Contrary to what some people believe we have seen solar water heating system appear long time ago. As technology did advance they ended up becoming really efficient. Nowadays the efficiency of an evacutated tube solar water heater stands somewhere over 90%. Basically this means that the sun’s energy is landing on the surface and is converted to heat at around 90%. When we compare the costs associated when generating energy we are faced with a much lower cost than regular sources.
Evacuated Tubes of Vacuum tubes are usually made out of glass. In most cases one double wall system is used based on Pyrex. Glass noticed in inner tubes is coated in most cases on its outer surface with the use of absorbing coating. Inside all tubes air is removed in order to create one vacuum. Right in the middle of the tubes you will find copper heat pipes. Such a sealed heat pipe is good as it also includes in most possible cases anti freeze liquid and can help in absorbing infra red radiation better.
The one big advantage that appears with the use of evacuated tubes in solar water heating stands in the fact that these also work when we are faced with cold weather. Vacuums are used to make sure that the tubes are not cooled too much thanks to the interference of the ambient temperature.
Also, thanks to evacuated tube systems you can also take advantage of the little sun power that we see during winter. In different cases you will be happy to know that the water can even reach 50 degrees if you use your solar water heater system.
The main reason why evacuated tubes were not popular a few years ago was the fact that they were not really available for anyone. At first we only saw them in different commercial equipments, which were quite expensive and not affordable by regular people that wanted to use them. Nowadays this type of tubes is available and you need to know that they are actually recommended. The solar water system will become much more efficient if it also comes with included good evacuated tubes.