Non-transient dwelling unit energy recovery ventilation

data/standards/manage_OpenStudio_Standards.rb

@@ -98,6 +98,8 @@ def unique_properties(sheet_name)
            ['template', 'fluid_type', 'fuel_type', 'condensing', 'condensing_control', 'minimum_capacity', 'maximum_capacity', 'start_date', 'end_date']
          when 'chillers'
            ['template', 'cooling_type', 'condenser_type', 'compressor_type', 'absorption_type', 'variable_speed_drive', 'minimum_capacity', 'maximum_capacity', 'start_date', 'end_date']
+         when 'furnaces'
+           ['template', 'minimum_capacity', 'maximum_capacity', 'start_date', 'end_date']
          when 'heat_rejection'
            ['template', 'equipment_type', 'fan_type', 'start_date', 'end_date']
          when 'water_source_heat_pumps'
@@ -143,7 +145,7 @@ def unique_properties(sheet_name)
          when 'climate_zones'
            ['name', 'standard']
          when 'energy_recovery'
-           ['template', 'climate_zone', 'under_8000_hours']
+           ['template', 'climate_zone', 'under_8000_hours', 'nontransient_dwelling', 'err_basis']
          when 'space_types_lighting_control'
            ['template', 'building_type', 'space_type']
          else
@@ -345,6 +347,7 @@ def export_spreadsheet_to_json(spreadsheet_titles, dataset_type: 'os_stds')
   bool_cols << 'hx'
   bool_cols << 'data_center'
   bool_cols << 'under_8000_hours'
+  bool_cols << 'nontransient_dwelling'
   bool_cols << 'u_value_includes_interior_film_coefficient'
   bool_cols << 'u_value_includes_exterior_film_coefficient'
 

lib/openstudio-standards/prototypes/ashrae_90_1/ashrae_90_1_2016/ashrae_90_1_2016.Model.rb

@@ -278,7 +278,7 @@ def model_add_lights_shutoff(model)
     business_sensor.setName('Business_Sensor')
     business_sensor_name = business_sensor.name.to_s
 
-    zones.each do |zone|
+    zones.sort.each do |zone|
       spaces = zone.spaces
       if spaces.length != 1
         puts 'warning, there are more than one spaces in the zone, need to confirm the implementation'

lib/openstudio-standards/prototypes/ashrae_90_1/ashrae_90_1_2019/ashrae_90_1_2019.Model.rb

@@ -278,7 +278,7 @@ def model_add_lights_shutoff(model)
     business_sensor.setName('Business_Sensor')
     business_sensor_name = business_sensor.name.to_s
 
-    zones.each do |zone|
+    zones.sort.each do |zone|
       spaces = zone.spaces
       if spaces.length != 1
         puts 'warning, there are more than one spaces in the zone, need to confirm the implementation'

lib/openstudio-standards/prototypes/common/buildings/Prototype.HighRiseApartment.rb

@@ -112,6 +112,8 @@ def add_door_infiltration(climate_zone, model)
 
   def model_update_fan_efficiency(model)
     model.getFanOnOffs.sort.each do |fan_onoff|
+      next if fan_onoff.name.get.to_s.include?('ERV')
+
       fan_onoff.setFanEfficiency(0.53625)
       fan_onoff.setMotorEfficiency(0.825)
     end

lib/openstudio-standards/prototypes/common/objects/Prototype.HeatExchangerAirToAirSensibleAndLatent.rb

@@ -86,4 +86,41 @@ def heat_exchanger_air_to_air_sensible_and_latent_apply_prototype_efficiency(hea
 
     return true
   end
+
+  # Set sensible and latent effectiveness at 100 and 75 heating and cooling airflow;
+  # The values are calculated by using ERR, which is introduced in 90.1-2016 Addendum CE
+  #
+  # This function is only used for nontransient dwelling units (Mid-rise and High-rise Apartment)
+  # @param [OpenStudio::Model::HeatExchangerAirToAirSensibleAndLatent] heat exchanger air to air sensible and latent
+  # @param [String] err
+  # @param [String] err basis (Cooling/Heating)
+  # @param [String] climate zone
+  def heat_exchanger_air_to_air_sensible_and_latent_apply_prototype_efficiency_err(heat_exchanger_air_to_air_sensible_and_latent, err, basis, climate_zone)
+    # Assumed to be sensible and latent at all flow
+    if err.nil?
+      full_htg_sens_eff = 0.0
+      full_htg_lat_eff = 0.0
+      part_htg_sens_eff = 0.0
+      part_htg_lat_eff = 0.0
+      full_cool_sens_eff = 0.0
+      full_cool_lat_eff = 0.0
+      part_cool_sens_eff = 0.0
+      part_cool_lat_eff = 0.0
+    else
+      err = enthalpy_recovery_ratio_design_to_typical_adjustment(err, climate_zone)
+      full_htg_sens_eff, full_htg_lat_eff, part_htg_sens_eff, part_htg_lat_eff, full_cool_sens_eff, full_cool_lat_eff, part_cool_sens_eff, part_cool_lat_eff = heat_exchanger_air_to_air_sensible_and_latent_enthalpy_recovery_ratio_to_effectiveness(err, basis)
+    end
+
+    heat_exchanger_air_to_air_sensible_and_latent.setSensibleEffectivenessat100HeatingAirFlow(full_htg_sens_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setLatentEffectivenessat100HeatingAirFlow(full_htg_lat_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setSensibleEffectivenessat75HeatingAirFlow(part_htg_sens_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setLatentEffectivenessat75HeatingAirFlow(part_htg_lat_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setSensibleEffectivenessat100CoolingAirFlow(full_cool_sens_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setLatentEffectivenessat100CoolingAirFlow(full_cool_lat_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setSensibleEffectivenessat75CoolingAirFlow(part_cool_sens_eff)
+    heat_exchanger_air_to_air_sensible_and_latent.setLatentEffectivenessat75CoolingAirFlow(part_cool_lat_eff)
+
+    OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.HeatExchangerSensLat', "For #{heat_exchanger_air_to_air_sensible_and_latent.name}: Set sensible and latent effectiveness calculated by using ERR.")
+    return true
+  end
 end

lib/openstudio-standards/prototypes/common/objects/Prototype.Model.rb

@@ -1583,10 +1583,61 @@ def model_apply_prototype_hvac_assumptions(model, building_type, climate_zone)
   #
   # @param model [OpenStudio::Model::Model] the model
   def model_apply_prototype_hvac_efficiency_adjustments(model)
+    building_data = model_get_building_climate_zone_and_building_type(model)
+    building_type = building_data['building_type']
+    climate_zone = building_data['climate_zone']
+
     # ERVs
-    # Applies the DOE Prototype Building assumption that ERVs use
-    # enthalpy wheels and therefore exceed the minimum effectiveness specified by 90.1
-    model.getHeatExchangerAirToAirSensibleAndLatents.each { |obj| heat_exchanger_air_to_air_sensible_and_latent_apply_prototype_efficiency(obj) }
+    if building_type == 'MidriseApartment' || building_type == 'HighriseApartment'
+      # Use standalone ERV in dwelling units to provide OA
+      # Loads are met by mechanical cooling and the heating system with a cycling fan
+      model.getAirLoopHVACs.each do |air_loop_hvac|
+        # Find out if air loop has an ERV (i.e. if heat recovery is required)
+        has_erv = false
+        has_erv = true if air_loop_hvac_energy_recovery?(air_loop_hvac)
+
+        serves_res_spc = false
+
+        air_loop_hvac.thermalZones.each do |zone|
+          next unless thermal_zone_residential?(zone)
+
+          model_add_residential_erv(model, zone, climate_zone, has_erv)
+
+          # Shut-off air loop level OA intake
+          oa_controller = air_loop_hvac.airLoopHVACOutdoorAirSystem.get.getControllerOutdoorAir
+          oa_controller.setMinimumOutdoorAirSchedule(model.alwaysOffDiscreteSchedule)
+
+          serves_res_spc = true
+        end
+
+        if has_erv & serves_res_spc
+          # Remove air loop ERV
+          air_loop_hvac_remove_erv(air_loop_hvac)
+        elsif has_erv
+          # Apply regular adjustment if the ERV doesn't serve a residential space
+          oa_sys = nil
+          if air_loop_hvac.airLoopHVACOutdoorAirSystem.is_initialized
+            oa_sys = air_loop_hvac.airLoopHVACOutdoorAirSystem.get
+          else
+            OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{air_loop_hvac.name}, ERV cannot be removed because the system has no OA intake.")
+            return false
+          end
+
+          # Get the existing ERV or create an ERV and add it to the OA system
+          oa_sys.oaComponents.each do |oa_comp|
+            if oa_comp.to_HeatExchangerAirToAirSensibleAndLatent.is_initialized
+              erv = oa_comp.to_HeatExchangerAirToAirSensibleAndLatent.get
+              heat_exchanger_air_to_air_sensible_and_latent_apply_prototype_efficiency(erv)
+            end
+          end
+        end
+      end
+    else
+      # Applies the DOE Prototype Building assumption that ERVs use
+      # enthalpy wheels and therefore exceed the minimum effectiveness specified by 90.1
+      model.getHeatExchangerAirToAirSensibleAndLatents.each { |obj| heat_exchanger_air_to_air_sensible_and_latent_apply_prototype_efficiency(obj) }
+    end
+
     return true
   end
 

lib/openstudio-standards/prototypes/common/objects/Prototype.hvac_systems.rb

@@ -6435,4 +6435,181 @@ def model_add_swh_end_uses_by_spaceonly(model, space, swh_loop)
     swh_loop.addDemandBranchForComponent(swh_connection)
     return water_fixture
   end
+
+  # Add a residential ERV: standalone ERV that operates to provide OA,
+  # use in conjuction witha system that having mechanical cooling and
+  # a heating coil
+  #
+  # @param model [OpenStudio::Model::Model] OpenStudio Model object
+  # @param thermal_zone [OpenStudio::Model::ThermalZone] OpenStudio ThermalZone object
+  # @param climate_zone [String] Climate zone
+  # @param energy_recovery [Boolean] Indicates if the ERV is to recover energy, if false, only provides OA
+  # @return [OpenStudio::Model::ZoneHVACEnergyRecoveryVentilator] Standalone ERV
+  def model_add_residential_erv(model,
+                                thermal_zone,
+                                climate_zone,
+                                energy_recovery,
+                                min_oa_flow_m3_per_s_per_m2: nil)
+
+    OpenStudio.logFree(OpenStudio::Info, 'openstudio.Model.Model', "Adding standalone ERV for #{thermal_zone.name}.")
+
+    # Exception 3 to 6.5.6.1.1
+    case template
+      when '90.1-2019'
+        case climate_zone
+          when 'ASHRAE 169-2006-0A',
+            'ASHRAE 169-2006-0B',
+            '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',
+            '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 169-2013-0A',
+            'ASHRAE 169-2013-0B',
+            'ASHRAE 169-2013-1A',
+            'ASHRAE 169-2013-1B',
+            'ASHRAE 169-2013-2A',
+            'ASHRAE 169-2013-2B',
+            'ASHRAE 169-2013-3A',
+            'ASHRAE 169-2013-3B',
+            'ASHRAE 169-2013-3C',
+            'ASHRAE 169-2013-4A',
+            'ASHRAE 169-2013-4B',
+            'ASHRAE 169-2013-4C',
+            'ASHRAE 169-2013-5A',
+            'ASHRAE 169-2013-5B',
+            'ASHRAE 169-2013-5C'
+            if thermal_zone_floor_area(thermal_zone) <= OpenStudio.convert(500, 'ft^2', 'm^2').get
+              energy_recovery = false
+              OpenStudio.logFree(OpenStudio::Info, 'openstudio.Model.Model', "Energy recovery will not be modeled for the ERV serving #{thermal_zone.name}.")
+            end
+        end
+    end
+
+    # Determine ERR and design basis when energy recovery is required
+    #
+    # err = nil will trigger an ERV with no effectiveness that only provides OA
+    err = nil
+    if energy_recovery
+      case template
+        when '90.1-2019'
+          search_criteria = {
+            'template' => template,
+            'climate_zone' => climate_zone,
+            'under_8000_hours' => false,
+            'nontransient_dwelling' => true
+          }
+        else
+          search_criteria = {
+            'template' => template,
+            'climate_zone' => climate_zone,
+            'under_8000_hours' => false
+          }
+      end
+
+      erv_err = model_find_object(standards_data['energy_recovery'], search_criteria)
+
+      # Extract ERR from data lookup
+      if !erv_err.nil?
+        if erv_err['err'].nil? & erv_err['err_basis'].nil?
+          # If not included in the data, an enthalpy
+          # recovery ratio (ERR) of 50% is used
+          err = 0.5
+          case climate_zone
+            when 'ASHRAE 169-2006-6B',
+              'ASHRAE 169-2013-6B',
+              'ASHRAE 169-2006-7A',
+              'ASHRAE 169-2013-7A',
+              'ASHRAE 169-2006-7B',
+              'ASHRAE 169-2013-7B',
+              'ASHRAE 169-2006-8A',
+              'ASHRAE 169-2013-8A',
+              'ASHRAE 169-2006-8B',
+              'ASHRAE 169-2013-8B'
+              err_basis = 'heating'
+            else
+              err_basis = 'cooling'
+          end
+        else
+          err_basis = erv_err['err_basis'].downcase
+          err = erv_err['err']
+        end
+      end
+    end
+
+    # Create fans
+    #
+    # Fan power:
+    # No energy recovery = 0.806 W/cfm
+    # Energy recovery = 0.934 W/cfm
+    supply_fan = create_fan_by_name(model,
+                                    'ERV_Supply_Fan',
+                                    fan_name: "#{thermal_zone.name} ERV Supply Fan")
+    exhaust_fan = create_fan_by_name(model,
+                                     'ERV_Supply_Fan',
+                                     fan_name: "#{thermal_zone.name} ERV Exhaust Fan")
+    supply_fan.setMotorEfficiency(0.48)
+    exhaust_fan.setMotorEfficiency(0.48)
+    supply_fan.setFanTotalEfficiency(0.303158)
+    exhaust_fan.setFanTotalEfficiency(0.303158)
+    if energy_recovery
+      supply_fan.setPressureRise(270.64755)
+      exhaust_fan.setPressureRise(270.64755)
+    else
+      supply_fan.setPressureRise(233.6875)
+      exhaust_fan.setPressureRise(233.6875)
+    end
+
+    # Create ERV Controller
+    erv_controller = OpenStudio::Model::ZoneHVACEnergyRecoveryVentilatorController.new(model)
+    erv_controller.setName("#{thermal_zone.name} ERV Controller")
+    erv_controller.setControlHighIndoorHumidityBasedonOutdoorHumidityRatio(false)
+
+    # Create heat exchanger
+    heat_exchanger = OpenStudio::Model::HeatExchangerAirToAirSensibleAndLatent.new(model)
+    heat_exchanger.setName("#{thermal_zone.name} ERV HX")
+    heat_exchanger.setSupplyAirOutletTemperatureControl(false)
+    heat_exchanger.setHeatExchangerType('Rotary')
+    heat_exchanger.setEconomizerLockout(false)
+    heat_exchanger.setFrostControlType('ExhaustOnly')
+    heat_exchanger.setThresholdTemperature(-23.3)
+    heat_exchanger.setInitialDefrostTimeFraction(0.167)
+    heat_exchanger.setRateofDefrostTimeFractionIncrease(1.44)
+    heat_exchanger.setAvailabilitySchedule(model_add_schedule(model, 'Always On - No DD'))
+    heat_exchanger_air_to_air_sensible_and_latent_apply_prototype_efficiency_err(heat_exchanger, err, err_basis, climate_zone)
+
+    erv = OpenStudio::Model::ZoneHVACEnergyRecoveryVentilator.new(model, heat_exchanger, supply_fan, exhaust_fan)
+    erv.setName("#{thermal_zone.name} ERV")
+
+    erv.setController(erv_controller)
+    erv.addToThermalZone(thermal_zone)
+
+    # Set OA requirements; Assumes a default of 55 cfm
+    if min_oa_flow_m3_per_s_per_m2.nil?
+      erv.setSupplyAirFlowRate(OpenStudio.convert(55.0, 'cfm', 'm^3/s').get)
+      erv.setExhaustAirFlowRate(OpenStudio.convert(55.0, 'cfm', 'm^3/s').get)
+    else
+      erv.setVentilationRateperUnitFloorArea(min_oa_flow_m3_per_s_per_m2)
+    end
+
+    # Ensure the ERV takes priority, so ventilation load is included when treated by other zonal systems
+    # From EnergyPlus I/O reference:
+    # "For situations where one or more equipment types has limited capacity or limited control capability, order the
+    #  sequence so that the most controllable piece of equipment runs last. For example, with a dedicated outdoor air
+    #  system (DOAS), the air terminal for the DOAS should be assigned Heating Sequence = 1 and Cooling Sequence = 1.
+    #  Any other equipment should be assigned sequence 2 or higher so that it will see the net load after the DOAS air
+    #  is added to the zone."
+    thermal_zone.setCoolingPriority(erv.to_ModelObject.get, 1)
+    thermal_zone.setHeatingPriority(erv.to_ModelObject.get, 1)
+
+    return erv
+  end
 end

lib/openstudio-standards/standards/Standards.AirLoopHVAC.rb

@@ -1567,6 +1567,27 @@ def air_loop_hvac_energy_recovery_ventilator_heat_exchanger_type(air_loop_hvac)
     return heat_exchanger_type
   end
 
+  def air_loop_hvac_remove_erv(air_loop_hvac)
+    # Get the OA system
+    oa_sys = nil
+    if air_loop_hvac.airLoopHVACOutdoorAirSystem.is_initialized
+      oa_sys = air_loop_hvac.airLoopHVACOutdoorAirSystem.get
+    else
+      OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.AirLoopHVAC', "For #{air_loop_hvac.name}, ERV cannot be removed because the system has no OA intake.")
+      return false
+    end
+
+    # Get the existing ERV or create an ERV and add it to the OA system
+    oa_sys.oaComponents.each do |oa_comp|
+      if oa_comp.to_HeatExchangerAirToAirSensibleAndLatent.is_initialized
+        erv = oa_comp.to_HeatExchangerAirToAirSensibleAndLatent.get
+        erv.remove
+      end
+    end
+
+    return true
+  end
+
   # Add an ERV to this airloop
   #
   # @param (see #economizer_required?)