Comparative exergy analysis of compressed air, liquid nitrogen and classical thermal power cycle for urban vehicles
In the present context of finding ways to decrease CO2 emissions related to transport and energy services,car manufacturers try to develop new zero emissions propulsion technologies.This paper in a first step presents an approach to approximately determine the minimum energy and exergy needed by a vehicle according to some of its intrinsic features(empty weight,Cx,etc.).The implementation and use of the standardized driving cycles UDC(Urban Drive Cycle)and EUDC(Extra-Urban Drive Cycle)allow to have a common basis for the comparison of different concepts of drive-trains.In a second step,an innovative propulsion system for a small urban vehicle is presented.This propulsion concept includes a combination of existing technologies using liquid nitrogen as the main working fluid.The liquid nitrogen is stored in an insulated tank at atmospheric pressure.During engine operation,nitrogen is highly pressurized by a cryopump,then superheated and finally expanded in a para-isothermal process with multistage turbines and reheats.The whole process is operating like an open Rankine cycle.The required heat comes directly or indirectly from the atmosphere that always constitutes the hot source of our system.To increase the efficiency of propulsion and also to prevent an intense formation of frost in the heat exchangers,different ideas are investigated.The best way to achieve these two goals is to add one or more additional closed Rankine cycle operating with a different working fluid such as CO2 or N2O.A comparison between the proposed propulsion system and some proposed on the market is presented in the third part of this paper.
Liquid Nitrogen Car Compressed Air Car Exergy Car Engine Analysis Cryogenic Pumps Cryogenic Heat Exchanger Para-isothermal Expansion
Angel IGLESIAS Daniel FAVRAT
Industrial Energy Systems Laboratory(LENI),(E)cole Polytechnique Fédérale de Lausanne(EPFL)1015 Lausanne,VD,Switzerland
国际会议
桂林
英文
1-14
2013-07-16（万方平台首次上网日期，不代表论文的发表时间）