设计并搭建了柜式空调用微通道蒸发器的性能实验测试平台，测试了微通道蒸发器扁管进出口端温度分布及蒸发器进出口温差、压差、输入功率、制冷量和系统能效比随环境舱温度(18~23℃)升高的变化，并与常规管翅式蒸发器进行了对比。结果表明，微通道蒸发器具有较好的制冷剂流量分配特性，提高了空调出风口温度分布均匀性；由于微通道蒸发器制冷剂充注量低于管翅式蒸发器，且流程也相对缩短，相同工况下，微通道蒸发器进出口压差比管翅式蒸发器降低了33.9%，输入功率降低了4.12%，制冷量提升了2.95%，系统能效比最高提高了6.69%。
With the advantages of high level of integration, high heat exchange efficiency, and low pressure drop penalty in refrigerant side, the refrigerant charge can be reduced effectively in microchannel evaporator, and the size and weight of heat exchanger also can be reduced, therefore the system energy efficiency can be improved effectively. In this work, an experimental system was designed and set up to research the performance of microchannel evaporators. The inlet and outlet temperature distribution of microchannel flat tube were measured. And the variations of inlet and outlet temperature difference, pressure drop, input power, cooling capacity, coefficient of performance with environmental chamber were also analyzed. In addition, the experimental results were compared with conventional finned-tube evaporators under the conditions of ambient chamber temperature in the range from 18 to 23℃. The experiment results indicated that microchannel evaporator had better distribution behavior of refrigerant and can improve the temperature uniformity of air-condition vent. The pressure drops of microchannel evaporator and finned-tube evaporator increased with the increasing of environmental chamber temperature. As the reason that refrigerant charge of microchannel evaporator was lower than finned-tube evaporator and the refrigerant flow path was also shorter than finned-tube evaporator, the maximum pressure drop between two evaporators was 111 kPa under the same temperature. The average pressure drop penalty of microchannel evaporator was reduced by 33.9% compared to the finned-tube evaporator. The compressor power consumption can be reduced by using microchannel evaporator. The system input power of microchannel evaporator was lower than that of finned-tube evaporator and the maximum value was 4.12%. Compared with finned-tube evaporator, the cooling capacity of microchannel evaporator increased by 2.95% and the system coefficient of performance improved by 6.69% under the same temperature of environmental chamber from 18 to 23℃. Based on the above researches, these experimental results can provide data support for application of microchannel evaporator.
[1] Li H, Hrnjak P. Effect of channel geometry on flow reversal in microchannel evaporators [J]. International Journal of Heat & Mass Transfer, 2017, 115: 1-10.
[2] 杨潇寒，付涛涛，姜韶堃，等. 微通道内流体压力降研究进展[J]. 过程工程学报, 2018, 18(04): 680-688.
Yang X H, Fu T T , Jiang S K, et al. Progress in pressure drop of fluid in microchannels [J]. The Chinese Journal of Process Engineering, 2018, 18(04): 680-688.
[3] Kim N H, Kim D Y, Byun H W. Effect of Inlet Configuration on the Refrigerant Distribution in a Parallel Flow Minichannel Heat Exchanger [J]. International Journal of Refrigeration, 2011, 34: 1209-1221.
[4] Tuo H F, Hrnjak P S. Effect of the header pressure drop induced flow maldistribution on the microchannel evaporator performance [J]. International Journal of Refrigeration, 2013, 36(8): 2176-2186
[5] Wang C, Yang K , Tsai J, et al. Characteristics of Flow Distribution in Compact Parallel Flow Heat Exchangers, Part I: Typical Inlet Header [J]. Applied Thermal Engineering, 2011, 31(16): 3226-3234.
[6] Shi J Y, Qu X H, Qi Z G, et al. Investigating Performance of Microchannel Evaporators with Different Manifold Structures [J]. International Journal of Refrigeration, 2011, 34（1）: 292-302.
[7] Wei M, Fan Y L, Luo L G, et al. CFD-based evolutionary algorithm for the realization of target fluid flow distribution among parallel channels [J]. Chemical Engineering Research and Design, 2015, 100: 341-352.
[8] 赵宇，祁照岗，陈江平. 微通道平行流蒸发器流程布置研究与分析 [J]. 制冷学报，2009, 30(1): 25-29．
Zhao Y, Qi Z G, Chen J P. Flow Configuration in Micro-channel Parallel Flow Evaporator [J]. Journal of Refrigeration, 2009, 30(1): 25-29．
[9] Ahmad M, Berthoud G, Mercier P. General Characteristics of Two-Phase Flow Distribution in Compact Heat Exchanger [J]. International Journal of Heat and Mass Transfer, 2009, 52(1-2): 442-450.
[10] 严瑞东，徐博，陈江平，等. 微通道换热器两相分配特性对空调系统性能的影响［J］． 制冷学报, 2013, 34(3): 20-23．
Yan R D, Xu B, Chen J P, et al. The Impact on Air Conditioning System of Two-phase Distribution in Microchannel Heat Exchanger [J]. Journal of Refrigeration, 2013, 34(3): 20-23.
[11] Rin Y. Comparison of performance of a residential air conditioning system using microchannel and fin-and-tube heat exchanger [C]. International Refrigeration and Air Conditioning Conference，Purdue，2006: 1-8．
[12] 王颖，徐博，陈江平，等．微通道换热器用于家用柜机空调时整机性能的对比实验研究［J］. 制冷学报, 2015, 36(1): 24-29.
Wang Y, Xu B, Chen J P, et al. Experimental Research of Microchannel Heat Exchanger on Packaged Air Conditioning System [J]. 2015, 36(1): 24-29.
[13] Kim M H, Bullard C W. Air-side thermal hydraulic performance of multi-louvered fin aluminum heat exchangers [J]. International Journal of Refrigeration, 2012, 25(3): 390-400.
[14] 刘巍，朱春玲. 内部结构对微通道平行流蒸发器性能的影响 [J]. 南京航空航天大学学报, 2012, 44(6): 893-897.
Liu W, Zhu C L. Effects of Inner Structure on Performance of Micro-channel Parallel Flow Type Evaporator [J]. Journal of Nanjing University of Aeronautics & Astronautics, 2012, 44(6): 893-897.
[15] 殷辉. 微通道换热器的R404A制冷系统性能研究[D]. 天津商业大学, 2013.
Yin H. Performance Study on The R404A System with Microchannel Heat Exchanger [D]. Tianjin University of Commerce, 2013.
[16] Falsetti C, Jafarpoorchekab H, Magnini M, et al. Two-phase operational maps, pressure drop, and heat transfer for flow boiling of R236fa in a micro-pin evaporator [J]. International Journal of Heat and Mass Transfer, 2017, 107:805-819.
