The Proprietary Roadblocks Stunting the Future of VRF Design
Before proceeding with the design of a VRF system, design engineers need to familiarize themselves with all limitations that come with such highly proprietary systems.
Variable refrigerant flow (VRF) systems have been around for decades, and VRF manufacturers continuously push the limits of energy efficiency with the release of new models. From an installation and operation perspective, VRF systems are unique — in the literal sense. The sizing of the piping and associated fittings is done using software provided by the VRF manufacturer; each fitting (i.e., tee split) is specifically engineered to split the flow of the refrigerant based on the length of piping and the capacity of the indoor units located downstream of the fitting. Each manufacturer has specific requirements related to the location (horizontally and vertically) of the fittings relative to the location of the indoor and outdoor units. One could safely assume that no two VRF manufacturers have the same requirements. What may be a viable design solution for a manufacturer may not be acceptable to another VRF manufacturer.
Regardless how different or similar each manufacturer’s installation requirements may be, VRF systems and associated piping configurations are highly proprietary and inherently limiting when it comes to future expansion of existing VRF systems. As shown in Figure 2, it’s important to note that one cannot integrate a VRF system component from one manufacturer into a VRF system provided by another manufacturer. This means that, for the life of the VRF system, a building owner can only use components (i.e., indoor units, pipe fittings, etc.) provided by the same manufacturer.