Exercises

 

 

 

 

 

 

 

 

 

 

Cooling towers

You will recall the operation of the psychrometer that we examined in the last chapter. A cooling tower is in effect, nothing more than an enormous psychrometer.

The tower fan is an essential component, producing a strong air current that causes the warm air running over the packing to evaporate, and therefore makes it cooler.

 If the fan is not operating, the hot water no longer comes into contact with enough air to produce adequate evaporation, and cooling does not take place. The capacity of the tower is very low under these circumstances.

 On the other hand, if the wet-bulb temperature of the external air is very low, the water will be adequately cooled. The capacity of the tower is then at a maximum. However, if the water is too cold at the condenser inlet, the HP can fall dramatically (see: problem of compressor start-up with low external temperatures, page 233.)

EXERCISE : This means that a thermostat to control fan operation is installed.

1) Where should the thermostat bulb be located?

At point A: where water enters the tower?

At point B: where air leaves the tower?

At point C: where water leaves the tower?

At point D: to measure the external temperature?

2)  At what temperature should the thermostat stop the fan?

(Solution : Refrepair Manual pages 506 to 510)

 
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