Thermodynamic and Comparative Analysis of Ejector Refrigeration Cycle and Absorption Refrigeration Cycle Integrated Wet Ethanol-Fueled HCCI Engine for Cogeneration of Power and Cooling

This study attempted for the proposal and analysis of a combined cycle that consists of a wet ethanol-fueled and turbocharged homogeneous charge compression ignition (HCCI) engine coupled to ejector refrigeration cycle (ERC) and absorption refrigeration cycle (ARC) for the simultaneous generation of two distinct outputs, namely, power and refrigeration. Both first and second laws of thermodynamics were employed to develop a thermodynamic model, which has been applied to investigate the performance of combined cycle. Furthermore, performance of the combined cycle for ERC versus ARC was compared and assessed after altering operating parameters (turbocharger pressure ratio, turbocharger compressor efficiency, ambient temperature, and the entrainment ratio of ERC and generator temperature of ARC) to study their effect on engine power output, refrigeration load, exergy of refrigeration, and energy and exergy efficiencies of the cooling-power cogeneration cycle. Results show that the elevated pressure of turbocharger results in the enhancement of HCCI engine power and increase of the refrigeration of thermal load, simultaneously. However, the increasing ambient temperature shows the decline of HCCI engine efficiencies and energy efficiency of cogeneration, while the cogeneration cycle exergy efficiency is found increasing. Furthermore, the results are reported for the refrigeration performed by lithium bromide–water (LiBr–H₂O)-operated ARC, and R134a- and R290-operated ERC, respectively. Mapping of exergy destruction for the presented cogeneration cycle discovered HCCI engine, boiler of ERC, generator of ARC, and catalytic convertor as the components of significant exergy destruction. Entrainment ratio and type of refrigerant employed in ERC and the generator temperature of ARC show a marginal impact on the COPs of these cycles.