不可逆中冷回热再热太阳能布雷顿热机系统的分析

摘要

运用热力学第二定律，分析了恒温条件下，不可逆中冷回热再热太阳能布雷顿热机系统的损失和效率。结果表明：系统的效率随聚光比、高／低温侧换热器有效度的提高而增加；相同工作温度下，提高低温侧换热器有效度对系统效率的提高收益更大。在给定低压压缩机压比和高压透平膨胀比时，随着回热器有效度的增大，系统最大效率增加，最佳总压比减小；随着高／低温侧换热器有效度的增大，系统最大效率增加，最佳总压比增大。在给定总压比时，随着回热器、高低温侧换热器有效度的增加，系统最大效率增加，最佳低压压缩机压比和最佳高压透平膨胀比增大。这为系统的优化设计与节能运行提供了理论指导。%An exergy analysis has been carried out for solar-driven irreversible intercooled regenerated reheated Brayton heat en-gine system under constant temperature based on second law of thermodynamics.Analysis shows that exergy efficiency of the system will increase with concentrated ratio and high/low temperature side heat exchanger efficiency improvement.Improving the low temperature side heat exchanger efficiency at the same working temperature raises more profits for exergy efficiency of the system.Given the low pressure compressor pressure ratio and the high pressure turbine expansion ratio,the biggest exergy effi-ciency of the system increases and the best total pressure ratio decreases with the increase of regenerator effectiveness;Along with the rising of the high/low temperature side heat exchanger efficiency,the biggest exergy efficiency of the system increases, and the best total pressure ratio of the system increases.Given a total pressure ratio,as the regenerator and the high/low temper-ature side heat exchanger increase,the biggest exergy efficiency of the system increases,the best low pressure compressor pres-sure ratio and the optimum high pressure turbine expansion ratio increase.This provides theoretical guidance for the optimal de-sign and energy saving operation of the system.