Solar thermal or solar thermal energy is usually based on the use of mirrors to heat bodies of water and thus take advantage of the heat from the Sun to produce energy, either thermal or electrical. But there are other ways to take advantage of the heat of our star thanks to nanoengineering.
Harvest the heat of the Sun. A team of researchers has formulated a new technology aimed at converting solar radiation into thermal energy. The proposed system promises two advantages: efficiency and scalability.
The creators of this mechanism emphasize that its efficiency is high because its high absorbency is not, 94% depending on the work; but also by minimizing thermal emissivity. This thermal energy can be used as such or it can be converted into electrical energy through thermoelectric materials.
“Solar energy is transferred as an electromagnetic wave within a wide range of frequencies,” explains Ying Li, one of the study’s authors, in a press release. “A good solar thermal energy harvester must be able to absorb the wave and heat up, thus converting solar energy into thermal energy. This process requires high absorbency (100% would be perfect), and (…) also suppressing its thermal radiation to preserve energy (…), which requires low thermal emissivity.”
From the tiny to the big facilities. Until now, solar thermal systems based on micro and nanostructures suffered from scalability problems: building them implied excessive costs. It’s one of the problems that Li and his team think they’ve solved with his design.
The key to this is in a nanoscale quasiperiodic pattern. In this pattern the molecules are arranged for the most part in a regular pattern, with occasional irregularities (hence the “quasi-“). These “defects”, however, do not cause problems in the operation of the mechanism or in its efficiency.
This nanostructure self-assembles thanks to iron oxide (Fe3O4) molecules introduced together with graphite (carbon). The oxide organizes the rest of the matter around it in a structure, which means that it does not have to be manufactured at the nanoscale, which in turn implies that it is easier to scale this system.
Details of the operation of the mechanism. Zifu Xu et al.
A versatile technology. The ease of converting thermal energy into electricity and the versatility that this entails are also factors that Li and his team boast about.
In this regard, the researchers built a thermoelectric version of their design based on nanoparticles. They thus managed to generate 20 millivolts per square centimeter. According to the team, enough to illuminate 20 LEDs per square meter of solar installation.
“This highly versatile structure and our basic research can be used to explore the upper limit of solar energy collection, such as scalable and flexible solar thermoelectric generators, which can serve as a component of solar collection assistance to increase the overall efficiency of photovoltaic architectures”, stated Li.
A boost to renewables. The coexistence of a climate crisis and the worst energy crisis for almost 50 years have highlighted the need to seek more efficient alternatives to generate energy for our daily lives. Solar energy will play an important role in the energy mix of the future, but its potential for improvement is still enormous. Work like this can help us to better “squeeze” the source of almost all the energy our planet has: the Sun.
Image | Pixabay
In Xataka | Solar panels are a black hole of water. Electrostatic repulsion wants to solve it
