Experimental investigation of solar reversible power generation in Thermoelectric Generator (TEG) using thermal energy storage

This paper presents a reliable thermal design for a Thermoelectric Generator (TEG) with a heat sink integrated with Thermal Energy Storage (TES) unit for solar reversible power generation of thermoelectric modules. The heat sink filled with Phase Change Material (PCM) stores thermal energy, which aids in producing continuous solar power generation with extended duration during the night. Thermoelectric Generator (TEG) modules are heated and cooled respectively with the open circuit and closed circuit conditions. The heat rejected by TEG is stored as thermal energy in PCM and this stored thermal energy is utilized as a heat source for power generation during cooling. The experimental setup for cooling comprises of a heat exchanger, which works on the principle of the thermosyphon effect. Thermal and electrical parameters of open-circuit voltage, closed-circuit voltage and electric power output were analyzed for different heat fluxes during heating and cooling. Differential Scanning Calorimeter (DSC) and Thermo Gravimetric Analysis (TGA) tests were conducted for PCM. However, PCM showed a supercooling property in the experimental study at a temperature of 156 °C. In the experimental section, the power generation was almost the same for the heating and cooling cycles at a heat flux of 5.5 kW/m2 - heating cycle produced a net power output of 0.39 W, whereas the cooling cycle produced a net power output of 0.31 W. Thus, experimental investigation signifies that the reversible operation of TEG modules is favourable for day and night cycle operations for solar power generation.