Colleges, Universities Warm Up to Variable Refrigerant Flow Systems

Several factors are driving the popularity of this versatile technology in the selection of HVAC for student housing retrofits and group-up projects.

Unlike conventional HVAC systems that don’t allow operators to target individual areas, VRF uses only the precise amount of energy needed for each interior zone. Image courtesy of Mitsubishi Electric Trane HVAC US

Student comfort, system management and sound levels are top of mind when colleges and universities select HVAC equipment for their projects. Other factors include indoor air quality, energy efficiency and cost savings. All of these drivers are leading colleges, universities and developers to investigate and install Variable Refrigerant Flow (VRF) systems.

VRF technology is appropriate for a variety of applications in small- and large-scale developments and in new construction, as well as retrofit and even historical renovation projects.  VRF meets operators’ need for compact units, quiet operation and energy savings while also providing superior comfort for students.

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These benefits of VRF were discussed last week during a webinar produced by the InterFace Conference Group. Richard Kelley of Student Housing Business Magazine moderated a discussion with panelists Brian Wright, director of educational sales for Mitsubishi Electric Trane HVAC US (METUS) and Joe Shivell, vice president of architecture and engineering for The Michaels Organization.

Heating and Cooling Multiple Zones

VRF systems move conditioned refrigerant though small-diameter piping to zones requiring heating or cooling and use only the precise amount of energy needed to keep each interior zone at the desired temperature, according to Wright. These systems consist of outdoor units connected to a network of indoor units that can be ducted, ductless or a combination of the two—and they can offer a variety of layout configurations for a building.

Conventional HVAC systems, on the other hand, typically take a centralized approach where ductwork is connected to a centrally located air ventilator. “The more ductwork you have, the more potential you have for air leakage costing you efficiency and comfort,” Wright said. “When there is an issue with the system and you have all that extra ductwork, it makes it way more difficult for contractors to pinpoint the problem.” In addition to that, in conventional systems, the method of on or off operation—meaning that when the set point is reached the conventional system turns off until the temperature is at its threshold—is extremely inefficient.

According to Wright, the VRF technology on allows the operator to modulate the compressor using only the amount of electricity that is required. “This is not only extremely efficient, it also allows for greater comfort,” he noted. VRF is quieter, too.

Student housing applications generally require simultaneous heating and cooling because there is so much, and such varied, activity going on in the building. On a single floor there could be students working out (who need cooling) and also residents in the living areas who require heating.

A distinguishing benefit of VRF operation is its ability to reach the set point faster than a conventional HVAC system; and with VRF there is minimal temperature fluctuation which means a more efficient use of energy. Image courtesy of Mitsubishi Electric Trane HVAC US

“VRF has the ability to cool the room needing air conditioning and, through the branch controller, take that heat to another room requiring heating,” Wright explained. “It moves the energy from one side of the building to the other without exhausting it out. No other technology can do this.”

Personalized heating and cooling for multiple zones in a building is achieved by cycling refrigerant via refrigerant lines between the outdoor unit, the branch controller and the indoor unit.

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Wright also noted that VRF is especially relevant right now during the pandemic, when colleges and universities have fewer residents. A facility can run the gamut from limited capacity with no one inside the rooms to full capacity.

VRF outdoor equipment options include air-source (heats and cools refrigerant with air) or water-source (relies on chilled or heated water to regulate refrigerant temperature). “If your staff is used to working on traditional split systems or rooftops, air source may be a better solution,” Wright said. “But if they are used to working on geothermal or chilled water, then water source may be the way to go.” Both options provide optimal energy efficiency and comfort.

Indoor unit options are designed to fit any style and aesthetic preference and having a range of equipment is key for developers, engineers, architects and owners, Wright noted. VRF offers both ductless and ducted systems with classic wall-hung units as well as horizontal ducted units. All units have a slim profile and they are completely unseen.

Choosing Mechanical Equipment

 The Michaels Organization works with colleges and universities across the country. Looking at the big picture, they are seeing a requirement for high performance-based systems that have an extended lifecycle—and sustainable environments are gaining popularity across campuses.

According to Shivell, there are two levels of need. “As we engage facilities in the process, they are looking to either find systems that support existing demand on their central plant or that are independent and help take the demand off of aging infrastructure. Those are the typical themes we encounter.”

VRF achieves personalized heating and cooling for multiple zones in a building by cycling refrigerant between the outdoor unit, the branch controller and indoor units. Image courtesy of Mitsubishi Electric Trane HVAC US

Campuses also seek energy savings, lower utility bills and lower maintenance costs to help drive down the cost of housing on campus. Whether it’s the college or university building it themselves, or Michaels as a developer is providing that service, the campus typically sets their targets through standards and guidelines for either LEED certification, Passive House or targets to hit on the Energy Use Index. Michaels works with them to find the right equipment to help meet their goals and strategic objectives.

 Two main issues facing campuses are affordability for students and deferred maintenance across their campus, according to Shivell. “The choice of mechanical equipment obviously is the first cost and has a direct impact on how much the campus, or we as a developer, can charge for student rent on those beds”.

The pandemic has made matters worse with tighter budgets and less staff. “It has compounded the problem certainly on the deferred maintenance side. There is significant aging infrastructure,” Shivell noted. VRF can help by taking a building off the campus network so it operates independently and more affordably.

Likewise, VRF’s ability to manage and shut down specific zones of a building is a plus that traditional systems do not offer. It is especially helpful now as online learning due to COVID-19 has reduced occupancy across the board on college campuses. VRF technology can help colleges and universities stay competitive with comfortable housing while also preparing for an uncertain future.

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