Scientists at Saudi Arabia’s King Abdullah University of Science and Technology have developed a cooling system that does not require electricity, using saltwater and solar cooling.
The system is currently in the experimental phase and has been successfully tested on a small scale.
According to the details, a natural phenomenon called “phase change” has been used in the preparation of this system.
Under this phenomenon, solid salt crystals absorb energy while dissolving in water. That is, adding salt pens to hot water will cool it faster.
After using a variety of salts, experts found that a salt called “ammonium nitrate” had the highest cooling effect.
It dissolves very quickly in water, so its cooling capacity is four times that of ammonium chloride, which proved to be the second-best salt in this comparison.
During the initial experiments, when ammonium nitrate and water were placed in a metal cup, only 20 minutes later, the water temperature dropped from 25 C to 3.6 C.
Even after that, the temperature of this metal cup remained below 15 degrees Celsius for about 15 hours.
Experts say that ammonium nitrate is widely used in making synthetic fertilizers while it is also very low cost. Therefore, it will be very easy to use in any cooling system.
Now experts are trying to improve the system so that water can be steamed from the heat of the sun and the remaining ammonium nitrate can be reused.
In order to save water in arid and desert areas, additional solar stills can be installed along with the system which collects steam, converts it into water and sends it back into the system.
This is technically possible, but it will require experts to try dozens, if not hundreds, of designs to create an effective system that is not only widely used but also low-cost.
Note: Details of this invention have been published online in the latest issue of “Energy and Environmental Science.