Performance evaluation of the variable refrigerant flow (VRF) air-conditioning system during the heating-defrosting cyclic operation
Performance evaluation of the variable refrigerant flow (VRF) air-conditioning system during the heating-defrosting cyclic operation
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DOI：
10.1299/jtst.2017jtst0035
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发表时间：
2017
影响因子：
1.2
通讯作者：
N. Enteria;H. Yamaguchi;M. Miyata;T. Sawachi;Yasuo Kuwasawa
中科院分区：
文献类型：
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作者：
N. Enteria;H. Yamaguchi;M. Miyata;T. Sawachi;Yasuo Kuwasawa
2017年日本机械工程师学会[DOI：10.1299/jtst.2017jtst0035]本文介绍了变制冷剂流量空调系统在室外极低温度下的性能评价。本研究的目的是了解供暖-除霜循环运行对变风量空调性能和室内环境热状况的影响。以一台室外机和两台室内机的VRF空调系统为试件，在温湿度控制的试验室中进行试验。从恒定的干球温度和不同的湿球温度，以及在干球温度和湿球温度不同的情况下，进行了几个试验案例。研究结果表明，供暖-除霜循环运行影响了变风量空调系统的性能。结果表明，加热时间随干球和湿球温度的变化而变化。结果表明，对于不同的干球和湿球温度，不同的加热时间，除霜时间基本相同。循环加温除霜通过降低除霜过程中的室内温度来影响室内温度。根据结果，需要采取必要的措施来解决除霜对VRF空调系统性能和室内热环境状况的影响。在温带气候条件下，VRF空调系统安装在实际建筑中时，往往会发生供暖融霜循环运行，在评估不同VRF空调系统在此条件下的性能时，了解其对系统的运行行为、能耗以及对室内环境热状况的支撑作用具有重要意义。
Paper No.17-00269 © 2017 The Japan Society of Mechanical Engineers [DOI: 10.1299/jtst.2017jtst0035] Abstract This paper shows the performance evaluation of the variable refrigerant flow (VRF) air-conditioning system subjected to very low outdoor air temperature at which the heating-defrosting cyclic operation occurred. The objectives of the study are to know the effect of the heating-defrosting cyclic operation in the VRF airconditioning performances and of the indoor environment thermal conditions. The one outdoor unit’s and two indoor units’ VRF air-conditioning system was used as a test specimen in the controlled testing chambers in which temperature and humidity were controlled. Several test cases were done covering from constant dry bulb temperature with different wet bulb temperature and for both dry bulb temperature and wet bulb temperature different. The results of the study show that the heating-defrosting cyclic operation affected the performance of the VRF air-conditioning system. It shows that the heating time changes depend on both dry bulb and wet bulb temperatures. It shows that the defrosting time is almost the same for different dry bulb and wet bulb temperatures for different heating times. The cyclic heating-defrosting operation affected the indoor air temperature by lowering the indoor air temperature during defrosting. Based on the results, necessary measures are needed to address the effect of the defrosting in the VRF air-conditioning system performance and of the indoor thermal environment conditions. The heating-defrosting cyclic operation is expected to occur when the VRF airconditioning system is installed in an actual building in a temperate climate, and in the performance evaluation of the different VRF air-conditioning systems under these conditions, it is important to know how it affects the system’s operation behavior, energy consumption and support of the indoor environment thermal conditions.