Marine Freezing (Brine Chiller System)

Brine and seawater chiller systems are commonly used on fishing vessels to keep large catches fresh. These systems use either RSW (refrigerated seawater) or brine, which can have a high salt concentration, to effectively cool and preserve the catch until it is unloaded on shore for further processing or direct human consumption. This method helps to rapidly cool the catch to the required temperatures, ensuring its freshness and quality during transport.

Seawater is water from a sea or ocean. On average, seawater in the world’s oceans has a salinity of about 3.5%, while Brine is a high-concentration solution of salt (NaCl) in water (H2O). Commonly brine refers to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for brining foods) up to about 26%

Why is Seawater used for cooling?

Seawater is commonly used in cooling systems due to its lower freezing point compared to fresh water. When salt is added to water, it reduces the freezing temperature of the solution even further, making it ideal for use in low-temperature applications. By using seawater, the heat transfer efficiency is greatly increased, and is a cost-effective cooling solution. Sodium chloride (NaCl) is the most widely used salt in making brine solutions for cooling systems. It is readily available, cost-effective, and has a relatively low freezing point. Other salts like calcium chloride (CaCl2) and potassium chloride (KCl) can also be used for brine coolers and are suitable for applications requiring even lower temperatures.

How does the BRINE or seawater system work?

A brine or seawater(RSW) system can be used as a cooling alternative instead of glycol. The system consists of a brine or seawater cooler, compressor, evaporator, condenser, and an electrical control system, similar to a glycol refrigeration unit. The refrigerant extracts heat from the brine, turning it into gas. The gaseous refrigerant then flows to a condenser where the heat is released, causing the refrigerant to condense back into a liquid. The saltwater circulates through the cooling system and absorbs heat from the process to cool it down. The cooled brine is then sent back into the process to start the cycle again. A brine or seawater cooler is used to extract heat from the process and maintain a constant temperature. Using brine as a coolant can be cost-effective and efficient, particularly in low-temperature applications where precise temperature control is crucial.