Renewable Energy, Vol.161, 1046-1058, 2020
Heat transfer analysis of energy piles with parallel U-Tubes
An energy pile with U-tubes is a special type of ground heat exchanger (GHE) formed by setting U-tubes into a concrete pile during the construction of building foundations. The parallel U-tubes increase heat transfer area, thereby improving energy pile performance. The analytical and numerical heat transfer models of U-tube energy piles are established in this study, considering homogenous and heterogeneous thermal properties of the pile and surrounding soil. Analytical solutions are obtained using the Laplace method and superimposition principle. The solutions of the analytical heat transfer model are verified using the numerical model with finite element method. The results provide a method for designing pile heat exchangers with U-tubes in parallel. (C) 2020 Elsevier Ltd. All rights reserved.