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

•Proposed a system for concentrated solar thermoelectric power generation.•Proposed system provides a secondary function of water heating.•Heat pipes are used for efficient heat transfer under high heat flux.•Case study for a remote off grid house is presented with brief system sizing. 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 50,000W/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 3.02V can be generated for each thermoelectric generator with dimensions of 40mm×40mm.