VRF stands for Variable Refrigerant Flow. A VRF air conditioning system modulates the flow of refrigerant depending upon the capacity requirements of the building. A VRF system comprises of a condensing unit sited externally and a series of multiple indoor units to provide cooling and/or heating to the occupied space. The VRF system offers a simple and flexible solution where there is a demand for a changeover capability between heating and cooling, ensuring a constant, comfortable indoor climate. They also have the ability to provide simultaneous heating and cooling the difference here being that this is achieved through either two or three pipes. A 2-pipe heat recovery technology may offer increased savings on annual running costs. Mitsubishi Electricís produce a unique water-cooled WR2 system. This system not only produces heat recovery from the refrigerant circuit but also via its water circuit, offering double heat recovery potential.