GRANADILLA DE ABONA, Tuesday March 16 2010
FROM recycling your rubbish to cycling to work, in recent years we have been urged to make myriad small changes to our lifestyles to save the world from the supposedly cataclysmic threat of climate change.
by JAMES TWEEDIE
But how much can we really contribute towards cutting global greenhouse gas emissions by using low-energy light bulbs and putting our potato peelings in a compost bin? Can we really have a carbon-neutral lifestyle?
The Canary Islands have become something of a laboratory for renewable energy over the last two decades. Tenerife has three wind farms with three more in the pipeline, and a photo-electric solar panels are now assembled at a factory on the island, a welcome diversification from the crisis-hit tourism economy.
Tenerife's Renewable Energy and Technological Institute (ITER) opened its new bioclimatic homes exhibit at its headquarters in the Granadilla industrial estate on March 19. The 14-year long project attracted designs by 397 leading architects from 38 countries, of which 25 were chosen to be built.
ITER is 80 per cent owned by Tenerife's Cabildo government and is a pet project of current Cabildo president and engineer Ricardo Melchior.
ITER is 80 per cent owned by Tenerife's Cabildo government and is a pet project of current Cabildo president and engineer Ricardo Melchior.
Bioclimatic homes use a variety of high- and low-technology design features to actually produce more energy than they use.
Photo-electric and solar water heating panels are obvious solutions to this problem, but thick walls for insulation, large opening windows to trap or release the sun's heat, ventilation chambers and even the positioning and orientation of the building – exploiting natural terrain – are utilised to good effect.
Speaking at the opening ceremony, World Council for Renewable Energy (WCRE) chairman Dr Wolfgang Palz insisted that bioclimatic construction costs no more than as conventional building, but that "vested interests" were preventing the concept from catching on as fast as it should.
I had the opportunity to look around the homes a few days before the official opening with visit organiser and guide José Ignacio Fernandez.
Speaking at the opening ceremony, World Council for Renewable Energy (WCRE) chairman Dr Wolfgang Palz insisted that bioclimatic construction costs no more than as conventional building, but that "vested interests" were preventing the concept from catching on as fast as it should.
I had the opportunity to look around the homes a few days before the official opening with visit organiser and guide José Ignacio Fernandez.
Each house has its own name. The first one we visit is La Geria, named after the traditional method of construction from the Canarian island of Lanzarote used in its pale grey volcanic ash walls. All the materials used in the building's construction were locally-sourced.
The design by a team of six Spanish architects won the first prize in ITER's bioclimatic homes competition.
Geria walls are used to protect grape vines from the sun, utilising the natural insulating properties of the ash. However, the material in construction is now prohibited from building use. It is easy to see why – it crumbles to the touch.
The interior of the single-story building has wooden floors, walls and slatted sliding doors. There are air vents between all the rooms and large air chambers beneath the floor and above the ceiling.
Floor-to-ceiling glazing on both the southern front side and northern rear of the house allow future occupants to control airflow and regulate temperature.
This open ventilation system sweeps hot air out of the house which would otherwise accumulate, rise and become trapped in the ceiling spaces.
The front of the house has a slatted veranda which shades it from the noon-day sun baut allows air to circulate, while the sheltered rear patio is designed to stay cool throughout the day.
The solar thermal panels on the roof heat water, which is stored in an old-fashioned tank on the roof. Ignacio explains that in a cold climate the hot water tank would be placed under the floor, where it would help heat the house by convection.
The panels consist of an array of vertical copper tubes connecting horizontal feed and drain tubes at the bottom and top, between two sheets of glass. Set at the best angle to catch the sun, and located on the dry south coast of Tenerife – 28 degrees north of the equator – each house needs just two or three square metres of these panels.
Like all the homes in the facility, La Geria is connected to Tenerife's electricity grid. Ignacio explains that this is more efficient, economical and environmentally-friendly than trying to make them independent of other forms of power.
Each home would need six to twelve large batteries to store electricity overnight, taking up a room to themselves. The batteries are expensive and polluting to produce and dispose of.
In fact the homes generate more electricity for the grid than they use, which ITER sells to electricity company Unelco Endesa.
The next home that we visit is El RÃo (The River) by French architect Morel Cedric, so called for the shallow flowing water channel which runs through its high central living room-cum-patio, the glazed sides of which can be opened out for ventilation of shuttered for shade.
The bedrooms and bathrooms are dug out of a rise in the ground on one side of the house. Illumination comes from skylights, light fittings with five-watt low-energy bulbs and white-painted walls to maximise reflection.
We found local painter and decorator Rob Hooper and two of his craftsmen putting the finishing touches to the dwelling before Friday's grand opening.
Rob has been working on the bioclimatic homes project for three-and-a-half years. He tells me: “It's amazing. There are some incredible designs here. The most intriguing thing is how they use the wind for cooling and ventilation.”
Next stop on the tour is the Italian-designed and Roman-influenced El Caminito (the little way).
The first striking feature of this building are the square brick columns that stand like monoliths around the front yard, which provide shade from the sun without blocking the sea view.
The second is the wide concrete air duct which runs through the house from end to end, providing cooling. Ignacio admits that while this is far from his favourite house, it is the best acclimatised.
Las Bóvedas (The Vaults) by Spanish architect Jaime Navascues Lacourly is also dug into the arid terrain of Granadilla for shelter. Steps lead down to its sunken patio, while its roof sprouts shining metal chimneys topped with spinning 'dynamic ventilators' – by no means a space-aged technology – which draw hot air from the interior.
The construction is simple: white-painted concrete with little or no no expensive and hard-to-maintain stone and wood.
Ingnacio says: “Not many people like this house, but I just love it.”
The first two-story dwelling we see is the angular aneclectic El Dispositivo (The Device), designed by Venezuelans Pablo La Roche, Ignacio de Oteiza y Francisco Mustieles.
The two long, narrow floors are set at an acute angle to one another, with a thick free-standing wall giving shelter on the windward side. The wall has many narrow, vertical ventilation slits. Those level with the upper story are set with opening windows.
Like El RÃo, this house also uses a water feature in the form of a shallow square pool outside the ground floor kitchen. The function is the same – to keep the place cool – but Ignacio comments: “I bet if you had kids you'd know where to find them.”
What this house lacks is privacy. The two-bedroom top floor is open-plan with no internal doors, and a large grill set in the floor to give anyone in the kitchen a good view up your dressing-gown to go with their morning coffee.
Practical Technology?
I ask Ignacio if the technology used in ITER's experimental homes could be applied in existing buildings and urban areas.
He laughs: “That is a political question, my friend.
“You would need to design the whole city to bioclimatic principles,” he says. “It is difficult to place this technology on old buildings. You will destroy the beauty of he building, or if not you may affect the infrastructure – gas, electricity supply.
“Old buildings have no space for solar thermal installations. The pipes would have to run through communal areas.”
He adds that the technology is expensive, and that people are not always willing to pay extra.
However, planning regulations mean that new buildings in the Canaries must be ready to fit solar panels.
For those of you who cannot wait for bioclimatic houses to be built in your town, ITER is planning to rent the 25 homes to tourists and business travellers.
Renewable Future
While Tenerife's electricity grid is partly powered by the 40-metre diameter wind turbines which tower over the bioclimatic homes like the giants of Don Quixote's imagination, 90 per cent of the island's electricity comes from the oil-fired power station next door to the ITER facility, making the island vulnerable to fluctuations in the prices of imported petroleum.
This is in stark contrast with mainland Spain, which generates barely 3 per cent of its electricity from oil through the use of nuclear and hydro-electric power. The latter is not an option here – gathering enough fresh water for domestic and business supply is a major engineering problem in the arid Canaries.
What the Canaries does have is year-round sunshine and the Atlantic trade winds. Ignacio points out that the wind turbines installed at Granadilla can generate 650 kilowatts of electricity each, while the latest designs produce 6 megawatts – almost six times as much – from a slightly larger rotor.
“We have great possibilities for wind energy” he says. “Why don't we have the windmills?”
Geothermal heat seems to be another obvious solution in the volcanic Canary Islands, but Ignacio explains that the hard volcanic basalt bedrock is expensive to drill through.
Wave (or tidal) energy also looks like a good idea out here in the midst of the Atlantic Ocean, but ITER has no plans to make use of it.
Ignacio points out that the density – and therefore energy content – of sea water is 800 times that of the air which turns ITER's wind turbines.
“We have to get involved with sea energy,” he says. “I don't know if it would be economic, but we should have that technology for future years.”
Comments
My favourite invention (my own, of course) is the solar-Stirling-engine-pumped secondary water circuit, controlled by thermostats, that can automatically direct heat wherever it is needed, and could probably operate a fridge and air-conditioners, too. That would mean much thinner, lighter solar heat-collectors, because the bulk hot water would not have to be hauled up to the roof and heated directly.
The heat collectors could be cheap, small, easy to transport and capable of being clipped together to create any appropriate capacity. Such a system could much more easily be installed in existing buildings, because of the lightness of the collectors and because the tubes would be flexible small-bore, and because the existing plumbing circuits would not be much affected, if at all.
Those "dynamic ventilators" are used in South Africa as components of "Ventilated Improved Pit-latrines" (VIPs) so they always make me think of bad smells.
Speaking of which, there is very little of the "bio" in these "bioclimate" homes. Were you deliberately avoiding the subject? Or is it not done to mention such things in Spain? How does it work, up there on the volcanic rock?
I don't know why they are called bio-climatic. There don't seem to be any biological solutions. El Caminito has a 'vegetable' garden at the back, but that's just a way of saying that you can grow food in your garden if you want.
I think the houses are connected to the conventional water and sewage systems, so there are no 'organic' earth closets or cess-pits stinking the place up.
Have you patented your invention? Why don't you post it up here. The fiancée of a classmate of mine used to work for the company which installed the solar water heaters at Granadilla.
South Africa is a big place. Hasn't anyone thought of covering the veldt with these things?
There are businesses starting up here to sell and fit solar panels to homes. But that is another small-scale individual solution. I think the big 'eolic parks' or wind farms are a better bet, but the two things could be complementary.
It doesn't make sense to me to have tons of water sitting on the roof. I see these things around in SA and they are ugly, and expensive. You want to bring the heat down to the water, and to other locations.
It doesn't make sense to me to make electricity so as to do things that solar heat can do direct, like shifting free heat from the sun to a different location.
It's a funny thing but technology doesn't travel easily. The central heating kit and the theory that goes with it seems to be unknown here in SA, although the winter is quite rigorous enough to make it worthwhile. In the highveld, the winter is the sunniest time. You don't need a gas-fired boiler when your roof is taking hundreds of kilowatts of buckshee heat. But you need to route your heat in the same smart ways that people do with the boiler-generated heat in the North, and not just crudely expose your bath-water to the sun.
SA has lots of sun but very little wind. There are a couple of wind farms in the Western Cape, but I don't think wind power will ever be big in the country as a whole.
But in these Tenerife houses they have got the summer house-cooling side quite well sussed using air circulation, and you can do even better if you build a bit of a tower to fetch down cool air, middle-eastern style.
Good building design is always a mixture of technologies.
One of the houses there, which I didn't see inside and so didn't feature, has some kind of tower structure.
There is also a British two-story design which puts the bedrooms downstairs where there is less rising hot air, and the kitchen and living room upstairs to better enjoy the view.