Requirements for water-cooled chillers for use in heavy industry

Efficient use of cooling water with water-cooled chillers

Water consumption in heavy industry has been declining throughout Europe for many years – due to cascade flushing as well as improved circulation and recycling of cooling water, among other things. Another way to ensure efficient use of cooling water is to employ water-cooled (instead of air-cooled) chillers to provide round-the-clock air conditioning in control rooms containing electrical equipment. The main difference between air-cooled and water-cooled chillers is the medium used to cool the condenser. Air-cooled chillers only use air for cooling. For this purpose, high-flow fans are attached to the condensers, which ensure that the refrigerant cools down in the air flow. In water-cooled chillers, on the other hand, water flows through the condenser and thus dissipates the heat.

Key criterion for water-cooled chillers: corrosion resistance

All water contains dissolved salts. Generally, a distinction is made between seawater, brackish water and fresh water. While the average salt content of seawater is 3.47 %, in Germany water with a salt content of 0.1 % to 1 % is defined as brackish water. Fresh water has a salinity of less than 0.1 %. When metal comes into contact with water, an electrochemical process occurs between the metal and the oxygen dissolved in the water. The oxygen extracts electrons from the metal, which causes corrosion. As water-cooled chillers are in permanent contact with water, a corrosion-resistant design is essential for seamless 24/7 operation. This applies specifically to the coating and construction of the liquefier, condenser, evaporator and the associated pipes. In addition, care must be taken to ensure that the components in contact with cooling water, such as the shell-and-tube heat exchanger (condenser), can be easily cleaned. Otherwise, there is a risk that deposits will form over time, impairing the heat exchange and thus the efficiency of the chiller.

Split solutions are ideal for space-critical control rooms

Due to the ever-advancing automation of processes and increasing number of electrical installations, many control rooms have extremely limited space. Therefore, when planning a professional air-conditioning system for these areas, it is imperative to pay careful attention to the correct dimensioning of the respective industrial cooling systems. So-called split air-conditioning solutions have proven highly successful in such cases. These are special water-cooled chillers in which the machine part, i.e. the compressor and shell-and-tube exchanger, is spatially separated from the air-conditioning part (fan and evaporator). This allows the installation of water-cooled refrigeration systems even in smaller control rooms and areas with small entrance doors.