Residents of any sustainable community will heat their water through some renewable source of energy such as biomass or solar. Even wind can heat water if it is converted into electricity and fed to a heating element in the water. The advantage of using wind this way is that electrical regulation is unnecessary as long as you have water to heat.

It might be practical to design a hybrid system in which electrical power from wind is used for lighting, etc., and any excess I used to heat water.

I apologize that these water heating projects are also covered (in more detail in some cases) in the section on energy. My rational however is that they are quite relevant to this subject as well. I bring this up to spare you the time in case you have already read, or intend to read the section on energy.

I did an experiment for a couple of weeks, where I bathed with no more than two gallons of scalding water (diluted with cold water as required of course). The technique was to use warm suds in a pool about an inch deep in the bottom of the tub.

I was surprised that I was able to get a very thorough bath and rinse, and still have hot water left over. The real value of this experiment was that I demonstrated heating the water in a cardboard box!

The contraption was basically three layers of foil-lined cardboard, with a double layer of glass over it. Don’t underestimate the value of the foil. Although totally lacking in insulating value, shiny aluminum reflects infrared radiation. Considering that thermal radiation increases with the fourth power of the absolute temperature, this loss can be significant unless you enjoy cold baths – ugh!

The water was heated in a couple of black-painted gallon milk jugs. They were resting on a shallow sheet-metal pan also painted black. With this cheap simple arrangement, water would still be too hot to use directly for some time after sunset.

When I returned to a more "civilized" bathing pattern, I began using it as a solar cooker, and found nothing I couldn't "crock-pot" during the course of a day. These challenges included beans, and even baked potatoes. For proper cooking, the food needs to be in a dark container. The cheap black or dark blue enameled cookware common to supermarkets and developing nations is ideal.

In all fairness, I need to add that most of these experiments took place during the summer time, but the potential for year-round usage is obviously there.

Another important detail is that it must either be propped at an angle so the sun can shine directly into it on its path, or set up some kind of a reflector arrangement.

A simple water heater can be inserted into a flue system to scavenge energy that would otherwise escape.

A U-shaped piece of 1/2" copper pipe is suspended in at least a 2’ section of flue. Even though this pipe is exposed to orange-hot flue gasses, any solder joints will not melt, because the pipe will be filled with water.

I connected the ends to a five-gallon can suspended from the rafters in my shop, with 5/8" automotive heater hose. The connections to the can were made to pieces of 1/2" copper pipe – one soldered into the bottom, and the other soldered about half-way up the side.

I messed around with a version of this that was connected to more fire and a 55-gallon drum, but never got around to completing the project; I did get far enough however, to say with certainty that it can be done.

To really be practical of course, any such container would have to be insulated. Something I didn’t think of until I had how water was a little faucet in the bottom so that I could actually use the hot water. Obviously it would need to be refilled any time the water level fell below the upper tube, or the upper tube will produce only steam – yet another lesson learned the stupid way. If you aren’t making stupid mistakes, it’s only because you aren’t doing anything either stupid or smart.

I have had several people enthusiastically tell me that they were able to heat water simply by pumping it through a coil of black plastic pipe that was laying out in the sun.

Half-inch black plastic tubing is one of the cheapest forms of tubing you can buy. According to my calculations, 250 feet of this stuff would create a flat doughnut with a diameter of 5-1/2 feet and a hole of 18". This would have an area of 22 square feet. If every thing was done right, this could increase the temperature of five gallons of water by about eighty degrees in an hour's time. If there were no losses at all, you could heat 10 gallons.

The water can be moved through the tubing by convection, which is based upon the fact that hot fluid is lighter than cold fluid, and therefore tends to rise. A convection system of any kind has the storage above the heat. This explains why the hottest water will be taken from the upper edge of the collector and fed into the top of the storage, while the coolest water in the storage will settle to the bottom, where it is conducted to the center of the collector.

It is crucial that there is no air in the pipe, and that the water level in the bucket consistently remains above the entry of upper pipe. A single tube-diameter bubble however, can keep convection from happening.

If you want to actually use this hot water, you're going to need to put a "T" in the pipe leaving the bottom of the bucket. If you want more than one shower you may need a bigger bucket -- might I suggest a half of a 55 gallon drum that was not used for pesticides? Be careful here, a 55 gallon drum full of water will weight well over 400 lbs, and would be an annoying visitor to entertain in anybody's shower.

Having said all that personally, I have had poor results in my minimal experimenting with solar convection, but I have met people for whom it did work. I believe the trick is to have a good difference in the height between the collector and the storage, use large diameter pipe for an easy flow, and beware of bubbles.

I did heat a 14’ X 3-1/2’ diameter plastic pool by forcibly pumping water through coils of plastic on the roof. It was very pleasant to slip into 95 degree water and a silent world of about 3:00 am.

I found that a 6 - to - 9 foot diameter coil of plastic can be difficult to manage. I also had trouble with different flow rates with coils at different levels on the roof. Thirdly, it took a lot of pressure to drive a good flow of water through hundreds of feet of pipe. Another mistake that kind of surprised me was that the black nylon tie-wraps deteriorated in the sunlight and became brittle after one season

1. I will be breaking the system down to multiple units of 4’ diameter tubes and mounting them on 4’ X 4’ pieces of plywood. This will make them easier to manage or transport

2. The tubing will be attached by wire running through holes in the board, rather than bound by tie-wraps.

3. They will be manifolded together so the flow will be in parallel, rather than in series. This will reduce the back pressure on the pump.

4. They will all be mounted at the same level on the roof. If there are too many modules to make this practical, they will be mounted in serial pairs – one high, one low.

As prosperity progresses, a small well-designed village may provide a centralized hot water system for the entire village, eliminating the need for hot water systems at the household level. There would also be a system for the irrigation of the village food supply. This includes a certain amount of purification and recycling of available grey-water.

As much as possible, water should originate from local sources, and be a key factor in carrying capacity calculations.