Theoretical and experimental study on heat pipe cooled thermoelectric generators with water heating using concentrated solar thermal energy

This paper presents the theoretical analysis and experimental validation on the transient behaviour of a proposed combined solar water heating and thermoelectric power generation system. The proposed system consists of concentrated solar thermal device that provides a high heat flux source for thermoelectric generators. Thermoelectric generators are passively cooled using the heat pipes that are embedded inside a heat spreader block. The heat pipe condenser is immersed in a water tank. The immersed liquid cooling technique offers high heat transfer coefficient for cooling of the thermoelectric generators as well as a way to scavenge the heat through water heating that can be used for domestic or industrial purpose. Theoretical analysis develops the governing equations for the proposed system. Results from a scaled down lab setup are used to validate the theoretical analysis. For a flux of 50,000 W/m2 a temperature difference of 75 °C across the thermoelectric generator can be achieved and the hot water can be heated up to 80 °C which can be used for domestic or industrial applications. With 75 °C temperature difference across the TEG hot and cold side, an open circuit voltage of 3.02 V can be generated for each thermoelectric generator with dimensions of 40 mm × 40 mm.