Merge pull request #1527 from NREL/1_and_2_speed_hvac_regressions

Replace HVAC inverse calculations with regressions

Author: shorowit

Changelog.md

@@ -16,9 +16,10 @@ __New Features__
   - Allows `NumberofUnits` to be used as a multiplier on dwelling unit simulation results to reduce simulation runtime.
   - See the [OpenStudio-HPXML documentation](https://openstudio-hpxml.readthedocs.io/en/v1.7.0/workflow_inputs.html#whole-sfa-mf-buildings) for more detail.
 - HVAC modeling updates:
-  - Updated assumptions for variable-speed air conditioners, heat pumps, and mini-splits.
+  - Updated assumptions for variable-speed air conditioners, heat pumps, and mini-splits based on NEEP data. Expect results to change, potentially significantly so depending on the scenario.
   - Allows detailed heating and cooling performance data (min/max COPs and capacities at different outdoor temperatures) for variable-speed systems.
   - Updates deep ground temperatures (used for modeling ground-source heat pumps) using L. Xing's simplified design model (2014).
+  - Replaces inverse calculations, used to calculate COPs from rated efficiencies, with regressions for single/two-speed central ACs and ASHPs.
 - Output updates:
   - **Breaking change**: "Hot Tub" outputs renamed to "Permanent Spa".
   - Adds "Peak Electricity: Annual Total (W)" output.
@@ -50,6 +51,7 @@ __Bugfixes__
 - Fixes missing radiation exchange between window and sky when an interior/exterior window shading multiplier less than 1 exists.
 - Fixes monthly shallow ground temperatures (used primarily in HVAC autosizing) for the southern hemisphere.
 - Various HVAC sizing bugfixes and improvements.
+- Fixes low-speed heating COPs for some two-speed ASHPs and cooling COPs for some single-speed ACs/HPs.
 - BuildResidentialHPXML measure: Fixes air distribution CFA served when there is not a central system that meets 100% of the load.
 
 ## OpenStudio-HPXML v1.6.0

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>cfae944b-c977-42d1-915c-b9231c3a3fdd</version_id>
-  <version_modified>2023-11-13T20:11:06Z</version_modified>
+  <version_id>441f9a3f-8b7f-4b51-87b8-fc22b13ec262</version_id>
+  <version_modified>2023-11-13T22:10:19Z</version_modified>
   <xml_checksum>D8922A73</xml_checksum>
   <class_name>HPXMLtoOpenStudio</class_name>
   <display_name>HPXML to OpenStudio Translator</display_name>
@@ -292,13 +292,13 @@
       <filename>hvac.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>B601226F</checksum>
+      <checksum>B014F262</checksum>
     </file>
     <file>
       <filename>hvac_sizing.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>6458264A</checksum>
+      <checksum>00BE0F0C</checksum>
     </file>
     <file>
       <filename>lighting.rb</filename>
@@ -568,7 +568,7 @@
       <filename>test_hvac.rb</filename>
       <filetype>rb</filetype>
       <usage_type>test</usage_type>
-      <checksum>93FAD19F</checksum>
+      <checksum>19EE9DA5</checksum>
     </file>
     <file>
       <filename>test_hvac_sizing.rb</filename>

HPXMLtoOpenStudio/resources/hvac.rb

@@ -2755,8 +2755,8 @@ def self.gshp_hxbore_ft_per_ton(weather, hvac_cooling_ap, bore_spacing, pipe_r_v
     rtf_DesignMon_Heat = [0.25, (71.0 - weather.data.MonthlyAvgDrybulbs[heating_month]) / @htd].max
     rtf_DesignMon_Cool = [0.25, (weather.data.MonthlyAvgDrybulbs[cooling_month] - 76.0) / @ctd].max
 
-    nom_length_heat = (1.0 - hvac_cooling_ap.heat_rated_eirs[0]) * (r_value_bore + r_value_ground * rtf_DesignMon_Heat) / (weather.data.DeepGroundAnnualTemp - (2.0 * hvac_cooling_ap.design_hw - hvac_cooling_ap.design_delta_t) / 2.0) * UnitConversions.convert(1.0, 'ton', 'Btu/hr')
-    nom_length_cool = (1.0 + hvac_cooling_ap.cool_rated_eirs[0]) * (r_value_bore + r_value_ground * rtf_DesignMon_Cool) / ((2.0 * hvac_cooling_ap.design_chw + hvac_cooling_ap.design_delta_t) / 2.0 - weather.data.DeepGroundAnnualTemp) * UnitConversions.convert(1.0, 'ton', 'Btu/hr')
+    nom_length_heat = (1.0 - 1.0 / hvac_cooling_ap.heat_rated_cops[0]) * (r_value_bore + r_value_ground * rtf_DesignMon_Heat) / (weather.data.DeepGroundAnnualTemp - (2.0 * hvac_cooling_ap.design_hw - hvac_cooling_ap.design_delta_t) / 2.0) * UnitConversions.convert(1.0, 'ton', 'Btu/hr')
+    nom_length_cool = (1.0 + 1.0 / hvac_cooling_ap.cool_rated_cops[0]) * (r_value_bore + r_value_ground * rtf_DesignMon_Cool) / ((2.0 * hvac_cooling_ap.design_chw + hvac_cooling_ap.design_delta_t) / 2.0 - weather.data.DeepGroundAnnualTemp) * UnitConversions.convert(1.0, 'ton', 'Btu/hr')
 
     return nom_length_heat, nom_length_cool
   end

HPXMLtoOpenStudio/resources/hvac_sizing.rb

@@ -29,7 +29,7 @@ def test_central_air_conditioner_1_speed
       # Check cooling coil
       assert_equal(1, model.getCoilCoolingDXSingleSpeeds.size)
       clg_coil = model.getCoilCoolingDXSingleSpeeds[0]
-      assert_in_epsilon(3.73, clg_coil.ratedCOP, 0.01)
+      assert_in_epsilon(3.77, clg_coil.ratedCOP, 0.01)
       assert_in_epsilon(7230, clg_coil.ratedTotalCoolingCapacity.get, 0.01)
 
       # Check EMS
@@ -49,7 +49,7 @@ def test_central_air_conditioner_2_speed
     assert_equal(1, model.getCoilCoolingDXMultiSpeeds.size)
     clg_coil = model.getCoilCoolingDXMultiSpeeds[0]
     assert_equal(2, clg_coil.stages.size)
-    [4.95, 4.59].each_with_index do |cop, i|
+    [4.95, 4.53].each_with_index do |cop, i|
       assert_in_epsilon(cop, clg_coil.stages[i].grossRatedCoolingCOP, 0.01)
     end
     [5143, 7158].each_with_index do |capacity, i|
@@ -449,13 +449,13 @@ def test_air_to_air_heat_pump_1_speed
       # Check cooling coil
       assert_equal(1, model.getCoilCoolingDXSingleSpeeds.size)
       clg_coil = model.getCoilCoolingDXSingleSpeeds[0]
-      assert_in_epsilon(3.73, clg_coil.ratedCOP, 0.01)
+      assert_in_epsilon(3.77, clg_coil.ratedCOP, 0.01)
       assert_in_epsilon(10846, clg_coil.ratedTotalCoolingCapacity.get, 0.01)
 
       # Check heating coil
       assert_equal(1, model.getCoilHeatingDXSingleSpeeds.size)
       htg_coil = model.getCoilHeatingDXSingleSpeeds[0]
-      assert_in_epsilon(3.28, htg_coil.ratedCOP, 0.01)
+      assert_in_epsilon(3.29, htg_coil.ratedCOP, 0.01)
       assert_in_epsilon(10262, htg_coil.ratedTotalHeatingCapacity.get, 0.01)
 
       # Check supp heating coil
@@ -527,7 +527,7 @@ def test_air_to_air_heat_pump_2_speed
     assert_equal(1, model.getCoilCoolingDXMultiSpeeds.size)
     clg_coil = model.getCoilCoolingDXMultiSpeeds[0]
     assert_equal(2, clg_coil.stages.size)
-    [4.95, 4.59].each_with_index do |cop, i|
+    [4.95, 4.53].each_with_index do |cop, i|
       assert_in_epsilon(cop, clg_coil.stages[i].grossRatedCoolingCOP, 0.01)
     end
     [7715, 10736].each_with_index do |clg_capacity, i|
@@ -538,7 +538,7 @@ def test_air_to_air_heat_pump_2_speed
     assert_equal(1, model.getCoilHeatingDXMultiSpeeds.size)
     htg_coil = model.getCoilHeatingDXMultiSpeeds[0]
     assert_equal(2, htg_coil.stages.size)
-    [4.52, 4.08].each_with_index do |cop, i|
+    [4.52, 3.93].each_with_index do |cop, i|
       assert_in_epsilon(cop, htg_coil.stages[i].grossRatedHeatingCOP, 0.01)
     end
     [7499, 10360].each_with_index do |htg_capacity, i|
@@ -810,7 +810,7 @@ def test_shared_chiller_baseboard
     # Check cooling coil
     assert_equal(1, model.getCoilCoolingDXSingleSpeeds.size)
     clg_coil = model.getCoilCoolingDXSingleSpeeds[0]
-    assert_in_epsilon(3.85, clg_coil.ratedCOP, 0.01)
+    assert_in_epsilon(3.62, clg_coil.ratedCOP, 0.01)
     refute_in_epsilon(capacity, clg_coil.ratedTotalCoolingCapacity.get, 0.01) # Uses autosized capacity
   end
 
@@ -826,7 +826,7 @@ def test_shared_chiller_fan_coil
     # Check cooling coil
     assert_equal(1, model.getCoilCoolingDXSingleSpeeds.size)
     clg_coil = model.getCoilCoolingDXSingleSpeeds[0]
-    assert_in_epsilon(3.45, clg_coil.ratedCOP, 0.01)
+    assert_in_epsilon(3.31, clg_coil.ratedCOP, 0.01)
     refute_in_epsilon(capacity, clg_coil.ratedTotalCoolingCapacity.get, 0.01) # Uses autosized capacity
   end
 
@@ -842,7 +842,7 @@ def test_shared_chiller_water_loop_heat_pump
     # Check cooling coil
     assert_equal(1, model.getCoilCoolingDXSingleSpeeds.size)
     clg_coil = model.getCoilCoolingDXSingleSpeeds[0]
-    assert_in_epsilon(1.30, clg_coil.ratedCOP, 0.01)
+    assert_in_epsilon(1.50, clg_coil.ratedCOP, 0.01)
     refute_in_epsilon(capacity, clg_coil.ratedTotalCoolingCapacity.get, 0.01) # Uses autosized capacity
   end
 
@@ -858,7 +858,7 @@ def test_shared_cooling_tower_water_loop_heat_pump
     # Check cooling coil
     assert_equal(1, model.getCoilCoolingDXSingleSpeeds.size)
     clg_coil = model.getCoilCoolingDXSingleSpeeds[0]
-    assert_in_epsilon(3.68, clg_coil.ratedCOP, 0.01)
+    assert_in_epsilon(3.50, clg_coil.ratedCOP, 0.01)
     refute_in_epsilon(capacity, clg_coil.ratedTotalCoolingCapacity.get, 0.01) # Uses autosized capacity
   end