HEAT EXTRACTION FROM GRADIENT LAYER USING EXTERNAL HEAT EXCHANGERS TO ENHANCE THE OVERALL EFFICIENCY OF SOLAR PONDS

collector and thermal energy storage system. In past heat has been successfully extracted from the Lower Convective Zone (LCZ) from working ponds for industrial process heat applications. Previous theoretical studies have shown that by extracting heat from the NCZ and LCZ together will improve the efficiency of a solar pond to 30% from the present 20% efficiency. This paper discusses concept designs and theoretical predictions of heat extraction from the Non Convective Zone (NCZ) using an external heat exchanger. Here, two methods of heat extraction from different levels within the NCZ using external heat exchanger are presented. A schematic drawing of the first method that uses pumps (forced convection) for heat extraction has been presented. The second method uses thermosyphon effect to transfer the heat from different levels in NCZ to the binary fluid. This paper presents theoretical modeling and experimental results for thermosyphon based heat extraction method. Later theoretical predictions and experimental results have been compared. This investigation shows good prospects for application of this system for heat extraction from NCZ of large solar ponds.