The Usability of PV-TEG Hybrid Systems on Space Platforms

Abstract

Most space platforms use solar cells to harvest energy. However, solar cells cannot utilize the full electromagnetic spectrum. They can only convert the UV (ultraviolet)and visible parts of the solar spectrum (200–800 nm). The rest of the spectrum is absorbed as waste heat and degrades the efficiency of the solar cell. On the other hand, hybrid PV-TEG modules can convert much more of the solar energy spectrum. According to recent research, hybrid PV-TEG modules can increase the efficiency of solar cells up to 30%. There are many studies which show that PV - TEG hybrid systems have better performance than single PV and TEG systems [1]–[6]. However, data on the usage of hybrid modules in space is very limited or unavailable. In this study, it is aimed to analyse the usage of hybrid PV-TEG systems as a primary power source on satellites. A PV-TEG stackup has been designed through numerically analysis and optimization. It has been observed that if an insulator material with a very low thermal conductivity is integrated into a thermoelectric module instead of a ceramic (Al 2 O 3 )substrate, the resulting hybrid PV - TEG module becomes more efficient. Through this approach it is possible to improve the efficiency of the solar cells by 21,9% and the efficiency of the overall system by 2,95% through the use of a substrate material having a thermal conductivity of k=0,01 W/mK.