Reflecting on the benefits of VRF
Such has been the growth in VRF air conditioning in the UK that it is now the second largest sector in this market. Recent figures from BSRIA value the VRF market at £87 million a year — about 17% of the market. In achieving that second place, VRF has overtaken chillers in value terms and is also making ground on the traditional commercial split sector. We asked Mike Nankivell, business development manager with Space Airconditioning, which distributes Daikin products, why he thinks VRF [VRV in Daikin parlance] air conditioning is growing in popularity. One of the principal benefits he highlights is the enormous flexibility made possible by the modular nature of VRF. Compared with central plant, such as a large chiller, the outdoor condensing units of a VRF installation can be widely spread. This feature, explains Mike Nankivell, enables the outdoor units of individual systems to be installed where space is available, which is particularly helpful in refurbishment projects. The maximum cooling capacity of a VRF system is around 150 kW, but several systems can be installed to serve buildings with larger cooling capacities. The longer pipe runs and greater vertical displacements that have made possible by continuing development have also increased the scope of VRF. Total pipe runs of some 150 m (175 m equivalent) can be considered for a 150 kW system. There can also be a 50 m height difference between indoor and outdoor units, with 15 m difference between the highest and lowest indoor units. Mike Nankivell also points to the benefits of VRF’s capability of delivering cooling, heating and heat recovery. He says that using a VRF system to provide heating incurs a marginal extra capital cost, but that this is considerably less than separate boiler plant. There is also no need for pumps to move hot water. The logistics of installing a VRF system compared with one based on chilled water are also simpler. Mike Nankivell indicates that the installation of a chilled-water system requires about 16 different disciplines, compared with an installer and equipment supplier for VRF.