Energy Savings with Variable Refrigerant Flow (VRF) Systems

Building owners are becoming more and more concerned about their building’s energy usage. Reducing the amount of energy a building uses can both help reduce annual costs for the building owner and reduce the building’s environmental impact. The largest piece of the pie for a typical commercial building’s energy is used by the heating, ventilation, and air conditioning (HVAC) system; using about 40% of the building’s total energy consumption. Therefore when a building owner is looking to reduce their energy usage, it is wise to start with the HVAC system.

Understanding how to better save energy, requires us to go back to the basic concept of HVAC systems. HVAC systems transfer heat energy from one place to another. In the winter, heat energy is transferred into the building for heat, and in the summer heat energy is transferred out of the building for cooling.

HVAC systems typically use air, water, and/or refrigerant to move this heat energy. Refrigerant is the most energy efficient of these mediums to transfer heat energy, per medium volume. Therefore Variable Refrigerant Flow (VRF) Systems are becoming more attractive to building owners for their associated energy savings.

In lieu of conditioning air or water and then sending this conditioned medium to an associated zone, VRF systems use refrigerant to move heat energy directly to or from a space. Furthering our energy savings, the refrigerant is varied to each zone to ensure that only the amount of refrigerant needed for each zone is used. The building will only use the VRF system’s full potential load for a very limited period of time drastically reducing the total energy used by the building’s HVAC system.

The energy savings does not just stop at the medium type used to transfer energy and the variability of the refrigerant to accommodate each zone’s needs. A heat recovery VRF system can transfer the heat energy with the refrigerant from a space that needs to be cooled to a space that needs to be heated.

This form of energy savings can be considered very effective for buildings that require simultaneous heating and cooling. A building can require simultaneous heating and cooling when the sun is heating one side of the building while the other side is shaded, or when a building has a heavy interior equipment or people load, while the outside temperature is low enough to call for heating in the perimeter spaces. Simultaneous heating and cooling is fairly common throughout the year for most buildings. Therefore utilizing one space’s energy to condition another can greatly reduce a building’s annual energy savings.

VRF systems, when implemented properly, can be one of the most energy efficient systems on the market today. If you have questions on VRF systems, please contact Douglas C. Barnhart, PE at (717) 845-7654 or for more information.