HEAT-EIR-FT for heat pumps with water cooled condensers?

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I am modelling a building with distributed water loop heat pumps. I am
looking at the electricity used for space heating (the compressor energy in
heating mode). This depends on a part load curve HEAT-EIR-FT which is a
function of two temperatures. Based on the DOE2 documentation, it is not
clear to me which two temperatures this curve is using to modify the
compressor energy for a water-cooled heat pump.

For an air-cooled heat pump, the curve is a function of entering dry-bulb
temperature and outdoor dry-bulb temperature. I want to know what the X and
Y values are for a water-cooled heat pump.

Can anyone provide any clarification on this?

Many thanks.

Brian

bfountain's picture
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Reputation: 201

Brian,

It looks to be EDB and EWT for heating (and EWB and EWT for cooling), refer to the attached from the DOE2.2 Dictionary.

Regards,
Aaron

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Brian,
I agree that the DOE2 documentation is not very clear on your question. I believe Aaron is correct. Water-source heat pumps use EDB/EWT for HEAT-EIR-FT and EWB/EWT for cooling. In the DOE2.2 Dictionary entry that Aaron attached, the suffix of the GSHP/WLHP heating curve names is "fEwb&Ewt", which implies wet bulb temperature is used but I believe this to be in error. I looked at this when I created my own performance curves. I looked at hourly reports for temperature, humidity, temperature correction to power and power, compared these to the predicted output using the default GSHP/WLHP curves and determined that wet bulb temperature is used in cooling and dry bulb temperature is used in heating. Plus, it wouldn't make sense to use wet bulb temperature for the heating curves because no latent energy is added or removed during the heating process.
Regards,

William Bishop, PE, BEMP, BEAP, CEM, LEED AP

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Entering indoor wet bulb and entering (condenser) water temperature I
believe.

Anthony Hardman, PE, LEED AP BD+C

Anthony Hardman, PE
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Thank you all for the replies. I did receive a definitive answer:

"Entering mixed air temperature to the indoor coil(s) and entering fluid
temperature for the water side."

Plus, I received the excellent guidance from Aaron pointing out the
differences in the "HP- " series part load curves which are normalized on
ARI conditions and the "GSHP/WLHP- " series part load curves which are
normalized on GSHP loop conditions and require modifications to the EIR and
capacity. The "GSHP/WLHP- " are the defaults coming out of the wizard.

Cheers,

bfountain's picture
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Joined: 2011-09-30
Reputation: 201