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Dehumidification control on packaged unitary in Energy Plus

asked 2014-12-01 16:13:50 -0600

E Boxer's avatar

updated 2015-07-11 13:07:32 -0600

I am attempting to use a dedicated outdoor air unit (Packaged Unitary HVAC) in energyplus 8.0 so that it does sub-cooling of outdoor air in response to zone humidity levels rising above a humidity threshold. Currently, the "Dehumidification Control Type" is set to "CoolReheat", there is a humidistat in the control zone, and a maximum humidity schedule has been defined at 50%.

Per the I/O manual, I created a TwoStagewithHumidityControl coil and was able to associate this with the desuperheater. However, I am not able to see the option to connect the TwoStageWithHumidityControl coil on the drop-down list of cooling coil choices for the system. When I enter the coil name manually, multiple errors arise. Among them, "Illegal Cooling Coil Object Type=Coil...HumidityControl"

Is this the right approach to basic humidity control? Anyone know what's going on here?

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answered 2014-12-03 12:48:21 -0600

This depends on your equipment type. Coil:Cooling:DX:TwoStageWithHumidityControlMode models a system which has two operating modes, normal and subcool reheat (altered SHR). This coil is supported by AirloopHVAC:UnitarySystem, AirLoopHVAC:UnitaryHeatCool:VAVChangeoverBypass and CoilSystem:Cooling:DX. If you are modeling a standard single-speed DX coil which simply runs longer to overcool and dehumidify, then you can use Coil:Cooling:DX:SingleSpeed with AirLoopHVAC:UnitaryHeatCool.

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Thank you, your comment is greatly appreciated and got me on the right track. The first problem was in using e+ 8.0. Energyplus 8.1 and 8.2 have been updated to allow the use of TwoStageWithHumidityControl coils on the system type AirLoopHVAC:UnitarySystem. It is still not available with the UnitaryHeatCool system type.

E Boxer's avatar E Boxer  ( 2014-12-03 14:44:01 -0600 )edit

answered 2014-12-03 11:01:00 -0600

E Boxer's avatar

updated 2014-12-03 14:45:57 -0600

According to the I/O manual, the TwoStageWithHumidityControl coil type is not allowed on systems of type UnitaryHeatCool. The best option would be to simulate with another system type. In energyplus 8.1 and onwards, the TwoStageWithHumidityControl coil type is allowed with system type "AirLoopHVAC:UnitarySystem", which also has other extended capabilities beyond those found in the "UnitaryHeatCool" system type.

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Asked: 2014-12-01 16:13:50 -0600

Seen: 474 times

Last updated: Dec 03 '14