Evacuated Tube Solar Hot Water Systems 

Hills_solar_esteem_Solar-TuEvacuated tubes solar hot water systems were pioneered at the University of Sydney, and University of NSW. Sydney University began work on evacuated tube technology in 1975, and by 1980, the first ‘Sydney tubes’ were in commercial production in Japan. So, far from being ‘new technology’, evacuated tubes have been on the market for over 30 years in both Japan and Europe. But ‘what’s in it’ for customers? What are the advantages of evacuated tube systems? 


The first major advantage is one of efficiency. With a flate plate system, the sun is only perpendicular to the plate at 12 midday.free-quote-solar-hot-water

As you move towards sunrise or sunset, the angle of the sun to the plate increases, and the efficiency decreases. With evacuated tubes, the round shape means that the sun is ‘square-on’ to the tube all day, increasing efficiency.

Higher efficiency means lower running cost. 

Presentation on the Development of Evacuated Tubes.

The second major advantage is one of maintenance. Many flat plate systems, particularly the ones used in colder areas, use glycol to prevent freezing up. Over time, the glycol becomes adulterated with water, and requires replacing.

evacuated-tube-solar-cutawayAnother major advantage is that of service cost. If something goes wrong with one of your flat plates, it’s an expensive job to replace it, and you’ve lost a large proportion (or all) of your hot water until it gets fixed. With evacuated tubes, each one is an individual collector. If one tube gets damaged, all the others keep working just fine. Think of 30 lightglobes working- if one goes out, the other 29 do the job just fine. And just like a lightglobe, the individual evacuated tubes can be taken out and replaced- by anyone who can safely get up on the roof. We’ve mentioned cost earlier in the paragraph. The cost of a replacement evacuated tube, that you can replace yourself, is usually in the range of $35-$65. Replacing a flat plate will cost many hundreds of dollars, and must be done by a technician. 

The last major advantage of evacuated tubes is that, in most systems, there is no water in the tubes.

The problems experienced by poorly designed, incorrectly specified, or failing flat plates, when temperaures drop below freezing, simply aren’t an issue with evacuated tubes.

The fact that there is no liquid in the tubes means that there is no heat lost to the atmosphere at night, as can happen with flat plate systems.

In Australia, two superior brands of evacuated tube solar hot water systems are produced by Solargain and Apricus Solar.. Both are featured on this website- just follow the links. They are well worth researching, and getting quotes on. 


 Posted on : November 12, 2015