Variable refrigerant flow (VRF)

Variable refrigerant flow (VRF) systems are typically all-electric systems that use air or water source heat pumps to provide space heating and/or cooling to a building's spaces. VRF systems can condition multiple zones in a building, each of which may have different heating and cooling needs. Using sophisticated control technologies, VRF systems have the ability to modulate the amount of refrigerant sent to each zone independently and in tune with diverse and changing space conditioning loads, thereby increasing energy savings. VRF systems use refrigerant to move heat throughout a building (as opposed to water or air), which allows them to use energy more efficiently.

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Our Energy Engineer, Greg Marsicek, was interviewed by Carina Wallack of E4TheFuture for a recent blog post titled, “Smarter Energy Savings: Technology’s Expert Voices.” Greg was featured with several other experts in the field from Lawrence Berkeley National Laboratory, Google, and Mitsubishi Electric Trane HVAC US. Check out Greg’s portion of the interview below and head over to E4TheFuture for the full article.  More
Application of air source variable refrigerant flow in cold climates Variable refrigerant flow (VRF) systems use variable speed, split heat pumps to provide space heating and cooling to a building's conditioned areas. Air source VRF systems perform best in moderate climates, as they typically lose capacity and efficiency at low ambient temperatures—or moderately low wet bulb temperatures where defrost is required—and may be supplemented by an additional heat source. More
Variable Refrigerant Flow (VRF) systems have developed into a promising emerging technology. While popular in some places in the world, these systems are quite new to the upper Midwest. The systems are an innovative version of a simple split system air conditioner that utilizes variable speed compressors, multiple zone refrigerant distribution, heat recovery, and low energy fan coils to cool and heat commercial buildings more efficiently than standard split systems and heat pumps. More
This white paper outlines the optimal control strategies for designing and operating air source VRF systems in cold climates. Report number: 275-1 More