How do you prevent nighttime cold from damaging crops? Researchers at a Chinese university have created a film that protects plants and fields through passive heating at night.
At night, the temperature near the ground can drop to the sub-freezing point, possibly damaging crop yields as well as power lines and farm equipment.
Maintaining an adequate temperature at night is a long-standing issue for the agricultural sector. Conventional methods, which can be ascribed to the macro-category of active heating, require a large amount of energy and have a strong environmental impact.
Nanophotonics promotes passive heating
Inspired by these considerations, a group of Chinese scientists has developed a radiative heating system that works passively. How? Through a nanophotonic film that can absorb different wavelengths of infrared light to conserve heat.
The journal “Light-Science & Applications” published the research, titled Night-time radiative warming using the atmosphere, where the special feature of this passive insulating film is described.
The film consists of five ultrathin layers of alternating germanium and zinc sulfide and has negligible volume consumption compared to conventional insulating blankets.
The nanophotonics-based heating strategy also allows the film to passively inhibit thermal radiation while actively utilizing that of the atmosphere.
The use of a photonic engineering film, due to its high reflectivity in the atmospheric transparent band and high absorption capacity in the atmospheric radiative band, allows for a temperature increase of 2.1/4.4°C compared with typical low-emissivity films.
Such a strategy for night heating opens up new perspectives for sustainable energy system efficiency and progressive containment of consumption. Two inescapable goals to face the challenges of climate change with awareness and optimism.
Source: nature.com, rinnovabili.it