A Study of the Effect of Borehole Thermal Resistance on the Borehole Length

보어홀 전열저항이 보어홀 길이에 미치는 영향에 관한 연구

  • Published : 2009.10.30

Abstract

The effect of borehole thermal resistance on the borehole length is studied. In performing this work a new concept BLRR(borehole length reduction rate) is developed based on the line source model. The solution of line source model is shown to be valid through the comparison with the data of thermal response test. It is shown that BLRR is a function of soil thermal conductivity(k) and borehole thermal resistance($R_b$). The value of BLRR increases with increasing k, which means reducing $R_b$ is more effective when k is high. The reduction of borehole length with change of $R_b$ is easily estimated with BLRR. The validity of BLRR is also examined with EED analysis.

Keywords

References

  1. 우정선, 김대기, 이세균, 지중열원 열펌프 시스템의 난방성능 해석, 설비공학 논문집, 제16권, 제12호, pp. 1175-1182, 2004
  2. Claesson J. and Eskilson P., Conductive Heat Extraction to a Deep Borehole: Thermal Analysis and Dimensioning Rules, Energy, Vol.13, No.6, pp. 509-527, 1988 https://doi.org/10.1016/0360-5442(88)90005-9
  3. Remund, C. P., Borehole Thermal Resistance : Laboratory and Field Studies, ASHRAE Transactions : SyrIlJ, CH-GG-2-1 pp. 439-445
  4. Kavanaugh ,S. P. and Allan, M. L. Testing of Thermally Enhanced Cement Ground Heat Exchanger Grouts, ASHRAE Transactions : Symposia, CH-99-2-2, pp. 446-450, 1999
  5. Ingersoll, L. R. and Plass, H. J. Theo of the Ground Pipe Heat Source for the Heat Pump ASHVE Transactions, Vol. 47, pp. 119-122, 1948
  6. Carslaw, H. S. and Jaeger, J. C. Conduction of Heat in Solids, 2nd ed., Clarendon Press, Oxford. 1959
  7. 이세균, 김대기, 우정선, 박상일, 1차원 모델에 의한 지중열교환기의 열거동 해석, 한국태양에너지학회논문집, Vol. 25, No.1 ,pp. 97-104. 2005
  8. 이세균, 우정선, 노정근, 김대기, 1차원 수치 모델과 현지측정에 의한 지중열전도율 및 보어홀 전열저항 해석에 관한 연구, 설비공학 논문집, Vol.18, No10, pp. 783-790, 2006
  9. 우정션, 이세균 외, 현지 지중열전도도 측정기술(최종보고서), 지식 경제부, 2008. 5
  10. Hellstrom G. and Sanner B., PC-programs for Borehole Heat Exchanger Design, Asterweg 2, D-35633, Lahnau, Germany, 2000