Thermal Solar Energy Systems can be classified in two
main categories
- The Solar Heating Systems for Residential Use
- The Utility Scale Systems, usually Focusing Solar
Heat
Solar Hot Water Systems at Home
First lets discuss the solar hot water installations for
domestic use. Those installations can provide us with hot water, heating and
through solar cooling as air conditioning. We can even drive a sterling engine
on the heat the sun provides like that.
High Efficiency Breaks even within a few Years
These system are very efficient and can reduce your energy bill by 50 - 80%. For
your pocketbook this means that it takes about 3 - 5 years before the 3000 -
8000 dollar investment plus interest has paid for itself with
reduced energy bills. After that that you
are only profiting.
Save 50% on your Utility Bill
Isn't that a great idea, a reduction in the order of 50% on your utility
bill. and no worries about increasing energy prices.
Technical Workings of Solar Heating Systems
A solar hot water collector unit is made up of a series of thick panels
containing water tubes. And a black absorber plate that does exactly what the
name suggests absorbing solar heat. This heats up the water in the tubes that
can be actively pumped around. Or case of a passive system using the principle
of rising hot water to keep the water flow going.
It is possible to drive a stirring engine this way, but for home use that
still not very economical. Solar Cooling has more advantages, and is also a very
efficient process. Active solar cooling is using the same principle of
traditional cooling applied differently. The cooling through evaporation cost
heat. so does the expansion of a gas costs heat while compressing produces heat.
Active solar cooling works in between these mechanics. For a detailed
description we like to point you to our in depth discussion of active solar
cooling.
Utility Scale Systems CSP Systems
The second application of thermal solar energy is done on a utility scale. These
systems focus the suns rays into a focal point that gets very hot. Concentrating
Solar Power or the short industry term CSP systems apply this idea in various
ways. The end result is that we can produce sufficient amounts of overheated
steam to drive turbines and generate electricity.
Trough Systems
Most utility scale systems are so-called "through" systems. These systems use
long parabolic shaped mirrors to concentrate solar heat. Usually the liquids
used are oily substances a heat exchanger transfers the heat to the water in the
turbine system.
Dish Systems
A dish system has mirrors mounted on large parabolic dish and so concentrates
the suns heat one one focal point. The result is that very high temperatures can
be reached. A tracking mechanism keeps the system orientated towards the sun.
These systems are perfect for use in combination with stirling engines.
(http://www.stirlingenergy.com)
The Tower of Power
The last system is a CSP Power Tower. This application of CSP found practical
use in the South Western Part of the US. Imagine a tower surrounded by mirrors
that all focus their light on one point at the top of the tower. A tracking
device is used to keep the mirrors focusing on the top of the tower. The heat
generated in more than sufficient to produce the steam needed for the turbines.
Cost and Economical Considerations
The cost of electricity from these CSP systems is about 12 cents per Kwh, about
double the cost of coal fired plants. Because of the increasing knowledge and
advancements in technique a price of 5 cents is predicted by 2012. And when
looking through the lens of exploding energy prices this looks like a very
promising investment.
The future
Thermal Solar Energy has a great future. Both at home as on a utility scale.
