The sun gives out
3.7*10 ^20 MW of energy into space, out of which earth intercepts one 1.7*10^11
MW. Solar radiation is reduced in intensity in the atmosphere by clouds, dust,
haze, and fog. The energy emitted by the sun in three minutes is equivalent to the
world energy consumption during a year. Most of the energy we receive from the
sun comes in the form of light, a short wave radiation, not all of which is
visible to human eye. When this radiation strikes a solid or liquid, it is
absorbed and transformed into heat energy.
The heat energy is
collected in a fluid, generally water. This heat energy can be used in a solar
heater or drier or can be used to run an engine. Flat plate collector or
parabolic concentrated type collector is issued to collect and concentrate the
solar energy and increase the temperature of the working fluid.
• Solar engines for
water pumping.
• Solar water
heaters.
• Solar cookers
• Solar furnaces.
• Photo-voltaic
conversion (solar cells).
• Solar power
generation.
The Image above
shows a solar power plant with a low temperature solar engine using heated
water from flat plate solar collector and butane as the working fluid. This was
developed in France for lift irrigation.