HVLS – High Velocity Low Speed fans are designed to move a lot of air in a building to provide ventilation and perceived cooling in the environment. With correct sizing of fans, which can be supplied in diameters from 2.4 up to 7.3 metres, a gentle breeze can be felt over a wide area, utilizing the natural cooling mechanism in the body to make us feel up to 10°C cooler.
A single 6 metre HVLS fan may replace 6 standard 1 metre fans operating at high speed thus saving as much as 90% in running costs. The selected fan diameter will be determined by the building area, height to the roof or ceiling and the amount of floor space that is taken up by immoveable objects.
In applications such as large multipurpose halls there may be no existing cooling equipment. In such cases it will be much easier to install HVLS fans than for example full or evaporative air conditioning. Use of HVLS fans in high humidity areas will reduce the growth of mildew, mould and bacteria which may occur in such environments. Fan installation usually comprises assembly and suspension of the fans from existing roof steelwork and installation of the required electrical supply and fan control module. A typical basketball stadium with perimeter seating would only require 2 HVLS fans.
For use in winter, fans are fitted with forward and reverse direction speed controls so that hot air may be brought down from the roof area [destratification] to assist with reducing the running costs of existing heating equipment. In buildings with existing air conditioning, HVLS fans will assist in distributing cooled air throughout the building which will allow the air conditioning to be set at a higher temperature, again lowering operating costs.
A typical 5.5 metre HVLS fan will be fitted with a 0.75 kW motor so the running cost will be very low. The fan speed can be adjusted from zero up to maximum, typically about 60 rpm. Subject to the fan diameter, as much as 7430 cubic metres of air will be circulated per minute and the noise level will never be more than 45 dBa.