An assessment of sand source heat pump systems

Abstract

Two small scale heat pumps have been built to extract heat from warm dry sand. the earlier unit uses R12B1 as the working fluid and the later one R11. the experimental data demonstrate the possibility of providing sterilized water in remote areas using warm dry sand as a heat source. Unsteady state heat transfer rates were measured using an electrically heated tube installed axially in a cylinder of sand. the results agree closely with those predicted by theory. Heat extraction data also obtained by passing cold water through the ground coil of the heat pump.