Chapter 8
COOLING TOWERS
OBJECTIVES
After studying this chapter, the student will be able to:
▪ List and describe the basic components of a cooling tower.
▪ Describe the principles of heat transfer in a cooling tower system.
▪ Describe the relationship between heat exchangers and a cooling tower.
▪ Explain how an atmospheric cooling tower operates.
▪ Explain how a natural-draft cooling tower operates.
REVIEW QUESTIONS
1. Draw a diagram of a cooling tower and three heat exchangers in parallel service.
Answer: See figure in text.
2. Draw a diagram of a cooling tower and three heat exchangers in series service. Answer:
See figure in text.
3. Draw a simple atmospheric cooling tower. List and describe seven components. Answer:
See figure in text.
4. Draw a simple hyperbolic cooling tower. List the major components. Answer: See
figure in text.
What is another name for this type of tower? Answer: Chimney or natural draft.
5. Draw a simple forced-draft-cooling tower. List the components. Answer: See figure in
text.
6. Draw a simple induced-draft cooling tower with cross-flow. List components. Answer:
See figure in text.
7. Draw a simple induced-draft cooling tower with counterflow. List the components.
Answer: See figure in text.
8. Evaporative cooling accounts for what percentage of the cooling effect in a tower.
9. List five factors that affect the efficiency of a cooling tower. Answer:
a. relative humidity
b. temperature
10. What is the measurement of how much water the air has absorbed at a given temperature?
11. On what does the rate of airflow in a natural-draft cooling tower depend? Answer: Wind
12. Hyperbolic towers are designed primarily for service in what industry? Answer: Power
13. Which tower gets higher airflow: counterflow or cross-flow? Answer: Cross-flow.
14. Which tower is more efficient: counterflow or cross-flow? Answer: Counter-flow
15. Does air move faster through a forced-draft or induced-draft cooling tower? Answer:
16. Which tower is most efficient: forced-draft or induced-draft? Why? Answer:
Air flow rates in an induced draft tower are slower but heat transfer through evaporation
17. List four objectives of water treatment. To reduce or minimize; Answer:
a. Scale formation- suspended solids form deposits
18. Describe pH control on a cooling tower system. Answer: The water in the water basin
19. Describe the purpose of blowdown and illustrate how it works. Answer:
Blowdown—Draw-off or blowdown is primarily used to control the buildup or
20. Define approach to tower. Answer: Approach to the tower is defined as the temperature