Aeration at night

[hobbyfrmr]

Last night I downloaded a phsychrometric
calculator. I do not totally grasp the concept, and
can't find a clear graph to study. Last night was -
25c with 62% RH. The inlet part of the calculator
only went down to -18c and I put in 62%RH. The
dew point was -23C. I plugged the outlet side of
the calculator -12%C and 62% RH. The dew point
was -18C. On my 3100 bushel bin my fans put out
3500cfm. This gave me a result of -5.8 lbs/hour,
the difference in the weight of water vapor from
the inlet to the outlet. This looks favourable for
actually drying grain in the cold of winter just with
aeration. Is this a correct interpretation?
The reason I ask is, that, when I was a young 19
yr old farmer an old neighbor told me that this
would work if it was below -20Celcius. His
scientific theory was "common sense". I would be
"freeze drying" the grain, similar to frostbite on the
face and also to think about all the farm women
who would hang the laundry outside even in the
winter to remove moisture from clothes.
Of course I dismissed him as a crazy old man and
figured he was just too cheap to burn some fossil
fuels right after harvest. Every winter when it does
get very cold I run my aeration fans to
freeze/stabilize the grain and always thought
about that conversation. Of course I have always
been too lazy to pull a frozen load out and
measure moisture. I usually turn the fans in May
for a week thinking that is what was doing the
drying. This is a great topic. The phsychrometric
graph should be able to confirm. I will try to find a
more legible one. Any more input would be
appreciated.

[ColevilleH2S]

Can you give us the link to the download?

[freewheat]

in the late, wet fall of 2009, I
combined canola at 14% moisture. The
time of combining was around 5 - 10
degrees C. In mid November, the miracle
fall, I call it...

I put some in 7000 bushel flat bottom
bins, and turned on the fans once it was
colder, in a week or two...I checked the
bin regularly, and blew air 24-7 when it
was below zero, just to freeze the
grain, and hence keep it from heating
until such time as it would be shipped
and dryed. Well, one thing led to
another, and delivery on my contracts
got delayed until june. Upon unloading
the bins, the average moisture was below
9.5, with a small portion of the first
load out being about 10.6. The
temperature of the grain was COLD! Very
cold. I was cold in the bin shovelling
it out. I was as amazed as my neighbors
who were present, that the grain had
actually dried this much. I have kept
canola at 14 before, with no air, for
many months, provided it was combined at
below zero temps, and put in small bins.
This is why I had little concern that it
would spoil, but I never expected that
level of cheap drying. Upon shipment, I
had arranged for drying, and never
needed to dry a single bushel...

I don't think because of this I will be
turning o fans at night when it is not
belw zero though. The nights here are so
bloody wet, it does not sit in my head
right. I will not hesitate to store damp
canola, if it is frozen air you are
dealing with..

[oneoff]

This is a great topic for discussion; but I would suggest not getting carried away by overlooking any factor which would in practice reduce the idea to impracticality.
There are energy costs just running fans. The heat produced by the electric motors and the compressing of the air is a part of the equation.
I've never thoght much about freeze drying; but can relate to freezer burn on loaves of bread (and meat products etc.) in a deep freeze. It is evident that cold can form ice crystals outside products; including potentially grain. But how are you going to actually remove those ice crystals in a cost effective manner. And when there is ice fog and 100% relative humidity; if the grain is below that same outside temperature then it would seem that you will be adding moisture. If the grain is warmer than the outside temperature there will be times that "condenstion" will tend to form. Its going to be a balancing act amongst a lot of factors; and probably needs electronic controls and sensors; but first there must be an understanding of how the factors are related.
Remember cold fusion sounded like a very good idea. We are still fine tuning perpetual motion and its not many years since a lot of people spent money on magnetic seed treaters.
Its an interesting idea; but don't rely on it being the complete answer.

[hobbyfrmr]

Coleville, it was an iPad application called Quest
calculator. I found a good weblink here.

http://edis.ifas.ufl.edu/ae406

[ColevilleH2S]

Thanks for the address.

[DogPatch]

One uses aeration for 2 reasons..... to dry down tough grain, and secondly to cool off dry but hot grain. I do agree that using aeration at night to cool off grain that was combined on a hot day, but I don't think I would ever dare to shut a fan off on tough grain.

The grain ahead of the drying front that is created as the moisture moves up through the grain will be considerably higher than a safe storage moisture. Some fall days the daytime temperature can be less than freezing. If that front were to freeze..... look out. Perfect store for heating, bugs, etc, and if it freezes to the bin walls, that's a recipe for disaster when you try to pull out grain. Especially on the cheaper model grain bins.

[bigsteve]

P.A.M.I. lets hope has done the research on this concept? If not they certainly should.

[Burbert]

Run the fans 24 Hrs. 7 days a week fer
however long yous kin afford it.
Sometimes aeration works great, sometimes
it don't . Usually kin keep grain from
heating, but sometimes it doesn't dry to
great, up towards the toppa the bin. Run
durin cold winter, then run in Spring some
ta be on the safe side. THIS IS A VERY
INTERESTING DISCUSSION THOUGH, TA SAY THE
LEAST!!!

[DogPatch]

Its nice to see something intelligent from you B...... Keep it up.

[JACKFLASH]

I was told once buy a very knowledgeable grain buyer to keep the fans running no matter what. Unless its raining heavy or snowing.

[Burbert]

A VERY KNOWLEDGABLE GRAIN BUYER? Which
chisler company did he work fer. I was
once told by a maltster ta try and supply
more consistent grain ts their company.
Probably the same guy!!!!!! I QUIT
SELLING TO THOSE CHISLERS immediately...

[TOM4CWB]

Burbert,

Great to see you learned to "vote with your truck"!

There is truly hope for your marketing skills!!!

Cheers!

[Burbert]

Lets see, since I've quit sellin to that
chisler, and I hate the other chisler
company and the other 2 multis are way to
far away. Guess I'll have to sell to the
funnnn feeder down the road. Butt I
forgot he scr#wed me last time too. Buy a
grain stove and burn the stuff, and cook
some an eat it 2!!!! Votin wit a truck is
a beach at times, however!!!!!!!