A comprehensive thermodynamic and exergoeconomic comparison between single- and two-stage thermoelectric cooler and heater

Energy, exergy and exergoeconomic analysis are carried out for single- and two-stage thermoelectric devices which can be used for either heating or cooling implementation. Coefficient of performance, exergetic efficiency and unit cost of heating/cooling power are investigated as the main target of energy, exergy and exergoeconomic analysis, respectively. A comprehensive comparison between single- and two-stage thermoelectric performances has outlined in different values of current and temperature difference between hot and cold sides. An effective range of current is defined for energy (COP > 0.5 × COPmax), exergy (ε > 0.5 × εmax) and exergoeconomic (cC/H < 2 × cC/H,min) analysis. Thermodynamic analysis results reveal that the maximized energy and exergy efficiency of two-stage thermoelectric is higher in comparison to the single-stage thermoelectric for both heating and cooling modes. Also, based on exergoeconomic results, minimum unit cost of single-stage thermoelectric product is less than that of two-stage thermoelectric for all temperature differences and effective range of current is more widespread for the case of single-stage thermoelectric. Obtained results reveal that the minimum unit cost of cooling power for single- and two-stage cooler is 3.967 and 16.22 $/kW h, respectively, for temperature difference of 10 K.