Variable refrigerant flow systems – the innovative way to heat and cool your building
Variable refrigerant flow systems : For many owners of large commercial buildings, going green and saving green are often difficult to achieve at the same time. While cost savings can be attractive, eco-conscience infrastructure upgrades can be expensive to install and maintain. For those looking to cool and heat an office building and save money and energy while doing it, Variable Refrigerant Flow equipment, or VRF, is an increasingly popular option.
VRF technology is relatively new in the United States, but it has existed in Japan and elsewhere overseas since the 1980s. Unlike standard HVAC systems that generally function as cooling only with compressors cycling on and off, VRF systems utilize inverter compressor technology with electronic expansion valves, creating fully modulating systems that can provide cooling and low-ambient primary heating. VRF’s ability to modulate and control refrigerant allows many indoor units to be connected to one (or multiple) condensing units with very long pipe lengths for flexible zoning of a system. This allows for varying degrees of cooling and/or heating in different areas, which saves on energy costs, particularly with office space since various spaces can have vastly different occupied/unoccupied schedules.. It also gives tenants the power to cool and heat specific rooms or areas in the office based on preferred setpoint, occupant load/density, room position on floorplan/building exposure, and (but not limited to) occupied/unoccupied scheduling.
There are two types of VRF systems: heat pump and heat recovery. Both types are available with air source or water source condensing units. A heat pump system can provide heating or cooling and all indoor units must be in the same heating/cooling mode. A heat recovery system allows indoor units to simultaneously operate in heating or cooling mode, providing operation by utilizing changeover boxes, which are positioned in the system between the condensing unit and indoor units. Changeover boxes act as the “traffic controller”, efficiently directing refrigerant in various phases through electronic expansion valves to different indoor units which require heating or cooling.
Both air source and water source VRF condensing units present an excellent opportunity for flexible office building layouts, even for large tonnages and high density areas. Air source condensing units can be located on the roof, setbacks, and indoors ducted behind louvers (either floor-by-floor, or grouped in dedicated mechanical rooms). Water source condensing units can also be clustered in mechanical rooms or spread out in small closets for floor-by-floor installations. Water source units utilize condenser water systems and can be retrofitted into existing buildings in conjunction with other water source equipment like packaged units. This allows for gradual fit-out of a high-rise building and the flexibility for tenants to build out their system as needed.
VRF systems also lead the industry in sound with low-noise ducted or ductless indoor units distributed throughout the space, and generally louder condensing units located in less sound sensitive areas. Condensing units utilize ECM condenser fans, and inverter compressors with multiple levels of sound dampening to have the flexibility of being placed almost anywhere with the peace of mind that occupants won’t be disturbed.
VRF also gives owners a competitive advantage in a tight end user market. As building owners look to deliver more tailored experiences, comfort is a major value-add for VRF. With precise load matching through inverter compressors, fully modulating EXVs in each indoor unit, and the ability to simultaneously heat and cool each space, VRF systems provide an industry-leading level of comfort and control. The latest rebate programs from local utilities also provide impactful incentives for making the switch to VRF for new and existing buildings.
The utilization of VRF is rapidly growing in the North American market at a time where high efficiency and electrification is needed to comply with local laws and mandates to avoid costly penalties. A building with a VRF system has a critical advantage at a time when tenants are increasingly considering air quality, comfort, and energy savings. For owners looking to retrofit to become Local Law 97-compliant and win the arms race for corporate end users, VRF is a strategic consideration in a new market landscape.
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