Source for reflective Mylar?

[myxpykalix]

I'm working on ideas for a solar water heater for my hot tub and i'm getting a old water heater to strip and use the tank for storage within a box that will have a mylar backing to reflect the sunlight onto the tank within a box i'm designing on the bot.

Has anyone ever designed anything like this?, advice would be appreciated. I'm learning from youtube videos. If you have suggestions for mylar suppliers or other parts would be great.

[geneb]

Jack, I buy Mylar from http://www.mirrorsheeting.com - they have a nice selection and the material is good quality - I'm using it for a spherical section mirror.

g.

[Brady Watson]

Ya gotta watch the heat with the mylar. It can get mighty hot in there & melt the mylar film.

Studies have shown that white is nearly as effective as mylar for solar reflectivity. Just something to consider.

-B

[michael_schwartz]

The version I have seen is just a plywood box, with a Plexiglas top. The hot water heater was painted black, and placed inside. It gets used for an out door shower, and the water temp gets up to about 120 degrees in the summer.

[myxpykalix]

Brady,
I'll keep that in mind. I'm going to be experimenting with different avenues on this.

One is where i just heat up a big tub of water in the tank and the other is where water runs thru a series of tubes and with "parabolic reflection" (?) the water is heated up and circulated.

I hope to be able to hook the system up so that it circulates into and out of the hot tub.

If that doesn't work i'll just set a big pot on a wood fire, throw some carrots in and like Elmer Fudd, hope Bugs Bunny jumps in...
"eh...whatcha cookin, Doc...? Rabbit stew...:D
(come on, i know you old guys are laughing right now...:))

[Brady Watson]

Jack,
Saving $$$ on heat isn't funny at all. It is the bane of all construction related craftsmen...

I take it you've been here & sniffed around: http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

-B

[myxpykalix]

Come on Brady, you didn't think i was serious about the pot of water under the fire? lol I should have used this icon afterwards:rolleyes:

I had not seen that link you supplied so i'll check that out, thanks for that one.
I have looked at several different methods for heating, things from "evacuated tubes" to things as simple as a rolled up coil of copper tubing.

I have some extra pumps from jacuzzi tubs and other things and guess the best way to try to make this work is with a semi "closed loop" system where the water goes in to the heating element gets heated up, drains to the hot tub then water is sucked out reheated, recirculated.

I have to figure out a way to cycle the water thru the system.

[gene]

Does that mean there aint gonna be no rabbit stew?

[Brady Watson]

I knew you were kiddin about that part ;)

I'm sure everyone would agree - paying for heat in the dead of Winter just plain sucks...I estimate I saved about $3500 last year with the wood stove. I burned thru about 4 cords and only used about 20 gal of oil. A few days of cutting standing dead and splitting is money in the bank.

I looked into many of these solar projects during the Winter. I don't have time to fab anything yet, but will be doing a BIG trombe wall for the barn & some kind of solar water heater for the basement heat. We don't really go thru that much hot water, so all efforts would be for space heating.

-B

[myxpykalix]

"but will be doing a BIG trombe wall" What is that?

I IDEALLY would like to make a system that was big enough to heat my basement like you also. That is where the "Mancave" is so the big screen and lazyboy and my popcorn maker, ect but in the winter time the floor is so cold i'd love to retrofit some kind of radiant heat also.

[Brady Watson]

Trombe wall: http://en.wikipedia.org/wiki/Trombe_wall

and: http://www.builditsolar.com/Projects/SpaceHeating/solar_barn_project.htm

A similar idea is the soda can heater: http://blog.hemmings.com/index.php/2007/04/26/almost-free-garage-heat-just-drink-a-lot-of-soda/

I bought these plans a while ago. They seem pretty good & Über easy to build - especially if you own a Bot: http://www.ffwdm.com/solar/order-page.htm

-B

[alister]

I bought some plans for this pool heater ...seems bot friendly.

http://georgesworkshop.blogspot.com/2005/08/parabolic-reflectors.html

[Gary Campbell]

Jack...
Paint the tank black. Line the inside with foil foam. Use Safety glass on the lid. Plexi deteriorates and may block the IR.

[bleeth]

Forget a big tank. Standard solar pool heaters are recirculating coils in a "hot box" with glass top exposed to the sun. A 6 x 6 one kept a full size pool we had warm all year but this is Florida. This is another one that isn't really rocket science at this point since they have been around for decades. If I didn't monitor it carefully the whole pool would get as hot as a hot tub! As I recall the glass was black and tempered and the pipes were copper.

[toddmaci]

Trombe wall: http://en.wikipedia.org/wiki/Trombe_wall

and: http://www.builditsolar.com/Projects/SpaceHeating/solar_barn_project.htm

A similar idea is the soda can heater: http://blog.hemmings.com/index.php/2007/04/26/almost-free-garage-heat-just-drink-a-lot-of-soda/

I bought these plans a while ago. They seem pretty good & Über easy to build - especially if you own a Bot: http://www.ffwdm.com/solar/order-page.htm

-B

Brady,
Here is one similar to the pop can heater.

http://www.youtube.com/watch?v=bRZvAAqzXIw

I used the bot to cut all the ridgid insulation.

Best,

Todd

[myxpykalix]

Tod,
What system did you make? I liked the video you posted and it looks like a neat unit but i couldn't pay $2800.00. Got any pictures of the system you made? How does it work for you?

[Brady Watson]

Todd,
That was the one I was thinking of...but couldn't find the link. Thanks.

Jack,
There isn't much more to it than what you see...There are several examples of these on the net. Check out the BuildItSolar page. I think there is a link that shows you a similar one apart.

I say good for this guy to make $2800 on a unit. I love those big profit margin products. It's a good time to be thankful we have CNC machines that can make all kinds of stuff that would be difficult with caveman/knuckle-dragger hand tools.

-B

[bleeth]

Jack:
Although the link below leads to a system obviously developed using extremely high end materials and heavily researched data I believe you should be able to adapt it to your needs relatively easily:

http://www.youtube.com/watch?v=Wc5mn2hXYds&feature=related


:D :D :D :D


"Kids say the darnedest things."

[Gary Campbell]

Dave...
I think you have a winner. Now, if Jack can just find some free aluminum foil, the project meets his usual budget requirements. That is, if the kids will work for free! :D:D

[Brady Watson]

If for nothing else, you'd at least be able to make a foil hat... :D

-B

[myxpykalix]

Dave,
I had saw that video you linked...that was my inspiration!

Gary,
I can get the kids to work for free...as long as I pull out my belt:D
(more like wallet, actually)

Brady,
I already have my tinfoil hat made. I wear it under my shopbot hat because as you must know the government is monitoring our thoughts already and the only way i can keep them from learning my thoughts is to interupt the flow from my brain to the tiny transmitter they implanted in my tooth.:eek::rolleyes:

And don't even get me started talking about my alien abduction:eek: