[Equest-users] design flow input vs. SV-A supply flow reporting

Fri Oct 8 13:12:21 PDT 2010

Thanks everyone.

Paul Diglio

________________________________
From: Nick Caton <ncaton at smithboucher.com>
To: Matthew W. Higgins <MWHiggins at bpce.com>; Paul Diglio 
<paul.diglio at sbcglobal.net>; Carol Gardner <cmg750 at gmail.com>; 
cstalberg at naturalintelligence.us
Cc: equest-users at lists.onebuilding.org
Sent: Fri, October 8, 2010 11:55:13 AM
Subject: RE: [Equest-users] design flow input vs. SV-A supply flow reporting

First, thanks to Carol forelevating my understanding of elevation in eQuest  
(see what I did there??? it’s a Friday alright)…  

That was always a mystery to me and I’m finding elevation is indeed the source 
of my CFM’s bumping up (not doubling though) on at least one previous project.

That said, Paul:  

I’m pretty sure you can expect any entered zone-level design airflows (including 
exhaust) to potentially override or otherwise mess with system level airflow 
inputs if/when they ever sum to be larger.  

If you specify a system-level design airflow which is below what the loads 
require but not in conflict with any zonal inputs, eQuest appears to simply 
adjust upwards for elevation if >0, then upward to the limits of your entered 
max-flow-ratio, then follows through and spits back unmet load hours in the 
results, as you’d expect, but importantly will not inflate your system’s design 
CFM beyond the max-flow ratio to compensate for unmet loads – so it may be good 
to know whatever is doubling the specified CFM in your model is probably not 
related to your load inputs.  

Oh yeah, the system sizing ratio (found on the first tab opening any airside 
system) will inflate your airflows too if it’s above 1.0 – better check that.

Sidenote: The fasted way I know of to check resulting airflow results is to be 
aware of the summary tab.  After a calc, highlight a system within (or the 
project at the top of) the component tree under air-side HVAC and click the 
summary tab underneath the toolbars.

~Nick

NICK CATON, E.I.T.
PROJECT ENGINEER
25501 west valley parkway
olathe ks 66061
direct 913 344.0036
fax 913 345.0617
Check out our new web-site @ www.smithboucher.com

From:equest-users-bounces at lists.onebuilding.org 
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Matthew W. 
Higgins
Sent: Friday, October 08, 2010 10:54 AM
To: Paul Diglio; Carol Gardner; cstalberg at naturalintelligence.us
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] design flow input vs. SV-A supply flow reporting

Depending on your system type (VAV) I’ve found that you need to ensure your Min 
and Max flow ratios are set at 1.0 for each system, if appropriate. While the 
system sizing ratio is one thing, flow ratios are another. 

But maybe you’ve tried that already, I don’t know…

Matthew Higgins, ASHRAE-HBDP, LEED-AP
Energy Engineer

Bridgers & Paxton Consulting Engineers, Inc.
4600-C Montgomery Blvd. NE
Albuquerque, NM  87109
505-883-4111
505-888-1436  Fax
mwhiggins at bpce.com 

www.bpce.com

From:equest-users-bounces at lists.onebuilding.org 
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Paul Diglio
Sent: Friday, October 08, 2010 9:06 AM
To: Carol Gardner; cstalberg at naturalintelligence.us
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] design flow input vs. SV-A supply flow reporting

Carol:

I am having the same problem with airflow almost double from what I specified.  
I tried the altitude correction and that did not help.

Does the zone air flow and exhaust rate take preference over the fan flow 
parameters?

Thank you,

Paul Diglio

________________________________

From:Carol Gardner <cmg750 at gmail.com>
To: cstalberg at naturalintelligence.us
Cc: equest-users at lists.onebuilding.org
Sent: Fri, October 8, 2010 9:33:46 AM
Subject: Re: [Equest-users] design flow input vs. SV-A supply flow reporting

Not stupid at all, If you have your altitude set to anything but 0 eQUEST will 
adjust your cfm accordingly. I always go in and set it manually to zero. I think 
it reads what it is off the weather file.

Carol
On Fri, Oct 8, 2010 at 6:54 AM, Christian Stalberg 
<cstalberg at naturalintelligence.us> wrote:
They say no question is a stupid question.

Why is my zone level supply flow cfm reported value in the SV-A report 
higher than my overall design flow (ASSIGNED-FLOW) value? The 
system sizing ratio is set at 1.00 (default).

Thanks in advance.

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-- 
Carol Gardner PE
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