Investigation of VRF system cooling operation and performance in residential buildings based on large-scale dataset

Abstract

With the increase in the energy consumption of air-conditioning (AC) systems in Chinese residential buildings, the realization of energy savings in AC systems has attracted increasing attention. The variable refrigerant flow (VRF) system is a common AC system for residential buildings in China. In most previous studies on VRF systems, onsite measurements or surveys were conducted to collect operational data. These traditional methods may face various data issues, such as limited sample sizes and invalid data, making them unable to capture the spatial and temporal performance features of VRF systems in residential buildings on a large scale. To fill this gap, with advances in data storage and transmission technology, Big Data methods have been widely used for data collection. In the present study, researchers adopted 16,985 sets of VRF system operation data from China as the database and conducted data analysis for both the spatial and temporal dimensions. Several key indicators were proposed from the two perspectives (spatial and temporal), including the part-space index (PSI), load ratio (LR), use duration (UD), and cooling energy consumption. The main findings were as follows: (1) The “part-time part-space” operation mode of residential VRF systems can be analyzed according to the statistical results of the UD and PSI. (2) An LR of <30% is the main operating condition for VRF systems in residential buildings. (3) Extracted typical LR patterns can reflect different user behavior. The statistical results obtained in this study provide a basis for VRF engineering projects.