Parametric optimum design of an irreversible photon-enhanced thermionic emission solar cell hybrid system

A class of an irreversible thermodynamic model of the hybrid power system consisting of a photon-enhanced thermiomic emission solar cell (PETSC) and a thermoelectric generator (TEG) is established, in which some main irreversible losses existing real hybrid systems are taken into account. Based on equations of the energy balance between the solar cell and thermoelectric generator, expressions for the power output and efficiency of the hybrid system are derived. By using the numerical calculation, influences of the cell area, the energy band gap and electron affinity of the cathode semiconductor materials, and the dimensionless current of the generator on the optimal performance of the hybrid system are analyzed in detail. Under the operating condition of maximum efficiency, the optimal values of some important performance parameters of the hybrid system, such as the energy band gap, electron affinity, area and dimensionless current, are given. The results obtained in this paper show that by using the hybrid system, the solar energy conversion efficiency can be increased by about 10% and the optimal value of the energy band gap for the PESTC of the hybrid system at maximum efficiency is smaller than that of the energy band gap for alone operating PESTC. All the results obtained in this article will provide some theoretical basis for the design and optimal operation of practical PETSC hybrid system.