Class: OpenStudio::Model::SubSurface

Inherits:
Object
  • Object
show all
Defined in:
lib/openstudio-standards/standards/Standards.SubSurface.rb

Overview

open the class to add methods to apply HVAC efficiency standards

Instance Method Summary collapse

Instance Method Details

#component_infiltration_rate(type) ⇒ Double

Determine the component infiltration rate for this surface

Parameters:

  • type (String) —

    choices are ‘baseline’ and ‘advanced’

Returns:

  • (Double) —

    infiltration rate @units cubic meters per second (m^3/s)



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# File 'lib/openstudio-standards/standards/Standards.SubSurface.rb', line 10

def component_infiltration_rate(type)
     
  comp_infil_rate_m3_per_s = 0.0   
     
  # Define the envelope component infiltration rates
  component_infil_rates_cfm_per_ft2 = {
    'baseline'=>{
      'opaque_door'=>0.40,
      'loading_dock_door'=>0.40,
      'swinging_or_revolving_glass_door'=>1.0,
      'vestibule'=>1.0,
      'sliding_glass_door'=>0.40,
      'window'=>0.40,
      'skylight'=>0.40
    },
    'advanced'=>{
      'opaque_door'=>0.20,
      'loading_dock_door'=>0.20,
      'swinging_or_revolving_glass_door'=>1.0,
      'vestibule'=>1.0,
      'sliding_glass_door'=>0.20,
      'window'=>0.20,
      'skylight'=>0.20
    }
  }
  
  boundary_condition = self.outsideBoundaryCondition
  # Skip non-outdoor surfaces
  return comp_infil_rate_m3_per_s unless self.outsideBoundaryCondition == 'Outdoors' || self.outsideBoundaryCondition == 'Ground'
  
  # Per area infiltration rate for this surface
  surface_type = self.subSurfaceType 
  infil_rate_cfm_per_ft2 = nil
  case boundary_condition
  when 'Outdoors'
    case surface_type
    when 'Door'
      infil_rate_cfm_per_ft2 = component_infil_rates_cfm_per_ft2[type]['opaque_door']
    when 'OverheadDoor'
      infil_rate_cfm_per_ft2 = component_infil_rates_cfm_per_ft2[type]['loading_dock_door']
    when 'GlassDoor'
      OpenStudio::logFree(OpenStudio::Info, "openstudio.Standards.Model", "For #{self.name}, assuming swinging_or_revolving_glass_door for infiltration calculation.")
      infil_rate_cfm_per_ft2 = component_infil_rates_cfm_per_ft2[type]['swinging_or_revolving_glass_door']
    when 'FixedWindow','OperableWindow'
      infil_rate_cfm_per_ft2 = component_infil_rates_cfm_per_ft2[type]['window']
    when 'Skylight','TubularDaylightDome','TubularDaylightDiffuser'
      infil_rate_cfm_per_ft2 = component_infil_rates_cfm_per_ft2[type]['skylight']
    end
  end
  if infil_rate_cfm_per_ft2.nil?
    OpenStudio::logFree(OpenStudio::Warn, "openstudio.Standards.Model", "For #{self.name}, could not determine surface type for infiltration, will not be included in calculation.")
    return comp_infil_rate_m3_per_s
  end
    
  # Area of the surface
  area_m2 = self.netArea
  area_ft2 = OpenStudio.convert(area_m2,'m^2','ft^2').get
  
  # Rate for this surface
  comp_infil_rate_cfm = area_ft2 * infil_rate_cfm_per_ft2

  comp_infil_rate_m3_per_s = OpenStudio.convert(comp_infil_rate_cfm,'cfm','m^3/s').get

  #OpenStudio::logFree(OpenStudio::Debug, "openstudio.Standards.Model", "......#{self.name}, infil = #{comp_infil_rate_cfm.round(2)} cfm @ rate = #{infil_rate_cfm_per_ft2} cfm/ft2, area = #{area_ft2.round} ft2.")
  
  return comp_infil_rate_m3_per_s
  
end

#reduce_area_by_percent_by_raising_sill(percent_reduction) ⇒ Object

Reduce the area of the subsurface by raising the sill height.

to reduce the area.

Parameters:

  • percent_reduction (Double) —

    the fractional amount



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# File 'lib/openstudio-standards/standards/Standards.SubSurface.rb', line 84

def reduce_area_by_percent_by_raising_sill(percent_reduction)

  mult = 1-percent_reduction
  
  # Calculate the original area
  area_original = self.netArea

  # Find the min and max z values
  min_z_val = 99999
  max_z_val = -99999
  self.vertices.each do |vertex|
    # Min z value
    if vertex.z < min_z_val
      min_z_val = vertex.z
    end
    # Max z value
    if vertex.z > max_z_val
      max_z_val = vertex.z
    end
  end
  
  # Calculate the window height
  height = max_z_val - min_z_val
  
  # Calculate the new sill height
  new_sill_z = max_z_val - (height * mult)    
  
  # Reset the z value of the lowest points
  new_vertices = []
  self.vertices.each do |vertex|
    new_x = vertex.x
    new_y = vertex.y
    new_z = vertex.z
    if new_z == min_z_val
      new_z = new_sill_z
    end
    new_vertices << OpenStudio::Point3d.new(new_x, new_y, new_z)
  end
  
  # Reset the vertices
  self.setVertices(new_vertices)
  
  # Compare the new area to the old for validation
  act_pct_red = 1.0 - (self.netArea / area_original)
  
  return true

end

#reduce_area_by_percent_by_shrinking_x(percent_reduction) ⇒ Object

Reduce the area of the subsurface by shrinking it in the x direction. Designed to work on skylights.

to reduce the area.

Parameters:

  • percent_reduction (Double) —

    the fractional amount



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# File 'lib/openstudio-standards/standards/Standards.SubSurface.rb', line 138

def reduce_area_by_percent_by_shrinking_x(percent_reduction)

  mult = 1-percent_reduction
  
  # Calculate the original area
  area_original = self.netArea

  # Find the min and max x values
  min_x_val = 99999
  max_x_val = -99999
  self.vertices.each do |vertex|
    # Min x value
    if vertex.x < min_x_val
      min_x_val = vertex.x
    end
    # Max x value
    if vertex.x > max_x_val
      max_x_val = vertex.x
    end
  end
  
  # Calculate the skylight width
  width = max_x_val - min_x_val
  
  # Calculate the new sill width
  new_width_x = max_x_val - (width * mult)    
  
  # Reset the z value of the lowest points
  new_vertices = []
  self.vertices.each do |vertex|
    new_x = vertex.x
    if new_x == min_x_val
      new_x = new_width_x
    end
    new_y = vertex.y
    new_z = vertex.z
    new_vertices << OpenStudio::Point3d.new(new_x, new_y, new_z)
  end
  
  # Reset the vertices
  self.setVertices(new_vertices)
  
  # Compare the new area to the old for validation
  act_pct_red = 1.0 - (self.netArea / area_original)
  
  return true

end