As the world's temperature rises, the demand for refrigeration and air-conditioning equipment will continue to grow, and this will in itself exacerbate the crisis: the efficiency of modern refrigeration devices is not so high and they require much energy, leading to greater emissions and increased greenhouse effects, so passive cooling systems are welcome, and the new invention of MIT scientists promises to improve their efficiency.
A group of scientists from the Massachusetts Institute of Technology developed a forward-looking three-layer panel for passive cooling. It is stated that technology allows even in a wet climate to reduce the panel temperature by 9.3 °C compared to the ambient temperature. All that is needed for such a cooling panel is to add water to it. Very little water. For a hot and arid climate, it will have to be done more often every four days, and for regions with increased humidity it will be sufficient to share water once a month.
The device resembles the solar panel. Its upper layer is an aerogel, a porous vapour-proof plastic structure filled with normal air pores. Under the aerogel is a layer of hydrogel, also a layer of polymer, but already with water in pores. This layer is much like hydrogel medical patches to treat open wounds. The third layer is the lowest layer, the mirror surface reflecting the sun beams back, which prevents heating of the cooled object behind the panel.
The researchers pointed out that for the first time they combined in one decision long-known principles, namely, evaporative cooling and radiation cooling, where infrared radiation from an object goes into space rather than scatters into the surrounding space, a number of cooling systems have already been proposed, which may even allow solar panels to operate at night, and an interesting solution has also been the use of aerogel as thermal insulation, which has further protected the cooled object from solar radiation heating.
Aerogel transmits infrared radiation to the hydrogel layer, but cuts off all other sun rays. Infrared irradiation volatilizes the water in the hydrogel layer and vents through the aerogel. The excess infrared radiation and the panel's own infrared irradiation are emitted into space. The source material in such a scheme is conventional water. A prototype demonstrated the record effectiveness of the panel, providing a difference between the ambient temperature and the panel up to 9.3 °C.
The solution proposed could be for both houses and containers for the transport and storage of foodstuffs in regions where there is no stable source of electrical energy; such panels could be fitted with food pavilion lids; in a wet climate, this would increase the storage time of perishable products to 40% and three times dryer conditions.
The only barrier to commercialization remains aerobics, whose production is not yet effective; today, it is produced only in laboratory conditions during the mixing of polymer and solvent and very long subsequent drying; and scientists promise to develop technology for the simplified production of aerogel, and then passive refrigerators and passive air conditioner "busters" can become massive.