CFD Simulation of Thermal Plume of VRF Air Conditioners for Cooling Season in Semi-Closed Spaces for Erbil Climate Conditions

Abstract

The variable refrigerant flow (VRF) system is extensively utilized for the purpose of space cooling and heating in residential and commercial buildings. The VRF outdoor units are frequently placed on balconies of multi-storey buildings, and the aluminum louvers conceal them to keep the aesthetic architecture appearance. This type of installation will cause the thermal plume influence of the dissipated heat discharged from condensing units to cause high suction temperature, high energy consumption, and low coefficient of performance of the system. The numerical results showed that the discharged heat from condensing units will lead to rising thermal plume influence, causing greater suction temperatures for VRF outdoor units on top floors, even overriding the operating temperature range. It also shows that removing the inward louver in front of the discharge duct on each floor is an efficient method to deteriorate the thermal plume influence for VRF air conditioners and enhance the thermal efficiency of the entire system. For the proposed design, the average suction temperatures could be reduced by 8%, 15%, and 19% for VRF outdoor units for floors 10th, 11th, & 12th, respectively. This work aims to provide guidelines for the placement of VRF air conditioners in buildings in the designing stage.