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CHAPTER
13
Gas – Vapor Mixtures and Air-Conditioning
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FIGURE 13-1The Cp of air can be assumed to be constant at 1.005 kJ/(kg · °C) in the temperature range - 10 to 50°C with an error under 0.2 percent.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.FIGURE 13-2At temperatures below 50C, the h = constant lines coincide withthe T = constant lines in the superheated vapor region of water.
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FIGURE 13-4For saturated air, the vapor pressure is equal to the saturation pressure of water.
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FIGURE 13-5Specific humidity is the actual amount of water vapor in 1 kg of dry air, whereas relative humidity is the ratio of the actual amount of moisture in the air to the maximum amount of moisture air can hold at that temperature.
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FIGURE 13-6The enthalpy of moist (atmospheric) air is expressed per unit mass of dry air, not per unit mass of moist air.
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FIGURE 13-8Constant-pressure cooling of moist air and the dew-point temperature on the T-s diagram of water.
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FIGURE 13-11The adiabatic saturation process and its represen-tation on a T-s diagram of water.
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FIGURE 13-12A simple arrangement to measure the wet-bulb temperature.
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FIGURE 13-14Schematic for a psychrometric chart.
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FIGURE 13-15For saturated air, the dry-bulb, wet-bulb, and dew-point temperatures are identical.
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FIGURE 13-20Various air-conditioning processes.
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FIGURE 13-21During simple heating, specific humidity remains constant, but relative humidity decreases.
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FIGURE 13-22During simple cooling, specific humidity remains constant, but relative humidity increases.
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FIGURE 13-23Heating the humidification.
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FIGURE 13-24Schematic and psychrometric chartfor Example 13–5.
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FIGURE 13-25Schematic and psychrometric chart for Example 13–6.
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FIGURE 13-27Evaporative cooling.
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FIGURE 13-29When two airstreams at states 1 and 2 are mixed adiabatically, the state of the mixture lies on the straight line connecting the two states.
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FIGURE 13-31An induced-draft counterflow cooling tower.
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13-20Photo credit: Yunus Çengel
FIGURE 13-33A spray pond.
