Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
권호 표지

Evaluation of Thermal Conductivity for Grout/Soil Formation Using Thermal Response Test and Parameter Estimation Models

열응답 시험과 변수 평가 모델을 이용한 그라우트/토양 혼합층의 열전도도 산정

  • 손병후 (한국건설기술연구원 화재 및 설비 연구부) ;
  • 신현준 (한국건설기술연구원 화재 및 설비 연구부) ;
  • 안형준 ((주) 코오롱건설)
  • Published : 2005.02.01
Download PDF
⟨ Previous Next ⟩

Abstract

The Performance of U-tube ground heat exchanger for geothermal heat Pump systems depends on the thermal properties of the soil, as well as grout or backfill materials in the borehole. In-situ tests provide a means of estimating some of these properties. In this study, in-situ thermal response tests were completed on two vertical boreholes, 130 m deep with 62 mm diameter high density polyethylene U-tubes. The tests were conducted by adding a monitored amount of heat to water over a $17\~18$ hour period for each vertical boreholes. By monitoring the water temperatures entering and exiting the loop and heat load, overall thermal conductivity values of grout/soil formation were determined. Two parameter estimation models for evaluation of thermal response test data were compared when applied on the same temperature response data. One model is based on line-source theory and the other is a numerical one-dimensional finite difference model. The average thermal conductivity deviation between measured data and these models is of the magnitude $1\%$ to $5\%$.

Keywords

References

  1. IGSHPA, 2000, Grouting for Vertical Geothermal Heat Pump Systems: Engineering Design and Field Procedures Manual, International Ground Source Heat Pump Association, Still-water
  2. Mogensen, P., 1983, Fluid to duct wall heat transfer in duct system storages, Proceedings of the International Conference on Subsurface Heat Storage in Theory and Practice. Swedish Council for Building Research, June 6-8
  3. Spilker, E. H., 1998, Ground-coupled heat pump loop design using thermal conductivity testing and the effect of different backfill materials on vertical bore length, ASHRAE Transactions, Vol. 104, pp. 775-779
  4. Smith, M. D. and Perry, R. L., 1999, Borehole grouting: field studies and thermal performance testing, ASHRAE Transactions, Vol. 105, pp. 451-457
  5. Martin, C. A. and Kavanaugh, S. P., 2002, Ground thermal conductivity testing control site analysis, ASHRAE Transactions, Vol. 108, pp. 945-952
  6. Beier, R. A. and Smith, M. D., 2002, Borehole thermal resistance from line-source model of in-situ tests, ASHRAE Transactions, Vol. 108, pp. 212-219
  7. Beier, R. A. and Smith, M. D., 2003, Minimum duration of in-situ tests on vertical boreholes, ASHRAE Transactions, Vol. 109, pp. 475-486
  8. Zhang, Q. and Murphy, W. E., 2000, Measurement of thermal conductivity for three bore-hole fill materials used for GSHP, ASHRAE Transactions, Vol. 106, pp. 434-441
  9. Shonder, J. A. and Beck, J. V., 2000, Field test of a new method for determining soil formation thermal conductivity and borehole resistance, ASHRAE Transactions, Vol. 106, pp. 843-850
  10. Bose, J. E., Smith, M. D., and Spitler, J. D., 2002, Advances in ground source heat pump systems; an international overview, Proceedings of the 7th IEA Heat Pump Conference, Vol. 1, pp. 313-324
  11. Sohn, B. H., Cho, C. S., Shin, H. J., and An, H. J., 2004, Cooling and heating performance evaluation of a ground source heat pump, Proceedings of the KSME 2004 Spring Annual Meeting, pp. 2117-2122
  12. Sohn, B. H., Shin, H. J., and Park, S. K., 2004, Comparative analysis of life-cycle costs of ground source heat pump and conventional HVAC system, Proceedings of the SAREK 2004 Summer Annual Conference, pp. 1339-1344
  13. Ingersoll, L. R. and Plass, H. J., 1948, Theory of the ground pipe heat source for the heat pump, Heating, Piping & Air Conditioning, July, pp. 119-122
  14. Carlslaw, H. S. and Jaeger, J. C., 1947, Conduction of Heat in Solids, Oxford, Claremore Press
  15. Abramowitz, M. and Stegun, I. A., 1964, Handbook of Mathematical Functions, National Bureau of Standards, Applied Mathematics Series 55, US Department of Commerce
  16. Kavanaugh, S. P. and Rafferty, K., 1997, Ground-Source Heat Pumps: Design of Geo-thermal Systems for Commercial and Institutional Buildings, ASHRAE, Atlanta
  17. Remund, C. P., 1999, Borehole thermal resistance: laboratory and field studies, ASHRAE Transactions, Vol. 105, pp. 439-445
  18. Press, W. H., Teukolsky, S. A., Vetterling, W. T. and Flannery, B. P., 1992, Numerical Recipes in Fortran: The Art of Scientific Computing, 2nd ed., Cambridge University Press
  19. Salomone, L. A. and Marlowe, J. I., 1989, Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems: Field Manual, Special Report(EPRI CU-6600), Electric Power Research Institute