Part-load performance analysis of cogeneration system for engine waste heat recovery

Recovering exhaust waste heat of gas fuel engines is an effective way to improve energy utilization rate. A cogeneration system inclusive of a steam Rankine cycle and an absorption refrigeration cycle is proposed to recover exhaust waste heat of a gas fuel engine. An off-design simulation model is established to analyze part-load performance of the cogeneration system in connection with the characteristics of variable engine load. The results show that the equivalent efficiency of cogeneration system is reduced by 2.14% when the engine load drops from 100% to 40%. Moreover, the improvement of system's total efficiency reduces by only 1.64%. Therefore, the cogeneration system shows excellent part-load adaptability. It should be noted that the absorption refrigeration cycle cannot operate normally under 40% engine load due to the crystallization of H₂O-LiBr solution, which can provide the reference for the practical operation.