Thermal performance analysis of borehole size effect on geothermal heat exchanger

作     者：CHOI Hoon-ki YOO Geun-jong LIM Kyung-bin LEE Sang-hoon LEE Chang-hee 

作者机构：Department of Mechanical Design and Manufacturing EngineeringChangwon National UniversityChangwon 641-773Korea Department of Mechanical Design EngineeringHanbat National UniversityDaejon 305-719Korea Department of Energy EngineeringJeonju UniversityJeonju 560-759Korea STX Institute of TechnologyChangwon 642-845Korea 

基　　金：Project financially supported by the Second Stage of Brain Korea 21 Projects and Changwon National University Korea 

出 版 物：《Journal of Central South University》 (中南大学学报（英文版）)

年 卷 期：2012年第19卷第12期

页      码：3524-3529页

摘      要：Thermal performance was the most important factor in the development of borehole heat exchanger utilizing geothermal energy. The thermal performance was affected by many different design parameters, such as configuration type and borehole size of geothermal heat exchanger. These eventually determined the operation and cost efficiency of the geothermal heat exchanger system. The main purpose of this work was to assess the thermal performance of geother^nal heat exchanger with variation of borehole sizes and numbers of U-tubes inside a borehole. For this, a thermal response test rig was established with line-source theory. The thermal response test was performed with in-line variable input heat source. Effective thermal conductivity and thermal resistance were obtained from the measured data. From the measurement, the effective thermal conductivity is found to have similar values for two- pair type （4 U-tubes） and three-pair type （6 U-tubes） borehole heat exchanger systems indicating similar heat transfer ability. Meanwhile, the thermal resistance shows lower value for the three-pair type compared to the two-pair type. Measured data based resistance have lower value compared to computed result from design programs. Overall comparison finds better thermal performance for the three-pair type, however, fluctuating temperature variation indicates complex flow behavior inside the borehole and requires further study on flow characteristics.

主 题 词：large size borehole heat exchanger thermal response test effective thermal conductivity thermal resistance borehole 

学科分类：0820[工学-航空航天类] 082001[082001] 08[工学] 

核心收录：

D　O　I：10.1007/s11771-012-1438-y

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