There are 2 Types
of Passive Solar Hot Water Systems
Thermosiphon:
This operates on the principal that hot water has
a lower density than cold.
When
water in the collector is heated, it becomes less dense and
rises to
the top of
the storage
tank.
The denser cool water from the bottom of the tank
flows into the solar collector. In
these systems, the storage containers are placed above
the
collector panels.

Integral-collector storage
system:
This type of passive solar water heater relies
on
the
tendency of gravity, for colder
water in
the existing tank below to naturally circulate as it is
heated. They contain no electrical
components. These solar collectors are suited for areas
where
temperatures rarely go below freezing. They are
used in
households with significant daytime and evening hot-water needs; but
they do not work well in households with predominantly morning
draws,
because they
lose most of the collected energy overnight, thus activating
your electric back-up element.
