PROJECT 42

SUN HOSE WATER HEATER

This project is an experiment in solar water heating.

Most preppers, homesteaders, and anyone else interested in sustainability or living more ecologically minded are enthusiastic about solar energy. In my experience, solar is much more efficient and easier utilized when it is used for heat rather than electricity.

This is because of the efficiency losses when transferring one type of energy to another (as we discussed in project 34).

Absorbing the sun’s heat and using the heat directly is the easiest way to use solar power, and by using solar heat for water, we save energy (either electric or fossil fuels) by not having to run a water heater.

It is possible to construct a solar water heater that is plumbed directly into a home’s water system to either pre-heat the water going into the water heater, or to replace it.

This system is better used to wash dirty hands and feet before going back in the house, a dirty dog, or a pre-swim rinse than to use as an actual shower, but I have used this at the land to get a hot shower after a hard day of camping and building.

Material:

•   100–200 feet of garden hose (black is best)

•   Sheet of clear plastic or tempered glass (optional)

•   Sheet of black plastic (optional)

Procedure:

1.     Locate a spot in full sun that won’t be bothered; many people choose to put solar water heaters on their roofs, but for this project we will stick with ground level.

2.     For best results lay out a sheet of black plastic for the hose to sit on. This will help absorb the heat from the sun.

3.     Lay out the hose on the plastic (or straight on the ground). Depending on use, available light, and how quickly you need the water, some layouts work better than others. Experiment with a spiral coil and a back and forth zig-zag pattern. These are the most typical ways to lay out the hose.

4.     To weigh down the hose, as well as to help trap the heat, cover the hose with a piece of tempered glass or plastic if you have one available.

One hundred feet of black hose will heat up in about thirty minutes, and will give enough warm water to for a quick shower. Two hundred feet will allow for a more “normal” shower time.

Be careful though, in the full sun of a hot summer afternoon, the water may be too hot for a safe shower, but it would work very well to wash clothes. With a “Y” and a length of hose to a water spigot, you could mix the hot water with cold to get a cooler (but longer) shower.

Lessons Learned:

This is a good introduction to thermodynamics, even if you don’t mention the term. This project shows that heat can flow just like water. You can get the heat to rise. I like this project because it is pretty much foolproof, but free experimentation and a little knowledge allows it to be tweaked for better efficiencies. A young scientist or experimenter can keep records of daily temperatures, time in the sun, layouts of the hose, and starting and final water temperatures to really begin to learn about solar heating.