As their name suggests, high volume, low speed (HVLS) fans tend to have larger diameters and move slower than their traditional counterparts. These fans are commonly used in large spaces such as manufacturing facilities and shopping centres. They are not only beneficial for occupants, but they can also result in energy savings for management.
Here, Dean Wood of Envira-North Systems Ltd. explains how HVLS fans are used, and what benefits that can bring to a building.
In what settings are HVLS fans commonly used?
High volume, low speed fans are typically installed in large structures with high ceilings and open spaces. Originally designed for use in dairy barns for cow comfort, the technology has evolved into its current form. Applications in manufacturing facilities, warehouses, distribution centres, airplane hangars, airports, shopping malls, atriums, hockey arenas, indoor swimming pools, gymnasiums, big box stores and car dealerships are not uncommon.
In physical terms, how does an HVLS fan differ from an average fan?
Aside from the obvious size difference, HVLS fans can offer unique efficiencies never before seen in air movement. All reputable fan companies provide volume displacement ratings describing the capabilities of their product. For example, a traditional three bladed 56-inch ceiling fan can move upwards of 15,000 cubic feet of air per minute (CFM). In comparison, some HVLS models can move 397,701 CFM.
Also, replacing the traditional two speed controls with variable frequency drives (VFDs) enables HVLS fans with greater control, while creating additional energy savings for the operator.
What are the main benefits of using this type of product?
Considering our specific climate here in Ontario, HVLS fans can provide two main sources of energy efficiency. In the winter, HVLS fans are utilized at low speeds to de-stratify hot air at ceiling level. The hot air is pushed back down to ground level (where it is needed) and generates upwards of 40 per cent savings on heating. It has proven successful in hundreds of applications across Ontario, to the point where natural gas providers now offer rebates for customers who install the technology.
Conversely, in the summer, fans are deployed at high speeds to create a more comfortable environment for the occupants of the structure. Much more efficient than traditional circulation fans and again proven successful in applications province-wide, local electricity suppliers offer additional rebates as mandated by the Ontario Power Authority.
Is it better to use an HVLS fan on its own or in conjunction with an HVAC-R system?
When used in conjunction with any HVAC-R system, HVLS fans improve the efficiency of that system. Heating and cooling consumption is decreased, ventilation rates are maximized and the air envelope is evenly mixed.
However, in the event where HVAC systems are not present, for example in dairy barns, HVLS fans present a unique opportunity to significantly improve the comfort level for the occupants.
Dean Wood is the sales manager for Envira-North Systems Ltd. in Seaforth, Ont. Wood presents information on HVLS fans regularly to audiences in Asia and the Middle East, and he has spent time educating engineers and end-users. He can be reached at [email protected].