Numerical and Finite Element Analysis of Heat Transfer in a Closed Loop Geothermal System

Abstract

Analysis of the thermal regime created by a geothermal borehole heat exchanger is performed using a closed form radial heat flow equation, a geothermal borehole heat exchanger design tool and a finite element model. Climatic, heat exchanger construction and building load data are entered into the heat exchanger design tool in order to create a theoretical model along with thermal parameters from a number of geological formations.Output data from the design tool model are used in conjunction with the closed form radial heat flow equation to calculate the predicted temperature with respect to time and distance from the heat exchanger for the modelled ground formations. The output data from the design tool is also used to create a number of finite element method models against which the predictions calculated using the closed form radial heat flow equation can be Greek letters:

A preliminary study of the effect of groundwater flow on the thermal front created by borehole heat exchangers

“…A summary of the TEMP/W model construction and fundamental mathematical equations controlling the output of the finite element model is outlined in this paper, readers should refer to Hemmingway and Tolooiyan [30] and [31]for further details. Equation 1, where F is the heat flux, λ is the thermal conductivity, T is the temperature and x is distance, shows that heat flow due to conduction is directly dependent on the thermal conductivity of a material and temperature gradient.…”