[BLDG-SIM] eQuest DHW Tank HIR

[David S Eldridge]

For HIR you want the design fuel input and usable heat output, you won't
want to compare it to any measure of efficiency over time.  HIR = 1.67
is more like boiling water in a pot over an open fire.  Keep trying the
manufacturer for a design fuel input rate.  Energy factor is based on
using 64 gallons DHW per day and includes standby losses.
 
http://www.aceee.org/consumerguide/topwater.htm
 
HIR applies to many types of equipment where a storage tank (and losses)
may or may not be part of the system.  As you suggest, the tank losses
can be treated separately.
 
Also, if you make an edit to the HIR, then it will appear in the input
file.  Many items that are left to eQuest defaults will not appear in
the input file unless the default is overridden.
 
Hope this helps!
 
David

 

________________________________

	From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of
tim
	Sent: Wednesday, March 21, 2007 12:52 PM
	To: BLDG-SIM at gard.com
	Subject: [BLDG-SIM] eQuest DHW Tank HIR
	
	
	Utilizng eQuest, under the DHW Equipment tab in wizard mode, the
user can enter the usual characteristics: storage capacity, hot water
usage, supply temp, input rating, etc.
	 
	If you click on the DHW icon under the water-side HVAC tab you
will see a default HIR number under "equipment eficiency" for the tank,
it seems always to be 1.37 (~73% efficiency).  Oddly, this number does
not appear in the input file. though you can change it in Parametric
Runs to examine different DHW efficiencies. Question: 
	 
	-Gas water heaters are typically rated with an EF, and Energy
Factor, essentially an efficiency rating.  However, this number is
usually between .5 and .7, with most being around .6--(This would
translate to an HIR of 1.67).  
	Does anyone know the relationship b/w eQuest's HIR and actual
models EF?  In order to compare different models of water heaters,
should I make this HIR equal to the EF of the current model and then
chane the number for newer more efficent models? Or I wonder if the
manufacturer-rated EF includes standby/tank UA losses and that is why it
is lower than the HIR in eQuest, wh/ is separate from the standby loss
calc. 
	 
	Any thoughts/experience would be great..
	 
	thanks
	tim



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