Hot water: green or cheap?

Both! Here's the story:

As most of you know, I live off the grid. Way off.

Because we're on solar power, having a traditional electric water heater is out of the question. With butane at $3/gallon, that gets expensive too, especially when you're living entirely on donations. Thus, for the last 8 months, I've not had hot water at home. This means cold showers every day.

So I've been looking for a solution to this problem. Especially since occasionally during winter, it can get into the 50's at night (poor me, right?), and that's an awfully cold shower.

A friend of mine sent me the attached plans to a solar hot water heater that's being built quite a bit in Brazil. They're translated (not terribly well) from Portuguese. I was able to understand them well enough to give it a shot though. The same friends came down from the States to visit and we decided to build it while they were here.

To spare you from the pain of having to decipher that document: here's a quick summary. As with most solar water heaters, there are two parts - a storage tank and a heat collector. The design uses as many renewable materials as possible. The heat collector is built out of "trash" - Empty plastic bottles and cardboard milk cartons - and inexpensive PVC pipe and black paint. For the tank I just used two different sized trash cans and filled the void between them with Styrofoam and that "Great stuff" spray-foam-in-a-can. It does not require any circulating pump as it relies on a thermosiphon effect to circulate the water.

My first effort at building it is admittedly a bit clumsy compared to the finely tuned ones that they build in the plans I've attached, but I think that I can fine-tune the design to make it cheaper, easier and more efficient using the materials I can gather here.

Bottom line: For about $100 USD and some time walking the beach collecting plastic bottles, I now have toasty hot showers at night. The best part: ongoing cost is $0.

If anyone is interested, I'll post some pictures of my build when I get a chance. I'm currently in the city for about 4 weeks.

Yeah lets see some pics !

What do you get for water temperature ?

Haven't measured the temperature yet. Sometimes I have to mix in cold water because it is too hot to shower just straight. I'm pretty sure I can increase the efficiency considerably though.

I'll get some pics when I go back next, but it might be a couple weeks. I have to be here in the city for a while.

That is pretty amazing you are getting it that hot.

I did like this line at the end of the document:

"Make your party, think about the collective and that God will help us to be rational"

Very interesting, will take a proper look later.

That is totally awesome, that you can get toasty hot showers with a scrapbuilt solar system. Impressive.

That is really cool. I love that kind of stuff:

One question, though (well, with two parts): I understand the plastic bottles, but what do you use the cardboard cartons for? And also, I really have no idea, but wouldn't those not weather as well as the plastic containers?

The cardboard cartons go inside the plastic bottles. They get painted flat black so that they can act as heat absorbers behind the pipes. I assume they use the milk cartons because they're made up to be in direct contact with liquids and survive nicely. That said, they don't get very wet since they're inside the bottles. They're also used per the instructions because they won't bend and deform at high temperatures as the air inside the bottles heats up. Here's some pictures from the instructions that show how the cartons are used:



I didn't use the carton material, because I couldn't collect it on the beach and we don't use enough product in that packaging to make it worth waiting until I collect some. We had some rolled subflooring material that was flat back and made of some kind of foam so I used it instead. Seems to be working ok so far. I'd imagine that roofing felt would also work, but each item you use that you have to purchase steals from your bottom line and makes it less green .

I would say if you need to blend with cold whatever you did you did it right

So would copper pipe in the collector work better than PVC ? I would think PVC would insulate the heat from the water inside the pipes ?

Copper would absolutely work better! But it's way out of my budget. Have you seen the price of copper lately?

Yeah i'm not suggesting you need copper just theorizing. The spirit of the how to sounds like they want you to use whatever you can find laying around and save from the dump.

Sure. And after taking several months of cold showers, my threshold of declaring success is fairly low. "Not cold" does it for me.

In the bigger picture, I'm training guys from the local village to make them. Hopefully, this can turn into jobs and income for some families in our village.

Okay, the water heater is neat, but that is totally awesome.