A unified approach for the thermodynamic comparison of heat pump cycles
A unified approach for the thermodynamic comparison of heat pump cycles
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DOI：
10.1038/s44172-023-00112-0
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发表时间：
2023-09
期刊：
影响因子：
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通讯作者：
Zhibin Yu;Zahra Hajabdollahi Ouderji
中科院分区：
文献类型：
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作者：
Zhibin Yu;Zahra Hajabdollahi Ouderji
柔性热泵循环在埃文斯-帕金斯循环中引入了蓄热装置，以回收、储存和再利用来自冷凝器的热的液体制冷剂所携带的部分显热，实现比后者更高的性能系数。在本文中，我们开发了一种统一的方法，即循环叠加，以允许比较的灵活的热泵循环与其他性能增强的循环布局，包括两级循环与中间冷却，过冷，闪蒸气体去除，或它们的组合。我们表明，在理想条件下，灵活的热泵循环是热力学上类似的两级热泵循环与充分的过冷或闪蒸气体去除，但没有中间冷却。从能量回收的角度来看，两级循环同时使用其高级压缩机回收和再利用由热液体制冷剂携带的一些显热，而灵活的热泵循环使用热存储器及时地回收和再利用这种热。然而，在充冷和放冷过程中通过真实的换热器的不可逆热传递将降低柔性热泵循环的益处。所有这些性能增强方法的有效性在很大程度上取决于制冷剂的特性。
The flexible heat pump cycle introduces a heat storage device into the Evans-Perkins cycle to recover, store, and reuse part of the sensible heat carried by the hot liquid refrigerant from the condenser, achieving a higher coefficient of performance than the latter. In this paper, we develop a unified approach, namely cycle superposition to allow comparison of the flexible heat pump cycle with other performance-enhancing cycle layouts including two-stage cycles with intercooling, subcooling, flash gas removal, or their combinations. We show that under ideal conditions, the flexible heat pump cycle is thermodynamically similar to two-stage heat pump cycles with full subcooling or flash gas removal, but no intercooling. From the energy recovery perspective, the two-stage cycles recover and reuse some sensible heat carried by hot liquid refrigerant simultaneously using their high-stage compressor, whereas the flexible heat pump cycle decouples the recovery and reuse of such heat in time using a heat storage. However, the irreversible heat transfer via real heat exchangers during charging and discharging processes will reduce the benefits of the flexible heat pump cycle. The effectiveness of all these performance-enhancing methods strongly depends on the characteristics of refrigerants.