车辆废热回收有机朗肯循环系统热力性能分析

Thermal Performance of Vehicle Energy-Supplying System Based on Waste Heat Recovery Using Organic Rankine Cycle

基于废热回收有机朗肯循环(organic Rankine cycle, ORC),提出了一套同时回收车辆内燃机冷却废热和烟气废热的车辆供能系统。该系统可通过ORC热转功子系统同时回收汽油机冷却液废热和烟气废热,不仅能够满足车辆不同季节的冷/热需求,而且能够显著改善车辆的整体热功转换效率和燃料节约率。在供暖季,其在节省燃料消耗的同时,也可为车辆供暖;在非制冷供暖季,其在满足车辆所需动力条件下可显著减少燃料消耗;在制冷季,其在节省燃料消耗的同时,不需要增加额外的燃料消耗,也可为车辆空调的运行提供动力。基于天津FAW TOYOTA 8A-FE汽油机车不同工况下的废热数据,针对其构建基于ORC废热回收的车辆供能系统并开展模拟分析。结果表明:降低第一蒸发器对数平均温差跟环境温度及提高车辆速度均能提高透平的输出功率和燃料节约率,基于不同季节的典型操作工况,透平输出功率及燃料节约率的最大值可在冬季获得,最大值分别为11.0 kW和17.2%。该车辆供能系统可有效地利用发动机冷却液废热与烟气废热,ORC热转功子系统的运行不受季节的影响,能够显著减少燃料的消耗,具有节能潜力。

Based on the waste heat recovery using the organic Rankine cycle(ORC), an advanced vehicle energy supply system was proposed to satisfy the different energy demands of vehicles in every season. The proposed system can not only supply enough warm or cool air, but it can also be used to improve the overall vehicle thermal efficiency and fuel saving in different seasons by recovering waste heat from gasoline engine coolant and exhaust gas through the ORC subsystem. In winter the system can supply enough heat to vehicle cabin, while achieving additional net power output. In spring and autumn the system can transfer heat in exhaust gas and coolant into power, saving energy with most significant amount compared with the other seasons. In summer the system supplies the air conditioning subsystem with power, while reducing fuel consumption, and lowering overall energy consumption. Based on the performance data of a Tianjin FAW TOYOTA 8A-FE gasoline vehicle, the energy conservation characteristics of the proposed system was simulated. The results show that reducing the logarithmic mean temperature difference of the first evaporator and environment temperature and enhancing the vehicle speed can increase the turbine power output and fuel saving. The maximum values of the turbine power output and fuel saving rate are obtained in winter, and they are 11.0 kW and 17.2% respectively. The proposed system can remarkably reduce fuel consumption, having potential in energy saving, since it can effectively recover waste heat from engine coolant and exhaust gas, and the operation of the ORC heat transfer power subsystem is not subject to the seasons.