Firebox/arch science and Solar steam Power

[GOwin]

Has anyone else played with the idea of using Solar Power for fueling their arches? I've seen this thread (http://mapletrader.com/community/showthread.php?t=6530&highlight=solar+power) that mentions a woman in Berlin, NH being featured in a newspaper but it is scant with details.

You see, I've recently seen on TV a temple in India which uses "Solar Steam Cookers" and "Scheffler Community Kitchens" powered by Scheffler Reflectors (http://solarcooking.wikia.com/wiki/Scheffler_Community_Kitchen) that harness the power of the sun to generate steam.

I am particularly interested in the science/physics principles behind firebox design. With conventional fue arches, the fuel is burned under the front portion of the pan. The back of the firebox would have a bottom that slopes upward toward the rear next to the outlet for the chimney. Hot gases from the fire travel under the pan, heat is transferred to the sap in the pan. The gasses cool. The upward sloping firebox concentrates the cooler gasses next to the pan and thereby maintains a higher temperature per unit of surface.

What if you replace your current fuel (firewood/oil/etc.) with Scheffler dishes? Do you think there's a need to redesign the firebox?

The above-mentioned firebox design maximizes the heat from an expensive fuel source? Since solar power is almost free (or cheap), do you think it's better to heat the whole underside of the pan directly instead?

Looking forward to hearing from you.

[PerryW]

My 3x10 evaporator burns a cord of softwood in 7 hours of boiling and my yield is about 15 gallons of syrup. That's about as much wood as I use to heat my house for an entire month. You would have to have a serious solar power setup to produce that much evaporation. I would also worry about weather conditions like we have right now; a pretty decent extended sap run during a rainy period with not even a glimpse of the sun.

[Stickey]

Convert the rain to hydrogen....viola!

[GOwin]

Hello Perry.

If you've seen the links I've placed in the original posted (and went any further), it will show you seriousness of this solar power source is. For example a 16m2 dish has a focal temperature of 700-900°C, which can burn exposed wood in several seconds. The large dishes ( > 10m2) are meant for steam generation using solar power, while those smaller than this is meant for indirect-heating (using a secondary reflector)

A 50m2 design is being made for a crematorium :o

PS
I already edited the thread title from Firefox to Firebox but it doesn't seem to be updating the index list... anyway ....

[3rdgen.maple]

I think Perry was being serious How are you gonna make solar power without a sunshine? I bet I had 2 maybe 3 at most sunny days all sugar season this year. It is hard enough relying on mother nature to give us sap now throw in the equation of when we can boil based on when the sun shines and what about the guys who are night boilers that have day jobs? I not trying to bash your idea in anyway at all just throwing things out there to think about.

[RileySugarbush]

Direct application of the solar energy would require directing the light at the bottom of the pans which seems troublesome. You need an intermediate working fluid to transfer the heat.


If you have the sun and space ( which I bet you do, considering where you probably are) the best way to do this would probably be to generate steam and circulate through pipes in the sap. I have heard of others using steam as the heating medium and in those cases the steam is just created in other ways.

Did you ever do the experiment connecting tubing directly to the palm spathe and using vacuum or gravity to minimize the need for climbing the trees?

[GOwin]

Oh, I'm sorry. I forgot to remind you that I don't tap maples. I live in the tropics and tap coconuts instead. :cool: We've got abundant sunlight here, having a wet season lasting about 3 months - and even during the wet season, sunny days still happen.

My question about solar-powered evaporator and the arch design was not specific to maple sugaring. But considering that maple people have more experience in this area (flat pan evaporators and arches), I am posting this question in this forum instead.

Check out my Tropical Sugaring thread for more information about what I do. :)

[michelle32]

My son goes to Morrisville state college NY and they are working on alternative fuel fired evaporaters. Solar and wind I believe are part of this. Along with gasafication and others. There not talking much I believe there trying to get a patent on something so I'm told.

[Clan Delaney]

I already edited the thread title from Firefox to Firebox but it doesn't seem to be updating the index list... anyway ....

Took care of that for ya.

[GOwin]

@michelle32
The Scheffler Reflectors are open source. The inventor gives you the permission to freely modify it to your own needs.

@RileySugarbush

The following are two common application of the Scheffler Reflectors:
A system using two reflectors, with the second reflector directing the light under a pot:
http://www.solare-bruecke.org/English/scheffler_e-Dateien/grafik07.gif

A solar array of Reflectors for generating steam, which is then piped in to a boiler:
http://wka3.de/bildergalerie/bildergalerie1/bildergalerie/gross/Unbenannt-37.jpg

Steam for cooking:
http://wka3.de/bildergalerie/bildergalerie1/bildergalerie/gross/Unbenannt-41.jpg


@clan
Thanks!

[Clan Delaney]

GOwin,

Now that I understand that the sap you're starting with is 20% sugar.... I think a solar evaporator would easily do the job for you. On average, our sap is 2%. That's a LOT of water to evaporate!

I think you could make something that took the concentrated sunlight beam, and then spread it out again over the underside of a flat pan. Though, a VERY large wok might do better.

[GOwin]

20% is a very good number, but seldom seen. Average sugar content is about 13%.

A wok, which is what is widely used here would be easy enough but I'm wondering if I could take advantage of the larger surface areas of flat pans.

It still takes 3-4 hours to boil off the water. (I know I shouldn't complain knowing how some of you boil for like 8-10 hours a day.)

So again, using a dual-reflector system, a pot/wok is easy enough. But since I'm interested in experimenting with flat pan evaporators and baffles. Maybe, just maybe, I can cut down processing time to like 2 hours. :cool:

Let me get rid of some thoughts I got in my head right now: steam is gas. It is hot gas that gets moved from the front end of the firebox and out to the flue.

So, I *guess* a firebox will also work if steam is directed in the front side of the arch. But, if it's feasible, would directing the concentrated sunbeam under the whole underside of the pan work just as well?

[michelle32]

I'm not sure what there working on. My son was told to tell no one what it is. So I'm not sure just what it is. I do know he mearsured the fire box on my rig for the professor. Other than that nothing.

[Bucket Head]

What would the neighbors think with rows of reflectors like that in the side yard?

I'm thinking the town Codes Officer would be stopping by for a visit.

Steve

[brookledge]

There are a few producers who use pressurized steam to boil their sap. The pan is just a large flat pan with a lot of steam pipes that run the length of the pan. I'm wondering if you could use the solar power to generate steam and then boil the coconut sap. As it was already said New England is not a great place to use solar, average of only 25% sunlight per day per year.
And in our case you need to boil when you get the sap not when you have to wait for the sun. I'd say the fact that we have such a short amount of daylight during sugarin that most of us are boiling at night anyways.
Keith

[Brent]

I do at least half my boiling, like right now, after sunset.

Even on a good day you'd need acres of panels/mirrors.

Burn wood. It is carbon that is already above ground and in the environment. Leave the oil underground. It's the oil and natural gas that has been underground for 10 million years that we're bringing back up into the environment.
Besides, if we don't burn it, it will just fall down and die and release all the carbon in the natural cycle.

As noted above, I heat my house with wood almost exclusively. The evaporator eats the same amount of wood in a season as it takes to heat the house for a year.

[GOwin]

They probably think you're trying to talk to alien life.


What would the neighbors think with rows of reflectors like that in the side yard?

I'm thinking the town Codes Officer would be stopping by for a visit.

Steve

Now, that's interesting! Got any more info about these?

Thanks to you, I found an interesting article: Use of High Pressure Steam in the Production of Maple Products (http://www.omafra.gov.on.ca/english/crops/facts/03-027.htm)

Would love to know more about this.


There are a few producers who use pressurized steam to boil their sap. The pan is just a large flat pan with a lot of steam pipes that run the length of the pan. I'm wondering if you could use the solar power to generate steam and then boil the coconut sap. As it was already said New England is not a great place to use solar, average of only 25% sunlight per day per year.
And in our case you need to boil when you get the sap not when you have to wait for the sun. I'd say the fact that we have such a short amount of daylight during sugarin that most of us are boiling at night anyways.
Keith

Yes, the power generated depends a lot of the amount of sunlight you get and the number of reflectors - or the reflector size. I think they've tested systems that can generate 12 bars of steam.

As for "above ground carbon". Well, the issue is whether it remains trapped (ie trees, wood) or released to the air (ie burned ). Cutting only stops the trees from absorbing new co2, but carbon remains intact in the wood itself.

Right now, it doesn't matter where the source of carbon is (below- or above-ground) but the general state of the environment today is at a fragile tipping point - we're releasing GHG at a rate that's more than natural carbon balancing processes such as photosynthesis and the oceanic reservoir can handle, resulting in global warming. I'd like to do my best to reduce my own carbon footprint.


I do at least half my boiling, like right now, after sunset.

Even on a good day you'd need acres of panels/mirrors.

Burn wood. It is carbon that is already above ground and in the environment. Leave the oil underground. It's the oil and natural gas that has been underground for 10 million years that we're bringing back up into the environment.
Besides, if we don't burn it, it will just fall down and die and release all the carbon in the natural cycle.

As noted above, I heat my house with wood almost exclusively. The evaporator eats the same amount of wood in a season as it takes to heat the house for a year.

[PerryW]

You could always use the solar to generate electrical power and push your meter backwards. Then, use electricity for the RO and an electric powered evaporator.

[GOwin]

That's possible, too.

But an R.O. machine is something that I think I can forego in the immediate term considering the how much sugar content of my sap has.

Besides, though electricity generation from solar power is possible, that will also raise the cost of acquisition of the system. At the moment, what I'm looking for is the feasibility of taking out the firewood as fuel from the evaporation process.


You could always use the solar to generate electrical power and push your meter backwards. Then, use electricity for the RO and an electric powered evaporator.

[brookledge]

Bascom maple makes alot of syrup from one open pan that is boiled with high pressure steam
Here is their web site . I think they are one of the largest producers in New England
http://www.bascommaple.com/index.html
Keith

[PerryW]

Creating a steam boiler sounds complicated, dangerous and expensive. It seems like directing the concentrated solar radiation directly on the bottom of the pans would be the simplest approach.

[GOwin]

I agree with you on this - it appears to be the simplest option. Possibly, a very good starting point.