Graphene drives potential for Next-gen Green Fuel-Efficient Cars
>>converting heat into electricity. Graphene’s range of superlative properties and small size causes the transfer of heat through the material to slow leading to the desired lower operating temperatures. Harvesting heat produced by a car’s engine which would otherwise be wasted and using it to recharge the car’s batteries or powering the air-conditioning system could be a significant feature in the next generation of hybrid cars.
The average car currently loses around 70% of energy generated through fuel consumption to heat. Utilising that lost energy requires a thermoelectric material which can generate an electrical current from the application of heat. The challenge with these devices is to use a material that is a good conductor of electricity but also dissipates heat well.
Currently, materials which exhibit these properties are often toxic and operate at very high temperatures – higher than that produced by car engines. By adding graphene, a new generation of composite materials could reduce carbon emissions globally from car use. The team, led by Prof Ian Kinloch, Prof Robert Freer and Yue Lin, added a small amount of graphene to strontium titanium oxide. The resulting composite was able to convert heat which would otherwise be lost as waste into an electric current over a broad temperature range, going down to room temperature.
Prof Freer said: “Current oxide thermoelectric materials are limited by their operating temperatures which can be around 700 degrees Celsius.” …”The new material will convert 3-5% of the heat into electricity. That is not much but, given that the average vehicle loses roughly 70% of the energy supplied to it by its fuel to waste heat and friction, recovering even a small percentage of this with thermoelectric technology would be worthwhile.”
Improving fuel efficiency, whilst retaining performance, has long been a driving force for car manufacturers. Graphene could also aid fuel economy and safety when used as a composite material in the chassis or bodywork to reduce weight compared to traditional materials used. http://www.manchester.ac.uk/discover/news/article/?id=14934
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