Unbeatable results: Over 80 percent more energy

At a solar irradiation of 400 Watts per square meter, an ambient temperature of 10 °C as well as a supply temperature of 70 °C the CPC evacuated tube collector puts out 88 % more energy than a very good flat plate collector.

Note:

400 Watts correspond approximately with the mean annual solar irradiation in Middle Europe.
Referring the collector power output to higher irradiation levels e.g. 800 Watts may look better but does not comply with our climate conditions.

However the flat plate collector is quite an option for temperature rises up to 30 K.

For providing process heat, only the CPC tube collector is really economical. The CPC tube collector achieves remarkably higher usable operating temperatures. Furthermore the CPC evacuated tube is the only option e.g for heating support or process heat with supply temperature of more than 50 K above ambient temperature.

At a collector temperature of 60°C and an ambient temperature of 10°C the comparison clearly shows:

The outer surface of the CPC tube collector is cold (blue), while the best flat plate collector shows severe losses (red).

On the left hand side in the figure: flat plate collector (red)
On the right hand side in the figure: tube collector (blue)

collector comparision