One of the most interesting new HVAC trends is the use of VRF systems. While the use of these systems is fairly new in North America, they have been deployed in other parts of the world for years. In fact, in Asia, where the concept was developed, they have been widely used for decades.
The concept of a VRF system is an extension of the ductless mini-split, where you have a packaged condensing unit connected to an indoor fan unit, which is mounted on the wall or in the ceiling grid. In a VRF system, the same ductless indoor units are used but a single outdoor condensing unit serves a group of them. The system can be configured to provide cooling or heating (heat pump) at any unit, as well as heat recovery. The outdoor units typically have one or more variable speed compressors and the ability to match the loads of the interior units. System suppliers are starting to offer more and more options with VRF, including a variety of indoor units and outdoor units that are either air or water-cooled.