Problem 1P: What is the difference between dry air and atmospheric air? Problem 2P: What is vapor pressure? Problem 3P: What is the difference between the specific humidity and the relative humidity? Problem 4P: Can the water vapor in air be treated as an ideal gas? Explain. Problem 5P: Explain how vapor pressure of the ambient air is determined when the temperature, total pressure,... Problem 6P: Is the relative humidity of saturated air necessarily 100 percent? Problem 7P: Moist air is passed through a cooling section where it is cooled and dehumidified. How do (a) the... Problem 8P: How will (a) the specific humidity and (b) the relative humidity of the air contained in a... Problem 9P Problem 10P: Consider a tank that contains moist air at 3 atm and whose walls are permeable to water vapor. The... Problem 11P: Is it possible to obtain saturated air from unsaturated air without adding any moisture? Explain. Problem 12P: Why are the chilled water lines always wrapped with vapor barrier jackets? Problem 13P: How would you compare the enthalpy of water vapor at 20C and 2 kPa with the enthalpy of water vapor... Problem 14P: A tank contains 15 kg of dry air and 0.17 kg of water vapor at 30C and 100 kPa total pressure.... Problem 15P Problem 16P: An 8-m3 tank contains saturated air at 30C, 105 kPa. Determine (a) the mass of dry air, (b) the... Problem 17P: Determine the masses of dry air and the water vapor contained in a 90-m3 room at 93 kPa, 15C, and 50... Problem 18P: A room contains air at 85F and 13.5 psia at a relative humidity of 60 percent. Determine (a) the... Problem 19P Problem 20P Problem 21P Problem 22P: In summer, the outer surface of a glass filled with iced water often sweats. How can you explain... Problem 23P: In some climates, cleaning the ice off the windshield of a car is a common chore on winter mornings.... Problem 24P: Andy and Wendy both wear glasses. On a cold winter day, Andy comes from the cold outside and enters... Problem 25P Problem 26P Problem 27P Problem 28P: A thirsty woman opens the refrigerator and picks up a cool canned drink at 40F. Do you think the can... Problem 29P: The air in a room has a dry-bulb temperature of 26C and a wet-bulb temperature of 21C. Assuming a... Problem 31P Problem 32P Problem 33P Problem 34P: How do constant-enthalpy and constant-wet-bulb-temperature lines compare on the psychrometric chart? Problem 35P: At what states on the psychrometric chart are the dry-bulb, wet-bulb, and dew-point temperatures... Problem 36P: How is the dew-point temperature at a specified state determined on the psychrometric chart? Problem 37P: Can the enthalpy values determined from a psychrometric chart at sea level be used at higher... Problem 38P: Atmospheric air at a pressure of 1 atm and dry-bulb temperature of 30C has a relative humidity of 80... Problem 39P Problem 40P Problem 41P Problem 43P: Atmospheric air at a pressure of 1 atm and dry-bulb temperature of 28C has a dew-point temperature... Problem 44P: Reconsider Prob. 1443. Determine the adiabatic saturation temperature of the humid air. FIGURE P1444 Problem 45P: What does a modern air-conditioning system do besides heating or cooling the air? Problem 46P: How does the human body respond to (a) hot weather, (b) cold weather, and (c) hot and humid weather? Problem 47P: How does the air motion in the vicinity of the human body affect human comfort? Problem 48P: Consider a tennis match in cold weather where both players and spectators wear the same clothes.... Problem 49P Problem 50P Problem 51P Problem 52P Problem 53P: What is metabolism? What is the range of metabolic rate for an average man? Why are we interested in... Problem 54P: Why is the metabolic rate of women, in general, lower than that of men? What is the effect of... Problem 55P: What is sensible heat? How is the sensible heat loss from a human body affected by the (a) skin... Problem 56P Problem 57P Problem 58P Problem 59P Problem 60P: Repeat Prob. 1459 for an infiltration rate of 1.8 ACH. Problem 61P: An average (1.82 kg or 4.0 lbm) chicken has a basal metabolic rate of 5.47 W and an average... Problem 62P: An average person produces 0.25 kg of moisture while taking a shower and 0.05 kg while bathing in a... Problem 63P: How do relative and specific humidities change during a simple heating process? Answer the same... Problem 64P Problem 65P: Humid air at 150 kPa, 40C, and 70 percent relative humidity is cooled at constant pressure in a pipe... Problem 66P: Humid air at 40 psia, 50F, and 90 percent relative humidity is heated in a pipe at constant pressure... Problem 67P Problem 68P: Air enters a 30-cm-diameter cooling section at 1 atm, 35C, and 45 percent relative humidity at 18... Problem 69P Problem 70P Problem 71P: Why is heated air sometimes humidified? Problem 72P: Air at 1 atm, 15C, and 60 percent relative humidity is first heated to 20C in a heating section and... Problem 73P: Air at 14.7 psia, 35F, and 50 percent relative humidity is first heated to 65F in a heating section... Problem 74P: An air-conditioning system operates at a total pressure of 1 atm and consists of a heating section... Problem 75P Problem 76P: Why is cooled air sometimes reheated in summer before it is discharged to a room? Problem 77P: Atmospheric air at 1 atm, 30C, and 80 percent relative humidity is cooled to 20C while the mixture... Problem 78P: Ten thousand cubic feet per hour of atmospheric air at 1 atm and 85F with a dew-point temperature of... Problem 79P: Air enters a 40-cm-diameter cooling section at 1 atm, 32C, and 70 percent relative humidity at 120... Problem 81P: Repeat Prob. 1479 for a total pressure of 88 kPa for air. Problem 82P: On a summer day in New Orleans, Louisiana, the pressure is 1 atm: the temperature is 32C; and the... Problem 83P Problem 84P Problem 85P Problem 86P: Saturated humid air at 70 psia and 200F is cooled to 100F as it flows through a 3-in-diameter pipe... Problem 87P: Humid air is to be conditioned in a constant-pressure process at 1 atm from 39C dry bulb and 50... Problem 88P: Atmospheric air at 1 atm, 32C, and 95 percent relative humidity is cooled to 24C and 60 percent... Problem 89P Problem 90P Problem 91P: Does an evaporation process have to involve heat transfer? Describe a process that involves both... Problem 92P Problem 93P Problem 94P: Air enters an evaporative (or swamp) cooler at 14.7 psi, 95F, and 20 percent relative humidity, and... Problem 95P Problem 96P: Air at 1 atm, 20C, and 70 percent relative humidity is first heated to 35C in a heating section and... Problem 97P: Two unsaturated airstreams are mixed adiabatically. It is observed that some moisture condenses... Problem 98P: Consider the adiabatic mixing of two airstreams. Does the state of the mixture on the psychrometric... Problem 100P: Two airstreams are mixed steadily and adiabatically. The first stream enters at 35C and 30 percent... Problem 102P: A stream of warm air with a dry-bulb temperature of 36C and a wet-bulb temperature of 30C is mixed... Problem 104P Problem 105P Problem 106P: How does a natural-draft wet cooling tower work? Problem 107P: What is a spray pond? How does its performance compare to the performance of a wet cooling tower? Problem 108P: The cooling water from the condenser of a power plant enters a wet cooling tower at 40C at a rate of... Problem 109P: A wet cooling tower is to cool 60 kg/s of water from 40 to 33C. Atmospheric air enters the tower at... Problem 110P Problem 111P Problem 112P: Water at 30C is to be cooled to 22C in a cooling tower which it enters at a rate of 5 kg/s. Humid... Problem 113P Problem 114RP Problem 115RP: Determine the mole fraction of dry air at the surface of a lake whose temperature is 18C. The air at... Problem 116RP Problem 117RP Problem 118RP Problem 119RP Problem 120RP Problem 121RP Problem 122RP Problem 124RP Problem 125RP Problem 126RP Problem 128RP Problem 129RP Problem 130RP: Air enters a cooling section at 97 kPa, 35C, and 30 percent relative humidity at a rate of 6 m3/min,... Problem 131RP Problem 132RP: Atmospheric air enters an air-conditioning system at 30C and 70 percent relative humidity with a... Problem 133RP: Humid air at 101.3 kPa, 36C dry bulb and 65 percent relative humidity is cooled at constant pressure... Problem 134RP: An automobile air conditioner uses refrigerant-134a as the cooling fluid. The evaporator operates at... Problem 135RP Problem 137RP Problem 138RP: Conditioned air at 13C and 90 percent relative humidity is to be mixed with outside air at 34C and... Problem 141FEP Problem 142FEP: A 40-m3 room contains air at 30C and a total pressure of 90 kPa with a relative humidity of 75... Problem 143FEP: A room is filled with saturated moist air at 25C and a total pressure of 100 kPa. If the mass of dry... Problem 144FEP Problem 145FEP: The air in a house is at 25C and 65 percent relative humidity. Now the air is cooled at constant... Problem 146FEP Problem 147FEP: Air at a total pressure of 90 kPa, 15C, and 75 percent relative humidity is heated and humidified to... Problem 148FEP: On the psychrometric chart, a cooling and dehumidification process appears as a line that is (a)... Problem 149FEP: On the psychrometric chart, a heating and humidification process appears as a line that is (a)... Problem 150FEP: An airstream at a specified temperature and relative humidity undergoes evaporative cooling by... format_list_bulleted