Evaporative Cooling Effect from a Wet Cloth

Objective:

To experience the evaporative cooling effect from a wet cloth.

Outcome:

 Students will comprehend the cooling effect from evaporative coolers.

Requirements:

a wet cloth, sling psychrometer.

Prerequisites:

• A conceptual knowledge of evaporative cooling.
• A knowledge of how to use a sling psychrometer.

Procedure:

Step 1: Bring a wet cloth to the classroom. 

Step 2: Two students hold the wet cloth beneath the ceiling fan.

Step 3: Each student experiences the air quality and the cooling effect by standing beneath the wet cloth. 

Step 4: Conduct wet bulb and dry bulb temperature measurements of ambient air using a sling psychrometer.

Step 5: After 10 minutes, conduct wet bulb and dry bulb temperature measurements of evaporatively cooled air (air between the cloth and student) using a sling psychrometer.

Step 6: Tabulate all the values (as shown below) and compare them

Table: 

Ambient Temperature (℃)		Evaporatively Cooled Air (℃)
Dry Bulb	Wet Bulb	Dry Bulb	Wet Bulb

References:

For more on Evaporative Cooling, refer Fairconditioning’s Sustainable Cooling Technologies presentation:

http://www.fairconditioning.org/resources/#126-module-ppts-1478947081