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Acta Geotechnica

, Volume 10, Issue 2, pp 209–218 | Cite as

A comparison of laboratory and in situ methods to determine soil thermal conductivity for energy foundations and other ground heat exchanger applications

  • Jasmine E. LowEmail author
  • Fleur A. Loveridge
  • William Powrie
  • Duncan Nicholson
Research Paper

Abstract

Soil thermal conductivity is an important factor in the design of energy foundations and other ground heat exchanger systems. It can be determined by a field thermal response test, which is both costly and time consuming, but tests a large volume of soil. Alternatively, cheaper and quicker laboratory test methods may be applied to smaller soil samples. This paper investigates two different laboratory methods: the steady-state thermal cell and the transient needle probe. U100 soil samples were taken during the site investigation for a small diameter test pile, for which a thermal response test was later conducted. The thermal conductivities of the samples were measured using the two laboratory methods. The results from the thermal cell and needle probe were significantly different, with the thermal cell consistently giving higher values for thermal conductivity. The main difficulty with the thermal cell was determining the rate of heat flow, as the apparatus experiences significant heat losses. The needle probe was found to have fewer significant sources of error, but tests a smaller soil sample than the thermal cell. However, both laboratory methods gave much lower values of thermal conductivity compared to the in situ thermal response test. Possible reasons for these discrepancies are discussed, including sample size, orientation and disturbance.

Keywords

Energy foundations Ground source heat pumps Needle probe  Thermal cell Thermal conductivity  

Notes

Acknowledgments

The authors would like to thank Harvey Skinner for his help in the design, build and instrumentation of the apparatus. The soil samples were provided by Concept Engineering Consultants Ltd and Arup. The TRT was carried out by GECCO2, with fibre optic temperature and strain monitoring by University of Cambridge. We are also grateful for the site support from Canary Wharf Contractors Ltd and Marton Geotechnical Services Ltd. This work forms part of a larger project funded by EPSRC (ref EP/H0490101/1) and supported by Mott MacDonald Group Ltd, Cementation Skanska Ltd, WJ Groundwater Ltd and Golder Associates.

References

  1. 1.
    Abramowitz M, Stegun IA (1972) Handbook of mathematical functions with formulas, graphs, and mathematical tables. US Government Printing OfficeGoogle Scholar
  2. 2.
    Abu-Hamdeh NH, Reeder RC (2000) Soil thermal conductivity: effects of density, moisture, salt concentration, and organic matter. Soil Sci Soc Am J 64:1285–1290CrossRefGoogle Scholar
  3. 3.
    Alrtimi AA, Rouainia M, Manning DAC (2013) Thermal enhancement of PFA-based grout for geothermal heat exchangers. Appl Therm Eng 54:559–564CrossRefGoogle Scholar
  4. 4.
    ASTM International: D 5334–08 (2008) Standard test method for determination of thermal conductivity of soil and soft rock by thermal needle probe procedure. ASTM International, West ConshohockenGoogle Scholar
  5. 5.
    Austin III, WA (1998) Development of an in situ system for measuring ground thermal properties. Master’s thesis, Oklahoma State UniversityGoogle Scholar
  6. 6.
    Banks D (2008) An introduction to thermogeology: ground source heating and cooling. Blackwell, OxfordCrossRefGoogle Scholar
  7. 7.
    Brigaud F, Vasseur G (1989) Mineralogy, porosity and fluid control on thermal conductivity of sedimentary rocks. Geophys J 98:525–542CrossRefGoogle Scholar
  8. 8.
    Bristow KL, Kluitenberg GJ, Horton R (1994) Measurement of soil thermal properties with a dual-probe heat-pulse technique. Soil Sci Soc Am J 58:1288–1294CrossRefGoogle Scholar
  9. 9.
    British Standards Institution: BS 1377:1990 (1990) Methods of test for soils for civil engineering purposes. BSI, LondonGoogle Scholar
  10. 10.
    Carslaw HS, Jaeger JC (1959) Conduction of heat in solids. Oxford University Press, OxfordGoogle Scholar
  11. 11.
    Clarke BG, Agab A, Nicholson D (2008) Model specification to determine thermal conductivity of soils. Geotech Eng 161:161–168CrossRefGoogle Scholar
  12. 12.
    De Vries DA (1974) Heat and mass transfer in the biosphere: transfer processes in the plant environment. Wiley, New YorkGoogle Scholar
  13. 13.
    European Committee for Standardization: TC 341 WI 00341067.6 (2011) Geotechnical investigation and testing—geothermal testing—determination of thermal conductivity of soil and rock using a borehole heat exchanger. Submitted to the CEN EnquiryGoogle Scholar
  14. 14.
    Farouki O (1981) Thermal properties of soils. Series on rock and soil mechanics series. Trans Tech Publications Limited, GermanyGoogle Scholar
  15. 15.
    Gasparre A (2005) Advanced laboratory characterisation of London Clay. Ph.D. thesis, Imperial College LondonGoogle Scholar
  16. 16.
    Graham J (2006) The 2003 R.M. Hardy lecture: soil parameters for numerical analysis in clay. Can Geotech J 43:187–209CrossRefGoogle Scholar
  17. 17.
    GSHPA (2011) Closed-loop vertical borehole design, installation and materials standardsGoogle Scholar
  18. 18.
    GSHPA (2012) Thermal pile design, installation and materials standardsGoogle Scholar
  19. 19.
    Hukseflux Thermal Sensors: TP02 (2003) Non-steady-state probe for thermal conductivity measurement—manual v0908. Hukseflux Thermal Sensors, DelftGoogle Scholar
  20. 20.
    Hukseflux Thermal Sensors: TP02 (2011) Non-steady-state probe for thermal conductivity measurement. http://www.hukseflux.com/products/thermalConductivity/tp02.html
  21. 21.
    Incropera FP, DeWitt DP, Bergman TL, Lavine AS (2007) Fundamentals of heat and mass transfer, 6th edn. Wiley, LondonGoogle Scholar
  22. 22.
    Institute of Electrical and Electronics Engineers, Inc: IEEE Std 442–1981 (1996) Guide for soil thermal resistivity measurements. IEEE, New YorkGoogle Scholar
  23. 23.
    Javed S, Fahlen P (2011) Thermal response testing of a multiple borehole ground heat exchanger. Int J Low-Carbon Technol 6:141–148CrossRefGoogle Scholar
  24. 24.
    Loveridge F, Powrie W, Nicholson D (2014) Comparison of two different models for pile thermal response test interpretation. Acta Geotechnica 9:367–384Google Scholar
  25. 25.
    Midttømme K, Roaldset E (1998) The effect of grain size on thermal conductivity of quartz sands and silts. Petroleum Geosci 4:165–172CrossRefGoogle Scholar
  26. 26.
    Mitchell JK, Kao TC (1978) Measurement of soil thermal resistivity. J Geotech Eng Div 104:1307–1320Google Scholar
  27. 27.
    Pantelidou H, Simpson B (2007) Geotechnical variation of London clay across central London. Géotechnique 57:101–112CrossRefGoogle Scholar
  28. 28.
    Signorelli S, Bassetti S, Pahud D, Kohl T (2007) Numerical evaluation of thermal response tests. Geothermics 36:141–166CrossRefGoogle Scholar
  29. 29.
    Vaughan PR, Chandler RJ, Apted JP, Maguire WM, Sandroni SS (1993) Sampling disturbance—with particular reference to its effect on stiff clays. In: Predictive soil mechanics: proceedings of the Wroth memorial symposium, pp 685–708Google Scholar
  30. 30.
    Witte HJL (2013) Error analysis of thermal response tests. Energy. doi: 10.1016/j.apenergy.2012.11.060

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Jasmine E. Low
    • 1
    Email author
  • Fleur A. Loveridge
    • 1
  • William Powrie
    • 1
  • Duncan Nicholson
    • 2
  1. 1.Faculty of Engineering and the EnvironmentUniversity of SouthamptonSouthamptonUK
  2. 2.Ove Arup and Partners LimitedLondonUK

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