CO_2套管式气冷器用能效率的热力学第二定律分析

利用1台安装有套管式换热器的跨临界CO_2制冷系统实验台,改变CO_2质量流量、高压侧压力及气冷器冷却水流量,通过实验测得气冷器中CO_2和冷却水沿管长方向的温度分布,并计算气冷器沿管长方向的熵产、火用正文损和火积分布,对气冷器的用能效率进行分析。结果表明,在多种工况下,熵产、火用损和火积耗散均沿管长逐渐降低;熵产和火用损均随CO_2质量流量的增大而降低,而随高压侧压力的升高而增大;质量流量对火积耗散无明显影响。

Energy Consumption Efficiency of a CO2 Tube-in-tube Gas Cooler under Second Law of Thermodynamics

A trans-critical CO2 refrigeration system experimental table equipped with a tube-in-tube gas cooler was utilized to conduct the experiment.The temperature distribution of CO2 and cooling water in the gas cooler was measured under different CO2 mass flow rates, high side pressure and cooling water volume flow rates.The energy consumption efficiency of the gas cooler was analyzed by entropy generation, exergy destruction and entransy dissipation along the tube.Results show that entropy generation, exergy destruction and entransy dissipation decrease along the tube under a variety of conditions.Entropy generation and exergy destruction reduce with the increase of CO2 mass flow rate, and increase with the rise of high side pressure.CO2 mass flow rate has no obvious impact on entransy dissipation.