[EnergyPlus_Support] Re: How to model an air-cooled scroll-type heat pump

I am encountering the similar system problems. I would like to simulate the air source heat pump system. And I use HVAC template for VAV system and my air side in the zones follows the template. After I expanded the idf files, I used to use centralheatpump system but failed as the fluid required should be water not air. I am confused how to simulate air source heat pump for cooling and heating source in the plant system level. For cooling I could simluate chiller as air cooled. how about heating?

I used HVAC template with chilled water loop and hot water loop such the default setting is chiller and boiler. When editing the node connections as well as branch and branchlist, is there any suggesstions for connection?

---In EnergyPlus_Support@xxxxxxxxxxxxxxx, <yli006@...> wrote :

There are many heatpump examples in the exampleFiles folder. Try:

HeatPumpWaterToAir.idf

It has water chiller, air condenser, and hot water.

I do not understand why you must follow an example file. FRaw the system diatram that you require, and fit inthe components.

You should have zones, AHU system water cooling and heating coilss and fan, with OA mixer.

Water chiller using heatpump in a Chilled water Plant loop.

Water heater using the same heatpump in the heating mode with auxiliary heaters, if needed, in a Hot water plant loop.

You may have problem naming the nodes, therefore you se a HVAC template for chiller loop and hotwater loop to help. In the chiller template and the HW template, there may be heatpump as the equipment. That is how you learn to use EPlus.

Template is written in a MACRO format, and is ecpanded to .expIDF for simulation. The .expIDF can be rename to IDF and run directtly. After running a few templaes, you can cut and paste the expanded version directly. So. PTHP template will have the air to air heatpump.

Let me know, if you still have problems.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: xing.shi.2006@...
Date: Mon, 1 Oct 2012 00:54:38 +0000
Subject: [EnergyPlus_Support] Re: How to model an air-cooled scroll-type heat pump

Dr. Li,

Thank you for your reply!

As you said, "Heatpump is usually operated with air to air, with the evaporator and compressor coil switched around for coolant and heating in a location that the Winter is not very cold. For a large capacity heatpump, then water is used to feed the AHU coils, and the condenser loop provides more cooling and may use water to feed a tower to help cooling."

The above is exactly our design. The only thing is that we don't have a cooling tower. We do feed water to the AUH coils. However, on the condenser side, it is still air-cooled.

In fact, the system is not complex at all. We just don't know how to model it in E+. There is GSHP in the E+ example files. We believe that the only different is that our design does not use ground source for heat rejection. We simply use outdoor air as the heat sink.

On the scroll compressor thing, you are right, it is just that the performance curve is different.

Our main difficult is that we don't know how to model an air-cooled heat pump which produces hot and chilled water to carry heat to the AHU in EnergyPlus.

Thank you!

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> May I ask what is a "scroll type" compressor. I have not check the data base folder for this type. I think, it is only the performance curves are different in the simulation. As far as I know, it does not matter whether it is a heat pump or an EIR when it is used for chiller only. Condenser is to air, therefore, no condenser loop is required.Your design is a simple water chiller. Coil water to air, means the coil is water and the air flows through the coil surface. If the coolant flows in the coil, then it is a DX coil. Heatpump is usually operated with air to air, with the evaporator and compressor coil switched around for coolant and heating in a location that the Winter is not very cold. For a large capacity heatpump, then water is used to feed the AHU coils, and the condenser loop provides more cooling and may use water to feed a tower to help cooling. Dr. Li
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: xing.shi.2006@...
> Date: Fri, 21 Sep 2012 09:59:11 +0000
> Subject: [EnergyPlus_Support] How to model an air-cooled scroll-type heat pump
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> The design system is as follows:
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> - heat pump
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> - compressor is scroll-type
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> - heat sink is air
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> - heat pump produces chilled water and hot water
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> - cooled or heated air is blown into the zones
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> We are considering using the object Coil:Cooling:WaterToAirHeatPump:ParameterEstimation and Coil:Heating:WaterToAirHeatPump:ParameterEstimation to model the system. However, in the E+ example file folder we could only find examples with ground source heat exchanger as the heat sink. In our case, the heat pump is air-cooled, which means the heat sink is outdoor air. We don't know how to model that. Or, we should use another object?
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> Please help. Thank you!
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