Heating Loads in dehumidification model

asked 2021-11-01 22:19:21 -0500

Cold wong
67 ●1 ●8

updated 2021-11-03 00:53:26 -0500

I'm researching RH control between split air conditioning and desiccant wheel, but now it confused me. In split air conditioning model, AirLoopHVAC:UnitaryHeatPump:Air to Airhas been added to simulate the actual buildings; the desiccant wheel model is similar as examplefiles DesiccantDehumidifierWithCompanionCoil.idf. This two model both has thier independent heating coils to meet heating loads, and both reheat/regenerated coil to dehumidification. But the heating energy between two models has a big difference in all year. image description What could go wrong in those two models?

Update:This screen capture was RH about desiccant wheel(Setpoint=50%RH). In winter(hot and humid weather's winter), RH obtained a bad control. image description

answered 2021-11-02 10:22:00 -0500

ericmartinpe

2065 ●42 ●8 http://ericmartinpe.com/

At least part of the reason is the different heating fuels - the unitary heat pump uses a DX coil (electricity) and the DesiccantDehumidifierWithCompanionCoil model uses all gas furnace coils. The heat pump will use less energy (COP > 2) compared to furnace (COP ~ 0.8).

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Thanks for your answer, but heating coils are both DX single speed with a similar COP. Reheat/Regen coils were electric.

Cold wong ( 2021-11-03 00:14:48 -0500 )edit

You mentioned the DesiccantDehumidifierWithCompanionCoil example file, which has gas furnace heating coils. It's difficult to diagnose your issue without access to your actual IDFs. Consider posting links to your IDFs so others can investigate.