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Air Source Heat Pump Curves

asked 2014-12-15 18:52:54 -0600

Gilles CR's avatar

updated 2014-12-16 09:23:35 -0600

keb's avatar

I seeking for an excel spreadsheet that calculate biquadratic equation coefficients given an array of air temperature, water conditions, capaicities and COPs. This is to input into the Energyplus curve table.

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What type of ASHP are you interested in? Commercial? Residential? Traditional split-system? Mini-split?

Eric Wilson's avatar Eric Wilson  ( 2014-12-16 10:12:32 -0600 )edit

I would be interested in Commercial type Air to water for a commercial building.

Gilles CR's avatar Gilles CR  ( 2014-12-16 14:17:57 -0600 )edit

I am looking for this as well...I have a Multistack air-cooled heat pump chiller.

Anna Osborne Brannon's avatar Anna Osborne Brannon  ( 2015-06-18 12:42:40 -0600 )edit

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answered 2014-12-18 16:16:53 -0600

updated 2014-12-18 16:23:57 -0600

In your EnergyPlus install folder, \PreProcess\HVACCurveFitTool\CurveFitTool.xlsm Even though it is intended for air-to-air, you should be able to adjust the inputs to match water temperatures on either side.

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While I haven't looked at that spreadsheet, I would think air-to-water heat pumps can see a much wider range of return water temperatures (up to 120ºF or higher), compared to the relatively constant return air temperature that air-to-air heat pumps see (around room temperature, perhaps with some outdoor air mixed in). I would be cautious about using air-to-air curves for an air-to-water heat pump.

Eric Wilson's avatar Eric Wilson  ( 2015-02-03 10:46:32 -0600 )edit

The range of temperatures expected during the simulation (air or water) can be entered in the curve fit tool such that the performance curve coefficients accurately represent performance.

rraustad's avatar rraustad  ( 2015-07-25 00:34:49 -0600 )edit

Is there an example that shows how to "adjust the inputs to match water temperatures on either side"?

Gio's avatar Gio  ( 2017-01-09 10:28:37 -0600 )edit

No example that I'm aware of.

MJWitte's avatar MJWitte  ( 2017-02-02 09:31:20 -0600 )edit

I think there is no adjustement to do. The names "Outdoor air T ( C)" "Leaving condenser water T ( C)" are just labels for this proposed example. You have to read them as "Indipendent variables" and so they can be outdoor air temperature and water outlet temperature without any change.

Gio's avatar Gio  ( 2017-03-28 10:03:53 -0600 )edit

answered 2014-12-16 09:21:41 -0600

keb's avatar

See the following link from EnergyPlus helpdesk website:

There is a zip file with excel spreadsheets and pdf instructions.

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That link appears to be for WatertoWater or WatertoAir heat pumps. Did you mean to link to a different page for AirtoAir heat pumps?

Eric Wilson's avatar Eric Wilson  ( 2014-12-16 10:10:07 -0600 )edit

I'm think Gilles meant to say water to air. :)

keb's avatar keb  ( 2014-12-16 10:58:22 -0600 )edit

It's actually air to water. Does this still apply?

Gilles CR's avatar Gilles CR  ( 2014-12-16 14:18:47 -0600 )edit

We might be having a semantics problem. Describe the equipment; what function is being performed?

keb's avatar keb  ( 2014-12-18 11:04:41 -0600 )edit

Heat is taken from or rejected to the air from the source side and the heat pump is connected to an hydronic circuit on the building side.

Gilles CR's avatar Gilles CR  ( 2014-12-29 23:23:37 -0600 )edit

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Asked: 2014-12-15 18:52:54 -0600

Seen: 1,067 times

Last updated: Dec 18 '14