Thursday, January 8, 2009

Ammo Can Heat Sink

I have decided to use 30 MM ammo cans filled with water for a heat sink wall in the sunroom. The cans measure 18 1/2" long by 9 1/2" deep by 14 1/2" tall and hold about 10.5 gallons of water apiece. They are stacked 3 high against the rear wall. During the day they sit in the sun absorbing heat. In the evenings they radiate that energy back into the room keeping the plants warm and saving on heating costs.

The ammo cans are painted black and the metal conducts heat through to the water much more efficiently than plastic walled drums. The cans filled with water are heavy but easily moved. A steel drum would have been adequate but difficult to shift with the seasons and would sit awkwardly against the wall. The square shape of the ammo can is optimal for lining the walls. Minimal space with maximum heat gain.

I tested this last winter and it works. I will get some pictures up as soon as I can.

Pick up your own surplus ammo box and cut your heating costs.

10 comments:

Anonymous said...

Have you thought about some of those black plastic trash cans. I'm sure you could pick some up for maybe $5 a piece or so. They'd hold more water and I'm sure are cheaper then ammo cans which have much better uses.

BigBear said...

I don't like the size of the trashcans they are cheap though. The metal sides of the ammo boxes transfer heat much much better than plastic.

Hoozyrdady said...

Are you concerned with rust? If you add chemicals to the water, how will you dispose of it?

HermitJim said...

Sounds like a great idea to me. Let me know how it turns out...

Have a good one.

Stephanie in AR said...

Could you still use the tops for placing planting flats on? The warmth underneath would be good for seed starting & good seedling growth. Seems it would use what could be wasted space & the flat could be insulators- which would be bad if it kept heat out.

BigBear said...

not to worried about rust I dumped one of the cans out this fall and it was clear water...some floaties but no rust. That may change but we will see.

Mayberry said...

Great idea Big Bear. Metal boxes will take a very long time to rust out when filled with fresh water. Metal needs oxygen to rust, and a full can of water displaces most of the air. The most likely place for those cans to rust are on the outside bottoms, due to condensation being trapped against the metal there, and being exposed to air. Set them on a couple hard plastic strips or something that will allow air circulation under them, and even that won't be a problem. Don't use wood, as it will trap moisture against the bottom of the cans and cause rust.

Billybob Cornfed said...

Cool idea on the ammo cans - gonna pick some up!

Is that little orange car a Ford Feista or Festiva? I had on = awesome ride! Picked up a heavy duty truck Dodge 1ton 1982 - longbed - get it in the morning. Original owner - gotta get tires but all good! Now when ya gonna sell me a small piece next to yours so we can build a defensive perimeter?
Jeff

BigBear said...

1978 Ford Fiesta. They switched over to the Festiva a few years later. Great car I can fix anything on it tuff little thing. And gets huge better gas mileage than the truck.

Billybob Cornfed said...

just tough to haul hay in - that is what the long bed is for - ranch truck!