This is a waterborne bacterium that multiplies at between 40 and 50°C which is the average temperature of water storage including solar. It is potentially fatal if inhaled, for instance when showering. In some countries regulations require a minimum storage temperature of 70°C to be achieved at least once a day. This is the blanket-bombing technique which has a negative impact on the efficiency of the collectors due to scaling problems which arise at over 60°C.
There are other possibly more effective ways of killing the bacteria. Ultraviolet light at high intensity destroys the bacteria's ability to reproduce and is frequently used for water purification. It is still not used in solar thermal systems. Used in combination with ultrasonic waves or anodic oxidation it should remove the source of the problem like biofilms in the pipes. This would be more efficient than achieving a high temperature for part of a day.
Was this article helpful?
The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.