THERMODYNAMICS: ENG APPROACH LOOSELEAF
9th Edition
ISBN: 9781266084584
Author: CENGEL
Publisher: MCG
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Chapter 7.13, Problem 161P
The compressed-air requirements of a plant are met by a 150-hp compressor equipped with an intercooler, an aftercooler, and a refrigerated dryer. The plant operates 6300 h/yr, but the compressor is estimated to be compressing air during only one-third of the operating hours, that is, 2100 hours a year. The compressor is either idling or is shut off the rest of the time. Temperature measurements and calculations indicate that 25 percent of the energy input to the compressor is removed from the compressed air as heat in the aftercooler. The COP of the refrigeration unit is 2.5, and the cost of electricity is $0.065/kWh. Determine the amount of energy and money saved per year as a result of cooling the compressed air before it enters the refrigerated dryer.
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It is suggested to pump 5,000 kg/h of a liquid
at 114°C and 1.1 atm abs pressure from a
reboiler of a distillation tower to a second
distillation unit without cooling the liquid before
this joins the pump in a given industrial
operation. The liquid has a density of 866 kg/
m2 and a vapor pressure of 1.1 atm at this
heat.condition. The reboiler-to-pump line has
a friction loss of 5 kN/m2.
a. To achieve a net positive suction head of 2.5
m, how far must the liquid level in the reboiler
be maintained?
b. Compute the power needed to drive the
pump if the liquid is to be elevated 5 meters,
the pressure in the second unit is atmospheri
and the discharge line friction loss is 25 kN/
m2. The pump discharge line has a velocity of
2 m/s, and the pump-motor efficiency is 65
percent.
At the beginning of a cycle using air, the pressure, volume and temperature are 550 kN/m 2 , 0.025 m 3 and 15°C, respectively. The air is heatedat constant pressure until the temperature is 204°C. It is then expanded adiabatically until the temperature becomes 120°C. The air is cooled atconstant volume to a temperature of 15°C then restored to its original volume by isothermal compression.
(a) Draw the pressure volume and temperature entropy diagram.(b) Determine for the cycle, the heat received,(c) the work done,(d) the thermal efficiency,
Take Cp =1.00 kJ/kgK, Cp /Cv =1.4
For an adiabatic air compressor that has an inlet
temperature of 300 K and exit temperature of 500 K,
what is the compressor work for air cp = 1.005
kJ/kg.K?
none of the mentioned answers
201 kW/kg
201 kJ/kg
201000 J
Chapter 7 Solutions
THERMODYNAMICS: ENG APPROACH LOOSELEAF
Ch. 7.13 - Does a cycle for which Q 0 violate the Clausius...Ch. 7.13 - Does the cyclic integral of heat have to be zero...Ch. 7.13 - Is a quantity whose cyclic integral is zero...Ch. 7.13 - Prob. 4PCh. 7.13 - Prob. 5PCh. 7.13 - How do the values of the integral 12Q/T compare...Ch. 7.13 - Prob. 7PCh. 7.13 - The entropy of a hot baked potato decreases as it...Ch. 7.13 - When a system is adiabatic, what can be said about...Ch. 7.13 - Prob. 10P
Ch. 7.13 - A pistoncylinder device contains helium gas....Ch. 7.13 - A pistoncylinder device contains nitrogen gas....Ch. 7.13 - A pistoncylinder device contains superheated...Ch. 7.13 - The entropy of steam will (increase, decrease,...Ch. 7.13 - During a heat transfer process, the entropy of a...Ch. 7.13 - Steam is accelerated as it flows through an actual...Ch. 7.13 - Heat is transferred at a rate of 2 kW from a hot...Ch. 7.13 - A completely reversible air conditioner provides...Ch. 7.13 - Heat in the amount of 100 kJ is transferred...Ch. 7.13 - In Prob. 719, assume that the heat is transferred...Ch. 7.13 - During the isothermal heat addition process of a...Ch. 7.13 - Prob. 22PCh. 7.13 - During the isothermal heat rejection process of a...Ch. 7.13 - Air is compressed by a 40-kW compressor from P1 to...Ch. 7.13 - Refrigerant-134a enters the coils of the...Ch. 7.13 - A rigid tank contains an ideal gas at 40C that is...Ch. 7.13 - A rigid vessel is filled with a fluid from a...Ch. 7.13 - A rigid vessel filled with a fluid is allowed to...Ch. 7.13 - Prob. 29PCh. 7.13 - One lbm of R-134a is expanded isentropically in a...Ch. 7.13 - Two lbm of water at 300 psia fill a weighted...Ch. 7.13 - A well-insulated rigid tank contains 3 kg of a...Ch. 7.13 - Using the relation ds = (Q/T)int rev for the...Ch. 7.13 - The radiator of a steam heating system has a...Ch. 7.13 - A rigid tank is divided into two equal parts by a...Ch. 7.13 - Prob. 36PCh. 7.13 - An insulated pistoncylinder device contains 5 L of...Ch. 7.13 - Onekg of R-134a initially at 600 kPa and 25C...Ch. 7.13 - Refrigerant-134a is expanded isentropically from...Ch. 7.13 - Refrigerant-134a at 320 kPa and 40C undergoes an...Ch. 7.13 - A rigid tank contains 5 kg of saturated vapor...Ch. 7.13 - A 0.5-m3 rigid tank contains refrigerant-134a...Ch. 7.13 - Steam enters a steady-flow adiabatic nozzle with a...Ch. 7.13 - Steam enters an adiabatic diffuser at 150 kPa and...Ch. 7.13 - R-134a vapor enters into a turbine at 250 psia and...Ch. 7.13 - Refrigerant-134a enters an adiabatic compressor as...Ch. 7.13 - The compressor in a refrigerator compresses...Ch. 7.13 - An isentropic steam turbine processes 2 kg/s of...Ch. 7.13 - Prob. 52PCh. 7.13 - Twokg of saturated water vapor at 600 kPa are...Ch. 7.13 - A pistoncylinder device contains 5 kg of steam at...Ch. 7.13 - Prob. 55PCh. 7.13 - In Prob. 755, the water is stirred at the same...Ch. 7.13 - Prob. 57PCh. 7.13 - Prob. 58PCh. 7.13 - Determine the total heat transfer for the...Ch. 7.13 - Calculate the heat transfer, in kJ/kg. for the...Ch. 7.13 - Prob. 61PCh. 7.13 - An adiabatic pump is to be used to compress...Ch. 7.13 - Prob. 63PCh. 7.13 - Prob. 64PCh. 7.13 - A 30-kg aluminum block initially at 140C is...Ch. 7.13 - A 50-kg copper block initially at 140C is dropped...Ch. 7.13 - A 30-kg iron block and a 40-kg copper block, both...Ch. 7.13 - Prob. 69PCh. 7.13 - Prob. 70PCh. 7.13 - Can the entropy of an ideal gas change during an...Ch. 7.13 - An ideal gas undergoes a process between two...Ch. 7.13 - Prob. 73PCh. 7.13 - Air is expanded from 200 psia and 500F to 100 psia...Ch. 7.13 - Prob. 75PCh. 7.13 - Air is expanded isentropically from 100 psia and...Ch. 7.13 - Which of the two gaseshelium or nitrogenhas the...Ch. 7.13 - Which of the two gasesneon or airhas the lower...Ch. 7.13 - A 1.5-m3 insulated rigid tank contains 2.7 kg of...Ch. 7.13 - An insulated pistoncylinder device initially...Ch. 7.13 - A pistoncylinder device contains 0.75 kg of...Ch. 7.13 - A mass of 25 lbm of helium undergoes a process...Ch. 7.13 - One kg of air at 200 kPa and 127C is contained in...Ch. 7.13 - An insulated rigid tank is divided into two equal...Ch. 7.13 - Air at 27C and 100 kPa is contained in a...Ch. 7.13 - Air at 3.5 MPa and 500C is expanded in an...Ch. 7.13 - Air is compressed in a pistoncylinder device from...Ch. 7.13 - Helium gas is compressed from 90 kPa and 30C to...Ch. 7.13 - Nitrogen at 120 kPa and 30C is compressed to 600...Ch. 7.13 - Five kg of air at 427C and 600 kPa are contained...Ch. 7.13 - Prob. 92PCh. 7.13 - Prob. 93PCh. 7.13 - Prob. 94PCh. 7.13 - The well-insulated container shown in Fig. P 795E...Ch. 7.13 - An insulated rigid tank contains 4 kg of argon gas...Ch. 7.13 - Prob. 97PCh. 7.13 - Prob. 98PCh. 7.13 - Prob. 99PCh. 7.13 - It is well known that the power consumed by a...Ch. 7.13 - Calculate the work produced, in kJ/kg, for the...Ch. 7.13 - Prob. 102PCh. 7.13 - Prob. 103PCh. 7.13 - Saturated water vapor at 150C is compressed in a...Ch. 7.13 - Liquid water at 120 kPa enters a 7-kW pump where...Ch. 7.13 - Water enters the pump of a steam power plant as...Ch. 7.13 - Consider a steam power plant that operates between...Ch. 7.13 - Saturated refrigerant-134a vapor at 15 psia is...Ch. 7.13 - Helium gas is compressed from 16 psia and 85F to...Ch. 7.13 - Nitrogen gas is compressed from 80 kPa and 27C to...Ch. 7.13 - Describe the ideal process for an (a) adiabatic...Ch. 7.13 - Is the isentropic process a suitable model for...Ch. 7.13 - On a T-s diagram, does the actual exit state...Ch. 7.13 - Argon gas enters an adiabatic turbine at 800C and...Ch. 7.13 - Steam at 100 psia and 650F is expanded...Ch. 7.13 - Combustion gases enter an adiabatic gas turbine at...Ch. 7.13 - Steam at 4 MPa and 350C is expanded in an...Ch. 7.13 - Prob. 120PCh. 7.13 - Prob. 121PCh. 7.13 - Refrigerant-134a enters an adiabatic compressor as...Ch. 7.13 - The adiabatic compressor of a refrigeration system...Ch. 7.13 - Prob. 125PCh. 7.13 - Argon gas enters an adiabatic compressor at 14...Ch. 7.13 - Prob. 127PCh. 7.13 - Air enters an adiabatic nozzle at 45 psia and 940F...Ch. 7.13 - An adiabatic diffuser at the inlet of a jet engine...Ch. 7.13 - Hot combustion gases enter the nozzle of a...Ch. 7.13 - The exhaust nozzle of a jet engine expands air at...Ch. 7.13 - Prob. 133PCh. 7.13 - Refrigerant-134a is expanded adiabatically from...Ch. 7.13 - A frictionless pistoncylinder device contains...Ch. 7.13 - Prob. 136PCh. 7.13 - Steam enters an adiabatic turbine steadily at 7...Ch. 7.13 - Prob. 138PCh. 7.13 - Oxygen enters an insulated 12-cm-diameter pipe...Ch. 7.13 - Water at 20 psia and 50F enters a mixing chamber...Ch. 7.13 - Prob. 141PCh. 7.13 - Prob. 142PCh. 7.13 - In a dairy plant, milk at 4C is pasteurized...Ch. 7.13 - Steam is to be condensed in the condenser of a...Ch. 7.13 - An ordinary egg can be approximated as a...Ch. 7.13 - Prob. 146PCh. 7.13 - In a production facility, 1.2-in-thick, 2-ft 2-ft...Ch. 7.13 - Prob. 148PCh. 7.13 - Prob. 149PCh. 7.13 - Prob. 150PCh. 7.13 - Prob. 151PCh. 7.13 - Prob. 152PCh. 7.13 - Prob. 153PCh. 7.13 - Liquid water at 200 kPa and 15C is heated in a...Ch. 7.13 - Prob. 155PCh. 7.13 - Prob. 157PCh. 7.13 - Prob. 158PCh. 7.13 - Prob. 159PCh. 7.13 - Prob. 160PCh. 7.13 - The compressed-air requirements of a plant are met...Ch. 7.13 - Prob. 162PCh. 7.13 - The space heating of a facility is accomplished by...Ch. 7.13 - Prob. 164PCh. 7.13 - Prob. 165PCh. 7.13 - Prob. 166PCh. 7.13 - Prob. 167RPCh. 7.13 - A refrigerator with a coefficient of performance...Ch. 7.13 - What is the minimum internal energy that steam can...Ch. 7.13 - Prob. 170RPCh. 7.13 - What is the maximum volume that 3 kg of oxygen at...Ch. 7.13 - A 100-lbm block of a solid material whose specific...Ch. 7.13 - Prob. 173RPCh. 7.13 - A pistoncylinder device initially contains 15 ft3...Ch. 7.13 - A pistoncylinder device contains steam that...Ch. 7.13 - Prob. 176RPCh. 7.13 - Prob. 177RPCh. 7.13 - Prob. 178RPCh. 7.13 - A 0.8-m3 rigid tank contains carbon dioxide (CO2)...Ch. 7.13 - Air enters the evaporator section of a window air...Ch. 7.13 - Prob. 181RPCh. 7.13 - Prob. 182RPCh. 7.13 - Prob. 183RPCh. 7.13 - Prob. 184RPCh. 7.13 - Helium gas is throttled steadily from 400 kPa and...Ch. 7.13 - Determine the work input and entropy generation...Ch. 7.13 - Prob. 187RPCh. 7.13 - Reconsider Prob. 7187. Determine the change in the...Ch. 7.13 - Prob. 189RPCh. 7.13 - Air enters a two-stage compressor at 100 kPa and...Ch. 7.13 - Three kg of helium gas at 100 kPa and 27C are...Ch. 7.13 - Steam at 6 MPa and 500C enters a two-stage...Ch. 7.13 - Prob. 193RPCh. 7.13 - Prob. 194RPCh. 7.13 - Refrigerant-134a enters a compressor as a...Ch. 7.13 - Prob. 196RPCh. 7.13 - Prob. 197RPCh. 7.13 - Prob. 198RPCh. 7.13 - Prob. 199RPCh. 7.13 - Prob. 200RPCh. 7.13 - Prob. 201RPCh. 7.13 - Prob. 202RPCh. 7.13 - Prob. 203RPCh. 7.13 - Prob. 204RPCh. 7.13 - Prob. 205RPCh. 7.13 - Prob. 206RPCh. 7.13 - Prob. 207RPCh. 7.13 - Prob. 208RPCh. 7.13 - (a) Water flows through a shower head steadily at...Ch. 7.13 - Prob. 211RPCh. 7.13 - Prob. 212RPCh. 7.13 - Prob. 213RPCh. 7.13 - Consider the turbocharger of an internal...Ch. 7.13 - Prob. 215RPCh. 7.13 - Prob. 216RPCh. 7.13 - A 5-ft3 rigid tank initially contains...Ch. 7.13 - Prob. 218RPCh. 7.13 - Show that the difference between the reversible...Ch. 7.13 - Demonstrate the validity of the Clausius...Ch. 7.13 - Consider two bodies of identical mass m and...Ch. 7.13 - Consider a three-stage isentropic compressor with...Ch. 7.13 - Prob. 223RPCh. 7.13 - Prob. 224RPCh. 7.13 - Prob. 225RPCh. 7.13 - The polytropic or small stage efficiency of a...Ch. 7.13 - Steam is condensed at a constant temperature of...Ch. 7.13 - Steam is compressed from 6 MPa and 300C to 10 MPa...Ch. 7.13 - An apple with a mass of 0.12 kg and average...Ch. 7.13 - A pistoncylinder device contains 5 kg of saturated...Ch. 7.13 - Argon gas expands in an adiabatic turbine from 3...Ch. 7.13 - A unit mass of a substance undergoes an...Ch. 7.13 - A unit mass of an ideal gas at temperature T...Ch. 7.13 - Heat is lost through a plane wall steadily at a...Ch. 7.13 - Air is compressed steadily and adiabatically from...Ch. 7.13 - Argon gas expands in an adiabatic turbine steadily...Ch. 7.13 - Water enters a pump steadily at 100 kPa at a rate...Ch. 7.13 - Air is to be compressed steadily and...Ch. 7.13 - Helium gas enters an adiabatic nozzle steadily at...Ch. 7.13 - Combustion gases with a specific heat ratio of 1.3...Ch. 7.13 - Steam enters an adiabatic turbine steadily at 400C...Ch. 7.13 - Liquid water enters an adiabatic piping system at...Ch. 7.13 - Liquid water is to be compressed by a pump whose...Ch. 7.13 - Steam enters an adiabatic turbine at 8 MPa and...Ch. 7.13 - Helium gas is compressed steadily from 90 kPa and...Ch. 7.13 - Helium gas is compressed from 1 atm and 25C to a...
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