Turn Excess Attic Heat Into Hotwater
Intro: Turn Excess Attic Heat Into Hotwater
I was wondering if I could heat the water in my swimming pool using the heat in the house's attic and I started messing about with a large <s>heatsink</s> thermal battery. The water for my hotwater heater has to pass through it and picks up free calories which saves on the power bill quite a bit of the year. Even on winter days it adds some heat to the water and every calorie free is one I am not paying for...
http://senseless.livejournal.com/152881.html
http://senseless.livejournal.com/152881.html
STEP 1: Make a Big Box.
I was worried about condensation on the pipes and also concerned about freezing even though I live in Florida so I decided to try a large box of sand. I used about two cubic yards and mixed it with two sacks of mortor mix to prevent it from turning into a giant hourglass. In the event the house is knocked down in a hurricane, it will just crumble and that will be one less thing I have to clean up.
STEP 2: Stick in Some Pipe
I tried CPVC first because it was easy.
STEP 3: CPVC Has a Surprisingly High R-Value
I began to experiment and after modifying a large tank I began to circulate hot water to try and warm the box of sand. After burning everything I could find, I began to realize that for the water to run in hot and back out hot and the sand to remain cool I was not transferring any heat.
STEP 4: Boyle's Law
I forgot to keep an eye on it and add water. When the water got low enough for it to start circulating steam instead of liquid, the pressure spiked and it made a very loud noise.
The sand was still cool...
The sand was still cool...
STEP 5: Never Fear!
Just make it bigger.
I added 150 feet of 3/4 copper tubing primered and painted to protect agaisnt corosion.
This doubled the original size of the experiment but it began transferring heat.
I added 150 feet of 3/4 copper tubing primered and painted to protect agaisnt corosion.
This doubled the original size of the experiment but it began transferring heat.
STEP 6: Let It Warm Up
There is enough mass so that the tempurature will only swing up or down a few degrees a day, so in the summer it averages about 90 to 100 degrees. In spring ,fall and most of the winter it is still above the tempurature of the well water, so it is stil benificial.
STEP 7: Go Around It in the Cold
I can open an irrigation valve and bypass the water around the box if it ever gets colder than the well water here. I'll use a sensor in the box to open the valve, otherwise it is shut by default.
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.
73 Comments
Timmy P 15 years ago
thisonebiglife 12 years ago
Timmy Dont 12 years ago
beernut 13 years ago
dangerdoug 14 years ago
Senseless 14 years ago
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 14 years ago
They use LEAD solder to build them since there not for human consumption. Please be careful!!!!!
musick7 13 years ago
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.
EmmettO 14 years ago
doon01 14 years ago
k_man93 14 years ago
Senseless 14 years ago
Regular trusses would not support this weight and it would fall though the attic floor...
The house isn't built like most stick houses, I went out of my weigh (no pun intended) to make it take a very high windload and can sleep right through a tropical storm without a creak.
It's like a bunch of shipping containers tied together to form the rooms on the main floor.
I forget the load a standard truss can support but it is well below the mass I have sitting up there.
Overall I used 7 bunks of plywood, bundles, and about 50 cases of liquid nails, then covered that with sheet rock so it appears like a normal wall inside and a side effect is that inside the house is extremely quiet even though I live 500 feet from an evacuation route, US 331.
You can hear the traffic in my vids done outside but not the ones done inside.
For a stick framed house it is very very stout.
iwilltry 16 years ago
Senseless 16 years ago
gregr 14 years ago
jsilve1 14 years ago
tdrago 14 years ago
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
philip80 15 years ago
mulder 15 years ago
Rainh2o 15 years ago