HVLS fans work in tandem with natural ventilation or HVAC systems, but while HVAC systems can help with distributing air, there is no means of mixing it.
A turbulent, high velocity air jet dissipates very quickly. A large column of air however, travels farther than a small column. The friction between moving air and stationary air occurs at the periphery of the moving column. The perimeter of a column varies directly with column diameter, and while the cross-sectional area varies with the square of the diameter, the large column has proportionately less periphery, and therefore less “drag.” The air column from a 3-foot diameter fan has more than six times as much “friction interface” per cubic foot as does the air column from a 20-foot fan. This is why a large, slow moving fan actually cools better and more efficiently than a small high-speed fan.
Without a HVLS Fan Moving Air:
When the down column of air from an HVLS fan reaches the floor, the air turns in the horizontal direction away from the column in all directions. The air flowing outward is called the “horizontal floor jet.” Since the height of the floor jet is determined by the diameter of the column of air, a larger diameter fan naturally produces a larger air column and thus a higher floor jet. Smaller high-speed fans of equivalent displacement are incapable of producing the same effect.
With a HVLS Fan Moving Air:
Efficiency of HVLS Fans
The power to drive a fan increases roughly with the cube of the average air speed through the fan. A commercial fan delivering air at 20 miles per hour (mph) requires about 64 times as much power as a similar sized fan delivering air at 5 mph. Airspeed, combined with fan effectiveness means that when the objective is to distribute air, large, low-speed commercial fans are enormously more efficient and effective than small high-speed fans. One HVLS fan consumes about the same amount of electricity as one high-speed fan while moving more than 12 times the amount of air.
Before you decide on a specific fan, it’s helpful to see how the airflow will affect your space. AirViz, MacroAir’s virtual airflow simulation software provides you with an opportunity to actually see the potential airflow of the fans in your space. With AirViz, you get a scientifically proven recommendation on how many fans to get and where to place them in your facility.
Try AirViz by clicking the button below and try MacroAir fans in your space before you buy.