Solar Thermal Energy

Solar thermal panels for home use – Either evacuated tubes or flat plate systems, provide hot water to either an existing or more typically a hot water cylinder with an additional solar coil.

Many manufacturers are on the market, and they are now becoming widely available from trade plumber merchants, as well as specialist solar panel suppliers and direct sales organisations.

There are two main types of systems, flat plate and evacuated tubes.

Both solar thermal systems absorb energy from the sun in their collectors, and this is transferred via a pump station and a solar control station to a solar cylinder.

The principal is that whenever there is a temperature differential between the collectors and the bottom of the cylinder, then the pump starts and transfers this energy into the cylinder.

A well designed solar thermal system (evacuated tubes or flat plate), will be able to provide up to 70% of the annual hot water requirement of a household.

The system monitors the temperature in your water tank and typically, when it is lower than that of the panel on your roof the water is pumped out of the roof panel through a heating coil in your hot water tank (the heat exchanger). This, in turn, heats the water in your storage tank. When the weather is cold and or it is dull outside, the pumps remains switched off leaving the your storage tank to be heated by your conventional immersion heater or boiler.

The flat panel collector is the most popular system in the UK, with early examples installed over 25 years ago.

Many manufacturers are on the market, and they are now becoming widely available from trade plumber merchants, as well as specialist solar panel suppliers and direct sales organisations.

A typical solar thermal flat plate collector consists of a special solar glass ,a copper tube which can either snake around the panel or use a manifold top and bottom with tubes between them, a metal backing plate which has an energy absorbing paint applied, and an insulated backing.

Sunlight passed through the solar glass and is trapped inside the panel. Energy is absorbed by the copper tube which usually contains a solution of ethylene glycol. The copper pipe becomes hot and a pump station takes the heat and passes it through a solar coil in a special solar cylinder where it heats up the water in the cylinder. The cooled ethylene glycol mixture returns to the panel and the cycle repeats itself.

The typical components of any flat panel system comprise the solar panel or panels – often called the collectors, a pump, a pressure vessel, a solar control station and a solar cylinder.