Higher Power

Thermoelectric devices have been used for almost a century, however their efficiencies are very poor. For example the solid state fridges that have appeared on the market in recent years (which are the opposite of a thermoelectric generator and use electricity to cool contents, or if the polarity is reversed to warm contents) have an efficiency about 25% that of regular fridges.

 

It is only relatively recently that the reasons behind this lack of efficiency have been understood. Certain nanomaterials have been developed which have efficiencies 3 or 4 times greater than the previous best semiconductors. The reason is in the nanoscale structure of these materials which helps slow down heat transfer , while still allowing electrons to move freely. By combining several of these thermocouple of nanostructured materials together, thermopiles capable of generating reasonable quantities of electricity can be generated.

In the future it is envisaged that such thermopiles could convert waste heat from vehicle engines and exhausts to electricity, removing the need for alternators to power electrical components and recharge the battery. They also have applications in running sensors and small devices such as watches from a person’s body heat.