Assessment of maximum efficiency of a burner with heat recovery

Estimates are obtained the maximum efficiency of a system consisting of a burner with heat recovery connected to an ideal heat engine operating according to the Carnot cycle. The burner serves as a heater of the ideal machine, and the cold side is at the ambient temperature. The combustion products heat the hot wall of the ideal machine and then transfer the heat of the combustible mixture supplied to the combustion chamber. Recovery of the heat of the combustible mixture through a heat-conducting wall of a countercurrent heat exchanger, in which the combustion products and the combustible mixture move toward each other in the channels separated by a heat-conducting partition. An estimate is obtained for the total efficiency of the system, which is determined as the ratio of the useful power of the ideal machine to the chemical energy flux reaching the burner device. It is shown that the total performance of the system can approach the Carnot-cycle efficiency with the maximum possible temperature of the hot side of the ideal machine.