A new system for converting combustion heat into electric power was proposed on the basis of reciprocating-flow super-adiabatic combustion in a catalytic and thermoelectric porous element. Self-sustaining combustion of an extremely low-calorific gas was successfully; achieved in the element: because a reciprocating flow in the porous element recirculated energy, effectively regenerating combustion gas enthalpy into an enthalpy increase in the low-calorific gas. In the combustion system. a trapezoidal temperature distribution was established along the flow direction, resulting in a steep temperature gradient in the thermoelectric porous element. Numerical simulation showed that 94% of the combustion heat was transferred through the thermoelectric element by conduction. As a result. the total thermal efficiency, which was defined as the ratio of the electric power generated to the combustion heat, attained a value close to the conversion efficiency of the thermoelectric device itself. (C) 2004 Elsevier Ltd. All rights reserved.