Field tests for ground thermal properties: methods and impact on ground-source heat pump design.
Author(s) : KAVANAUGH S. P.
Summary
A critical need in the design procedure of closed-loop, ground-source heat pumps (GSHPs) is an accurate knowledge of the thermal properties of soil/rock formations. These properties can be estimated in the field by installing and imposing a thermal load on a ground heat exchanger at the site. Recent developments have improved the capability of predicting thermal properties from the resulting temperature change. An additional benefit is that drilling conditions, determined during the installation of the test heat exchanger, will improve the capability of contractors to estimate project costs. The paper discusses several of the issues and procedures in the development of field tests for thermal property determination. It also addresses the impact of thermal property measurement error upon the resulting ground heat exchanger design, loop operating temperatures, equipment capacity, and system efficiency. A design program that has been evaluated (Thorton et al. 1997) was used to predict results for a 100-ton (351 kW) office building. A 10% variation in thermal conductivity and diffusivity resulted in a 4.5 to 5.8% error in design length, a 1% change in cooling capacity, a 1 °C variation in loop temperature, a 0.7% change in heating capacity, a 2% variation in cooling EER, and no change in heating COP.
Details
- Original title: Field tests for ground thermal properties: methods and impact on ground-source heat pump design.
- Record ID : 2001-1018
- Languages: English
- Source: ASHRAE Transactions. 2000 Winter Meeting, Dallas, Texas + CD-ROM.
- Publication date: 2000
- Document available for consultation in the library of the IIR headquarters only.
Links
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Indexing
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Themes:
Other air-conditioning equipment;
Other heat-pump applications - Keywords: Thermal property; Measurement; Ground-air; Ground; Heat pump
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In situ measurement of ground thermal conductiv...
- Author(s) : WITTE H. J. L., GELDER G. J. van, SPITLER J. D.
- Date : 2002
- Languages : English
- Source: ASHRAE Transactions. 2002 Winter Meeting, Atlantic City, New Jersey. Volume 108, part 1 + CD-ROM.
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Ground thermal conductivity testing: controlled...
- Author(s) : MARTIN C. A., KAVANAUGH S. P.
- Date : 2002/01/12
- Languages : English
- Source: ASHRAE Transactions. 2002 Winter Meeting, Atlantic City, New Jersey. Volume 108, part 1 + CD-ROM.
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Development of an in-situ system and analysis p...
- Author(s) : AUSTIN W. A., YAVUZTURK C., SPITLER J. D.
- Date : 2000
- Languages : English
- Source: ASHRAE Transactions. 2000 Winter Meeting, Dallas, Texas + CD-ROM.
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A model for simulating the performance of a sha...
- Author(s) : CHIASSON A. D., SPITLER J. D., REES S. J., et al.
- Date : 2000/06/24
- Languages : English
- Source: ASHRAE Transactions. 2000 ASHRAE Annual Meeting, Minneapolis, Minnesota + CD-ROM.
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Aquifer thermal energy storage in the Netherlands.
- Date : 2000/09
- Languages : English
- Source: CADDET Energy Effic. Newsl. - suppl. n. 9
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