Solar energy harvesting potential of a photovoltaic-thermoelectric cooling and power generation system: Bidirectional modeling and performance optimization

Abstract

In the present work, a comprehensive thermodynamic and exergoeconomic comparison between concentrated photovoltaic-thermoelectric cooling (CPV-TEC) and concentrated photovoltaic-thermoelectric generation (CPV-TEG) systems was introduced and explored, aiming to actively investigate the energy harvesting potential of the photoelectric-thermoelectric cooling and power generation processes. Transitional characteristics of thermoelectric conversion in concentrated photovoltaic-thermoelectric hybrid (CPV-TEH) system have been outlined through multiple evaluation indicators, including output electricity, cell temperature, thermodynamic efficiency, exergy destruction and unit exergy cost under various decision parameters. Furthermore, operating mode and conversion conditions of thermoelectric device in CPV-TEH system have been sensitively identified to obtain the dual action mechanism of cooling and power generation sequentially. Theoretical models have been compared and validated well with former published results. Results indicate that the operating mode of thermoelectric device could be fully converted from TEG to TEC when the operating current is around 0.27 A; the minimum unit exergy costs are respectively found to be 0.263 $/kwh, 0.148 $/kwh and 0.113 $/kwh for CPV-TEG system and 0.266 $/kwh, 0.152 $/kwh and 0.118 $/kwh for CPV-TEC system at CG = 1, 2, and 3 kW/m2. Present research may be helpful for the design and optimization of the CPV-TEH system to harvest the thermal and electric energy from the sunlight, thus enhancing its energy conversion efficiency.