Maple Sugaring Evaporator

[Perry]

How many panels do I need to run my evaporator on solar? It evaporates a quart of water about every 9 seconds:

http://s6.photobucket.com/albums/y235/perryW/?action=view&current=HPSyrupBoil2Small.mp4

http://s6.photobucket.com/albums/y235/perryW/?action=view&current=SugarhouseSteam.mp4

[Naptown]

With PV here is how to figure it out
To evaporate 1 pound of water takes about 1045 BTU
A quart of water = about 2 pounds
you evaporate about 12 pounds of water a minute or 720 pounds per hour.
to evaporate 720 pounds per hour would take 220 KWH of electricity
Since you would only get at best 80% from an array this would have to be multiplied by 1.25
So the answer would be right about 275 kw


(720 # x 1045) / 3413 = KWH needed +20% system losses = actual system size

If I calculated

[Mike90250]

I'd say use solar thermal evacuated tube collectors, and on a sunny day, they will rock and preheat your sap up to 200F. You may find a vendor who has a way to use a oil base fluid, and get up above boiling, but Solar PV will need a couple acres of collectors to do the job.

[Naptown]

Actually just a little over a half an acre fro PV

As far as evac tubes goes it wouldn't be hard to substitute a higher operating transfer fluid the issue is more what the heat pipes will withstand over time. ET's can reach very high temps
To calculate that you could take the category d OG100 rating divide by the average daily insolation in hours to come up with an hourly output correct for atmosphere's and losses in heat transfer and come up with a number.

example
A collector produces 24k BTU per day for a standard solar day of say 4 hours
so it produces 6000 btu per hour at 90 degrees C above ambient which let's say is 10 degrees
So we are getting 6000 Btu of heat per hour less losses of say 20% so we net out at 4800 btu per hour
so to get 2 pounds every 9 seconds to evaporate would equal 72 per minute x 60 = 4320 pounds of water per hour x1045 btu's per pound =4,514,400 btu's per hour needed / 4800 = 940 collectors.

[peakbagger]

A reverse osmosis unit would be a far better investment than solar even would. The Brown Company research lab in Berlin reportedly did some experiments evaporating maple sugar with high tech equipment many years ago. They could get the sap to the final moisture content, but the syrup didnt taste like maple. Apparently the boiling in open pans caramelizes the sugars giving it the distinctive maple taste. Since they did the evaporation in a closed vessel (probably by vaccum distillation?), the sugar never caramelized.

[Naptown]

If you don't end up with maple syrup that tastes like something other than sap what's the point and would be a poor investment.