Nowadays, in almost every type of building it is necessary to create a proper ventilation and air conditioning system. It is thanks to them, regardless of the weather conditions outside, that we can maintain the most optimal temperature and humidity in the rooms we are staying in. Currently, freon air conditioning is the most commonly used air conditioning in the world, but as it turns out, the installation of ice water may be a better alternative - explains energycool.pl employee.
Chilled water unit - working principle
In this particular type of refrigeration plant, it is the ice water that is the working medium. As far as its construction is concerned, it is the same as in heating systems. The difference, of course, is that it is fed with cold water. Ice water is produced in a chiller, or ice water generator. It then moves through the pipes from the source to the receivers.
The most common form of ice water is usually a solution of ethyl or propylene glycol with water or other brine. This is due to the rather uncomfortable clotting of ice water.
Chiller is a source of chilled water, it acts as a heat exchanger. This type of equipment is most often used in hotels, production halls, shopping malls or office buildings and provides a source of cooling for air conditioning.
A chiller installation is better than a freon air conditioning system because it has greater resistance to failures. This is due to its increased tightness.
The chiller works in conjunction with a cooler or fan coil. The first of these devices is placed in the air handling unit, while the second one in the room itself.
Chiller - scheme
An installation that uses chilled water consists not only of its unit, but also of fan coils, which are water-air heat exchangers. When air flows through the fan coil, the temperature of the ice water in it will rise by about 5-6 degrees Celsius. A pump that feeds water at pressure is also extremely important in such an installation, thanks to which ice water can be transported to the final consumer.
The most important part of the installation is, of course, the chiller, which makes it possible to drain heat from the water. The chilled water produced in this way is delivered to fan heat exchangers or similar terminal equipment and then returned to the unit when heated. It should also be noted that the heat exchangers are cooled by evaporators through liquid coolers and condensers.
Why is evaporative cooling good? Air itself, although always available, has worse thermodynamic properties than water. Therefore, the combination of these two factors in a cooling system allows for the best possible use of their advantages, while limiting the disadvantages. Ice water can be used for both absorption and evaporation cooling.
If there is direct contact between the water and the air, and if there is also a heat input, there is a process of non-diabatic evaporation of water into the air. Thus, there is a latent heat dissipation of the air humidifying water vapour and a sensible heat dissipation, which is absorbed by the air stream from the surface of the water itself.
An installation using chillers is a better and cheaper solution than freon air conditioning, but we must also take into account that it is more difficult to design it.