Module: PrototypeFan
- Included in:
- OpenStudio::Model::FanConstantVolume, OpenStudio::Model::FanOnOff, OpenStudio::Model::FanVariableVolume, OpenStudio::Model::FanZoneExhaust
- Defined in:
- lib/openstudio-standards/prototypes/Prototype.Fan.rb
Overview
Prototype fan calculation methods that are the same regardless of fan type. These methods are available to FanConstantVolume, FanOnOff, FanVariableVolume, and FanZoneExhaust
Instance Method Summary collapse
-
#apply_prototype_fan_efficiency(template) ⇒ Bool
Sets the fan motor efficiency using the Prototype model assumptions for fan impeller efficiency, motor type, and a 10% safety factor on brake horsepower.
Instance Method Details
#apply_prototype_fan_efficiency(template) ⇒ Bool
Sets the fan motor efficiency using the Prototype model assumptions for fan impeller efficiency, motor type, and a 10% safety factor on brake horsepower.
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# File 'lib/openstudio-standards/prototypes/Prototype.Fan.rb', line 10 def apply_prototype_fan_efficiency(template) # Get the max flow rate from the fan. maximum_flow_rate_m3_per_s = nil if maximumFlowRate.is_initialized maximum_flow_rate_m3_per_s = maximumFlowRate.get elsif autosizedMaximumFlowRate.is_initialized maximum_flow_rate_m3_per_s = autosizedMaximumFlowRate.get else OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.Fan', "For #{name} max flow rate is not hard sized, cannot apply efficiency standard.") return false end # Convert max flow rate to cfm maximum_flow_rate_cfm = OpenStudio.convert(maximum_flow_rate_m3_per_s, 'm^3/s', 'cfm').get # Get the pressure rise from the fan pressure_rise_pa = pressureRise pressure_rise_in_h2o = OpenStudio.convert(pressure_rise_pa, 'Pa', 'inH_{2}O').get # Get the default impeller efficiency fan_impeller_eff = baseline_impeller_efficiency(template) # Calculate the Brake Horsepower brake_hp = (pressure_rise_in_h2o * maximum_flow_rate_cfm) / (fan_impeller_eff * 6356) allowed_hp = brake_hp * 1.1 # Per PNNL document #TODO add reference if allowed_hp > 0.1 allowed_hp = allowed_hp.round(2) + 0.0001 elsif allowed_hp < 0.01 allowed_hp = 0.01 end # Minimum motor size for efficiency lookup # is 1 HP unless the motor serves an exhaust fan, # a powered VAV terminal, or a fan coil unit. unless small_fan? if allowed_hp < 1.0 allowed_hp = 1.01 end end # Find the motor efficiency motor_eff, nominal_hp = standard_minimum_motor_efficiency_and_size(template, allowed_hp) # Calculate the total fan efficiency total_fan_eff = fan_impeller_eff * motor_eff # Set the total fan efficiency and the motor efficiency if to_FanZoneExhaust.is_initialized setFanEfficiency(total_fan_eff) else setFanEfficiency(total_fan_eff) setMotorEfficiency(motor_eff) end OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.Fan', "For #{name}: allowed_hp = #{allowed_hp.round(2)}HP; motor eff = #{(motor_eff * 100).round(2)}%; total fan eff = #{(total_fan_eff * 100).round}% based on #{maximum_flow_rate_cfm.round} cfm.") return true end |