Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781260048766
Author: CENGEL
Publisher: MCG
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 5.5, Problem 43P
Somebody proposes the following system to cool a house in the summer: Compress the regular outdoor air, let it cool back to the outdoor temperature, pass it through a turbine, and discharge the cold air leaving the turbine into the house. From a
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
It is well known that the power consumed by a compressor can be reduced by cooling the gas during compression. Inspired by this, somebody proposes to cool the liquid as it flows through a pump, in order to reduce the power consumption of the pump. Would you support this proposal? Explain.
Thermodynamics
Refrigerant R-134a to the compressor of a refrigeration machine It enters at 140 kPa pressure and -10 °C, and exits at 1 MPa pressure. Volumetric flow of the refrigerant entering the compressor It is 0.23 m³/minute. The refrigerant enters the throttling valve at a pressure of 0.95 MPa and at 30 °C, and exits the evaporator as saturated steam at -18 °C. Adiabatic efficiency of the compressor It is 78%. Show the cycle in the T-s diagram. And;
a) Calculate the power required to run the compressor.
b) Calculate the heat absorbed per unit time from the cooled medium. ( COPSM=? )
c) Calculate, between the evaporator and the compressor, how much the pressure of the refrigerant drops and how much the heat gain.
Air is compressed in a two-stage, double acting acting compressor which is electrically driven at 165 rpm. The low pressure cylinder (30.5 x 35.5 cm) receives 6.85 m3/min of air at 96.53 kPaa, 43.3 C, and the high-pressure cylinder (20.3 x 35.5-cm) discharges the air at 717.06 kPaa. Piston rods are 5.1 cm in diameter and the isothermal overall efficiency is 74%. Find
a. The volumetric efficiency, %
b. The power of the driving motor, kW
c. The power savings for two-stage compressor, kW
Chapter 5 Solutions
Thermodynamics: An Engineering Approach
Ch. 5.5 - Name four physical quantities that are conserved...Ch. 5.5 - Define mass and volume flow rates. How are they...Ch. 5.5 - Does the amount of mass entering a control volume...Ch. 5.5 - Consider a device with one inlet and one outlet....Ch. 5.5 - The ventilating fan of the bathroom of a building...Ch. 5.5 - Air enters a 16-cm-diameter pipe steadily at 200...Ch. 5.5 - A steam pipe is to transport 200 lbm/s of steam at...Ch. 5.5 - A garden hose attached with a nozzle is used to...Ch. 5.5 - A steady-flow compressor is used to compress...Ch. 5.5 - Air enters the 1-m2 inlet of an aircraft engine at...
Ch. 5.5 - A 2-m3 rigid tank initially contains air whose...Ch. 5.5 - Air enters a nozzle steadily at 2.21 kg/m3 and 40...Ch. 5.5 - A spherical hot-air balloon is initially filled...Ch. 5.5 - Water enters the constant 130-mm inside-diameter...Ch. 5.5 - A desktop computer is to be cooled by a fan whose...Ch. 5.5 - A hair dryer is basically a duct of constant...Ch. 5.5 - Refrigerant-134a enters a 28-cm-diameter pipe...Ch. 5.5 - What are the different mechanisms for transferring...Ch. 5.5 - How do the energies of a flowing fluid and a fluid...Ch. 5.5 - An air compressor compresses 6 L of air at 120 kPa...Ch. 5.5 - A house is maintained at 1 atm and 24C, and warm...Ch. 5.5 - Refrigerant-134a enters the compressor of a...Ch. 5.5 - Steam is leaving a pressure cooker whose operating...Ch. 5.5 - How is a steady-flow system characterized?Ch. 5.5 - Can a steady-flow system involve boundary work?Ch. 5.5 - A diffuser is an adiabatic device that decreases...Ch. 5.5 - The kinetic energy of a fluid increases as it is...Ch. 5.5 - The stators in a gas turbine are designed to...Ch. 5.5 - The diffuser in a jet engine is designed to...Ch. 5.5 - Air enters a nozzle steadily at 50 psia, 140F, and...Ch. 5.5 - Air at 600 kPa and 500 K enters an adiabatic...Ch. 5.5 - Carbon dioxide enters an adiabatic nozzle steadily...Ch. 5.5 - Steam enters a nozzle at 400C and 800 kPa with a...Ch. 5.5 - Air at 80 kPa and 127C enters an adiabatic...Ch. 5.5 - Air at 13 psia and 65F enters an adiabatic...Ch. 5.5 - Refrigerant-134a at 700 kPa and 120C enters an...Ch. 5.5 - Refrigerant-134a enters a diffuser steadily as...Ch. 5.5 - Air at 80 kPa, 27C, and 220 m/s enters a diffuser...Ch. 5.5 - Air enters an adiabatic nozzle steadily at 300...Ch. 5.5 - Consider an adiabatic turbine operating steadily....Ch. 5.5 - Prob. 42PCh. 5.5 - Somebody proposes the following system to cool a...Ch. 5.5 - Air is expanded from 1000 kPa and 600C at the...Ch. 5.5 - Prob. 45PCh. 5.5 - Refrigerant-134a enters a compressor at 100 kPa...Ch. 5.5 - Refrigerant-134a enters a compressor at 180 kPa as...Ch. 5.5 - Steam flows steadily through an adiabatic turbine....Ch. 5.5 - Steam flows steadily through a turbine at a rate...Ch. 5.5 - Steam enters an adiabatic turbine at 8 MPa and...Ch. 5.5 - An adiabatic air compressor compresses 10 L/s of...Ch. 5.5 - Carbon dioxide enters an adiabatic compressor at...Ch. 5.5 - Steam flows steadily into a turbine with a mass...Ch. 5.5 - Air is compressed by an adiabatic compressor from...Ch. 5.5 - Air enters the compressor of a gas-turbine plant...Ch. 5.5 - A portion of the steam passing through a steam...Ch. 5.5 - Why are throttling devices commonly used in...Ch. 5.5 - Would you expect the temperature of air to drop as...Ch. 5.5 - During a throttling process, the temperature of a...Ch. 5.5 - Someone claims, based on temperature measurements,...Ch. 5.5 - Refrigerant-134a is throttled from the saturated...Ch. 5.5 - A saturated liquidvapor mixture of water, called...Ch. 5.5 - Prob. 64PCh. 5.5 - A well-insulated valve is used to throttle steam...Ch. 5.5 - Refrigerant-134a enters the expansion valve of a...Ch. 5.5 - Prob. 68PCh. 5.5 - Prob. 69PCh. 5.5 - Consider a steady-flow heat exchanger involving...Ch. 5.5 - Prob. 71PCh. 5.5 - Refrigerant-134a at 700 kPa, 70C, and 8 kg/min is...Ch. 5.5 - Hot and cold streams of a fluid are mixed in a...Ch. 5.5 - A hot-water stream at 80C enters a mixing chamber...Ch. 5.5 - Water at 80F and 20 psia is heated in a chamber by...Ch. 5.5 - An adiabatic open feedwater heater in an electric...Ch. 5.5 - Cold water (cp = 4.18 kJ/kgC) leading to a shower...Ch. 5.5 - Steam is to be condensed on the shell side of a...Ch. 5.5 - Air (cp = 1.005 kJ/kgC) is to be preheated by hot...Ch. 5.5 - An open feedwater heater heats the feedwater by...Ch. 5.5 - Refrigerant-134a at 1 MPa and 90C is to be cooled...Ch. 5.5 - The evaporator of a refrigeration cycle is...Ch. 5.5 - An air-conditioning system involves the mixing of...Ch. 5.5 - A well-insulated shell-and-tube heat exchanger is...Ch. 5.5 - Steam is to be condensed in the condenser of a...Ch. 5.5 - Steam is to be condensed in the condenser of a...Ch. 5.5 - Two streams of water are mixed in an insulated...Ch. 5.5 - Two mass streams of the same ideal gas are mixed...Ch. 5.5 - Water is heated in an insulated, constant-diameter...Ch. 5.5 - A 110-volt electrical heater is used to warm 0.3...Ch. 5.5 - The ducts of an air heating system pass through an...Ch. 5.5 - The fan on a personal computer draws 0.3 ft3/s of...Ch. 5.5 - Saturated liquid water is heated in a steady-flow...Ch. 5.5 - Water enters the tubes of a cold plate at 70F with...Ch. 5.5 - Prob. 96PCh. 5.5 - A computer cooled by a fan contains eight PCBs,...Ch. 5.5 - A desktop computer is to be cooled by a fan. The...Ch. 5.5 - Prob. 99PCh. 5.5 - A 4-m 5-m 6-m room is to be heated by an...Ch. 5.5 - A house has an electric heating system that...Ch. 5.5 - A long roll of 2-m-wide and 0.5-cm-thick 1-Mn...Ch. 5.5 - Prob. 103PCh. 5.5 - Prob. 104PCh. 5.5 - Argon steadily flows into a constant-pressure...Ch. 5.5 - Steam enters a long, horizontal pipe with an inlet...Ch. 5.5 - Refrigerant-134a enters the condenser of a...Ch. 5.5 - A hair dryer is basically a duct in which a few...Ch. 5.5 - A hair dryer is basically a duct in which a few...Ch. 5.5 - Air enters the duct of an air-conditioning system...Ch. 5.5 - An insulated rigid tank is initially evacuated. A...Ch. 5.5 - A rigid, insulated tank that is initially...Ch. 5.5 - Prob. 115PCh. 5.5 - A 2-m3 rigid tank initially contains air at 100...Ch. 5.5 - A 0.2-m3 rigid tank equipped with a pressure...Ch. 5.5 - Prob. 118PCh. 5.5 - An insulated 40-ft3 rigid tank contains air at 50...Ch. 5.5 - A 4-L pressure cooker has an operating pressure of...Ch. 5.5 - An air-conditioning system is to be filled from a...Ch. 5.5 - Oxygen is supplied to a medical facility from ten...Ch. 5.5 - A 0.05-m3 rigid tank initially contains...Ch. 5.5 - A 0.12-m3 rigid tank contains saturated...Ch. 5.5 - A 0.3-m3 rigid tank is filled with saturated...Ch. 5.5 - The air-release flap on a hot-air balloon is used...Ch. 5.5 - Prob. 127PCh. 5.5 - An insulated 0.15-m3 tank contains helium at 3 MPa...Ch. 5.5 - A vertical pistoncylinder device initially...Ch. 5.5 - A vertical piston-cylinder device initially...Ch. 5.5 - A pistoncylinder device initially contains 0.6 kg...Ch. 5.5 - The weighted piston of the device shown in Fig....Ch. 5.5 - Prob. 136RPCh. 5.5 - Prob. 137RPCh. 5.5 - Prob. 138RPCh. 5.5 - Air at 4.18 kg/m3 enters a nozzle that has an...Ch. 5.5 - Prob. 140RPCh. 5.5 - An air compressor compresses 15 L/s of air at 120...Ch. 5.5 - A steam turbine operates with 1.6 MPa and 350C...Ch. 5.5 - Refrigerant-134a enters an adiabatic compressor at...Ch. 5.5 - Prob. 144RPCh. 5.5 - Prob. 145RPCh. 5.5 - Prob. 146RPCh. 5.5 - Prob. 147RPCh. 5.5 - Steam enters a nozzle with a low velocity at 150C...Ch. 5.5 - Prob. 149RPCh. 5.5 - Prob. 150RPCh. 5.5 - Prob. 151RPCh. 5.5 - Prob. 152RPCh. 5.5 - Prob. 153RPCh. 5.5 - Cold water enters a steam generator at 20C and...Ch. 5.5 - An ideal gas expands in an adiabatic turbine from...Ch. 5.5 - Determine the power input for a compressor that...Ch. 5.5 - Prob. 157RPCh. 5.5 - Prob. 158RPCh. 5.5 - Prob. 159RPCh. 5.5 - Prob. 160RPCh. 5.5 - In a dairy plant, milk at 4C is pasteurized...Ch. 5.5 - Prob. 162RPCh. 5.5 - Prob. 163RPCh. 5.5 - Prob. 164RPCh. 5.5 - Prob. 165RPCh. 5.5 - Prob. 166RPCh. 5.5 - The average atmospheric pressure in Spokane,...Ch. 5.5 - The ventilating fan of the bathroom of a building...Ch. 5.5 - Prob. 169RPCh. 5.5 - Determine the rate of sensible heat loss from a...Ch. 5.5 - Prob. 171RPCh. 5.5 - An air-conditioning system requires airflow at the...Ch. 5.5 - A building with an internal volume of 400 m3 is to...Ch. 5.5 - The maximum flow rate of standard shower heads is...Ch. 5.5 - Prob. 176RPCh. 5.5 - Prob. 177RPCh. 5.5 - Steam enters a turbine steadily at 7 MPa and 600C...Ch. 5.5 - Reconsider Prob. 5178. Using appropriate software,...Ch. 5.5 - Prob. 180RPCh. 5.5 - A liquid R-134a bottle has an internal volume of...Ch. 5.5 - A pistoncylinder device initially contains 2 kg of...Ch. 5.5 - A pistoncylinder device initially contains 1.2 kg...Ch. 5.5 - A pressure cooker is a pot that cooks food much...Ch. 5.5 - A tank with an internal volume of 1 m3 contains...Ch. 5.5 - In a single-flash geothermal power plant,...Ch. 5.5 - An adiabatic air compressor is to be powered by a...Ch. 5.5 - The turbocharger of an internal combustion engine...Ch. 5.5 - Prob. 189RPCh. 5.5 - Consider an evacuated rigid bottle of volume V...Ch. 5.5 - An adiabatic heat exchanger is used to heat cold...Ch. 5.5 - A heat exchanger is used to heat cold water at 15C...Ch. 5.5 - An adiabatic heat exchanger is used to heat cold...Ch. 5.5 - In a shower, cold water at 10C flowing at a rate...Ch. 5.5 - Prob. 195FEPCh. 5.5 - Prob. 196FEPCh. 5.5 - Hot combustion gases (assumed to have the...Ch. 5.5 - Steam expands in a turbine from 4 MPa and 500C to...Ch. 5.5 - Steam is compressed by an adiabatic compressor...Ch. 5.5 - Refrigerant-134a is compressed by a compressor...Ch. 5.5 - Refrigerant-134a at 1.4 MPa and 70C is throttled...Ch. 5.5 - Prob. 202FEPCh. 5.5 - Prob. 203FEPCh. 5.5 - Air at 27C and 5 atm is throttled by a valve to 1...Ch. 5.5 - Steam at 1 MPa and 300C is throttled adiabatically...Ch. 5.5 - Air is to be heated steadily by an 8-kW electric...Ch. 5.5 - Saturated water vapor at 40C is to be condensed as...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- 4. Steam flows steadily through an adiabatic turbine. The inlet conditions of the steam are 4MPa, 500°C, and 80 m/s, and the exit conditions are 30 kPa, 92 percent quality, and 50 m/s. The mass flow rate of the steam is 12 kg/s. Determine: (a) the change in kinetic energy, (b) the power output, and P₁ = 4 MPa T₁ = 500°C V₁ = 80 m/s (c) the turbine inlet area. Steam m = 12 kg/s + P₂ = 30 kPa x₂ = 0.92 V₂ = 50 m/s W outarrow_forwardSolve the problem. An air compressor (an open system) receives 272 kg per min of air at 99.29 kPa and a specific volume of 0.026 m3/kg. The air flows steadiy through the compressor and is discharged at 689.5 kPa and 0.0051 m3/kg. The initial internal energy of the air is 1594 J/kg; at discharge, the internal energy is 6241 J/kg. The cooling water circulated around the cylinder carries away 4383 J/kg of air. The change in kinetic energy is 896 J/kg increase. Sketch an energy diagram. Compute the work.arrow_forwardThe approach and efficiency of cooling tower are 10 oC and 65 %, respectively. If the temperature of water leaving the tower is 27 oC, determine the temperature of water entering the tower.arrow_forward
- It is common knowledge that the temperature rises as it is compressed. An inventor thought about using this high temperature air to heat buildings. He used a compressor driven by an electric motor. The inventor claims that the compressed hot air system is 25% more efficient than a resistance heating system that provides an equivalent amount of heating. Is this claim valid, or is this just another perpetual motion machine?arrow_forwardAir is compressed in a two-stage , double-acting compressor which is electrically driven at 165 rpm. The low pressure cylinder (30.5 x 35.5-cm) receives 6.85 m3/min of air at 96.53 kPaa, 43.3°C, and the high pressure cylinder (20.3 x 35.5-cm) discharges the air at 717.06 kPa. Piston rods are 5.1 cm in diameter and the isothermal overall efficiency is 74%. Find (a) the volumetric efficiency, (b) the power of the driving motor.arrow_forwardI don't want text only handwritten otherwise I'll dislikearrow_forward
- Question 6 Steam flows steadily through an adiabatic turbine. The inlet conditions of the steam are 10 MPa, 450°C, and 80 m/s, and the exit conditions are 10 kPa, 92 percent quality, and 50 m/s. The mass flow rate of the steam is 12 kg/s. Determine (a) the change in kinetic energy (b) the power output, (c) the turbine inlet area. Answers: (a)-1.95 kJ/kg, (b) 10.2 MW, (c) 0.00447 m² P-10 MPa 7₁-450°C V₁ = 80 m/s STEAM m = 12 kg/s P₂ = 10 kPa 4,-0.92 V₂ = 50 m/s outarrow_forward4 The suction fan of a building heating system draws ambient air at 100 kPa and 30 °C into a duct of 0.8 m inlet diameter with a mass flow rate of 1.65 kg/s. Within the duct, the air gets heated by a 25.0 kW heater and flows into a manifold with discharge outlet 1 and outlet 2, each of 0.5 m in diameter. A damper is fitted to outlet 2 to adjust the flow area and regulate the air discharge through it. The air temperature and pressure at each outlet are 65 °C and 116 kPa, respectively. The elevation difference between the air inlet and the outlets is negligible. It is given that the entire duct and manifold assembly is perfectly insulated. The air is to be treated as an ideal gas with C=1.005 kJ/kg.K and R=0.287 ki/kg.K. (a) Find the air velocities at the inlet and the two discharge outlets of the heating system with the outlet 2 damper fully open. (b) Calculate the fan power consumption.arrow_forwardAir at a pressure of 100 kPa and a temperature of 20 °C enters a compressor. It exits the compressor at 400 kPa. If the compressor has an (isentropic) efficiency of 75%, what is the discharge (exit) temperature if air is considered as an ideal gas: (i) with constant specific heat capacities and (ii) with specific heat capacities that are not constant.arrow_forward
- A gas enters a turbine at an inlet state of 800 kPa. The gas expands and leaves the turbine atan outlet state of 100 kPa and 497 Celcius. The amount of heat transferred out from the turbine tothe surrounding is 10 kJ/kg. The surrounding is at a temperature of 28 Celcius. The actual workoutput from the turbine is 484 kJ/kg. Properties of the gas: R = 0.287 kJ/kg.K;cp = 1.138 kJ/kg.K; cv = 0.851 kJ/kg.K; k = 1.337; i) Write the energy balance equation for the turbine and state your assumptions.ii) Determine the temperature of the gas at the turbine inlet, K.iii) Determine the entropy generation, sgen during the expansion process, kJ/kg.K.iv) Is the expansion process possible? Briefly explain your answer.v) Determine the isentropic efficiency of the turbine, %.arrow_forwardConsider the turbocharger of an internal combustion engine. The exhaust gases enter the turbine at 450 °C at a rate of 0.02 kg/s and leave at 400 °C. Air enters the compressor at 70 °C and 95 kPa at a rate of 0.018 kg/s and leaves at 135 kPa. The compressor mechanical efficiency between the turbine and the is 95 percent (5 percent of turbine work is lost during its transmission to the compressor). Using air properties for the exhaust gases, determine (a) the air temperature at the compressor exit and (b) the isentropic efficiency of the compressor. Turbine 400 € Compressor Air, 70°C *alf votearrow_forwardAir (R = 0.3074 psia.cf/lbm.R) is compressed from 14.7 psia and 60°F to a pressure of 150 psia while heat loss rate during the steady compression is 10 Btu/lbm. The volume flow rate of the air at the inlet is 5,000 ft'/min and the power input to the compressor is 700 hp. Determine the temperature at the compressor exit in °F. (1hp = 0.7068 Btu/s) AIR %3D 10 Bru Ibmarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
Heat Transfer [Conduction, Convection, and Radiation]; Author: Mike Sammartano;https://www.youtube.com/watch?v=kNZi12OV9Xc;License: Standard youtube license