Merge pull request #1712 from NREL/mj8_ventilation

MJ8 infiltration/ventilation

HPXMLtoOpenStudio/measure.xml

@@ -3,8 +3,8 @@
   <schema_version>3.1</schema_version>
   <name>hpxm_lto_openstudio</name>
   <uid>b1543b30-9465-45ff-ba04-1d1f85e763bc</uid>
-  <version_id>235ba31f-08b7-42da-9524-674d6b212611</version_id>
-  <version_modified>2024-05-18T14:58:34Z</version_modified>
+  <version_id>a3010ed3-bfec-4d89-b425-0ec627863167</version_id>
+  <version_modified>2024-05-18T15:40:55Z</version_modified>
   <xml_checksum>D8922A73</xml_checksum>
   <class_name>HPXMLtoOpenStudio</class_name>
   <display_name>HPXML to OpenStudio Translator</display_name>
@@ -387,7 +387,7 @@
       <filename>hvac_sizing.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>828250E9</checksum>
+      <checksum>8526074F</checksum>
     </file>
     <file>
       <filename>lighting.rb</filename>
@@ -639,7 +639,7 @@
       <filename>test_defaults.rb</filename>
       <filetype>rb</filetype>
       <usage_type>test</usage_type>
-      <checksum>8EEC2D8E</checksum>
+      <checksum>A84FE910</checksum>
     </file>
     <file>
       <filename>test_enclosure.rb</filename>
@@ -669,7 +669,7 @@
       <filename>test_hvac_sizing.rb</filename>
       <filetype>rb</filetype>
       <usage_type>test</usage_type>
-      <checksum>D5AC9590</checksum>
+      <checksum>BA43A919</checksum>
     </file>
     <file>
       <filename>test_lighting.rb</filename>

HPXMLtoOpenStudio/resources/hvac_sizing.rb

@@ -58,6 +58,7 @@ def self.calculate(runner, weather, hpxml_bldg, hvac_systems, update_hpxml: true
       apply_fractions_load_served(hvac_heating, hvac_loads, frac_zone_heat_load_served, frac_zone_cool_load_served)
       apply_hvac_duct_loads_heating(mj, zone, hvac_loads, all_zone_loads[zone], all_space_loads, hvac_heating, hpxml_bldg)
       apply_hvac_duct_loads_cooling(mj, zone, hvac_loads, all_zone_loads[zone], all_space_loads, hvac_cooling, hpxml_bldg, weather)
+      apply_hvac_cfis_loads(mj, hvac_loads, all_zone_loads[zone], hvac_heating, hvac_cooling, hpxml_bldg)
 
       # Calculate HVAC equipment sizes
       hvac_sizings = HVACSizingValues.new
@@ -1268,29 +1269,51 @@ def self.process_load_infiltration_ventilation(mj, hpxml_bldg, all_zone_loads, a
     # Calculate ventilation airflow rates
     q_unb_cfm, q_bal_cfm, q_preheat, q_precool, q_recirc, bal_sens_eff, bal_lat_eff = get_ventilation_data(hpxml_bldg)
 
-    # Calculate adjusted infiltration cfm (combined with ventilation)
-    infil_cfm_heat = (icfm_heat**1.5 + q_unb_cfm**1.5)**0.67 - q_unb_cfm
-    infil_cfm_cool = (icfm_cool**1.5 + q_unb_cfm**1.5)**0.67 - q_unb_cfm
+    # Calculate net infiltration cfm (NCFM; infiltration combined with unbalanced ventilation)
+    if q_unb_cfm == 0
+      # Neutral pressure, so NCFM = ICFM
+      infil_ncfm_heat = icfm_heat
+      infil_ncfm_cool = icfm_cool
+    elsif q_unb_cfm > 0
+      # Negative pressure, so NCFM = (ICFM^1.5 + CFMimb^1.5)^0.67
+      infil_ncfm_heat = (icfm_heat**1.5 + q_unb_cfm**1.5)**0.67
+      infil_ncfm_cool = (icfm_cool**1.5 + q_unb_cfm**1.5)**0.67
+    else
+      if icfm_heat < q_unb_cfm.abs
+        # Dominating positive pressure, so NCFM = 0
+        infil_ncfm_heat = 0.0
+      else
+        # Mitigating positive pressure, so NCFM = (ICFM^1.5 - ABS(CFMimb)^1.5)^0.67
+        infil_ncfm_heat = (icfm_heat**1.5 - q_unb_cfm.abs**1.5)**0.67
+      end
+      if icfm_cool < q_unb_cfm.abs
+        # Dominating positive pressure, so NCFM = 0
+        infil_ncfm_cool = 0.0
+      else
+        # Mitigating positive pressure, so NCFM = (ICFM^1.5 - ABS(CFMimb)^1.5)^0.67
+        infil_ncfm_cool = (icfm_cool**1.5 - q_unb_cfm.abs**1.5)**0.67
+      end
+    end
 
-    hpxml_bldg.additional_properties.infil_heat_cfm = infil_cfm_heat
-    hpxml_bldg.additional_properties.infil_cool_cfm = infil_cfm_cool
+    hpxml_bldg.additional_properties.infil_heat_cfm = infil_ncfm_heat
+    hpxml_bldg.additional_properties.infil_cool_cfm = infil_ncfm_cool
 
     # Infiltration load
-    bldg_Heat_Infil = 1.1 * mj.acf * infil_cfm_heat * mj.htd
-    bldg_Cool_Infil_Sens = 1.1 * mj.acf * infil_cfm_cool * mj.ctd
-    bldg_Cool_Infil_Lat = 0.68 * mj.acf * infil_cfm_cool * mj.cool_design_grains
+    bldg_Heat_Infil = 1.1 * mj.acf * infil_ncfm_heat * mj.htd
+    bldg_Cool_Infil_Sens = 1.1 * mj.acf * infil_ncfm_cool * mj.ctd
+    bldg_Cool_Infil_Lat = 0.68 * mj.acf * infil_ncfm_cool * mj.cool_design_grains
 
     # Calculate vent cfm
-    vent_cfm_heat = q_unb_cfm + q_bal_cfm
+    vent_cfm_heat = q_bal_cfm
     vent_cfm_cool = vent_cfm_heat
 
     hpxml_bldg.additional_properties.vent_heat_cfm = vent_cfm_heat
     hpxml_bldg.additional_properties.vent_cool_cfm = vent_cfm_cool
 
     # Calculate vent cfm incorporating sens/lat effectiveness, preheat/precool, and recirc
-    vent_cfm_heat = q_unb_cfm + q_bal_cfm * (1.0 - bal_sens_eff) - q_preheat - q_recirc
-    vent_cfm_cool_sens = q_unb_cfm + q_bal_cfm * (1.0 - bal_sens_eff) - q_precool - q_recirc
-    vent_cfm_cool_lat = q_unb_cfm + q_bal_cfm * (1.0 - bal_lat_eff) - q_recirc
+    vent_cfm_heat = q_bal_cfm * (1.0 - bal_sens_eff) - q_preheat - q_recirc
+    vent_cfm_cool_sens = q_bal_cfm * (1.0 - bal_sens_eff) - q_precool - q_recirc
+    vent_cfm_cool_lat = q_bal_cfm * (1.0 - bal_lat_eff) - q_recirc
 
     bldg_Heat_Vent = 1.1 * mj.acf * vent_cfm_heat * mj.htd
     bldg_Cool_Vent_Sens = 1.1 * mj.acf * vent_cfm_cool_sens * mj.ctd
@@ -1686,6 +1709,44 @@ def self.apply_hvac_duct_loads_cooling(mj, zone, hvac_loads, zone_loads, all_spa
     end
   end
 
+  def self.apply_hvac_cfis_loads(mj, hvac_loads, zone_loads, hvac_heating, hvac_cooling, hpxml_bldg)
+    '''
+    CFIS Ventilation Loads
+    '''
+    if (not hvac_heating.nil?) && (not hvac_heating.distribution_system.nil?)
+      hvac_distribution = hvac_heating.distribution_system
+    elsif (not hvac_cooling.nil?) && (not hvac_cooling.distribution_system.nil?)
+      hvac_distribution = hvac_cooling.distribution_system
+    end
+    return if hvac_distribution.nil?
+
+    vent_mech_cfis = hpxml_bldg.ventilation_fans.find { |vent_mech| vent_mech.fan_type == HPXML::MechVentTypeCFIS && vent_mech.distribution_system_idref == hvac_distribution.id }
+    return if vent_mech_cfis.nil?
+
+    vent_cfm = vent_mech_cfis.total_unit_flow_rate
+
+    # Note: These are system loads, not space loads
+    heat_load = 1.1 * mj.acf * vent_cfm * mj.htd
+    cool_sens_load = 1.1 * mj.acf * vent_cfm * mj.ctd
+    cool_lat_load = 0.68 * mj.acf * vent_cfm * mj.cool_design_grains
+
+    hvac_loads.Heat_Vent += heat_load
+    hvac_loads.Heat_Tot += heat_load
+    hvac_loads.Cool_Vent_Sens += cool_sens_load
+    hvac_loads.Cool_Sens += cool_sens_load
+    hvac_loads.Cool_Vent_Lat += cool_lat_load
+    hvac_loads.Cool_Lat += cool_lat_load
+    hvac_loads.Cool_Tot += cool_sens_load + cool_lat_load
+
+    zone_loads.Heat_Vent += heat_load
+    zone_loads.Heat_Tot += heat_load
+    zone_loads.Cool_Vent_Sens += cool_sens_load
+    zone_loads.Cool_Sens += cool_sens_load
+    zone_loads.Cool_Vent_Lat += cool_lat_load
+    zone_loads.Cool_Lat += cool_lat_load
+    zone_loads.Cool_Tot += cool_sens_load + cool_lat_load
+  end
+
   def self.apply_hvac_equipment_adjustments(mj, runner, hvac_sizings, weather, hvac_heating, hvac_cooling, hvac_system, hpxml_bldg)
     '''
     Equipment Adjustments
@@ -2604,7 +2665,7 @@ def self.process_heat_pump_adjustment(mj, runner, hvac_sizings, weather, hvac_he
   end
 
   def self.get_ventilation_data(hpxml_bldg)
-    # If CFIS w/ supplemental fan, assume air handler is running most of the hour and can provide
+    # If CFIS w/ supplemental fan, assume air handler is running the full hour and can provide
     # all ventilation needs (i.e., supplemental fan does not need to run), so skip supplement fan
     vent_fans_mech = hpxml_bldg.ventilation_fans.select { |f| f.used_for_whole_building_ventilation && !f.is_cfis_supplemental_fan? && f.flow_rate > 0 && f.hours_in_operation > 0 }
     if vent_fans_mech.empty?
@@ -2635,10 +2696,10 @@ def self.get_ventilation_data(hpxml_bldg)
     q_recirc = vent_mech_shared.map { |vent_mech| vent_mech.average_total_unit_flow_rate - vent_mech.average_oa_unit_flow_rate }.sum(0.0)
 
     # Total CFMS
-    a_tot_sup = q_sup_tot + q_bal_tot + q_erv_hrv_tot + q_cfis_tot
+    q_tot_sup = q_sup_tot + q_bal_tot + q_erv_hrv_tot + q_cfis_tot
     q_tot_exh = q_exh_tot + q_bal_tot + q_erv_hrv_tot
-    q_unbal = (a_tot_sup - q_tot_exh).abs
-    q_bal = [q_tot_exh, a_tot_sup].min
+    q_unbal = q_tot_exh - q_tot_sup
+    q_bal = [q_tot_exh, q_tot_sup].min
 
     # Calculate effectiveness for all ERV/HRV and store results in a hash
     hrv_erv_effectiveness_map = Airflow.calc_hrv_erv_effectiveness(vent_mech_erv_hrv_tot)

HPXMLtoOpenStudio/tests/test_defaults.rb

@@ -1450,13 +1450,13 @@ def test_floor_furnaces
     hpxml_bldg.heating_systems[0].heating_autosizing_limit = nil
     XMLHelper.write_file(hpxml.to_doc, @tmp_hpxml_path)
     _default_hpxml, default_hpxml_bldg = _test_measure()
-    _test_default_floor_furnace_values(default_hpxml_bldg.heating_systems[0], 0, 698, nil, true, 500, 1.0)
+    _test_default_floor_furnace_values(default_hpxml_bldg.heating_systems[0], 0, nil, nil, true, 500, 1.0)
 
     # Test defaults w/o pilot
     hpxml_bldg.heating_systems[0].pilot_light = nil
     XMLHelper.write_file(hpxml.to_doc, @tmp_hpxml_path)
     _default_hpxml, default_hpxml_bldg = _test_measure()
-    _test_default_floor_furnace_values(default_hpxml_bldg.heating_systems[0], 0, 698, nil, false, nil, 1.0)
+    _test_default_floor_furnace_values(default_hpxml_bldg.heating_systems[0], 0, nil, nil, false, nil, 1.0)
   end
 
   def test_electric_resistance
@@ -1552,14 +1552,14 @@ def test_space_heaters
     hpxml_bldg.heating_systems[0].heating_capacity = 12345
     XMLHelper.write_file(hpxml.to_doc, @tmp_hpxml_path)
     _default_hpxml, default_hpxml_bldg = _test_measure()
-    _test_default_portable_heater_values(default_hpxml_bldg.heating_systems[0], 22, nil, 12345, 1.0)
+    _test_default_space_heater_values(default_hpxml_bldg.heating_systems[0], 22, nil, 12345, 1.0)
 
     # Test autosizing with factors
     hpxml_bldg.heating_systems[0].heating_capacity = nil
     hpxml_bldg.heating_systems[0].heating_autosizing_factor = 1.2
     XMLHelper.write_file(hpxml.to_doc, @tmp_hpxml_path)
     _default_hpxml, default_hpxml_bldg = _test_measure()
-    _test_default_portable_heater_values(default_hpxml_bldg.heating_systems[0], 22, nil, nil, 1.2)
+    _test_default_space_heater_values(default_hpxml_bldg.heating_systems[0], 22, nil, nil, 1.2)
 
     # Test defaults
     hpxml_bldg.heating_systems[0].fan_watts = nil
@@ -1568,7 +1568,7 @@ def test_space_heaters
     hpxml_bldg.heating_systems[0].heating_autosizing_limit = nil
     XMLHelper.write_file(hpxml.to_doc, @tmp_hpxml_path)
     _default_hpxml, default_hpxml_bldg = _test_measure()
-    _test_default_portable_heater_values(default_hpxml_bldg.heating_systems[0], 0, nil, nil, 1.0)
+    _test_default_space_heater_values(default_hpxml_bldg.heating_systems[0], 0, nil, nil, 1.0)
   end
 
   def test_fireplaces
@@ -4659,7 +4659,7 @@ def _test_default_stove_values(heating_system, fan_watts, heating_airflow_cfm, h
     end
   end
 
-  def _test_default_portable_heater_values(heating_system, fan_watts, heating_airflow_cfm, heating_capacity, heating_autosizing_factor)
+  def _test_default_space_heater_values(heating_system, fan_watts, heating_airflow_cfm, heating_capacity, heating_autosizing_factor)
     assert_equal(fan_watts, heating_system.fan_watts)
     if heating_airflow_cfm.nil? # nil implies an autosized value
       assert(heating_system.heating_airflow_cfm > 0)
@@ -4674,20 +4674,6 @@ def _test_default_portable_heater_values(heating_system, fan_watts, heating_airf
     end
   end
 
-  def _test_default_fixed_heater_values(heating_system, fan_watts, heating_airflow_cfm, heating_capacity)
-    assert_equal(fan_watts, heating_system.fan_watts)
-    if heating_airflow_cfm.nil? # nil implies an autosized value
-      assert(heating_system.heating_airflow_cfm > 0)
-    else
-      assert_equal(heating_airflow_cfm, heating_system.heating_airflow_cfm)
-    end
-    if heating_capacity.nil?
-      assert(heating_system.heating_capacity > 0)
-    else
-      assert_equal(heating_capacity, heating_system.heating_capacity)
-    end
-  end
-
   def _test_default_fireplace_values(heating_system, fan_watts, heating_airflow_cfm, heating_capacity, pilot_light, pilot_light_btuh, heating_autosizing_factor)
     assert_equal(fan_watts, heating_system.fan_watts)
     if heating_airflow_cfm.nil? # nil implies an autosized value

HPXMLtoOpenStudio/tests/test_hvac_sizing.rb

@@ -469,10 +469,12 @@ def test_manual_j_residences
     assert_in_delta(0, hpxml_bldg.hvac_plant.cdl_sens_floors, block_tol_btuh)
     assert_in_delta(0, hpxml_bldg.hvac_plant.cdl_sens_slabs, block_tol_btuh)
     assert_in_delta(865, hpxml_bldg.hvac_plant.cdl_sens_ceilings, block_tol_btuh)
-    # assert_in_delta(825, hpxml_bldg.hvac_plant.cdl_sens_infilvent, block_tol_btuh) Skip due to dehumidifying ventilation
+    assert_in_delta(0, hpxml_bldg.hvac_plant.cdl_sens_infil, block_tol_btuh)
+    assert_in_delta(825, hpxml_bldg.hvac_plant.cdl_sens_vent, block_tol_btuh)
     assert_in_delta(5541, hpxml_bldg.hvac_plant.cdl_sens_intgains, block_tol_btuh)
     assert_in_delta(655, hpxml_bldg.hvac_plant.cdl_lat_ducts, block_tol_btuh)
-    # assert_in_delta(0, hpxml_bldg.hvac_plant.cdl_lat_infilvent, block_tol_btuh) Skip due to dehumidifying ventilation
+    # assert_in_delta(0, hpxml_bldg.hvac_plant.cdl_lat_infil, block_tol_btuh) Skip due to dehumidifying ventilation
+    assert_in_delta(1938, hpxml_bldg.hvac_plant.cdl_lat_vent, block_tol_btuh)
     assert_in_delta(800, hpxml_bldg.hvac_plant.cdl_lat_intgains, block_tol_btuh)
 
     # Fixme: Skylight not included so disable for now

workflow/tests/ACCA_Examples/Walker_Residence.xml

@@ -985,9 +985,10 @@
           <VentilationFans>
             <VentilationFan>
               <SystemIdentifier id='VentilationFan1'/>
-              <FanType>supply only</FanType>
+              <FanType>central fan integrated supply</FanType>
               <RatedFlowRate>50.0</RatedFlowRate>
               <UsedForWholeBuildingVentilation>true</UsedForWholeBuildingVentilation>
+              <AttachedToHVACDistributionSystem idref='HVACDistribution1'/>
             </VentilationFan>
           </VentilationFans>
         </MechanicalVentilation>

workflow/tests/base_results/results_hers_hvac.csv

@@ -1,8 +1,8 @@
 Test Case,HVAC (kWh or therm),HVAC Fan (kWh)
 HVAC1a.xml,6277.0,803.89
 HVAC1b.xml,4660.12,803.89
-HVAC2a.xml,639.47,623.36
-HVAC2b.xml,554.21,623.36
+HVAC2a.xml,639.46,623.66
+HVAC2b.xml,554.19,623.66
 HVAC2c.xml,7623.36,1192.21
 HVAC2d.xml,4619.68,1192.21
-HVAC2e.xml,14618.09,623.36
+HVAC2e.xml,14617.8,623.66