|
Solar Energy
Solar energy is
energy derived from the
heat and
light from
the
Sun.
Basically Sun powers the
universe. In other words, most renewable energy forms (Wind, Biomass,
hydrothermal, geothermal etc) are derived from the Sun. This section
considers only discussion on solar energy coming directly from the Sun.
Solar energy is used to generate
energy for heating (as in hot water, home heating and cooking), natural
lighting (or “Daylighting”), mechanical power for domestic/industrial
engines and electricity supply for home and commercial uses.
Solar energy
is a renewable resource. A renewable resource is a resource that is able
to be replaced or replenished, either by the earth's natural processes or
by human action. Solar energy is available at varying proportions almost
everywhere on earth. It cannot be depleted unlike the
fossil fuel based energy
resources.
Solar energy is
a “clean” energy resource. It does not involve the emission of Green House
Gases (GHGs) that are believed to be responsible for the worsening global
warming of our planet, Earth. It provides a suitable energy alternative to
the traditional fossil fuel energy sources that are currently widely in
use.
Solar energy application can
be “passive” or “active”. Passive systems make use of direct light from
Sun to provide energy, without recourse to any mechanical or electrical
medium. Active systems, on the other hand, involve conversion and/or
storage
to
mechanical or electrical media that receive light from Sun and
transform the light to energy for final use.
Passive
Systems include Passive
Solar Heating (PSH) for home and space heating, Passive Solar Cooling
(PSC) and "Daylighting".
PSH
can be used to meet wholly or partially the heating requirements at home while
PSC
achieves cooling during the summer months.
PSH
design collects and stores thermal energy from direct
sunlight.
PSC
minimizes the effects of solar
radiation through shading or generating air flows with convection
ventilation. Daylighting
refers to the use of light from Sun to meet some of the lighting requirements at
home.
Passive systems are design based involving
the
use of the building components to collect, store and
redistribute
solar heat
gains. This
is achieved through proper
materials'
selection,
sizing and orientation of
windows, doors and other building
components.
Active Systems
involve a collector that collects sunlight and "converts
the light to heat" to provide
domestic hot water, pool heating and space
heating. Another active system uses photovoltaic cells (PVC)
to obtain light directly from Sun and use it
to provide electricity or to power electric devices at home or in
commercial settings. A PVC often require a
battery to store DC currents coming from the Sun through the
PVC and an inverter to convert the DC to the
AC currents required for electricity supply and for powering
electric devices.
The other uses to which Solar Energy has
been put include: Agricultural purposes (drying, power supply for
equipment, running greenhouses etc), water desalination
and disinfection, and Solar Vehicles.
Related Subjects:
|
