The Basics of Solar Steam Power

Most people know that solar power can be used to generate heat or electricity. However, when combined with steam-engine technology, solar steam power from the sun can be used to create clean mechanical energy as well.

Old-world steam engines used coal and wood as a fuel source but produced lots of soot, smoke and carbon dioxide. The fuel would boil water to create high-pressure steam which would then be used by a steam engine to rotate a piston.

The piston would be connected to a shaft that would turn mechanical arms or operate pumps in a factory or mine. Updating this design to use solar energy may be a little less efficient, but it is also much more environmentally-friendly.

Since the sun's energy is abundant, free and non-polluting, it makes sense to use solar energy to drive our machines. However, since sunlight is spread out over a large surface area, it has to be first concentrated to produce enough heat to change water into steam.

Solar steam power consists of the following components:

• Solar Collector - A collector such as a lens or a mirror concentrates sunlight to a central point to create a 'hot-spot'.

• Heat Transfer Point - The concentrated sunlight is focused on a metal transfer case where water is heated into steam. This equipment, and all connecting tubes, must be able to withstand high temperature and high-pressure.

• Steam Engine - This pressure-sensitive chamber uses high-pressure steam and normal atmospheric pressure to move a piston. The piston is connected to a shaft which can be used to turn mechanical equipment.

Even though the combined technology looks promising, it does have its drawbacks. For instance:

• Steam engines are not as efficient internal combustion engines. It takes larger steam engines (or a higher number of them) to do the same amount of work as an internal combustion engine.

• Steam engines require more maintenance than other types of engines.

• Using the sun as the power source means that steam power will only be available during daylight hours when the sun is shining. A simple interruption, such as a cloud going overhead, will stop the engine.

• To provide enough heat to create steam, sunlight needs to be concentrated by a lens or reflected by mirrors to a central location. Large lenses or parabolic mirrors are expensive. They also have to be constantly realigned to follow the sun.

Solar steam power is a combination of old-world technology with new world's need to use a non-polluting energy source. Even though it is not as efficient or convenient as modern engines, it may find some practical use in non-critical applications.