Low carbon fuels can be stored as cryogenic liquids in transportation applications. The vehicle's primary energy conversion device exploits the chemical exergy of such fuels. Due to their low temperatures, however, they contain thermomechanical exergy which is almost always wasted by the energy conversion power train. Thermomechanical exergy has two components: one due to temperature and one due to pressure. In cryogens the thermal component is dominant. Recovering the thermomechanical exergy of cryofuels such as LNG or LH, can increase the overall systemic efficiency of vehicle power trains. We define a system which recovers the thermomechanical exergy of a cryogen a CERS (Cryogen Exergy Recovery System). However, a system which synergistically utilizes both the exergy of a cryofuel and the exergy of the waste heat of a chemical exergy utilization process (e.g. fuel cell or heat engine) we call an ECERS (Enhanced Cryogen Exergy Recovery System). This paper presents the conceptual design of an ECERS using the Ballard fuel cell bus as a 'case study'; however, the emphasis of the paper is on the use of these technologies in a broad context.
Recovery of thermomechanical exergy from cryofuels
Rückgewinnung thermomechanischer Exergie aus gekühlten Brennstoffen
International Journal of Hydrogen Energy ; 22 , 4 ; 435-440
1997
6 Seiten, 2 Bilder, 1 Tabelle, 14 Quellen
Article (Journal)
English
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