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Buildings as power stations. A case study: The Active ClassroomAugust 2018

Written by Joanna Clarke, Building Integration Manager at Specific: An innovative case study of a newly constructed building that generates more energy than it consumes.

At Specific Innovation and Knowledge Centre (, an academic and industrial collaboration led by Swansea University, a new concept for buildings of the future is under development – buildings that generate, store and release their own energy.

The vision is to turn buildings into power stations, using solar energy to generate both heat and electricity on the building envelopes, and to store this energy in batteries and thermal stores for use within the building as heat, power and lighting.

In 2016, an “Active Classroom” demonstrator building was constructed on Swansea University’s Bay Campus and showcased during the week of the British Science Festival in September 2016. The building demonstrates a new off-site construction technique, together with some of the latest novel renewable energy technologies being developed at SPECIFIC and by collaborative companies. Since its completion the building has been used for teaching and many other events, enabling the collection of valuable data on its performance in use. The building is fully monitored, with a bespoke building management system designed to capture accurate data on both energy generation and consumption.

New photovoltaic roof

17kWp Building Integrated Photovoltaic Roof Active Classroom from the northeast

The roof covering to the south consists of a new building integrated photovoltaic roof, manufactured by a Welsh company called BIPVCo, who bond photovoltaic modules onto Tata Colorcoat® Urban coated steel roof panels. This generates approximately 17kWp of electricity, which is stored in two 30kWh aqueous hybrid ion batteries, providing a total of 60kWh of storage – enough to supply the building for approximately two days, without top-up.

On the south elevation, there are two solar air collectors (Tata Colorcoat Renew SC®), which provide a renewable pre-heat for an air source heat pump and a mechanical ventilation and heat recovery (MVHR) unit, delivering space heating and hot water for the building.

New heating system

Novel Resistive Heating System

A novel resistive heating system developed at SPECIFIC supplies the majority of space heating within the building. This consists of a conductive coating applied to pre-painted steel sheets and bonded to the floor panels. The floor temperature is controlled remotely and set to maintain an internal room temperature in the main teaching space of 18°C during week days, when the space is occupied.

These combined heating systems enable the building to operate at comfortable temperatures all year without the need for any gas connection.

The electrical and heating systems are fully monitored, and the data is currently being analysed to determine actual performance of the building in use. For various reasons, a permanent connection to the main electricity grid is yet to be obtained, which has to date prevented total electricity generation from being measured accurately. However, based on current electricity generation figures and predictions using local weather data, we are confident that the building is energy positive, generating more energy than it consumes over an annual period.

Storage of renewable heat

At SPECIFIC, researchers are also developing a thermo-chemical heat store, capable of storing renewable heat generated during the summer months for use in the colder winter months. It is planned to install a prototype of this store in the Active Classroom later this year, further reducing the amount of energy imported into the building.

Extra funding

For SPECIFIC and its funders – the European Regional Development Fund through the Welsh Government, the Engineering and Physical Sciences Research Council (EPSRC) and Innovate UK – the success of this building has been critical for new developments. In November 2017 Innovate UK granted SPECIFIC £800K funding to deliver a second demonstrator building, known as the Active Office, which is currently under construction adjacent to the Active Classroom. This will include a curved building integrated photovoltaic roof capable of generating 23kWp of electricity, which will be stored in 100kWh of battery storage.

A novel solar thermal system, consisting of photovoltaic panels in evacuated tubes to provide electricity, space heating and water heating, will be installed on the south elevation and monitored to determine its performance.


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