Thermodynamic performance analysis of a low-temperature absorption refrigeration system in a proton exchange membrane fuel cell refrigerated vehicle

To utilize the waste heat of a proton exchange membrane fuel cell (PEMFC), an absorption refrigeration system (ARS) with a novel low-temperature working pair LiBr- 1-Butyl-3-methylimidazolium Bromide ([BMIM]Br) /C2H5OH is proposed for cooling in the refrigerated vehicle. The thermodynamic performance of the ARS using LiBr-[BMIM]Br/C2H5OH is investigated under various operating conditions and compared with that using the conventional working pair LiBr/H2O. The efficiency performance of the PEMFC refrigerated vehicle using ARS and vapor compression refrigeration system (VCRS) are also studied and compared under different operating conditions. The results show that the ARS achieves the maximum coefficient of performance (COP) of 0.86 and the generation temperature is reduced to 65.45 degrees C with LiBr-[BMIM]Br/C2H5OH a decrease around 15% in comparison to LiBr/H2O. Comprehensive efficiency of the stack coupled with ARS is up to 85% due to recovery its waste heat. Under identical output power and cooling capacity of the refrigerator vehicle, the stack coupled with a VCRS has a comprehensive efficiency of 70% and requires a larger power scale. Thus, the stack coupled with ARS using LiBr-[BMIM]Br/C2H5OH has a great significance for enhancing the performance, enlarging the mileage, and reducing the cost of the refrigerator vehicle.