[BLDG-SIM] equest - select eir & hir questions

David S Eldridge DSE at grummanbutkus.com
Thu Nov 29 11:12:45 PST 2007


Just remember input units divided by same output units and you are set,
for both EIR and HIR.

 

COP and EER (or "typical" units of kW/ton for chillers) are steady state
terms, these would reflect the performance at any point in time, and
correlate to the EIR and HIR model inputs if you are using the equipment
selection point conditions.  Just convert units and take the reciprocal
as necessary.  EIR is the inverse of COP as you mentioned.

 

SEER (and IPLV/NPLV) represent seasonal averages, ideally you will be
calculating this with the model rather than using it as an input.  (It
can be used as a QA check.)  The seasonal performance for your building
probably won't be identical to the conditions used to generate that
weighted equation, so the equipment selection values would be best. 

 

Hopefully you can find a cut sheet for the equipment somewhere to find
the power and capacity values rather than using the SEER.  The
correction equation you referenced is valid under certain conditions -
maybe your project is a match.  I wouldn't use it to select between
different packaged units, but it might be close enough to compare a
packaged unit with a chiller system.  Depends why you are simulating the
project.

 

Hope this helps!

 

David

 

 

 

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Kevin
Kyte
Sent: Thursday, November 29, 2007 9:31 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] equest - select eir & hir questions

 

I need to be schooled in electric input ratio and heat input ratio for
all equipment types: Airside and waterside.

 

Airside - packaged units:  Where does one find a COP for a DX cooling
unit?  I have only seen SEER or EER.  Then I have seen this equation
from archive files, 

Cooling EIR = 0.941 * (1/(SEER/3.413)).  Is this the correct equation?
It was taken from the link:
http://www.gard.com/ml/bldg-sim-archive/msg01626.html.

How about conversion of EER to SEER?  I think I understand HIR = btu
input/btu output?

 

Waterside - chillers:  chiller EIR = 1/ COP, I was also told EIR =
chiller kW *3413 / capacity.  Is this the same, which is correct?

HIR = heat input/ cooling capacity.  Isn't COP the Output / input? So
wouldn't HIR be 1/ COP then.  This is quite confusing and going nowhere
for me, would someone please clarify.

 

Kevin Kyte, LEED AP

Jr. Mechanical Engineer

RobsonWoese, Inc.

T:  716-636-1800

F:  716-636-1856

 

 
 
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