Solar Ceiling Fans Australia Case Study Greenhouse Ventilation in South Australia

We are fortunate to have a number of solar ceiling fan customers in Australia and a recent installation required some creative problem solving.

A Vari-Cyclone 3 blade ceiling fan was installed in a greenhouse in South Australia to provide cooling ventilation during the day for workers.  The installation included a 40 watt 12 volt panel and Speed Control, which is a linear current booster which increases the voltage to the fan to make it run at top speed.

The initial installation was not performing as intended.  A comment from one of the participants down under was that the fan would not move enough air to "blow the skin off the rice pudding."  That colloquialism is not one common here in the USA but certainly got the idea across that something was wrong with the installation.  My response was that  the Vari-Cyclone should blow the rice pudding and bowl away, plus the skin.

Photos of the initial installation show the fan blades correctly oriented, the Speed Control mounted in a weatherproof enclosure, the panel mounted at a good angle facing due north, and a view of the panel through the greenhouse covering.

We went through all the troubleshooting steps regarding wire size, polarity, fan blade rotation, proper wiring of the speed control without any improvement and tested the fan with a battery as an alternative to power direct from the panel.

The manufacturer's engineering department got involved to assist and we came up with a whole list of to do items.  I added my idea that maybe the fan was mounted too close to the ceiling and not close enough to the floor to create optimum air flow.

The installation was modified to drop the fan closer to the floor and provide more head space above to create better air collection by the fan blades.

The response that came from down under:

Ron, I have some good news and some bad news. The good news that is after some re-fitting the fan is working as it should and producing a nice amount of air flow. The bad news is that not only did it blow away the rice pudding bowl it also blew my dad to the ground,  please see attached photo.

After reading your email the thing that grabbed us the most is at what height we  suspended the fan from, this being the distance from the ceiling and also distance from the ground. When we initially installed the fan there was less that 2 feet above the fan blades to plastic greenhouse cover, and even less at the ends of the blades because the roof is arched. We had a thought that maybe the fan couldn't draw enough air due to the limited air space above.

The other factor was that we initially mounted our fan around 9.5 feet from the ground, because it is in an outdoor environment perhaps it was too far for the air to reach the ground.  We added a cross brace from the structure of the greenhouse so that they fan is now about 8 feet from the ground.

After doing these modifications the rice pudding, bowl and dad are all blown away.

We are quite happy with the product and is performing just how you said it would. It took a little in the end to work out but now we have it sorted. Thanks for all your support, wishing you a very Merry Christmas and a Happy New Year.