Power house

The bright green façade of the Sustainable Building Envelope Centre (SBEC) certainly stands out next to the traditional industrial buildings that populate Deeside, North Wales. Among the steel works, gas turbines and paper mills, Tata Steel and its partners are turning cutting-edge research into innovative products that could help turn buildings into power stations.

Buildings account for around 40 per cent of carbon emissions in the UK, according to the Carbon Trust. The idea behind SBEC – a £6.5m joint venture between industry and academia and part funded by the Welsh government – is that buildings should be seen as a resource for energy, and that traditional materials such as steel can be used to harness this power.

’Roofs and walls are assets, and instead of leaking energy out they should be doing the reverse,’ said SBEC director Daniel Pillai. ’Because energy’s been very cheap in the past, we’ve behaved like fat mammals, gorging ourselves with a lot of energy just to keep ourselves warm. But the lizard is an illustration showing [that] if you’re smart you come out and lie in the sun and you don’t have to eat quite as much.’

Employing 18 full-time staff at its retrofitted warehouse headquarters, SBEC’s role is to commercialise methods of using building materials to collect, store and release energy. One day we could see roof panels containing batteries with solar cells painted on top and LED lighting printed onto the ceiling below. And these technologies all have the potential to be made in Britain.

Buildings should be seen as a resource for energy, and materials such as steel can be used to harness power

Some of this research comes from previous projects involving Tata and partners in another of the centre’s co-funders, Wales’s Low Carbon Research Institute. But there’s another dedicated programme that feeds directly into SBEC: the Sustainable Product Engineering Centre for Innovative Functional Industrial Coatings, also known as SPECIFIC.

WATCH OUR VIDEO REPORT ON THE SBEC HERE

Led by Swansea University, SPECIFIC’s role is to research technologies at an earlier stage of development than SBEC, with a focus on active coatings – paints that can do something such as capture or release energy or even purify water. The team has chosen 10 suggestions out of 200 possible coating ideas and plans to whittle these down to two or three to produce on a pilot line.

’Our work fits in very nicely in terms of a philosophy with SBEC,’ said SPECIFIC research director Prof David Worsley. ’While our remit is to produce these materials at a scale you can use them, SBEC has the enormous advantage that it can turn our flat sheets into potential components or items that you can put on a building to test them out.’ This makes it easier to demonstrate and explain to potential industry partners for feedback – a key part of the strategy for developing technologies.

SBEC opened in March 2011 and is already preparing to launch its two products onto the market by the end of the year. One is an adhesive system that bonds lightweight photovoltaic (PV) modules directly onto steel roofs, in order to reduce the load on the building and cut the cost of installation – which can more than double the price of solar panels. The next step will come from building-integrated PVs, meaning the building materials themselves generate power. SBEC is now piloting a form of dye-sensitised PV where 16 layers of substances, including titanium and polymers, are printed and painted onto a steel surface to create a layer of electricity-producing material just 100 microns thick. It’s also investigating thermoelectric generators, where the sun’s heat creates a voltage due to the temperature difference between two materials in the roof.

The second product uses a version of a technology that dates back to the 1990s: transpired solar collectors (TSCs), which are essentially perforated sheets of metal that sit on a building’s outer walls and draw in air heated by the sun. Although it’s a simple idea, with SBEC’s improvements and management system the units have reduced the gas heating bill of one trial industrial building by 49 per cent. They could be combined with PV panels on the roof to draw heat away from the solar modules and make them run more efficiently, and the SPECIFIC team is looking at coatings to improve them even further.

But the technology also highlights another problem – storage, which is a crucial part of any efficient renewable energy system. ’The strongest point [about TSCs] is that they’re capable of converting 75 per cent of the sun’s energy, which is highly efficient given that PV is only 15 per cent,’ said Pillai. ’The downside is that what it delivers is warm air, which is a low-grade heat, perfect for heating spaces, but there’s not much else you can do with it. If you can somehow dump that heat and vary the rate of reaction on the output to get all the temperatures that we want then you really are onto a winner.’

Phase-changing materials and heat pumps that move hot and cold water about the building are essential for daily thermal storage, and for electricity the team is looking at effectively stretching out a lithium-ion battery within the roof and walls. But the real trick will be cracking seasonal storage. Rather than using underground water tanks that gradually lose their energy, SBEC is looking at a chemical-based system. ’If that were to collect all the excess heat we throw out in the summer and capture that in a vat, [we could] release it in the winter,’ said Pillai.

The final aspect of the work is in releasing energy via printed coatings that produce light and heat when a current is passed through them, and this is where SPECIFIC is concentrating most of its efforts.

Of course, developing these technologies in a research centre is one thing, but the aim of SPECIFIC and SBEC’s work is to produce practical ways of reducing net energy use. ’It’s about delivering solutions rather than individual products or technologies and the challenge designers face is how does the system perform as a whole?’ said Pillai. ’What we’re trying to do here is link systems that work efficiently to certain building types, and then ultimately learn from that process and develop design tools and software packages that will enable other design teams to adopt these technologies.’

Part of this means seeking cost-effective manufacturing processes and materials safe enough to meet strict building regulations and working with industry to hone in on and develop the best ideas – crucial because part of SBEC’s role is to create products for manufacture in Britain that will benefit firms all along the supply and installation chain. ’Certainly for the first two years, most of the manufacturing will be done in the UK,’ said Pillai. ’Some of the added value as we roll out will be done on the Continent, but the manufacturing of the raw materials and the pre-finished materials will be in the UK.’

“Certainly for the first two years, most of the manufacturing will be carried out in the UK”

DANIEL PILLAI, SBEC

Cost, of course, is also vital. But Pillai said no product would be launched that wasn’t economically viable for customers. ’[TSCs], as an example, have a payback of three to six years without any subsidies, so it is highly viable. Like any other investment, I think that a three- to six-year payback for a very risk-free technology is highly attractive.’

What SBEC has done at Deeside with its striking retrofitted building is a good metaphor what it hopes to do for construction manufacturing: turn products from a carbon-intensive industry into something that can help reduce emissions. And in the process, SBEC could do something vital for economic recovery by proving Britain can commercialise its ideas.