The UK’s first energy-positive office has opened at Swansea University in Wales.

Dubbed the Active Office, and opened by Wales’ Secretary of State Alun Cairns on 21 June, it combines several new technologies to let it generate, store and release solar energy in one integrated system.

A curved roof with integrated solar cells demonstrates the flexible nature of the laminated photovoltaic panel deployed, and a combined photovoltaic thermal system on the south-facing wall can generate both heat and electricity from the sun.

Energy storage is supplied by a 100kWh lithium-ion battery system, and a 2000-litre water tank for the heat.

It has three electric vehicle charging points and the building’s estimated spare annual generation of 8.5MWh would be enough to drive 1.4 times around the world in a Nissan Leaf.

The Active Office is sited next to the Active Classroom, the UK’s first energy-positive classroom, which, in its first year of operation, generated more than one-and-a-half times the energy it consumed and recently was recognised as Project of the Year by RICS Wales, and has won seven awards in total.

The classroom features a building integrated photovoltaic roof, aqueous hybrid ion battery storage, a novel resistive heating system, and new coatings for steel cladding developed by Tata Steel.

Modular construction

The Active Office is designed to be easy to reproduce, taking only one week to assemble using off-site construction. All the technologies are commercially available now, meaning they can’t be used on any new building.

The two buildings will be able to share energy with each other and power electric vehicles, to show how the concept may be applied in an energy-resilient solar-powered community.

Both buildings were designed by SPECIFIC, a UK innovation and knowledge centre led by Swansea University. Kevin Bygate, its chief operating officer, said: “Offices are enormous consumers of energy, so turning them energy-positive has the potential to slash fuel bills and dramatically reduce their carbon emissions. Turning our buildings into power stations is a concept that works, as the Active Classroom shows. This new building will enable us to get data and evidence on how it can be applied to an office, helping us refine the design further.

“The Active Office is a first, but it isn’t a one-off. It is quick to build using existing supply chains, and uses only materials that are already available. This is tomorrow’s office, but it can be built today.”

Ian Campbell, executive chair of Innovate UK, said: “It’s difficult to overstate the potential of developing a building that powers itself. The concept could genuinely revolutionise not only the construction sector but completely change how we create and use energy, so the opening of the Active Office in Swansea is an exciting step forward.”

SPECIFIC is also working with Pobl Group and Neath Port Talbot Council to develop 16 innovative homes that integrate renewable technology and energy efficient materials to tackle carbon emissions and fuel poverty – and be the first development of social housing to use these technologies in the UK.

The technology

The BIPVco photovoltaic roof uses thin film solar cells (Copper Indium Gallium Selenide) that are bonded directly onto pre-painted steel to create a curved roofing system that can be installed in the same way as a conventional roof.

These panels are less bulky, more flexible and lightweight than traditional crystalline based panels and require very little maintenance. They also perform better in low light conditions. The roof contains 93 PV modules estimated to provide an energy output of 22kWp.

The windows are special too. Although double-glazed, they offer the same level of performance as traditional triple glazing by using high-performance glass filled with argon gas.

The building also hosts a living wall, planted with the help of local school children, containing 450 plants and 10 different native species. Besides fostering biodiversity it helps to regulate temperature and reduce carbon footprint, protect the building façade and improve air quality.

Photovoltaic thermal tubes draw thermal energy away from solar cells for space heating while also generating electricity. The benefits of these “hybrid” panels are that they reduce installation time and cost while maximising useable installation area, and the vacuum tube thermal collectors draw heat away from the PV cells, making them more efficient.

If required, an air source heat pump acts as a top-up or back-up to the solar thermal generation to charge the thermal store, which includes a 100-litre accumulator tank besides the 2000 litre storage. The system provides all space and water heating for the office via an intelligent building control system. This is a Cisco Network Architecture system that includes 18 wireless access points for smart building sensors and is capable of DC as well as AC power distribution for services such as integrated, smart, low-voltage lighting.

The building itself is constructed of twelve modules that were delivered to site and craned into position in just three days.

For the wall cladding, Tata Steel’s Coretinium panels, manufactured from thin gauge pre-finished steel, combine rigidity with relatively low weight, and are coated with a durable paint. At their end-of-life, they can be treated as general steel scrap and be completely recycled without the need to separate the core from the skins.

On the health and safety front, the interior wall paint by Dulux is an anti-formaldehyde formulation with an active bamboo ingredient allowing it to capture and purify harmful internal air pollutants such as formaldehyde and benzene to keep indoor air fresh. It also contains tea tree oil extracts that can kill germs and bacteria, making it low VOC, mould resistant and anti-bacterial.

David Thorpe’s two new books are Passive Solar Architecture Pocket Reference and Solar Energy Pocket Reference. He’s also the author of Energy Management in Building and Sustainable Home Refurbishment.

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