  # DX Cooling Coil
  dx_coil = nil
  supplyComponents.each do |equip|
    if equip.to_CoilCoolingDXSingleSpeed.is_initialized
      dx_coil = equip.to_CoilCoolingDXSingleSpeed.get
    elsif equip.to_CoilCoolingDXTwoSpeed.is_initialized
      dx_coil = equip.to_CoilCoolingDXTwoSpeed.get
    end
  end
  if dx_coil.nil?
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: No DX cooling coil found, cannot apply DX fan/economizer control.")
    return false
  end
  dx_coil_name = dx_coil.name.get
  dx_coilsys_name = "#{dx_coil_name} CoilSystem"

  # Heating Coil
  htg_coil = nil
  supplyComponents.each do |equip|
    if equip.to_CoilHeatingGas.is_initialized
      htg_coil = equip.to_CoilHeatingGas.get
    elsif equip.to_CoilHeatingElectric.is_initialized
      htg_coil = equip.to_CoilHeatingElectric.get
    elsif equip.to_CoilHeatingWater.is_initialized
      htg_coil = equip.to_CoilHeatingWater.get
    end
  end
  if htg_coil.nil?
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: No heating coil found, cannot apply DX fan/economizer control.")
    return false
  end
  htg_coil_name = htg_coil.name.get

  # Create an economizer maximum OA fraction schedule with
  # a maximum of 70% to reflect damper leakage per PNNL
  max_oa_sch_name = "#{snc}maxOASch"
  max_oa_sch = OpenStudio::Model::ScheduleRuleset.new(model)
  max_oa_sch.setName(max_oa_sch_name)
  max_oa_sch.defaultDaySchedule.setName("#{max_oa_sch_name}Default")
  max_oa_sch.defaultDaySchedule.addValue(OpenStudio::Time.new(0, 24, 0, 0), 0.7)
  oa_control.setMaximumFractionofOutdoorAirSchedule(max_oa_sch)

  ems = "

  ! Sensors

  EnergyManagementSystem:Sensor,
    #{snc}OASch,
    #{min_oa_sch_name},         !- Output:Variable or Output:Meter Index Key Name,
    Schedule Value;          !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{zn_name_clean}Temp,
    #{zone_air_node_name},  !- Output:Variable or Output:Meter Index Key Name
    System Node Temperature; !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{snc}OAFlowMass,
    #{oa_node_name}, !- Output:Variable or Output:Meter Index Key Name
    System Node Mass Flow Rate;  !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{snc}HeatingRTF,
    #{htg_coil_name},        !- Output:Variable or Output:Meter Index Key Name
    Heating Coil Runtime Fraction;  !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{snc}RTF,
    #{dx_coil_name}, !- Output:Variable or Output:Meter Index Key Name
    Cooling Coil Runtime Fraction;  !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{snc}SpeedRatio,
    #{dx_coilsys_name},        !- Output:Variable or Output:Meter Index Key Name
    Coil System Compressor Speed Ratio;  !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{snc}DATRqd,
    #{sup_out_node_name},  !- Output:Variable or Output:Meter Index Key Name
    System Node Setpoint Temperature;  !- Output:Variable or Output:Meter Name

  EnergyManagementSystem:Sensor,
    #{snc}EconoStatus,
    #{sn},              !- Output:Variable or Output:Meter Index Key Name
    Air System Outdoor Air Economizer Status;  !- Output:Variable or Output:Meter Name

  ! Internal Variables

  EnergyManagementSystem:InternalVariable,
    #{snc}FanDesignPressure,
    #{fan_name},          !- Internal Data Index Key Name
    Fan Nominal Pressure Rise;  !- Internal Data Type

  EnergyManagementSystem:InternalVariable,
    #{snc}DesignFlowMass,
    #{oa_control_name},!- Internal Data Index Key Name
    Outdoor Air Controller Maximum Mass Flow Rate;  !- Internal Data Type

  EnergyManagementSystem:InternalVariable,
    #{snc}OADesignMass,
    #{oa_control_name},!- Internal Data Index Key Name
    Outdoor Air Controller Minimum Mass Flow Rate;  !- Internal Data Type

  ! Actuators

  EnergyManagementSystem:Actuator,
    #{snc}FanPressure,
    #{fan_name},          !- Actuated Component Unique Name
    Fan,                     !- Actuated Component Type
    Fan Pressure Rise;       !- Actuated Component Control Type

  EnergyManagementSystem:Actuator,
    #{snc}TimestepEconEff,!- Name
    #{max_oa_sch_name},  !- Actuated Component Unique Name
    Schedule:Year,       !- Actuated Component Type
    Schedule Value;          !- Actuated Component Control Type

  EnergyManagementSystem:GlobalVariable,
    #{snc}FanPwrExp,   !- Erl Variable 1 Name
    #{snc}Stg1Spd,      !- Erl Variable 2 Name
    #{snc}Stg2Spd,      !- Erl Variable 3 Name
    #{snc}HeatSpeed,
    #{snc}VenSpeed,
    #{snc}NumberofStages;

  EnergyManagementSystem:Program,
    #{snc}EconomizerCTRLProg,
    SET #{snc}TimestepEconEff = 0.7,
    SET #{snc}MaxE = 0.7,
    SET #{snc}DATRqd = (#{snc}DATRqd*1.8)+32,
    SET OATF = (OATF*1.8)+32,
    SET OAwbF = (OAwbF*1.8)+32,
    IF #{snc}OAFlowMass > (#{snc}OADesignMass*#{snc}OASch),
    SET #{snc}EconoActive = 1,
    ELSE,
    SET #{snc}EconoActive = 0,
    ENDIF,
    SET #{snc}dTNeeded = 75-#{snc}DATRqd,
    SET #{snc}CoolDesdT = ((98*0.15)+(75*(1-0.15)))-55,
    SET #{snc}CoolLoad = #{snc}dTNeeded/ #{snc}CoolDesdT,
    IF #{snc}CoolLoad > 1,
    SET #{snc}CoolLoad = 1,
    ELSEIF #{snc}CoolLoad < 0,
    SET #{snc}CoolLoad = 0,
    ENDIF,
    IF #{snc}EconoActive == 1,
    SET #{snc}Stage = #{snc}NumberofStages,
    IF #{snc}Stage == 2,
    IF #{snc}CoolLoad < 0.6,
    SET #{snc}TimestepEconEff = #{snc}MaxE,
    ELSE,
    SET #{snc}ECOEff = 0-2.18919863612305,
    SET #{snc}ECOEff = #{snc}ECOEff+(0-0.674461284910428*#{snc}CoolLoad),
    SET #{snc}ECOEff = #{snc}ECOEff+(0.000459106275872404*(OATF^2)),
    SET #{snc}ECOEff = #{snc}ECOEff+(0-0.00000484778537945252*(OATF^3)),
    SET #{snc}ECOEff = #{snc}ECOEff+(0.182915713033586*OAwbF),
    SET #{snc}ECOEff = #{snc}ECOEff+(0-0.00382838660261133*(OAwbF^2)),
    SET #{snc}ECOEff = #{snc}ECOEff+(0.0000255567460240583*(OAwbF^3)),
    SET #{snc}TimestepEconEff = #{snc}ECOEff,
    ENDIF,
    ELSE,
    SET #{snc}ECOEff = 2.36337942464462,
    SET #{snc}ECOEff = #{snc}ECOEff+(0-0.409939515512619*#{snc}CoolLoad),
    SET #{snc}ECOEff = #{snc}ECOEff+(0-0.0565205596792225*OAwbF),
    SET #{snc}ECOEff = #{snc}ECOEff+(0-0.0000632612294169389*(OATF^2)),
    SET #{snc}TimestepEconEff = #{snc}ECOEff+(0.000571724868775081*(OAwbF^2)),
    ENDIF,
    IF #{snc}TimestepEconEff > #{snc}MaxE,
    SET #{snc}TimestepEconEff = #{snc}MaxE,
    ELSEIF #{snc}TimestepEconEff < (#{snc}OADesignMass*#{snc}OASch),
    SET #{snc}TimestepEconEff = (#{snc}OADesignMass*#{snc}OASch),
    ENDIF,
    ENDIF;

  EnergyManagementSystem:Program,
    #{snc}SetFanPar,
    IF #{snc}NumberofStages == 1,
    Return,
    ENDIF,
    SET #{snc}FanPwrExp = 2.2,
    SET #{snc}OAFrac = #{snc}OAFlowMass/#{snc}DesignFlowMass,
    IF  #{snc}OAFrac < 0.66,
    SET #{snc}VenSpeed = 0.66,
    SET #{snc}Stg1Spd = 0.66,
    ELSE,
    SET #{snc}VenSpeed = #{snc}OAFrac,
    SET #{snc}Stg1Spd = #{snc}OAFrac,
    ENDIF,
    SET #{snc}Stg2Spd = 1.0,
    SET #{snc}HeatSpeed = 1.0;

  EnergyManagementSystem:Program,
    #{snc}FanControl,
    IF #{snc}NumberofStages == 1,
    Return,
    ENDIF,
    IF #{snc}HeatingRTF > 0,
    SET #{snc}Heating = #{snc}HeatingRTF,
    SET #{snc}Ven = 1-#{snc}HeatingRTF,
    SET #{snc}Eco = 0,
    SET #{snc}Stage1 = 0,
    SET #{snc}Stage2 = 0,
    ELSE,
    SET #{snc}Heating = 0,
    SET #{snc}EcoSpeed = #{snc}VenSpeed,
    IF #{snc}SpeedRatio == 0,
    IF #{snc}RTF > 0,
    SET #{snc}Stage1 = #{snc}RTF,
    SET #{snc}Stage2 = 0,
    SET #{snc}Ven = 1-#{snc}RTF,
    SET #{snc}Eco = 0,
    IF #{snc}OAFlowMass > (#{snc}OADesignMass*#{snc}OASch),
    SET #{snc}Stg1Spd = 1.0,
    ENDIF,
    ELSE,
    SET #{snc}Stage1 = 0,
    SET #{snc}Stage2 = 0,
    IF #{snc}OAFlowMass > (#{snc}OADesignMass*#{snc}OASch),
    SET #{snc}Eco = 1.0,
    SET #{snc}Ven = 0,
    !Calculate the expected discharge air temperature if the system runs at its low speed
    SET #{snc}ExpDAT = #{snc}DATRqd-(1-#{snc}VenSpeed)*#{zn_name_clean}Temp,
    SET #{snc}ExpDAT = #{snc}ExpDAT/#{snc}VenSpeed,
    IF OATF > #{snc}ExpDAT,
    SET #{snc}EcoSpeed = #{snc}Stg2Spd,
    ENDIF,
    ELSE,
    SET #{snc}Eco = 0,
    SET #{snc}Ven = 1.0,
    ENDIF,
    ENDIF,
    ELSE,
    SET #{snc}Stage1 = 1-#{snc}SpeedRatio,
    SET #{snc}Stage2 = #{snc}SpeedRatio,
    SET #{snc}Ven = 0,
    SET #{snc}Eco = 0,
    IF #{snc}OAFlowMass > (#{snc}OADesignMass*#{snc}OASch),
    SET #{snc}Stg1Spd = 1.0,
    ENDIF,
    ENDIF,
    ENDIF,
    ! For each mode, (percent time in mode)*(fanSpeer^PwrExp) is the contribution to weighted fan power over time step
    SET #{snc}FPR = #{snc}Ven*(#{snc}VenSpeed ^ #{snc}FanPwrExp),
    SET #{snc}FPR = #{snc}FPR+#{snc}Eco*(#{snc}EcoSpeed^#{snc}FanPwrExp),
    SET #{snc}FPR1 = #{snc}Stage1*(#{snc}Stg1Spd^#{snc}FanPwrExp),
    SET #{snc}FPR = #{snc}FPR+#{snc}FPR1,
    SET #{snc}FPR2 = #{snc}Stage2*(#{snc}Stg2Spd^#{snc}FanPwrExp),
    SET #{snc}FPR = #{snc}FPR+#{snc}FPR2,
    SET #{snc}FPR3 = #{snc}Heating*(#{snc}HeatSpeed^#{snc}FanPwrExp),
    SET #{snc}FanPwrRatio = #{snc}FPR+ #{snc}FPR3,
    ! system fan power is directly proportional to static pressure, so this change linearly adjusts fan energy for speed control
    SET #{snc}FanPressure = #{snc}FanDesignPressure*#{snc}FanPwrRatio;

  EnergyManagementSystem:Program,
    #{snc}SetNumberofStages,
    SET #{snc}NumberofStages =  #{num_stages};

  EnergyManagementSystem:ProgramCallingManager,
    #{snc}SetNumberofStagesCallingManager,
    BeginNewEnvironment,
    #{snc}SetNumberofStages;  !- Program Name 1

  EnergyManagementSystem:ProgramCallingManager,
    #{snc}ECOManager,
    InsideHVACSystemIterationLoop,  !- EnergyPlus Model Calling Point
    #{snc}EconomizerCTRLProg;  !- Program Name 1

  EnergyManagementSystem:ProgramCallingManager,
    #{snc}FanParametermanager,
    BeginNewEnvironment,
    #{snc}SetFanPar;

  EnergyManagementSystem:ProgramCallingManager,
    #{snc}FanMainManager,
    BeginTimestepBeforePredictor,
    #{snc}FanControl;

  "

  # Write the ems out
  # File.open("#{Dir.pwd}/#{snc}_ems.idf", 'w') do |file|
  # file.puts ems
  # end

  return ems
end

#apply_standard_controls(template, climate_zone) ⇒ Bool

TODO:

optimum start

TODO:

night damper shutoff

TODO:

nightcycle control

TODO:

night fan shutoff

Apply all standard required controls to the airloop

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 44

def apply_standard_controls(template, climate_zone)
  # Energy Recovery Ventilation
  if energy_recovery_ventilator_required?(template, climate_zone)
    apply_energy_recovery_ventilator(template)
  end

  # Economizers
  apply_economizer_limits(template, climate_zone)
  apply_economizer_integration(template, climate_zone)

  # Multizone VAV Systems
  if multizone_vav_system?

    # VAV Reheat Control
    apply_vav_damper_action(template)

    # Multizone VAV Optimization
    # This rule does not apply to two hospital and one outpatient systems (TODO add hospital two systems as exception)
    unless name.to_s.include? 'Outpatient F1'
      if multizone_vav_optimization_required?(template, climate_zone)
        enable_multizone_vav_optimization
      else
        disable_multizone_vav_optimization
      end
    end

    # Static Pressure Reset
    # assume no systems have DDC control of VAV terminals
    has_ddc = false
    spr_req = static_pressure_reset_required?(template, has_ddc)
    supply_return_exhaust_relief_fans.each do |fan|
      if fan.to_FanVariableVolume.is_initialized
        plr_req = fan.part_load_fan_power_limitation?(template)
        # Part Load Fan Pressure Control & Static Pressure Reset
        if plr_req && spr_req
          fan.set_control_type('Multi Zone VAV with VSD and Static Pressure Reset')
        # Part Load Fan Pressure Control only
        elsif plr_req && !spr_req
          fan.set_control_type('Multi Zone VAV with VSD and Fixed SP Setpoint')
        # Static Pressure Reset only
        elsif !plr_req && spr_req
          fan.set_control_type('Multi Zone VAV with VSD and Fixed SP Setpoint')
        # No Control Required
        else
          fan.set_control_type('Multi Zone VAV with AF or BI Riding Curve')
        end
      else
        OpenStudio.logFree(OpenStudio::Error, 'openstudio.standards.AirLoopHVAC', "For #{name}: there is a constant volume fan on a multizone vav system.  Cannot apply static pressure reset controls.")
      end
    end

  end

  # Single zone systems
  if self.thermalZones.size == 1
    supply_return_exhaust_relief_fans.each do |fan|
      if fan.to_FanVariableVolume.is_initialized
        fan.set_control_type('Single Zone VAV Fan')
      end
    end
  # self.apply_single_zone_controls(template, climate_zone)
  end

  # DCV
  if demand_control_ventilation_required?(template, climate_zone)
    enable_demand_control_ventilation(template, climate_zone)
  end

  # SAT reset
  # TODO Prototype buildings use OAT-based SAT reset,
  # but PRM RM suggests Warmest zone based SAT reset.
  if supply_air_temperature_reset_required?(template, climate_zone)
    enable_supply_air_temperature_reset_warmest_zone(template)
  end

  # Unoccupied shutdown
  if unoccupied_fan_shutoff_required?(template)
    enable_unoccupied_fan_shutoff
  else
    setAvailabilitySchedule(model.alwaysOnDiscreteSchedule)
  end

  # Motorized OA damper
  if motorized_oa_damper_required?(template, climate_zone)
    # Assume that the availability schedule has already been
    # set to reflect occupancy and use this for the OA damper.
    add_motorized_oa_damper(0.15, availabilitySchedule)
  else
    remove_motorized_oa_damper
  end

  # TODO: Optimum Start
  # for systems exceeding 10,000 cfm
  # Don't think that OS will be able to do this.
  # OS currently only allows 1 availability manager
  # at a time on an AirLoopHVAC.  If we add an
  # AvailabilityManager:OptimumStart, it
  # will replace the AvailabilityManager:NightCycle.
end

#apply_vav_damper_action(template) ⇒ Bool

TODO:

see if this impacts the sizing run.

Set the VAV damper control to single maximum or dual maximum control depending on the standard.

Returns:

  • (Bool) —

    Returns true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2610

def apply_vav_damper_action(template)
  damper_action = nil
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004'
    damper_action = 'Single Maximum'
  when '90.1-2007', '90.1-2010', '90.1-2013', 'NECB 2011'
    damper_action = 'Dual Maximum'
  end

  # Interpret this as an EnergyPlus input
  damper_action_eplus = nil
  if damper_action == 'Single Maximum'
    damper_action_eplus = 'Normal'
  elsif damper_action == 'Dual Maximum'
    damper_action_eplus = 'Reverse'
  end

  # Set the control for any VAV reheat terminals
  # on this airloop.
  control_type_set = false
  demandComponents.each do |equip|
    if equip.to_AirTerminalSingleDuctVAVReheat.is_initialized
      term = equip.to_AirTerminalSingleDuctVAVReheat.get
      # Dual maximum only applies to terminals with HW reheat coils
      if damper_action == 'Dual Maximum'
        if term.reheatCoil.to_CoilHeatingWater.is_initialized
          term.setDamperHeatingAction(damper_action_eplus)
          control_type_set = true
        end
      else
        term.setDamperHeatingAction(damper_action_eplus)
        control_type_set = true
      end
    end
  end

  if control_type_set
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: VAV damper action was set to #{damper_action} control.")
  end

  return true
end

#applySizingValues ⇒ Object

Takes the values calculated by the EnergyPlus sizing routines and puts them into this object model in place of the autosized fields. Must have previously completed a run with sql output for this to work.



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# File 'lib/openstudio-standards/hvac_sizing/Siz.AirLoopHVAC.rb', line 13

def applySizingValues

  design_supply_air_flow_rate = self.autosizedDesignSupplyAirFlowRate
  if design_supply_air_flow_rate.is_initialized
    self.setDesignSupplyAirFlowRate(design_supply_air_flow_rate.get) 
  end
      
end

#autosize ⇒ Object

Sets all auto-sizeable fields to autosize



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# File 'lib/openstudio-standards/hvac_sizing/Siz.AirLoopHVAC.rb', line 6

def autosize
  self.autosizeDesignSupplyAirFlowRate
end

#autosizedDesignSupplyAirFlowRate ⇒ Object

returns the autosized design supply air flow rate as an optional double



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# File 'lib/openstudio-standards/hvac_sizing/Siz.AirLoopHVAC.rb', line 23

def autosizedDesignSupplyAirFlowRate

  return self.model.getAutosizedValue(self, 'Design Supply Air Flow Rate', 'm3/s')
  
end

#data_center_area_served ⇒ Double

TODO:

Add an is_data_center field to the

Determine how much data center area the airloop serves.

in m^2. standards space type spreadsheet instead of relying on the standards space type name to identify a data center.

Returns:

  • (Double) —

    the area of data center is served,



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3576

def data_center_area_served
  dc_area_m2 = 0.0

  thermalZones.each do |zone|
    zone.spaces.each do |space|
      # Skip spaces with no space type
      next if space.spaceType.empty?
      space_type = space.spaceType.get
      next if space_type.standardsSpaceType.empty?
      standards_space_type = space_type.standardsSpaceType.get
      # Counts as a data center if the name includes 'data'
      next unless standards_space_type.downcase.include?('data')
      dc_area_m2 += space.floorArea
    end
  end

  return dc_area_m2
end

#demand_control_ventilation_required?(template, climate_zone) ⇒ Bool

TODO:

Add exception logic for systems that serve multifamily, parking garage, warehouse

Determine if demand control ventilation (DCV) is required for this air loop.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2253

def demand_control_ventilation_required?(template, climate_zone)
  dcv_required = false

  # Not required by the old vintages
  if template == 'DOE Ref Pre-1980' || template == 'DOE Ref 1980-2004' || template == 'NECB 2011'
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{template} #{climate_zone}:  #{name}: DCV is not required for any system.")
    return dcv_required
  end

  # Not required for systems that require an ERV
  if energy_recovery?
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: DCV is not required since the system has Energy Recovery.")
    return dcv_required
  end

  # OA flow limits
  min_oa_without_economizer_cfm = 0
  min_oa_with_economizer_cfm = 0
  case template
  when '90.1-2004'
    min_oa_without_economizer_cfm = 3000
    min_oa_with_economizer_cfm = 0
  when '90.1-2007', '90.1-2010'
    min_oa_without_economizer_cfm = 3000
    min_oa_with_economizer_cfm = 1200
  when '90.1-2013'
    min_oa_without_economizer_cfm = 3000
    min_oa_with_economizer_cfm = 750
  end

  # Get the min OA flow rate
  oa_flow_m3_per_s = 0
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
    controller_oa = oa_system.getControllerOutdoorAir
    if controller_oa.minimumOutdoorAirFlowRate.is_initialized
      oa_flow_m3_per_s = controller_oa.minimumOutdoorAirFlowRate.get
    elsif controller_oa.autosizedMinimumOutdoorAirFlowRate.is_initialized
      oa_flow_m3_per_s = controller_oa.autosizedMinimumOutdoorAirFlowRate.get
    end
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, DCV not applicable because it has no OA intake.")
    return dcv_required
  end
  oa_flow_cfm = OpenStudio.convert(oa_flow_m3_per_s, 'm^3/s', 'cfm').get

  # Check for min OA without an economizer OR has economizer
  if oa_flow_cfm < min_oa_without_economizer_cfm && economizer? == false
    # Message if doesn't pass OA limit
    if oa_flow_cfm < min_oa_without_economizer_cfm
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: DCV is not required since the system min oa flow is #{oa_flow_cfm.round} cfm, less than the minimum of #{min_oa_without_economizer_cfm.round} cfm.")
    end
    # Message if doesn't have economizer
    if economizer? == false
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: DCV is not required since the system does not have an economizer.")
    end
    return dcv_required
  end

  # If has economizer, cfm limit is lower
  if oa_flow_cfm < min_oa_with_economizer_cfm && economizer?
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: DCV is not required since the system has an economizer, but the min oa flow is #{oa_flow_cfm.round} cfm, less than the minimum of #{min_oa_with_economizer_cfm.round} cfm for systems with an economizer.")
    return dcv_required
  end

  # Check area and density limits
  # for all of zones on the loop
  any_zones_req_dcv = false
  thermalZones.sort.each do |zone|
    if zone.demand_control_ventilation_required?(template, climate_zone)
      any_zones_req_dcv = true
      break
    end
  end
  unless any_zones_req_dcv
    return dcv_required
  end

  # If here, DCV is required
  dcv_required = true

  return dcv_required
end

#disable_multizone_vav_optimization ⇒ Bool

Disable multizone vav optimization by changing the Outdoor Air Method in the Controller:MechanicalVentilation object to ‘ZoneSum’

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1982

def disable_multizone_vav_optimization
  # Disable multizone vav optimization
  # at each timestep.
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
    controller_oa = oa_system.getControllerOutdoorAir
    controller_mv = controller_oa.controllerMechanicalVentilation
    controller_mv.setSystemOutdoorAirMethod('ZoneSum')
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}, cannot disable multizone vav optimization because the system has no OA intake.")
    return false
  end
end

#economizer? ⇒ Bool

Determine if the system has an economizer

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2515

def economizer?
  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir
  economizer_type = oa_control.getEconomizerControlType

  # Return false if no economizer is present
  if economizer_type == 'NoEconomizer'
    return false
  else
    return true
  end
end

#economizer_required?(template, climate_zone) ⇒ Bool

Determine whether or not this system is required to have an economizer.

‘ASHRAE 169-2006-3A’, ‘ASHRAE 169-2006-3B’, ‘ASHRAE 169-2006-3C’, ‘ASHRAE 169-2006-4A’, ‘ASHRAE 169-2006-4B’, ‘ASHRAE 169-2006-4C’, ‘ASHRAE 169-2006-5A’, ‘ASHRAE 169-2006-5B’, ‘ASHRAE 169-2006-5C’, ‘ASHRAE 169-2006-6A’, ‘ASHRAE 169-2006-6B’, ‘ASHRAE 169-2006-7A’, ‘ASHRAE 169-2006-7B’, ‘ASHRAE 169-2006-8A’, ‘ASHRAE 169-2006-8B’

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if an economizer is required, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 674

def economizer_required?(template, climate_zone)
  economizer_required = false

  return economizer_required if name.to_s.include? 'Outpatient F1'

  # A big number of btu per hr as the minimum requirement
  infinity_btu_per_hr = 999_999_999_999
  minimum_capacity_btu_per_hr = infinity_btu_per_hr

  # Determine if the airloop serves any computer rooms
  # / data centers, which changes the economizer.
  is_dc = false
  if data_center_area_served > 0
    is_dc = true
  end

  # Determine the minimum capacity that requires an economizer
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007'
    case climate_zone
    when 'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-4A'
      minimum_capacity_btu_per_hr = infinity_btu_per_hr # No requirement
    when 'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-5A',
        'ASHRAE 169-2006-6A',
        'ASHRAE 169-2006-7A',
        'ASHRAE 169-2006-7B',
        'ASHRAE 169-2006-8A',
        'ASHRAE 169-2006-8B'
      minimum_capacity_btu_per_hr = 35_000
    when 'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
        'ASHRAE 169-2006-4B',
        'ASHRAE 169-2006-4C',
        'ASHRAE 169-2006-5B',
        'ASHRAE 169-2006-5C',
        'ASHRAE 169-2006-6B'
      minimum_capacity_btu_per_hr = 65_000
    end
  when '90.1-2010', '90.1-2013'
    if is_dc # data center / computer room
      case climate_zone
      when 'ASHRAE 169-2006-1A',
          'ASHRAE 169-2006-1B',
          'ASHRAE 169-2006-2A',
          'ASHRAE 169-2006-3A',
          'ASHRAE 169-2006-4A'
        minimum_capacity_btu_per_hr = infinity_btu_per_hr # No requirement
      when 'ASHRAE 169-2006-2B',
          'ASHRAE 169-2006-5A',
          'ASHRAE 169-2006-6A',
          'ASHRAE 169-2006-7A',
          'ASHRAE 169-2006-7B',
          'ASHRAE 169-2006-8A',
          'ASHRAE 169-2006-8B'
        minimum_capacity_btu_per_hr = 135_000
      when 'ASHRAE 169-2006-3B',
          'ASHRAE 169-2006-3C',
          'ASHRAE 169-2006-4B',
          'ASHRAE 169-2006-4C',
          'ASHRAE 169-2006-5B',
          'ASHRAE 169-2006-5C',
          'ASHRAE 169-2006-6B'
        minimum_capacity_btu_per_hr = 65_000
      end
    else
      case climate_zone
      when 'ASHRAE 169-2006-1A',
          'ASHRAE 169-2006-1B'
        minimum_capacity_btu_per_hr = infinity_btu_per_hr # No requirement
      when 'ASHRAE 169-2006-2A',
          'ASHRAE 169-2006-3A',
          'ASHRAE 169-2006-4A',
          'ASHRAE 169-2006-2B',
          'ASHRAE 169-2006-5A',
          'ASHRAE 169-2006-6A',
          'ASHRAE 169-2006-7A',
          'ASHRAE 169-2006-7B',
          'ASHRAE 169-2006-8A',
          'ASHRAE 169-2006-8B',
          'ASHRAE 169-2006-3B',
          'ASHRAE 169-2006-3C',
          'ASHRAE 169-2006-4B',
          'ASHRAE 169-2006-4C',
          'ASHRAE 169-2006-5B',
          'ASHRAE 169-2006-5C',
          'ASHRAE 169-2006-6B'
        minimum_capacity_btu_per_hr = 54_000
      end
    end
  when 'NECB 2011'
    minimum_capacity_btu_per_hr = 68_243 # NECB requires economizer for cooling cap > 20 kW
  end

  # Check whether the system requires an economizer by comparing
  # the system capacity to the minimum capacity.
  total_cooling_capacity_w = total_cooling_capacity
  total_cooling_capacity_btu_per_hr = OpenStudio.convert(total_cooling_capacity_w, 'W', 'Btu/hr').get
  if total_cooling_capacity_btu_per_hr >= minimum_capacity_btu_per_hr
    if is_dc
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "#{name} requires an economizer because the total cooling capacity of #{total_cooling_capacity_btu_per_hr.round} Btu/hr exceeds the minimum capacity of #{minimum_capacity_btu_per_hr.round} Btu/hr for data centers.")
    else
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "#{name} requires an economizer because the total cooling capacity of #{total_cooling_capacity_btu_per_hr.round} Btu/hr exceeds the minimum capacity of #{minimum_capacity_btu_per_hr.round} Btu/hr.")
    end
    economizer_required = true
  else
    if is_dc
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "#{name} does not require an economizer because the total cooling capacity of #{total_cooling_capacity_btu_per_hr.round} Btu/hr is less than the minimum capacity of #{minimum_capacity_btu_per_hr.round} Btu/hr for data centers.")
    else
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "#{name} does not require an economizer because the total cooling capacity of #{total_cooling_capacity_btu_per_hr.round} Btu/hr is less than the minimum capacity of #{minimum_capacity_btu_per_hr.round} Btu/hr.")
    end
  end

  return economizer_required
end

#economizer_type_allowable?(template, climate_zone) ⇒ Bool

Check the economizer type currently specified in the ControllerOutdoorAir object on this air loop is acceptable per the standard.

Returns false if the economizer type is not allowable.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if allowable, if the system has no economizer or no OA system.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1244

def economizer_type_allowable?(template, climate_zone)
  # EnergyPlus economizer types
  # 'NoEconomizer'
  # 'FixedDryBulb'
  # 'FixedEnthalpy'
  # 'DifferentialDryBulb'
  # 'DifferentialEnthalpy'
  # 'FixedDewPointAndDryBulb'
  # 'ElectronicEnthalpy'
  # 'DifferentialDryBulbAndEnthalpy'

  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return true # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir
  economizer_type = oa_control.getEconomizerControlType

  # Return true if no economizer is present
  if economizer_type == 'NoEconomizer'
    return true
  end

  # Determine the minimum capacity that requires an economizer
  prohibited_types = []
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007'
    case climate_zone
    when 'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
        'ASHRAE 169-2006-4B',
        'ASHRAE 169-2006-4C',
        'ASHRAE 169-2006-5B',
        'ASHRAE 169-2006-6B',
        'ASHRAE 169-2006-7A',
        'ASHRAE 169-2006-7B',
        'ASHRAE 169-2006-8A',
        'ASHRAE 169-2006-8B'
      prohibited_types = ['FixedEnthalpy']
    when
      'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-4A'
      prohibited_types = ['DifferentialDryBulb']
    when
      'ASHRAE 169-2006-5A',
        'ASHRAE 169-2006-6A',
        prohibited_types = []
    end
  when '90.1-2010', '90.1-2013'
    case climate_zone
    when 'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
        'ASHRAE 169-2006-4B',
        'ASHRAE 169-2006-4C',
        'ASHRAE 169-2006-5B',
        'ASHRAE 169-2006-6B',
        'ASHRAE 169-2006-7A',
        'ASHRAE 169-2006-7B',
        'ASHRAE 169-2006-8A',
        'ASHRAE 169-2006-8B'
      prohibited_types = ['FixedEnthalpy']
    when
      'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-4A'
      prohibited_types = ['FixedDryBulb', 'DifferentialDryBulb']
    when
      'ASHRAE 169-2006-5A',
        'ASHRAE 169-2006-6A',
        prohibited_types = []
    end
  end

  # Check if the specified type is allowed
  economizer_type_allowed = true
  if prohibited_types.include?(economizer_type)
    economizer_type_allowed = false
  end

  return economizer_type_allowed
end

#enable_demand_control_ventilation(template, climate_zone) ⇒ Bool

Enable demand control ventilation (DCV) for this air loop. Zones on this loop that require DCV preserve both per-area and per-person OA reqs. Other zones have OA reqs converted to per-area values only so that DCV won’t impact these zones.

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2344

def enable_demand_control_ventilation(template, climate_zone)
  # Get the OA intake
  controller_oa = nil
  controller_mv = nil
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
    controller_oa = oa_system.getControllerOutdoorAir
    controller_mv = controller_oa.controllerMechanicalVentilation
    if controller_mv.demandControlledVentilation == true
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: DCV was already enabled.")
      return true
    end
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}: Could not enable DCV since the system has no OA intake.")
    return false
  end

  # Change the min flow rate in the controller outdoor air
  controller_oa.setMinimumOutdoorAirFlowRate(0.0)

  # Enable DCV in the controller mechanical ventilation
  controller_mv.setDemandControlledVentilation(true)

  # Zones that require DCV preserve
  # both per-area and per-person OA reqs.
  # Other zones have OA reqs converted
  # to per-area values only so that DCV
  thermalZones.sort.each do |zone|
    if zone.demand_control_ventilation_required?(template, climate_zone)
      zone.convert_oa_req_to_per_area
    end
  end

  return true
end

#enable_multizone_vav_optimization ⇒ Bool

Enable multizone vav optimization by changing the Outdoor Air Method in the Controller:MechanicalVentilation object to ‘VentilationRateProcedure’

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1964

def enable_multizone_vav_optimization
  # Enable multizone vav optimization
  # at each timestep.
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
    controller_oa = oa_system.getControllerOutdoorAir
    controller_mv = controller_oa.controllerMechanicalVentilation
    controller_mv.setSystemOutdoorAirMethod('VentilationRateProcedure')
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}, cannot enable multizone vav optimization because the system has no OA intake.")
    return false
  end
end

#enable_supply_air_temperature_reset_outdoor_temperature ⇒ Bool

Enable supply air temperature (SAT) reset based on outdoor air conditions. SAT will be kept at the current design temperature when outdoor air is above 70F, increased by 5F when outdoor air is below 50F, and reset linearly when outdoor air is between 50F and 70F.

Returns:

  • (Bool) —

    Returns true if successful, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2473

def enable_supply_air_temperature_reset_outdoor_temperature
  # for AHU1 in Outpatient, SAT is 52F constant, no reset
  return true if name.get == 'PVAV Outpatient F1'

  # Get the current setpoint and calculate
  # the new setpoint.
  sizing_system = sizingSystem
  sat_at_hi_oat_c = sizing_system.centralCoolingDesignSupplyAirTemperature
  sat_at_hi_oat_f = OpenStudio.convert(sat_at_hi_oat_c, 'C', 'F').get
  # 5F increase when it's cold outside,
  # and therefore less cooling capacity is likely required.
  increase_f = 5.0
  sat_at_lo_oat_f = sat_at_hi_oat_f + increase_f
  sat_at_lo_oat_c = OpenStudio.convert(sat_at_lo_oat_f, 'F', 'C').get

  # Define the high and low outdoor air temperatures
  lo_oat_f = 50
  lo_oat_c = OpenStudio.convert(lo_oat_f, 'F', 'C').get
  hi_oat_f = 70
  hi_oat_c = OpenStudio.convert(hi_oat_f, 'F', 'C').get

  # Create a setpoint manager
  sat_oa_reset = OpenStudio::Model::SetpointManagerOutdoorAirReset.new(model)
  sat_oa_reset.setName("#{name} SAT Reset")
  sat_oa_reset.setControlVariable('Temperature')
  sat_oa_reset.setSetpointatOutdoorLowTemperature(sat_at_lo_oat_c)
  sat_oa_reset.setOutdoorLowTemperature(lo_oat_c)
  sat_oa_reset.setSetpointatOutdoorHighTemperature(sat_at_hi_oat_c)
  sat_oa_reset.setOutdoorHighTemperature(hi_oat_c)

  # Attach the setpoint manager to the
  # supply outlet node of the system.
  sat_oa_reset.addToNode(supplyOutletNode)

  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Supply air temperature reset was enabled.  When OAT > #{hi_oat_f.round}F, SAT is #{sat_at_hi_oat_f.round}F.  When OAT < #{lo_oat_f.round}F, SAT is #{sat_at_lo_oat_f.round}F.  It varies linearly in between these points.")

  return true
end

#enable_supply_air_temperature_reset_warmest_zone(template) ⇒ Bool

Enable supply air temperature (SAT) reset based on the cooling demand of the warmest zone.

Parameters:

  • template (String) —

    valid choices: ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

Returns:

  • (Bool) —

    Returns true if successful, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2429

def enable_supply_air_temperature_reset_warmest_zone(template)
  # Get the current setpoint and calculate
  # the new setpoint.
  sizing_system = sizingSystem
  design_sat_c = sizing_system.centralCoolingDesignSupplyAirTemperature
  design_sat_f = OpenStudio.convert(design_sat_c, 'C', 'F').get

  case template
  when '90.1-2004'
    # 2004 has a 10F sat reset
    sat_reset_r = 10
  when '90.1-2007', '90.1-2010', '90.1-2013'
    sat_reset_r = 5
  end

  sat_reset_k = OpenStudio.convert(sat_reset_r, 'R', 'K').get

  max_sat_f = design_sat_f + sat_reset_r
  max_sat_c = design_sat_c + sat_reset_k

  # Create a setpoint manager
  sat_warmest_reset = OpenStudio::Model::SetpointManagerWarmest.new(model)
  sat_warmest_reset.setName("#{name} SAT Warmest Reset")
  sat_warmest_reset.setStrategy('MaximumTemperature')
  sat_warmest_reset.setMinimumSetpointTemperature(design_sat_c)
  sat_warmest_reset.setMaximumSetpointTemperature(max_sat_c)

  # Attach the setpoint manager to the
  # supply outlet node of the system.
  sat_warmest_reset.addToNode(supplyOutletNode)

  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Supply air temperature reset was enabled using a SPM Warmest with a min SAT of #{design_sat_f.round}F and a max SAT of #{max_sat_f.round}F.")

  return true
end

#enable_unoccupied_fan_shutoff(min_occ_pct = 0.15) ⇒ Bool

Shut off the system during unoccupied periods. During these times, systems will cycle on briefly if temperature drifts below setpoint. For systems with fan-powered terminals, only the terminal fans will cycle on. If the system already has a schedule other than Always-On, no change will be made. If the system has an Always-On schedule assigned, a new schedule will be created. In this case, occupied is defined as the total percent occupancy for the loop for all zones served.

the system will be considered unoccupied.

Parameters:

  • min_occ_pct (Double) (defaults to: 0.15) —

    the fractional value below which

Returns:

  • (Bool) —

    true if successful, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3474

def enable_unoccupied_fan_shutoff(min_occ_pct = 0.15)
  # Set the system to night cycle
  night_cycle_type = 'CycleOnAny'
  # For VAV with PFP boxes, cycle zone fans only
  unless demandComponents('OS:AirTerminal:SingleDuct:ParallelPIU:Reheat'.to_IddObjectType).empty?
    night_cycle_type = 'CycleOnAnyZoneFansOnly'
  end
  setNightCycleControlType(night_cycle_type)

  # Check if already using a schedule other than always on
  avail_sch = availabilitySchedule
  unless avail_sch == model.alwaysOnDiscreteSchedule
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Availability schedule is already set to #{avail_sch.name}.  Will assume this includes unoccupied shut down; no changes will be made.")
    return true
  end

  # Get the airloop occupancy schedule
  loop_occ_sch = get_occupancy_schedule(min_occ_pct)
  flh = loop_occ_sch.annual_equivalent_full_load_hrs
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Annual occupied hours = #{flh.round} hr/yr, assuming a #{min_occ_pct} occupancy threshold.  This schedule will be used as the HVAC operation schedule.")

  # Set HVAC availability schedule to follow occupancy
  setAvailabilitySchedule(loop_occ_sch)

  return true
end

#energy_recovery? ⇒ Bool

Determine if the system has energy recovery already

Returns:

  • (Bool) —

    Returns true if an ERV is present, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2584

def energy_recovery?
  has_erv = false

  # Get the OA system
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return has_erv # No OA system
  end

  # Find any ERV on the OA system
  oa_sys.oaComponents.each do |oa_comp|
    if oa_comp.to_HeatExchangerAirToAirSensibleAndLatent.is_initialized
      has_erv = true
    end
  end

  return has_erv
end

#energy_recovery_ventilator_required?(template, climate_zone) ⇒ Bool

TODO:

Add exception logic for systems serving parking garage, warehouse, or multifamily

Check if ERV is required on this airloop.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1341

def energy_recovery_ventilator_required?(template, climate_zone)
  # ERV Not Applicable for AHUs that serve
  # parking garage, warehouse, or multifamily
  # if space_types_served_names.include?('PNNL_Asset_Rating_Apartment_Space_Type') ||
  # space_types_served_names.include?('PNNL_Asset_Rating_LowRiseApartment_Space_Type') ||
  # space_types_served_names.include?('PNNL_Asset_Rating_ParkingGarage_Space_Type') ||
  # space_types_served_names.include?('PNNL_Asset_Rating_Warehouse_Space_Type')
  # OpenStudio::logFree(OpenStudio::Info, "openstudio.standards.AirLoopHVAC", "For #{self.name}, ERV not applicable because it because it serves parking garage, warehouse, or multifamily.")
  # return false
  # end

  erv_required = nil
  # ERV not applicable for medical AHUs (AHU1 in Outpatient), per AIA 2001 - 7.31.D2.
  if name.to_s.include? 'Outpatient F1'
    erv_required = false
    return erv_required
  end

  # ERV not applicable for medical AHUs, per AIA 2001 - 7.31.D2.
  if name.to_s.include? 'VAV_ER'
    erv_required = false
    return erv_required
  elsif name.to_s.include? 'VAV_OR'
    erv_required = false
    return erv_required
  end
  case template
  when '90.1-2004', '90.1-2007'
    if name.to_s.include? 'VAV_ICU'
      erv_required = false
      return erv_required
    elsif name.to_s.include? 'VAV_PATRMS'
      erv_required = false
      return erv_required
    end
  end

  # ERV Not Applicable for AHUs that have DCV
  # or that have no OA intake.
  controller_oa = nil
  controller_mv = nil
  oa_system = nil
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
    controller_oa = oa_system.getControllerOutdoorAir
    controller_mv = controller_oa.controllerMechanicalVentilation
    if controller_mv.demandControlledVentilation == true
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV not applicable because DCV enabled.")
      return false
    end
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV not applicable because it has no OA intake.")
    return false
  end

  # Get the AHU design supply air flow rate
  dsn_flow_m3_per_s = nil
  if designSupplyAirFlowRate.is_initialized
    dsn_flow_m3_per_s = designSupplyAirFlowRate.get
  elsif autosizedDesignSupplyAirFlowRate.is_initialized
    dsn_flow_m3_per_s = autosizedDesignSupplyAirFlowRate.get
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} design supply air flow rate is not available, cannot apply efficiency standard.")
    return false
  end
  dsn_flow_cfm = OpenStudio.convert(dsn_flow_m3_per_s, 'm^3/s', 'cfm').get

  # Get the minimum OA flow rate
  min_oa_flow_m3_per_s = nil
  if controller_oa.minimumOutdoorAirFlowRate.is_initialized
    min_oa_flow_m3_per_s = controller_oa.minimumOutdoorAirFlowRate.get
  elsif controller_oa.autosizedMinimumOutdoorAirFlowRate.is_initialized
    min_oa_flow_m3_per_s = controller_oa.autosizedMinimumOutdoorAirFlowRate.get
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{controller_oa.name}: minimum OA flow rate is not available, cannot apply efficiency standard.")
    return false
  end
  min_oa_flow_cfm = OpenStudio.convert(min_oa_flow_m3_per_s, 'm^3/s', 'cfm').get

  # Calculate the percent OA at design airflow
  pct_oa = min_oa_flow_m3_per_s / dsn_flow_m3_per_s

  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004'
    erv_cfm = nil # Not required
  when '90.1-2004', '90.1-2007'
    erv_cfm = if pct_oa < 0.7
                nil
              else
                # @Todo: Add exceptions (eg: e. cooling systems in climate zones 3C, 4C, 5B, 5C, 6B, 7 and 8 | d. Heating systems in climate zones 1 to 3)
                5000
              end
  when '90.1-2010'
    # Table 6.5.6.1
    case climate_zone
    when 'ASHRAE 169-2006-3B', 'ASHRAE 169-2006-3C', 'ASHRAE 169-2006-4B', 'ASHRAE 169-2006-4C', 'ASHRAE 169-2006-5B'
      if pct_oa < 0.3
        erv_cfm = nil
      elsif pct_oa >= 0.3 && pct_oa < 0.4
        erv_cfm = nil
      elsif pct_oa >= 0.4 && pct_oa < 0.5
        erv_cfm = nil
      elsif pct_oa >= 0.5 && pct_oa < 0.6
        erv_cfm = nil
      elsif pct_oa >= 0.6 && pct_oa < 0.7
        erv_cfm = nil
      elsif pct_oa >= 0.7 && pct_oa < 0.8
        erv_cfm = 5000
      elsif pct_oa >= 0.8
        erv_cfm = 5000
      end
    when 'ASHRAE 169-2006-1B', 'ASHRAE 169-2006-2B', 'ASHRAE 169-2006-5C'
      if pct_oa < 0.3
        erv_cfm = nil
      elsif pct_oa >= 0.3 && pct_oa < 0.4
        erv_cfm = nil
      elsif pct_oa >= 0.4 && pct_oa < 0.5
        erv_cfm = nil
      elsif pct_oa >= 0.5 && pct_oa < 0.6
        erv_cfm = 26_000
      elsif pct_oa >= 0.6 && pct_oa < 0.7
        erv_cfm = 12_000
      elsif pct_oa >= 0.7 && pct_oa < 0.8
        erv_cfm = 5000
      elsif pct_oa >= 0.8
        erv_cfm = 4000
      end
    when 'ASHRAE 169-2006-6B'
      if pct_oa < 0.3
        erv_cfm = nil
      elsif pct_oa >= 0.3 && pct_oa < 0.4
        erv_cfm = 11_000
      elsif pct_oa >= 0.4 && pct_oa < 0.5
        erv_cfm = 5500
      elsif pct_oa >= 0.5 && pct_oa < 0.6
        erv_cfm = 4500
      elsif pct_oa >= 0.6 && pct_oa < 0.7
        erv_cfm = 3500
      elsif pct_oa >= 0.7 && pct_oa < 0.8
        erv_cfm = 2500
      elsif pct_oa >= 0.8
        erv_cfm = 1500
      end
    when 'ASHRAE 169-2006-1A', 'ASHRAE 169-2006-2A', 'ASHRAE 169-2006-3A', 'ASHRAE 169-2006-4A', 'ASHRAE 169-2006-5A', 'ASHRAE 169-2006-6A'
      if pct_oa < 0.3
        erv_cfm = nil
      elsif pct_oa >= 0.3 && pct_oa < 0.4
        erv_cfm = 5500
      elsif pct_oa >= 0.4 && pct_oa < 0.5
        erv_cfm = 4500
      elsif pct_oa >= 0.5 && pct_oa < 0.6
        erv_cfm = 3500
      elsif pct_oa >= 0.6 && pct_oa < 0.7
        erv_cfm = 2000
      elsif pct_oa >= 0.7 && pct_oa < 0.8
        erv_cfm = 1000
      elsif pct_oa >= 0.8
        erv_cfm = 0
      end
    when 'ASHRAE 169-2006-7A', 'ASHRAE 169-2006-7B', 'ASHRAE 169-2006-8A', 'ASHRAE 169-2006-8B'
      if pct_oa < 0.3
        erv_cfm = nil
      elsif pct_oa >= 0.3 && pct_oa < 0.4
        erv_cfm = 2500
      elsif pct_oa >= 0.4 && pct_oa < 0.5
        erv_cfm = 1000
      elsif pct_oa >= 0.5 && pct_oa < 0.6
        erv_cfm = 0
      elsif pct_oa >= 0.6 && pct_oa < 0.7
        erv_cfm = 0
      elsif pct_oa >= 0.7 && pct_oa < 0.8
        erv_cfm = 0
      elsif pct_oa >= 0.8
        erv_cfm = 0
      end
    end
  when '90.1-2013'
    # Calculate the number of system operating hours
    # based on the availability schedule.
    ann_op_hrs = 0.0
    avail_sch = availabilitySchedule
    if avail_sch == model.alwaysOnDiscreteSchedule
      ann_op_hrs = 8760.0
    elsif avail_sch.to_ScheduleRuleset.is_initialized
      avail_sch = avail_sch.to_ScheduleRuleset.get
      ann_op_hrs = avail_sch.annual_hours_above_value(0.0)
    else
      OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}: could not determine annual operating hours. Assuming less than 8,000 for ERV determination.")
    end

    if ann_op_hrs < 8000.0
      # Table 6.5.6.1-1, less than 8000 hrs
      case climate_zone
      when 'ASHRAE 169-2006-3B', 'ASHRAE 169-2006-3C', 'ASHRAE 169-2006-4B', 'ASHRAE 169-2006-4C', 'ASHRAE 169-2006-5B'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = nil
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = nil
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = nil
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = nil
        elsif pct_oa >= 0.5 && pct_oa < 0.6
          erv_cfm = nil
        elsif pct_oa >= 0.6 && pct_oa < 0.7
          erv_cfm = nil
        elsif pct_oa >= 0.7 && pct_oa < 0.8
          erv_cfm = nil
        elsif pct_oa >= 0.8
          erv_cfm = nil
        end
      when 'ASHRAE 169-2006-1B', 'ASHRAE 169-2006-2B', 'ASHRAE 169-2006-5C'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = nil
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = nil
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = nil
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = nil
        elsif pct_oa >= 0.5 && pct_oa < 0.6
          erv_cfm = 26_000
        elsif pct_oa >= 0.6 && pct_oa < 0.7
          erv_cfm = 12_000
        elsif pct_oa >= 0.7 && pct_oa < 0.8
          erv_cfm = 5000
        elsif pct_oa >= 0.8
          erv_cfm = 4000
        end
      when 'ASHRAE 169-2006-6B'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = 28_000
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = 26_500
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = 11_000
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = 5500
        elsif pct_oa >= 0.5 && pct_oa < 0.6
          erv_cfm = 4500
        elsif pct_oa >= 0.6 && pct_oa < 0.7
          erv_cfm = 3500
        elsif pct_oa >= 0.7 && pct_oa < 0.8
          erv_cfm = 2500
        elsif pct_oa >= 0.8
          erv_cfm = 1500
        end
      when 'ASHRAE 169-2006-1A', 'ASHRAE 169-2006-2A', 'ASHRAE 169-2006-3A', 'ASHRAE 169-2006-4A', 'ASHRAE 169-2006-5A', 'ASHRAE 169-2006-6A'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = 26_000
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = 16_000
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = 5500
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = 4500
        elsif pct_oa >= 0.5 && pct_oa < 0.6
          erv_cfm = 3500
        elsif pct_oa >= 0.6 && pct_oa < 0.7
          erv_cfm = 2000
        elsif pct_oa >= 0.7 && pct_oa < 0.8
          erv_cfm = 1000
        elsif pct_oa >= 0.8
          erv_cfm = 0
        end
      when 'ASHRAE 169-2006-7A', 'ASHRAE 169-2006-7B', 'ASHRAE 169-2006-8A', 'ASHRAE 169-2006-8B'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = 4500
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = 4000
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = 2500
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = 1000
        elsif pct_oa >= 0.5 && pct_oa < 0.6
          erv_cfm = 0
        elsif pct_oa >= 0.6 && pct_oa < 0.7
          erv_cfm = 0
        elsif pct_oa >= 0.7 && pct_oa < 0.8
          erv_cfm = 0
        elsif pct_oa >= 0.8
          erv_cfm = 0
        end
      end
    else
      # Table 6.5.6.1-2, above 8000 hrs
      case climate_zone
      when 'ASHRAE 169-2006-3C'
        erv_cfm = nil
      when 'ASHRAE 169-2006-1B', 'ASHRAE 169-2006-2B', 'ASHRAE 169-2006-3B', 'ASHRAE 169-2006-4C', 'ASHRAE 169-2006-5C'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = nil
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = 19_500
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = 9000
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = 5000
        elsif pct_oa >= 0.5 && pct_oa < 0.6
          erv_cfm = 4000
        elsif pct_oa >= 0.6 && pct_oa < 0.7
          erv_cfm = 3000
        elsif pct_oa >= 0.7 && pct_oa < 0.8
          erv_cfm = 1500
        elsif pct_oa >= 0.8
          erv_cfm = 0
        end
      when 'ASHRAE 169-2006-1A', 'ASHRAE 169-2006-2A', 'ASHRAE 169-2006-3A', 'ASHRAE 169-2006-4B', 'ASHRAE 169-2006-5B'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1 && pct_oa < 0.2
          erv_cfm = 2500
        elsif pct_oa >= 0.2 && pct_oa < 0.3
          erv_cfm = 2000
        elsif pct_oa >= 0.3 && pct_oa < 0.4
          erv_cfm = 1000
        elsif pct_oa >= 0.4 && pct_oa < 0.5
          erv_cfm = 500
        elsif pct_oa >= 0.5
          erv_cfm = 0
        end
      when 'ASHRAE 169-2006-4A', 'ASHRAE 169-2006-5A', 'ASHRAE 169-2006-6A', 'ASHRAE 169-2006-6B', 'ASHRAE 169-2006-7A', 'ASHRAE 169-2006-7B', 'ASHRAE 169-2006-8A', 'ASHRAE 169-2006-8B'
        if pct_oa < 0.1
          erv_cfm = nil
        elsif pct_oa >= 0.1
          erv_cfm = 0
        end
      end
    end
  when 'NECB 2011'
    # The NECB 2011 requirement is that systems with an exhaust heat content > 150 kW require an HRV
    # The calculation for this is done below, to modify erv_required
    # erv_cfm set to nil here as placeholder, will lead to erv_required = false
    erv_cfm = nil
  end

  # Determine if an ERV is required
  # erv_required = nil
  if erv_cfm.nil?
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV not required based on #{(pct_oa * 100).round}% OA flow, design supply air flow of #{dsn_flow_cfm.round}cfm, and climate zone #{climate_zone}.")
    erv_required = false
  elsif dsn_flow_cfm < erv_cfm
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV not required based on #{(pct_oa * 100).round}% OA flow, design supply air flow of #{dsn_flow_cfm.round}cfm, and climate zone #{climate_zone}. Does not exceed minimum flow requirement of #{erv_cfm}cfm.")
    erv_required = false
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV required based on #{(pct_oa * 100).round}% OA flow, design supply air flow of #{dsn_flow_cfm.round}cfm, and climate zone #{climate_zone}. Exceeds minimum flow requirement of #{erv_cfm}cfm.")
    erv_required = true
  end

  # This code modifies erv_required for NECB 2011
  # Calculation of exhaust heat content and check whether it is > 150 kW

  if template == 'NECB 2011'

    # get all zones in the model
    zones = thermalZones

    # initialize counters
    sum_zone_oa = 0.0
    sum_zone_oa_times_heat_design_t = 0.0

    # zone loop
    zones.each do |zone|
      # get design heat temperature for each zone; this is equivalent to design exhaust temperature
      zone_sizing = zone.sizingZone
      heat_design_t = zone_sizing.zoneHeatingDesignSupplyAirTemperature

      # initialize counter
      zone_oa = 0.0
      # outdoor defined at space level; get OA flow for all spaces within zone
      spaces = zone.spaces

      # space loop
      spaces.each do |space|
        unless space.designSpecificationOutdoorAir.empty? # if empty, don't do anything
          outdoor_air = space.designSpecificationOutdoorAir.get

          # in bTAP, outdoor air specified as outdoor air per person (m3/s/person)
          oa_flow_per_person = outdoor_air.outdoorAirFlowperPerson
          num_people = space.peoplePerFloorArea * space.floorArea
          oa_flow = oa_flow_per_person * num_people # oa flow for the space
          zone_oa += oa_flow # add up oa flow for all spaces to get zone air flow
        end
      end # space loop

      sum_zone_oa += zone_oa # sum of all zone oa flows to get system oa flow
      sum_zone_oa_times_heat_design_t += (zone_oa * heat_design_t) # calculated to get oa flow weighted average of design exhaust temperature
    end # zone loop

    # Calculate average exhaust temperature (oa flow weighted average)
    avg_exhaust_temp = sum_zone_oa_times_heat_design_t / sum_zone_oa

    # for debugging/testing
    #      puts "average exhaust temp = #{avg_exhaust_temp}"
    #      puts "sum_zone_oa = #{sum_zone_oa}"

    # Get January winter design temperature
    # get model weather file name
    weather_file = BTAP::Environment::WeatherFile.new(model.weatherFile.get.path.get)

    # get winter(heating) design temp stored in array
    # Note that the NECB 2011 specifies using the 2.5% january design temperature
    # The outdoor temperature used here is the 0.4% heating design temperature of the coldest month, available in stat file
    outdoor_temp = weather_file.heating_design_info[1]

    #      for debugging/testing
    #      puts "outdoor design temp = #{outdoor_temp}"

    # Calculate exhaust heat content
    exhaust_heat_content = 0.00123 * sum_zone_oa * 1000.0 * (avg_exhaust_temp - outdoor_temp)

    # for debugging/testing
    #      puts "exhaust heat content = #{exhaust_heat_content}"

    # Modify erv_required based on exhaust heat content
    if exhaust_heat_content > 150.0
      erv_required = true
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV required based on exhaust heat content.")
    else
      erv_required = false
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, ERV not required based on exhaust heat content.")
    end

  end # of NECB 2011 condition

  # for debugging/testing
  #    puts "erv_required = #{erv_required}"

  return erv_required
end

#fan_power_limitation_pressure_drop_adjustment_brake_horsepower(template = 'ASHRAE 90.1-2007') ⇒ Double

TODO:

Determine the presence of MERV filters and other stuff in Table 6.5.3.1.1B. May need to extend AirLoopHVAC data model

Determine the fan power limitation pressure drop adjustment Per Table 6.5.3.1.1B

Parameters:

  • template (String) (defaults to: 'ASHRAE 90.1-2007') —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

Returns:

  • (Double) —

    fan power limitation pressure drop adjustment units = horsepower



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 238

def fan_power_limitation_pressure_drop_adjustment_brake_horsepower(template = 'ASHRAE 90.1-2007')
  # Get design supply air flow rate (whether autosized or hard-sized)
  dsn_air_flow_m3_per_s = 0
  dsn_air_flow_cfm = 0
  if autosizedDesignSupplyAirFlowRate.is_initialized
    dsn_air_flow_m3_per_s = autosizedDesignSupplyAirFlowRate.get
    dsn_air_flow_cfm = OpenStudio.convert(dsn_air_flow_m3_per_s, 'm^3/s', 'cfm').get
    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "* #{dsn_air_flow_cfm.round} cfm = Autosized Design Supply Air Flow Rate.")
  else
    dsn_air_flow_m3_per_s = designSupplyAirFlowRate.get
    dsn_air_flow_cfm = OpenStudio.convert(dsn_air_flow_m3_per_s, 'm^3/s', 'cfm').get
    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "* #{dsn_air_flow_cfm.round} cfm = Hard sized Design Supply Air Flow Rate.")
  end

  # TODO: determine the presence of MERV filters and other stuff
  # in Table 6.5.3.1.1B
  # perhaps need to extend AirLoopHVAC data model
  has_fully_ducted_return_and_or_exhaust_air_systems = false

  # Calculate Fan Power Limitation Pressure Drop Adjustment (in wc)
  fan_pwr_adjustment_in_wc = 0

  # Fully ducted return and/or exhaust air systems
  if has_fully_ducted_return_and_or_exhaust_air_systems
    adj_in_wc = 0.5
    fan_pwr_adjustment_in_wc += adj_in_wc
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "--Added #{adj_in_wc} in wc for Fully ducted return and/or exhaust air systems")
  end

  # Convert the pressure drop adjustment to brake horsepower (bhp)
  # assuming that all supply air passes through all devices
  fan_pwr_adjustment_bhp = fan_pwr_adjustment_in_wc * dsn_air_flow_cfm / 4131
  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "For #{name}: Fan Power Limitation Pressure Drop Adjustment = #{fan_pwr_adjustment_bhp.round(2)} bhp")

  return fan_pwr_adjustment_bhp
end

#find_design_supply_air_flow_rate ⇒ Double

find design_supply_air_flow_rate

Returns:

  • (Double) —

    design_supply_air_flow_rate m^3/s



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3553

def find_design_supply_air_flow_rate
  # Get the design_supply_air_flow_rate
  design_supply_air_flow_rate = nil
  if designSupplyAirFlowRate.is_initialized
    design_supply_air_flow_rate = designSupplyAirFlowRate.get
  elsif autosizedDesignSupplyAirFlowRate.is_initialized
    design_supply_air_flow_rate = autosizedDesignSupplyAirFlowRate.get
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} design sypply air flow rate is not available.")
  end

  return design_supply_air_flow_rate
end

#floor_area_served ⇒ Object

Calculate the total floor area of all zones attached to the air loop, in m^2.

return [Double] the total floor area of all zones attached to the air loop, in m^2.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3506

def floor_area_served
  total_area = 0.0

  thermalZones.each do |zone|
    total_area += zone.floorArea
  end

  return total_area
end

#floor_area_served_exterior_zones ⇒ Object

Calculate the total floor area of all zones attached to the air loop that have at least one exterior surface, in m^2.

return [Double] the total floor area of all zones attached to the air loop, in m^2.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3538

def floor_area_served_exterior_zones
  total_area = 0.0

  thermalZones.each do |zone|
    # Skip zones that have no exterior surface area
    next if zone.exteriorSurfaceArea.zero?
    total_area += zone.floorArea
  end

  return total_area
end

#floor_area_served_interior_zones ⇒ Object

Calculate the total floor area of all zones attached to the air loop that have no exterior surfaces, in m^2.

return [Double] the total floor area of all zones attached to the air loop, in m^2.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3521

def floor_area_served_interior_zones
  total_area = 0.0

  thermalZones.each do |zone|
    # Skip zones that have exterior surface area
    next if zone.exteriorSurfaceArea > 0
    total_area += zone.floorArea
  end

  return total_area
end

#get_occupancy_schedule(occupied_percentage_threshold = 0.05) ⇒ ScheduleRuleset

TODO:

Speed up this method. Bottleneck is ScheduleRule.getDaySchedules

This method creates a schedule where the value is zero when the overall occupancy for all zones on the airloop is below the specified threshold, and one when the overall occupancy is greater than or equal to the threshold. This method is designed to use the total number of people on the airloop, so if there is a zone that is continuously occupied by a few people, but other zones that are intermittently occupied by many people, the first zone doesn’t drive the entire system.

Parameters:

  • occupied_percentage_threshold (Double) (defaults to: 0.05) —

    the minimum fraction (0 to 1) that counts as occupied

Returns:

  • (ScheduleRuleset) —

    a ScheduleRuleset where 0 = unoccupied, 1 = occupied



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2823

def get_occupancy_schedule(occupied_percentage_threshold = 0.05)
  # Get all the occupancy schedules in every space in every zone
  # served by this airloop.  Include people added via the SpaceType
  # in addition to people hard-assigned to the Space itself.
  occ_schedules_num_occ = {}
  max_occ_on_airloop = 0
  thermalZones.each do |zone|
    # Get the people objects
    zone.spaces.each do |space|
      # From the space type
      if space.spaceType.is_initialized
        space.spaceType.get.people.each do |people|
          num_ppl_sch = people.numberofPeopleSchedule
          if num_ppl_sch.is_initialized
            num_ppl_sch = num_ppl_sch.get
            num_ppl_sch = num_ppl_sch.to_ScheduleRuleset
            next if num_ppl_sch.empty? # Skip non-ruleset schedules
            num_ppl_sch = num_ppl_sch.get
            num_ppl = people.getNumberOfPeople(space.floorArea)
            if occ_schedules_num_occ[num_ppl_sch].nil?
              occ_schedules_num_occ[num_ppl_sch] = num_ppl
            else
              occ_schedules_num_occ[num_ppl_sch] += num_ppl
            end
            max_occ_on_airloop += num_ppl
          end
        end
      end
      # From the space
      space.people.each do |people|
        num_ppl_sch = people.numberofPeopleSchedule
        if num_ppl_sch.is_initialized
          num_ppl_sch = num_ppl_sch.get
          num_ppl_sch = num_ppl_sch.to_ScheduleRuleset
          next if num_ppl_sch.empty? # Skip non-ruleset schedules
          num_ppl_sch = num_ppl_sch.get
          num_ppl = people.getNumberOfPeople(space.floorArea)
          if occ_schedules_num_occ[num_ppl_sch].nil?
            occ_schedules_num_occ[num_ppl_sch] = num_ppl
          else
            occ_schedules_num_occ[num_ppl_sch] += num_ppl
          end
          max_occ_on_airloop += num_ppl
        end
      end
    end
  end

  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "#{name} has #{occ_schedules_num_occ.size} unique occ schedules.")
  occ_schedules_num_occ.each do |occ_sch, num_occ|
    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "   #{occ_sch.name} - #{num_occ.round} people")
  end
  OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "   Total #{max_occ_on_airloop.round} people on #{name}")

  # For each day of the year, determine
  # time_value_pairs = []
  year = model.getYearDescription
  yearly_data = []
  yearly_times = OpenStudio::DateTimeVector.new
  yearly_values = []
  (1..365).each do |i|
    times_on_this_day = []
    os_date = year.makeDate(i)
    day_of_week = os_date.dayOfWeek.valueName

    # Get the unique time indices and corresponding day schedules
    occ_schedules_day_schs = {}
    day_sch_num_occ = {}
    occ_schedules_num_occ.each do |occ_sch, num_occ|
      # Get the day schedules for this day
      # (there should only be one)
      day_schs = occ_sch.getDaySchedules(os_date, os_date)
      OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "Schedule #{occ_sch.name} has #{day_schs.size} day schs") unless day_schs.size == 1
      day_schs[0].times.each do |time|
        times_on_this_day << time.toString
      end
      day_sch_num_occ[day_schs[0]] = num_occ
    end

    # Determine the total fraction for the airloop at each time
    daily_times = []
    daily_os_times = []
    daily_values = []
    daily_occs = []
    times_on_this_day.uniq.sort.each do |time|
      os_time = OpenStudio::Time.new(time)
      os_date_time = OpenStudio::DateTime.new(os_date, os_time)
      # Total number of people at each time
      tot_occ_at_time = 0
      day_sch_num_occ.each do |day_sch, num_occ|
        occ_frac = day_sch.getValue(os_time)
        tot_occ_at_time += occ_frac * num_occ
      end

      # Total fraction for the airloop at each time
      air_loop_occ_frac = tot_occ_at_time / max_occ_on_airloop
      occ_status = 0 # unoccupied
      if air_loop_occ_frac >= occupied_percentage_threshold
        occ_status = 1
      end

      # Add this data to the daily arrays
      daily_times << time
      daily_os_times << os_time
      daily_values << occ_status
      daily_occs << air_loop_occ_frac.round(2)
    end

    # OpenStudio::logFree(OpenStudio::Debug, "openstudio.standards.AirLoopHVAC", "#{daily_times.join(', ')}                  #{daily_values.join(', ')}")

    # Simplify the daily times to eliminate intermediate
    # points with the same value as the following point.
    simple_daily_times = []
    simple_daily_os_times = []
    simple_daily_values = []
    simple_daily_occs = []
    daily_values.each_with_index do |value, j|
      next if value == daily_values[j + 1]
      simple_daily_times << daily_times[j]
      simple_daily_os_times << daily_os_times[j]
      simple_daily_values << daily_values[j]
      simple_daily_occs << daily_occs[j]
    end

    # OpenStudio::logFree(OpenStudio::Debug, "openstudio.standards.AirLoopHVAC", "#{simple_daily_times.join(', ')}                  {simple_daily_values.join(', ')}")

    # Store the daily values
    yearly_data << { 'date' => os_date, 'day_of_week' => day_of_week, 'times' => simple_daily_times, 'values' => simple_daily_values, 'daily_os_times' => simple_daily_os_times, 'daily_occs' => simple_daily_occs }
  end

  # Create a TimeSeries from the data
  # time_series = OpenStudio::TimeSeries.new(times, values, 'unitless')

  # Make a schedule ruleset
  sch_name = "#{name} Occ Sch"
  sch_ruleset = OpenStudio::Model::ScheduleRuleset.new(model)
  sch_ruleset.setName(sch_name.to_s)

  # Default - All Occupied
  day_sch = sch_ruleset.defaultDaySchedule
  day_sch.setName("#{sch_name} Default")
  day_sch.addValue(OpenStudio::Time.new(0, 24, 0, 0), 1)

  # Winter Design Day - All Occupied
  day_sch = OpenStudio::Model::ScheduleDay.new(model)
  sch_ruleset.setWinterDesignDaySchedule(day_sch)
  day_sch = sch_ruleset.winterDesignDaySchedule
  day_sch.setName("#{sch_name} Winter Design Day")
  day_sch.addValue(OpenStudio::Time.new(0, 24, 0, 0), 1)

  # Summer Design Day - All Occupied
  day_sch = OpenStudio::Model::ScheduleDay.new(model)
  sch_ruleset.setSummerDesignDaySchedule(day_sch)
  day_sch = sch_ruleset.summerDesignDaySchedule
  day_sch.setName("#{sch_name} Summer Design Day")
  day_sch.addValue(OpenStudio::Time.new(0, 24, 0, 0), 1)

  # Create ruleset schedules, attempting to create
  # the minimum number of unique rules.
  ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'].each do |weekday|
    OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', weekday.to_s)
    end_of_prev_rule = yearly_data[0]['date']
    yearly_data.each_with_index do |daily_data, k|
      # Skip unless it is the day of week
      # currently under inspection
      day = daily_data['day_of_week']
      next unless day == weekday
      date = daily_data['date']
      times = daily_data['times']
      values = daily_data['values']
      daily_occs = daily_data['daily_occs']

      # If the next (Monday, Tuesday, etc.)
      # is the same as today, keep going.
      # If the next is different, or if
      # we've reached the end of the year,
      # create a new rule
      unless yearly_data[k + 7].nil?
        next_day_times = yearly_data[k + 7]['times']
        next_day_values = yearly_data[k + 7]['values']
        next if times == next_day_times && values == next_day_values
      end

      daily_os_times = daily_data['daily_os_times']
      daily_occs = daily_data['daily_occs']

      # If here, we need to make a rule to cover from the previous
      # rule to today
      OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "Making a new rule for #{weekday} from #{end_of_prev_rule} to #{date}")
      sch_rule = OpenStudio::Model::ScheduleRule.new(sch_ruleset)
      sch_rule.setName("#{sch_name} #{weekday} Rule")
      day_sch = sch_rule.daySchedule
      day_sch.setName("#{sch_name} #{weekday}")
      daily_os_times.each_with_index do |time, t|
        value = values[t]
        next if value == values[t + 1] # Don't add breaks if same value
        day_sch.addValue(time, value)
        OpenStudio.logFree(OpenStudio::Debug, 'openstudio.standards.AirLoopHVAC', "   Adding value #{time}, #{value}")
      end

      # Set the dates when the rule applies
      sch_rule.setStartDate(end_of_prev_rule)
      sch_rule.setEndDate(date)

      # Individual Days
      sch_rule.setApplyMonday(true) if weekday == 'Monday'
      sch_rule.setApplyTuesday(true) if weekday == 'Tuesday'
      sch_rule.setApplyWednesday(true) if weekday == 'Wednesday'
      sch_rule.setApplyThursday(true) if weekday == 'Thursday'
      sch_rule.setApplyFriday(true) if weekday == 'Friday'
      sch_rule.setApplySaturday(true) if weekday == 'Saturday'
      sch_rule.setApplySunday(true) if weekday == 'Sunday'

      # Reset the previous rule end date
      end_of_prev_rule = date + OpenStudio::Time.new(0, 24, 0, 0)
    end
  end

  return sch_ruleset
end

#motorized_oa_damper_required?(template, climate_zone) ⇒ Boolean

Determine if a motorized OA damper is required

Returns:

  • (Boolean) 


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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2654

def motorized_oa_damper_required?(template, climate_zone)
  motorized_oa_damper_required = false

  if name.to_s.include? 'Outpatient F1'
    motorized_oa_damper_required = true
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: always has a damper, the minimum OA schedule is the same as airloop availability schedule.")
    return motorized_oa_damper_required
  end

  # If the system has an economizer, it must have
  # a motorized damper.
  if economizer?
    motorized_oa_damper_required = true
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Because the system has an economizer, it requires a motorized OA damper.")
    return motorized_oa_damper_required
  end

  # Determine the exceptions based on
  # number of stories, climate zone, and
  # outdoor air intake rates.
  minimum_oa_flow_cfm = 0
  maximum_stories = 0
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004'
    # Assuming that older buildings always
    # used backdraft gravity dampers
    return motorized_oa_damper_required
  when '90.1-2004', '90.1-2007'
    case climate_zone
    when 'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
      minimum_oa_flow_cfm = 300
      maximum_stories = 999 # Any number of stories
    else
      minimum_oa_flow_cfm = 300
      maximum_stories = 3
    end
  when '90.1-2010', '90.1-2013'
    case climate_zone
    when 'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
      minimum_oa_flow_cfm = 300
      maximum_stories = 999 # Any number of stories
    else
      minimum_oa_flow_cfm = 300
      maximum_stories = 0
    end
  end

  # Get the number of stories
  num_stories = model.getBuildingStorys.size

  # Check the number of stories exception,
  # which is climate-zone dependent.
  if num_stories < maximum_stories
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Motorized OA damper not required because the building has #{num_stories} stories, less than the maximum of #{maximum_stories} stories for climate zone #{climate_zone}.")
    return motorized_oa_damper_required
  end

  # Get the min OA flow rate
  oa_flow_m3_per_s = 0
  if airLoopHVACOutdoorAirSystem.is_initialized
    oa_system = airLoopHVACOutdoorAirSystem.get
    controller_oa = oa_system.getControllerOutdoorAir
    if controller_oa.minimumOutdoorAirFlowRate.is_initialized
      oa_flow_m3_per_s = controller_oa.minimumOutdoorAirFlowRate.get
    elsif controller_oa.autosizedMinimumOutdoorAirFlowRate.is_initialized
      oa_flow_m3_per_s = controller_oa.autosizedMinimumOutdoorAirFlowRate.get
    end
  else
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, Motorized OA damper not applicable because it has no OA intake.")
    return motorized_oa_damper_required
  end
  oa_flow_cfm = OpenStudio.convert(oa_flow_m3_per_s, 'm^3/s', 'cfm').get

  # Check the OA flow rate exception
  if oa_flow_cfm < minimum_oa_flow_cfm
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Motorized OA damper not required because the system OA intake of #{oa_flow_cfm.round} cfm is less than the minimum threshold of #{minimum_oa_flow_cfm} cfm.")
    return motorized_oa_damper_required
  end

  # If here, motorized damper is required
  motorized_oa_damper_required = true

  return motorized_oa_damper_required
end

#multizone_vav_optimization_required?(template, climate_zone) ⇒ Bool

TODO:

Add exception logic for systems with AIA healthcare ventilation requirements dual duct systems

Determine if multizone vav optimization is required.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1870

def multizone_vav_optimization_required?(template, climate_zone)
  multizone_opt_required = false

  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007'

    # Not required before 90.1-2010
    return multizone_opt_required

  when '90.1-2010', '90.1-2013'

    # Not required for systems with fan-powered terminals
    num_fan_powered_terminals = 0
    demandComponents.each do |comp|
      if comp.to_AirTerminalSingleDuctParallelPIUReheat.is_initialized || comp.to_AirTerminalSingleDuctSeriesPIUReheat.is_initialized
        num_fan_powered_terminals += 1
      end
    end
    if num_fan_powered_terminals > 0
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, multizone vav optimization is not required because the system has #{num_fan_powered_terminals} fan-powered terminals.")
      return multizone_opt_required
    end

    # Not required for systems that require an ERV
    if energy_recovery?
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: multizone vav optimization is not required because the system has Energy Recovery.")
      return multizone_opt_required
    end

    # Get the OA intake
    controller_oa = nil
    controller_mv = nil
    oa_system = nil
    if airLoopHVACOutdoorAirSystem.is_initialized
      oa_system = airLoopHVACOutdoorAirSystem.get
      controller_oa = oa_system.getControllerOutdoorAir
      controller_mv = controller_oa.controllerMechanicalVentilation
    else
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}, multizone optimization is not applicable because system has no OA intake.")
      return multizone_opt_required
    end

    # Get the AHU design supply air flow rate
    dsn_flow_m3_per_s = nil
    if designSupplyAirFlowRate.is_initialized
      dsn_flow_m3_per_s = designSupplyAirFlowRate.get
    elsif autosizedDesignSupplyAirFlowRate.is_initialized
      dsn_flow_m3_per_s = autosizedDesignSupplyAirFlowRate.get
    else
      OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} design supply air flow rate is not available, cannot apply efficiency standard.")
      return multizone_opt_required
    end
    dsn_flow_cfm = OpenStudio.convert(dsn_flow_m3_per_s, 'm^3/s', 'cfm').get

    # Get the minimum OA flow rate
    min_oa_flow_m3_per_s = nil
    if controller_oa.minimumOutdoorAirFlowRate.is_initialized
      min_oa_flow_m3_per_s = controller_oa.minimumOutdoorAirFlowRate.get
    elsif controller_oa.autosizedMinimumOutdoorAirFlowRate.is_initialized
      min_oa_flow_m3_per_s = controller_oa.autosizedMinimumOutdoorAirFlowRate.get
    else
      OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{controller_oa.name}: minimum OA flow rate is not available, cannot apply efficiency standard.")
      return multizone_opt_required
    end
    min_oa_flow_cfm = OpenStudio.convert(min_oa_flow_m3_per_s, 'm^3/s', 'cfm').get

    # Calculate the percent OA at design airflow
    pct_oa = min_oa_flow_m3_per_s / dsn_flow_m3_per_s

    # Not required for systems where
    # exhaust is more than 70% of the total OA intake.
    if pct_oa > 0.7
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{controller_oa.name}: multizone optimization is not applicable because system is more than 70% OA.")
      return multizone_opt_required
    end

    # TODO: Not required for dual-duct systems
    # if self.isDualDuct
    # OpenStudio::logFree(OpenStudio::Info, "openstudio.standards.AirLoopHVAC", "For #{controller_oa.name}: multizone optimization is not applicable because it is a dual duct system")
    # return multizone_opt_required
    # end

    # If here, multizone vav optimization is required
    multizone_opt_required = true

    return multizone_opt_required

  end
end

#multizone_vav_system? ⇒ Bool

Determine if the system is a multizone VAV system

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2537

def multizone_vav_system?
  multizone_vav_system = false

  # Must serve more than 1 zone
  if thermalZones.size < 2
    return multizone_vav_system
  end

  # Must be a variable volume system
  has_vav_fan = false
  supplyComponents.each do |comp|
    if comp.to_FanVariableVolume.is_initialized
      has_vav_fan = true
    end
  end
  if has_vav_fan == false
    return multizone_vav_system
  end

  # If here, it's a multizone VAV system
  multizone_vav_system = true

  return multizone_vav_system
end

#prm_baseline_economizer_required?(template, climate_zone) ⇒ Bool

Determine if an economizer is required per the PRM.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    returns true if required, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 1035

def prm_baseline_economizer_required?(template, climate_zone)
  economizer_required = false

  # A big number of ft2 as the minimum requirement
  infinity_ft2 = 999_999_999_999
  min_int_area_served_ft2 = infinity_ft2
  min_ext_area_served_ft2 = infinity_ft2

  # Determine the minimum capacity that requires an economizer
  case template
  when '90.1-2004'
    case climate_zone
    when 'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-4A'
      min_int_area_served_ft2 = infinity_ft2 # No requirement
      min_ext_area_served_ft2 = infinity_ft2 # No requirement
    when 'ASHRAE 169-2006-2B',
        'ASHRAE 169-2006-5A',
        'ASHRAE 169-2006-6A',
        'ASHRAE 169-2006-7A',
        'ASHRAE 169-2006-7B',
        'ASHRAE 169-2006-8A',
        'ASHRAE 169-2006-8B'
      min_int_area_served_ft2 = 15_000
      min_ext_area_served_ft2 = infinity_ft2 # No requirement
    when 'ASHRAE 169-2006-3B',
        'ASHRAE 169-2006-3C',
        'ASHRAE 169-2006-4B',
        'ASHRAE 169-2006-4C',
        'ASHRAE 169-2006-5B',
        'ASHRAE 169-2006-5C',
        'ASHRAE 169-2006-6B'
      min_int_area_served_ft2 = 10_000
      min_ext_area_served_ft2 = 25_000
    end
  when '90.1-2007', '90.1-2010', '90.1-2013'
    case climate_zone
    when 'ASHRAE 169-2006-1A',
        'ASHRAE 169-2006-1B',
        'ASHRAE 169-2006-2A',
        'ASHRAE 169-2006-3A',
        'ASHRAE 169-2006-4A'
      min_int_area_served_ft2 = infinity_ft2 # No requirement
      min_ext_area_served_ft2 = infinity_ft2 # No requirement
    else
      min_int_area_served_ft2 = 0 # Always required
      min_ext_area_served_ft2 = 0 # Always required
    end
  end

  # Check whether the system requires an economizer by comparing
  # the system capacity to the minimum capacity.
  min_int_area_served_m2 = OpenStudio.convert(min_int_area_served_ft2, 'ft^2', 'm^2').get
  min_ext_area_served_m2 = OpenStudio.convert(min_ext_area_served_ft2, 'ft^2', 'm^2').get

  # Get the interior and exterior area served
  int_area_served_m2 = floor_area_served_interior_zones
  ext_area_served_m2 = floor_area_served_exterior_zones

  # Check the floor area exception
  if int_area_served_m2 < min_int_area_served_m2 && ext_area_served_m2 < min_ext_area_served_m2
    if min_int_area_served_ft2 == infinity_ft2 && min_ext_area_served_ft2 == infinity_ft2
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer not required for climate zone #{climate_zone}.")
    else
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer not required for because the interior area served of #{int_area_served_m2} ft2 < minimum of #{min_int_area_served_m2} and the perimeter area served of #{ext_area_served_m2} ft2 < minimum of #{min_ext_area_served_m2} for climate zone #{climate_zone}.")
    end
    return economizer_required
  end

  # If here, economizer required
  economizer_required = true
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Economizer required for the performance rating method baseline.")

  return economizer_required
end

#remove_motorized_oa_damper ⇒ Object

Remove a motorized OA damper by modifying the OA schedule to require full OA at all times. Whenever the fan operates, the damper will be open and OA will be brought into the building. This reflects the use of a backdraft gravity damper, and increases building loads unnecessarily during unoccupied hours.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2795

def remove_motorized_oa_damper
  # Get the OA system and OA controller
  oa_sys = airLoopHVACOutdoorAirSystem
  if oa_sys.is_initialized
    oa_sys = oa_sys.get
  else
    return false # No OA system
  end
  oa_control = oa_sys.getControllerOutdoorAir

  # Set the minimum OA schedule to always 1 (100%)
  oa_control.setMinimumOutdoorAirSchedule(model.alwaysOnDiscreteSchedule)

  return true
end

#static_pressure_reset_required?(template, has_ddc) ⇒ Boolean

TODO:

Instead of requiring the input of whether a system has DDC control of VAV terminals or not, determine this from the system itself. This may require additional information be added to the OpenStudio data model.

Determine if static pressure reset is required for this system. For 90.1, this determination needs information about whether or not the system has DDC control over the VAV terminals.

over VAV terminals. return [Bool] returns true if static pressure reset is required, false if not

Parameters:

  • template (String) —

    the template base requirements on

  • has_ddc (Bool) —

    whether or not the system has DDC control

Returns:

  • (Boolean) 


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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3405

def static_pressure_reset_required?(template, has_ddc)
  sp_reset_required = false

  # A big number of btu per hr as the minimum requirement
  infinity_btu_per_hr = 999_999_999_999
  minimum_capacity_btu_per_hr = infinity_btu_per_hr

  # Determine the minimum capacity that requires an economizer
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004'
    # static pressure reset not required
  when '90.1-2004', '90.1-2007', '90.1-2010', '90.1-2013'
    if has_ddc
      sp_reset_required = true
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Static pressure reset is required because the system has DDC control of VAV terminals.")
    else
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Static pressure reset not required because the system does not have DDC control of VAV terminals.")
    end
  when 'NECB 2011'
    # static pressure reset not required
  end

  return sp_reset_required
end

#supply_air_temperature_reset_required?(template, climate_zone) ⇒ Bool

Determine if the system required supply air temperature (SAT) reset.

Parameters:

  • template (String) —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

  • climate_zone (String) —

    valid choices: ‘ASHRAE 169-2006-1A’, ‘ASHRAE 169-2006-1B’, ‘ASHRAE 169-2006-2A’, ‘ASHRAE 169-2006-2B’,

Returns:

  • (Bool) —

    Returns true if required, false if not.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2385

def supply_air_temperature_reset_required?(template, climate_zone)
  is_sat_reset_required = false

  # Only required for multizone VAV systems
  return is_sat_reset_required unless multizone_vav_system?

  # Not required until 90.1-2010
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007'
    return is_sat_reset_required
  when '90.1-2010', '90.1-2013'
    case climate_zone
    when 'ASHRAE 169-2006-1A',
      'ASHRAE 169-2006-2A',
      'ASHRAE 169-2006-3A'
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Supply air temperature reset is not required per 6.5.3.4 Exception 1, the system is located in climate zone #{climate_zone}.")
    when 'ASHRAE 169-2006-1B',
      'ASHRAE 169-2006-2B',
      'ASHRAE 169-2006-3B',
      'ASHRAE 169-2006-3C',
      'ASHRAE 169-2006-4A',
      'ASHRAE 169-2006-4B',
      'ASHRAE 169-2006-4C',
      'ASHRAE 169-2006-5A',
      'ASHRAE 169-2006-5B',
      'ASHRAE 169-2006-5C',
      'ASHRAE 169-2006-6A',
      'ASHRAE 169-2006-6B',
      'ASHRAE 169-2006-7A',
      'ASHRAE 169-2006-7B',
      'ASHRAE 169-2006-8A',
      'ASHRAE 169-2006-8B'
      is_sat_reset_required = true
      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Supply air temperature reset is required.")
      return is_sat_reset_required
    end
  end
end

#supply_return_exhaust_relief_fans ⇒ Array

Get all of the supply, return, exhaust, and relief fans on this system

Returns:

  • (Array) —

    an array of FanConstantVolume, FanVariableVolume, and FanOnOff objects



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 358

def supply_return_exhaust_relief_fans
  # Fans on the supply side of the airloop directly, or inside of unitary equipment.
  fans = []
  sup_and_oa_comps = supplyComponents
  sup_and_oa_comps += oaComponents
  sup_and_oa_comps.each do |comp|
    if comp.to_FanConstantVolume.is_initialized
      fans << comp.to_FanConstantVolume.get
    elsif comp.to_FanVariableVolume.is_initialized
      fans << comp.to_FanVariableVolume.get
    elsif comp.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.is_initialized
      sup_fan = comp.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.get.supplyAirFan
      if sup_fan.to_FanConstantVolume.is_initialized
        fans << sup_fan.to_FanConstantVolume.get
      elsif sup_fan.to_FanOnOff.is_initialized
        fans << sup_fan.to_FanOnOff.get
      end
    elsif comp.to_AirLoopHVACUnitarySystem.is_initialized
      sup_fan = comp.to_AirLoopHVACUnitarySystem.get.supplyFan
      next if sup_fan.empty?
      sup_fan = sup_fan.get
      if sup_fan.to_FanConstantVolume.is_initialized
        fans << sup_fan.to_FanConstantVolume.get
      elsif sup_fan.to_FanOnOff.is_initialized
        fans << sup_fan.to_FanOnOff.get
      elsif sup_fan.to_FanVariableVolume.is_initialized
        fans << sup_fan.to_FanVariableVolume.get
      end
    end
  end

  return fans
end

#system_fan_brake_horsepower(include_terminal_fans = true, template = 'ASHRAE 90.1-2007') ⇒ Double

Determine the total brake horsepower of the fans on the system with or without the fans inside of fan powered terminals.

Parameters:

  • include_terminal_fans (Bool) (defaults to: true) —

    if true, power from fan powered terminals will be included

  • template (String) (defaults to: 'ASHRAE 90.1-2007') —

    valid choices: ‘DOE Ref Pre-1980’, ‘DOE Ref 1980-2004’, ‘90.1-2004’, ‘90.1-2007’, ‘90.1-2010’, ‘90.1-2013’

Returns:

  • (Double) —

    total brake horsepower of the fans on the system units = horsepower



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 399

def system_fan_brake_horsepower(include_terminal_fans = true, template = 'ASHRAE 90.1-2007')
  # TODO: get the template from the parent model itself?
  # Or not because maybe you want to see the difference between two standards?
  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "#{name}-Determining #{template} allowable system fan power.")

  # Get all fans
  fans = []
  # Supply, exhaust, relief, and return fans
  fans += supply_return_exhaust_relief_fans

  # Fans inside of fan-powered terminals
  if include_terminal_fans
    demandComponents.each do |comp|
      if comp.to_AirTerminalSingleDuctSeriesPIUReheat.is_initialized
        term_fan = comp.to_AirTerminalSingleDuctSeriesPIUReheat.get.supplyAirFan
        if term_fan.to_FanConstantVolume.is_initialized
          fans << term_fan.to_FanConstantVolume.get
        end
      elsif comp.to_AirTerminalSingleDuctParallelPIUReheat.is_initialized
        term_fan = comp.to_AirTerminalSingleDuctParallelPIUReheat.get.fan
        if term_fan.to_FanConstantVolume.is_initialized
          fans << term_fan.to_FanConstantVolume.get
        end
      end
    end
  end

  # Loop through all fans on the system and
  # sum up their brake horsepower values.
  sys_fan_bhp = 0
  fans.sort.each do |fan|
    sys_fan_bhp += fan.brake_horsepower
  end

  return sys_fan_bhp
end

#system_multiplier ⇒ Integer

Determine if every zone on the system has an identical multiplier. If so, return this number. If not, return 1.

Returns:

  • (Integer) —

    an integer representing the system multiplier.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3673

def system_multiplier
  mult = 1

  # Get all the zone multipliers
  zn_mults = []
  thermalZones.each do |zone|
    zn_mults << zone.multiplier
  end
 
  # Warn if there are different multipliers
  uniq_mults = zn_mults.uniq
  if uniq_mults.size > 1
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name}: not all zones on the system have an identical zone multiplier.  Multipliers are: #{uniq_mults.join(', ')}.")
  else
    mult = uniq_mults[0]
  end

  return mult
end

#terminal_reheat? ⇒ Bool

Determine if the system has terminal reheat

Returns:

  • (Bool) —

    returns true if has one or more reheat terminals, false if it doesn’t.



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 2565

def terminal_reheat?
  has_term_rht = false
  demandComponents.each do |sc|
    if sc.to_AirTerminalSingleDuctConstantVolumeReheat.is_initialized ||
       sc.to_AirTerminalSingleDuctParallelPIUReheat.is_initialized ||
       sc.to_AirTerminalSingleDuctSeriesPIUReheat.is_initialized ||
       sc.to_AirTerminalSingleDuctVAVHeatAndCoolReheat.is_initialized ||
       sc.to_AirTerminalSingleDuctVAVReheat.is_initialized
       has_term_rht = true
       break
    end
  end

  return has_term_rht  
end

#total_cooling_capacity ⇒ Double

TODO:

Change to pull water coil nominal capacity instead of design load; not a huge difference, but water coil nominal capacity not available in sizing table.

TODO:

Handle all additional cooling coil types. Currently only handles CoilCoolingDXSingleSpeed, CoilCoolingDXTwoSpeed, and CoilCoolingWater

Get the total cooling capacity for the air loop

Returns:

  • (Double) —

    total cooling capacity units = Watts (W)



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 527

def total_cooling_capacity
  # Sum the cooling capacity for all cooling components
  # on the airloop, which may be inside of unitary systems.
  total_cooling_capacity_w = 0
  supplyComponents.each do |sc|
    # CoilCoolingDXSingleSpeed
    if sc.to_CoilCoolingDXSingleSpeed.is_initialized
      coil = sc.to_CoilCoolingDXSingleSpeed.get
      if coil.ratedTotalCoolingCapacity.is_initialized
        total_cooling_capacity_w += coil.ratedTotalCoolingCapacity.get
      elsif coil.autosizedRatedTotalCoolingCapacity.is_initialized
        total_cooling_capacity_w += coil.autosizedRatedTotalCoolingCapacity.get
      else
        OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
      end
      # CoilCoolingDXTwoSpeed
    elsif sc.to_CoilCoolingDXTwoSpeed.is_initialized
      coil = sc.to_CoilCoolingDXTwoSpeed.get
      if coil.ratedHighSpeedTotalCoolingCapacity.is_initialized
        total_cooling_capacity_w += coil.ratedHighSpeedTotalCoolingCapacity.get
      elsif coil.autosizedRatedHighSpeedTotalCoolingCapacity.is_initialized
        total_cooling_capacity_w += coil.autosizedRatedHighSpeedTotalCoolingCapacity.get
      else
        OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
      end
      # CoilCoolingWater
    elsif sc.to_CoilCoolingWater.is_initialized
      coil = sc.to_CoilCoolingWater.get
      if coil.autosizedDesignCoilLoad.is_initialized # TODO: Change to pull water coil nominal capacity instead of design load
        total_cooling_capacity_w += coil.autosizedDesignCoilLoad.get
      else
        OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
      end
      # CoilCoolingWaterToAirHeatPumpEquationFit
    elsif sc.to_CoilCoolingWaterToAirHeatPumpEquationFit.is_initialized
      coil = sc.to_CoilCoolingWaterToAirHeatPumpEquationFit.get
      if coil.ratedTotalCoolingCapacity.is_initialized
        total_cooling_capacity_w += coil.ratedTotalCoolingCapacity.get
      elsif coil.autosizedRatedTotalCoolingCapacity.is_initialized
        total_cooling_capacity_w += coil.autosizedRatedTotalCoolingCapacity.get
      else
        OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
      end
    elsif sc.to_AirLoopHVACUnitarySystem.is_initialized
      unitary = sc.to_AirLoopHVACUnitarySystem.get
      if unitary.coolingCoil.is_initialized
        clg_coil = unitary.coolingCoil.get
        # CoilCoolingDXSingleSpeed
        if clg_coil.to_CoilCoolingDXSingleSpeed.is_initialized
          coil = clg_coil.to_CoilCoolingDXSingleSpeed.get
          if coil.ratedTotalCoolingCapacity.is_initialized
            total_cooling_capacity_w += coil.ratedTotalCoolingCapacity.get
          elsif coil.autosizedRatedTotalCoolingCapacity.is_initialized
            total_cooling_capacity_w += coil.autosizedRatedTotalCoolingCapacity.get
          else
            OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
          end
        # CoilCoolingDXTwoSpeed
        elsif clg_coil.to_CoilCoolingDXTwoSpeed.is_initialized
          coil = clg_coil.to_CoilCoolingDXTwoSpeed.get
          if coil.ratedHighSpeedTotalCoolingCapacity.is_initialized
            total_cooling_capacity_w += coil.ratedHighSpeedTotalCoolingCapacity.get
          elsif coil.autosizedRatedHighSpeedTotalCoolingCapacity.is_initialized
            total_cooling_capacity_w += coil.autosizedRatedHighSpeedTotalCoolingCapacity.get
          else
            OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
          end
        # CoilCoolingWater
        elsif clg_coil.to_CoilCoolingWater.is_initialized
          coil = clg_coil.to_CoilCoolingWater.get
          if coil.autosizedDesignCoilLoad.is_initialized # TODO: Change to pull water coil nominal capacity instead of design load
            total_cooling_capacity_w += coil.autosizedDesignCoilLoad.get
          else
            OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
          end
        # CoilCoolingWaterToAirHeatPumpEquationFit
        elsif clg_coil.to_CoilCoolingWaterToAirHeatPumpEquationFit.is_initialized
          coil = clg_coil.to_CoilCoolingWaterToAirHeatPumpEquationFit.get
          if coil.ratedTotalCoolingCapacity.is_initialized
            total_cooling_capacity_w += coil.ratedTotalCoolingCapacity.get
          elsif coil.autosizedRatedTotalCoolingCapacity.is_initialized
            total_cooling_capacity_w += coil.autosizedRatedTotalCoolingCapacity.get
          else
            OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
          end
        end
      end
    elsif sc.to_AirLoopHVACUnitaryHeatPumpAirToAir.is_initialized
      unitary = sc.to_AirLoopHVACUnitaryHeatPumpAirToAir.get
      clg_coil = unitary.coolingCoil
      # CoilCoolingDXSingleSpeed
      if clg_coil.to_CoilCoolingDXSingleSpeed.is_initialized
        coil = clg_coil.to_CoilCoolingDXSingleSpeed.get
        if coil.ratedTotalCoolingCapacity.is_initialized
          total_cooling_capacity_w += coil.ratedTotalCoolingCapacity.get
        elsif coil.autosizedRatedTotalCoolingCapacity.is_initialized
          total_cooling_capacity_w += coil.autosizedRatedTotalCoolingCapacity.get
        else
          OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
        end
      # CoilCoolingDXTwoSpeed
      elsif clg_coil.to_CoilCoolingDXTwoSpeed.is_initialized
        coil = clg_coil.to_CoilCoolingDXTwoSpeed.get
        if coil.ratedHighSpeedTotalCoolingCapacity.is_initialized
          total_cooling_capacity_w += coil.ratedHighSpeedTotalCoolingCapacity.get
        elsif coil.autosizedRatedHighSpeedTotalCoolingCapacity.is_initialized
          total_cooling_capacity_w += coil.autosizedRatedHighSpeedTotalCoolingCapacity.get
        else
          OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
        end
      # CoilCoolingWater
      elsif clg_coil.to_CoilCoolingWater.is_initialized
        coil = clg_coil.to_CoilCoolingWater.get
        if coil.autosizedDesignCoilLoad.is_initialized # TODO: Change to pull water coil nominal capacity instead of design load
          total_cooling_capacity_w += coil.autosizedDesignCoilLoad.get
        else
          OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "For #{name} capacity of #{coil.name} is not available, total cooling capacity of air loop will be incorrect when applying standard.")
        end
      end
    elsif sc.to_CoilCoolingDXMultiSpeed.is_initialized ||
          sc.to_CoilCoolingCooledBeam.is_initialized ||
          sc.to_AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass.is_initialized ||
          sc.to_AirLoopHVACUnitaryHeatPumpAirToAirMultiSpeed.is_initialized ||
          sc.to_AirLoopHVACUnitarySystem.is_initialized
      OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.AirLoopHVAC', "#{name} has a cooling coil named #{sc.name}, whose type is not yet covered by economizer checks.")
      # CoilCoolingDXMultiSpeed
      # CoilCoolingCooledBeam
      # CoilCoolingWaterToAirHeatPumpEquationFit
      # AirLoopHVACUnitaryHeatCoolVAVChangeoverBypass
      # AirLoopHVACUnitaryHeatPumpAirToAir
      # AirLoopHVACUnitaryHeatPumpAirToAirMultiSpeed
      # AirLoopHVACUnitarySystem
    end
  end

  return total_cooling_capacity_w
end

#unoccupied_fan_shutoff_required?(template) ⇒ Bool

Determine if a system’s fans must shut off when not required.

Parameters:

Returns:

  • (Bool) —

    true if required, false if not



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# File 'lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb', line 3435

def unoccupied_fan_shutoff_required?(template)
  shutoff_required = true

  # Per 90.1 6.4.3.4.5, systems less than 0.75 HP
  # must turn off when unoccupied.
  minimum_fan_hp = nil
  case template
  when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004', '90.1-2007', '90.1-2010', '90.1-2013', 'NECB 2011'
    minimum_fan_hp = 0.75
  end

  # Determine the system fan horsepower
  total_hp = 0.0
  supply_return_exhaust_relief_fans.each do |fan|
    total_hp += fan.motor_horsepower
  end

  # Check the HP exception
  if total_hp < minimum_fan_hp
    shutoff_required = false
    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{name}: Unoccupied fan shutoff not required because system fan HP of #{total_hp.round(2)} HP is less than the minimum threshold of #{minimum_fan_hp} HP.")
  end

  return shutoff_required
end