Global Warming, the Greenhouse Effect and the Solar Greenhouse
See what our planet may look like in the next millennium by clicking the Earth.
Energy
from the sun heats the earth’s surface, makes clouds and creates
weather. Atmospheric greenhouse gases such as CO2 and clouds trap some of
the outgoing energy like a great blanket. The greenhouse effect moderates temperatures
and makes life possible on this small green planet. The threat of global warming
may someday become a serious problem if the current trend of fossil fuel
consumption continues.
In the last 300 years the concentrations of carbon dioxide alone has increased
by more than 30%.Without adequate emission control policies and alternative
energies to choose from this concentration will most likely double during this
century. If the greenhouse effect continues to escalate many scientists believe
we will reach a point of no return. High temperatures mean increased plant
growth, more rain, more vegetable growth, more decay and more carbon dioxide.
More carbon dioxide increases the greenhouse effect, the cycle continues and the planet "hot
balls" into an inferno like Venus.
How can people prevent global warming?
The answer to this question is simple. All we have to do is stop consuming vast
quantities of fossil fuels and start searching for renewable energy supplies. We
need to explore alternative energy options such as wind ,water and solar energy.
Of these options solar energy appears to have the greatest potential over the
largest area. To avoid excessive global warming we can use the same principle
that' s causing it. .That's right! The greenhouse effect is a fundamental method of
trapping heat from the sun. High frequency radiation such as ultraviolet and
visible light is allowed to pass through a glazing. Once the light is inside the
greenhouse and it strikes a non reflective surface the high frequency radiation
is transformed into a low frequency heat radiation that can not pass back out
through the glazing. Heat is trapped.
A commercial greenhouse nursery is a great way to get plants
off to an early start.
A solar greenhouse can also be used to start plants although it's primary
function is to heat a house.
SOLAR GREENHOUSE
A
solar greenhouse is specially designed for heat gain. The glazing is
perpendicular to the angle of a winter sun. The upside-down funnel shape of the
greenhouse concentrates hot air near the top flap. On a 20 F., windy,
January day in Plattsburgh NY I measured temperatures in excess of 160 degrees
F. at the solar greenhouse apex. Hot air is lighter than cold air so it naturally
rises and pushes the top flap open. The cold air return flap is pushed open in a
like manner. This allows cold air from the living space to be returned into the
solar greenhouse for heating.
At night the solar greenhouse cools down so that cold greenhouse air attempts to
enter the house through the bottom flaps. This reverse circulation is prevented
by the simple plastic one way flaps.
The solar greenhouse is a good example of a passive
application of the greenhouse effect.
Active solar energy systems also make use of the
greenhouse effect.
Another good application would be the flat plate collector.
Heat from the greenhouse effect is able to boil water inside a well constructed
solar collector. Solar heating systems are now competive with fossil fuel
heating systems. Explore the alternatives while there is still time.
