Upper Bounds for the Conversion Efficiency of Diluted Blackbody Radiation Energy into Work

Abstract

Abstract A new formula has been proposed for the Landsberg–Tonge function \chi (\varepsilon ) entering the entropy density flux of the diluted blackbody radiation of dilution factor ε. Two models have been proposed for the conversion of diluted blackbody radiation energy into work. The Carnot and Petela–Landsberg–Press relationships do not provide accurate upper bounds for the real conversion efficiency and in some cases they wrongly estimate positive output work when the converter of radiation energy into work does not operate. Four upper bounds for the conversion efficiency have been derived. The most accurate upper bound efficiency requires the numerical solution of an algebraic equation for the optimum absorber temperature while the second best upper bound efficiency has the advantage that it is a simple analytical formula.