Steady-state heat transfer analysis of arbitrarily coiled buried pipes

The heat transfer from buried pipes of arbitrary shape is investigated. An approximate analytical technique, referred to here as the line source approximation (LSA), is developed and is easily applicable to pipes with complicated geometry. The essence of the method is to replace the pipe with a line source. The accuracy of the technique is verified by testing it against the known analytical result for a straight horizontal pipe. A spirally coiled pipe, sometimes proposed in ground-source heat pump designs, is used to demonstrate the applicability of this technique. The LSA is capable of providing detailed information, such as thermal interference, of the complicated geometry on the heat transfer process. The applicability of this technique is limited to steady-state heat conduction in the soil around the pipe.