IN-24-C035 - Cooling Energy Consumption and Efficiency of VRF Systems Based on a Large-Scale Dataset

The cooling energy consumption of buildings is rapidly increasing. The cooling energy consumption of China is a significant part of global building cooling energy consumption. To reduce the cooling energy consumption of buildings, it is necessary to fully understand the actual application of cooling energy consumption and efficiency and to find the key factors of cooling energy consumption and efficiency, which would help optimize air conditioning system design and operation to reduce cooling energy consumption in buildings. To fill this gap, statistical analysis and data mining were conducted on the operation data of 6544 VRF cooling systems for residential buildings in China. The distribution of cooling energy consumption and cooling efficiency in different regions of China is analyzed through a large amount of VRF cooling operation data. The distribution of cooling efficiency in different regions is analyzed. And the paper proposed key indicators of part time part space ratio of air conditioning, outdoor temperature with air conditioning cooling, and cooling load ratio of air conditioning is proposed to quantify the influence on the cooling energy consumption and efficiency. The main findings are: (1) The actual cooling operation power consumption of the VRF system gradually increases from north to south across China, which is linearly related to the key indicators of part time part space ratio of air conditioning in different regions. (2) The cooling operation efficiency in China is between 2.99~3.58. The efficiency difference of each province does not exceed 20% because of the similar outdoor temperature with air condition cooling, which is mainly between 26.5°C~32.5°C, and similar cooling load ratio, which is mainly distributed between 26%~44%. (3) The actual energy efficiency of the VRF system is lower than the rated efficiency. The analysis shows that the cooling is related to the low-efficiency operation of the VRF system under partial load, which is related to the "part-time part-space" use mode of the VRF system users in residential buildings. It is necessary to design the air conditioning according to the users’ behavior of cooling in residential buildings.