[Equest-users] Cogen heat recovery for dhw
Kimberly.Wiebe at BuroHappold.com
Thu Jul 5 09:39:46 PDT 2012
Thank you for your reply, Edward.
In this configuration the cogen recovered heat is only used for DHW
heating, not space heating. I have the cogen equipment on the DHW loop.
From: Edward Allen [mailto:eallen at long.com]
Sent: Tuesday, July 03, 2012 9:27 PM
To: Kimberly Wiebe; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Cogen heat recovery for dhw
Do you have a seperate DHW loop set up? If so, this is your problem.
Heat recovery from either jacket or exhaust can only go to a single loop
each. If you are proposing to implement cogen then you want to put DHW
loads on the heating loop as a process load with and appropriate
schedule. This way you can assign the heat recovery to a single loop
for simple modeling.
Edward M. Allen, P.E. CEM
Senior Energy Engineer
Investive Building Projects
(formerly LONG Energy Solutions)
----- Reply message -----
From: "Kimberly Wiebe" <Kimberly.Wiebe at BuroHappold.com>
To: "equest-users at lists.onebuilding.org"
<equest-users at lists.onebuilding.org>
Subject: [Equest-users] Cogen heat recovery for dhw
Date: Tue, Jul 3, 2012 4:13 pm
I am working on a project in which the heat recovered from the CHP
equipment (1,416 kBtu/h) is able to meet the entire service water loop
load (1,384.7 kBtu/h). Both the DHW and CHP run 24 hours a day. The
building is both residential and commercial.
Net hourly loop load, including thermal losses and pump heat = Recovered
heat or free cooling heat applied to this loop ... this is true for all
hours in the hourly report.
However, there is still a consistent small natural gas load for the
domestic hot water. It is flat for all hours of the day. What is this
energy use going to? Standby losses?
I am thinking that it is a minimum energy use of the equipment if the
equipment is operating. What is the minimum part load ratio for a gas
fired storage service water heater? Where can I find the inputs/ outputs
to confirm this?
Direct: +1 310 945 4813
kimberly.wiebe at burohappold.com<mailto:kimberly.wiebe at burohappold.com>
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