Efficient waste heat utilization in high-temperature proton exchange membrane fuel cell bus through integration of lithium bromide absorption refrigeration

Compression-type air-conditioning heat pump systems used in high-temperature proton exchange membrane fuel cell (HT-PEMFC) buses significantly increase the vehicle's hydrogen consumption. This study introduces a lithium bromide (LiBr) absorption refrigeration air-conditioning system into a fuel cell bus, aiming to convert the high-quality waste heat produced by the HT-PEMFC into cooling and heating capabilities for balancing the temperature within the vehicle cabin and recover waste heat. Modeling and co-simulation of the HT-PEMFC, LiBr absorption refrigeration system, vehicle thermal model, and compression-type air-conditioning heat pump system were conducted using MATLAB/Simulink. The simulation results indicate that, compared with the traditional compression-type air-conditioning heat pump system, the LiBr absorption refrigeration system can save 6.13-18.17 % of hydrogen and improve the electrical energy and exergy efficiencies by 3.58-10.74 % and 3.74-11.22 %, respectively, under different driving scenarios. Using the LiBr absorption refrigeration system significantly enhances the vehicle's overall fuel utilization efficiency and driving range.