An Analytical Model for Analyzing Transient Heat Transfer around Geothermal Piles with Time-Dependent Heat Flux
Publication: IFCEE 2021
ABSTRACT
Analytical models available in the literature that predict transient heat flow in soils around ground source heat pump systems (GSHPs) mostly simplify the condition and consider constant heating rate. However, in practical application, inlet fluid temperature (thermal loading) changes with time, and therefore, heat flux along the depth varies over time. Therefore, in this study, we developed an analytical model based on a solid cylindrical source model for analyzing transient heat flow in soils surrounding an energy pile by considering a time-dependent heat flux. Heat conduction equation is solved in two-dimensional axisymmetric condition. A time-dependent heat source term can enhance the previous analytical solution (e.g., a solid cylindrical model) for practical applications. In order to solve the heat transfer equation, Green’s function and imaging methods are utilized. Results indicate that soil thermal response close to an energy pile significantly changes while considering a temporal variation of the heating rate.
Get full access to this article
View all available purchase options and get full access to this chapter.
REFERENCES
Amatya, B. L., Soga, K., Bourne-Webb, P. J., Amis, T., and Laloui, L. 2012. Thermo-mechanical behaviour of energy piles. Géotechnique 62, 503–519.
Brandl, H. 2006. Energy foundations and other thermo-active ground structures. Géotechnique 56 (2), 81–122.
Carslaw, H. S., and Jaeger, J. C. 1959. Conduction of heat in solids. Oxford: Clarendon Press, 1959, 2nd ed.
Cherati, D. Y., and Ghasemi-Fare, O. 2019. Analyzing transient heat and moisture transport surrounding a heat source in unsaturated porous media using the Green’s function. Geothermics 81, 224–234.
Cui, P., Yang, H., and Fang, Z. 2006. Heat transfer analysis of ground heat exchangers with inclined boreholes. Applied Thermal Engineering 26, 1169–1175.
Fisher, D. E., Rees, S. J., Padhmanabhan, S. K., and Murugappan, A. 2006. Implementation and validation of ground-source heat pump system models in an integrated building and system simulation environment. HVAC&R Research 12, 693–710.
Ghasemi-Fare, O., and Basu, P. 2013. A practical heat transfer model for geothermal piles. Energy and Buildings 66, 470–479.
Ghasemi-Fare, O., and Basu, P. 2015. “Thermal operation of geothermal piles installed in sand - a comparative assessment using numerical and physical models”, IFCEE, 1721-1730.
Ghasemi-Fare, O., and Basu, P. 2016. Predictive assessment of heat exchange performance of geothermal piles. Renewable Energy 86, 1178–1196.
Ghasemi-Fare, O., and Basu, P. 2019. “Coupling heat and buoyant fluid flow for thermal performance assessment of geothermal piles,” Computers and Geotechnics, 116, 103211.
Joshaghani, M., Ghasemi-Fare, O., and Ghavami, M. 2018. “Experimental Investigation on the effects of temperature on physical properties of sandy soils.” IFCEE 2018, 675-685.
Ingersoll, L. R., Zabel, O. J., and Ingersoll, A. C. 1954. Heat conduction with engineering, geological, and other applications, London (Thames and Hudson), 3rd Edition.
Lamarche, L. 2011. Analytical g-function for inclined boreholes in ground-source heat pump systems. Geothermics 40, 241–249.
Lamarche, L., and Beauchamp, B. 2007. New solutions for the short-time analysis of geothermal vertical boreholes. International Journal of Heat and Mass Transfer 50, 1408–1419.
Man, Y., Yang, H., Diao, N., Liu, J., and Fang, Z. 2010. A new model and analytical solutions for borehole and pile ground heat exchangers. International Journal of Heat and Mass Transfer 53, 2593–2601.
Selvadurai, A. P. S. 2007. The Analytical Method in Geomechanics. Appl. Mech. 60 (3), 87–106. https://doi.org/10.1115/1.2730845.
Tamizdoust, M. M., and Ghasemi-Fare, O. 2020. “A fully coupled thermo-poro-mechanical finite element analysis to predict the thermal pressurization and thermally induced pore fluid flow in soil media.” Computers and Geotechnics, 117, 103250.
Zeng, H. Y., Diao, N. R., and Fang, Z. H. 2002. A finite line-source model for boreholes in geothermal heat exchangers. Heat Transfer, 31(7), 558–567.
Information & Authors
Information
Published In
IFCEE 2021
Pages: 547 - 556
Copyright
© 2021 American Society of Civil Engineers.
History
Published online: May 6, 2021
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.