In Open water-cooling towers, the cooling water is exposed to the atmosphere. There are usually simple, efficient and economical in design. On the other hand, closed-circuit towers will completely isolate the cooling fluid from the atmosphere. This is done by putting together heat rejection equipment together with a heat exchanger in the closed-circuit tower. The closed-loop system will protect the quality of the process fluid. With this in mind, some advantages can be attributed to the use of closed-circuit cooling towers.
Performance
These towers can work at full capacity throughout the year. While at the same time ensuring the system remains consistent and clean. This is because the processing fluid in such a system is kept isolated and therefore, does not become contaminated through the air these elements would eventually soil the system if they were allowed to enter.
Expense
The initial cost of the local loop system as compared to the closed-loop system will be less. However, higher costs will be repaid in the intervening years of operation in several ways. The cleaner processing fluid with no contaminant will result in the cleaner internal surface area thereby boosting the efficiency of the components within the system. Basically, running this system will be much more economical in the long run.
Maintenance
Since the process fluid in closed circuit cooling towers has no contact at all with the environment then, only routine maintenance will be required on the heat rejection equipment. There is no need to shut down the system from time to time to clean the heat exchanger as would be the case in an open cooling tower. The clean processing fluid that runs through the system will, therefore, extend the life of the other elements of the system.
Water treatment
To maintain the quality of the process fluid up to the desired level there is a need for processes such as filtration, chemical treatment and even adding more clean water. In a closed-circuit system, several advantages are actualized; firstly, the volume of water that is recirculated for treatment is substantially reduced. Another advantage is there is a minimal treatment that is required with regard to the water. Finally, during periods of dry operation, the need for any extra makeup water is essentially eliminated.
Operational flexibility
About their operations, closed-circuit Cooling Towers have several methods of operations that would not be possible to do with open towers. The first operation is referred to as dry operation. This helps in water conservation as well as helping to conserve treatment chemicals, it also prevents icing and plume. Another type of operation that is possible with this system is known as variable pumping. Here the closed condenser water loop allows for one to engage in variable speed pumping which in turn helps to conserve energy.
Automation
The availability of controlled systems that are automatic helps in terms of being able to control the temperature of the water as well as the necessary deicing procedures. This makes the level of operations easier without using any valve.
Cold weather durability
This system has an enhanced operating performance level even when the weather is cold. This helps in reducing the operating cost all year round.