Keeping cool essential to future sustainable cities

With populations rising, how do we plan, design and manage cities that can cope with increasing pressure on resources while meeting carbon and climate challenge needs?

Will our investments in cities and infrastructure today be resilient, and how do we re-engineer cities to reduce the carbon footprint by 80 per cent while retaining societal wellbeing?

Insulation and heating of homes and public buildings is a significant burden for local councils in the UK, but cooling may be the real challenge in the next few decades.

As the climate continues to change and heat up, keeping cool will become more important. Homes and recent infrastructure built in recent times are designed to keep us insulated and warm, but we need to start rethinking these designs.

The demand for cold energy is significant but largely underestimated. Cooling currently consumes up to 14 per cent of Britain’s electricity, and £5.2 billion each year is spent on energy for cold across the grid and transport. These figures are increasing and will, of course, be significantly higher in warmer countries.

If we can begin to think about heating and cooling on a systems level rather than on an individual building basis, important economies and efficiencies can be made.

Combined heat and power systems that use gas-fired turbines can incorporate ‘heat exchangers’, which could mean provision of both hot and cold to keep us warm in the winter and cool in the summer. Furthermore, if this is built into a district heating system that connects a number of buildings, efficiencies could be made to meet differing demands.

Community-based and decentralised schemes could be the way forward for meeting some of these energy reduction targets. If you were to consider connecting households in one area with a swimming pool, for example, you’d see that the demand for energy could be complementary, meaning less wastage and shared bills. A typical household in a development will, for example, use more energy in the morning and evening, whereas a swimming pool would use more during the working day.

This concept has been trialled on a small scale in the UK and in some major projects such as the London 2012 Olympic Park. The 6.3 MW system at the Olympic Park provided heating to all permanent venues and cooling to the Handball Arena and Press and Media Centre through one single energy centre at Kings Yard and was an exceptional example of modern engineering providing sustainable and efficient systems.

District heating systems such as these provide huge economic and environmental benefits, including reducing carbon emissions . Combining heating and cooling production can also relieve the need for chemicals such as ammonia that are often required for cold provision, thereby dramatically improving health and safety.

In order to tackle the needs of future generations of communities, we need to develop sustainable solutions to the rising demand for cold and cooling. The latest University of Birmingham Policy Commission on cold and cooling is considering how to bring together a range of technologies and innovations to develop a system-wide approach that will deliver against carbon reduction targets as well as stimulating an important UK hub of technology manufacture and development.

Peter Braithwaite, Director of Engineering Sustainability, Birmingham Centre for Resilience Research and Education, University of Birmingham