GCTV Ep#13 Sunflower Cooling
Presenter: Philip Burrill - QLD Dept Agriculture, Fisheries and Forestry
To achieve safe storage of sunflowers one of the key storage management choices is including
aeration.
Why aeration?
If we can reduce the grain temperature or seed temperature in storage we make it much
harder for those insect pests that may want to breed in there to actually multiple.
So many cases we end up with no storage pests by reducing that grain temperature.
The other thing we are looking for is creating a uniform moisture content throughout the
whole bulk of that storage.
Growers are aware that there is quite a variety of things in storage, trash, fines and different
moisture content seed as we fill that silo.
So gaining uniformity ensures that we do not end up with mould patches or hot spots in
the storage.
So what are we look for from the equipment with aeration?
We are aiming to actually have fans that achieve two to four litres of air per second per tonne
in storage.
This gets the appropriate airflow to cool that grain.
We are also making sure the ducting is not going to be a hygiene problem so it is easy
to clean and yet still provides a good passage of airflow through the silo.
And lastly the venting on top of the silo, we are looking to prevent obviously rain or
storms from bringing moisture into the storage and at the same time not restrict that airflow
coming out through that aeration cooling.
So how should we be operating these fans on our seed storage?
What we are looking for, for reliable fan operation is an automatic controller.
And that automatic controller goes through three clear phases.
Firstly as soon as the sunflower seed has covered the ducting we are looking to start
up the fans on manual or continuous.
And we are looking for anywhere between three and five days of continuous run of those fans,
twenty-four hours a day.
This pushes the first cooling front all the way through the silo.
The next phase that the automatic controller would switch across to is rapid or purge and
this obtains the coolest nine to twelve hours of each day so often it is running through
the night.
This pushes the second cooling front through the silo.
Finally and this is where the auto controllers really shine, is where they select from ambient
air the best quality air through a month usually resulting in selecting pretty close to about
a hundred hours a month.
So air that is cool, but not in excess in terms of relative humidity.
What sorts of results can we expect with aeration in sunflower seed storage?
In recent experiments we stored sunflower seed that was below nine percent moisture
content.
This was under normal aeration cooling using an automatic controller.
It was in a silo that held sixty-five tonnes.
The storage temperature of that sunflower seed in the initial hours and first day was
over thirty-five degrees Celsius.
This potentially could damage oil quality and certainly is favourable to insect pest
development.
Within two days of running the aeration system we had that reduced to 25 degrees Celsius
so a drop of ten degrees.
Within the next four weeks we saw that temperature drop to less than twenty degrees Celsius and
finally after six weeks below fifteen degrees Celsius.
So here we are seeing aeration has a very valuable role in safe reliable storage.
So you can see the real benefits of utilising aeration when storing sunflower seed.
For more information go to stored grain dot com dot au.
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