Award-Winning Hybrid Solar Producer Claims To Generate Most Solar Heat and Power Per Square Metre

Naked Energy has deployed its award-winning Virtu hybrid-solar technology on Swansea University’s SPECIFIC Innovation & Knowledge Centre’s Active Office

Virtu PVT (Photovoltaic Thermal) is providing 2.4kWp electrical energy as well as 9.6kWp thermal energy to the Active Office building. 40 Virtu tubes have been designed to integrate on the South facing facade, increasing solar gain in the shoulder and winter months.

“The United Kingdom’s first truly energy-positive office is allowing Britain to lead the world in terms of renewable technologies,” says co-founder and CEO of Naked Energy, Christophe Williams.

The life-size working demonstration of the ‘Active Buildings’ concept in which buildings are designed to generate, store and release energy using one integrated, optimised system – which launched last Summer

The Active Office was designed and conceived by SPECIFIC Innovation & Knowledge Centre and funded by Innovate UK, with support from Swansea University and the European Regional Development Fund through the Welsh Government. Other collaborators in the project include Akzo Nobel, NSG Pilkington, Cisco and Tata Steel.

The Active Office is geographically located next to The Active Classroom: the UK’s first energy positive classroom on the campus of Swansea University. The classroom project was named Project of the Year 2018 by the Royal Institution of Chartered Surveyors Wales (RICS). In its first year of operation, the classroom generated more than one and half times the energy it consumed.

Two Active Buildings share energy with each other and electric vehicles and can perform controlled export, effectively timeshifting the renewable generation, demonstrating how SPECIFIC’s ‘Active Buildings’ approach can be applied within energy-resilient solar-powered communities.

The Active Office only uses commercially available technologies and existing supply chains. It demonstrates that the ‘Active Building’ approach is applicable right now.

“The future is here today,” says Christophe Williams.

Naked Energy has proven its hybrid solar collectors for both heating water and generating electricity is the most efficient use of space on a building.

“With all commercial buildings, space is at an absolute premium. Maximising energy from every square inch available is now the order of the day”.

Professor Dave Worsley, SPECIFIC Innovation and Knowledge Centre says: “I think the work with Naked Energy has been really important to us because it’s given us an entirely new approach to generating both electricity and heat at the same time. I think something else that’s really important about the Naked Energy tube setup is they actually look really fantastic, so as an architectural feature on the building, they’re not only functional but people actually really like to see them.

Buildings in the ground-breaking Active Buildings scheme are harnessing a range of technologies to generate, store and release their own solar energy in one system.

It is believed that the United Kingdom’s construction sector is poised to adopt the approach to new builds.

“With Britain’s 2030 Paris Climate Change objectives, Naked Energy is helping lead the march towards energy-positive buildings,” says Christophe Williams.


Notes To Editor:

Virtu by Naked Energy for Active Offices

Naked Energy Co-Founders Christophe Williams and Nick Simmons

Naked Energy’s Virtu - The EIT Climate-KIC supported technology



Naked Energy set out to provide clean, cost-effective energy through its innovative designs and business models. They believe that profit and sustainability are not mutually exclusive. Energy security, cost and environmental impact drive everything Naked Energy does. Energy for heating and cooling accounts for approximately 50% of global energy demand and 39% of carbon dioxide emissions. Increasing urbanisation, growing populations and economic development present unique challenges to how thermal energy is consumed and delivered. Renewable thermal energy has received a lot less attention than renewable electricity but has an even more important role to play. That’s why Naked Energy developed Virtu. They looked at everything from the end consumer’s perspective. Starting with the premise that the consumer wants to take control of their energy in terms of security of supply, cost and environmental impact. Their initial focus is on commercial and industrial customers where they can make the biggest positive impact. After staff costs, energy is the next highest controllable expense. By definition, businesses are in a specific location and will take up a clearly defined space in the built environment. Naked Energy wants to help businesses optimise the amount of energy they can generate for a given space in the most economical way possible that will have the greatest positive impact on their energy costs and CO2 emissions without compromising on the availability of that energy when it is needed.

That means generating more energy from less space. Naked Energy is also very conscious of ensuring that the cost of delivering the solution is optimised so that the savings generated recoup the initial investment as quickly as possible.


VirtuPVT generates both heat and power from the same space. The sun provides up to 1000 Watts of energy for every square metre of space. If a technology were able to capture all 1000 Watts it would be 100% efficient, it would have an energy density of 100%. The best conventional photovoltaic solar panels can convert between 20% and 25% of the sun’s energy into electricity. The best solar thermal collectors can capture up to 80% of the sun’s energy making their energy density much higher depending on the temperature of the heat being collected (typically heating water which can then be used simply as hot water or converted into space heating or space cooling). VirtuPVT collects the same amount of electricity as a PV panel (we use the same high-efficiency PV cells as the best PV modules) and the balance of the energy a solar thermal collector would get as well. Therefore 20% of the sun’s energy is converted to electricity with up to 60% also being collected as heat. This means that on a typical commercial flat roof far more energy is captured for the limited space available. Moreover, because VirtuPVT uses the same materials for both heat and power collection it means that the cost of those materials is recovered more quickly from the dual energy cost savings. Even more importantly, given that economies of scale have brought down the cost of equipment, the remaining costs of design, delivery, installation and maintenance that are all linked to labour costs are also recovered more efficiently.