不可逆回热布雷顿CCHP装置FTT建模
FTT modeling for irreversible regenerative Brayton CCHP plant

应用有限时间热力学理论和方法(FTT)建立了闭式不可逆回热布雷顿热电冷联产(CCHP)装置模型，导出了装置无量纲可用能率、火用输出率、利润率、第一定律效率和火用效率的解析式。通过数值计算得到了各个性能指标与压比的关系，优化了压比。分析了设计参数对最优性能的影响，发现回热能够显著增大第一定律效率和火用效率；增大压气机和透平效率、压力恢复系数能够增大5个性能指标，但前者使相应压比增大，后者使相应压比减小；增大热电比能够显著增大可用能率和第一定律效率；分别存在最佳的供热温度使5个最优性能指标取得最大值；提高冷库温度能增大可用能率和第一定律效率，但会降低火用输出率、火用效率和利润率。
Finite time thermodynamics (FTT) was applied to establish an irreversible regenerative Brayton combined cooling, heating and power (CCHP) plant model. The analytical formulae of dimensionless usable energy rate, exergy output rate, profit rate, first law efficiency and exergy efficiency were derived. The relationships between the five indicators and the pressure ratio were obtained via numerical calculation, and the pressure ratio was optimized. The influences of design parameters on the optimal performances were analyzed. It is found that regeneration can markedly increase the first law efficiency and exergy efficiency. Both the efficiency increases of compressor and turbine, and the pressure recovery coefficient can increase the five indicators, but the former ones lead to larger pressure ratios and the latter one leads to smaller pressure ratios. The increase in the heat to power ratio can markedly increase the usable energy rate and first law efficiency. There exists five optimal heat supply temperatures, respectively, which make the five optimal indicators reach their maximum. The increase in the cooling temperature can increase the usable energy rate and first law efficiency, but will decrease the exergy output rate, exergy efficiency and profit rate. Through the comparisons among the optimal performance, it is found that a compromise should be made in actual design schemes in order to ensure good thermodynamic performance and economic performance.