Chest freezer as water storage tank?
 

I'm wondering if anyone knows what the R-value is on a chest freezer, and if anyone's ever thought of using one as a hot water storage tank for a solar heating system?

It seems to me that those old gigantic freezers would serve a new purpose as a hot water storage tank for a solar water heating system. but would they be strong enough to retain that much liquid without reinforcement? Or what about half-burying it in the ground to add some strength/insulation? thoughts?

Interesting idea cdig. The first thing that would worry me is the plastic lining. Can it hold up to the water temperatures it would see? I think adding insulation would definitely be a good idea. Other than that, I don't see any problems, except possible leaks.

yeah, I'm thinking it would be a good idea to insulate the inside with a layer of foil-backed insulation and then put in a plastic liner.

I'd also want to test it outdoors. If it isn't structurally strong enough to hold the water (which really weights a lot)... well, you don't want that anywhere in the house. :)

yeah I'm thinking more and more of adding a solar shed on the side of my garage, it would house the water tank, provide storage for yard stuff, and also be a heated place to put a sandpoint pump for watering our horses.

I really do like the freezer. There is always someone selling those things or willing to give them away if you come and pull it out of their house. It could be a sizable cost savings in a solar hot water setup.

That is a great idea, I was looking into a hot tub, an old beat up one with a cover and everything for $50 on craigslist.

so I picked up my free non working chest freezer from craigslist sunday and hauled it home. Its 14 cf so I think thats about 100 gal. my friend has some left over epdm roofing material he is going to give me so im gonna fill it with water and see what happens.

Nice! Be sure to snap some pictures if you can for us. :)

So I filled it with water yesterday and let it sit, it actually held up very well, didn't even bulge. I want to add some bulkhead fittings to it so I can run the 1" pex for the exchanger coil and the 1/2" pex for the collector lines through the side but the only problem is that the wall is about 3" thick and I cant seem to find any cheap ones this long, any ideas? I dont have my camera at home yet but as soon as I get it I will take some pics.

that's awesome Joe! I'm glad someones trying my idea, I haven't had the time just yet...

For the bulkhead fittings, what about some plain old copper tubing? you could solder on fittings on the inside and outside.

not a bad idea but I kinda wanted something I could put silicone on and tighten down to seal it. I think I might go to home depot tomorrow and look around to see what I can rig up.

there are brass fittings with threads on both ends, used to attach bath tub spouts. They come in different lengths.

cool I will check those out, I am going to put the tank on hold right now, I just started working on the collector, I will resume this when I get it done.

I like your idea. Have you gotten it hot yet? Question number two, how big of a chest freezer are you using? I need 20 square feet or about 150 gal. I am wondering if yours is that large. I sure don't like the prices on solar thermal storage tanks.

Another question, How well does the PEX tubing work as a heat exchanger? Copper is probably better but pretty expensive. Anyhow I love your idea. Hope you don't mind if I steal it for my home.

PEX doesn't work all that great, so you need a long length of it. Gary on builditsolar.cm has some info on PEX and other cheaper plastic tubing as heat exchangers. Basically, you just need a lot and it takes up a lot of room. If you have the room, it'll work.

I picked up some in-floor heating tubing awhile back that I'm going to try on a project. Not the cheapest stuff out there either but it's better than copper and can take the heat. Good heat exchange properties too, since it's designed to do just that.

Is your in-floor heating tubing PEX? I'm pretty sure that PEX is the most used un-floor heating tubing,

-AC_Hacker

Years back in my early solar heating experiments I used an old chest freezer for my heated water storage. I put a water bed bag inside to hold the water. My water temp was an average of 160, the bag never leaked.

mike

No structural problems?

-AC_Hacker

I had no problem at all with the plastic liner in the freezer holding the weight of the water. Recently I was looking over some junk at a farm sale and opened a chest freezer that was setting outside under the eve of a garage. The freezer was completely full of water with no signs of structural failure. I had quite a few years back made up a freezer for ice cream by placing a five gallon bucket in a four cubic foot chest freezer surrounded by water and freon pipes plumbed to an outside heat exchanger. No compressor, just used the outside cold to freeze the water via convection. No problem with the frozen water either.

mike