A novel configuration and performance for a two-stage thermoelectric heat pump system driven by a two-stage thermoelectric generator

A new configuration of a combined thermoelectric device, a two-stage thermoelectric heat pump driven by a two-stage thermoelectric generator, is proposed in this article. The thermodynamic model of the combined device is built by using the non-equilibrium thermodynamic theory. The performance characteristics of the new type of thermoelectric system are analysed in detail. Three analytical formulae for the stable working electrical current, the heating load versus the working electrical current, and the coefficient of performance (COP) versus the working electrical current of the combined device are derived. For the fixed total number of thermoelectric elements of the combined device, the allocations of the thermoelectric element pairs among the two thermoelectric generators and the two thermoelectric heat pumps are optimized for maximizing heating load and COP, respectively. The influences of the heat source temperature of the two-stage thermoelectric generator and the heat sink (heating space) temperature of the two-stage thermoelectric heat pump on the optimal performance of the combined thermoelectric device are analysed using detailed numerical examples.