Ravita Lamba

Parametric Optimization of Concentrated Photovoltaic-Thermoelectric Hybrid System

The current cutting edge in photovoltaic technology states that the conversion efficiency of photovoltaic (PV) systems has inverse relation and thermoelectric systems has direct relation with temperature. Therefore, cascading of thermoelectric (TE) systems with concentrated photovoltaic (CPV) systems has the potential to improve the total power output of CPV system by effectively utilizing the solar spectrum. The excess thermal energy of the PV system can be utilized as heat input in thermoelectric system to generate power. In this chapter, a thermodynamic model based on the first and second laws of thermodynamics for concentrated photovoltaic-thermoelectric (CPV-TE) hybrid system has been developed and analysed in a MATLAB Simulink environment. Further, the parametric optimization has been carried out to improve the overall performance of the hybrid system. The effect of concentration ratio, resistance ratio, thermal resistance between the TE module and the environment and the thermal resistance between the PV and TE modules has been discussed.

Energy and exergy analysis of an irreversible thermionic generator

A new thermodynamic model of an irreversible thermionic generator (TIG) is proposed in which internal as well as external heat losses of the system have been considered. The operating temperatures of cathode and anode have been determined by writing energy balance equations for both electrodes. The expressions for power output, irreversibility, entropy generation, energy and exergy efficiency have been derived analytically. The effect of anode work function and output voltage on the net current density, power output, energy and exergy efficiency has been discussed. For the given operating conditions, the maximum power output, energy and exergy efficiency have been calculated numerically and the optimally operating range of several important parameters has been determined. The criteria for optimization of both design and performance, which may be helpful for choice of cathode and anode material, has been obtained. The results obtained in this study will be helpful in the designing of a practical irreversible thermionic generator and it will give a better understanding of thermodynamic modeling, irreversibilities and entropy generation in the thermionic generator.