On frequency and temperature dependence of limiting efficiency in direct utilization of quasi-monochromatic radiation

Abstract

The solution to the problem on limiting (thermodynamically permissible) efficiency η_m of direct conversion of energy of quasi-monochromatic radiation into work known from the literature leads to physically unacceptable results (η_m<0) in the range of small frequencies ν and temperatures T _ν of converted radiation. It is shown that the noted feature is a consequence of the approximate character of the mentioned solution obtained without taking into account background heat radiation: the exact solution obtained for η_m is valid for all ν and T _ν ≥ 0 and turns into the solution known earlier for

and hν ≳ kT (where T is the temperature of the surroundings).