In hot, dry climates an inexpensive alternative to air conditioning is the swamp cooler. In this device, water continuously wets porous pads through which fans blow the hot air. The air is cooled as the water evaporates. Use the information in Tables 4A.2 and 4C.1 to determine how much water must be evaporated to cool the air in a room of dimensions 4.0 m * 5.0 m * 3.0 m by 20. °C. Assume that the enthalpy of vaporization of water is the same as it is at 25 °C.

Transcribed Image Text:

TABLE 4A.2 Specific and Molar Heat Capacities of Common Materials* Molar heat capacity Cm/(J.K.mol) Material air benzene brass copper ethanol glass (Pyrex) granite marble polyethylene stainless steel water: solid liquid vapor Specific heat capacity Cs/[J. (C)g1] 1.01 1.05 0.37 0.38 2.42 0.78 0.80 0.84 2.3 0.51 2.03 4.184 2.01 136 33 111 37 75 34