Technological advances will mean cladding is no longer just about function and aesthetics. Think cooling, power generation and communication
Expect to see green walls brightening up the streetscape in 2019. As with green roofs, vertical planting on walls can improve air purity, reduce storm water runoff, insulate from noise and reduce thermal loading, which means less CO2 emissions and lower heating and cooling bills.
But living wall manufacturer Biotecture has taken the concept a stage further, teaming up with sustainability consultant Max Fordham to integrate an experimental cooling system into a green wall. Its Biowall cladding system incorporates a layer of plants grown in super-absorbent rockwool. The plants are watered and fed via a computerised hydroponic irrigation system programmed to deliver precise amounts of water to the wall.
A test system to be trialed at David Morley Architects’ (DMA) Clerkenwell office in London this summer will help to reduce the need for air conditioning in the IT server room. A ‘reverse’ radiator in the server room will absorb heat and channel it through a pipe beneath the green wall. The water in the pipe is then cooled by the plants and irrigation system.
‘It’s a closed-loop system and constantly removes heat. The water goes out at about 23 degrees and comes back in at about 17 degrees,’ says Richard Sabin, co-director of Biotecture. ‘Irrigation makes the green wall very effective as a heat exchanger because the pipes are always running through a wet medium, which has a slightly lower temperature, which means a larger heat differential.’
Flexipix brings buildings to life
It might sound like a scene from the sci-fi movie Minority Report, but facades that interact and communicate with humans are only a small step away, according to Armand Terruli, senior project manager at ETFE specialist Vector Foiltec.
The company has developed a technology called Flexipix, which integrates curtains of LED lights into a transparent ETFE cushion. The combination allows videos and images to be displayed directly on the surface of large buildings. ‘Soon we’ll have the definition of a laptop screen on the side of a building, and from there it’s a small step to communicative skins,’ says Terruli.
‘Once the skin can display the information, it’s just a case of perfecting the interface with sensor technology, which already works. Data from pressure sensors that react to touch, movement, or temperature can be fed into the building display, which reacts with images, colours or even movement using pneumatics.’
Facades could even tailor specific information to individuals based on data transmitted and received from gadgets like mobile phones or watches. ‘This is already happening on some digital billboards,’ adds Terruli. ‘It’s like a different sort of transcendence or consciousness.’ Okay, we’ve lost you there.
Power of plants creates electricity
What if building facades could recreate plant photosynthesis to generate electricity? That’s the question being asked at Corus, which has joined Australian company Dyesol to develop metal cladding products that incorporate dye-sensitised cell photovoltaics.
The objective is to develop a product integrated into a colour-coated steel cladding system that can operate for up to 25 years.
Dye sensitised solar cells mimic the photosynthesis process of plants. When exposed to light, a special dye in the cells generates electrons, which enter the conduction band of a high-surface-area semi-conductor film, then move through an external circuit which converts the sunlight to electricity.
The semi-conductor is based on a nano-porous titania structure, the surface area of which is 1,000 times greater than the area of the cell, making it an extremely efficient light sponge. Titania is one of the world’s most widely used materials and is found in paint, sunscreen and toothpaste.