Effect of a eutectic mixture of D-Mannitol and Magnesium Chloride Hexahydrate on reversible solar thermoelectric power generation: An experimental study

Abstract

• The TEG rejected thermal energy is stored and reused for reverse power generation. • The thermophysical properties of different PCM compositions are analysed. • The electrical performance of TEG incorporating thermal storage is analysed. • The optimized thermal storage composition is 30% MgCl 2 .6H 2 O + 70% D-Mannitol. • The thermosyphon cooling is 4.11 times more effective than natural cooling at 90 W. An experimental analysis of the integration of Magnesium Chloride Hexahydrate mixed with D-Mannitol as the Phase Change Material (PCM) on the colder part of the Thermoelectric Generator (TEG) for day and night power production in solar applications was validated. The heat sink container was filled with different mixtures of PCM to store thermal energy in order to produce a continuous supply of power extended into the night. The experimental arrangement was set for cooling achieved using thermosyphon passive and natural convection. The voltage in open circuit and electrical power were tested for various mixtures and heat inputs while heating and for two types of cooling phases, namely, natural and thermosyphon cooling phases. A 70% D-Mannitol and 30% MgCl 2 .6H 2 O was observed to be the best concentration for all cases of compositions and heat inputs. When cooling using thermosyphon was employed for the TEG cooling system operating with the best concentration subjected to input heat values of 10, 30, 60 and 90 W, the maximum averages of the electrical power output of the TEG were increased to 0.24, 1.26, 1.83 and 1.89 W respectively, with every value being 4.19, 4.17, 4.05 and 4.11 counts greater than the respective measures obtained when cooled naturally.