An air handler, or air handling unit (often abbreviated to AHU), is a device used to condition and circulate air. Usually, an air handler is a large metal box containing a blower, heating and/or cooling elements filter racks or chambers, sound attenuators, and dampers. Air handlers usually connect to ductwork that distributes the conditioned air through the building, and returns it to the AHU.
Air handlers typically employ a large squirrel cage blower called AHU fan driven by an AC induction electric motor to move the air. The AHU fan may operate at a single speed, or driven by a Variable Frequency Drive to allow a wide range of air flow rates. Flow rate may also be controlled by inlet vanes or outlet dampers on the AHU fan. Some residential air handlers (central 'furnaces' or 'air conditioners') use a brushless DC electric motor that has variable speed capabilities.
In large commercial air handling units, multiple AHU fan may be present, typically placed at the end of the AHU and the beginning of the supply ductwork.
Most of all these AHU fans are made of metal which suffers from the following problems:
1. Corrosion of the AHU fan blade with consequent reduction in the fan performance over a period of time.
2. The fan noise level is increased due to reduction in the surface finish of AHU fan.
3. Difficulty in the manufacturing process causing variation in the AHU fan blades profile.
4. Overall weight of AHU fan assembly is increased which reduces the life of mechanical drive system.
5. High power consumption of metallic AHU fans compared to FRP fans resulting in appreciable energy loses.
6. Difficulty in metallic AHU fan handling and maintenance.
Introduction of fiber glass composite material and ease of processing helped in designing AHU fans to adopt more efficient profiles with optimum distribution of AHU fan blade chord and twist, which are difficult to generate with metallic material. Owing to this fact hollow bladed FRP fans are being rapidly adopted for AHU fan applications.
AHU fans are common product and are used in all types of industries:
AHU fans for operation theatres.
AHU fans for dharma units.
AHU fans for clean room applications.
AHU fans for software industries.
AHU fans for IT industry.
AHU fans for multiplex cinemas.
AHU fans for corporate offices.
AHU fans for switch rooms and many more.