[Equest-users] ERV in Ottawa

David Eldridge dse at grummanbutkus.com
Thu Dec 9 10:12:04 PST 2010


A couple of thoughts -- from your energy end-use breakdown the consumption
in the heating season far outweighs the cooling season, so based on your
particular situation, the extremes seem to be weighed towards heating.



Also your percentage of outside air in the office building is important.  If
the percentage of outside air isn't very high, most of the heating for the
desired MAT comes from the return air.  Try using the variable reporting to
see how much load is on the preheat coil in your baseline case.



Lastly, if your building has major envelope losses, the ERV won't affect the
use of your perimeter heating system if one is present, which may be
carrying a lot of your heating load.



Hope this helps!



David



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*David S. Eldridge, Jr.**, P**.**E**.**, LEED AP BD+C, BEMP, HBDP*

Project Manager



Direct: (847) 316-9224 | Fax: (847) 328-4550

http://www.grummanbutkus.com



*Grumman/Butkus Associates* | 820 Davis Street, Suite 300 | Evanston, IL
60201

Energy Efficiency Consultants and Sustainable Design Engineers

*


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> -----Original Message-----

> From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-

> bounces at lists.onebuilding.org] On Behalf Of Daniel Knapp

> Sent: Thursday, December 09, 2010 11:56 AM

> To: equest-users at lists.onebuilding.org

> Subject: [Equest-users] ERV in Ottawa

>

> Hello,

>

> I've been trying to understand how ERV works because I am finding the

> energy savings to be somewhat less than I had expected.  Ottawa has a very

> cold climate in the winter and a warm, humid climate in the summer and I

> would expect enthalpy wheels to be a very good energy saving strategy.

> Instead, I am finding that in many cases the building uses more energy and

> in the best case scenario (OA exhaust DH, mixed air reset, modulate HX) on

> a VAV system saves only 0.15%.  I have built a simple box model with one

> system in a two-storey office building and tried a number of different

> control strategies (see attached tables for results).  I have tried a VAV

> and a SZ system.  The ERV is able to save marginally more energy in the SZ

> system, but in neither case are the results what I was expecting.

>

> My question is this:  are these results to be taken at face value and

> believed or is there a better way to model ERVs in a Canadian climate?  It

> seems very unlikely to me that ERVs cannot be controlled in such a way as

> to save significant energy in a climate of extremes.  (.inp file attached

> as well).

>

> With thanks and best wishes,

> Dan

>

>

>
> Daniel Knapp, PhD, LEED® AP O+M

> danielk at arborus.ca

>

> Arborus Consulting

> Energy Strategies for the Built Environment www.arborus.ca

> 76 Chamberlain Avenue

> Ottawa, ON, K1S 1V9

> Phone: (613) 234-7178 ext. 113

> Fax: (613) 234-0740

>
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