Create material under the sun

2014/11/27 Etxebeste Aduriz, Egoitz - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Materialak
• Energia
• Ingeniaritza

Stanford University engineers have created a new material that, in addition to expelling heat, practically reflects solar radiation. The material does not need energy and can be effective for cooling buildings. The prototype presented in Natura is able to cool to a temperature lower than 5 ° C in the area.

A new material has been designed for heat emission at a certain infrared radiation frequency. In fact, in this frequency it crosses the atmosphere without heating the surrounding air and the heat exits directly into space. This is due to the structure of the material. It consists of seven layers of silica dioxide of different thickness and hafnium oxide on a thin layer of silver. And in total only 1.8 µm.

But heat removal is not all. So far this type of passive radiators were only efficient at night, since during the day they were not able to resist the heat of the sun. However, this new material, besides being a radiator, is a very efficient mirror at the same time. It reflects 97% of solar radiation. Thus, they have shown that, despite being in the sun, it cools well.

However, there are still challenges to overcome for buildings to serve as refrigeration, such as how to transfer heat from the building to radiators on the roof. Another challenge could be the production of material on a large scale, although researchers do not see big problems for it.