一种新型跨临界CO2冷电联供系统热力分析

提出一种新型跨临界二氧化碳（trans-critical carbon dioxide，TCO₂）再压缩循环和喷射器制冷循环耦合的冷电联供系统。该系统在输出电能的同时，利用低品位热能驱动喷射器工作输出冷量。以输出电量1 MW为设计目标，对比冷电联供系统和再压缩发电系统的性能，研究联供系统各部件（火用）损和主要热力参数对其性能的影响。结果表明：联供系统利用CO₂余热驱动喷射器输出冷量，循环热效率高于单一再压缩系统；加热器（火用）损所占比例最大，回热器次之；透平进口温度、压力和背压对联供系统工质流量、循环效率、输出功率、加热器功率、压缩机耗功及喷射器制冷量等参数影响较大；而冷凝温度和蒸发温度仅对制冷循环制冷量影响较大。在设定条件下，联供系统的循环热效率和（火用）效率可分别达到46.99%和47.21%。

Thermodynamic Analysis for a Novel Combined Power and Refrigeration Cycle Using Trans-Critical CO2

A novel combined power and refrigeration system coupled with a trans-critical carbon dioxide (TCO₂) recompression cycle and an ejector refrigeration cycle is proposed, which produces power output and refrigeration by utilizing low-grade thermal energy discharged from the CO₂ recompression cycle. The performance of combined cycle was compared with that of recompression cycle, and an exergy and parametric analysis was performed to evaluate the effect of key thermodynamic parameters on the performance of the combined cycle. The results show that because of the utilizing of waste heat from CO₂ which drives the ejector to generate cooling capacity, thermal efficiency of the combined cycle is higher than that of the recompression cycle. The biggest exergy loss occurs in the heater and the heat regenerator came second. It is also shown that the turbine inlet pressure, inlet temperature and back pressure have significant effect on the mass flow rate, turbine power output, power consumption of compressor, refrigeration output and thermal efficiency of the combined cycle. However, the condenser temperature and the evaporator temperature only have remarkable influences on the refrigeration output of the ejector refrigeration cycle. The thermal and exergy efficiency of the combined cycle are severally 46.99% and 47.21% under the given condition.