Thermal performance of shallow solar pond under open cycle continuous flow heating mode for heat extraction

Abstract

The thermal performance of a shallow solar pond (SSP) under an open cycle continuous flow heating mode for heat extraction has been investigated. A serpentine heat exchanger (HE), either welded to the absorber plate or immersed in the pond water, has been used for extracting the heat. Suitable computer programs have been developed based on analytical solutions of the energy balance equations for the various elements of the SSP in the presence of the HE. Numerical calculations have been performed to study the effect of different operational and configurational parameters on the pond performance. In order to improve the pond performance, optimization of the various dimensions of the pond with the HE has been performed. The effects of the design parameters of the HE’s tube, i.e. length L he , diameter D and mass flow rate m ˙ f of the fluid flowing through the HE, on the pond performance have been investigated. The outlet temperature of the HE’s fluid T fo is found to increase with increase of the HE length L he , and it decreases with increase of the mass flow rate of the HE’s fluid m ˙ f up to typical values for these parameters. Typical values for L he and m ˙ f are found to be 4 m and 0.004 kg/s beyond which the change in T fo becomes insignificant. Experiments have been performed for the pond under different operational conditions with a HE welded to the absorber plate. To validate the proposed mathematical models, comparisons between experimental and theoretical results have been performed. Good agreement has been achieved.