class DEER2020
This class holds methods that apply DEER
2020 to a given model. @ref [References::DEERMASControl]
Attributes
Public Class Methods
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.rb, line 7 def initialize @template = 'DEER 2020' load_standards_database end
Public Instance Methods
Determine if the standard has an exception for demand control ventilation when an energy recovery device is present. Unlike ASHRAE 90.1, Title 24 does not have an ERV exception to DCV. This method is a copy of what is in Standards.AirLoopHVAC.rb and ensures ERVs will not prevent DCV from being applied to DEER
models.
@param air_loop_hvac [OpenStudio::Model::AirLoopHVAC] air loop return [Boolean] returns true if required, false if not
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.AirLoopHVAC.rb, line 52 def air_loop_hvac_dcv_required_when_erv(air_loop_hvac) dcv_required_when_erv_present = true return dcv_required_when_erv_present end
@param air_loop_hvac [OpenStudio::Model::AirLoopHVAC] air loop @return [Array<Double>] [min_oa_without_economizer_cfm, min_oa_with_economizer_cfm]
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.AirLoopHVAC.rb, line 38 def air_loop_hvac_demand_control_ventilation_limits(air_loop_hvac) min_oa_without_economizer_cfm = 3000 min_oa_with_economizer_cfm = 0 return [min_oa_without_economizer_cfm, min_oa_with_economizer_cfm] end
Determine if a motorized OA damper is required Defaults to true for DEER
2020.
@param air_loop_hvac [OpenStudio::Model::AirLoopHVAC] air loop @param climate_zone [String] ASHRAE climate zone, e.g. ‘ASHRAE 169-2013-4A’ @return [Boolean] returns true if required, false if not
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.AirLoopHVAC.rb, line 31 def air_loop_hvac_motorized_oa_damper_required?(air_loop_hvac, climate_zone) motorized_oa_damper_required = true return motorized_oa_damper_required end
Determine if the system required supply air temperature (SAT) reset. Defaults to true for DEER
2020.
@param air_loop_hvac [OpenStudio::Model::AirLoopHVAC] air loop @param climate_zone [String] ASHRAE climate zone, e.g. ‘ASHRAE 169-2013-4A’ @return [Boolean] returns true if required, false if not
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.AirLoopHVAC.rb, line 10 def air_loop_hvac_supply_air_temperature_reset_required?(air_loop_hvac, climate_zone) is_sat_reset_required = true return is_sat_reset_required end
Determine if a system’s fans must shut off when not required. Per ASHRAE 90.1 section 6.4.3.3, HVAC systems are required to have off-hour controls
@param air_loop_hvac [OpenStudio::Model::AirLoopHVAC] air loop @return [Boolean] returns true if required, false if not
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.AirLoopHVAC.rb, line 20 def air_loop_hvac_unoccupied_fan_shutoff_required?(air_loop_hvac) shutoff_required = true return shutoff_required end
Determines whether there is a requirement to have a VSD or some other method to reduce fan power at low part load ratios.
@param fan_variable_volume [OpenStudio::Model::FanVariableVolume] variable volume fan object @return [Boolean] returns true if required, false if not
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.FanVariableVolume.rb, line 8 def fan_variable_volume_part_load_fan_power_limitation?(fan_variable_volume) part_load_control_required = false # Check if the fan is on a multizone or single zone system. # If not on an AirLoop (for example, in unitary system or zone equipment), assumed to be a single zone fan mz_fan = false if fan_variable_volume.airLoopHVAC.is_initialized air_loop = fan_variable_volume.airLoopHVAC.get mz_fan = air_loop_hvac_multizone_vav_system?(air_loop) end # No part load fan power control is required for single zone VAV systems unless mz_fan OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.FanVariableVolume', "For #{fan_variable_volume.name}: No part load fan power control is required for single zone VAV systems.") return part_load_control_required end # Assume static pressure reset for all multi-zone fans part_load_control_required = true return part_load_control_required end
Loads the openstudio standards dataset for this standard.
@param data_directories [Array<String>] array of file paths that contain standards data @return [Hash] a hash of standards data
DEER#load_standards_database
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.rb, line 16 def load_standards_database(data_directories = []) super([__dir__] + data_directories) end
Determines the method used to extend the daylighted area horizontally next to a window. If the method is ‘fixed’, 2 ft is added to the width of each window. If the method is ‘proportional’, a distance equal to half of the head height of the window is added. If the method is ‘none’, no additional width is added.
@return [String] returns ‘fixed’ or ‘proportional’
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.Space.rb, line 11 def space_daylighted_area_window_width(space) method = 'proportional' return method end
Determine if the space requires daylighting controls for toplighting, primary sidelighting, and secondary sidelighting. Defaults to false for all types.
@param space [OpenStudio::Model::Space] the space in question @param areas [Hash] a hash of daylighted areas @return [Array<Bool>] req_top_ctrl, req_pri_ctrl, req_sec_ctrl
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.Space.rb, line 23 def space_daylighting_control_required?(space, areas) req_top_ctrl = true req_pri_ctrl = true req_sec_ctrl = true # Get the LPD of the space space_lpd_w_per_m2 = space.lightingPowerPerFloorArea # Primary Sidelighting # Check if the primary sidelit area contains less than 120W of lighting if areas['primary_sidelighted_area'] == 0.0 OpenStudio.logFree(OpenStudio::Debug, 'openstudio.model.Space', "For #{space.name}, primary sidelighting control not required because primary sidelighted area = 0ft2.") req_pri_ctrl = false elsif areas['primary_sidelighted_area'] * space_lpd_w_per_m2 < 120.0 OpenStudio.logFree(OpenStudio::Info, 'openstudio.model.Space', "For #{space.name}, primary sidelighting control not required because less than 120W of lighting are present in the primary daylighted area per 130.1(d) exception 3 T24-2019.") req_pri_ctrl = false else # Check the size of the windows if areas['total_window_area'] < OpenStudio.convert(24.0, 'ft^2', 'm^2').get OpenStudio.logFree(OpenStudio::Info, 'openstudio.model.Space', "For #{space.name}, primary sidelighting control not required because there are less than 24ft2 of window per 130.1(d) exception 4 T24-2019.") req_pri_ctrl = false end end # Secondary Sidelighting # Check if the primary and secondary sidelit areas contains less than 120W of lighting if areas['secondary_sidelighted_area'] == 0.0 OpenStudio.logFree(OpenStudio::Debug, 'openstudio.model.Space', "For #{space.name}, secondary sidelighting control not required because secondary sidelighted area = 0ft2.") req_sec_ctrl = false elsif (areas['primary_sidelighted_area'] + areas['secondary_sidelighted_area']) * space_lpd_w_per_m2 < 120 OpenStudio.logFree(OpenStudio::Info, 'openstudio.model.Space', "For #{space.name}, secondary sidelighting control not required because less than 120W of lighting are present in the combined primary and secondary daylighted areas per 5.5.3 prescriptive exception 1 T24-2019 NonRes ACM.") req_sec_ctrl = false else # Check the size of the windows if areas['total_window_area'] < OpenStudio.convert(24.0, 'ft^2', 'm^2').get OpenStudio.logFree(OpenStudio::Info, 'openstudio.model.Space', "For #{space.name}, secondary sidelighting control not required because there are less than 24ft2 of window per 130.1(d) exception 4 T24-2019.") req_sec_ctrl = false end end # Toplighting # Check if the toplit area contains less than 120W of lighting if areas['toplighted_area'] == 0.0 OpenStudio.logFree(OpenStudio::Debug, 'openstudio.model.Space', "For #{space.name}, toplighting control not required because toplighted area = 0ft2.") req_top_ctrl = false elsif areas['toplighted_area'] * space_lpd_w_per_m2 < 120 OpenStudio.logFree(OpenStudio::Info, 'openstudio.model.Space', "For #{space.name}, toplighting control not required because less than 120W of lighting are present in the toplighted area per 130.1(d) exception 3 T24-2019.") req_top_ctrl = false end return [req_top_ctrl, req_pri_ctrl, req_sec_ctrl] end
Determine the fraction controlled by each sensor and which window each sensor should go near.
@param space [OpenStudio::Model::Space] space object @param areas [Hash] a hash of daylighted areas @param sorted_windows [Hash] a hash of windows, sorted by priority @param sorted_skylights [Hash] a hash of skylights, sorted by priority @param req_top_ctrl [Boolean] if toplighting controls are required @param req_pri_ctrl [Boolean] if primary sidelighting controls are required @param req_sec_ctrl [Boolean] if secondary sidelighting controls are required @return [Array] array of 4 items
[sensor 1 fraction, sensor 2 fraction, sensor 1 window, sensor 2 window]
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.Space.rb, line 87 def space_daylighting_fractions_and_windows(space, areas, sorted_windows, sorted_skylights, req_top_ctrl, req_pri_ctrl, req_sec_ctrl) sensor_1_frac = 0.0 sensor_2_frac = 0.0 sensor_1_window = nil sensor_2_window = nil # Get the area of the space space_area_m2 = space.floorArea if req_top_ctrl && req_pri_ctrl && req_sec_ctrl # Sensor 1 controls toplighted area sensor_1_frac = areas['toplighted_area'] / space_area_m2 sensor_1_window = sorted_skylights[0] # Sensor 2 controls primary + secondary area sensor_2_frac = (areas['primary_sidelighted_area'] + areas['secondary_sidelighted_area']) / space_area_m2 sensor_2_window = sorted_windows[0] elsif !req_top_ctrl && req_pri_ctrl && req_sec_ctrl # Sensor 1 controls primary area sensor_1_frac = areas['primary_sidelighted_area'] / space_area_m2 sensor_1_window = sorted_windows[0] # Sensor 2 controls secondary area sensor_2_frac = (areas['secondary_sidelighted_area'] / space_area_m2) sensor_2_window = sorted_windows[0] elsif req_top_ctrl && !req_pri_ctrl && req_sec_ctrl # Sensor 1 controls toplighted area sensor_1_frac = areas['toplighted_area'] / space_area_m2 sensor_1_window = sorted_skylights[0] # Sensor 2 controls secondary area sensor_2_frac = (areas['secondary_sidelighted_area'] / space_area_m2) sensor_2_window = sorted_windows[0] elsif req_top_ctrl && !req_pri_ctrl && !req_sec_ctrl # Sensor 1 controls toplighted area sensor_1_frac = areas['toplighted_area'] / space_area_m2 sensor_1_window = sorted_skylights[0] elsif !req_top_ctrl && req_pri_ctrl && !req_sec_ctrl # Sensor 1 controls primary area sensor_1_frac = areas['primary_sidelighted_area'] / space_area_m2 sensor_1_window = sorted_windows[0] elsif !req_top_ctrl && !req_pri_ctrl && req_sec_ctrl # Sensor 1 controls secondary area sensor_1_frac = areas['secondary_sidelighted_area'] / space_area_m2 sensor_1_window = sorted_windows[0] end return [sensor_1_frac, sensor_2_frac, sensor_1_window, sensor_2_window] end
Determine the area and occupancy level limits for demand control ventilation.
@param thermal_zone [OpenStudio::Model::ThermalZone] the thermal zone @return [Array<Double>] the minimum area, in m^2 and the minimum occupancy density in m^2/person. Returns nil if there is no requirement.
# File lib/openstudio-standards/standards/deer/deer_2020/deer_2020.ThermalZone.rb, line 11 def thermal_zone_demand_control_ventilation_limits(thermal_zone) min_area_ft2 = 150 min_ft2_per_occ = 40 # Convert to SI min_area_m2 = OpenStudio.convert(min_area_ft2, 'ft^2', 'm^2').get min_m2_per_occ = OpenStudio.convert(min_ft2_per_occ, 'ft^2', 'm^2').get return [min_area_m2, min_m2_per_occ] end