Ground Heat Exchanger (GHE) is the key to the efficiency of a Ground Source Heat Pump (GSHP). However, GHE is not standardized as other parts of the GSHP. It is basically a bunch of tubes that need to be properly sized and burred in the ground. Improperly sized GHE can lead to chocked flow and higher pumping cost or stagnate flow and less heat transfer.

Sizing-Ground-Heat-Exchanger

Sizing methods and data of GHE are mostly scattered in installation manuals and other documentations, such as the International Ground Source Heat Pump Association Installation Guide and other literature. 

I have listed some general steps and references needed to size a Ground Heat Exchanger. I am also considering to build a webpage to facilitate the calculation.  Do you think if such a utility is useful? Do you know if there is already web based software to do this?  What do you wish such a sizing utility to do?  Please commentate here or at my website http://heatexch.com/2013/09/14/sizing-a-ground-heat-exchanger-for-i....

Views: 1103

Reply to This

Replies to This Discussion

Since the ground loop is the biggest cost of having Geo installed it's critical to get this right for quickest payback time vs. a conventional HVAC system. Too small of a loop and you won't get the rated EER from the unit, too big and you overpay for installation costs. Reducing the installed cost (therefore payback time) is key to making geothermal a successful technology.

Does your calculator take into account the thermal mass of the ground?

The geo system may be designed for a peak load of 42,000 BTU/hr, but the average load may be closer to 480,000 BTU over a 24hr period (24,000btu/hr). The ground due to it's high thermal mass may only need to produce the average capacity instead of peak.

Does the calculator consider installed cost?

Installed cost varies wildly depending on site conditions and labor costs. Installing a larger loop might make sense at the time of construction since the digging equipment is already on site for construction of the building. There are no landscape considerations to worry about. Same may hold true on a rural farm where land is plentiful and labor costs may cost substantially less. In an urban area where installation costs are high, it might make more sense to size for cooling load and have backup heat strips pick up the rest on those really cold nights.

RSS

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Simon is now a member of Home Energy Pros
1 hour ago
Rob Madden, Solar Home Broker joined Leslie McDowell, BPI's group
Thumbnail

Building Performance Institute (BPI)

BPI is the nation's premier standards development, quality assurance and credentialing organization…See More
10 hours ago
Rob Madden, Solar Home Broker posted a discussion

Indoor Air Quality Monitors and Meters

I'm considering purchasing the AirAdvice for Homes indoor air quality monitor but it seems to have…See More
11 hours ago
Rob Madden, Solar Home Broker joined Sean Lintow Sr's group
Thumbnail

Best Practices (Residential)

Best Building, Retrofitting, or even Auditing Practices - what are they, what should change, what…See More
11 hours ago
Nate Adams replied to Diane Chojnowski's discussion Poll: How confident do you feel about the future of home performance?
"Matt Golden commented on a parody video "Single Pane" a few months back that the 9 year…"
15 hours ago
tedkidd replied to Diane Chojnowski's discussion Poll: How confident do you feel about the future of home performance?
"Words are jargon until they become common. They become common when they refer to something…"
16 hours ago
Evan Mills replied to Diane Chojnowski's discussion Poll: How confident do you feel about the future of home performance?
"Not too surprising that "home performance" is unfamiliar jargon to the average citizen…"
21 hours ago
Craig McManus added a discussion to the group Job Board
Thursday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service