Thermal solar

Using heat from the sun

Thermal solar technology uses the sun to heat water or air to produce heat or electricity.

Examples of thermal solar are hot water heating and food drying.

Newer technologies are experimenting with ways of using heat from the sun to generate electricity.

Solar hot water

Solar hot water systems work with your existing gas or electric hot water service. Water is heated in a rooftop solar collector and piped into your hot water service. There is no need to worry on cloudy days, because your hot water service will ‘top up’ the heat by using gas and electricity, to the desired level – so you’ll always have water at the right temperature.

The solar collector is usually located on the roof facing the sun.
Sunlight heats an absorber plate in the collector and this heats the water running through tubes inside the collector.
The heated water is pumped or moved by gravity into your gas or electric service tank.

Solar water heaters use much less electricity or gas to produce the hot water you normally use. Typically, solar can provide about 60% of the energy needed to provide household hot water.

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Thermal solar in the future

There are many experimental thermal solar technologies that generate intense heat or drive power plants.

Solar concentrators use mirrors or reflectors that focus the sun's rays to produce maximum heat, which then creates steam that drives a generating turbine (similar to a typical gas or coal fired generator).

Solar chimneys or towers are another experimental use of thermal solar. Heated air rises in the chimney turning a mill. The mill then turns a generator, producing electricity.

Solar desalination

Solar energy can be used to power desalination or water purification.

Solar desalinisation, purification and pasteurisation all use the sun to heat water.

Using the sun to take the salt out of water is called ‘solar humidification’. This process mimics the natural water cycle i.e. heat evaporates salty water which then condenses without the impurities (salt) as water droplets.

Thermal solar investigations:

Investigation 1: Black, white and silver: which reflects and which collects?
Investigation 2: Solar pasteuriser made from recycled materials

Learn about: Passive solar, Photovoltaic cells