Solar thermal

Solar thermal

There are many ways of harnessing solar energy. Here we will look at solar thermal in its various forms. Some are more efficient than others, but they are not always the most suitable or the cheapest for the location. The higher the temperature, the more efficient they can be. The Carnot efficiency is the most efficient it is possible to be at a certain temperature difference.

 

Technology °C Concentration ratio Tracking Max possible. Efficiency-Carnot
Flat plate  - hot water 30 – 100 1 - 21%
Evacuated tube - Hot water 90 – 200 1 - 38%
Solar pond 70 – 90 1 - 19%
Solar chimney 20 – 80 1 - 17%
Fresnel reflector technology 260 – 400 8 – 80 One-axis 56%
Parabolic trough 260 – 400 8 – 80 One-axis 56%
Heliostat field + Central receiver 500 – 800 600 – 1000 Two-axis 73%
Dish concentrators 500 – 1200 800 – 8000 Two-axis 80%

Australian solar energy

Australia has more sunlight than any other continent, so solar is one of our main options.

Germany has far less solar energy than us. However they have closed all their coal mines and are dependent on Russian gas so they are very keen to use renewable energy.

They employ 10,000 people making PV cells and have 300,000 people in the renewable industry in 2009.

 

1 MJ = 0.277 kWh.   


MJ 18 19 20 21 22 23 24
kWh 5.0 5.3 5.6 5.8 6.1 6.4 6.7