Energy and exergy analyses of pulse combustor integration in air bottoming cycle power plants

Abstract

Air bottoming cycle (ABC) is a recently recommended waste heat recovery bottoming cycle which can be implemented for small scale power plants. Nonetheless, ABC’s low efficiency is preventing the commercialization of this novel idea. One of the possible modifications is the integration of a pulse combustor in order to improve the ABC’s efficiency. In this paper, integration of pulse combustor in ABC configuration is suggested. For pulse combustor implementation in ABC, two different configurations are proposed comprising pulse combustor integration instead of the topping cycle combustion chamber and as a supplementary firing in the bottoming cycle. Energy analysis is conducted by investigating different design variables’ effects on both thermal efficiency and net specific work output. Furthermore, exergy analysis is accomplished by pinpointing the sources of irreversibility within the configurations. Moreover, thermodynamic optimization is performed to identify the maximum power enhancement due to the implementation of the pulse combustion. Integration of the pulse combustor in the topping cycle can increase the thermal efficiency to 50.8% whereas maximum possible ABC’s efficiency is 43.6%. Additionally, pulse combustor implementation as the supplementary firing in the bottoming cycle led to the maximum efficiency of 41.8%.