Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781260048766
Author: CENGEL
Publisher: MCG
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Chapter 14.7, Problem 33P
To determine
The relative humidity and specific humidity of the air.
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The air conditions at the intake of an air compressor are 29 C, 50 percent relative humidity, and 101 kPa. The air is compressed to 400 kPa, then sent to an intercooler. If condensation of water vapor from the compressed air is to be prevented, what is the minimum temperature (tdp) to which the air can be cooled in the intercooler?Use theoretical calculation for this problem.
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Chapter 14 Solutions
Thermodynamics: An Engineering Approach
Ch. 14.7 - What is the difference between dry air and...Ch. 14.7 - What is vapor pressure?Ch. 14.7 - What is the difference between the specific...Ch. 14.7 - Can the water vapor in air be treated as an ideal...Ch. 14.7 - Explain how vapor pressure of the ambient air is...Ch. 14.7 - Is the relative humidity of saturated air...Ch. 14.7 - Moist air is passed through a cooling section...Ch. 14.7 - How will (a) the specific humidity and (b) the...Ch. 14.7 - Prob. 9PCh. 14.7 - Consider a tank that contains moist air at 3 atm...
Ch. 14.7 - Is it possible to obtain saturated air from...Ch. 14.7 - Why are the chilled water lines always wrapped...Ch. 14.7 - How would you compare the enthalpy of water vapor...Ch. 14.7 - A tank contains 15 kg of dry air and 0.17 kg of...Ch. 14.7 - Prob. 15PCh. 14.7 - An 8-m3 tank contains saturated air at 30C, 105...Ch. 14.7 - Determine the masses of dry air and the water...Ch. 14.7 - A room contains air at 85F and 13.5 psia at a...Ch. 14.7 - Prob. 19PCh. 14.7 - Prob. 20PCh. 14.7 - Prob. 21PCh. 14.7 - In summer, the outer surface of a glass filled...Ch. 14.7 - In some climates, cleaning the ice off the...Ch. 14.7 - Andy and Wendy both wear glasses. On a cold winter...Ch. 14.7 - Prob. 25PCh. 14.7 - Prob. 26PCh. 14.7 - Prob. 27PCh. 14.7 - A thirsty woman opens the refrigerator and picks...Ch. 14.7 - The air in a room has a dry-bulb temperature of...Ch. 14.7 - Prob. 31PCh. 14.7 - Prob. 32PCh. 14.7 - Prob. 33PCh. 14.7 - How do constant-enthalpy and...Ch. 14.7 - At what states on the psychrometric chart are the...Ch. 14.7 - How is the dew-point temperature at a specified...Ch. 14.7 - Can the enthalpy values determined from a...Ch. 14.7 - Atmospheric air at a pressure of 1 atm and...Ch. 14.7 - Prob. 39PCh. 14.7 - Prob. 40PCh. 14.7 - Prob. 41PCh. 14.7 - Atmospheric air at a pressure of 1 atm and...Ch. 14.7 - Reconsider Prob. 1443. Determine the adiabatic...Ch. 14.7 - What does a modern air-conditioning system do...Ch. 14.7 - How does the human body respond to (a) hot...Ch. 14.7 - How does the air motion in the vicinity of the...Ch. 14.7 - Consider a tennis match in cold weather where both...Ch. 14.7 - Prob. 49PCh. 14.7 - Prob. 50PCh. 14.7 - Prob. 51PCh. 14.7 - Prob. 52PCh. 14.7 - What is metabolism? What is the range of metabolic...Ch. 14.7 - Why is the metabolic rate of women, in general,...Ch. 14.7 - What is sensible heat? How is the sensible heat...Ch. 14.7 - Prob. 56PCh. 14.7 - Prob. 57PCh. 14.7 - Prob. 58PCh. 14.7 - Prob. 59PCh. 14.7 - Repeat Prob. 1459 for an infiltration rate of 1.8...Ch. 14.7 - An average (1.82 kg or 4.0 lbm) chicken has a...Ch. 14.7 - An average person produces 0.25 kg of moisture...Ch. 14.7 - How do relative and specific humidities change...Ch. 14.7 - Prob. 64PCh. 14.7 - Humid air at 150 kPa, 40C, and 70 percent relative...Ch. 14.7 - Humid air at 40 psia, 50F, and 90 percent relative...Ch. 14.7 - Prob. 67PCh. 14.7 - Air enters a 30-cm-diameter cooling section at 1...Ch. 14.7 - Prob. 69PCh. 14.7 - Prob. 70PCh. 14.7 - Why is heated air sometimes humidified?Ch. 14.7 - Air at 1 atm, 15C, and 60 percent relative...Ch. 14.7 - Air at 14.7 psia, 35F, and 50 percent relative...Ch. 14.7 - An air-conditioning system operates at a total...Ch. 14.7 - Prob. 75PCh. 14.7 - Why is cooled air sometimes reheated in summer...Ch. 14.7 - Atmospheric air at 1 atm, 30C, and 80 percent...Ch. 14.7 - Ten thousand cubic feet per hour of atmospheric...Ch. 14.7 - Air enters a 40-cm-diameter cooling section at 1...Ch. 14.7 - Repeat Prob. 1479 for a total pressure of 88 kPa...Ch. 14.7 - On a summer day in New Orleans, Louisiana, the...Ch. 14.7 - Prob. 83PCh. 14.7 - Prob. 84PCh. 14.7 - Prob. 85PCh. 14.7 - Saturated humid air at 70 psia and 200F is cooled...Ch. 14.7 - Humid air is to be conditioned in a...Ch. 14.7 - Atmospheric air at 1 atm, 32C, and 95 percent...Ch. 14.7 - Prob. 89PCh. 14.7 - Prob. 90PCh. 14.7 - Does an evaporation process have to involve heat...Ch. 14.7 - Prob. 92PCh. 14.7 - Prob. 93PCh. 14.7 - Air enters an evaporative (or swamp) cooler at...Ch. 14.7 - Prob. 95PCh. 14.7 - Air at 1 atm, 20C, and 70 percent relative...Ch. 14.7 - Two unsaturated airstreams are mixed...Ch. 14.7 - Consider the adiabatic mixing of two airstreams....Ch. 14.7 - Two airstreams are mixed steadily and...Ch. 14.7 - A stream of warm air with a dry-bulb temperature...Ch. 14.7 - Prob. 104PCh. 14.7 - Prob. 105PCh. 14.7 - How does a natural-draft wet cooling tower work?Ch. 14.7 - What is a spray pond? How does its performance...Ch. 14.7 - The cooling water from the condenser of a power...Ch. 14.7 - A wet cooling tower is to cool 60 kg/s of water...Ch. 14.7 - Prob. 110PCh. 14.7 - Prob. 111PCh. 14.7 - Water at 30C is to be cooled to 22C in a cooling...Ch. 14.7 - Prob. 113PCh. 14.7 - Prob. 114RPCh. 14.7 - Determine the mole fraction of dry air at the...Ch. 14.7 - Prob. 116RPCh. 14.7 - Prob. 117RPCh. 14.7 - Prob. 118RPCh. 14.7 - Prob. 119RPCh. 14.7 - Prob. 120RPCh. 14.7 - Prob. 121RPCh. 14.7 - Prob. 122RPCh. 14.7 - Prob. 124RPCh. 14.7 - Prob. 125RPCh. 14.7 - Prob. 126RPCh. 14.7 - Prob. 128RPCh. 14.7 - Prob. 129RPCh. 14.7 - Air enters a cooling section at 97 kPa, 35C, and...Ch. 14.7 - Prob. 131RPCh. 14.7 - Atmospheric air enters an air-conditioning system...Ch. 14.7 - Humid air at 101.3 kPa, 36C dry bulb and 65...Ch. 14.7 - An automobile air conditioner uses...Ch. 14.7 - Prob. 135RPCh. 14.7 - Prob. 137RPCh. 14.7 - Conditioned air at 13C and 90 percent relative...Ch. 14.7 - Prob. 141FEPCh. 14.7 - A 40-m3 room contains air at 30C and a total...Ch. 14.7 - A room is filled with saturated moist air at 25C...Ch. 14.7 - Prob. 144FEPCh. 14.7 - The air in a house is at 25C and 65 percent...Ch. 14.7 - Prob. 146FEPCh. 14.7 - Air at a total pressure of 90 kPa, 15C, and 75...Ch. 14.7 - On the psychrometric chart, a cooling and...Ch. 14.7 - On the psychrometric chart, a heating and...Ch. 14.7 - An airstream at a specified temperature and...
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- Saturated air at 20°C at a rate of 70 m /min is mixed adiabatically with the outside air at 35°C and 50% RH at a rate of 30 m3 /min. Assuming that the mixing process occurs at a pressure of 1 atrn, determine the specific humidity, the relative humidity, and dry bulb temperature and volume flow rate of the mixture.arrow_forwardAir with a total pressure of 101.3 kPa, a temperature of 12 °C and a relative humidity of 75% is both heated and humidified by water vapor. The exit conditions from the system are 25°C temperature and 75% relative humidity. If the flow rate of dry air is 1.9 kg/s, how much kg/s should the flow of steam be given to the air?arrow_forwardThe outside air is cooled by passing it through a cooling coil at 37°C and 0.70 relative humidity, and comes out as saturated air at 22°C and some moisture is taken by condensation. After this process, the cooled outdoor air is mixed with the return air at 27°C and 0.45 relative humidity. The ratio of return air to outside air is ¼ as dry air mass flow rates. It is assumed that the pressure remains constant at P=100 kPa. *Calculate the enthalpy, specific humidity, absolute humidity and temperature values of the air after mixing. (I would appreciate it if you could write the answers with the keyboard so that I can understand thanks)arrow_forward
- A bedroom is to be conditioned that the total heat load is 20 kW and the sensible heat ratio is 0.4. The room is to be maintained at 22°C DB and 55% relative humidity. The outside air condition is at 32°C DB and 23°C WB. The conditioned air from the reheater enters the room at 17°C. Determine the following: a. The percentage of recirculated air if the mass flow rate of water vapor in the mixture is 1 kg/min b. The refrigeration load TR c. The heat required in the reheater kWarrow_forwardAn air-conditioning system operates at a total pressure of 1 atm and consists of a heating section and an evaporative cooler. Air enters the heating section at 15OC and 55 percent relative humidity at a rate of 30 m3 /min, and it leaves the evaporative cooler at 25OC and 45 percent relatively humidity. Determine the TOR.arrow_forwardAn air-conditioner cools a flow of ambient moist air at 30°C and 80% relative humidity with 0.24 kg/s flow. The exit temperature is 12°C and 40% relative humidity. Pressure is at 100 kPa throughout the system. Condensed water from the moist air intake leaves the air-conditioner at a temperature of 6°C. Find the flow rate of water from the system and the amounts of heat transfer rates needed to condense the water, cool the water vapor, cool the air, and the total heat transfer rate.arrow_forward
- One m3/s of air at 12°C and 50% RH is heated and humidified using saturated steam at 100 °C to a final state of 38°C and 50% relative humidity. Sketch the process on the psychrometric chart and calculate the following: (a) Mass flow rate (b) Steam flow rate needed (c) Heating coil capacityarrow_forward8. Moist air undergoes a heating and humidification process at a pressure of 101.325 kPa from an initial state of 15°C db and 90% relative humidity to a final state at 22°C and 70% relative humidity. If the mass flow rate of the air at the initial state is 24.5 kg da/s, what is the increase in the water content of the air? Express your answer in kg/s. In your written solution, draw the process in the psychrometric chart, show the initial and final state and the values obtained from the chart.arrow_forwardSaturated ambient air with a db-temperature of 5°C and a mass flow rate of 0.9 kg/s is divided into two streams. One stream passes through a heating section and leaves it with a relative humidity of 25%. The conditions of the other stream that bypasses the heater remains unchanged. The two streams are then mixed to produce the supply air stream at 24°C. The pressure is constant at 101.3 kPa. -Determine the partial pressure of water vapor of the heated air in kPa.-The heat input by the heating coil in kW.-The mass flow of air through the bypass section in kg/s.arrow_forward
- Can you make a schematic diagram for this problem? 600 lps of air at 30°C dry-bulb and 22°C wet-bulb temperatures is heated to a temperature of 45°C and enters the dryer. The air leaves the dryer adiabatically and its relative humidity is 70%. Determine: (a.) The water evaporated kg/hr; (b.) The volume air leaving the dryer in cu.m/min; and (c.) kJ requirement of the dryer per kg of water evaporated.arrow_forwardHumid air at 40°C and 20% relative humidity enters an adiabatic spray chamber at a rate of 100 m³/hr. The air is adiabatically humidified to 50% relative humidity. Use humidity charts to find the following: • Outlet temperature of the humidified air • Rate of water evaporation in the spray chamber Water In (Liq) Cool Air T= ? Out h, = 50% V = 100 m3/hr Hot Air In T= 40°C h, = 20% Water Out (Liq)arrow_forwardSaturated air at 13 °C and 1 atm enters the heating section of an air-conditioning system at a rate of 0.5 kg/s and leaves 30 °C. Determine the rate of heat transfer to the air and the exit relative humidity.arrow_forward
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