Solar Parabolic Trough Charcoal Oven

[Nitack]

It will work, it's just a matter of tweaking the system until we get the right temperature and heat spread. What size lenses did you order and where did you order them from?

 

For preliminary testing I ordered two 70"^2 lenses from <a href="http://kensolar.com/tek9.asp?pg=products&specific=jnnqiml8" target=blank>Ken Solar</a>. I was not going to spend too much on a huge lens before I do my testing. Once the testing is done and a larger lens is needed I am hoping to find one on either ebay or at a junkyard from a rear projection TV. If I can not find one either way then I shell out and go through Edmund Optics. But I think I should be able to find one on ebay easy enough, there are normally a few listed.

[Turtle]

For preliminary testing I ordered two 70"^2 lenses from <a href="http://kensolar.com/tek9.asp?pg=products&specific=jnnqiml8" target=blank>Ken Solar</a>. I was not going to spend too much on a huge lens before I do my testing. Once the testing is done and a larger lens is needed I am hoping to find one on either ebay or at a junkyard from a rear projection TV. If I can not find one either way then I shell out and go through Edmund Optics. But I think I should be able to find one on ebay easy enough, there are normally a few listed.

 

That's the ticket!! Put some fire in the hole & see what's what. ;) Overhead projectors have a Fresnel in them too; school systems sometimes sell off old equipment.

 

...I could be wrong, but if it is hooked up to a car battery, then everything should be ok. In a car, the battery fires the spark plug which turns the engine. Once the engine is going, it supplies the alternator with power, which charges the battery. I think I have that right...Turtle, can you confirm or deny please?

I'm certainly on shaky ground when talking about cars and especially electricity. Time to do some wiki reading I suppose....

 

Electronic chips & do-hickies aside that we find in the newer cars, once an engine is running the battery can be removed and the alternator powers the spark coil and other electrical systems. The alternator is driven by the engine. When the battery is connected, a voltage regulator senses when the battery is low and sends some of its output to a charging circuit. When the battery is full up, the alternator stops sending juice to the battery.

 

If the idea is to use a solar furnace to make steam to drive an alternator to make electricity,* then batteries are the standard storage method.** Any thing using 12v DC can be operated directly from the battery/alternator setup. If you want standard 120V 60Hz AC (house current) you need a device called an inverter. Widely available in different wattage ratings, they connect to the 12v battery and you plug your cords into outlets on the device.

 

Ok; that's another wrap. :D :)

 

*to avoid the batteries, the alternator current can directly power an electric pump for the sceme we discussed earlier. Other transfer/storage methods include heavy flywheels and electolysizing water to make hydrogen.

 

**the typical battery is 12volt deep-cycle they are rated in amp-hours. storage capacity is increased by adding batteries.

[freeztar]

Electronic chips & do-hickies aside that we find in the newer cars, once an engine is running the battery can be removed and the alternator powers the spark coil and other electrical systems. The alternator is driven by the engine. When the battery is connected, a voltage regulator senses when the battery is low and sends some of its output to a charging circuit. When the battery is full up, the alternator stops sending juice to the battery.

 

Thanks for that Turtl. :D

 

*to avoid the batteries, the alternator current can directly power an electric pump for the sceme we discussed earlier. Other transfer/storage methods include heavy flywheels and electolysizing water to make hydrogen.

 

Speaking of electrolyzing, my friend just stopped by for an hour and he kept talking about electrolysis, funny that I come back to this thread after he leaves and you had mentioned it. :) :D

He spoke of a setup in France that achieved enormous temperatures. So I looked it up and found this.

It can reach 3400 degrees C!! :D :D (he claimed 28,000 degrees F, but I think he meant 2,800 ;))

But of course this is uber expensive (not even considering the storage and transportation costs for H2). :(

My friend went on talking about using the heat to "separate" the atoms in the water molecule and using a low voltage charge (from solar collection/electricity) in the water to unbind the molecules (ie electrolysis).

He admitted that it's not safe for the average Joe, but derided the lack of global participation and awareness of the possible applications.

Anyways, I think I've veered off course enough for now. :D

 

Nitack, check out the first picture from the link. Using mirrors, or heliostats, a relatively enormous amount of energy could be created eh? :)

I checked out the link for the fresnel lens and it looks too good to be true. Only $13 for something that can focus to temps of 3000 degrees F that is also thin and light! ;) I find that claim incredulous, but if it is only 25% of the temps claimed then it is still kickin butt, and usable for charring. I'm awaiting your results and will order some myself if they are, even a quarter, as effective as they claim.

[Turtle]

Thanks for that Turtl. :D

...

Speaking of electrolyzing, my friend just stopped by for an hour and he kept talking about electrolysis, funny that I come back to this thread after he leaves and you had mentioned it. ;) :D

He spoke of a setup in France that achieved enormous temperatures. So I looked it up and found this.

It can reach 3400 degrees C!! :D :D (he claimed 28,000 degrees F, but I think he meant 2,800 ;))

But of course this is uber expensive (not even considering the storage and transportation costs for H2). :(

My friend went on talking about using the heat to "separate" the atoms in the water molecule and using a low voltage charge (from solar collection/electricity) in the water to unbind the molecules (ie electrolysis).

He admitted that it's not safe for the average Joe, but derided the lack of global participation and awareness of the possible applications.

Anyways, I think I've veered off course enough for now. :)

 

Bitte. Not off topic at all. I read the link but saw no mention of electrolysis. No worries. All you need to recover hydrogen is your 12vDC, a tank of water with some salt in it, a collector over the electrode for the hydrogen gas(the negative side I believe), and patience. I sometimes use electrolysis to plate jewelry, & let the gasses bubble off.

 

So, to use a home solar furnace of some design to make steam to power the alternator to use the 12v DC output to electolyze water to collect the hydrogen to burn as fuel, in the house that jack built. :D

 

Giddyup. :)

[freeztar]

Bitte. Not off topic at all. I read the link but saw no mention of electrolysis. No worries.

 

My bad, it was on a different page.

The energy carriers we study are solar electricity from concentrating systems, and solar fuels, particulary hydrogen, from solar process heat.

All you need to recover hydrogen is your 12vDC, a tank of water with some salt in it, a collector over the electrode for the hydrogen gas(the negative side I believe), and patience.

 

Indeed, but why not speed up the process eh? ;)

 

I sometimes use electrolysis to plate jewelry, & let the gasses bubble off.

 

Please tell! How do you use electrolysis for plating?

 

So, to use a home solar furnace of some design to make steam to power the alternator to use the 12v DC output to electolyze water to collect the hydrogen to burn as fuel, in the house that jack built. :D

Giddyup. :)

 

And it's turtles all the way down. ;)

[Nitack]

Well my end thought was to power both the house and a hydrogen plant via these cheap solar generators. Check out this slashdot story;

Slashdot | Solar Power Eliminates Utility Bills in U.S. Home

The guy uses 1000'^2 of solar cells... The yahoo story it linked too is expired, but I believe the estimates on this prototype house was $100k, and the bulk of that was solar panels.

 

Generating the electricity using these generators we are basically designing seems to be the easy part. Standard technology, mass produced parts are already available, and we seem to have figured out the heating issue. It also just dawned on me that we need a relatively small chamber for water/whatever heating as for these purposes we are no longer trying to heat a large area for charcoal production. Also we can use a multistage heating process so that the chamber itself does not have to do all the heating which may slow us down. Kind of like the copper coil discussed.

 

The hard part, and way out of my field of understanding is the condensing of the hydrogen into tanks. From there you just feed the gas into the generator. I have a concept in my head about the way the whole thing can be set up. Perhaps I will put my viseo skills to work and create a diagram for the solar generator and the system in general. It all seems to work in my head...

[DougF]

This sound fairly feasible I wish I could see a diagram to wrap my mind around,

shame the link expired, :doh:

But it sounds like you might be on to something here. :)

[Nitack]

Now that I am delving deeper into this I am wondering if it is even worthwhile to think about such a complex system. The electrical generation and hydrogen production is easy enough, but throw in sun tracking equipment, compressor for the hydrogen, tanks, and a hydrogen generator and this may start getting just as expensive as a whole house system of PV pannels. Basically the only difference between our system and the ones that already exist is the solar power generation method. The cost of PV panels being what we are trying to avoid.

 

Gonna run some numbers to see what a system like this would cost. Rough shopping list to price out:

• piping - given high heat, metal required for most of it, copper ideal but expensive
  
• used car water pump - wrecking yard
  
• used car alternator - maybe more than one of these to increase output
  
• car battery - just to provide initial charge to alternators
  
• Solar tracking components to follow the sun.
  
• compressor - needs to be able to compress hydrogen from holding area into presurized tanks
  
• hydrogen generator
  

 

These are the basic components, although we might have to add some more items for grid tie ins and such. Perhaps this is just pie in the sky type thinking, but if it is affordable I might just try this.

[DougF]

You got me thinking (a good thing) and looking around and i found this site Brewing hydrogen

Brewing hydrogen : HERO

Hydrogen is usually captured through hydrolysis' date=' by splitting water into its component elements – an energy-intensive process. Now, however, bioscientists at the University of Birmingham have demonstrated a radical new approach that recycles industrial waste, and could prove economically viable for large-scale production.

<-->

the researchers showed how bacteria fed on high-sugar waste from the confectionery industry produce quantities of hydrogen gas, which can then be used to generate pollution-free electricity.[/Quote']

This is a new technology to me but thought you might want to hear about it (if you didn't already now).

[Turtle]

Now that I am delving deeper into this I am wondering if it is even worthwhile to think about such a complex system. The electrical generation and hydrogen production is easy enough, but throw in sun tracking equipment, compressor for the hydrogen, tanks, and a hydrogen generator and this may start getting just as expensive as a whole house system of PV pannels. Basically the only difference between our system and the ones that already exist is the solar power generation method. The cost of PV panels being what we are trying to avoid.

 

Agreed. And to add insult to the injury, 'they' have been saying for years that the cost of PV panels is going to go down and they haven't. :rant:I have a single 15watt panel that I paid $130 for on sale 4 years ago; last time i looked they're going for $150 still. :D

 

On the plus side of PV panels, you don't need to track the Sun and they operate even on cloudy days. I don't think the solar furnaces will work well if at all without direct Sun. One option with the PV's is to start with a few and add panels as you can afford them until you reach a self-sufficient level. Many utilities buy excess power from people with panels; professional electricians will wire the proper equipment at your house into the grid which automatically (and Safely) detect usage and switch the system appropriately.

 

Please tell! How do you use electrolysis for plating?

I wrote a short description & put it in the Art Gallery thread, post#128. :)

[Nitack]

hey, the idea will still work for coal production, and that is the immediate purpose. Even if I can't produce my own power with it, I can still pull CO2 out of the air for the power I do use!

[Turtle]

hey, the idea will still work for coal production, and that is the immediate purpose. Even if I can't produce my own power with it, I can still pull CO2 out of the air for the power I do use!

 

Absolutely. :D All the brainstorming aside, it's a 'just do it' attitude that carries the day. On a last note, if you haven't settled on a container you might consider one of those cast-iron dutch ovens. Durable, takes the heat, has handles on lid & pot, and the weight of the lid will act as a relief valve.

 

That's a wrap. :)

[Nitack]

So I got tired of waiting for my fresnel lens from Ken Solar - Solar panels, portable solar powered generators, wind turbines and more!. I did a little searching and guess what I found... Office Depot® Brand Full-Page 8 1/2" x 11" Magnifier at Office Depot.

 

Yep, Office Depot sells a fresnel lens, although 8.5x11 is as big as they get. And at 6:30pm I was able to focus enough energy to instantly light paper on fire. Consider it was so late in the day, and I mean visibly getting darker, at around 11 or 12, should be more than enough energy with a full sized lens to power our charcoal production!

 

Funny thing, I got home and the fresnel was waiting for me. Ken is fast, definitely shopping with him again. I ordered my lens day before last.

[Nitack]

Absolutely. :D All the brainstorming aside, it's a 'just do it' attitude that carries the day. On a last note, if you haven't settled on a container you might consider one of those cast-iron dutch ovens. Durable, takes the heat, has handles on lid & pot, and the weight of the lid will act as a relief valve.

 

That's a wrap. :)

 

Turtle the dutch oven is PERFECT, at least for test purposes. Not going to be big enough for my ultimate purpose.

[freeztar]

So I got tired of waiting for my fresnel lens from Ken Solar - Solar panels, portable solar powered generators, wind turbines and more!. I did a little searching and guess what I found... Office Depot® Brand Full-Page 8 1/2" x 11" Magnifier at Office Depot.

 

Yep, Office Depot sells a fresnel lens, although 8.5x11 is as big as they get. And at 6:30pm I was able to focus enough energy to instantly light paper on fire. Consider it was so late in the day, and I mean visibly getting darker, at around 11 or 12, should be more than enough energy with a full sized lens to power our charcoal production!

 

Funny thing, I got home and the fresnel was waiting for me. Ken is fast, definitely shopping with him again. I ordered my lens day before last.

 

How does the lens from Ken's solar compare to the one from office depot? Are they of the same calibre?

 

I ordered a bunch of sheet magnifiers off of ebay for my own experimentation. Hopefully they are of decent quality. We'll see...

[Nitack]

I have not pulled out a ruler or anything, but the sheets from Kens Solar look like they have MANY more ridges per inch. If my understanding of the geometry is correct, more ridges mean more powerful/higher magnification.

 

The office depot stuff will burn, but I don't think it will have the same intensity. Unfortunately they do not have the same surface area so a test of temperature at focal point would not be fair.

 

Well, it could be fair, but would require way too much math for me. measure temp at focal point and then divide by area squared in order to get heat output per square inch.

[freeztar]

Unfortunately they do not have the same surface area so a test of temperature at focal point would not be fair.

 

Well, it could be fair, but would require way too much math for me. measure temp at focal point and then divide by area squared in order to get heat output per square inch.

 

If you produce the numbers, I'll do the math.

 

My guess is that the surface area to temperature ratio will be exponential rather than linear (perhaps even following a Fibonacci sequence:scratchchin:).

 

I can't wait to get my sheet magnifiers. I'm hoping to be able to use a few of them in tandem (or maybe parrallel) to get some significant temps. We will see...:shrug: