[Equest-users] Equest, heat recovery and separate outside air systems

[Bishop, Bill]

Nick,
 
I know this has been discussed in the forums but I can't find a good
post for you. My understanding is that eQUEST does not model heat
recovery from the zones supplied by an OA-FROM-SYSTEM. The workaround
that I use is to specify heat recovery for each system that receives
ventilation from a DOAS. I calculate the kW/cfm of the DOAS fan(s),
select "Self Contained" for the ERV fans and copy the kW/cfm into the
makeup and exhaust fan fields. (You have to enter it in the "kW" field
first to allow you to enter values in the kW/cfm field, or else use the
"User-Defined Default" option.) If the DOAS has a heating coil, I add
preheat coils to all the systems. One of the problems with this
work-around is that the system fans have to be operating for any hour
that you wish to provide ventilation.
 
Regards,
Bill
 
William Bishop, PE, BEMP, LEED(r) AP | Pathfinder Engineers & Architects
LLP
Mechanical Engineer
 
134 South Fitzhugh Street
Rochester, NY 14608
T: (585) 325-6004 Ext. 114
F: (585) 325-6005
wbishop at pathfinder-ea.com
www.pathfinder-ea.com
P Sustainability - less is more.
________________________________

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of
Mohammad Almasri
Sent: Monday, September 13, 2010 8:58 AM
To: 'Nicholas Lander'; 'equest-users'
Subject: Re: [Equest-users] Equest,heat recovery and separate outside
air systems
 
Dear Nicholas,
 
If you mean that the consumption of the fans will increase when you add
the Heat recovery wheel ; this because of leaving the DP on the default
value (1 in.wg). the default number is very high .
You should either use the actual value or you can set this value as zero
if you included the heat wheel effect on the fan KW/cfm .
 
The eQUEST users archive have a good information about this issue , also
the eQUEST help can provide a good support. 
 
 
 
Regards, 
 
 
 
 
 
 
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of
Nicholas Lander
Sent: Monday, September 13, 2010 3:43 PM
To: equest-users
Subject: [Equest-users] Equest, heat recovery and separate outside air
systems
 
Folks, 

First up, thanks to Bill and David for answering my last question.  
My follow up is this:
 
I'm trying to model a separate outside air system with heat recovery. So
I set it up so all systems take outside air from my OA system (defined
first). But if I then try to add heat recovery to the OA system total
energy (due to cooling and fans) goes up.
 
I'm guessing that a factor in this is that the air goes to all the other
systems but then doesn't come back to the original OA system. (How to
you specify that?) Although, cooling loads should still go down since
exhaust air, whose quantify I specified, is still cooler than outside
air. 
 
So, how do I show any saving with OA heat (or coolth) recovery, which I
know will be huge?
 
thanks in advance.
Nick
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