Comparison and evaluation of mega watts proton exchange membrane fuel cell combined heat and power system under different waste heat recovery methods

The proportion of renewable energy has emerged in the global energy structure and a range of clean energy resources and technologies are required for deep decarbonization in the global energy system, especially lowcarbon hydrogen. Motivated by the net zero goal, this work proposed two proton exchange membrane fuel cell combined heat and power (PEMFC-CHP) systems with liquid cooling and phase change heat pump (PCHP) cooling, respectively. It compared its adaptivity with that of liquid cooling in terms of the MW-class thermal demand in different cities in China to provide sufficient energy but at a lower cost. The optimal system and operating conditions for different cities are determined by energy, economic and environmental analyses. The results show that the total efficiency of the PEMFC-CHP system with PCHP cooling is significantly improved at the expense of electricity efficiency compared with conventional liquid cooling. The thermal efficiency has been improved from 48.66% to 53.90% with the expense of the drop of electricity efficiency of 1.96% at the current density of 1A center dot cm(-2). It proves that liquid cooling is more suitable for places whose winter temperature is above zero for it saves cost. While PCHP cooling presents better adaptivity in colder zones (below zero) for it can sufficiently meet the high thermal demand. The PCHP cooling in the extremely cold regions can reduce the cost by 2.47 x 106 $/year.

Automated summary

The proportion of renewable energy is increasing in the global energy structure, requiring a range of clean energy resources and technologies for deep decarbonization. This study proposes two proton exchange membrane fuel cell combined heat and power systems with different cooling methods and compares their adaptability to meet the MW-class thermal demand in different cities in China. The results show that the PEMFC-CHP system with phase change heat pump cooling significantly improves overall efficiency but sacrifices electricity efficiency compared to conventional liquid cooling. Liquid cooling is more suitable for above-zero winter temperatures, while phase change heat pump cooling is more adaptable to colder zones and can reduce costs.