Refrigerated Sea Water or commonly known as RSW systems are used extensively in Pakistan and globally to onboard fishing vessels. The purpose is to store large quantity of fish in RSW system. This is indeed a great technology used by cold rooms and cold chains in Pakistan due to its cost-effectiveness.

Most fishermen use freezers to store frozen fish caught from the Arabian Sea. In Pakistan, there is a huge market for fish and huge demand for a fish preservative for fresh fish products. We will discuss the role of RSWS systems in cold stores in Pakistan.

Fisherman work very hard to catch fish from the sea and carry it in boats. This becomes a primary step to evaluate the quality of fish that also influences the selling price of fish in Pakistan.

However, the use of the RSW systems is vital to overcome the weakness of the use of ice in the fish preservation on the ship. Let us explore more about this technique in this post and how RSWS systems work to improve the fish storage in cold rooms.

What is RSWS System

RSWS is a technique that ensures colling and preservation of fish in a cold chamber in a cold store. The fish is stored inside the cold room at a temperature of about -5C. This technology has emerged from advanced countries such as Canada and Sweeden.

It is the most important system that ensure water temperature control to maintain the best fish quality in cold rooms. Since fish is stored significantly in cold chains in Pakistan before it reaches the market, prefabricated house ensures the preservation to the freezing point of seawater. This ensures that the fish stored in cold stores remains fresh and its quality does not fade during transport.

How RSWS Systems Works?

RSW commonly referred to as refrigerated sea water is an ideal technology for ensuring mid-water trawling.

• RSW systems enable preservation of large catches of fish
• The system helps by cooling the entire fish catch quickly to an adequate level of temperature that helps fish storage on board over a long time
• It helps to ensure that there is no significant reduction in quality of stored fish
• It also helps to enhance the quality of fishmeal
• It helps to set higher standards and reduces quotas 

What is the RSW-Principle?

According to the RSW-principle, RSW-system works on this particular system.

The principle is as follows: Several pumps help to circulate the seawater through the tanks and the chilling system. The refrigeration system helps to chill the sea water and before it enters the tanks in the bottom.

From there, its distribution begins to the complete bottom cross-section of tanks. The water then enters again in the chilling unit of the system and passes through this. It repeats the circulation process through the system.

A good strategy is to add some feedwater to keep circulating water in a good condition. This helps to include more feedwater and also gets rid of dirty water. 

The Purpose of a Storage Tank

To cover the width of the fishing vessel, the storage tanks are normally made side by side. The purpose of their construction is to cover the width of the whole fishing vessel.

In these tanks, almost 80% of the fish and 20% if water is stored. This also relies on the type of fish stored and its size. The goal of RSWS system is to avoid the entrance of heat as much as possible. This is why these tanks are properly insulated and are also incorporated with equalizing pipes. Moreover, the interiors of these tanks are always never hard, its smoother.

Is it an Environmentally-Friendly Technology?

It absolutely is. In the top cold chain in Pakistan such as Izhar Foster, the RSW systems used are operated on different refrigerants including ammonia system.  This makes it an incredibly environmentally-friendly option. Now that you know more about how RSW systems work in prefabricated houses. Let us shed some light on why using ice for storign fish is an inadequate method in cold stores in Pakistan.