Adsorption in the hot seat

2 min read

Vehicle air conditioning uses five per cent of fuel annually
Vehicle air conditioning uses five per cent of fuel annually

Technology that could reduce home heating bills by almost a third and cut car emissions by five per cent has been developed by researchers at Warwick University.

Domestic space and water heating currently accounts for 25 per cent of energy consumption in the UK. Meanwhile, vehicle air conditioning uses about five per cent of the vehicle fuel consumed annually and is responsible for more than two million tonnes of CO2 emissions in the UK each year.

Adsorption technology is a very efficient way of heating or cooling and uses heat from a gas flame or engine waste heat to power a closed system containing only active carbon and refrigerant.

During adsorption, molecules of the refrigerant accumulate on a solid adsorbent material such as carbon, creating a film. When the carbon is at room temperature, it adsorbs the refrigerant and when heated the refrigerant is driven out. A process that alternately heats and cools the carbon can be used to extract heat from the outside air and put it into radiators or hot-water tanks or extract the heat from the inside of the car.

At present, however, a suitable system would have to be roughly 300 litres in volume for a car air conditioner, while an even larger unit would be needed to create a home heat pump.

Now, the Warwick team has developed a design to make the units much smaller and lighter and has filed a patent on a design that distributes thin, typically 0.7mm-thick, sheets of metal throughout the active carbon in the heat exchanger. Each of these sheets contains more than 100 tiny water channels, making the heat transfer much more efficient. The equipment is up to 20 times smaller than was previously possible.

A new spin-out company, Sorption Energy, has been formed to focus on greener heating and hot-water systems for houses and air conditioning for cars.

It anticipates that in new vehicle models the system can be integrated with little or no extra cost, while retrofitting homes with adsorption systems would also be relatively straightforward. The systems should cost around the same as existing heating and cooling units.

Warwick has now entered a technical partnership with a global vehicle manufacturer to develop and demonstrate the technology and there has been considerable interest from the domestic heating and hot-water market.

Now, the Warwick team has developed a design to make the units much smaller and lighter and has filed a patent on a design that distributes thin, typically 0.7mm-thick, sheets of metal throughout the active carbon in the heat exchanger. Each of these sheets contains more than 100 tiny water channels, making the heat transfer much more efficient. The equipment is up to 20 times smaller than was previously possible.

A new spin-out company, Sorption Energy, has been formed to focus on greener heating and hot-water systems for houses and air conditioning for cars.

It anticipates that in new vehicle models the system can be integrated with little or no extra cost, while retrofitting homes with adsorption systems would also be relatively straightforward. The systems should cost around the same as existing heating and cooling units.

Warwick has now entered a technical partnership with a global vehicle manufacturer to develop and demonstrate the technology and there has been considerable interest from the domestic heating and hot-water market.