Renewable Energy World.com
New reports are showing that the old style solar flat plate collector is on the decline since 2009 AND that solar central heating installations are becoming more important than just solar hot water.
The flat plate collector can trace its origins to 1891 (No, not 1981 but 1891) when it was originally developed and today’s current flat plate collectors are attributed to the 1950′s developed by Hottel and Whillier. Very little innovation has occurred with flat plate collectors since. They are simply a box with a glass lid and some pipes inside. There are still many flat plate collectors made from wood for sale today, (believe it or not)
1891 — Baltimore inventor Clarence Kemp (“the father of solar energy in the U.S.”) patents first commercial Climax Solar Water Heater. By 1910, the Climax had competition, especially from the Night and Day solar hot water company, which used a secondary loop from the collector to a water tank. By 1920, over 5,000 Night and Day heaters had been sold in California At the same time, a boom in solar hot water heaters started in Florida, where electricity was a very expensive competitor. About 15,000 units were sold by 1937. (Butt & Perlin)
The latest report from the IEA (International Energy Agency), highlight that 2009 figures show another ground breaking increase in solar thermal by 36.5 GWth, an increase of approx 25% in global solar hot water collectors, BUT the good news is for innovative newer solar thermal vacuum panels from company’s who have been investing heavily in R&D. These technologies are all using vacuum based designs and these technologies accounted for most of the world growth at a staggering 35%.
Flat Plate collector growth was stagnant at a little over 2% in 2009 and although the IEA figures do not include 2010, all the evidence suggests that this pattern continued in 2010 as well.
This means that many of the flat plate manufacturers in Europe faced a challenging economic year in 2009, and again in 2010, while innovative vacuum based collector manufacturers growth is booming.
Another clear sign in the market is coming from Austria and Germany with Solar Central Heating becoming the norm. These specialised applications need the highest performance and newest innovative solar panel technologies. This may well be an indication of why there is a dramatic shift. It is well known that flat plates work fine if you live in a climate with good blue sky sunshine. The shift to all year solar thermal systems could lead to the complete demis of the outdated flat plate collector. (although a 120 year history for the solar flat plate has been a significant lifespan)
According to the Solar Heat Worldwide report; Austria who has always led the original solar thermal market had 45% of its solar installations in 2009 installed as solar central heating & hot water versus 45% hot water only. Germany had 35% of its new installations in 2009 installed as solar central heating & hot water systems. This represents HUGE growth in these more complex and challenging systems and may account for the dominance of more powerful solar vacuum panel technologies.

Top 10 world markets for solar hot water panels – 2009.
One major installer group which specialises in Solar central heating & hot water systems commented:
“we saw the writing on the wall in 2009 when we stopped installing flat plates. They simply were no competition for solar vacuum collectors. Since then, we will now only work with a hand full of vacuum manufacturers as even some vacuum collectors, mainly heat pipe ones are completely unpredictable for performance and the construction materials are questionable. There are some newer solar vacuum panels from company’s who have invested heavily in R&D programs and they are leading the way in performance. 50% of our work is now combination solar central heating & hot water systems so we can no longer guess about performance, we need proof because our customers are much better informed and they demand it”.
ESTIF President, Robin Welling said: The solar industry has experienced the full impact of the financial crisis. we expected to get some benefit of the combined implementation of the binding renewable targets and higher energy performance standards – but this process is only beginning.
In Summary, There is a clear message coming from the data just released, with a history of over 100 years, the solar flat plate collector is in decline and has struggled to successfully move into markets where weather is poorer versus the initial sunny summer markets like Austria and Germany. These all year round solar central heating applications “even in Germany” need real performance, not smoke and mirrors, and ironically, as these sunny markets move to solar central heating and hot water systems, they are now turning their back on the old type solar flat plate collector in favour of newer R&D backed solar vacuum collectors to deliver this “all year requirement” expected from future installations.

If you still drove a car designed in the 1950′s, this is what you would be driving.
If you still drove a car designed in 1891, this is what you would be
driving a Peugeot Type 3 Quadricycle.