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
- 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.