Modelling Constraint for Coil:Cooling:WaterToAirHeatPump

asked 2024-12-13 03:48:58 -0600

Keigo
4111 ●1 ●48 ●21 https://www.linkedin.c...

updated 2024-12-16 14:09:59 -0600

14250 ●86 ●24 http://bigladdersoftware.com/

I want to use Coil:Cooling:WaterToAirHeatPump:EquationFit in a normal air loop i.e. AirLoopHVAC. I entered the Coil:Cooling:WaterToAirHeatPump:EquationFit object in Branch, and I got the following severe error. EnergyPlus is V24-1-0.

   ** Severe  ** GetAirPathData: AirLoopHVAC = "CRAH".
   **   ~~~   ** ..Invalid Air Loop Component Type = "COIL:COOLING:WATERTOAIRHEATPUMP:EQUATIONFIT".
   **   ~~~   ** ..Air Loop Component Name = "DX COOLING COIL".
   **   ~~~   ** ..reference Branch = "CRAH MAIN BRANCH".
   **  Fatal  ** GetAirPathData: Errors found retrieving input for AirLoopHVAC.
   ...Summary of Errors that led to program termination:

IDF Editor shows the object in a drop-down list in Branch, so I thought we can use it, but the error says it is invalid.

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When I check ExampleFiles, Coil:Cooling:WaterToAirHeatPump:XXX object is always used with AirLoopHVAC:UnitaryHeatPump:waterToAir. Do we have to use Coil:Cooling:WaterToAirHeatPump:XXX with AirLoopHVAC:UnitaryHeatPump:waterToAir? I don't want to use AirLoopHVAC:UnitaryHeatPump:waterToAir because it allows Fan:OnOff only. My system is variable air flow. Is there any way to use Coil:Cooling:WaterToAirHeatPump:XXX without AirLoopHVAC:UnitaryHeatPump:waterToAir?

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Hi Keigo, I'm a design builder user who often wants to use water to air coils. I can access these coils from two objects: the unitary heat pump: water to air, or (what design builder calls) generic unitary system air loop. https://bigladdersoftware.com/epx/doc... In the later object, you can have variable air flow. I think the E+ object is called AirLoopHVAC:UnitarySystem https://bigladdersoftware.com/epx/doc...

Greg Estep ( 2024-12-13 09:33:20 -0600 )edit

@Greg Estep Thanks. Right, I also self-resolevd.

Keigo ( 2024-12-13 09:51:04 -0600 )edit

@Greg Estep Btw, can DesignBuilder add a precooling coil in front of the unitary heat pump: water to air or generic unitary system? We can model the precooling coil with IDF Editor, but I'm not sure if we can also model it with DB.

Keigo ( 2024-12-13 09:59:27 -0600 )edit

@Greg Estep I mean for supply air precooling just upstream of the unitary system, not for outdoor air precooling.

Keigo ( 2024-12-13 11:04:42 -0600 )edit

No. I can only place a coil in the outdoor air inlet box (upstream of the mixing damper) Is your AHU just recirculating (no ventilation)?

Greg Estep ( 2024-12-13 12:00:39 -0600 )edit

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