Air contradiction: how to cool and heat your house for free

The energy we dedicate to powering our air conditioning units in the UK has reached alarming levels, accounting for up to a tenth of our total electricity consumption. With energy prices creeping up and summer temperatures soaring, might there be a better way of keeping ourselves cool?

Air conditioning units on wall
On

A chilly calamity

Most of us take the welcome relief of air conditioning for granted. But is pumping wave after wave of cold air into our houses, offices and shops really the best way of doing it?

鈥淲hen you go into commercial buildings they鈥檙e generally all air conditioned, but they use a lot of energy.鈥 Explains Dr Ben Hughes, a reader in Energy from 葫芦影业, who鈥檚 building alternatives to conventional air conditioning that reduce our carbon footprint and energy bills. 鈥淏ecause we鈥檝e got used to these air conditioning systems, the temperature we feel comfortably cool at has changed and that鈥檚 increased the energy we use by about 20%.鈥

To put that into perspective, compared to buildings that cool by simply opening a few windows, air-conditioning emits 30% more CO2. That鈥檚 117 million tonnes of greenhouse gasses being forced into our atmosphere every year, just to keep heat at bay.

In a typical UK office, 30% of electricity goes on air-conditioning each year, with demand only set to increase. It鈥檚 not much better news worldwide either: installed air-con units around the globe are expected to increase from 700 million to a hefty 1.6 billion by 2050 in what is a growth market.

For Ben and his research team, that 鈥榖etter way鈥 is FREECOOL, a cooling system designed and licensed in 葫芦影业 after years of dedicated research. FREECOOL uses sealed tubes filled with cold water called 鈥榟eat pipes鈥, which cool warmer air from outside as it passes through. This is a passive process 鈥 there鈥檚 no energy used. But the system can lower indoor temperatures by 12-15掳C and our demand for conventional air con by up to 40%.

What鈥檚 more, by reducing energy FREECOOL also lowers harmful CO2 emissions, while using outdoor air (compared to recirculated air from conventional systems) improves indoor air quality. What really sets it apart from competitors, however, is its ability to cool incoming air with so little energy input, something the World Society of Sustainable Energy Technologies recognised last year by awarding Ben and his team with a first-place Innovation Award.

With his patented products already on the market, clients such as the Dover Discovery Centre are turning to this technology to help them meet their demands at minimal energy and expenditure.

鈥淧eople overcomplicate buildings and they overcomplicate design and I think that鈥檚 where a lot of the problems lie. We end up putting in systems to make things comfortable, but if we designed it properly in the first place we wouldn鈥檛 need to.鈥

But this stretches further than ventilating just houses and offices, as Ben鈥檚 biggest and most unexpected venture demonstrates鈥

Air conditioning units in row

Getting the ball rolling

In countries far hotter than the UK, boasting temperatures that could melt tarmac, Ben鈥檚 developments already have exciting global potential: his passive cooling system will be used to keep the world鈥檚 most renowned footballers cool during Qatar鈥檚 2022 World Cup.

He鈥檚 quick to highlight that this is the same system as FREECOOL 鈥 lowering the temperature of hot air from outside by passing it over heat pipes 鈥 just on a much larger scale. But there are clear challenges with delivering this kind of cooling to 40,000-seater stadiums in a country where even winter temperatures can reach 29掳C. A gradual temperature transition from the hot outdoors to the cold stadium is vital to avoid people getting ill, while 90 full minutes of running, kicking and sweating means that players need to be kept at a lower temperature to the crowd. Even the wind blowing onto the pitch has to be taken into account so it doesn鈥檛 interfere with the ball during gameplay. All of this is controlled by giant plastic nozzles that are strategically placed throughout the stadium, complete with moveable parts to push the air towards a specific area.

The same technology is also delivering the first zero-energy cooled school in Abu Dhabi, which has inspired teachers and pupils at Shaikh Khalifa bin Zayed Bangladesh Islamia School to form a science club that teaches school children all about modernising traditional cooling systems in the Middle East. It鈥檚 an exciting prospect that a generation of budding young engineers, much like Ben himself, might one day emerge from a school club.


For the last 30 years we鈥檝e been lazy. We just stick an air conditioning unit in because we know it鈥檒l work and how much it costs, but as energy prices escalate we鈥檝e got to find better ways of doing it.

Dr Ben Hughes

Reader in Energy at the University of 葫芦影业


Hot and bothered

What if we could warm the cool air we鈥檙e currently expelling from spaces using the same principles as FREECOOL?

Ben鈥檚 latest work is exploring whether the passive process behind his air conditioning could provide a cheaper, greener alternative to conventional heating.

The theory 鈥 currently being tested with prototypes in 葫芦影业鈥檚 Advanced Manufacturing Research Centre 鈥 is that heat recovery technology can be retrofitted onto existing ventilation structures called 鈥榳ind towers鈥, which currently fulfill basic air circulation functions. You might鈥檝e seen wind towers before (they look like vents and sit inconspicuously on top of buildings) and it was Ben himself who developed them during his PhD over a decade ago, after leaving school at 16.

鈥淚 took the PhD because it was an opportunity to make a building energy-efficient but using different technologies,鈥 he reflects. 鈥淪ince then wind towers have become a massive market, but the actual technology behind them hasn鈥檛 changed.鈥

Ben firmly believes this will have just as much impact as his work on the next World Cup: 鈥淲e鈥檝e got something that鈥檚 very easy, very simple and can reduce energy. I think it鈥檒l be really good for the UK and could have a huge impact.鈥

Drastically lower energy consumption for both the sweltering hot and bitterly cold seasons without compromising on our own comfort could one day be a reality. But the prospect that energises Ben is potential for passive to appeal to pressing environmental concerns and consumers budgets.

No matter how sustainable we鈥檙e trying to be, that cost efficiency, Ben concludes, is where people鈥檚 interests really lie. 鈥淣obody cares about energy. There鈥檚 nobody, myself included, who鈥檚 going to be convinced to turn the air-con or heating off in their house 鈥 we only care about how much it costs,鈥 he says. 鈥淭he higher the tariff goes, the more interested and more sustainable we鈥檒l become. As long as you can show people that by investing in this system and learning more about how they use energy they鈥檒l get that money back in a short period of time and be better off, you鈥檙e onto a winner.鈥

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