Numerical and experimental evaluation on methods for parameter identification of thermal response tests

Abstract

Several parameter identification methods of thermal response test were evaluated through numerical and experimental study. A three-dimensional finite-volume numerical model was established under the assumption that the soil thermal conductivity had been known in the simulation of thermal response test. The thermal response curve was firstly obtained through numerical calculation. Then, the accuracy of the numerical model was verified with measured data obtained through a thermal response test. Based on the numerical and experimental thermal response curves, the thermal conductivity of the soil was calculated by different parameter identification methods. The calculated results were compared with the assumed value and then the accuracy of these methods was evaluated. Furthermore, the effects of test time, variable data quality, borehole radius, initial ground temperature, and heat injection rate were analyzed. The results show that the method based on cylinder-source model has a low precision and the identified thermal conductivity decreases with an increase in borehole radius. For parameter estimation, the measuring accuracy of the initial temperature of the deep ground soil has greater effect on identified thermal conductivity.

Keywords

ground source heat pump / thermal response / parameter identification method / numerical simulation

References

[1] AustinW. A.Development of an in situ system for measuring ground thermal properties [D], 1998, Oklahoma, Oklahoma State University

[2] YuM. Z., PengX. F.. A simplified model for measuring thermal properties of deep ground soil [J]. Experimental Heat Transfer, 2004, 17(2): 119-130

[3] MOGENSEN P. Fluid to duct wall heat transfer in duct system heat storages [C]// Proceedings of International Conference on Subsurface Heat Storage in Theory and Practice. Stockholm, Sweden, 1983: 652–657.

[4] EkllöfC., GehlinS.TED-A mobile equipment for therma1 response test [D], 1996, Sweden, Lulea University of Technology

[5] ZhaoJ., DuanZ.-qiang.. A method for in-situ determining underground thermal properties based on the cylindrical heat source model [J]. Acta Energiae Solaris Sinica, 2006, 27(9): 934-936

[6] XU W. Analysis of the development strategy and engineering application of ground source heat pump [J]. Construction & Design for Project, 2008(1): 12–13.

[7] TaoW.-quan.Numerical heat transfer [M], 2001, Xi’an, Xi’an Jiaotong University Press: 28-129

[8] KohlT., HopkirkR. J.. “FRAC Ture”-A simulation code for forced fluid flow and transport in fractured porous rock [J]. Geothermics, 1995, 24: 345-359

[9] IngersollL. R., PlassH. J.. Theory of the ground pipe heat source for the heat pump [J]. ASHRAE Transactions, 1948, 54(7): 339-348

[10] CarslawH. S., JaegerJ. C.Conduction of heat in solids, 19592nd edOxford, UK, Oxford University Press: 57-84

[11] ZhouY.-s., LeiMing.. Influence factors analysis on in situ test of ground thermal conductivity [J]. Journal of Donghua University, 2009, 35(4): 472-477

[12] KATSURA T, NAGANO K, TAKEDA S. Heat transfer experiment in the ground with ground water advection [C]// Proceedings of 10th Energy Conservation Thermal Energy Storage Conference. Ecostock’ 2006. New Jersey, 2006: 1–27.

[13] RaymondJ., TherrienR., GosselinL., LefebvreR.. Numerical analysis of thermal response tests with a groundwater flow and heat transfer model [J]. Renewable Energy, 2011, 36: 315-324

[14] LamarcheL., BeauchampB.. A new contribution to the finite line-source model for geothermal boreholes [J]. Energy and Buildings, 2007, 39(2): 188-198

[15] BozdagS., TurgutB., PaksoY. H., DikiciD., MazmanM., EvlityaH.. Ground water level influence on thermal response test in Adana, Turkey [J]. International Journal of Energy Research, 2008, 32(7): 629-633

[16] SignorelliS., BassrttiS., PahudD., KohlT.. Numerical evaluation of thermal response tests [J]. Geothermics, 2007, 36: 141-166

[17] ASHRAE.ASHRAE handbook on HVAC applications [M], 2007, Atlanta, American Society of Heating, Refrigerating and Air-conditioning Engineers, Inc

[18] IgshpaClosed-Loop/Geothermal heat pump systems-design and installation standards (2007 Edition) [M], 2007, USA, Oklahoma State University: 1-28

[19] SharqawyM. H., MokheimerE. M., HabibM. A., BadrH. M., SaidS. A., Al-ShayeaN. A.. Energy, exergy and uncertainty analyses of the thermal response test for a ground heat exchanger [J]. International Journal of Energy Research, 2009, 33(6): 582-592

[20] MarcotteD., PasquierP.. On the estimation of thermal resistance in borehole thermal conductivity test [J]. Renewable Energy, 2008, 33: 2407-2415

[21] Bozda-gS., TurgutB., PaksoyH., DikiciD., MazmanM., EvliyaH.. Ground water level influence on thermal response test in Adana, Turkey [J]. International Journal of Energy Research, 2008, 32(7): 629-633

[22] FujiiH., OkuboH., NishiK., ItoiR., OhyamaK., ShibataK.. An improved thermal response test for U-tube ground heat exchanger based on optical fiber thermometers [J]. Geothermics, 2009, 38: 399-406

[23] FloridesG., KalogirouS.. First in situ determination of the thermal performance of a U pipe borehole heat exchanger, in Cyprus [J]. Applied Thermal Engineering, 2008, 28(2/3): 157-163