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Ground source heat pump system operation

asked 2023-05-06 11:06:18 -0500

Qamar's avatar

updated 2023-05-07 07:06:14 -0500

I am running a model of ground source heat pump system with central forced air system in EnergyPlus, and I am obtaining the following inlet and outlet temperature curves of the heat pump cooling and heating component.

How can I verify if it is working well?.!

It seems strange that the inlet temperature and the outlet temperature does not match when the heat pump is not operating.

Here it is a link for the two pictures and the model if anyone can help.

https://drive.google.com/drive/folder...

Many thanks in advance.

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answered 2023-05-06 12:58:25 -0500

Keigo's avatar

I don't know which output variables your are looking at. The inlet temperature and the outlet temperature match when the heat pump is not operating.

I picked up just the first one week of your simulation result. image description

My markups (red circles) show that the inlet temperature (the grey line) and the outlet temperature (the black line) match when the heat pump is not operating (when both the sky blue line and the orange line are zero).

The simulation result is here.

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Many thanks for your answer. In fact, I was looking at the temperature at the system nodes 30, 31, 32 and 33 which are the nodes of the inlet and the outlet water temperature of the heat pump on cooling and heating.

On the other hand, I do not know why the central forced air system does not help the heat pump in achieving the thermal comfort in the thermal zones which is 20ºC in winter and 25ºC in summer as it is supposed. For my model now I still have high heating hours not met setpoint. What parameters i need to modify in the model to reduce the not met setpoint heating hours.

Many thanks

Qamar's avatar Qamar  ( 2023-05-07 06:34:29 -0500 )edit
1

What parameters i need to modify in the model to reduce the not met setpoint heating hours.

That is another question. Wasn't my previous comments helpful? Or have you checked many tips listed in this old post?

Keigo's avatar Keigo  ( 2023-05-07 07:27:55 -0500 )edit

Thank you for your answer.

I have corrected the model previously following your previous helpful comments, but I am still obtaining high heating not met hours specially in the three zones of the Auditorium Air Loop.

I was wondering why the model is not able to achieve the thermal comfort and heat the thermal zones enough to achieve 20ºC in winter.

Qamar's avatar Qamar  ( 2023-05-07 13:26:44 -0500 )edit

Regarding the previous question, the inlet and the outlet water temperature of the heat pump which are presented in the two pictures in the link below: https://drive.google.com/drive/folder... still does not match while heat pump is off, I would like to know of what do you think about it please? Many thanks in advance,

Qamar's avatar Qamar  ( 2023-05-07 13:33:11 -0500 )edit
1

The temperature difference between NODE 30:System Node Temperature and NODE 31:System Node Temperature while heat pump is off does not matter because System Node Mass Flow Rate is 0 and Heat Pump Electricity Rate is 0 while heat pump is off. If you still stick to how System Node Temperature is displayed while System Node Mass Flow Rate is 0, you can report it here to the EnergyPlus developers as a bug report.

Keigo's avatar Keigo  ( 2023-05-07 19:44:12 -0500 )edit

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Asked: 2023-05-06 11:06:18 -0500

Seen: 87 times

Last updated: May 07 '23