Studies on a two-stage transcritical carbon dioxide heat pump cycle with flash intercooling
Studies on a two-stage transcritical carbon dioxide heat pump cycle with flash intercooling
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DOI：
10.1016/j.applthermaleng.2006.08.008
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发表时间：
2007-02
影响因子：
6.4
通讯作者：
N. Agrawal;S. Bhattacharyya
中科院分区：
文献类型：
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作者：
N. Agrawal;S. Bhattacharyya
对两级闪蒸中冷跨临界二氧化碳热泵循环进行了模拟研究。亚临界和超临界二氧化碳的热力学和输运性质的计算采用一个独家的精度属性代码的基础上最近公布的相关性。结果表明，闪蒸中冷技术是不经济的，与NH3的制冷剂CO2为制冷剂。对于给定的气体冷却器和蒸发器温度，COP显著低于单循环。也没有最佳的级间压力。然而，当级间压力从气体冷却器和蒸发器压力的几何平均值的经典估计降低时，COP出现边际增加。据观察，在中间冷却器中的蒸汽的除湿加热的结合几乎使第二级中的质量流率加倍，这可以归因于在中间冷却器中发生的大闪蒸;这种增加取决于来自第一级的排放温度和蒸发器中的制冷剂流的质量流率。压气机等熵效率对系统性能的影响很小。
Simulation studies on a two-stage flash intercooling transcritical carbon dioxide heat pump cycle are presented. Sub-critical and super-critical thermodynamic and transport properties of carbon dioxide are calculated employing an exclusive precision property code based on recently published correlations. Results exhibit that flash intercooling technique is not economical with CO2refrigerant unlike NH3as the refrigerant. COP is considerably lower than that of the single cycle for a given gas cooler and evaporator temperature. There is no optimum inter-stage pressure as well. However, a marginal increase in COP occurs as inter-stage pressure decreases from the classical estimate of geometric mean of gas cooler and evaporator pressure. It is observed that incorporation of desuperheating of vapour in the intercooler almost doubles the mass flow rate in the second stage which can be attributed to the large flashing that occurs in the intercooler; this increase depends on the discharge temperature from the first stage and mass flow rate of refrigerant flow in the evaporator. Compressor isentropic efficiency shows marginal influence on system performance.