Large Scale Solar Water Heating

In the UK we are used to solar water heating panels on our roofs, with an average size of about 2 square meters, just to contribute a part of the domestic hot water of a single household. Over the next couple of blogs I want to write about large scale solar hot water systems, from a few hundred to tens of thousands of square meters, now rapidly being deployed in Europe, with a few elsewhere in the world, but sadly none yet in the UK, despite the fact that they would work very well in our climate. These systems can be used to produce domestic hot water, central heating and even air conditioning in summer for groups of just a few households to towns with thousands of buildings. Hot water is fed into a district heat main with a central storage tank, which if of sufficient size and insulation can store the summer’s heat to meet a large part of the winter heating requirement of whole communities.
The photo above shows an apartment block, part of the 61 residential units that make up the Gneis Moos development in suburban Salzburg. These buildings are super-insulated to passive house standards, with plenty of south facing glass for passive solar gain, a 410m2 solar thermal roof feeding hot water into a 100,000 litre heat storage tank. Already ten years old this still represents cutting edge energy efficient architecture and just the sort of thing we should be doing in the UK. ( More about Gneis Moos see,
Christian Holter and his company SOLID Solar designed and built the solar roof at Gneis Moos and have since designed many more including the impressive swimming centre for the 2008 Chinese Olympics ( and retrofitting a huge bank in Lisbon for solar powered air conditioning, and about 200 other projects with solar collection areas greater than 100 m2, and are now increasingly designing solar roofs of over 1,000 m2!