Thursday, 3 March 2011

EcoBuild fires the imagination

I headed over to the EcoBuild exhibition in Docklands yesterday.  The Travelcard from Windsor is now valid on the Docklands Light Railway, so it's quick and cheap to travel right to the door of the ExCel centre.  There were well over 2,000 exhibitors, so it's impossible to see everything in a few hours but I was able to pick out a few highlights.

There is a boom in flat roof technologies!  Many commercial buildings have load-bearing roofs that are unused and the Government's Feed-In Tariffs are making solar PV an attractive option for buisnesses and home-owners alike.  What's new is the range of alternatives to traditional silicon panels mounted on A-frames.  Lots of thin film solar technologies have now reached the market.  Producing fewer watts per square metre, meaning larger panels, thin film photovoltaics are also cheaper to buy than the same generating capacity of crystalline panels.  Moreover, they harvest a wider spectrum of radiant energy and so are more effective in overcast conditions - quite well suited to our climate.  Being thin, cheap and, in many cases, flexible, they can simply be glued onto roofing decks, facing straight up.  The most attractive design was from US company, Solyndra.   Designed to simply be placed over large roof areas, each flat panel has many horizontal photovoltaic rods and is shaped like a car roofrack.  The advantages are that the individual tubes are fixed at the correct angle for optimum power generation whilst the flat racks let wind and rain through, meaning that they don't need bolts or ballast to keep them in place in stormy weather.  Then there were the integrated solar PV and thermal panels, generating electricity and hot water, the advantage being that the water flow keeps the solar panels at the low temperatures needed for optimum generating efficiency.  Most confusing, there was even a solar thermal panel running on refrigerant gases that is claimed to generate heat in the dark of night as well as in the daylight!  I think that, in reality, this is an air-source heat pump which is boosted by the sun's warmth during the day.

Beyond solar panels, the most attractive designs were of green roof technologies, bringing biodiversity back to 'urban deserts' and helping to clean up the air we breathe in our towns and cities.  The most beautiful display was from Blackdown green roofs of Somerset who had planted so many spring flowers into their flowing sedum roof that it looked like an Alpine meadow and would not have been out of place at Chelsea.

Under all these working rooftops were a bewildering array of structural, insulating and cladding materials together with hyper-efficient doors and windows.  For green plumbing and heating, there were oodles of heat pump systems (these use a little electricity to harvest a lot of renewable energy) and new, high-efficiency radiators that run at the lower water temperatures provided by heat pumps or even our current, gas-fired condensing boilers when operating at their most efficient.  To save electricity at home, the brilliant VPhase system retails at around £200 plus fitting.  This simple fit-and-forget technology is widely employed in commercial buildings.  VPhase is the domestic version that has been proven in large-scale trials over the last five years and will cut the average home's electricity usage by 8 - 10%.

Surprisingly few LED lighting suppliers were exhibiting but the architectural lights on show from Deltalight were simply mind-blowing.  Their secret is the tiniest LED chips, giving incredibly sharp edges to the light thrown from these low-power sources.  The only downside was the price ...

If I had the money and the land, I would love to take the best of  these technologies and build a sustainable home needing no fossil fuel energy for heating and lighting.  That's the point of these exhibitions - to make us dream!