Solar Power & Energy

Solar water heating works simply by allowing the sun to warm up your water naturally. Now that sounds simple and it actually is, but there are many different ways to create homemade solar water heating systems yourself, and you can buy commercial solar hot water systems too.

The simplest way to get hot water from the sun is to put it in a glass jar and sit that jar in the sun. Have you ever heard of “sun tea”? Sun tea is a popular way to make iced tea in the hot desert areas of the United States. Instead of boiling water on a stove, you put water in a glass tea jar. Then add your tea bags and sit the jar in the sun for a short while. Depending on what time of year it is, you’ll find the tea in that jar is hot enough to scald you in less than 30 minutes.

And that’s the crux of solar hot water heating too. You can sit a jar of plain water in the sun and have it heated up naturally too. This is exactly how solar showers work too. Instead of using a glass jar however, a solar shower usually uses a clear flexible plastic bag. You simply hang that bag in sunlight and it heats up naturally. Solar water heaters work in similar ways, but these systems usually involve moving the water across a hot surface.

You can use a simple piece of corrugated metal for another easy solar water heating experiment. Lay the piece of metal in the sun and cover it with a piece of glass. Then trickle water slowly down the corrugated valleys - under the glass - and it will come out warmer on the other end.

What happens here is that the sun is heating up the metal. The glass on top is helping to focus the solar energy of the sun so the metal heats up more efficiently. Then as the water travels down the troughs of the metal, it picks up the heat from it along the way.

Neither of the above examples are overly efficient for long term solar hot water production though, and that’s where the various systems come into play.

In most cases, a simple do it yourself solar hot water system will be self contained. In other words you won’t have to pour the water in one end and collect it on the other. Instead the water flows through small pipes, which it enters and exits automatically.

The solar water heating tubes are often small copper pipes, but there are some great ways to use old refrigerator coolent grills for this too. The concept is the same as the corrugated metal example above was: Heat the metal pipes with the sun’s energy, and run water through those pipes so it can collect the heat as it travels. This type of solar water heater system is known as a flat plate collector.

A similar system to this is the evacuated tube solar collectors. Instead of using metal tubes with glass over top, the tubes in this system are transparent glass themselves.

Larger versions of these types of solar water systems involve using holding tanks instead of small tubes. A system like this would have 2-3 small tanks - such as barrels or old water heater tanks - painted black and held in a closed container which has glass on the surface. The tanks are usually connected together by tubes so the water can move through the system as it heats up.

In this type of system, cold water will generally come into the first tank either via passive means or through a pump system. The sun heats up that black tank quite well, so the water starts warming up inside too. After heating up to a certain point it usually travels through another tube to the next black tank, to be heated further. This continues with additional tanks until the hot water exits out of the heating system at the tap in the house.

As you can see from just this brief report, solar water heating systems don’t have to be complicated or expensive. In fact, another super simple way you can create one yourself is by using a regular old water hose.

Black water hoses work best for this approach, but any will do. Lay your water hose out in a sunny spot of the yard and run water through it. Let the hose fill then turn the water off. Leave it sit in the sun for awhile then come back and turn the water on again. You’ll notice the first bit of water that comes out of the hose will be hot.

Now, you can maximize the water heating inside the hose by using glass soda bottles. Carefully cut the bottoms off of several glass soda bottles, then run your water hose through each one. Lay it back out in the yard with the bottles and all, and you’ll notice the water heats up even better the next time you try it. If you simply leave the water running through the hose slowly, you’ll continuously get hot water from it naturally.

This type of homemade solar water heater won’t take care of all your needs of course, it’s just a simple way to get started and see for yourself how well solar power can heat up your water for you. If you want to take full advantage of natural solar hot water, you’ll want to create or buy a solar water kit or system.