Effect of transient low-grade solar heat on liquid thermogalvanic cells

Thermogalvanic cells have attracted huge attention for the conversion of low-grade waste heat into electricity due to their cost effectiveness. The environment in itself is a rich source of untapped energy such as energy from the sun, geothermal waste heat etc. However, the transient nature of this waste heat makes it a challenge for all-day electricity generation. This paper therefore seeks to investigate the effect of the transient nature of the ultra-low-grade solar energy on liquid thermogalvanic cell. Copper sulphate (CuSO₄) electrolyte and copper electrodes were used. The electrolytes were contained in two pyrex 100-ml glass beaker with corks holding the electrode and a thermocouple in each beaker. A 42 cm long tube containing same electrolyte connected the two as a salt bridge. The electrolyte concentrations were varied from 0.2 to 1.0 M at a temperature difference ranging from 2 to 10 °C. The maximum Seebeck coefficient of 0.698 mV/K was recorded at a concentration of 0.8 M CuSO₄ during heating and 0.798 mV/K at a concentration of 1.0 M during cooling. A maximum power output of 3.99 nWcm^-2 was obtained at a concentration of 0.8 M.