申論題

Problem 3 (20 points)
In India, water coolers are a common alternative to air conditioners. The simplest version of such a cooler, as illustrated in the right figure, is by forcing the warm air through a box filled with straw wetted by water. The temperature of air passing through the box can be lowered for more than 10℃ at appropriate condition.

(2) A psychometric chart can be used to estimate the maxinum temperature drop of the air obtainable with such cooler. Sketch the chart with the marks on important properties (8 points) and describe how to estimate the maximum temperature drop using the chart. (4 points).