A closed loop cooling system, also known as a closed circuit cooler, works by circulating a process fluid through a closed system where heat is extracted and dissipated, maintaining a consistent temperature for the equipment or process it serves. Here's a detailed breakdown:
The Basic Process
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Process Fluid Circulation: The fluid that needs cooling (e.g., water, glycol solution) is circulated through a network of pipes or coils within the closed loop cooler.
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Heat Transfer to Coils: The hot process fluid flows through the coils inside the cooler, transferring its heat to the coil material.
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External Cooling Mechanism: This is where the key process of heat removal happens. A water distribution system cascades water over the outside of the coils. As this water flows over the hot coils, it evaporates. According to the reference, ”A water distribution system cascades water over the tubes of the coil, extracting heat from the process loop via evaporation.”
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Evaporative Cooling Enhancement: To further improve the cooling process, air is drawn or forced across the coils. The airflow agitates the falling water, which significantly increases the rate of evaporation and thus, the rate of heat transfer. ”Air is drawn or forced across the coils, agitating the falling water and increasing the transfer of heat.”
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Closed Loop Recirculation: The cooled process fluid is then recirculated back to the equipment or process to absorb more heat, repeating the cycle. Importantly, the cooling water that evaporates is constantly replenished to maintain efficient cooling.
Components and Their Roles
| Component | Role |
|---|---|
| Process Fluid | The fluid being cooled. |
| Coils | Act as the heat exchanger, transferring heat from the process fluid to the external cooling water. |
| Water Distribution System | Cascades water over the coils to facilitate evaporative cooling. |
| Air Handling System (Fan) | Draws or forces air across the coils to enhance evaporation. |
| Make-Up Water Supply | Replenishes the water lost through evaporation. |
Advantages of Closed Loop Systems
- Reduced Contamination: Because the process fluid is in a closed loop, it is less susceptible to contamination compared to open systems.
- Consistent Temperature Control: Provides more stable and precise temperature control for the equipment it serves.
- Water Conservation: Although evaporation is a key cooling method, closed loop systems generally use less water than once-through cooling systems.
Example Application
Imagine a large industrial manufacturing plant that uses heavy machinery which generates a lot of heat. A closed loop cooling system might be used to circulate a coolant through the machinery to keep it from overheating. The coolant absorbs the heat, carries it to the closed loop cooler where it is cooled, and then the cooled coolant is recirculated back to the machinery.
