SOLAR THERMAL SYSTEMS
Solar Thermal systems convert sunlight into heat for various forms of end-use; space heating, water
heating, industrial process steam, cooking, absorption cooling, crop drying, solar greenhouse, salt
production by brine evaporation, desalination, and electricity production.
These indirect applications of
solar energy are distinctly different from photovoltaics which produce electricity direct from sunlight
without the intermediate thermal conversion.
While the use of solar energy has been evolving over many years, concentrated research and
development were initiated in the early 1970's after the first oil shortage.
The realization that the world's
fuel supply is finite, and its cost is subject to large swings, motivated a vigorous worldwide response to
develop renewable energy (primarily solar) alternatives.
concentrating and converting sunlight for useful purposes has been examined.
Many were carried to test
The more promising components were retained and improved over successive generations of
Many fully functional prototypes were built and tested around the world.
growth in solar energy activities slowed down and somewhat reversed in the 1980's coincident with the
decline in world oil prices, and equally important, the projections for reduced future oil prices.
the volatility of the oil supply, and the growing energy needs keep the interest active in solar
In the 1990’s and 2000’s there have been many commercial deployments of concentrated
solar power (CSP) projects around the world. Examples can be found in the United States, Australia,
Japan, France, Germany, Spain, Italy, Canada, China, India and several countries in the Middle East.
Today domestic and institutional solar water heating is commercially feasible in many parts of the
Also, solar heating of residential buildings is rapidly approaching commercial status in the United
Both active and passive solar heating systems are being installed, and several manufacturers are
test marketing solar heating components and total systems.
The highly focused activities in this field during the last thirty years should not lead anyone to think
that the use of solar energy is a new concept.
Farmers in India are known to have dried their crops in the
sun for several thousand years.
Making salt from seawater using solar energy has also been practiced
for thousands of years.
Ancient Greeks and the early Indians of the American Southwest understood
passive solar concepts, and built their dwellings facing south to utilize wintertime solar energy.
Rome, noted for its legal codes, had the first solar rights law.
The first patent of a solar water heater