Abstract: Refrigerant flows directly into a few indoor units to make heat exchange with air through long pipes in a variable refrigerant flow system (VRF). Under circumstances of high temperature, VRF faces challenges in safety and reliability due to dramatic voltage fluctuation by electricity peak load and regional difference. The on-off dynamic operating behavior with high temperature and voltage fluctuation was mainly experimentally investigated for a VRF (24 HP), while some performances during the initial stable stage were also shown. Results showed that the VRF operates safely in accordance with the controlling logic of capacity requirement, outdoor environment temperature, internal pressure, voltage supply, etc.

Key words: VRF, High temperature, Voltage fluctuation, Dynamic performance