[Bldg-sim] eQUEST GSHP Unmet Load Hours

Aulbach, John jaulbach at nexant.com
Thu May 22 10:01:25 PDT 2008


Robby:
 
Try putting in more heat exchanger capacity in the ground. Morning warm-ups are always a "bear" anyway.

________________________________

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Robby Oylear
Sent: Thursday, May 22, 2008 9:36 AM
To: bldg-sim at onebuilding.org
Subject: Re: [Bldg-sim] eQUEST GSHP Unmet Load Hours



I've never used an optimum start schedule before.  I tried inputting the -999 flag in the schedule but without much luck.  It reduced the number of load hours from around 1100 total to 800, but did not eliminate the problem.  So far I've found that increasing max zone entering temperature and increasing the supply cfm lowers the unmet load hours, but I'm afraid of increasing the energy use unnecessarily.  I've got the same building using a different system to meet all of its unmet load hours with similar CFM and btu-h heating/sf.

 

Robby Oylear

Mechanical Engineer

direct: 206.788.4571

cell: 206.354.2721

www.rushingco.com <http://www.rushingco.com> 

________________________________

From: Eric Yang [mailto:Eric.Yang at smithgroup.com] 
Sent: Thursday, May 22, 2008 8:17 AM
To: Robby Oylear; bldg-sim at onebuilding.org
Subject: RE: [Bldg-sim] eQUEST GSHP Unmet Load Hours

 

Maybe you can input or modify optimum start schedule. 

 

Eric Yang 

Mechanical Engineer Group

LEED AP, C.E.M

............................................................ 

 

SmithGroup

1850 K Street NW, Suite 250

Washington, D.C. 20006

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eric.yang at smithgroup.com <mailto:eric.yang at smithgroup.com> 

"One of the Best AEC Firms to Work For <http://www.bdcnetwork.com/article/CA6440632.html> "

Building Design + Construction Magazine, May 2007 

See how we do it. /

www.smithgroup.com <http://www.smithgroup.com/> 

 

________________________________

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Robby Oylear
Sent: Thursday, May 22, 2008 11:13 AM
To: bldg-sim at onebuilding.org
Subject: [Bldg-sim] eQUEST GSHP Unmet Load Hours

 

Hi everyone,

 

I'm trying to model a ground source heat pump system in eQUEST using a Water Loop Heat Pump system attached to a ground source heat exchanger.  The system seems to work fine during occupied hour but it just can't meet morning warm-up loads.  I'm doing a systems energy analysis for our local energy code compliance and there is a mandatory night setback of 55 °F from 70 °F in heating.  During winter months the system doesn't seem to be able to jump from 55 °F to 70 °F space temperature in less than 1-2 hours.  I've double checked the fan schedules and the system is allowed to come on during this time.  

 

Does anyone have any suggestions for getting the system to meet these unmet load hours?  

 

Robby Oylear

Mechanical Engineer

direct: 206.788.4571

cell: 206.354.2721

www.rushingco.com <http://www.rushingco.com> 

 

 

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