Timberline Blog

An Intro to VRF: Intelligent Heating and Cooling through Energy Transfer

Variable refrigerant flow (VRF) is an HVAC technology in which one outdoor unit is connected with multiple indoor units, and the flow of refrigerant is automatically shifted from one zone to another to efficiently transfer heat away from areas needing cooling and into areas needing heating. The refrigerant is conditioned by the single outdoor condensing unit, and then is circulated within the building to multiple indoor units such as fan-coil units (FCUs), air handling units (AHU).

Also known as variable refrigerant volume (VRV), the system was developed in the 1980s and initially used almost exclusively outside the U.S. Since that time, it has been modified and enhanced, and now represents the cutting edge of HVAC in the U.S. Its efficiency in simultaneously meeting heating and cooling demands, and the level of control it provides to building occupants, are impressive.

General Benefits of VRF

In a VRF system, the compressor supports variable motor speed, which allows for variable refrigerant flow, as opposed to the typical on/off operation (or at best a few stages) of conventional heating and cooling systems. As a result, VRF units work only as much as they need to in order to maintain the desired temperature at a location.

This provides substantial energy savings when less than full-fire operation is needed, which is almost always the case in Colorado. Along the Front Range, there are very few days where the temperature extremes require sustained full-fire activity. By some estimates, energy reduction of as much as 55 percent can be achieved with a VRF system.

Another benefit of VRF is the granularity of the heat/cold adjustments. The system’s design allows users to easily adjust the temperature in a particular location in a building rather than having to raise or lower it in a large area. What’s more, VRF systems are “intelligent,” and continually report on their performance. This allows building owners or managers to further optimize energy consumption and lower costs.

Air-Cooled vs. Water-Cooled VRF

VRF systems come in two types: air-cooled and water-cooled. With an air-cooled configuration, there must be ample exterior space for installation of the condenser unit. In addition, the installation site must be capable of supporting the weight of the units, away from windows, and accessible for maintenance tasks.

Water-cooled VRF systems are an excellent option where outdoor space is limited, building heat recovery and efficiency is desired, and a water loop is available. They can be designed to take advantage of geothermal energy sources, rivers or lakes, waste heat from computer server cooling, and other processes. With water-cooled VRF, there are compact, quiet units on each floor. This minimizes the use of outdoor space and maximizes the use of potentially vacant indoor areas such as closets.

VRF HVAC Providers

A number of companies provide VRF technology. Mitsubishi is one of the leaders in the field. The company offers a variety of systems, including its City Multi (for “multi range”) system, designed for larger installations. Its latest technology includes many advances, and delivers benefits such as:

• Wide range of capacities
• Many types of indoor units with varying capacity: ducted, floor standing, wall-mounted, ceiling cassettes, ceiling suspended, and air curtains
• Ability to connect as many as 50 indoor units to one system
• Selectable system evaporating temperature for increased air off temperatures, greater comfort, and energy savings
• Choice of two defrost methods: traditional reverse defrost or the new hot gas defrost technology
• Compact and decentralized modules
• Flexible piping configuration
• Intuitive control solutions that users can access 24/7 through the internet
• Intelligent rotation of the master unit to ensure equal operation of individual units
• Exceptional reliability and easy maintenance

The City Multi VRF system is state-of-the-art, and just starting to make its way into Colorado’s Front Range. At this point, only 8-10 companies are taking advantage of its benefits. However, many more are beginning to understand what variable refrigerant flow offers and looking into making the switch. While the initial cost of a VRF system is higher than a conventional heating and cooling system, the energy cost savings quickly make up the difference, with ongoing savings moving right to a company’s bottom line.

The Importance of VRF Certification

While the concept of VRF heating and cooling (i.e. moving heat away from where it is not needed to where it is needed) makes perfect sense and is simple in theory, properly installing a VRF system requires specialized skills and training. Companies like Mitsubishi that provide this kind of technology offer product training and certification to ensure that installers and technicians are well-versed in their products.

At Timberline, we have earned what is referred to as “M&P” certification for smaller VRF systems. We’re also a certified installer for the larger City Multi system. Not only does certification benefit our customers in terms of our technical proficiency, Mitsubishi also provides an enhanced warranty to companies whose work is performed by a certified HVAC provider.

We are currently involved in the installation of a water-cooled City Multi R2 System with heat recovery. When the project is complete, we will share information on this exciting project in another blog post.

To learn more about variable refrigerant flow technology and the efficient heating and cooling it can provide for your business, contact us today.

Tags: city multi VRF air conditioning, heat recovery system, heating and cooling system, variable refrigerant flow (VRF), VRF heating and cooling systems, VRF systems, water cooled VRF