Finally, the waste heat recovery system of energy efficiency and overall future prospectus for the betterment of thermal management of PEMFC is emphasized.Įvaporative cooling is a promising concept to improve proton exchange membrane fuel cells. Discussion on cold start thermal management of fuel cell electric vehicles was provided. In addition to thermal management strategies, integral challenges associated with each thermal management strategy are identified. Passive cooling methods employing vapour chamber, heat pipes and heat spreaders used were another cooling system for stack power ranges between 5 and 10 kW which have the benefit of reduced parasitic losses. Phase change cooling strategy to attain greater heat removal capacity is broadly employed for stacks greater than 10 kW, which is beneficial in a compact size of the cooling system contrasted to the water cooling system. Cooling using nanofluids enables better cooling efficiency than water while downsizing the size and weight of the system. Air cooling is employed for compact stacks of less than 5 kW and water cooling is favoured for stacks greater than 5 kW.
Entropy consequence and irreversible transport mechanisms of the reactants are the major contributions to heat generation. In general, the operating temperature range of a PEMFC is 60-80☌. The present assessment critically explores the recent developments (predominantly last decade) in thermal management strategies of PEMFCs, which encompasses an in-depth analysis of the thermodynamics, corresponding effects on components of PEMFC and the waste heat recovery system. These are thermal management for electrified propulsion aircraft, ultra-high bypass ratio geared turbofans, and high power airborne military systems environmental control systems power and thermal management systems thermal management on supersonic transport aircraft and novel modelling and simulation processes and tools for thermal management.Įffective thermal management strategy for the polymer electrolyte membrane fuel cell (PEMFC) stack is critical in maintaining the overall stack efficiency and durability. In addition to the discussions on these different elements of thermal management systems, several topics of particular priority in aircraft thermal management research are deliberated upon in detail. The terminal aircraft heat sinks include atmospheric air, fuel, and the aircraft structure. Thermal transport systems comprise cooling loops and thermodynamic cycles, along with their associated components and fluids, which move the heat from the source to the sinks over potentially large distances. Heat acquisition mechanisms are the means by which thermal energy is acquired from the sources. Heat sources include both those from propulsion and airframe systems.
These elements comprise heat sources, heat acquisition mechanisms, thermal transport systems, heat rejection to sinks, and energy conversion and storage.
After introducing relevant factors from the ambient environment, the discussion of the challenges and opportunities is guided by a simple classification of the elements involved in thermal management systems. In this review, these challenges are expounded upon, along with possible solutions and opportunities from the literature. These thermal management challenges are so severe that they are becoming one of the major impediments to improving aircraft performance and efficiency. The increase in the use of composites presents a further issue to address, as these materials are not as effective as metallic materials in transferring waste heat from the aircraft to the surrounding atmosphere. This is due to significant growth in the magnitude of onboard heat loads, but also because of their changing nature, such as the presence of more low-grade, high heat flux heat sources and the inability of some waste heat to be expelled as part of engine exhaust gases. The provision of adequate thermal management is becoming increasingly challenging on both military and civil aircraft.
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