A new device collects two types of energy during daytime: To make it cool on one end and hot on the other to produce electricity round the clock. If the device is further improved, it could be used in off-grid Internet-of-things sensors.
The details of the findings are presented in the journal Science and Technology of Advanced Materials.
In fact, for 200 years scientists have known that electricity can be produced from a temperature gradient called thermoelectric generation. Recently, technologies for thermoelectric conversion are developed by changing material specifications and introducing new principles.
For instance, researchers have discovered that magnetic substances can produce thermoelectric voltage by creating a stream of electron spins along a temperature difference through a phenomenon called Seebeck effect. This increase in the length of the device perpendicular to the gradient boosts voltage.
To develop this further, scientists would like to fabricate more efficient, thin thermoelectric devices based on spin Seebeck effect. However, the slimmer the device, the more difficult it is to maintain a temperature difference between the two ends.
An initiative of two researchers and their colleagues at National Institute for Materials Science, Japan have solved the problem by creating a magnetic hybrid system that cools continuously at the top and absorbs heat from the sun at the bottom. This characterizes the device to collect two types of energy: The top of the device displays radiative cooling with heat loss in the form of infrared radiation, and solar radiation absorbed at the bottom.
Meanwhile, it is really important to take full advantage of renewable energy for sustainable solution for communities. Daytime radiative solar heating and cooling have both been used to improve a variety of thermoelectric applications.