Researchers at the University of Lisbon's Centro de Química Estrutural have discovered that the addition of graphene to the working fluid of solar collectors helps to regain some of its lost efficiency. Solar thermal collectors are seen as a simple and inexpensive way to make use of solar energy. Pure water is an efficient heat-transfer fluid, but it must be mixed with antifreeze to prevent damage to pipes during freezing conditions, and this lowers its performance.
The properties of an ideal heat-transfer fluid in a solar collector include a high thermal capacity and a freezing point outside of the temperature range likely to be encountered. Unfortunately, in the case of water, satisfying the latter requirement means compromising on the former, as mixing water with antifreeze makes it a less effective carrier of heat.