Access Exclusive Member Content Ceilings, Furniture & Walls Equipment Rental & Tools Part 1: HVAC: A Closer Look at VRF Technology Managers Must Consider Benefits of VRF System for HVAC Upgrades Application Insights for VRF Systems HVAC: A Closer Look at VRF Technology Part one of a three-part article on VRF technology By Mark Stavig, P.E. Energy Efficiency   Article Use Policy Variable-refrigerant flow (VRF) systems are an emerging technology in the U.S. HVAC market and are gaining the attention of maintenance and engineering managers in institutional and commercial facilities. The systems are designed to increase energy efficiency and can heat and cool separate spaces simultaneously.A Japanese company developed VRF in the early 1980s as variable-refrigerant volume before manufacturers renamed the technology. VRF systems circulate the minimum and correct phase of refrigerant required by the indoor unit to allow for individual climate control within large air-conditioned systems.

Early-generation refrigeration HVAC systems consisted of splitting one indoor unit and one outdoor unit connected by two copper pipes. The pipes used a constant-speed compressor to circulate refrigerant.VRF systems use a balancing box to control the heating and cooling refrigerant for each indoor unit. The basic concept separating VRF systems from other choices is the ability to vary refrigerant volume through the use of inverter-driven compressors and individual outdoor units equipped with flow-regulating valves. central air conditioning sizing tutorialVarying the flow within a system allows multiple indoor room devices to be assembled into one large system, much the way central hydronic plants operate in larger facilities.wall ac unit 12000 btuWithin one system, the heating required in one room can be obtained from the heat-absorption output from another room’s cooling needs. ruud hvac units

All rooms with VRF systems feature full cooling and heating, but they provide the best energy savings when they share energy.Indoor units feature small fans that operate quietly and do not require the use of air ducts because they are served by small refrigerant piping. Since a refrigerant’s heat capacity is higher than that of air or water, duct and fan sizes throughout buildings are reduced. Since the outdoor unit acts as a single source of heating and cooling, multiple chillers, boilers and pumps are not required to flow water through large piping systems.In a two-pipe VRF system, up to 60 room devices can connect to one balancing box. A set of valves inside the balancing box controls whether an indoor unit receives super heat gas or saturated gas. The balancing box then connects to an outdoor unit with two pipes. The outdoor unit provides the cooling or heating needed by the balancing box to support the system.  A three-pipe system connects the balancing box with the indoor unit using heating, cooling, and return pipes.

Manufacturers continue to expand the capacity and flexibility of the systems and devices to meet the varying applications of the systems. The demand for more flexibility in HVAC systems directed managers to above-ceiling concealed units connected with multiple diffusers or rooms. VRF options include wall-mounted, floor-mounted concealed, and floor-mounted exposed units. VRF technology development later expanded to water-source units that offer the ability to heat or cool water while rejecting energy to the refrigerant piping. A new VRF option features a refrigerant coil that connects to a large air-handling unit and VRF piping. Part 2: Managers Must Consider Benefits of VRF System for HVAC Upgrades Part 3: Application Insights for VRF Systems Find us on Google+ Set Free Variable Refrigerant Flow (VRF) systems by Hitachi are an extremely powerful cooling solution for all kinds of residential, industrial and official establishment units. These systems are designed to thoroughly save on energy usage while being reliable, flexible and easy-to-install.

2016 Energy Star manufacturer of the yearMJC, Inc. is proud to introduce the game changing multizone – CONVERGENCE – A Packaged VRF Multizone unit configured in a classic multizone layout for both New and Direct Replacement markets. MJC has combined the efficiency and reliability of a VRF system into a roof, pad, or indoor mounted package unit. VRF technology can reduce the energy consumption by as much as 40% a year compared to traditional DX systems. VRF technology yields exceptional part-load efficiency. Since most HVAC systems spend most of their operating hours between 30-70% of their maximum capacity, where the coefficient of performance (COP) of the VRF superior to traditional DX systems.  VRF systems also offer much higher part load performance’s (IEER) than traditional DX systems. For example, traditional air-cooled unitary air conditioners between 10 and 25 tons have full load efficiencies of 11 EER and part-load efficiencies of 12.0 IEER.  VRF systems have full load efficiencies up to 13 EER and part-load efficiencies up to 30 IEER.

The MJC Convergent Multizone VRF system allows end users to take advantage of these higher efficiencies to lower utility costs and speed project payback. MJC’s Convergence Packaged VRF Multizone unit allows end users to take advantage of VRF technology without the associated inconveniences of typical VRF systems. By providing a roof mounted multizone solution, it keeps service technicians out of the occupied space during maintenance. It eliminates the need for condensate pumps and drains being located in the occupied space.  This keeps the space from having clogged drains in multiple locations in the occupied space. All drains from individual evaporators are located in MJC’s Convergence unit making maintenance and cleaning easy and convenient. MJC’s Convergence Packaged VRF Multizone answers ASHRAE Standard 15 Compliance concerns that traditional VRF systems have. Refrigerant piping is out of the airstream and out of the space being served. Our unit takes advantage of VRF solution without long refrigerant runs and high refrigerant charges.

In traditional two deck multizone applications, units blend hot deck air and cold deck air together potentially wasting energy from having mechanically cool and heated air mix together to maintain zone temperature. In todays market, simultaneously heated and cooled air is not allowed per code (California Title 24 and others), multizone units must be equipped with an ambient lockout, setting a changeover point where heating or cooling is enabled. This leads to periods of less than optimum zone temperatures. MJC’s Convergence Packaged VRF Multizone system excels by using the heat recovery feature to provide simultaneous heating and cooling without necessarily running the units compressors. Independently heat and or cool each zone regardless of ambient condition or conditions in other zones and do so without increasing energy usage. When some zones are calling for cooling, heating is available for free in a sense. Instead of rejecting heat to the outdoors, reject heat to zones calling for heating.