Advances in solar thermoelectric and photovoltaic-thermoelectric hybrid systems for power generation

With the continuously increasing demand for energy, reduction in greenhouse gas emission for daily energy usage is a challenging task. Solar energy based technologies possess the potential to address this challenge since sun is a renewable and abundant source that does not produce any emissions. It would be additional benefit if in the process of using such technologies, wasted heat energy is also converted into electrical energy. Thus, integration of thermoelectric and photovoltaic hybrid systems offers the flexibility to exploit solar spectrum across full wavelength. Thermoelectric Generator (TEG) when integrated with solar electricity conversion technologies result in fabrication of (i) solar thermoelectric generators (STEGs) and (ii) photovoltaic-thermoelectric (PV-TEG) hybrid devices with enhanced efficiency. Improvements in the conversion efficiencies of these technologies would aid in making solar energy at par with conventional forms of energy generation. This paper reviews the prospect of integrating TEG with solar electricity conversion technologies by examining the recent efforts in the field. In particular, the difference in the working of these two type of devices have been focussed on. This review presents in-depth analysis of the state-of-the-art methods used to achieve optimum performance. Moreover, various applications are stated and PV efficiency and losses are discussed along with possible resolutions. Furthermore, recent advancements in these device technologies have been compiled and cost and commercialization aspects have been focussed on. The review aids as a guide to select appropriate procedure of optimizing the performance in these devices as per requirements and specific application.