How split system solar hot water works
Split system Solar Hot Water has the tank at ground level with only the panels on the roof.
Because the panels are above the tank, thermosiphon will not work.
Therefore a pump is used to move the water through the panels. The pump is activated by a computer (called a controller) which senses heat as described below.
If there is not enough heat in the Sun on a particular day (extended cloudy periods and during Winter) a booster is used to top up the heat.
Most solar hot water systems use electricity to boost, however gas boosted systems are also available
How the Sun heats water in a split system
The solar panels (1) collect heat from the Sun.
The hot sensor (2) sends a signal to the controller (3) that heat is available which activates the pump.
The pump circulates cold water from bottom of tank to the panels (4) which heats the water.
The hot water is pushed from panels (5) back to tank.
Benefits of split system solar hot water are:
Less weight on the roof
Doesn't create shade on solar power panels