[Equest-users] DOE 2.3 VRF Heating Efficiency?

[Bishop, Bill]

Hi Matt,
See my previous email copied below which gives more background on VRF heating efficiency.
Regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer

[Pathfinder-EA-logo-2]T: (585) 698-1956                        F: (585) 325-6005
bbishop at pathfinder-ea.com<mailto:wbishop at pathfinder-ea.com>        www.pathfinder-ea.com<http://www.pathfinder-ea.com/>
134 South Fitzhugh Street
Rochester, NY 14608               [cid:image003.png at 01D65441.DFA6DB30]         Ask me why Carbon Fee & Dividend may be right for you.

From: Bishop, Bill
Sent: Wednesday, June 5, 2019 8:44 AM
To: Porter, Frederick NOR <fporter at noresco.com>
Cc: equest-users at lists.onebuilding.org
Subject: RE: VRF Heating COP in eQUEST

Hi Fred,
For VRF condensing units in eQUEST, the heating EIR is a function of other variables. You can use the following keyword expression to determine the heating EIR that is used by eQUEST. It can be entered as a user input expression into one of the other keywords, so you can see how it changes when you change the other variables. (For example, you can enter it as an expression for MIN-UNLOAD-RATIO or MIN-HGB-RATIO, which have default values that are close to the heating EIR, in case you leave the expression in when you simulate.) You can see all the variables that determine the heating EIR in the expression:

/* This expression will calculate the heating EIR that DOE-2.3 will use
   for a VRF condensing unit. You can input this as a user expression
   in another keyword such as MIN-UNLOAD-RATIO. */

#L("COOLING-EIR")*(#LR("EIR-FSST&SDT","COEFFICIENTS",0)
+#LR("EIR-FSST&SDT","COEFFICIENTS",1)*#L("HEAT-RATED-SST")
+#LR("EIR-FSST&SDT","COEFFICIENTS",2)*#L("HEAT-RATED-SST")**2
+#LR("EIR-FSST&SDT","COEFFICIENTS",3)*#L("HEAT-RATED-SDT")
+#LR("EIR-FSST&SDT","COEFFICIENTS",4)*#L("HEAT-RATED-SDT")**2
+#LR("EIR-FSST&SDT","COEFFICIENTS",5)*#L("HEAT-RATED-SST")
*#L("HEAT-RATED-SDT"))
/(#LR("EIR-FSST&SDT","COEFFICIENTS",0)
+#LR("EIR-FSST&SDT","COEFFICIENTS",1)*#L("COOL-RATED-SST")
+#LR("EIR-FSST&SDT","COEFFICIENTS",2)*#L("COOL-RATED-SST")**2
+#LR("EIR-FSST&SDT","COEFFICIENTS",3)*#L("COOL-RATED-SDT")
+#LR("EIR-FSST&SDT","COEFFICIENTS",4)*#L("COOL-RATED-SDT")**2
+#LR("EIR-FSST&SDT","COEFFICIENTS",5)*#L("COOL-RATED-SST")
*#L("COOL-RATED-SDT"))

Remember that fan energy should be accounted for when converting rated EER or COP to EIR. Doug Maddox shows how to calculate VRF EIR in this presentation:
http://maddoxenergy.com/eQuest_DOE23_VRF.pdf
Cooling EIR for the condensing unit: (3.413/AHRI_EER-0.01138)/(1+0.01138)
I believe you would reverse the fan energy for heating. Heating EIR = (1/COP+0.01138)/(1-0.01138)
The constant 0.01138 is the allowance for indoor fan EIR.
Also, I created a modified BDLDialogs.txt file to use with DOE2.3. The file adds these keyword capabilities to the eQUEST interface:

  *   SYSTEM:RATED-FLOW
  *   SYSTEM:HRATED-FLOW
  *   SYSTEM:NUM-COOL-STAGES (for PVVT systems)
  *   SYSTEM:NUM-HEAT-STAGES (for PVVT systems)
  *   SYSTEM:LOW-FAN-PWR (for PVVT systems)
  *   SYSTEM:MAX-CAP/UNIT (for VRF coils)
  *   CONDENSING-UNIT:TYP-CAP/SYSTEM (for VRF condensing units)
The file also adjusts the number of decimal places displayed for several keywords, such as the cooling EIR that you mentioned. I am happy to share this file with eQUEST users (it is ~1.7 MB).
Regards,
~Bill


From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of Matthew S. Garlick via Equest-users
Sent: Friday, July 3, 2020 11:20 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] DOE 2.3 VRF Heating Efficiency?

Howdy folks,

I'm working through an air source VRF system and have found no place to explicitly place a heating efficiency, only the cooling EIR. As far as I can see there's no mention of heating efficiency in the user's manual as well. Can anyone explain how heating efficiency is calculated in 2.3 without the user specifying it?

On a related note, I'm also studying a water source VRF system on this project. Has anyone heard rumors of this being developed in a future version of eQUEST? I'm currently using the WSHP workaround you all helped me put together a year or so ago.

Thanks and have a great 4th of July weekend!


[TBCx]

Matt Garlick, CxA, CEM, BEMP
Principal Commissioning Authority,
Energy Engineer | TBCx

E-mail: msg at tbcxinc.com<mailto:msg at tbcxinc.com>
Mobile: 801-907-5654
Direct: 801-401-9492

324 S. State Street, Suite 400
Salt Lake City, UT 84111


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20200707/876d0a0c/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 9336 bytes
Desc: image001.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20200707/876d0a0c/attachment-0004.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.png
Type: image/png
Size: 1554 bytes
Desc: image003.png
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20200707/876d0a0c/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image004.jpg
Type: image/jpeg
Size: 1903 bytes
Desc: image004.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20200707/876d0a0c/attachment-0005.jpg>