Must Get A Life!

Shop deals on ebay
armeg
TaoTech_ElectricianForum2
Advertise with us
Talk Electrician Forum

Help Support Talk Electrician Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
steptoe said:
:pmsl:

default_God%20no.gif


:Applaud

ive been thinking about this,

I think that simply painting the pipes black and having a reflector behind them would be even more efficient,

Im not seeing how the cans are actually benifitting that much to the system tbh,

they would need to be totally sealed around the pipe to have a trap of hot air for any big benefit to be gained from them,

is there something Im not thinking of?

even have the cans on the reverse of the pipes for a parabolica effect would be a lot better, you could even polish them :D
Click to expand...
Yep, all fair points. It was an experiment albeit with little undestanding of the subject! Seriously though I read that the evacuated tubes are more efficient in cloudy climes but the flat plate type better for really hot sunny places. But I didn't want to start making vacuum stuff. The reason for the cans went on the lines of; black all round, absorbs heat from the front and by virtue of the shiny ali backing sheet the bottom. Then the angled sides direct it inwards a bit more. NOT so sure however on the stacked cans as you say, does that "all round" heat get transferred to the copper pipe? But.........is that heat in the gap between can and pipe "held" there and just added to? They are pretty much sealed - at the joints by paint (and expansion?) then at the ends with mastic. Without the thermal syponing going the outlet was at 83degC - NO idea how that compares to a flat plate. So............the answer has to be to make a flat plate job and compare.............

I did consider "halving" the can lengthways and using as a parabola. I even toyed with the old "trough" antennae idea i.e. concentrating heat onto a pipe............still might look at that. I've made a couple of large trough antennaes for neighbours and both are receiving Freeview on them (one from ali plate and the other from mesh).

 
Last edited by a moderator:
I may not be correct, [ask the wife] , but Im really interested in this,

its really good, just wish I had , the time, the resources, the kit, and the ability to do stuff like this,

maybe if I ever get this shed sorted I may be up for some stuff like this,

Im just trying to throw a different train of thought on it TBH ,

if your anything like me, sometimes you can stagnate on what you think is right, then someone else will say something totally obvious to me and I wonder WTF didnt I think of that,

not saying what I suggest is in any way better than what you have, just might be something to think if you are going to keep experimenting.

one thing you can be sure of,

its working!  :D

its just a matter now of deciding on what system is the best.

 
Onoff said:
Had to bend a bit as the tank is a tad low but it proves a point. Gave the wife and daughter a laugh too who videoed me - bless em! Just got a peek at the footage and it's 'effin frightening - like a white whale with a skinhead, moobs and a cider gut (ladies PM me!).
Click to expand...
You tube link?

 
Congratulations on you first shower, sounds like a fitting end to a successful project.

Maybe try something more low-tech, I'm not sure you'll be getting sufficient rewards to warrant all the extra work you put in with the cans etc.

I made a very low tech heater for our swimming pool. The pool is around 8mx5mx1.8m and my aim was to extend our swimming season by a month either side so I was aiming for a 4-5degree temp rise in the spring and autumn months. Obviously my volumes were higher and my delta t lower but It certainly did the trick, I got approx the temp rise I was after. In mid summer I ran the heater for a week as a test and it raised the water temp from 26degrees to 34degrees which was way too warm.

The pipe was 200meters of 25mm HDPE class10 which is very cheap, I used 2 pieces of recycled shutterboard and heavy duty foiled them. I had an old 300watt pump kicking around which I repaired. Total cost circa ZAR700.00 (250QUID)

IMG_4014.jpg

IMG_4020.jpg

I might add a glass cover later this year to improve the efficiency for the less sunny months.

 
Last edited by a moderator:
Marvo I'm trying the convince a plumber friend of mine to make the same thing, he just wants to put more electric heaters on it! I've even sent him you tube links to home made ones. I might offer to build him one at a price. The ones I saw was hose pipe sprayed black on OSB. Cheap as chips! 

 
The cost of running electric heaters for a swimming pool must be astronomical. I had a home-made diesel heater on our pool originally and that wasalso hellish expensive to run. Fuel prices have quadrupled in the last 10 years plus the heat exchanger eventually disintegrated hence to move to the solar one.

Apologies for my currency conversion mistake above, ZAR700.00 is actually around 50UK pounds, not 250 that I stated.

 
Last edited by a moderator:
Excellent solution there Marvo. Interesting that the pipe is NOT under glass..............I guess wind chill is not a huge factor out there?

I saw a guy put a complete roll of this black pipe in a ground positioned, glass covered box about the same size as mine as a pre heat solution for his domestic hot water........think that was in Florida mind.

 
Last edited by a moderator:
I think our climate would be similar temperatures to the north of Florida, we do get considerable wind in summer but not so much in spring and autumn. I need to do some homework on glass covers, I'm not sure what type of glass nor how I'd go about installing it on such a large heater (3m x 2m) but I'll look into it nearer summer.

 
Marvo said:
I think our climate would be similar temperatures to the north of Florida, we do get considerable wind in summer but not so much in spring and autumn. I need to do some homework on glass covers, I'm not sure what type of glass nor how I'd go about installing it on such a large heater (3m x 2m) but I'll look into it nearer summer.
Click to expand...
Will try and scan my book and send to you. Has a fair bit in there ref glass and plastic alternatives etc. PM me your email. 

 
Marvo said:
That would be greatly appreciated. You can send it to my [email protected] address, thanks. ;)  
Click to expand...
Just waiting for the missus to ask "Why are you sending emails to...............!" 

Anyway, just scanned the solar book as a PDF. Came out about 28MB so will Dropbox to your highly dubious email addy!

I've also got one on how to build your own snowmobile, would you like that too?  ;)  

 
Last edited by a moderator:
Off down the scrap bin again............more of a wander round the garden/shed etc. So, onto the flat aluminium panel design for "comparison" purposes. Got a nice piece of ali sheet:



I need though to "depress" halfway into the sheet a 7.5mm nominal radius for the 15mm pipe to sit in. First attempt with a bit of ali strip, a bit of 5/8" stainless bar and a Unistrut off cut:



Sort of what I'm aiming at:



Thinking it needs to be less of a "V" and more snug fit to the copper pipe...............thinking to ROUTE a radiussed (is that a word?) depression in a piece of timber, lay the sheet over that and hammer the rod down into it............

 
Last edited by a moderator:
Thanks for the book, much appreciated. We don't even get frost in winter so I would have much use for snowmobile plans but thanks for the offer anyway.

I'd try to get as much close tight contact between the copper pipe and the aluminium as possible to aid heat conduction between the two. You have about 20% of the pipe circumference in contact, maybe try more for 30-40% if you can. It would be even better if you run some solder between the two but I don't think it's easy to solder aluminum to copper so maybe some heat paste. 

 

Latest posts

Top