Magic Macadamias | Roelof van Rooyen goes green with nuts
These days it takes a new breed of farmer to get on top in agriculture and guys like Roelof van Rooyen are changing the industry to a greener landscape.
By Benno Stander

Roelof van Rooyen at the computer that monitors and controls the dryer
Roelof van Rooyen is the managing director and part shareholder of Alkmaar Valley Macadamias which is home to one of the smartest macadamia processing plants in the country. He grew up on a macadamia farm and knows the industry inside out. When he finished school and his studies he decided to go sailing and diving and spent some time exploring and working in Mozambique and Borneo. He obviously had lots of fun but soon realised that, as he puts it, “…wasn’t using much of my brain.”
When he found his way back to South Africa he went on to further his engineering qualification by doing an MBA and returned to his father’s farm afterwards to assist with the exporting part of the business. “Soon I felt like I could do more,” he recalls. “I’ve always loved the macadamia industry but what I was doing wasn’t enough of a challenge. I wanted to be a little more creative and imaginative.”

Macadamia nuts falling off a shoot and onto a conveyor belt that transports it to the dryer
At the end of 2011 Roelof bought a farm at Alkmaar to start his own endeavour and soon realised that although there is lots of available space for planting, the biggest asset of the property was the massive empty factory that used to be a citrus and avocado pack house.
Since he knew the macadamia industry so well he decided to use this pack house to build a macadamia processing facility. But since he also knew what the shortcomings of the current method of processing were, he decided to add a little twist to his system. With the help of investors and field specialists in the area of energy efficient technology, Roelof set off to build a macadamia processing plant like no other.
“The two biggest expenses when running a facility like this are labour and energy consumption in the form of electricity. So from the first concept what we wanted to do was cut down on these factors to lower the running cost. This is when it was decided to turn to greener forms of energy to dry the nuts.”

The final step in the process is sorting the nuts according to size
How it all works
From the time the nuts arrive on trucks at the factory to when it is packaged and shipped, it goes through several processes in different areas of the factory. Moving around tons of nuts can be a lot of work and would require a lot of labour. For this reason it was decided to fully automate the moving of the nuts by using conveyor belts and shoots. This way the nuts go where they need to be when they need to be there and just about the whole transportation system is controlled by computer which minimizes the amount of labour needed. The entire factory is operated by 15 labourers, one controller and one lab technician.
As for saving on electricity, Roelof and his team really came up with an ingenious idea to utilise the Lowveld sun. Normal macadamia processing plants use electrical heaters to heat the air that dries the nuts. These heaters are responsible for most of the electricity usage.
To get the best result they first painted the roof above the drying area black and built an air chamber right under it. The temperature of air under roof varies between 50 and 70‘C during the day but drops quite a lot at night which would have been a problem if they did not come up with the clever idea of building a heat battery.
To build the battery Roelof’s team used 36 000 building blocks with holes right through that were stacked in an insulated room measuring 20m long by 6m wide and 4m high. During the day circulation fans draw heat from under the roof and blows it through the bricks that absorb the heat. The hot air from the roof is also used to dry the nuts during the day and at night air from the heat battery gets used. To dry the nuts they only need between 25 and 40’C so both the roof and the battery supply sufficient heat.
To top off all of these clever plans the factory also has some very nifty computer software that uses pre-set parameters to automatically measure temperature and humidity in the various wind tunnels. It then uses this information to ‘decide’ when to open and close louvers in the wind tunnels. On the computer there is also a visual representation of the factory that shows all the data from all the sensors. The computer can be used to override the automatic process to open and close louvers, put fans on and off or control any other part of the process.
“We have already recorded drastic savings on electricity usage and can’t be happier with how this experimental factory has turned out. Even though we are still fine tuning some aspects of it, the idea is to build more like it in the not so distant future,” says Roelof rather proudly.
Find out more
For more information on the Alkmaar Valley Macadamia factory mail Roelof van Rooyen