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How to control the temperature of hot water on the heating coil in EnergyPlus

asked 2015-07-06 03:45:10 -0500

ndongyang gravatar image

I want know if we can control the temperature about the heating coil outlet . I use the DistrictHeating as the heat source .The supply heat water temperature is 60 ℃,but the heating coil outlet temperature is only about 25 ℃. So I think the outlet temperature is too low.

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answered 2015-07-07 10:41:38 -0500

Hi, why do you want to control the temperature at the outlet? Depending on your air temperature in and our of your coil (according to the settings you have on your AHU or room thermostat), the flow rate of the air and your water flow rate will all affect the temperature of the water exiting the coil.

If you really need to set the temperature there I think you could put a setpoint on it, maybe try first with a scheduled setpoint. I am not sure if this would work but it would be something to try.

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@Annie Marston: If he really needs to do this then what about using EMS sensors and actuators?

Waseem gravatar image Waseem  ( 2015-07-07 12:35:05 -0500 )edit

I agree with Annie. This is expected behaviour of heating coil at part load operation when the coil's heat output is controlled by varying hot water flow rate. Part of the hot water is bypassed and you will have smaller than designed temperature drop in the whole plant loop. Check the temperature at inlet of the DistrictHeating system. Such a coil behaviour is caused by fixed physical parameters of the coil (in the case of simple hot water coil: UA at designed flow rate, nominal capacity, design in/out temperatures both air and water, etc.).

Ivan Korolija gravatar image Ivan Korolija  ( 2015-07-07 14:23:15 -0500 )edit

Thank you very much! The system of my model use a ConstanPump and I find the water flow rate of the bypass is too big so must heat energy loss. The coil model is Coil:Heating:Water.I put a setpoint use the SetpointManager:Schedule but the temperature of outlet still 25℃.

ndongyang gravatar image ndongyang  ( 2015-07-08 02:47:04 -0500 )edit

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Asked: 2015-07-06 03:45:10 -0500

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Last updated: Jul 07 '15