A £6.5 million project to investigate and produce the next generation of low carbon whole building solutions has been opened in north Wales.
The Sustainable Building Envelope Centre (SBEC) at Shotton, Deeside, is a partnership between the Low Carbon Research Institute (LCRI), Tata Steel and the Welsh Assembly Government which over three years will research and monitor solar thermal and photovoltaic technologies and their use together.
Various combinations of technologies will be evaluated, and the solutions arrived at will be relevant not only for new-build, but also for retrofit of large public, industrial or office structures.
The SBEC's director, structural engineer Daniel Pillai, says that the focus on the building envelope (external and internal roofs and walls) is important because it has the potential to play a far more proactive role during a building's life, and provide sources of renewable energy.
"Naturally," he says, "since one partner is Tata Steel, the solution will involve this material, but this focus is far from exclusive. We are looking at a variety of ways in which the envelope can capture, store and release energy."
Transpired solar collectors
Tata bought Corus Steel in 2010. One of the products Corus had developed and which the SBEC is researching is a transpired solar collector (TSC). This involves an equator-facing wall clad with steel that is coated with special solar absorbing paint. The cladding, mounted a few inches from the wall, is perforated with thousands of tiny holes.
The sun heats up the metal, and fans at the top of the gap draw up the heated air into a Heating, Ventilation and Air Conditioning (HVAC) system with heat recovery. Ducting transmits the heated air around the building.
"The building has four environmental chambers," Pillai explains, "with which we can experiment with different combinations using the TSCs. One is a workshop, where the system includes fan driven air heaters, and we expect the TSCs to contribute about half of the heating requirement, supplementing gas blowers.
"The upper floors and ceilings are made of concrete mixed with a powder called Micronal. Made by BASF, these are tiny capsules containing wax, a phase change material, which melts at 23o, absorbing surplus heat from the room," Pillai continues. "At night when the room cools, the wax solidifies and releases the heat, stabilising the internal temperature."
A new take on air source heat pumps
"The other three chambers are office areas, with variations on a theme," he adds. "Air source heat pumps will boost the pre-heated air from the TSCs and send it to underfloor heating. They can also work backwards in the summer to cool the building."
Air source heat pumps have come under some criticism lately for not being sufficiently efficient to warrant use. But the SBEC hopes that using solar pre-heated air will improve their performance, and will be checking this.
Later in the project they will be investigating other means of cooling buildings, perhaps using solar thermal heat engines to drive adsorption chillers.
Pillai says that the building will undergo blower tests in a couple of weeks to test their airtightness, which he hopes will be under 3m2/hr, but they are not aiming for the Passivhaus standard, which is one third of that level.
The insulation around the building includes polystyrene and mineral wool, the former of which has high embodied energy. I asked him whether the project will examine the embodied carbon in the materials and products used. Pillai responded positively.
"Absolutely. This is one of the unknowns in the field at the moment, and can be quite controversial. So we hope to work with as many people as possible to get reliable figures on how much energy is used to make the products, so we can choose the most efficient."
Steel is usually associated with high embodied energy, but Pillai counters that because much steel is recycled this need not be so.
Pillai said the collaborative approach extends to all the SBEC's work and invites potential partners. "We want to work with industry and customers to find the best solutions that are easy to install," he said.
SBEC has been designed by the Design Research Unit of the Welsh School of Architecture (WSA).
The Low Carbon Research Institute, housed in the building, is a team of 18 people drawn from Tata Steel, LCRI, Welsh School of Architecture and other industry specialists, partly funded by the Higher Education Funding Council For Wales (HEFCW) and £34m from the Welsh European Funding Office (WEFO).
Their work includes developing pre-finished steel products that deliver efficient energy functionality, and turning them into roof and wall components that will work on all building types. They're also R&D-ing PV, marine, hydrogen and other low carbon technologies.
An additional and connected centre, the PV Accelerator Centre is developing a photovoltaic pre-finished steel product and its manufacturing process. It is using the next generation of dye-sensitised PV technology, which works on a principle similar to photosynthesis in plants.
This product performs well in all light conditions and will hopefully make solar electricity much cheaper and easier to use. This £11m project has operated jointly with Australian company Dyesol, funded by £5m from the Welsh Assembly Government.