[Equest-users] 90.1-2007 Table 7.8 Water Heater Efficiencies

[Paul Diglio]

Thanks Kushagra & Nick.

Paul Diglio





________________________________
From: Nick Caton <ncaton at smithboucher.com>
To: Kushagra Juneja <kce4 at kamalcogentenergy.com>; Paul Diglio 
<paul.diglio at sbcglobal.net>; equest-users at lists.onebuilding.org
Sent: Wed, October 5, 2011 9:40:19 AM
Subject: RE: [Equest-users] 90.1-2007 Table 7.8 Water Heater Efficiencies

Note: Forwarded message is attached.


I expect the natural followup is “how do I put this (SL) into eQuest?”
 
Attached thread spells out how you start with SL and arrive at UA.  Also 
includes an example with the electric heater equation.
 
~Nick
 
 
NICK CATON, P.E.
SENIOR ENGINEER
 
Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com
 
From:equest-users-bounces at lists.onebuilding.org 
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Kushagra Juneja
Sent: Wednesday, October 05, 2011 12:13 AM
To: 'Paul Diglio'; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] 90.1-2007 Table 7.8 Water Heater Efficiencies
 
Hi Paul,
 
There are two things being talked about, one is thermal efficiency and the other 
is standby loss. Standby loss represented as (Q/800+110 SqRt V) and thermal 
efficiency represented as 80%. I had the same doubt a while back. If you look at 
other Formulae they are represented in the same way. Like for instantaneous 
water heaters Energy Factor is given by 0.62-0.0019V. Btu/h is the unit for 
Standby Loss. Not a multiplication factor. Hope this helps.
 
Cheers
 
Kushagra 
 
 

________________________________

From:equest-users-bounces at lists.onebuilding.org 
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Paul Diglio
Sent: Tuesday, October 04, 2011 5:07 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] 90.1-2007 Table 7.8 Water Heater Efficiencies
 
Could anyone help me understand the calculation for the minimum efficiency of 
gas storage water heaters per the table above?

The calculation is 80%Et (Q/800+110 SqRt V) SL, Btuh.

I understand that Q is the nameplate input rate in Btuh and V is the volume.

Do I use the volume of the whole system, the storage tank only or the recovery 
rate volume?

I understand SL is the standby loss.  Does SL, Btuh mean multiply the equation 
in parenthesis by the standby loss in btu's per hour?

Thanks for the help,

Paul Diglio
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