[Bldg-sim] geothermal heat pump design

[Keith Swartz]

Abaza,

Since Georgia is predominantly a cooling climate, one approach you could take is to size the geothermal loop for the heating demand and provide a cooling tower to provide cooling beyond what the geothermal loop can do. This will keep the loop installation costs down.

Geothermal systems work best for buildings that have similar amount of cooling and heating each year. If there is more of one than the other, the ground temperature may gradually warm up or cool off over time. The hybrid approach avoids this by sizing the loop for the smaller load (heating or cooling), then if more cooling is needed install a cooling tower and if more heating is needed install a boiler. The controls need to be designed carefully so that the boiler does not heat the ground instead of the building.

Hope this helps.

_____________________

Keith Swartz, P.E., LEED AP
Energy Engineer / Senior Project Manager
Energy Center of Wisconsin
455 Science Drive, Suite 200
Madison, WI 53711
Phone: 608.238.8276 x123
Fax: 608.238.0523
Email: kswartz at ecw.org
Web: www.ecw.org

Energy Center University
Your gateway to sustainable design training and online education programs.
www.ecw.org/university/

-----Original Message-----
From: Abaza Hussein [mailto:ahussein at spsu.edu] 
Sent: Friday, July 24, 2009 11:16 PM
To: David Reddy; 'Nick Caton'; bldg-sim at lists.onebuilding.org
Cc: equest-users at lists.onebuilding.org
Subject: [Bldg-sim] geothermal heat pump design

Designers;
Did any one designed/studied geothermal heat pump for apatment buildings. We have 52 units elderly housing project and investigate using geothermal heat pump. Georgia, USA, requires closed loop wells. Did any one design such system, and is there a better way than drilling so many wells to serve approximatelly 60 heat pumps ( a total of approximatelly 90 tons). 
I appreciate any advice.
H. Abaza