Our electricity has become so expensive. This year the cost went up 17 percent. We heat with electric, so the bill is really high. I've toyed around with the idea of building a solar water heater for some time, and have finally gotten started. The idea is simple. Heat the water outside, first, before it comes into the house. The basic supplies needed are a water tank, painted flat black, and an insulated box situated where it will get plenty of sun. As the water is pumped out of the well it will first cycle through the solar tank, where it will have a chance to get warmed up, and then continue on to the electric water heater, which will not have to work nearly as hard, if at all, to bring the water to a nice temperature for a shower. On a hot day, hot water should be free, right?
To get started I placed an ad on Freecycle asking for a discarded water heater. I got a nice response from a plumber in the nearby town of Blacksburg who told me he would have three to choose from available that weekend. I went and picked one up on Monday morning. Stripping it was more work than I thought it would be. The metal casement came off easy enough, but the insulation seemed to be some type of adhesive foam. Once it was stripped, I began working on the outside with a wire wheel attachment on the power drill. I discovered that the heater had two small leaks, probably the reason the original owner wanted to replace it. There was significant rust damage aroud the leak areas, but nothing my sanding discs couldn't remove. To fix the holes, I purchased a package of JB's WaterWeld. The package claims you can even patch holes underwater with this stuff and that it's safe for potable water. I haven't patched the holes yet, but I have cleaned them down to bare metal. One good thing I noticed is that while the outside of the tank was rusty, the inside looks great. It seems that the manufacturers do a good job of rust prevention on the inside of the tanks, but not so much on the outside.
Once I finish cleaning and sanding the tank, the next step is a nice coat of Rustoleum High tempurature flat black paint.
More to come on this project soon...
4 comments:
I have thought about this before too. Why did you strip the insulation off the tank if you are going to put it in a insulated box? I understand taking it off the tank to allow the suns heat to easily pass. My idea was too try to keep the water thin and the surface area large so as to gather more heat and quickly transfer it. Also the box you put the tank in should be painted white on the inside (even better get ahold of some old mirror glass cheap or free).
Another idea of mine was to bring the cold well water inside the house to act as a heat collector. It would be a dual benefit of cooling the house and taking some of the workload off the water heater. The mechanics of this seem a little intimidating if not ridiculous, though.
Hot water is nice and it sure is missed when the electricity goes out but what good is it if its stuck outside with out water pressure?
Answer: Place a holding tank at a higher elevation the your homes plumbing by constucting a rig or just using your landscape if it permits. You will always have a limited supply of gravity fed water when the power is out.
Let us know how it works and how much you save!
The tank needs to be stripped because otherwise the insulation on the tank would keep the water cool. Just like a thermos keeps water cool on a hot day. I want the tank to absorb as much heat as possible. Mirror lining is a good idea and I do have one that I may use. But I think Lowes has some foam board insualation that has what looks like a tin foil coating on it and I think that will work pretty well for lining the inside of the box.
The cold water will still go from the well to the house first because we need both cold and hot water, but I'm just going to put in a tee connector after the filter and pressure tank that will run through the solar heater and then run what comes out of the heater as the supply line to the hot water heater.
A flatter tank might work better, but would take up a lot more space to get the same gallons and would also lose heat faster at night so I'm not sure if it would be a net gain or a loss. There is probably some way to determine optimal tank size and shape but even if I could do that, I probably couldn't find a tank to match those dimensions. I know on a hot day the water that comes out of the garden hose is scalding, probably hotter than the 120 degrees that the water heater produces.
Sounds like a fun project. I guess with a trailer you do not have an attic? I would think that would probably be an ideal place to put it if you did have. I can remember working up in the attic on Dove Hill at times with Pop. I think you would lose a couple of pounds of sweat in a matter of minutes. As with anything else, there is a cost/benefit/practicality decision to make. The best of either of the three can often be the worst for at least one of the other two, so you need to find a good balance. What Jacob said about spreading the water out thinner makes sense, but how thin is thin enough? You could run all your water through radiators (similar to an autobile) in your attic, but that would be expensive to implement, especially since these would have to be of some material that does not rust and I suppose antifreeze in your drinking water is out of the question. Running great lengths of copper tubing across the underside of your roof (if you have an attic) would work superbly, but copper is extremely expensive now. What you've got going there should probably do just fine and it sounds like it won't have cost you much so you will be able to realize the savings even sooner. Hey, even if you see no savings, it was fun to work on, right?
There is no attic, but there is some space up there. I haven't decided exactly where to place the heater yet. We have a lot of tree shade, and that's great for summer cooling, but bad for solar. All the experts say to place the solar collector facing true south and tilting the collector (or in this case the glass lid) at approximately the same angle as your latitude for greatest absorption of solar rays. I had thought of building a closet sized tower on the back deck and mounting the heater just above the roof line. That way, at least the house wouldn't be shading the heater at any part of the day. But that seems like a lot of extra trouble, and the thing might work fine just sitting on the deck as is. Also don't want it to be too far from the electric water heater because there would be too much chance for heat loss as the water traveled through the pipes.
Check this out: Here's a link to the mother earth news article on solar water heaters that got me started:
http://www.motherearthnews.com/Do-It-Yourself/1984-01-01/Build-an-Integral-Passive-Solar-Water-Heater.aspx
And here is a great youtube video (look for part 2 on this as well) that shows a heater exactly like the one I want to build.
http://www.youtube.com/watch?v=C2Xe_glVoqc
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