Water-to-water (hydronic) geothermal heat pumps

[joseph-robertson]

Pull Request Description

Support modeling ground-to-water heat pumps.

I'm currently testing a four-pipe configuration (fan coil) using /c/openstudio-3.10.0/bin/openstudio.exe workflow/run_simulation.rb -x workflow/sample_files/base-hvac-ground-to-water-heat-pump.xml.

Checklist

• ElectricAuxiliaryEnergy. Should ground-to-water have this optional field (similar to boiler)? My feeling is No, unless we have a default value.
• SharedLoopWatts or FanCoilWatts. Should either of these fields have default values? Currently the former is required (if shared system) and the latter is defaulted to 150W.
• Fan coil energy. Is it correct to account for this by including FanCoilWatts in the pump power calculation (similar to boiler)?
• DSE. Should this be supported? It isn't for Boiler (Shared), but is for Boiler (In-Unit) and Ground-to-Air Heat Pump.
• Source / load side flow rates. Source side should be the geothermal loop flow rate? Or do we need a higher flow rate?
• Curves (cap, eir, plr). Using what ComStock has already derived would not be appropriate?
• Reference cop. Using what ComStock has already derived would not be appropriate?
• Supply temperatures. 140F for heating and 44F for cooling?
• HVAC sizing. Currently just borrowing code from ground-to-air.
• HVAC installation quality. Support this? Replace airflow defect with water flow defect, or somehow support charge defect without airflow defect?
• Supplemental heating coil. Would integrated backup be supported?
• Like Boiler (Shared), should we support duct losses? I.e., fan coil in a mechanical room that provides heating/cooling to conditioned space.
• How realistic are "a couple fan coils placed throughout" a house? Are these something like the hotel units, but placed in various locations in your house? Double-check w/Jon.
• Buffer tank (like AWHP uses)? Haven't seen this.

Checklist

Not all may apply:

• Schematron validator (EPvalidator.sch) has been updated
• Sample files have been added/updated (openstudio tasks.rb update_hpxmls)
• Tests have been added/updated (e.g., HPXMLtoOpenStudio/tests/test*.rb and/or workflow/tests/test*.rb)
• Documentation has been updated
• Changelog has been updated
• openstudio tasks.rb update_measures has been run
• No unexpected changes to simulation results of sample files

[shorowit]

#736