Performance assessment of an advanced triple-cycle system based upon solid oxide fuel cells, vacuum thermionic generators and absorption refrigerators

•An advanced triple-cycle system is proposed for waste heat recovery.•Various irreversible losses within the system are mathematically described.•Maximum power density and its efficiency are increased by 20.3% and 18.4%.•Effects of some important parameters on system performance are revealed.•Effects of microstructure parameters and operating conditions are discussed.