[Equest-users] DOAS in baseline

[Nick Caton]

Hi Paul!

 

1.       You could specify the DOAS as part of the systems it’s serving (breaking out the fan energies/ERV components/preconditioning and so forth), then the OA and scheduling specified at the zonal level carries through.

2.       If the DOAS has preconditioning/ERV elements maintaining specific temperature setpoints, then those could be specified at the systems being served.  This may not be technically feasible for every system type.

 

I’ve used both approaches in the past: OA-FROM-SYSTEM using dummy zone(s) and integrating DOAS/ERV into the proposed systems served.  I believe both are viable approaches, with the first benefiting from more nuanced control over system behavior (fans, specifically), and the latter being much easier/simpler to set up and troubleshoot.

 

~Nick

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

Smith & Boucher Engineers

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

www.smithboucher.com 

 

From: Paul Diglio [mailto:paul.diglio at sbcglobal.net] 
Sent: Thursday, January 27, 2011 9:41 AM
To: Nick Caton; Susan F; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] DOAS in baseline

 

Nick:

 

If you do not use the OA From System how will eQuest calculate the CFM required by varying occupancy?  In addition, since the DOAS system might not provide the supply air temperatures required eQuest will not correctly calculate the energy required to condition the OA.

 

Paul Diglio

 

________________________________

From: Nick Caton <ncaton at smithboucher.com>
To: Susan F <modelsenergy at gmail.com>; equest-users at lists.onebuilding.org
Sent: Thu, January 27, 2011 10:21:55 AM
Subject: Re: [Equest-users] DOAS in baseline

Hi Susan!

 

Whether or not a baseline model gets a separate system for a proposed design featuring a DOAS is dependent on a few things, including how you decided to approach modeling the DOAS in the proposed model.

 

-          A clarification first:  Type and quantity of baseline systems is determined first and foremost per Appendix G.3.1.1.  You generally have either one system per floor or one system per zone, depending on the system type.  You never start with “one system per proposed system” except by coincidence.

-          If you use a dummy zone approach (not integrating the DOAS into the proposed systems), and you have one baseline system serving only the dummy zone per G.3.1.1 (or its exceptions), and you have specified the ventilation requirements at that dummy zone (not indirectly from the actual zones - using OA-FROM-SYSTEM for the proposed systems)… then you’ll end up with a distinct baseline system handling the ventilation requirements analogous to the proposed DOAS.  

-          In many/most cases (partially dependant on your preferred strategy for handling DOAS’s in your proposed models), you will not have a dedicated baseline system handling the ventilation air.  That’s okay.

 

~Nick

 



 

NICK CATON, E.I.T.

PROJECT ENGINEER

Smith & Boucher Engineers

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

www.smithboucher.com 

 

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Susan F
Sent: Thursday, January 27, 2011 6:11 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] DOAS in baseline

 

This is not exactly an eQUEST question but y'all have been so helpful in the past so I'm hoping you can help here too.  I'm looking for a little clarification.  It was my understanding if you had a DOAS system that heated and cooled the outside air before delivering it to the floor mechanical room to be combined with return air and further conditioned by the AHU in your Proposed building that this system would NOT be modeled separately in the Baseline.  I cannot find anything in 90.1 that would regulate the DOAS system and I'm not sure how you would model it.  (I understand the dummy zone concept for modeling DOAS but not sure that would apply to the Baseline.)

Should it be separate system in the Baseline and would it be VAV or constant volume?  And if it is a separate system what section of 90.1 would you reference for this?


Thanks in advance.

Nick:

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20110127/dbba4acf/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 1459 bytes
Desc: image001.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20110127/dbba4acf/attachment-0001.jpeg>