TITLE

Analysis and thermal response test for vertical ground heat exchanger with two U-loop configuration

AUTHOR(S)
Chang, Keun Sun; Kim, Min Jun
PUB. DATE
February 2016
SOURCE
International Journal of Energy Research;Feb2016, Vol. 40 Issue 2, p189
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
An in situ thermal response test (TRT) is applied to evaluate the thermal performance of the vertical ground heat exchanger (GHX) with two U-loop configuration. A line source method is used to derive the thermal conductivity and borehole thermal resistance from the measured data. Analyses are made to improve the interpretation of TRT data and to investigate the active area of interest in the borehole. Load tests of the GHX are performed to examine the daily variations of ground and mean fluid temperatures associated with daily intermittent operation of ground source heat pump system. Results show that while the ground thermal conductivity of two U-loop GHX is moderately increased, the borehole thermal resistance is significantly reduced, compared with the single U-loop GHX. Of the borehole thermal resistance components evaluated, the grout thermal resistance is the most governing one in the borehole heat transfer (77% of the total borehole thermal resistance), whereas the convective thermal resistance in the tube is almost negligible (less than 2%). Copyright © 2015 John Wiley & Sons, Ltd.
ACCESSION #
112337371

 

Related Articles

  • Ground source heat pumps: observations from United Kingdom ground thermal response tests. Underwood, CP // Building Services Engineering Research & Technology;May2013, Vol. 34 Issue 2, p123 

    The United Kingdom is experiencing a period of rapid growth in the use of ground source heat pump systems. Most installations in the United Kingdom use vertical ‘borehole’ heat-exchanger arrays, the design of which depends on four parameters: formation thermal conductivity,...

  • A Study on the Calculation Model of Rock Soil Thermal Conductivity in the Design of the Ground Source Heat Pump System. Jin Hongwen; Fang Qingshen // Advanced Materials Research;2014, Issue 889-890, p1347 

    The rock soil thermal conductivity is the most important design parameter for the ground source heat pump system. Based on the equation applied for the heat transfer between the geothermal heat exchanger and its surrounding rock soil, a quasi-three dimensional heat conduction model showing the...

  • In-Situ Testing and Analysis of Thermal Properties of the Ground Formation in Jiangsu, China. Shuai Chen // Advanced Materials Research;2014, Issue 933, p477 

    Ground source heat pump (GSHP) systems exchange heat with the ground, often through a closed-loop, vertical, borehole heat exchanger (BHE). The performance of the BHE depends on the thermal properties of the ground formation, as well as soil or backfill in the borehole. The design and economic...

  • Comparative Heat Transfer Efficiency Study of Coaxial and U-loop Boreholes. Jun Wang // GSTF Journal of Engineering Technology;Apr2014, Vol. 2 Issue 4, p1 

    This paper presents the results of comparative heat transfer efficiency study based on in situ full scale tests conducted on conventional U-loop borehole heat exchangers (BHE) and a coaxial BHE. The results show that the coaxial BHE has considerably higher heat transfer efficiency, while...

  • Experimental performance evaluation of a closed-loop vertical ground source heat pump in the heating mode using energy analysis method. Kara, Yusuf Ali // International Journal of Energy Research;Dec2007, Vol. 31 Issue 15, p1504 

    An experimental study is performed to determine the performance of a ground source heat pump (GSHP) system in the heating mode in the city of Erzurum, Turkey. The GSHP system using R-134a as refrigerant has a single U-tube ground heat exchanger (GHE) made of polyethylene pipe with a 16 mm inside...

  • Required Duration For Borehole Test Validated by Field Data. Liu, Yedi D.; Beier, Richard A. // ASHRAE Transactions;2009, Vol. 115 Issue 2, p782 

    Geothermal heat pumps exchange heat with the ground through the use of ground heat exchangers where the heat transfer rate depends on the thermal conductivity of the surrounding soil. An in-situ test is often performed on a vertical borehole to estimate soil thermal conductivity, but the test...

  • A Study of Geothermal Heat Pump and Standing Column Well Performance. Rees, Simon J.; Spitler, Jeffrey D.; Deng, Zheng; Orio, Carl D.; Johnson, Carl N. // ASHRAE Transactions;2004, Vol. 110 Issue 1, p3 

    Standing column wells can be used as highly efficient ground heat exchangers in geothermal heat pump systems, where hydrological and geological conditions are suitable. A numerical model of groundwater flow and heat transfer in and around standing column wells has been developed. This model has...

  • Introduction of a Thermal Response Test (TRT) Apparatus Used for Measuring Underground Heat Exchanger Characteristics. Yi LIU; Yang SHI; Ya-ning ZHANG // Advanced Materials Research;2014, Issue 937, p381 

    A thermal response test (TRT) apparatus is introduced in this paper for determination of the performance of underground heat exchanger in ground-source heat pump system. The inlet and outlet temperatures of the underground heat exchanger can be real-time tested to obtain the heat transfer data....

  • Ground source heat pump system operation under initial ground temperature influence. Zishu Qi; Qing Gao; Yan Liu; Li Bai // Applied Mechanics & Materials;2014, Issue 651-653, p1442 

    Renewable energy is the inevitable choice for the future sustainable energy development. The heat pump system by using earth energy is increasing very rapidly. In this paper, by studying the underground heat exchanger heat transfer mode, the computing platform for GSHP system was established....

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics