Reversely-variable circuitry for finned-tube heat exchanger in air source heat pump to enhance its overall energy performance
Reversely-variable circuitry for finned-tube heat exchanger in air source heat pump to enhance its overall energy performance
复制标题
空气源热泵翅片管换热器的反向可变电路，以提高其整体能源性能
DOI：
10.1016/j.ijrefrig.2022.06.021
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发表时间：
2022-06
影响因子：
3.9
通讯作者：
Qu Zhiguo
中科院分区：
文献类型：
--
作者：
Wang Fei;Zhao Rijing;Ma Changming;Huang Dong;Qu Zhiguo
翅片管式换热器(FTHX)作为蒸发器的回路较多，作为冷凝器的回路较少，以便在空气源热泵(ASHP)的供热和制冷运行中都能获得所需的性能。然而，传统的FTHX具有双向固定电路，在相反方向上具有相同的制冷剂流动路径。为使FTHX在蒸发器和冷凝器中灵活发挥不同的流道作用，本文提出了逆变回路。在额定功率为3500 W的室外FTHX中，将原有的4支路分配器先后更换为2支路和3支路分配器，以保留4路蒸发器。然而，在两个分配器之间和气体集管内部增加了两个止回阀，以改变两个回路的流动路径，作为冷凝器合并为一个回路。与双向固定FTHX相比，在额定工况下，与双向固定FTHX相比，在供热性能相近的情况下，反向可变FTHX的制冷量增加5.8%，能效比提高7.2%。进一步的模拟表明，较少的逆变FTHX电路增加了作为冷凝器的总换热系数，主导了FTHX容量的增加和ASHP的整体能量性能。这种新颖的设计为FTHX提供了新的思路，可以推广到不同电路的FTHX。
The finned-tube heat exchanger (FTHX) is preferred to contain more circuits as an evaporator but fewer as a condenser, so as to obtain the desired performance in both heating and cooling operation of the air source heat pump (ASHP). However, the conventional FTHX has two-way fixed circuitry with the same refrigerant flowpath in the opposite direction. In this article, the reversely-variable circuitry is proposed for the FTHX to exhibit different flowpath in evaporator and condenser roles flexibly. The original 4-branch distributor in the outdoor FTHX of a nominal 3500-W ASHP is replaced with a 2-branch one and a 3-branch one successively to maintain 4 circuits as an evaporator. Two check valves, however, are added between the two distributors and inside the gas header to change the flowpath to two circuits merging into one as a condenser. Compared with the two-way fixed FTHX, the reversely-variable one yields 5.8% larger cooling capacity and 7.2% higher EER for the ASHP with similar heating performance under nominal conditions. Further simulation shows that fewer circuits of the reversely-variable FTHX increase the overall heat transfer coefficient as a condenser, dominating the increase in the capacity of the FTHX and the overall energy performance of the ASHP. This novel design provides new thoughts to the FTHXs and can be popularized to those with different circuits.