The use of solar energy in recent years had reached a remarkable edge. The continuous research for analternative power source due to the perceived scarcity of fuel fossils isits driving force. It had become evenmore popular as the cost of fossil fuel continues to rise. Of all the renewable sources of energy available,solar energy is the most abundant one and is available in both direct as well as indirect forms. Solar energy
applications
were
divided
mainly
into
two
categories:
the
first
is
the
direct
conversion
to
electricity
using
solar
cells
(electrical
applications).
The
second
is
the
thermal
applications.
The
latter
include
solar
heating,
solar
cooling,
solar
drying,
solar
cooking,
solar
ponds,
solar
distillation,
solar
furnaces,
solar
thermal
power
generation,
solar
water
heating,
solar
air
heating,
etc.
Detailed
description,
fundamentals
and
previous
work
performed
on
solar
dryers
and
solar
air
heaters,
as
the
vital
element
for
the
indirect
and
mixed
modes
of
solar
dryers,
were
presented
in
the
present
review
paper.