단순 선형열원 모델을 이용한 지중 유효 열전도도와보어홀 유효 열저항 산정 = Evaluation of Ground Effective Thermal Conductivity andBorehole Effective Thermal Resistance from Simple Line-Source Model

다국어 초록 (Multilingual Abstract)

The design of a ground-source heat pump system includes specifications for a ground loop heat exchanger where the heat transfer rate depends on the effective thermal conductivity of the ground and the effective thermal resistance of the borehole. To evaluate these heat transfer properties, in-situ thermal response tests on four vertical test boreholes with different grouting materials were conducted by adding a monitored amount of heat to circulating water. The line-source method is applied to the temperature rise in an in-situ test and extended to also give an estimate of borehole effective thermal resistance. The effect of increasing thermal conductivity of the grouting materials from 0.818 to 1.104W/m℃ resulted in overall increases in effective thermal conductivity by 15.8 to 56.3% and reductions in effec- tive thermal resistance by 13.0 to 31.1%.

참고문헌 (Reference)

1 손병후, "지중 열교환기 보어홀에서의 유효 열전도도 및 열저항 산정" 대한설비공학회 17 (17): 695-703, 2005

2 손병후, "열응답 시험과 변수 평가 모델을 이용한 그라우트/토양 혼합층의 열전도도 산정" 대한설비공학회 17 (17): 173-182, 2005

3 임효재, "그라우트 재료에 따른 지중 열교환기의 열전도도에 관한 실험적 연구" 대한설비공학회 17 (17): 364-369, 2005

4 Ingersoll, L.R., "Theory of the ground pipe heat source for the heat pump" 119-122, 1948

5 Kline, S.J., "The purpose of uncertainty analysis" 107 : 153-160, 1985

6 Salomone, L.A., "Soil and Rock Classification for the Design of Ground-Coupled Heat Pump Systems： Field Manual" Electric Power Research Institute 1989

7 Beier, R.A., "Minimum duration of in-situ tests on vertical boreholes" 109 : 475-486, 2003

8 Zhang, Q., "Measure- ment of thermal conductivity for three bore- hole fill materials used for GSHP" 106 : 434-441, 2000

9 IGSHPA, "Grouting for Vertical Geothermal Heat Pump Systems：Engineering Design and Field Procedures Manual"

10 Spilker, E.H., "Ground-coupled heat pump loop design using thermal conductivity testing and the effect of different backfill materials on vertical bore length" 104 : 775-779, 1998

11 Martin, C.A., "Ground thermal conductivity testing control site analysis" 108 : 945-952, 2002

12 Gaia Geothermal, "Ground Loop Design Version 2.7 for Windows"

13 Spitler, J.D., "GLHEPRO 3.0 for Windows Users Guide" School of Mechanical and Aerospace Engineering, Oklahoma State University 1999

14 Mogensen, P., "Fluid to duct wall heat transfer in duct system storages" Swedish Council for Building Research 6-8, 1983

15 Shonder, J.A., "Field test of a new method for determining soil formation thermal conductivity and borehole resistance" 106 : 843-850, 2000

16 Carslaw, H.S., "Conduction of Heat in Solids, 2nd ed." Oxford University Press 1947

17 Remund, C.P., "Borehole thermal resistance: laboratory and field studies" 105 : 439-445, 1999

18 Smith, M.D., "Borehole grouting: field studies and thermal performance testing" 105 : 451-457, 1999

19 이세균, "1차원 수치모델과 현지측정에 의한 지중열전도율 및 보어홀 전열저항 해석에 관한 연구" 대한설비공학회 18 (18): 783-790, 2006