EBK THERMODYNAMICS: AN ENGINEERING APPR
9th Edition
ISBN: 8220106796979
Author: CENGEL
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 7.13, Problem 163P
The space heating of a facility is accomplished by natural gas heaters that are 85 percent efficient. The compressed-air needs of the facility are met by a large liquid-cooled compressor. The coolant of the compressor is cooled by air in a liquid-to-air heat exchanger whose airflow section is 1.0 m high and 1.0 m wide. During typical operation, the air is heated from 20 to 52°C as it flows through the heat exchanger. The average velocity of air on the inlet side is measured at 3 m/s. The compressor operates 20 hours a day and 5 days a week throughout the year. Taking the heating season to be 6 months (26 weeks) and the cost of the natural gas to be $1.25/therm (1 therm = 100,000 Btu = 105,500 kJ), determine how much money will be saved by diverting the compressor waste heat into the facility during the heating season.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Steam with quality 0.85 enters the condenser of a power plant at 20 kPa
with a mass flow rate 10 kg/s. It is cooled by water from a nearby river by
circulating through the tubes inside the condenser. If the steam leaves the
condenser as saturated liquid at 20 kPa and the temperature rise of the
cooling water is 15°C, (a) determine the minimum mass flow rate of the
cooling water required, (b) determine the heat transfer rate from the steam
to the cooling water. Hint: Average specific heats at room temperature
can be used for the cooling water from river.
E
Water
Saturated liquid water is heated in a heat exchanger until it exits as a saturated liquid vapor mixture. Hot oil is used to heat the water. The hot oil enters the heat exchanger at 150
C and exits at 40 C. The mass flowrate of the hot oil is 11 kg/s and has a specific heat of 2.2 kJ/kg-C. The water enters the heat exchanger at 25 C and 100 kPa. The water leaves
the heat exchanger as a saturated liquid vapor mixture at 100 kPa. The mass flowrate of the water is 1.5 kg/s.
What is the enthalpy of the water at the exit of the heat exchanger in units of kJ/kg?
Select the answer that is closest to the true value.
A) 911 B) 1234 C) 1557 D) 1879
A Moving to another question will save this response.
Question 1 of 11
Saturated liquid water is heated in a heat exchanger until it exits as a saturated liquid vapor mixture. Hot oil is used to heat the water. The hot oil enters the heat exchanger at 150
C and exits at 40 C. The mass flowrate of the hot oil is 11 kg/s and has a specific heat of 2.2 kJ/kg-C. The water enters the heat exchanger at 25 C and 100 kPa. The water leaves
the heat exchanger as a saturated liquid vapor mixture at 100 kPa. The mass flowrate of the water is 1.5 kg/s.
What is the enthalpy of the water at the exit of the heat exchanger in units of kJ/kg?
Select the answer that is closest to the true value.
A) 911 B) 1234 C) 1557 D) 1879
AMoving to another question will save this response.
Question 1 of 11
Chapter 7 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
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...
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
- In a power plant steam, steam is continuously extracted from the turbine and in a heat exchanger there is a condensation of the extracted steam. The energy released during condensation of steam is used to operate a heat engine. A heat engine receives thermal energy at a rate of 1200 kJ/min from condensing steam and rejects waste heat to a lake at 25°C at a rate of 850 kJ/min. Determine the lowest possible condensing steam temperature.arrow_forwardSaturated liquid water is heated in a heat exchanger until it exits as a saturated liquid vapor mixture. Hot oil is used to heat the water. The hot oil enters the heat exchanger at 150 C and exits at 40 C. The mass flowrate of the hot oil is 10 kg/s and has a specific heat of 2.2 kJ/kg-C. The water enters the heat exchanger at 25 C and 100 kPa. The water leaves the heat exchanger as a saturated liquid vapor mixture at 100 kPa. The mass flowrate of the water is 1.5 kg/s. It is also know that the enthalpy of the water exiting the heat exchanger is 1718.2 kJ/kg. In the question that follows, select the answer that is closest to the true value. What is the quality of the water at the exit of the heat exchanger?arrow_forwardSaturated liquid water is heated in a heat exchanger until it exits as a saturated liquid vapor mixture. Hot oil is used to heat the water. The hot oil enters the heat exchanger at 150 C and exits at 40 C. The mass flowrate of the hot oil is 5 kg/s and has a specific heat of 2.2 kJ/kg-C. The water enters the heat exchanger at 25 C and 100 kPa. The water leaves the heat exchanger as a saturated liquid vapor mixture at 100 kPa. The mass flowrate of the water is 1.5 kg/s. In the question that follows, select the answer that is closest to the true value. What is the enthalpy of the water at the exit of the heat exchanger in units of kJ/kg?arrow_forward
- 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.arrow_forwardRefrigerant 134 A enters in a condenser of a heat pump at 180 kPa and -4 0C and exits with a quality of 0.8 and the same pressure of 180 kPa. The mass flow rate of the refrigerant is 65 kg/h, and the heat pump compressor consumes 45 kJ/min of power. Determine the coefficient of performance of the heat pump. Type your answer in the first box.arrow_forwarda power plant steam, steam is continuously extractedfromthe turbine and in a heat exchanger there is a condensation of the extracted steam. The energy released during condensation of steam is used to operate a heat engine. A heat engine receives thermal energy at a rate of 1200 kJ/hr from condensing steam and rejects waste heat to a lake at 20°C at a rate of 800 kJ/hr. Determine the lowest possible condensing steam temperature.arrow_forward
- Steam enters the condenser of a steam power plant at 30 kPa, a quality of 91 % and a mass flow rate (m) of 337 kg/min . It leaves the condenser as saturated liquid at 30 kPa. It is to be cooled with water from a nearby river by circulating the water through the tubes within the condenser. To prevent thermal pollution, the river water is not allowed to be heated to a temperature above 5°C. Part A Determine the mass flow rate (m) of the cooling water. Express your answer to the nearest integer. Vol AEo In vec kg/min Submit Request Answer Part B Determine the entropy generation rate (Sgen) in the heat exchanger. Express your answer to three significant figures. vec ? kW/K Submit Request Answer 國arrow_forwardIt 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.arrow_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_forward
- In a steam-heating system, air is heated by being passed over some tubes through which steam flows steadily. Steam enters the heat exchanger at 30 psia and 400°F at a rate of 15 lbm/min and leaves at 25 psia and 212°F. Air enters at 14.7 psia and 80°F and leaves at 130°F. Determine the volume flow rate of air at the inlet.arrow_forwardA power plant produces 7000 kW of net power. Instead of furnace, hot water with mass flow rate of 200 kg/s is used as the heat source. The water enters the plant as saturated liquid-vapor mixture at 90°C with quality 0.1 and leaves the plant at 90°C as saturated liquid. If the environment temperature (heat sink) is 25°C, determine (a) the actual thermal efficiencies (b) the rate of heat rejected from this power plant and (c) maximum possible thermal efficiencies.arrow_forwardHeat is rejected from the condenser of a heat pump cycle by refrigerant-134a entering at 700 kPa and 50 ◦C at a rate of 105 kg/h and leaves as a saturated liquid. Determine (a) the temperature of R-134a at the condenser exit, (b) the volume flow rate at the exit of the condenser in L/min, (c) the COP of the heat pump if the rate of heat absorbed in the evaporator is 12,000 Btu/h.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning
Refrigeration and Air Conditioning Technology (Mi...
Mechanical Engineering
ISBN:9781305578296
Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher:Cengage Learning
Power Plant Explained | Working Principles; Author: RealPars;https://www.youtube.com/watch?v=HGVDu1z5YQ8;License: Standard YouTube License, CC-BY