Australian Frost Fans: quiet, fuel efficient, with superior coverage area

Written by   Australian Frost Fans

Australian Frost Fans is the sister business to New Zealand Frost Fans, which manufactures the FrostBoss™ range of frost fans.
The FrostBoss range includes 2, 3, 4 and 5-blade models. With FrostBoss machines you do not have to compromise—machines with more blades are more fuel efficient, quieter and have better coverage. The FrostBoss C49 has consequently become the best-selling frost fan in Australia and New Zealand.

Quietest machine available
For situations where there are close neighbours, the FrostBoss C59 (5-blade) model is the quietest machine available on the market and can be as close as 180 metres, whilst producing the most commonly required maximum noise criteria of 55dB (LAeq) at standard operating speeds.
Why is the FrostBoss C49 4-bladed fan better than a conventional 2-blade?
The FrostBoss C49 was developed with help from former Team New Zealand aerodynamics research engineer, Richard Karn, to optimize noise reduction by using a greater blade working area and slower rotational speed than a 2-blade fan.
In addition, the much higher blade passage frequency of the 4-blade fan means the noise signature no longer has a low frequency beating sound, similar to an Iroquois helicopter.
The conventional two bladed design has minimal pitch in the inboard half of the blade. This means the outboard end of the blade is doing all the work and the inboard end is doing very little work. This creates a large variation in wind speed across the length of the blade and creates considerable mixing of the high-speed wind at the tips of the blade with the low speed wind in the middle of the fan.
This mixing process is very turbulent and absorbs a lot of energy from the high-speed wind at the tips. This energy has come from the engine and is wasted making turbulence and noise, not wind speed.
The C49 blade is designed to have the correct aerodynamic pitch all the way from the tip to the root of the blade. This means every section of the blade is angled correctly to produce the same wind speed; from the tip to the root. This produces a uniform wind speed across the whole fan blade—so no turbulent mixing. The result is a uniform tube of wind speed from the fan disc, where all the energy is used to produce wind speed not turbulence.
Blade design evolution
The 4-blade design has evolved considerably in the 12 years it has been on the market.
The blades are now manufactured from high-tech composites using resin transfer moulding (RTM). These blades are incredibly strong.
Upgrade or replace?
Australian Frost Fans install new FrostBoss machines. They also regularly upgrade existing wind machines with a FrostBoss C49 4-blade set, so you can benefit from improved performance without the cost of a whole new machine.
Noise regulations
Some local council noise regulations now require 2-blade fans to be run well below their optimum operating speed to comply.
This in turn means the coverage of the fan is significantly reduced. Existing 2-blade frost fans can be upgraded with FrostBoss C49 blades to meet the new noise regulations, without compromising coverage.
Upgrade options include:
•New C49 composite 4-blade system including new blade hub.
•FrostBoss auto start/stop control system. This feature allows the machine to start, warm up, throttle up and down, cool down and stop, based on adjustable pre-set temperatures, with wireless temperature sensors.
•An anemometer, which acts as a safety/efficiency feature by preventing the machine from running in wind speeds over 8 km/h.
•Remote monitoring, providing access to real-time monitoring of fans via the internet, together with text alarms and historical data and graphs on temperature, run-hours and machine performance.
After-sales service
Together with its sister business, New Zealand Frost Fans, Australian Frost Fans regularly services more than 2000 machines across NZ and Australia using specialist equipment and custom-built bucket trucks. This includes most makes and models, not just FrostBoss.
Australian Frost Fans has service centres in Gawler, Cobram, Naracoorte, Irymple and Munduberra. They are specialists—frost fans is all they do. You’ll be dealing with people who understand the industry having spent most, if not all, their working lives around frost fans.
Australian Frost Fans are happy to provide advice, including suggested fan layouts for your orchard or vineyard.
They handle the whole process from consent application (where required) to site preparation and foundations, installation and servicing.

Ben Daking phone +61 4 4811 1384 or
1800 797 629
email This email address is being protected from spambots. You need JavaScript enabled to view it.
For more information, including customer testimonials, visit

See this article in Tree Fruit September 2018