Realistic maximum efficiency of solar energy conversion into work vs exergy efficiency

Abstract

A new formalism is used to evaluate the amount of available work transported by the solar energy flux. The formalism is based on the concept of statistically deformed blackbody radiation. It covers cases when the concept of exergy is not fully relevant. An indicator called work content factor \(\kappa_{U}^+\)  is used to quantify the proportion of available work in the energy flux. Several previous results are particular cases of this general approach. In case of primary work extractors made of materials without energy bandgap (such as metals), the work content factor decreases by increasing the temperature T_c of the primary work extractor. At large values of T_c and smaller values of the solar radiation concentration work cannot be generated in some cases. Primary work extractors based on materials with bandgap energy (such as solar cells) may provide work when blackbody or statistically deformed blackbody solar radiation is unconcentrated. The work content factor of the solar energy flux is higher in the latter case.