| The heat transfer characteristics of an existing underground heat exchanger are analyzed to find a more accurate correlation to be used in a heat pump simulation. The heat exchanger is described, a computational grid is generated using boundary-fitted coordinates, and results for heat conduction are presented. A computer code for free convection inside the heat exchanger enclosure, using the Boussinesq approximation and a transient vorticity-stream function formulation, is developed and validated by comparing to experimental data. Heat transfer rate results for three Rayleigh numbers in the physical range of interest are presented as functions of time. Two correlations for the heat transfer rate as a function of the Rayleigh number are proposed. Sample results for temperature distribution are shown in graphical form. |
