During laboratory tests, scientists managed to lower the temperature of a mixture of ammonium nitrate and water from 25 degrees to 3.6 degrees Celsius in just 20 minutes without using electricity. This result forms the basis of a new cooling technology.
It is noted that scientists from King Abdullah University of Science and Technology in Saudi Arabia have developed a new technology that allows cooling the air without using electricity. The system is called NESCOD ("Cooling Without Electricity and On Demand").
The cooling mechanism is based on a chemical process called endothermic dissolution. When some salts dissolve in water, instead of releasing heat, they absorb energy from the environment. As a result, the temperature drops rapidly and significantly.
The scientists tested a number of salts to determine the best result. The highest indicator was recorded for ammonium nitrate.
Researchers stated that ammonium nitrate can dissolve up to 208 grams in 100 grams of water, whereas this indicator is usually below 100 grams for other salts.
According to the scientists, the higher the dissolution, the more salt dissolves and the more heat is absorbed during the process. This substance also has additional advantages: it is cheap, widely available, and already produced on a large scale.
To demonstrate the potential of the technology, scientists dissolved the salt in water inside a metal container and placed it into a Styrofoam insulated box. Consequently, the temperature of the container dropped to approximately 3.6 degrees Celsius and remained below 15 degrees for more than 15 hours.
Scientists have also developed a way to reuse the technology. The NESCOD system envisions a regeneration cycle that restores the salt after each use and does not require an external energy source.
After the salt solution returns to room temperature, the researchers restore the process using solar energy through a special 3D regeneration device. The device is made from a material designed to absorb the maximum part of the solar spectrum.
As water evaporates, ammonium nitrate crystals form on the outer surface of the container. According to the scientists, these crystals detach and fall off by themselves under the influence of gravity, which almost automates the collection process.
The scientists also mention that the evaporated water is not lost. During solar distillation, the vapor can be collected, condensed, and reused, which is especially important for hot and dry climates.Demokrat.az