Modeling Fan Static Pressure Reset in eQuest

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Hello Guys,What is the best way to model fan static pressure reset in eQuest software?RegardsAhmadSent from my Galaxy

Ahmad Fraij's picture
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Hi Ahmad,

I typically model this using the fan curves from the PNNL 90.1 2016 PRM
Reference Manual. I provided some screenshots below.

[image: image.png]

[image: image.png]

Christina

*Christina LaPerle* PE, BEMP, CEM, CBCP
Senior Energy Engineer, Associate
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On Thu, Sep 9, 2021 at 7:47 AM fraij via Equest-users <

Christina LaPerle's picture
Joined: 2019-12-11
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Nice find Christina!
All,
I compiled the three fan curves at the bottom of Table 50 into the attached input file. You can load them into your eQUEST models using File -> Import File?
A few comments about use of these curves with Appendix G modeling in eQUEST:

* Static pressure reset control is a prescriptive requirement in 90.1-2016 6.5.3.2.3. Therefore, most proposed designs should include SP reset and supply fans should be modeled using the ?MZVAV Good SP Reset Fan Curve? attached.
* The ?Multi Zone VAV with VSD and fixed SP setpoint? curve in Table 50 is the same curve required by Appendix G. Supply fans for Baseline System Types 5 through 8 should be modeled with this fan curve.
* Appendix G3.1.3.15 says the same curve applied to Systems 5 through 8 should be applied to Baseline System 11. However, the PNNL PRM Reference Manual p.3.154 says use the ?Single zone VAV fan? curve which is based on perfect static pressure reset and uses the least energy of all the Table 50 curves.
* Up until now, I have always used the same fan curve for both supply and return fans (SYSTEM:FAN-EIR-FPLR and SYSTEM:RETURN-EIR-FPLR). However, the PRM Reference Manual p.3.158 says use the ?Multi zone VAV with static pressure reset curve? for Baseline Systems 5 through 8 and 11. I don?t know if this is an error or if there is logic to using a more efficient fan curve for return fans.
* Table 50 also has a column for %Powermin, or minimum fan power as a percent of full load power. The values are 20% for MZVAV with fixed SP setpoint (the standard App.G curve) and 10% for the two static pressure reset curves. However, Appendix G also requires minimum volume set points of 30% for Baseline Systems 5 through 8 and 50% for System 11 (entered in eQUEST using ZONE:MIN-FLOW-RATIO and which should also be adjusted for minimum OA if necessary). The combination of MIN-FLOW-RATIO and fan curve will dictate the minimum fan power percentage instead of the %Powermin.
Regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer
[Pathfinder-EA-logo-2][Logo Description automatically generated]
T: (585) 698-1956 F: (585) 325-6005
bbishop at pathfinder-ea.com www.pathfinder-ea.com
134 South Fitzhugh Street
Rochester, NY 14608 [cid:image008.png at 01D7A56B.F1A253B0] Ask me why Carbon Fee & Dividend may be right for you.

Bill Bishop's picture
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Thanks Christina and Bill for your help, but I have the following two questions:

- Does using a fan curve for static pressure reset reflect the actual operation of this control strategy? I mean, the operation of this control strategy depends on the building type, thermal load, building location...etc but if all of us use the same fan curve to represent it in eQUEST, will that gives accurate results?
- Where can I find appendix G for modeling?

Regards
Ahmad
On Friday, September 10, 2021, 01:55:52 AM GMT+10, Bishop, Bill wrote:

Nice find Christina!

All,

I compiled the three fan curves at the bottom of Table 50 into the attached input file. You can load them into your eQUEST models using File -> Import File?

A few comments about use of these curves with Appendix G modeling in eQUEST:

- Static pressure reset control is a prescriptive requirement in 90.1-2016 6.5.3.2.3. Therefore, most proposed designs should include SP reset and supply fans should be modeled using the ?MZVAV Good SP Reset Fan Curve? attached.
- The ?Multi Zone VAV with VSD and fixed SP setpoint? curve in Table 50 is the same curve required by Appendix G. Supply fans for Baseline System Types 5 through 8 should be modeled with this fan curve.
- Appendix G3.1.3.15 says the same curve applied to Systems 5 through 8 should be applied to Baseline System 11. However, the PNNL PRM Reference Manual p.3.154 says use the ?Single zone VAV fan? curve which is based on perfect static pressure reset and uses the least energy of all the Table 50 curves.
- Up until now, I have always used the same fan curve for both supply and return fans (SYSTEM:FAN-EIR-FPLR and SYSTEM:RETURN-EIR-FPLR). However, the PRM Reference Manual p.3.158 says use the ?Multi zone VAV with static pressure reset curve? for Baseline Systems 5 through 8 and 11. I don?t know if this is an error or if there is logic to using a more efficient fan curve for return fans.
- Table 50 also has a column for %Powermin, or minimum fan power as a percent of full load power. The values are 20% for MZVAV with fixed SP setpoint (the standard App.G curve) and 10% for the two static pressure reset curves. However, Appendix G also requires minimum volume set points of 30% for Baseline Systems 5 through 8 and 50% for System 11 (entered in eQUEST using ZONE:MIN-FLOW-RATIO and which should also be adjusted for minimum OA if necessary). The combination of MIN-FLOW-RATIO and fan curve will dictate the minimum fan power percentage instead of the %Powermin.

Regards,

~Bill

?

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

Senior Energy Engineer

T: (585) 698-1956???????????????????????F: (585) 325-6005

bbishop at pathfinder-ea.com????????www.pathfinder-ea.com

134 South Fitzhugh Street

Rochester, NY 14608?????????????????????Ask me why Carbon Fee & Dividend may be right for you.

?

Ahmad Fraij's picture
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Hello Guys,What is the best way to model fan static pressure reset in eQuest software?RegardsAhmadSent from my Galaxy

Ahmad Fraij's picture
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Joined: 2020-10-13
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