High-volume low speed (HVLS) fans were originally invented and introduced to agriculture and dairy processing by William Fairbank and Walter K. Boyd for improved air circulation and cooling. They patented and introduced them as high-volume low diameter (HVLD) fans back in the mid – late 90s. Modern HVLS fans still work on the same core concept, but everything else about them has evolved significantly since then.
Not only do the modern HVLS fans perform better than their predecessors, but they are also significantly more energy efficient. High-volume low speed fans are no longer just restricted to any specific industry either, thanks largely due to the wide range of sizes that they come in these days. As we take an in-depth look at the technology behind HVLS fans next, their importance and effectiveness in cooling down industrial facilities will become more apparent.
Description
A high-volume low speed fan is typically a commercial/industrial ceiling fan with three or five narrow blades, a motor, a variable frequency drive (VFD), and a control interface. Depending on the concerned, model, it may also have other components such as a smart processor and an ambient temperature sensor. The size of a high-volume low speed fan will vary between 8-feet to 24-feet in diameter, depending on its intended use, space availability, coverage area, etc.
HVLS fans can also be pole mounted if the ceiling is not an option, or if it’s being used outdoors. When used outdoors, the effects will not be as prominent as they would be in an indoor environment. However, the use of a pole mount in an indoor setting does not necessarily mean it will hamper the HVLS fan’s performance.
Functions
Businesses buy HVLS fans because they can facilitate and/or improve the useability, comfort, safety, productivity, quality, and energy efficiency of any large, enclosed commercial or industrial space. At the very least, the fans will actively:
- Provide constant cooling and air circulation.
- Maximize the energy efficiency and cooling capacity of commercial/industrial HVAC systems, when available.
- Lower energy bills by consuming less power than a high-speed industrial ceiling fan.
- Prevent dangerous moisture buildups on machines, walls, floors, and ceilings inside enclosed spaces.
- Prevent heat stress from affecting workers and thus improve their productive capacity.
- Prevent the livestock from overheating and becoming sick in dairy, poultry, and meat farms.
Buildings
Any commercial, industrial, or public space that’s large enough to accommodate HVLS fans will benefit from installing them, so its usefulness is not limited to any specific industry. For example, warehouses, manufacturing plants, food processing plants, packing facilities, barns, airport hangars, large office buildings, giant shopping malls, large restaurants, big gyms, and large indoor event venues are just some of the places that stand to benefit the most from HVLS fan installations. Note that HVLS fans are not replacements for HVAC systems. Rather, they augment the indoor cooling and ventilation by making HVAC systems significantly more effective without the need for being overactive.
Principle
All high-speed industrial, commercial, and residential ceiling fans rotate fast because their goal is to disperse air immediately and constantly at a continuous, high speed. High-volume low speed fans rotate at a much lower speed in comparison to them because they don’t use air dispersion speed to cool and circulate an indoor space.
The long and narrow aerodynamic blades of a high-volume low speed fan will instead build vertical columns of swirling air directly under them. Once a column of swirling air reaches its maximum speed and volume, it will be pushed out from below the fan and towards the walls. Immediately after its dispersal, another column of air will begin to from below the HVLS fan, thus perpetuating the process.
The swirling jet of cool air will continue to move along the floor and bounce off surfaces, until it loses enough momentum. Until then, the little tornadoes will speed up moisture evaporation and cool down anything that they come in contact with, which includes everything and everyone from walls and floors to people, livestock, and machinery. In addition to cooling and circulating air, the swirling, moving air vortices will also keep indoor moisture from settling down on any surface in layers.
Size
We now know that high-volume low speed fans range between 8 to 24 feet in general, but what kind of impact does blade size have on their practical capabilities? How is size relevant to the aerodynamic technology used by HVLS fans to achieve the cooling, dehumidifying, and circulating effect that they have on indoor air?
The speed and depth of each small whirlpool will be relative to the size and speed of the HVLS fan that created it. The HVLS fan diameter to air jet depth ratio is usually 8:3. That means, a 16-foot, high-volume low speed fan will create air columns as deep (tall) as 6-feet, while a 24-foot HVLS fan will produce air jets as deep as 9-feet.
Their speeds, on the other hand, will be close to each the fan’s rotation speed, irrespective of size. In most settings, other indoor environmental factors will alter both the speed and the depth of the air column to some degree. Also, the bigger an air column is, the longer it will last before dissipating. This means that larger HVLS fans are significantly more effective in every possible way, barring energy consumption.
Efficiency
The energy savings that HVLS fans bring to commercial and industrial facilities are tremendous. If a facility has never used high-volume low speed fans before and previously relied exclusively on high-speed fans, they will see a marked improvement in their annual energy savings and green building ratings. For example, a HVLS fan dispersing air at just 5mph will consume roughly 64 times less energy than a high-speed industrial fan of the same diameter that’s dispersing air at 20mph.
By now, it should be clear why most businesses that can benefit from HVLS fans already have them installed. The technology behind HVLS fans has improved to such a point now that high-speed fans simply cannot compete with them in any space that’s large enough to accommodate HVLS fans.
