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10' sat dish,mirror tiles,want electric,how?

1.6K views 19 replies 12 participants last post by  mightybooboo  
#1 ·
OK,nephew has a ten foot dish.He is applying the little mirror tiles to it.He is making a LOT of heat.

Now....how does he use this heat? What would you do with it,electric,hot water or??

Would like to hear all ideas,hot water,steam or ?? Especially links to products you would use with your ideas would be helpful.

He has a limited budget so keep that in mind too but still want to hear what you think regardless of price.
 
#2 ·
Hot water would be cheaper to build. If he's building alot of heat he may even porduce steam if he doesn't maintain a good flow through it. He may not hve to modify the tracker if he can run a pipe horizontally across it at the focal range.

Elecrtic from it would be harder. He would have to calculate how many times he's increased the suns value and find CPV cells that can at least handle that. He's also going to have to modify the tracker to follow the sun all day.
 
#3 ·
I don't think focusing on a solar cell is a good idea. Cells produce their rated amperage at a certain temperature. As the temperature increases, electrical output goes down. Plus, if it's as hot as I think you might be getting it then the cells might be physically damaged.

I think a far better application would be heating hot water, or maybe a baking oven. I could envision both, maybe on some kind of swinging mount. The light could be focused on a copper coil that water is circulated through to a tank. When you want to cook something you could swing a metal box into position that acts as your oven. To start baking just swing the box out of the light beam, pop in your bread dough, then swing it back in. Thirty minutes later, hot bread!
 
#4 ·
You could change the heat to mechanical power using a Minto Wheel then use the wheel to turn a genny.
 
#5 ·
It will be difficult to generate electricity with though he can produce a lot of heat in excess of 900 degrees F which is more than enough to run a small steam engine however such heat and pressure also becomes quite dangerous .
If he's looking for a way to use the heat its self . a heat exchanging water heater can be made from various scrap parts .
using said heat in the home can be done through radiant floor heating or air exchange .
for a cheap high heat water pump make a backing plate for a automotive water pump .
 
#6 ·
check mother earth news mag. it had a series on mirror reflector but much larger to make steam...used a modified 5 hp engine as a steam engine...not sure of the results...TAB books also had a book devoted to the project with diagrams and modification prints.
 
#8 ·
Might have him take a look at SolarGary's site (www.builditsolar.com). I know he has some info there on concentrated systems. Most of them are for water heating or cooking.
 
#9 ·
There was an article on CNN.com or maybe foxnews.com about a guy who made something like this. His was powerful enough to ignight a wood pole or torch at the focus point.

The easiest way I can think of using that kind of heat would be to use it as a water heater... have to make sure your flow rate was high enough that you didn't just vaporized the water though.

Better would be a steam engine powered generator, but that would also be more complex. The generator would be expensive, and rigging it to be run by the steam engine could be complicated though.
 
#10 ·
there are some federal regulations that make the use of steam engines somewhat difficult . boilers must be inspected yearly pressure tests and such .
theres actually a lot of regulations on steam power that can get you in deep trouble .
 
#11 ·
Went to check out his project.Its currently for water purifying in third world countries,senior engineering project in college.

This is a 1 of 6 sections,Click to enlarge....



flat on ground about 1pm.At the focal point(as out of aim as it is) it burns your hand GOOD in a couple seconds.Might not be perfect but it throws out some serious heat.

It will be on a tracker made with a motor from automatic doors and a couple photo eye cells (whatever they are called).

Good for him,fine project.

I emailed your ideas to him too,thank you.
 
#12 ·
Just for fun I thought I'd plug in a few numbers. If the dish is 10 foot in diameter (3.0 meters), that would give you about 7.07 square meters of collection surface. If the sun produces about 1000 watts per square meter at ground level, and assuming your mirrors cover 95% of the whole surface, that works out to be about 6800 watts of heat energy being focused on the center.

That number might be valuable in trying to determine just how much water you can heat, or how hot you can get whatever it is you want to heat.
Michael
 
#13 ·
He said he was hoping the entire system when finished with water setup would be in the 25% efficient range.If he hit that he would be very pleased

6800 watts,thats amazing!

When he gets the thing done I will be sure to post his results,good bad or ugly.

A little OT,Ive noticed that the small sat dishes get snapped up fast at the thrift store,not the case a while back,couple of years ago.Guess more folks are playing with it?

WAAAAY OT,he's interning at SCE this summer and they are doing a major powerline project coming out of Tahachipi due to the increases in wind power going on out there.:bouncy::clap:
 
#15 ·
#16 ·
This is a great project!

For heat, perhaps filling some black metal drums with a heat retaining material and lining them up on the inside of the house and then focusing the dish so that the heat is reflected directly toward them would work. Kind of like having a huge expanse of south facing glass.

I did hear about a "well-meaning" company that provided a huge reflective dish for the locals to cook their communal meals. They were really excited to use it and it worked great. Unfortunately, when they were finished, they inadvertently aimed it at a grass-roofed building and it burned to the ground...oops...

RVcook
 
#17 ·
Hi,
I do have a section on concentrating solar:
http://www.builditsolar.com/Projects/Concentrating/concentrating.htm

But, I think the best site for hands-on concentrating stuff is on Redrok.com

Duane (who runs Redrok) has talked about satellite dish reflectors made by applying reflectorized Mylar sheet. I believe that he uses grease as the adhesive to hold it in place. It has a life of about 3 years, and grease makes it easy to take off and replace.

I did look into running a steam engine from concentrating solar, and found the efficiency of small steam engines to be very low -- don't remember the exact number. The small steam engines are also expensive, as far as I could tell they are only made in small quantities.

I like the solar concentrating coffee bean roaster :)

Gary
 
#18 ·
Thanks Solar Gary for the mylar purchase links from Red Rock,I couldnt find a mirror quality source at all by googling.

I didnt know they had tested (or are using?) mylar at the SEGS plants in Kramer Junction.Saw some 4.5 year old that looked to be in fine shape on the RR site.

I like the reflective cooking setups myself.

Thanks again for the links as always. :cowboy:

BooBoo