Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

Heating Loads in dehumidification model

asked 2021-11-01 22:19:21 -0600

Cold wong's avatar

updated 2021-11-03 00:53:26 -0600

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 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

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2021-11-02 10:22:00 -0600

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).

edit flag offensive delete link more


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

Cold wong's avatar Cold wong  ( 2021-11-03 00:14:48 -0600 )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.

ericmartinpe's avatar ericmartinpe  ( 2021-11-04 10:54:44 -0600 )edit

Thansk, It is the link to my IDF. (

Cold wong's avatar Cold wong  ( 2021-11-05 01:31:46 -0600 )edit

Can you post the other IDF so we can compare to see what's different between the two (isn't that your question)?

ericmartinpe's avatar ericmartinpe  ( 2021-11-11 11:53:13 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools

1 follower


Asked: 2021-11-01 22:19:21 -0600

Seen: 139 times

Last updated: Nov 03 '21