By: Thomas Conn, Field Engineer, NYC Office
Variable Refrigerant Flow, commonly referred to as VRF, is a method of heating and cooling spaces that is quickly gaining acceptance and popularity in the United States. Although VRF, which uses refrigerant in either a subcooled liquid or superheated vapor state to heat and cool spaces, was invented in Japan in 1982, it was only introduced to the United States in the 2000s. This “new” technology spread quickly across several large markets and is now a viable option for heating and cooling in almost any application.
What is VRF?
The concept of VRF is a rather simple, and literal, expansion of the tried and true refrigeration cycle. It should be explained by comparing it to a traditional chiller system first: instead of the evaporator being a heat exchanger where the refrigerant cools down water to be pumped through terminal units to cool a space, the refrigerant flows through coils inside an “Indoor Unit” which blows air taken from the conditioned space over the coils (which are acting as the evaporator), cooling the air and heating the refrigerant. The refrigerant travels back up to the “Outdoor Unit” to be pressurized by the compressor and reject heat to the atmosphere in the outdoor unit’s coils (this takes the place of a condenser in a traditional system)...