Set source side inlet/outlet heights too.

Changelog.md

@@ -42,6 +42,7 @@ __Bugfixes__
 - Fixes utility bill calculations if there is battery storage or a generator.
 - BuildResidentialScheduleFile measure: Fixes possible divide by zero error during generation of stochastic clothes washer and dishwasher schedules.
 - Allows negative values for `Building/Site/Elevation`.
+- Fixes lower element height for a water heater using the advanced `WaterHeatingSystem/extension/TankModelType=stratified`.
 
 ## OpenStudio-HPXML v1.8.1
 

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>15c66a5f-ad2c-4455-adde-274bb424fef6</version_id>
-  <version_modified>2024-10-04T16:44:08Z</version_modified>
+  <version_id>2ecbdcc0-d0e3-4c8f-b8f8-a839e9bdbee1</version_id>
+  <version_modified>2024-10-04T17:02:56Z</version_modified>
   <xml_checksum>D8922A73</xml_checksum>
   <class_name>HPXMLtoOpenStudio</class_name>
   <display_name>HPXML to OpenStudio Translator</display_name>
@@ -627,7 +627,7 @@
       <filename>waterheater.rb</filename>
       <filetype>rb</filetype>
       <usage_type>resource</usage_type>
-      <checksum>949A7458</checksum>
+      <checksum>1E7D40B1</checksum>
     </file>
     <file>
       <filename>weather.rb</filename>

HPXMLtoOpenStudio/resources/waterheater.rb

@@ -911,7 +911,7 @@ def self.setup_hpwh_wrapped_condenser(model, obj_name, coil, tank, fan, airflow_
     hpwh = OpenStudio::Model::WaterHeaterHeatPumpWrappedCondenser.new(model, coil, tank, fan, setpoint_schedule, model.alwaysOnDiscreteSchedule)
     hpwh.setName("#{obj_name} hpwh")
     hpwh.setDeadBandTemperatureDifference(3.89)
-    hpwh.setCondenserBottomLocation(0.01) # bottom node
+    hpwh.setCondenserBottomLocation((1.0 - (12 - 0.5) / 12.0) * tank.tankHeight.get) # in the 12th node of a 12-node tank (counting from top)
     hpwh.setCondenserTopLocation((1.0 - (6 - 0.5) / 12.0) * tank.tankHeight.get) # in the 6th node of a 12-node tank (counting from top)
     hpwh.setEvaporatorAirFlowRate(UnitConversions.convert(airflow_rate * unit_multiplier, 'ft^3/min', 'm^3/s'))
     hpwh.setInletAirConfiguration('Schedule')
@@ -2000,8 +2000,8 @@ def self.create_new_heater(name:, water_heating_system: nil, act_vol:, t_set_c:
       new_heater.setUseSideDesignFlowRate(UnitConversions.convert(act_vol, 'gal', 'm^3') / 60.1)
       new_heater.setSourceSideDesignFlowRate(0)
       new_heater.setSourceSideFlowControlMode('')
-      new_heater.setSourceSideInletHeight(0)
-      new_heater.setSourceSideOutletHeight(0)
+      new_heater.setSourceSideInletHeight((1.0 - (1 - 0.5) / 15) * h_tank) # in the 1st node of a 15-node tank (counting from top)
+      new_heater.setSourceSideOutletHeight((1.0 - (15 - 0.5) / 15) * h_tank) # in the 15th node of a 15-node tank (counting from top)
       new_heater.setSkinLossFractiontoZone(1.0 / unit_multiplier) # Tank losses are multiplied by E+ zone multiplier, so need to compensate here
       new_heater.setOffCycleFlueLossFractiontoZone(1.0 / unit_multiplier)
       set_stratified_tank_ua(new_heater, u, unit_multiplier)