[Equest-users] Modeling ERV's in Equest

John Forester jforester at dmiinc.com
Thu Jan 7 08:18:23 PST 2010

Here are a couple of other items to check when modeling ERVs in eQuest.


1.	If the system does not have dedicated fans, manually set the
pressure drop across your recovery unit?  The default pressure drops on the
supply and exhaust sides are pretty high.  If there are dedicated fans, make
sure the actual fan power is entered.
2.	Depending on the make-up air temperature control method and system
design, check the capacity control setting.  If the design does not bypass
the recovery section when it is not in use, the parent HVAC fans must
overcome that additional pressure drop during all operating hours.


Also, right clicking on an input field and choosing "Item Help" will provide
a good amount of information as to how eQuest accounts for each input.


Good Luck!  ERVs can be tricky sometimes.


John T. Forester, LEED AP BD+C
Demand Management Institute
35 Walnut Street
Wellesley, MA 02481
Phone: 781 431 1100 x14
Fax: 781 431 1109
email: jforester at dmiinc.com <mailto:jforester at dmiinc.comweb> 
web: www.dmiinc.com <http://www.dmiinc.com/> 


From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Charles
Sent: Thursday, January 07, 2010 10:48 AM
To: Walson, Kristy; 'equest-users at lists.onebuilding.org'
Subject: Re: [Equest-users] Modeling ERV's in Equest


What is the climate like?  If you have a lot of cooling hours where the
outside air temperature is lower than the space temperature it will hurt
your cooling.  For example, if it is 60 outside and your building is calling
for cooling.  With a 74 degree space temperature, if your running your ERV
your actually raising the outside air temp to lets say 65 then cooling it
back down.  One way to help this out is to set your ERV to run "when minimum
outside air" rather than "when fans on".  This will allow the unit to
economize.  You can then continue to play with the controls until you get
the best savings out of it.  If the units cant economize you can also set
the ERV to run based on outside air  delta t's or delta h's.  You can also
set the ERV to put off a particular temperature, such as 55. I believe you
can set both a cooling and a heating temp.   You will then have to choose
the method of either bypassing air or modulating the wheel speed to give you
your specified leaving air temperature.

Hope this helps.


From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Walson,
Sent: Thursday, January 07, 2010 8:15 AM
To: 'equest-users at lists.onebuilding.org'
Subject: [Equest-users] Modeling ERV's in Equest


Hi all,


We are using Equest to model a 500,000 sq ft federal prison facility.  More
than half of the AHU's have energy recovery, so we modeled this at each
applicable unit.  When we run the model with ERV's vs. the model with no
ERV's, it appears as though the ERV's are actually hurting us on the cooling
energy.  Is there a quirk when modeling ERV's in Equest (much like the bug
fix in the Advanced Edit section of VisDOE)?  Does anyone have any
suggestions, or has anyone run into a similar problem before?  


Thanks in advance for the advice...


P.S. Kim - are you happy I'm finally asking a question about Equest??  :)



Kristy M. Walson, PE, LEED AP

Mechanical Engineer / Sustainable Design


TLC Engineering for Architecture
Your Architecture 2030 Partner


255 South Orange Avenue, Suite 1600

Orlando, FL 32801-3463











 <http://www.tlc-engineers.com/> Image removed by sender.

Please consider the environment before printing this email.


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