CAV system water coil controller Energy plus

asked 2018-08-20 04:39:27 -0600

Siva gravatar image

updated 2018-08-20 09:52:30 -0600

I am Modelling a CAV system in Energy plus. I am using Chiller. I am trying to put a set point near the Mixed air inlet or at the return air temperature. I want chilled water actuator to operate based on the thermostat temperature. software is not accepting chilled water actuator operation based on either return air temperature/Mixed air inlet. instead it is only accepting a cooling coil outlet based setpoint which is Fine for VAV systems but it cannot be the case for CAV systems. In CAV system the supply air temperature cannot remain constant. the supply air temperature keeps on changing depending upon the load that is prevailing inside the room (Return air temperature) other wise one will end up in overcooling if the setpoint is based on cooling coil outlet during part load conditions.

So Keeping the above thing in view, can any one suggest me how to place this controller ?

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How about you use a SetpointManager:Warmest on the supply outlet node of the PlantLoop, and ensure your fan is constant volume and your AirTerminals are of the "ConstantVolume" type?

Julien Marrec gravatar imageJulien Marrec ( 2018-08-20 06:42:54 -0600 )edit

@ Julien Marrec. could you please give me another hint on how it would resolve my issue.....Like what is that you want to do regarding supply outlet node of the plant loop?

Siva gravatar imageSiva ( 2018-08-20 07:06:19 -0600 )edit

You can control your plant loop as you wish (or per the control sequence of your project). eg: if set it to a constant supply temperature of 45°F, the AHU Coil will vary the ChW flow based on the water temperature and the load it's seeing (which will vary the flow on the plantLoop as a result too).

Julien Marrec gravatar imageJulien Marrec ( 2018-08-22 02:25:37 -0600 )edit