Experimental Investigation of Multi-Functional Variable Refrigerant Flow System

The variable refrigerant flow (VRF) systems have a broader flexibility in control and a wider range of capacity modulation. In this study, a multi-functional VRF (MFVRF) system, which is capable of heat recovery operation and water heating, was experimentally investigated. The MFVRF system could supply space cooling and heating simultaneously in multiple zones, as well as provide hot water. The system’s performance during the experiment was measured and discussed. We found that the partial load performance of the system was improved with water heating capability, which increased the daily performance factor (DPF) by 17 percent. We also found that the system performance was enhanced by a heat recovery operation, which could increase the hourly performance factor (HPF) by reducing the pressure differences across the compressor.