A unified concept of hydride heat conversion and low-concentration gaseous waste combustion is suggested and investigated by a numerical simulation method. In accordance with the concept, both the processes are carried out using heat recirculation in a porous medium under the conditions close to thermodynamically perfect ones. A superadiabatic combustion wave serves as a high-temperature source for heat conversion which recovers the equilibrium thermal potential of a hydride pair by heal recirculation from the converter elements, leaving a certain hear conversion stage to the elements entering into the same stage. The concept is discussed using as an example, a system of two porous channels. The problem of increasing the heat effectiveness is solved by reducing irreversible heat losses associated with cyclic temperature alternation of the working medium, a heat converter and its ballast elements. It is shown that the limiting thermal abilities of hydride heat conversion in the refrigeration cycle can be realized almost completely. (C) 1997 International Association for Hydrogen Energy.