Have you noticed that if you don’t clean spilled water, it will evaporate sooner or later? This is because while water has a boiling point of 100oC, it can evaporate at different temperatures. Any form of evaporation results in cooling owing to the transfer of heat energy. In addition, the evaporation point of water changes based on its external pressure, with the lower the pressure, the lower the evaporation point. This serves as the basis of water under vacuum cooling.
How Evaporation Cools
Evaporation is an endothermic process, which means it uses heat from its surroundings to change from liquid to gas. Water molecules store the heat energy as latent heat, which lowers the temperature of the object.
Some common examples of evaporation causing cooling include:
- Sweating. When you sweat, the evaporation of the sweat cools your body.
- Plants. Plants lose water through their leaves, which cools them and the surrounding air.
- Earthen pots. The water in an earthen pot cools down because the water evaporates from the pot’s porous surface.
- Hot beverages. Hot beverages like tea and coffee cool down as the liquid evaporates.
The Effect of Pressure
The evaporation point of water changes if there is a change in its external pressure. Under normal circumstances, the pressure that water is subjected to is atmospheric pressure, which is 1,013 mbar. This is when its boiling point is 100oC. If you reduce this pressure in some way, the reduced pressure causes water to evaporate at a lower temperature. For example, at 8 mbar pressure, water evaporates at 4oC.
By evaporating water at a desired pressure, it is possible to generate cooling at required temperatures. Consider these examples that serve diverse needs.
- Air Conditioning. At 25 mbar, water evaporates at 21o At 12.5 mbar, it evaporates at 10oC.
- Refrigeration. At 8 mbar, water evaporates at 4oC. At 5.7 mbar, it evaporates at 0oC.
- Freezers. At 2 mbar, water evaporates at -15oC.
The Role of Vacuum
It is possible to reduce water pressure by using vacuum to lower the surrounding pressure around the water. This creates a pressure differential, where the outside pressure is significantly lower than the water’s internal pressure, causing the water to try and expand or even evaporate at a lower temperature due to the reduced pressure. Water evaporates at a much lower temperature because the reduced pressure allows water molecules to readily escape into a gaseous state.
How Our Patented Process Works
Our patented cooling and refrigeration technology relies on vacuum-driven water evaporation. The process gets underway by meticulously dispersing minute water droplets into an aluminum core. This core, placed in achamber, undergoes rapid vacuum-induced vaporization, effectively drawing heat away. The chilled core integrates into the unit’s water-based cooling loop, mirroring traditional refrigerant systems, to deliver temperature reduction to spaces like cold rooms and commercial refrigerators.
Why Use Water as a Refrigerant?
All refrigerants known to mankind until now come with varying global warming potential (GWP) values, with Puron and Freon on top of the chart. Some cause ozone depletion, with others not being particularly safe to use. After all, most fall under the “asphyxiant” bracket. Using water as a refrigerant for vacuum-driven cooling comes with numerous benefits.
- Non-asphyxiant
- Non-flammable
- Non-toxic
- Zero GWP
- Zero ozone depletion
- High heat capacity
Conclusion
Harnessing the potential that water presents as a refrigerant is all too possible by turning to water under vacuum cooling, and the benefits on offer are plain to see. What also helps is that this technology can serve diverse cooling requirements across industries. If you’re wondering how this new and path-breaking green technology can help address your cooling or refrigeration concerns, speaking with a CleanCold Technologies expert might be in your best interest.