[Equest-users] Supply Air Temp Reset Interpretation Please...?

Shaun Martin via Equest-users equest-users at lists.onebuilding.org
Thu Apr 20 07:29:42 PDT 2017



I think the Standard is quite clear about resetting temperature, and says nothing about modulating airflow.  The user manual seems to be wrong.


Shaun Martin LEED-AP, BEMP


Shaun Martin Consulting

#90 – 425 Carrall Street

Vancouver, BC  V6B 6E3

p. 604-789-1095





From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of PKConsulting via Equest-users
Sent: Thursday, April 20, 2017 7:12 AM
To: Jones, Christopher <Christopher.r.Jones at wspgroup.com>
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Supply Air Temp Reset Interpretation Please...?


Thanks for the feedback-  so if the justification for the approach is solely based on the user manual explanation- I can accept that.  I'll cross reference it for the 2007 user manual to put it in my notes.


I've always used air-flow first as a standard reset for all my design energy models, What is counter-intuitive here is that the title of the Appendix G section specifically states 'reset-temp', so why should we not take the section text literally?  I've always humbly assumed that the ASHRAE standard writers know more than me.  After all these years of creating Baseline conforming models (or so I thought),  this makes me feel lost all over again.  AND is it not possible to apply code standard requirements without the use of the User Manual?   


Thankful- but-frustrated,


Ph: 308-763-1593

On Apr 20, 2017, at 6:48 AM, Jones, Christopher <Christopher.r.Jones at wspgroup.com <mailto:Christopher.r.Jones at wspgroup.com> > wrote:

I had always assumed temperature first but reading the PNNL 90.1-2010 Performance Rating Method Reference Manual, 3.121 (pdf page 151), it states “For systems 5 through 8, the air temperature for cooling shall be reset higher by 5°F under the minimum cooling load conditions using a reset by warmest zone, airflow first strategy.”


The manual states that the airflow first strategy minimizes zone reheat coil energy ( or overcooling) and central chiller energy consumption at the cost of possible increased fan energy. 


Unfortunately, the reviewer may have a case. 





Christopher R. Jones, P.Eng.

Technical Specialist


WSP Canada Inc.
2300 Yonge Street, Suite 2300

Toronto, ON M4P 1E4 Canada
T +1 416-644-0252


 <http://www.wspgroup.ca/> www.wspgroup.ca


Please consider the environment before printing...



From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Pasha Korber-Gonzalez via Equest-users
Sent: Thursday, April 20, 2017 3:59 AM
To: eQUEST Users List <equest-users at lists.onebuilding.org <mailto:equest-users at lists.onebuilding.org> >
Subject: [Equest-users] Supply Air Temp Reset Interpretation Please...?


Hello--- I received this note from a fellow energy model reviewer (non-LEED review comment) regarding my Baseline energy model that is supposed to be compliant with Appendix G.  I disagree with what they are saying.  I appreciate your feedback please and verification if in fact I am wrong in how I am interpreting Section G3.1.3.12.



"We believe TEMP-FIRST supply air reset control strategy is not the correct interpretation of G3.1.3.12 – rather, AIRFLOW-FIRST should be used."






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