A novel distributed energy system using high-temperature proton exchange membrane fuel cell integrated with hybrid-energy heat pump

Abstract

Distributed energy systems based on proton exchange membrane fuel cell (PEMFC) pave a promising technological pathway to achieve carbon neutrality. The waste heat from PEMFC can be well recovered for cooling/heating, but additional systems are required if the available waste heat is not enough to meet the building cooling/heating demands. To achieve a dynamic supply–demand match efficiently and flexibly, this study proposes a novel PEMFC distributed energy system integrated with a hybrid-energy heat pump (HEHP). It can flexibly switch between a single absorption heat pump under sufficient waste heat and a hybrid absorption-compression heat pump under deficient waste heat. The integrated PEMFC-HEHP system is characterized and optimized using a validated model under different working conditions and hybrid configurations. The equivalent power density and fuel cell efficiency can be improved by 18.5% and 7.9% with supply temperatures of −10–10 °C for cooling, and be improved by 54.8% and 20.3% with supply temperatures of 40–60 °C for heating. Optimization yields a maximum equivalent power density of 4.341 kW/m2 in cooling mode and 5.357 kW/m2 in heating mode, compared to 3.290 kW/m2 of the individual PEMFC system. A higher absorption fraction enhances the PEMFC equivalent power while a higher compression fraction improves the HEHP cooling/heating capacity, the hybrid configuration needs to be determined by comprehensively considering the required cooling/heating loads and the available waste heat. The results can facilitate the better development of PEMFC distributed energy systems.