Liquid nitrogen fueled, closed Brayton cycle cryogenic heat engine

The use of liquid nitrogen as a combustion free and non-polluting vehicle 'fuel' has recently been demonstrated with the CooLN2Car, a liquid nitrogen powered vehicle. The CooLN2Car's primary limitation is its driving range, which is roughly proportional to the specific energy (energy per unit mass of liquid nitrogen) provided by the open cycle power system employed in the vehicle. In the work reported, a closed Brayton cycle, liquid nitrogen power system is found to be a promising alternative. A thermodynamic analysis indicates that a regenerative closed Brayton cycle system can reach a specific energy that is ten times larger than that for the CooLN2Car open cycle system and four times larger than that for the GM EVI battery power system. In addition, a zero emission vehicle powered by a liquid nitrogen fueled, closed Brayton cycle cryogenic heat engine is projected to have a fuel cost and capital cost commensurate with limited operating parameters (e.g., driving range). (C) 1999 Elsevier Science Ltd. All rights reserved.