[Equest-users] Ground source heat pump/ cooling tower hybrid

[Anthony Hardman]

You'll have to calculate the heating portion of your hybrid loop separately
since DOE2 doesn't allow this setup.  

 

The easiest way I can think of would be to export the hourly GHEX report,
find the instances where the ground loop temperature dips below your design
setpoint, take the corresponding heating load served by the GHEX for that
hour and then replace that GHEX energy with boiler energy.  Don't forget to
properly account for pumping energy depending on how the loops will operate
as designed.  

 

Notice I said easiest, not the most accurate.  It's important to know how
this method will skew your results.  In this case, you'll artificially be
cooling your ground loop in the winter months (when the boiler is operating)
and pulling that energy back out in the summer cooling months for free.
This could have a significant impact on the annual average efficiency
(artificially inflating) of the heat pumps.  

 

Anthony Hardman, PE

LEED AP BD&C

Building Performance Analyst

 <http://www.greenengineer.com/> THE GREEN ENGINEER, LLP

Sustainable Design Consulting - Energy Modeling - LEED Project Management 

50 Beharrell St

Concord, MA 01742

O: 978/610-2801

C: 720/840-7862

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Dane
Heimerman
Sent: Monday, December 13, 2010 12:24 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Ground source heat pump/ cooling tower hybrid

 

Hi there,

We have a building that is conditioned with water source heat pumps. The
loop is maintained by several ground source wells, and also a closed loop
evaporative cooling tower and a hot water boiler. Does anyone know how to
correctly model this loop? Equest will let you put a boiler and a cooling
tower on a ground loop with the wells, but when you run the simulation it
gives an error that says a boiler cannot be on the loop with the ground
source heat exchanger.

 

Any advice is appreciated.

 

Thanks in advance,

 

--

Dane Heimerman

HVAC Engineer

Michael L. Norris&  Associates, Inc.

270 Walker Dr, Suite 201B

State College, PA 16801

p:814.867.3823

f:814.867.4823

 <mailto:daneh at mlnai.com> daneh at mlnai.com

 

 

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