Turn excess attic heat into hotwater

Step 8 The End

It won't supply all my hotwater, but it does contribute and there is nothing to maintain and not likely to cause a roof leak.

Comments

[dangerdoug]

I like Tdrago's idea with the truck rads!! Do you brainiacs think that lengths of PVC piping in an attic would perform as well? Maybe strapped to the underside of the roof joists for maximum heat. Maybe not here in Canada, but for the southern states, I think it would be a lot less building and weight in the attic.

[Senseless]

The pipes would get covered in condensation and drip into the attic but yes it would work during the day.  The idea with the sand was to both store heat for use at midnight and to avoid forming puddles in the attic.

Next I'm going to try using two or three 40 gallon well tanks buried in the sand. I'm not getting as much heat transfer as I'd like with 300 feet of pipe, the water passes through it too quickly.

I had originally planned on pipes like you mention inside say a ten inch pipe filled with sand but getting the sand in there would have been difficult.

Carrying 3 tons of sand up there in five gallon pails was work enough LOL.

[Nostraquedeo]

!!!!!!!!!!!!!       DON'T use vehicle radiators!!!!!!

They use LEAD solder to build them since there not for human consumption. Please be careful!!!!!

[musick7]

I agree with Nostraquedeo. If you plan to be incontact with the Same water that travels through the Car/Truck radiators, you shouldn't, No Scratch that, Don't use car/truck radiators.

However, TDRAGO, it's a great thought but the Lead used to solder those together or lead that maybe in the material itself just isn't worth the health risk…
Still a good thought.

[iwilltry]

For a given volume, few materials are better than water in terms of heat capacity. Water is also more easily moved (ie via a garden hose) and has better heat transfer to pipes running through it due to convective heat transfer. An alternative design would be to run your pipes through 4 or 5 plastic 50 gallon drums filled with water (and antifreeze). These can be picked up for about $15 each used.

[Senseless]

I could probably get away without antifreeze here in Florida even with consecutive freezing nights the mass never got below 55 degrees. I'm thinking of redoing it using a few 400 foot rolls of that polytubing people use for sprinkler systems because the water here is so low in Ph that it corrodes the copper big time. I think if I run 3 or 4 parallel tubes of one inch 400 feet long I think I'd get enough water flow to not effect the the flow of water to the tubs or showers, but would keep it within the heated area long enough to make up for the insulating value of the plastic tubing. It's not rated for hot water but it won't get much hotter than 100 degrees and seems to average around 90.

[gregr]

You might look at the tubing they use in radiant floor heat.

[jsilve1]

if some one wanted bigger they could put it in a commercial building

[tdrago]

** A MUCH easier way would be to just use 1 or more old truck radiators. The bigger the better.
These are meant to contain hot water and only release water when the temperature of the cap is exceeded.
They could even be directly attached to the undersurface of the roof or elevated near the roof for maximum heat transfer. You could feed one radiator into a second or more radiators thereby further heating the already heated water... Might get TOO hot!
You could even get fancy and add a thermostatically controlled fan. There is a commercial product along these lines. See: http://www.solarattic.com/pcs1.htm

[TheMadScientist]

you could have your water system hooked into your computer with a bypass... just attach it to "water blocks" and use some thermal compound, water blocks circulate water and move heat away from the cpu and other things, so it should carry the heat with it, giving you more hot water!

[TheMadScientist]

(you don't realize how hot those small chips get...)

[Senseless]

I've burnt my thumb on many processors...

Ever use a Peltier device?

http://www.ferrotec.com/products/thermal/modules/?_kk=peltier&_kt=21f0c9bc-1382-4cbb-ad01-5773c9e8e9a0&gclid=CMvTzfTUnJACFQUbgQodZl4Qqw

[TheMadScientist]

yeah, i've wanted to try to take one of those massive heatsinks and move the heat piping out on top of my computer to see if I could hook a skillet to them and make myself breakfast on top of my computer...

[richt]

I remember my shop class going to a seminar on solar heating. I saw a box they were running water through and it had a small fan on one end which blew out hot water. I built one myself over a weekend with my dad, it was great for heating water and the rest of the house. Afterwards, we noticed during the winter that it did not heat as well, especially on those cloud covered winter days. We used a wood stove for heating the house during the winter. We ran copper tubing down from the water tank and wrapped it around the stove. We had to modify it a couple of times as the water was too hot, but it worked great. No cold showers.

[Greenlock]

Very interesting if not practical here in NJ where I live. I was thinking of doing almost the opposite by running my well water going to the sprinklers through a copper tube frame work mounted in the plenum of my furnace and using the fan to cool the house since we do not have central air.