- Volume 32 Issue 7
DOI QR Code
Prediction of Ground Thermal Properties from Thermal Response Test
현장 열응답 시험을 통한 지중 열물성 추정
Yoon, Seok;Lee, Seung-Rae;Kim, Young-Sang;Kim, Geon-Young;Kim, Kyungsu
- Received : 2016.04.04
- Accepted : 2016.06.21
- Published : 2016.07.31
The use of geothermal energy has increased for economically and environmentally friendly utilization, and a geothermal heat pump (GSHP) system for space heating and cooling is being used widely. As ground thermal properties such as ground thermal conductivity and ground thermal diffusivity are substantial parameters in the design of geothermal heat pump system, ground thermal conductivity should be obtained from in-situ thermal response test (TRT). This paper presents an experimental study of ground thermal properties of U and 2U type ground heat exchangers (GHEs) measured by TRTs. The U and 2U type GHEs were installed in a partially saturated dredged soil deposit, and TRTs were conducted for 48 hours. A method to derive the thermal diffusivity as well as thermal conductivity was proposed from a non-linear regression analysis. In addition, remolded soil samples from different layers were collected from the field, and soil specimens were reconstructed according to the field ground condition. Then equivalent ground thermal conductivity and ground thermal diffusivity were calculated from the lab test results and they were compared with the in-situ TRT results.
Thermal response test;Ground thermal conductivity;Ground thermal diffusivity;Non-linear regression anlaysis
- Anthony, J. H. (2007), "Probability and Statistics for Engineers and Scientists", Third Edition, THOMSON BROOKS/COLE.
- Beck, M., Bayer, P., and Paly, M. C., Hecht-Mendez J., and Zell, A. (2013), "Geometric Arrangement and Operation Mode Adjustment in Low-enthalpy Geothermal Borehole Fields for Heating", Energy Vol.49, pp.434-443. https://doi.org/10.1016/j.energy.2012.10.060
- Bennet, J., Claesson, J., and Hellstrom, G. (1987), "Multipole Method to Compute the Conductive Heat Flows to and between Pipes in a Composite Cylinder", Notes on Heat Transfer, 1987:3, Lund University, Lund, Sweden.
- Carslaw, H. and Jaeger, J. (1947), "Conduction of Heat in Solids", Oxford, Claremore Press.
- Gaia Geothermal. Ground Loop Design Software, GLD2012.
- Ingersoll, L. R. and Zobel, O.J. (1954), "Heat Conduction with Engineering Geological and other Applications", MC Graw-Hill, New York.
- Jun, L., Xu, Z., Jun, G., and Jie, Y. (2009), "Evaluation of Heat Exchange Rate of GHE in Goethermal Heat Pump Systems", Renewable Energy, Vol.34, pp.2898-2904. https://doi.org/10.1016/j.renene.2009.04.009
- Lee, C. H., Park, M. S., Nguyen, T. B., Shon, B., Choi, J. M., and Choi, H. S. (2012), "Performance Evaluation of Closed-loop Vertical Ground Heat Exchangers by Conducting In-situ Thermal Response Tests", Renewable Energy, Vol.42, pp.77-83. https://doi.org/10.1016/j.renene.2011.09.013
- Lee, I. H. (2014), "Easy Flow Regression Analysis", Hannarae Publishing Corporation.
- Lee, K. (2010), "Study on Thermal Characteristics of Backfill Materials for Horizontal Ground Heat Exchanger", Master thesis, Korea University.
- Lim, H. J., Kong, H. J., Kang, S. J., and Choi, J. H. (2011), "The Effect of the Installation Condition of Ground Loop Heat Exchanger to the Thermal Conductivity and Borehole Resistance", Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 23, No.2, pp.95-102. https://doi.org/10.6110/KJACR.2011.23.2.095
- Min, H. S., Yun, T. S., and Jeong, S. S. (2011), "Effect of Group Spacing of Energy Piles on Thermal Analysis", Journal of the Korean Geotechnical Society, Vol.27, No.8, pp.39-50.
- Pahud, D., Fromentin, A., and Hubbuch, M. (1999), "Heat Exchanger Pile System for Heating and Cooling at Zürich Airport", IEA Heat Pump Centre Newslett, Vol.17, No.1, pp.15-16.
- Park, H. (2011), "Thermal Conductivities of Unsaturated Korean Weathered Granite Soils", Master thesis, KAIST.
- Park, H. K., Lee, S. R., Yoon, S., and Choi, J. C. (2013), "Evaluation of Thermal Response and Performance of PHC Energy Pile: Field Experiments and Numerical Simulation", Applied Energy, Vol.103, pp.12-24. https://doi.org/10.1016/j.apenergy.2012.10.012
- Remund, C. P. (1999), "Borehole Thermal Resistance: Laboratory and Field Studies", ASHARE CH-99-2-1.
- Roque, B. T., Jose N. C., and Daniel, C. F. (2015), "How to Correct the Ambient Temperature Influence on the Thermal Response Test Results", Applied Thermal Engineering, Vol.82, pp.39-47. https://doi.org/10.1016/j.applthermaleng.2015.02.050
- Sohn, B. H., Shin., H. J., and Park, S. K. (2005), "Evaluation of Effective Thermal Conductivity and Thermal Resistance in Ground Heat Exchanger Boreholes", Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol.17, No.8, pp.695-703.
- Yoon, S., Lee, S. R., Kim, Y. T., and Go, G. H. (2015), "Estimation of Saturated Hydraulic Conductivity of Korean Weathered Granite Soils using a Regression Analysis", Geomechanics and Engineering, Vol.9, No.1, pp.101-113. https://doi.org/10.12989/gae.2015.9.1.101
- Yoon, S., Lee, S. R., Kim, M. J., and Go, G. H. (2014), "Evaluation of Thermal Response Test of Energy Pie", Journal of the Korean Geotechnical Society, Vol.30, No.4, pp.93-99.
- Yoon, S., Lee, S. R., Kang, H. B., Go, G. H., Kim, M. J., and Shin, H. S. (2013), "Evaluation of Borehole Thermal Resistance in Ground Heat Exchanger", Journal of the Korean Geotechnical Society, Vol.29, No.10, pp.49-56.
- A Prediction of Specific Heat Capacity for Compacted Bentonite Buffer vol.15, pp.3, 2017, https://doi.org/10.7733/jnfcwt.2017.15.3.199
Supported by : 한국연구재단