Evacuated Tubes - How hot can they get

Part of the process of installing the system is to make sure there is no airlock in the pipes between the pump and the solar collector. If you get an airlock or a blockage it means the fluid cannot flow round the system correctly and the fluid (water and glycol) will sit in the collectors heating up until it boils. Once the airlock is removed the system works perfectly.  This video is just to show you can boil water with an evacuated tube solar collector.

Please note, in the video, only half the tubes are installed in the system while it was bring installed and also this was taken in December 2010 when the outside temperature was ZERO Degrees C.

Evacuated tube collectors are largely un affected by the outside temperature. They will still boil water when the temperature is well below freezing.

 

This is why evacuated tube collectors work so well in cold and cloudy climates.  While the sun is hot you want to capture as much heat as possible to store it so you can use the solar hot water when the sun goes down or you get a few cloudy days when the heat output will be lower.