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[EnergyPlus_Support] Re: Coil water flow rate control (Coil:Heating:Water)

Thanks for your reply Dr Li,

Running a simulation using a weather file gives a dynamic and realistic load. 

In a real system, however, a fan coil unit cannot possibly know the load; control will be based on sensor data - likely room air temperature. 

The "control" I want to implement is a realistic one i.e. a coil with sufficient to meet and exceed the max load, such that the fan will always run and the water will bypass or flow through the coil, depending on room temperature, or a PID controller could be used.

There are also capacity control possibilities - matching water capacity with air capacity, depending on different air and water flow rates and supply temperatures.

Essentially, I want the possibility to implement something like

"IF sensor_signal > upper_boundary && bypass = 0
     SET coil_flow_actuator = desired_flow_rate
 ELSEIF .....

END"

I know this can done via EMS for pumps and fans, but I can't see any possibility for coils.

Thanks

Aidan





--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> If you want to control the flow etc. yourself without knowing the demand changes, etc., why bother to run the simulation usint the weather file. EPlus is controlling the heat transfer according to the heat demand calculated.  If you mismatch them, the result will be set point not met. When you change the set-point temperature of the boiler or the zone, or the ODT, the flow rate will change.
> What is the "control" you wanted to have?  If you are thinking of generating the performance curve using EPlus by controlling the flowrate and calculate the heat transferred, it is a different programming input requirement.   Think of what you do in a lab.  You will need all those information as input.  There is no EPlus simulation short cut, without the necessary input data. The Engineering Ref. Manual do have some information on how to generate the heat transfer properties of some heat exchanger types.
>  Dr. Li   
>  To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: jones.aidan.t@...
> Date: Thu, 12 Apr 2012 19:05:18 +0000
> Subject: [EnergyPlus_Support] Coil water flow rate control (Coil:Heating:Water)
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> EnergyPlus will automatically control the capacity of fan coil units (as part of unitventilator, etc) by modulating the water flow through the coil, leading to constantly varying water flow and heat transfer. 
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> Is there a way (via EMS or otherwise) for the user to control the water flow through the coil? If not, is there some way to control the heat transferred in the coil?
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> Many thanks 
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> Aidan
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