Variable Refrigerant Flow (VRF) Systems

New regulations and customer expectations are changing the way that commercial facilities managers tackle the challenges of temperature control. Once-common refrigerants are being phased out due to environmental concerns. At the same time, new technologies raise efficiency in innovative ways.

One of the most important concepts popularized over the last few years is VRF – variable refrigerant flow. VRFs have taken the air conditioning and heat pump market by storm in the United States. Soon, they might completely change how we plan and implement commercial HVAC systems.

VRFs Offer a Chance to Resolve a Common Problem in Large Commercial Buildings

When you’re managing a large commercial building with multiple tenants, you’re bound to have many different ideas of what the “ideal” temperature is. Facilities leaders have to balance the fickle issues of tenant comfort with an energy efficiency strategy that yields results.

That’s precisely where VRF systems come in.

Using VRFs, one outdoor compressorized unit can service several indoor fan coils, each equipped with its own individual thermostat. That lets you divide the space into multiple, fully independent control zones, closely matching the tenancy makeup of the building.

You can even go as far as to provide thermostats for every room.

That may be the biggest selling point for most users, but there are other advantages:

  • VRF systems require less space than conventional alternatives while doing more work.
  • The VRF compressor can be sited outside, fairly distant from the rooms it will service.
  • Fan coils use relatively quiet variable speed motors that feature a quiet cycle startup.

How Does a Variable Refrigerant Flow System Fit Into The Efficiency Equation?

VRFs are extremely efficient, providing the flexibility to heat one space while cooling another at little additional energy expense. They can simply pump heat captured in the cooling zones to the areas in the building that need it. Where roof space is available, they can support continuous ventilation and simply cycle off when no load is present in the space.

How does a VRF achieve this kind of flexibility? The underlying technology is intuitive.

Fundamentally, a VRF system acts as a heat pump. When the unit is in cooling mode, the indoor fan coil works as an evaporator unit in concert with the outdoor unit, which takes the role of the refrigerant condensing unit. In heating mode, these roles are reversed. Since both the outside and inside units use variable speed motors, they’re great at operating at partial load.

Here in New York City, more large commercial structures are adopting VRF systems to help cut down on energy waste and meet ambitious efficiency targets. To learn more about these systems and how they can help you, call or email Donnelly Mechanical.

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