by
Paul
BenhaimFour-fifths of the sun's energy falls on the sea, driving the
water cycle. Ocean evaporation causes rain to fall on the land,
creating the global hydropower resource. The remaining fifth,
which falls on land, is still about 2000 times greater than the total
world energy demand. This can be captured using a variety of
solar technologies.
There are three different ways we can capture the sun's energy:
Passive
Solar
Space heating by conscious design of buildings. Using buildings to
collect the sun's warmth was a technique the early Greek and
Roman builders developed into a serious form of solar
architecture, as did the builders of the Pueblo villages in the
American south-west and the Inca builders in Machu Picchu.
Forms of solar architecture were also developed by Muslim
architects, who used the minarets of mosques as solar chimneys.
Solar
Thermal
Using solar energy to heat water. A solar water heater is, at its
most simple, water pipes painted black to improve heat
absorption. The small diameter of the pipes ensures that a large
surface area of water is exposed to the sun. The pipes are placed
in a small 'greenhouse' to insulate them. Originally developed in
response to a steep rise in oil prices in the 1970s, solar water
heating got off to a very rocky start. The wild claims and poor
engineering of many 'cowboy' manufacturers and installers
undermined the credibility of the industry on both sides of the
Atlantic.