Variable refrigerant flow (VRF) systems are popular options in both residential and customer facilities. These systems are essentially improved versions of multi-split systems and use refrigerant to heat and cool buildings. They can operate as heat pumps (heat or cool only) or with simultaneous heating and cooling based on various needs throughout the building. This allows for precise zoning for maximum thermal comfort. VRF systems consume very little energy as demonstrated on energy bills. VRF systems can easily be added into existing or future BAS. Additionally, VRF HVAC technology minimizes the necessary ductwork and excludes the need for chilled/hot water distribution and any associated costs.
VRF consists of a single outdoor unit, single or multiple indoor units serving different zones, and refrigerant piping with branch selectors and associated controls. The outdoor unit consists of the compressor, which compresses the refrigerant, and an indoor unit that acts as an evaporator. Each outdoor unit may be connected to multiple indoor fan coil units. The outdoor unit can have one or multiple compressors. These compressors are typically inverter-driven scroll or reciprocating units, which means they use a drive to control the compressor’s motor speed and modulate the cooling capacity. These compressors are usually scroll or reciprocating. The speed is varied based on the power supply frequency to the compressor. As the compressor speed changes, so does the refrigerant flow delivered by the compressor to the indoor units.