[Equest-users] Lochinvar Squire/Knight system

Maria Karpman maria.karpman at karpmanconsulting.net
Wed Dec 5 09:05:42 PST 2012


Rob and Bill,

 

We found that modeling service water heating as process load on the heating
loop produces more accurate result because it accounts for difference in
boiler efficiency during heating versus non-heating season, which is
especially important when modeling existing buildings with old atmospheric
boilers. We calculate temperature rise dT based on entering water
temperature (e.g. 50F) and supply temperature (e.g. 120F), and use it in
conjunction with design flow rate GPM to calculate process load for input in
eQUEST: Load[MMBtu/hr]=GPM*dT*8.33
[Lb/gal]*1[Btu/lb-F]*60[min/hr]/1,000,000. We then assign this load to a
secondary loop, coupling it with DHW schedule (we usually use eQUEST default
for that). For Appendix G projects with combination condensing boilers, I
think it is OK to use stand-alone DHW approximation in eQUEST, and we
typically follow this route for LEED projects.  

 

Maria

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Rob Hudson
Sent: Wednesday, December 05, 2012 10:28 AM
To: Bishop, Bill
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Lochinvar Squire/Knight system

 

Thanks for the quick reply.  The project is more exploratory at this point.
This was very helpful.

 

Thanks again, 

Rob

On Wed, Dec 5, 2012 at 10:25 AM, Bishop, Bill <bbishop at pathfinder-ea.com>
wrote:

Rob,

 

That's usually what I do.

 

You can also specify a process load on the hot water loop that the boiler is
attached to.  The problem I see with this method is that the load does not
get broken out separately as a domestic hot water load on the BEPS/BEPU and
other reports. Also, you can't specify a different entering water
temperature (typically 50F) for the DHW, so you may not get the full benefit
of efficiency from a condensing boiler. These may not be big issues for you
depending on the nature of your project.

 

Regards,

Bill

 

 <mailto:wbishop at pathfinder-ea.com> Senior Energy Engineer 28Jun2012

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Rob Hudson
Sent: Wednesday, December 05, 2012 10:04 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Lochinvar Squire/Knight system

 

Has anyone modeled a Squire/Knight combination system?  The Knight (gas
fired boiler for space heating) is indirectly heating domestic hot water in
the Squire.  It seems a simple work around is to create a separate domestic
hot water heater that has the same characteristics as the boiler.  Anyone
have a different suggestion?

 

Thanks,


 

-- 
Rob Hudson





 

-- 
Rob Hudson

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