[Equest-users] Heat Pump Chiller - Anyone know the Rating Conditions

[Bill Bishop]

Hi Chris,

Are you running DOE2.2 or DOE2.3?

Looking through the DOE2.2 Vol2 Dictionary, there is a note that, “the performance curves are normalized at the Eurovent rating conditions, rather than ARI.” For HEAT-EIR-FT, “this curve should be normalized to 1.0 at the ARI or Eurovent rating point” but I don’t know what temp that is (or was, in 2009).

With DOE2.3, HEAT-EIR-FT, “the value of the curve is usually normalized to 1.0 at rated conditions, but this is not mandatory; the program will normalize the curve internally”.
In DOE2.3 mode, the default value for RATED-COND-T-HT is 45F based on the default expression for an air-cooled condenser. The default for RATED-HW-T is 110F.
You can experiment by creating a custom hourly report block with variable type Chiller that reports leaving supply temperature, entering condenser temperature and correction to heat-input-ration for temperature.

Regards,
~Bill


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From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of Chris Hadlock via Equest-users
Sent: Wednesday, May 20, 2026 10:20 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Heat Pump Chiller - Anyone know the Rating Conditions

External Email: Treat links and attachments with caution.
Hi All,

I'm modeling a "heat pump" type chiller (air-cooled) and I'm trying to figure out the dependent variables about which the default curves are normalized so that I can create my own curves. Below is the screen-shot for my heat pump Performance Curves.
[cid:image001.png at 01DCE887.42E364E0]
For example, the heating EIR curve that is a function of evap leaving T (SWT) & cond entering T (OAT): does anyone know the leaving water temperature and entering air temperature at which point this curve is normalized (i.e. returns an EIR value of 1.000)? I used goal seek for various combination of temperatures and here are some options (yellow cell was calculated using GOAL-SEEK ):

SWT ->
120
115
115.6816
105
112.2388
OAT ->
54.36586
61.10728
47
39.21
44
Goal Seek set to 1.000 ->
1.003649
0.999675
0.99995
1
0.999975

Based on these results, it's looking like perhaps 115F SWT and 47F OAT might be correct...but wanted to confirm.

Since there is a second heating EIR curve for OAT < 39F, does anyone know the leaving water temperature and entering air temperature at which point this curve is normalized?

Thanks,
Chris
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