Cooling Water Systems Overview

Questions and Answers

What is a primary reason corrosion is a concern in closed recirculating cooling water systems?

Corrosion products can lead to improved water flow.

Corrosion products are not readily flushed or removed due to limited makeup water. (correct)

Corrosion products are easily flushed from the system.

Corrosion enhances the heat transfer efficiency in the system.

Which statement about open recirculating cooling water systems is accurate?

They are more suitable for smaller heat loads than closed systems.

They utilize cooling towers to release heat through evaporation. (correct)

They operate without any makeup water requirements.

They require constant addition of water to prevent leaks.

What is one disadvantage of closed recirculating cooling water systems?

They require a secondary cooling system for operation. (correct)

They require large volumes of makeup water.

They can handle larger heat loads than open systems.

They can lead to higher levels of microbiological fouling.

Why is plugging a significant issue in closed recirculating cooling water systems?

Small orifices and ports can easily become obstructed by corrosion products. Signup and view all the answers

What role does a cooling tower play in an open recirculating cooling water system?

It enhances evaporation by breaking water into droplets and creating airflow. Signup and view all the answers

What is a primary disadvantage of a once-through cooling water system?

Environmental concerns and discharge restrictions Signup and view all the answers

How does a closed recirculating cooling water system differ from a once-through cooling water system?

Water is reused and cooled multiple times Signup and view all the answers

What is the purpose of the blowdown procedure in cooling water systems?

To remove accumulated solids and impurities Signup and view all the answers

Which of the following terms is associated with the measurement of cooling water system efficiency?

Cycles of concentration Signup and view all the answers

What describes the role of a heat exchanger in a cooling water system?

It transfers heat away from the process fluid to the cooling water Signup and view all the answers

Study Notes

Learning Objectives for Cooling Water Systems

Define and explain the operation of a once-through cooling water system.
Identify advantages and disadvantages of once-through cooling water systems.
Define a closed recirculating cooling water system and its workings.
List pros and cons of closed recirculating cooling water systems.
Describe three types of cooling towers and their functions.
Explain the Blowdown procedure and its significance.
Understand key terms: temperature drop, recirculation rate, makeup water, holding capacity, time per cycle, drift, and cycles of concentration.
Define heat exchangers and explain the differing types.
Emphasize the importance of monitoring and control in cooling systems.

Cooling Water Systems Overview

Cooling water systems transfer heat between substances, commonly utilizing heat exchangers.
Hot processes involve steam, hot water, or process liquids/gases, while cold processes cool these elements.

Once-Through Cooling Water System

Water passes through heat exchangers once and is then discharged.
No recirculation keeps mineral content unchanged.
Requires large volumes of water from sources such as seawater, lakes, or rivers.

Advantages and Disadvantages

Advantages: Low initial capital costs.
Disadvantages: Environmental concerns, discharge restrictions, high water usage, and water quality degradation during dry spells.

Closed Recirculating Cooling Water System

Utilizes a fixed volume of water sealed from atmospheric exposure, minimizing evaporation.
Makeup water is only needed for leak compensation (0.1-0.5% lost per day).

Components

Pump: Circulates water in the system.
1st Heat Exchanger: Transfers heat from the process to the cooling water.
2nd Heat Exchanger: Removes heat from the cooling water loop.

Challenges

Subject to corrosion and microbiological fouling, complicating maintenance.
Corrosion can lead to buildup, plugging devices, and reduced system efficiency.

Advantages and Disadvantages

Advantages: Minimal makeup water requirement and smaller volume treatment.
Disadvantages: Needs a secondary cooling system and is limited to smaller systems.

Open Recirculating Cooling Water Systems

Open to the environment, with heat released via evaporation in cooling towers.
Efficient at handling high heat loads while recycling water to minimize waste.

Cooling Tower Functionality

Enhances evaporation by breaking water into fine droplets for better heat release.
Utilizes fans for rapid airflow to expel evaporated molecules.

Types of Cooling Towers

Natural Draft Cooling Towers
Mechanical Draft Cooling Towers
Evaporative Condenser Cooling Towers

Additional Notes

The cooling tower significantly boosts evaporation efficiency, ensuring optimal cooling performance in various industrial processes.

Description

This quiz covers the fundamentals of cooling water systems, focusing on both once-through and closed recirculating systems. You'll explore key concepts, including cooling tower types, the Blowdown procedure, and the significance of monitoring and control in these systems. Understanding these principles is essential for efficient heat transfer and system management.