NatLabRockies · yzhou601 · Apr 30, 2026 · Apr 30, 2026 · Apr 30, 2026 · Apr 30, 2026
diff --git a/Changelog.md b/Changelog.md
@@ -48,6 +48,7 @@ __Bugfixes__
 - Fixes PV grid connection fee applying in utility bill calculation even if the home has no PV.
 - Fixes possible "Failed to process String" EnergyPlus error when requesting component loads.
 - Fixes ducts in manufactured home belly from being incorrectly modeled as if they were outside.
+- Fixes ground-source heat pump experimental model using wrong rated condition inputs.
 
 ## OpenStudio-HPXML v1.11.1
 

diff --git a/HPXMLtoOpenStudio/measure.xml b/HPXMLtoOpenStudio/measure.xml
@@ -3,8 +3,8 @@
   <schema_version>3.1</schema_version>
   <name>hpxml_to_openstudio</name>
   <uid>b1543b30-9465-45ff-ba04-1d1f85e763bc</uid>
-  <version_id>c6afec99-c1c2-4e83-9bee-102d983c0cb1</version_id>
-  <version_modified>2026-05-22T21:28:36Z</version_modified>
+  <version_id>94711da9-1580-4b00-99c6-473b2dcf2af2</version_id>
+  <version_modified>2026-06-01T22:06:14Z</version_modified>
   <xml_checksum>D8922A73</xml_checksum>
   <class_name>HPXMLToOpenStudio</class_name>
   <display_name>HPXML to OpenStudio Translator</display_name>
@@ -367,7 +367,7 @@
       <filename>defaults.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>A3B194F3</checksum>
+      <checksum>3FAD0E6C</checksum>
     </file>
     <file>
       <filename>electric_panel.rb</filename>
@@ -433,13 +433,13 @@
       <filename>hvac.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>DF5A0B42</checksum>
+      <checksum>6DCDB9F0</checksum>
     </file>
     <file>
       <filename>hvac_sizing.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>A450945A</checksum>
+      <checksum>CC053A51</checksum>
     </file>
     <file>
       <filename>internal_gains.rb</filename>
@@ -781,7 +781,7 @@
       <filename>test_hvac.rb</filename>
       <filetype>rb</filetype>
       <usage_type>test</usage_type>
-      <checksum>8D9CC019</checksum>
+      <checksum>840B2D62</checksum>
     </file>
     <file>
       <filename>test_hvac_sizing.rb</filename>

diff --git a/HPXMLtoOpenStudio/resources/defaults.rb b/HPXMLtoOpenStudio/resources/defaults.rb
@@ -7942,13 +7942,13 @@ def self.interpolate_seer2(seer2, eer2, seer2_array, seer2_eer2_ratio_array, cop
           # Cooling Curves
           # E+ Capacity and EIR as function of temperature curves(bi-quadratic) generated using E+ HVACCurveFitTool
           # See: https://bigladdersoftware.com/epx/docs/24-2/auxiliary-programs/hvac-performance-curve-fit-tool.html#hvac-performance-curve-fit-tool
-          # Catalog data from : https://files.climatemaster.com/Genesis-GS-Series-Product-Catalog.pdf, p180
+          # Catalog data from : https://www.climatemaster.com/download/18.274be999165850ccd5b5b73/1535543867815/lc377-climatemaster-commercial-tranquility-20-single-stage-ts-series-water-source-heat-pump-submittal-set.pdf
           # Using E+ rated conditions:
           # Cooling: Indoor air at 67F WB, 80F DB; Entering water temperature: 85F
           clg_ap.cool_cap_ft_spec = [[0.3926140238, 0.0297981297, 0.0000000582, 0.0123906803, -0.0003014284, -0.0001113698]]
           clg_ap.cool_eir_ft_spec = [[1.1828664909, -0.0450835550, 0.0009273315, 0.0056194113, 0.0006683467, -0.0007256237]]
           clg_ap.cool_cap_fflow_spec = [[0.5068, 0.8099, -0.3165]]
-          clg_ap.cool_eir_fflow_spec = [[2.0184, -1.6182, 0.5789]]
+          clg_ap.cool_eir_fflow_spec = [[1.4249, -0.8767, 0.4518]]
           clg_ap.cool_cap_fwf_spec = [[1.0, 0.0, 0.0]]
           clg_ap.cool_eir_fwf_spec = [[1.0, 0.0, 0.0]]
           cool_cop_ratios = [1.0]
@@ -7973,7 +7973,7 @@ def self.interpolate_seer2(seer2, eer2, seer2_array, seer2_eer2_ratio_array, cop
           clg_ap.cool_eir_fwf_spec = [[1.7131, -1.3055, 0.5924],
                                       [1.5872, -1.055, 0.4678]]
 
-          # Catalog data from ClimateMaster residential tranquility 30 premier two-stage series Model SE036: https://files.climatemaster.com/RP3001-Residential-SE-Product-Catalog.pdf
+          # Rated data from ClimateMaster residential tranquility 30 premier two-stage series Model SE036: https://files.climatemaster.com/RP3001-Residential-SE-Product-Catalog.pdf
           cool_cop_ratios = [1.102827763, 1.0]
         when HPXML::HVACCompressorTypeVariableSpeed
           clg_ap.cool_capacity_ratios = [0.4802, 1.0]
@@ -8144,13 +8144,13 @@ def self.interpolate_hspf2(hspf2, qm17full, hspf2_array, qm17full_array, cop47fu
           # Heating Curves
           # E+ Capacity and EIR as function of temperature curves(bi-quadratic) generated using E+ HVACCurveFitTool
           # See: https://bigladdersoftware.com/epx/docs/24-2/auxiliary-programs/hvac-performance-curve-fit-tool.html#hvac-performance-curve-fit-tool
-          # Catalog data from : https://files.climatemaster.com/Genesis-GS-Series-Product-Catalog.pdf, p180
+          # Catalog data from : https://www.climatemaster.com/download/18.274be999165850ccd5b5b73/1535543867815/lc377-climatemaster-commercial-tranquility-20-single-stage-ts-series-water-source-heat-pump-submittal-set.pdf
           # Using E+ rated conditions:
           # Heating: Indoor air at 70F DB; Entering water temperature: 70F
           htg_ap.heat_cap_ft_spec = [[0.7353127278, -0.0035056759, -0.0000439615, 0.0204411095, -0.0000320781, -0.0001322685]]
           htg_ap.heat_eir_ft_spec = [[0.6273820540, 0.0124891750, 0.0012720188, -0.0151581268, 0.0004164343, -0.0007259611]]
           htg_ap.heat_cap_fflow_spec = [[0.7594, 0.3642, -0.1234]]
-          htg_ap.heat_eir_fflow_spec = [[2.796, -3.0886, 1.3858]]
+          htg_ap.heat_eir_fflow_spec = [[2.3403, -2.3479, 1.0068]]
           htg_ap.heat_cap_fwf_spec = [[1.0, 0.0, 0.0]]
           htg_ap.heat_eir_fwf_spec = [[1.0, 0.0, 0.0]]
           heat_cop_ratios = [1.0]
@@ -8174,7 +8174,7 @@ def self.interpolate_hspf2(hspf2, qm17full, hspf2_array, qm17full_array, cop47fu
                                       [0.769, 0.399, -0.168]]
           htg_ap.heat_eir_fwf_spec = [[1.3457, -0.6658, 0.3201],
                                       [1.1679, -0.3215, 0.1535]]
-          # Catalog data from ClimateMaster residential tranquility 30 premier two-stage series Model SE036: https://files.climatemaster.com/RP3001-Residential-SE-Product-Catalog.pdf
+          # Rated data from ClimateMaster residential tranquility 30 premier two-stage series Model SE036: https://files.climatemaster.com/RP3001-Residential-SE-Product-Catalog.pdf
           heat_cop_ratios = [1.161791639, 1.0]
         when HPXML::HVACCompressorTypeVariableSpeed
           htg_ap.heat_capacity_ratios = [0.4473, 1.0]

diff --git a/HPXMLtoOpenStudio/resources/hvac.rb b/HPXMLtoOpenStudio/resources/hvac.rb
@@ -13,11 +13,11 @@ module HVAC
   ActualCFMPerTonHeat = 240.0 # cfm/ton of rated capacity, default actual airflow rate for furnaces, RESNET
   MinCapacity = 1.0 # Btuh
   MinAirflow = 3.0 # cfm; E+ min airflow is 0.001 m3/s
-  GroundSourceHeatRatedWET = 70.0 # degF, Rated water entering temperature for ground-source systems, heating
   GroundSourceHeatRatedIDB = 70.0 # degF, Rated indoor drybulb for ground-source systems, heating
-  GroundSourceCoolRatedWET = 85.0 # degF, Rated water entering temperature for ground-source systems, cooling
   GroundSourceCoolRatedIDB = 80.0 # degF, Rated indoor drybulb for ground-source systems, cooling
   GroundSourceCoolRatedIWB = 67.0 # degF, Rated indoor wetbulb for ground-source systems, cooling
+  GroundSourceHeatGLHPRatedEWT = 32.0 # degF, Rated water entering temperature for ground-source systems, heating
+  GroundSourceCoolGLHPRatedEWT = 77.0 # degF, Rated water entering temperature for ground-source systems, cooling
 
   # Adds any HVAC Systems to the OpenStudio model.
   #
@@ -670,6 +670,8 @@ def self.apply_ground_source_heat_pump(runner, model, weather, hpxml_bldg, hpxml
           min_x: 0, max_x: 1, min_y: 0.7, max_y: 1
         )
       end
+      # convert GLHP rated capacities to E+ rated
+      clg_capacity_rated_eplus = UnitConversions.convert(heat_pump.cooling_capacity, 'Btu/hr', 'W') / get_experimental_ghp_rated_condition_conversion(:clg, hp_ap.cool_cap_ft_spec[-1])
       clg_coil = OpenStudio::Model::CoilCoolingWaterToAirHeatPumpVariableSpeedEquationFit.new(model, plf_fplr_curve)
       clg_coil.setName(obj_name + ' clg coil')
       clg_coil.setNominalTimeforCondensatetoBeginLeavingtheCoil(1000)
@@ -678,7 +680,7 @@ def self.apply_ground_source_heat_pump(runner, model, weather, hpxml_bldg, hpxml
       clg_coil.setRatedAirFlowRateAtSelectedNominalSpeedLevel(clg_air_flow_rated)
       clg_coil.setRatedWaterFlowRateAtSelectedNominalSpeedLevel(UnitConversions.convert(geothermal_loop.loop_flow, 'gal/min', 'm^3/s'))
       # TODO: Add net to gross conversion after RESNET PR: https://github.com/NatLabRockies/OpenStudio-HPXML/pull/1879
-      clg_coil.setGrossRatedTotalCoolingCapacityAtSelectedNominalSpeedLevel(UnitConversions.convert(heat_pump.cooling_capacity, 'Btu/hr', 'W'))
+      clg_coil.setGrossRatedTotalCoolingCapacityAtSelectedNominalSpeedLevel(clg_capacity_rated_eplus)
       for i in 0..(num_speeds - 1)
         cap_ft_curve = Model.add_curve_biquadratic(
           model,
@@ -723,10 +725,12 @@ def self.apply_ground_source_heat_pump(runner, model, weather, hpxml_bldg, hpxml
           coeff: [1, 0, 0, 0, 0, 0]
         )
         speed = OpenStudio::Model::CoilCoolingWaterToAirHeatPumpVariableSpeedEquationFitSpeedData.new(model, cap_ft_curve, cap_faf_curve, cap_fwf_curve, eir_ft_curve, eir_faf_curve, eir_fwf_curve, waste_heat_ft)
+        # convert GLHP rated COPs to E+ rated
+        rated_cop_eplus = hp_ap.cool_rated_cops[i] * get_experimental_ghp_rated_condition_conversion(:clg, hp_ap.cool_eir_ft_spec[i])
         # TODO: Add net to gross conversion after RESNET PR: https://github.com/NatLabRockies/OpenStudio-HPXML/pull/1879
-        speed.setReferenceUnitGrossRatedTotalCoolingCapacity(UnitConversions.convert(heat_pump.cooling_capacity, 'Btu/hr', 'W') * hp_ap.cool_capacity_ratios[i])
+        speed.setReferenceUnitGrossRatedTotalCoolingCapacity(clg_capacity_rated_eplus * hp_ap.cool_capacity_ratios[i])
         speed.setReferenceUnitGrossRatedSensibleHeatRatio(hp_ap.cool_rated_shr_gross)
-        speed.setReferenceUnitGrossRatedCoolingCOP(hp_ap.cool_rated_cops[i])
+        speed.setReferenceUnitGrossRatedCoolingCOP(rated_cop_eplus)
         speed.setReferenceUnitRatedAirFlowRate(UnitConversions.convert(UnitConversions.convert(heat_pump.cooling_capacity, 'Btu/hr', 'ton') * hp_ap.cool_capacity_ratios[i] * hp_ap.cool_rated_cfm_per_ton, 'cfm', 'm^3/s'))
         speed.setReferenceUnitRatedWaterFlowRate(UnitConversions.convert(geothermal_loop.loop_flow, 'gal/min', 'm^3/s') * hp_ap.cool_capacity_ratios[i])
         speed.setReferenceUnitWasteHeatFractionofInputPowerAtRatedConditions(0.0)
@@ -751,10 +755,12 @@ def self.apply_ground_source_heat_pump(runner, model, weather, hpxml_bldg, hpxml
       htg_coil = OpenStudio::Model::CoilHeatingWaterToAirHeatPumpVariableSpeedEquationFit.new(model, plf_fplr_curve)
       htg_coil.setName(obj_name + ' htg coil')
       htg_coil.setNominalSpeedLevel(num_speeds)
+      # convert GLHP rated capacities to E+ rated
+      htg_capacity_rated_eplus = UnitConversions.convert(heat_pump.heating_capacity, 'Btu/hr', 'W') / get_experimental_ghp_rated_condition_conversion(:htg, hp_ap.heat_cap_ft_spec[-1])
       htg_coil.setRatedAirFlowRateAtSelectedNominalSpeedLevel(htg_air_flow_rated)
       htg_coil.setRatedWaterFlowRateAtSelectedNominalSpeedLevel(UnitConversions.convert(geothermal_loop.loop_flow, 'gal/min', 'm^3/s'))
       # TODO: Add net to gross conversion after RESNET PR: https://github.com/NatLabRockies/OpenStudio-HPXML/pull/1879
-      htg_coil.setRatedHeatingCapacityAtSelectedNominalSpeedLevel(UnitConversions.convert(heat_pump.heating_capacity, 'Btu/hr', 'W'))
+      htg_coil.setRatedHeatingCapacityAtSelectedNominalSpeedLevel(htg_capacity_rated_eplus)
       for i in 0..(num_speeds - 1)
         cap_ft_curve = Model.add_curve_biquadratic(
           model,
@@ -799,9 +805,11 @@ def self.apply_ground_source_heat_pump(runner, model, weather, hpxml_bldg, hpxml
           coeff: [1, 0, 0, 0, 0, 0]
         )
         speed = OpenStudio::Model::CoilHeatingWaterToAirHeatPumpVariableSpeedEquationFitSpeedData.new(model, cap_ft_curve, cap_faf_curve, cap_fwf_curve, eir_ft_curve, eir_faf_curve, eir_fwf_curve, waste_heat_ft)
+        # convert GLHP rated COPs to E+ rated
+        rated_cop_eplus = hp_ap.heat_rated_cops[i] * get_experimental_ghp_rated_condition_conversion(:htg, hp_ap.heat_eir_ft_spec[i])
         # TODO: Add net to gross conversion after RESNET PR: https://github.com/NatLabRockies/OpenStudio-HPXML/pull/1879
-        speed.setReferenceUnitGrossRatedHeatingCapacity(UnitConversions.convert(heat_pump.heating_capacity, 'Btu/hr', 'W') * hp_ap.heat_capacity_ratios[i])
-        speed.setReferenceUnitGrossRatedHeatingCOP(hp_ap.heat_rated_cops[i])
+        speed.setReferenceUnitGrossRatedHeatingCapacity(htg_capacity_rated_eplus * hp_ap.heat_capacity_ratios[i])
+        speed.setReferenceUnitGrossRatedHeatingCOP(rated_cop_eplus)
         speed.setReferenceUnitRatedAirFlow(UnitConversions.convert(UnitConversions.convert(heat_pump.heating_capacity, 'Btu/hr', 'ton') * hp_ap.heat_capacity_ratios[i] * hp_ap.heat_rated_cfm_per_ton, 'cfm', 'm^3/s'))
         speed.setReferenceUnitRatedWaterFlowRate(UnitConversions.convert(geothermal_loop.loop_flow, 'gal/min', 'm^3/s') * hp_ap.heat_capacity_ratios[i])
         speed.setReferenceUnitWasteHeatFractionofInputPowerAtRatedConditions(0.0)
@@ -845,6 +853,26 @@ def self.apply_ground_source_heat_pump(runner, model, weather, hpxml_bldg, hpxml
     return air_loop
   end
 
+  # Get the curve value at GLHP rated conditions (Only used for experimental model because E+ rated conditions are different from GLHP rated conditions)
+  #
+  # @param mode [Symbol] Heating or cooling
+  # @param biquadratic_spec [Array<Double>] EIR or Capacity function of temperature biquadratic curve coefficients
+  # @return [Double] Curve value at GLHP rated conditions for conversion
+  def self.get_experimental_ghp_rated_condition_conversion(mode, biquadratic_spec)
+    case mode
+    when :clg
+      return MathTools.biquadratic(UnitConversions.convert(GroundSourceCoolRatedIWB, 'F', 'C'),
+                                   UnitConversions.convert(GroundSourceCoolGLHPRatedEWT, 'F', 'C'),
+                                   biquadratic_spec)
+    when :htg
+      return MathTools.biquadratic(UnitConversions.convert(GroundSourceHeatRatedIDB, 'F', 'C'),
+                                   UnitConversions.convert(GroundSourceHeatGLHPRatedEWT, 'F', 'C'),
+                                   biquadratic_spec)
+    else
+      fail "Unexpected mode: #{mode}."
+    end
+  end
+
   # Adds the HPXML GeothermalLoop to the OpenStudio model. If it has already been
   # added to the model (because there are multiple ground-source heat pumps attached
   # to it), then it reuses the existing one.

diff --git a/HPXMLtoOpenStudio/resources/hvac_sizing.rb b/HPXMLtoOpenStudio/resources/hvac_sizing.rb
@@ -2841,7 +2841,10 @@ def self.apply_hvac_equipment_adjustments(mj, runner, hvac_sizings, weather, hva
         hvac_sizings.Cool_Capacity_Sens = hvac_sizings.Cool_Capacity * clg_ap.cool_rated_shr_gross
         hvac_sizings.Cool_Airflow = calc_airflow_rate(:clg, hvac_cooling, hvac_sizings.Cool_Capacity, hpxml_bldg)
       elsif [HPXML::GroundToAirHeatPumpModelTypeExperimental].include? hpxml_header.ground_to_air_heat_pump_model_type
-        total_cap_curve_value = MathTools.biquadratic(UnitConversions.convert(mj.cool_indoor_wetbulb, 'F', 'C'), UnitConversions.convert(entering_temp, 'F', 'C'), clg_ap.cool_cap_ft_spec[hvac_cooling_speed])
+        # Need to adjust the capacity to GLHP rated conditions
+        total_cap_curve_value_design = MathTools.biquadratic(UnitConversions.convert(mj.cool_indoor_wetbulb, 'F', 'C'), UnitConversions.convert(entering_temp, 'F', 'C'), clg_ap.cool_cap_ft_spec[hvac_cooling_speed])
+        total_cap_curve_value_glhp_rated = HVAC.get_experimental_ghp_rated_condition_conversion(:clg, clg_ap.cool_cap_ft_spec[hvac_cooling_speed])
+        total_cap_curve_value = total_cap_curve_value_design / total_cap_curve_value_glhp_rated
         calculate_cooling_capacities(mj, clg_ap, hvac_sizings, hpxml_bldg.header.manualj_humidity_setpoint, total_cap_curve_value, undersize_limit, oversize_limit, HVAC::GroundSourceCoolRatedIDB, HVAC::GroundSourceCoolRatedIWB, hvac_cooling, hpxml_bldg)
       end
     elsif HPXML::HVACTypeEvaporativeCooler == cooling_type
@@ -3922,7 +3925,9 @@ def self.calc_gshp_htg_curve_value(htg_ap, hpxml_header, db_temp, w_temp, hvac_h
 
       htg_cap_curve_value = MathTools.quadlinear(db_temp / ref_temp, w_temp / ref_temp, 1.0, 1.0, htg_ap.heat_cap_curve_spec[hvac_heating_speed])
     elsif (hpxml_header.ground_to_air_heat_pump_model_type == HPXML::GroundToAirHeatPumpModelTypeExperimental)
-      htg_cap_curve_value = MathTools.biquadratic(UnitConversions.convert(db_temp, 'F', 'C'), UnitConversions.convert(w_temp, 'F', 'C'), htg_ap.heat_cap_ft_spec[hvac_heating_speed])
+      htg_cap_curve_value_design = MathTools.biquadratic(UnitConversions.convert(db_temp, 'F', 'C'), UnitConversions.convert(w_temp, 'F', 'C'), htg_ap.heat_cap_ft_spec[hvac_heating_speed])
+      htg_cap_curve_value_glhp_rated = HVAC.get_experimental_ghp_rated_condition_conversion(:htg, htg_ap.heat_cap_ft_spec[hvac_heating_speed])
+      htg_cap_curve_value = htg_cap_curve_value_design / htg_cap_curve_value_glhp_rated
     end
 
     return htg_cap_curve_value