[Equest-users] eQUEST 3.65 build 7175 VRF heating COP input

[Danny Xu]

Here attached the excel with a bit more description, hope it helps.

Anyone has a different idea to input a heating COP for a VRF system,
please discuss it.


On Mon, 25 Aug 2025 at 08:55, Riley, Evan P
<Evan.Riley at masonandhanger.com> wrote:
>
> Hey Danny,
>
> This is interesting and I'd love to try and apply this some time. I'm having trouble deciphering the purpose of, and source of numbers for, each of the three tables. A little more explanation around each would be really helpful I think. Also, some definitions, such as the meaning of "SST" and "SDT." I haven't tried modeling VRFs in eQUEST in quite a few years, so while I'm sure I could dig into the eQUEST documentation to figure all that out, maybe a bit more description within your workbook would make that easier.
>
> Thanks again for sharing this.
>
> Evan Riley PE, BEMP, LEED AP BD&C
> Sr. Energy Engineer, Building Sciences Studio | Mason & Hanger
> O 804.822.3008
>
>
> -----Original Message-----
> From: Danny Xu <dannyxu576 at gmail.com>
> Sent: Friday, August 22, 2025 10:41 AM
> To: equest-users at lists.onebuilding.org
> Subject: [Equest-users] eQUEST 3.65 build 7175 VRF heating COP input
>
> Hello,
>
> I’m currently modeling a VRF system in eQUEST 7175. The equipment cut sheets include both cooling EER and heating COP values. However, I noticed that the VRF condensing unit input in eQUEST only allows for cooling efficiency—there’s no direct field for heating COP.
>
> I looked into this and wasn’t able to find any documentation or settings that allow for a direct input of heating COP.
>
> Here’s the approach I’ve taken to work around this:
>
> For compressor energy consumption in cooling, heating, or combined modes, I’m using the following formula:
>
> P = Prated × EIR_FPLR × EIR_FT × CAP_FT
>
> The default performance curves applied are:
>
> VRF044-Cap-fSST&SDT
>
> VRF044-EIR-fSST&SDT
>
> VRF044-EIR-fPLR
>
> Energy consumption is calculated as follows:
>
> At cooling SST & SDT → based on cooling EER
>
> At heating SST & SDT → based on heating COP
>
> So, instead of directly inputting both cooling and heating EIR values, I rely on:
>
> Cooling EIR
>
> Cooling SST & SDT (used to calibrate the default curve)
>
> Heating SST & SDT (used to reflect heating performance through the same default curve)
>
> A detailed breakdown of the calculations is provided in the attached Excel file.
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