Breath of fresh air from spin-out
A University of Cambridge spin-out is trialling a new hi-tech ventilation system it claims has the potential to make massive energy savings across new and refurbished buildings in the UK.
Buildings currently consume about 40 per cent of all the energy used in this country and E-Stack believes its “eco-friendly” ventilation system is capable of reducing this amount by up to 50 per cent, offering a green solution to ventilation throughout the year.
The start-up, based at St John’s Innovation Centre, first piloted a version of its stack at Harton and Newton Primary School in Cambridgeshire and has since installed two further prototypes at schools in Birmingham and Northampton.
It is using the pilots to gather and evaluate data to prove the practical applications behind its hypothesis to a list of contractors and architects who have declared an interest in the technology.
The huge amount of energy consumed by buildings in the UK comes in the form of heating, lighting, air-conditioning and ancillary equipment like computers.
Through use of modern building materials with high specification insulation, a naturally ventilated building can provide a comfortable interior environment while using 30-50 per cent less energy than a conventional air-conditioned building.
The new ‘E-stack’ system has the potential to reduce the energy consumption used for heating and ventilation in such naturally ventilated buildings by a further 50 per cent.
It uses a hi-tech automated chimney that accesses the top of the room, in combination with vents at low level. In summer, the system ensures that the room remains well-ventilated by bringing in fresh air from below and allowing hot air to escape upwards.
The company was established by Professor Andy Woods and Shaun Fitzgerald following years of research at the University of Cambridge BP Institute. Their investigations, allied to discussions with architects, led them to ponder how to ventilate rooms with fresh air in the winter months without “freezing” the inhabitants.
Within weeks they had the foundations of the E-Stack system, which would not only provide the fresh air in winter and summer, but redistribute the hot air expelled by lights, computers and even people.
Fitzgerald said: “With today’s insulation processes, the amount of heat gains in modern buildings is enormous. Rather than use fossil fuels, we want to harness and exploit these gains.
“Sat down at your desk you generate 100 watts and need 10 litres of fresh air. With 100 watts it is possible to heat 10 litres of air by 10ºC. If the temperature outside is 10ºC, the 100 watts can lift it to 20ºC, giving you a habitable air temperature and that’s before you’ve considered all the computers and lights etc.”
E-Stack will use its industry contacts to help refine the patent-pending technology into products that will have a “maximum impact” in the marketplace.
“Ventilation systems fall into two categories, mechanical and natural,” says Fitzgerald. “Mechanical systems use fans and consume twice as much energy as natural systems. However, the achilles heel of the natural system is how to distribute air more evenly.”
The E-Stack system keeps the air warm in the winter months while carefully monitoring carbon dioxide levels in each room. When they reach specified level, the system responds and opens vents enough to provide adequate fresh air.
E-Stack’s strategy for the first two years is to concentrate on proof of concept and make sure the technology is proven in real buildings, ideally schools and offices. Further products will follow with input from major industry players, including systems developed for residential properties.
The company’s University research work was part of a Cambridge-MIT project funded by BP. When E-Stack needed to prove its idea worked and went in search of a life-size model, it secured money from the University to set up a demo at Newton Primary.
Until then funding had been provided by BP, which is now sharing the costs of the two Midlands projects together with E-Stack’s client.
Miranda Weston-Smith from Cambridge Enterprise, who negotiated the legal agreements between CMI and BP, said: “This spin-out got going in record time thanks to BP’s funding commitment.”