AirLoopHVACUnitarySystem: Supply Air Flow Rate Method During <XXX> Operation should be set via related setters/autosize

[jmarrec]

Issue overview

Supply Air Flow Rate Method During <XXX> Operation should be automatically infered at model time.

Current Behavior

Supply Air Flow Rate Method During <XXX> Operation isn't set by default. E+ shows a warning in the eplusout.err

   ** Warning ** AirLoopHVAC:UnitarySystem = AIR LOOP HVAC UNITARY SYSTEM 1
   **   ~~~   ** Method used to determine the cooling supply air flow rate is not specified when cooling coil is present.
   ** Warning ** AirLoopHVAC:UnitarySystem = AIR LOOP HVAC UNITARY SYSTEM 1
   **   ~~~   ** Method used to determine the heating supply air flow rate is not specified when heating coil is present.

Expected Behavior

eg setSupplyAirFlowRatePerFloorAreaDuringCoolingOperation(1.0)should set the Supply Air Flow Rate Method During Cooling Operation to FlowPerFloorArea

autosizeSupplyAirFlowRateDuringCoolingOperation should set it to SupplyAirFlowRate

Steps to Reproduce

m = Model.new
u = AirLoopHVACUnitarySystem.new(m)
u.setSupplyAirFlowRatePerFloorAreaDuringCoolingOperation(0.1)
# => true
u.supplyAirFlowRateMethodDuringCoolingOperation.empty?
# => false
u.supplyAirFlowRateMethodDuringCoolingOperation.get
# => ""

Possible Solution

Straightforward.

Details

Environment

Some additional details about your environment for this issue (if relevant):

• Platform (Operating system, version): All
• Version of OpenStudio (if using an intermediate build, include SHA): develop circa 3.5.0-alpha, 92da27b

Context

Found while adding a new regression test. cf NREL/OpenStudio-resources@2057e0d

[joseph-robertson]

Shouldn't u.supplyAirFlowRateMethodDuringCoolingOperation.is_initialized return false (i.e., u.supplyAirFlowRateMethodDuringCoolingOperation.get shouldn't return "")? Perhaps this is because there is no default specified in the idd choice field?

[joseph-robertson]

I think we just need to use getString(xxx, false, true) for the getters (like fanPlacement()). I.e., "No default, and return uninitialized if empty".