[Equest-users] Groundwater Source Heat Pumps

Anthony Hardman anthony at greenengineer.com
Wed Nov 7 13:56:41 PST 2012

“Entering Water” refers to the condenser loop water temperature as it enters
the condenser (e.g. 59F or 50F).  I believe ISO leaves the delta-T “as
specified by the mfgr.” The older ARI ratings specified this value at 10F
for cooling mode.  You should be able to back it out if you know the heat of
rejection (or extraction) and the condenser flow rate.


Anthony Hardman, PE, LEED AP BD&C

Building Performance Analyst


54 Junction Square Dr

Concord, MA 01742

O: 978/610-2801

C: 720/840-7862


From: Ömer Moltay [mailto:omoltay at mimtarch.com] 
Sent: Wednesday, November 07, 2012 7:09 AM
To: eQUEST Users List
Subject: [Equest-users] Groundwater Source Heat Pumps


Dear All, 

ASHRAE 90.1-2007 minimum EER and COP ratings for heat pumps in Table 6.8.1B.
The referenced testing is ISO 13256-1 and the rating condition is 59F
entering water for cooling and 50F entering water for heating. What is the
exact definition of "entering water"? Shouldn't both entering water and
leaving water temperatures be specified (in other words delta T) for a
meaningful efficiency requirement? 


Ömer Moltay 

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