[Equest-users] Equest-users Digest, Vol 15, Issue 17

[Min-Hwan Yang]

I think the capacities of boiler is sized based on non-coincident condition as default.

Min-Hwan Yang, LEED AP
Mechanical Engineer | yangm at kjww.com

200 West Jackson Boulevard, Suite 1200 | Chicago, Illinois 60606
312-294-0501 | Direct: 312-356-3750 | Fax: 312-294-0003
www.kjww.com


I have had the same problem when I let EQUEST automatically size the boiler for me.  In my situation, EQUEST drastically oversized the boiler so it was running at 10% capacity 90% of the time.  You can check to see if you have the same problem by looking at report PS-C to see what part load range your boiler is operating at.  To fix the problem, first I manually set the capacity of the boiler, which helped a lot, but the program was still over estimating the energy consumption.  Then, I created a custom performance curve using actual data for my boiler.  That solved my problem.

From: Josh Doherty [mailto:jdoherty at dcengineering.net] 
Sent: Tuesday, June 16, 2009 10:14 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] High boiler energy use compared to HW loop demand

I have a situation where my boiler energy use (= 950 MBtu) is extremely high compared to the hot water loop demand = 550 MBtu.  The modeled efficiency of the boiler is 80%...which should result in an estimated 690 MBtu of boiler energy use.  Any ideas what could be going on here?  Thanks.

Josh Doherty

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