THERMODYNAMICS (LL)-W/ACCESS >CUSTOM<
9th Edition
ISBN: 9781266657610
Author: CENGEL
Publisher: MCG CUSTOM
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 8.8, Problem 14P
Saturated steam is generated in a boiler by converting a saturated liquid to a saturated vapor at 200 psia. This is done by transferring heat from the combustion gases, which are at 700°F, to the water in the boiler tubes. Calculate the wasted work potential associated with this heat transfer process. How does increasing the temperature of the combustion gases affect the work potential of the steam stream? Take T0 = 80°F and P0 = 14.7 psia.
FIGURE P8–14E
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A refrigerant plant works between temperature limits of – 5°C (in the evaporator) and 25°C (in the
condenser). The working fluid ammonia has a dryness fraction of 0.6 at entry to the compressor. If the
machine has a relative efficiency of 50%, calculate the amount of ice formed during a period of 24 hours.The ice is to be formed at 0°C from water at 20°C and 6 kg of ammonia is circulated per minute. Specific
heat of water is 4.187 kJ/kg and latent heat of ice is 335 kJ/kg.
A boiler produces 5.4 tonnes/hour of steam at a pressure of 1.5 MPa and a temperature of
350°C. Feedwater enters at a temperature of 44.5°C. At exit from the economizer part of the
boiler the temperature is 93.5°C. At exit from the evaporator part of the boiler the steam is 90
A % dry. Energy is supplied by 600 kg of coal per hour, which has a calorific value of
32 MJ/kg. The A/F ratio is 15 1. The temperature of the flue gas at exit from the the
economizer part of the boiler is 210°C. The average specific heat at constant pressure of the
in the economizer is 1045 J/kg.K. When the ambient temperature is 24°C :
7.
IS
flue
gas
7.1
Calculate the efficiency of the boiler.
[83.3 %]
Calculate the equivalent evaporation from and at 100°C per unit mass of fuel.
|11.9|
Draw up an energy balance, on a kJ/kg coal basis, with percentages of the total energy
supplied.
Jeconomizer 6.8 %, evaporator 62 %, superheater 15.5 %, to atmosphere 9.7 %, other
7.2
7.3
losses 7 %]
The condensing pressure for a Rankine engine is 1 bar (hf= 417.4 kJ/kg). Calculate the net work for 1 kg/s of steam and the thermal efficiency when the steam at the beginning of expansion is at 50 bar and (a) saturated (b) 350°C and (c) 640°C. Note the variation of efficiency and the quality at the end of the expansion.
Chapter 8 Solutions
THERMODYNAMICS (LL)-W/ACCESS >CUSTOM<
Ch. 8.8 - What final state will maximize the work output of...Ch. 8.8 - Is the exergy of a system different in different...Ch. 8.8 - Under what conditions does the reversible work...Ch. 8.8 - How does useful work differ from actual work? For...Ch. 8.8 - How does reversible work differ from useful work?Ch. 8.8 - Is a process during which no entropy is generated...Ch. 8.8 - Consider an environment of zero absolute pressure...Ch. 8.8 - It is well known that the actual work between the...Ch. 8.8 - Consider two geothermal wells whose energy...Ch. 8.8 - Consider two systems that are at the same pressure...
Ch. 8.8 - Prob. 11PCh. 8.8 - Does a power plant that has a higher thermal...Ch. 8.8 - Prob. 13PCh. 8.8 - Saturated steam is generated in a boiler by...Ch. 8.8 - One method of meeting the extra electric power...Ch. 8.8 - A heat engine that receives heat from a furnace at...Ch. 8.8 - Consider a thermal energy reservoir at 1500 K that...Ch. 8.8 - A heat engine receives heat from a source at 1100...Ch. 8.8 - A heat engine that rejects waste heat to a sink at...Ch. 8.8 - A geothermal power plant uses geothermal liquid...Ch. 8.8 - A house that is losing heat at a rate of 35,000...Ch. 8.8 - A freezer is maintained at 20F by removing heat...Ch. 8.8 - Prob. 24PCh. 8.8 - Prob. 25PCh. 8.8 - Prob. 26PCh. 8.8 - Can a system have a higher second-law efficiency...Ch. 8.8 - A mass of 8 kg of helium undergoes a process from...Ch. 8.8 - Which is a more valuable resource for work...Ch. 8.8 - Which has the capability to produce the most work...Ch. 8.8 - The radiator of a steam heating system has a...Ch. 8.8 - A well-insulated rigid tank contains 6 lbm of a...Ch. 8.8 - A pistoncylinder device contains 8 kg of...Ch. 8.8 - Prob. 35PCh. 8.8 - Prob. 36PCh. 8.8 - Prob. 37PCh. 8.8 - A pistoncylinder device initially contains 2 L of...Ch. 8.8 - A 0.8-m3 insulated rigid tank contains 1.54 kg of...Ch. 8.8 - An insulated pistoncylinder device initially...Ch. 8.8 - Prob. 41PCh. 8.8 - An insulated rigid tank is divided into two equal...Ch. 8.8 - A 50-kg iron block and a 20-kg copper block, both...Ch. 8.8 - Prob. 45PCh. 8.8 - Prob. 46PCh. 8.8 - Prob. 47PCh. 8.8 - A pistoncylinder device initially contains 1.4 kg...Ch. 8.8 - Prob. 49PCh. 8.8 - Prob. 50PCh. 8.8 - Prob. 51PCh. 8.8 - Air enters a nozzle steadily at 200 kPa and 65C...Ch. 8.8 - Prob. 54PCh. 8.8 - Prob. 55PCh. 8.8 - Argon gas enters an adiabatic compressor at 120...Ch. 8.8 - Prob. 57PCh. 8.8 - Prob. 58PCh. 8.8 - The adiabatic compressor of a refrigeration system...Ch. 8.8 - Refrigerant-134a at 140 kPa and 10C is compressed...Ch. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Combustion gases enter a gas turbine at 900C, 800...Ch. 8.8 - Steam enters a turbine at 9 MPa, 600C, and 60 m/s...Ch. 8.8 - Refrigerant-134a is condensed in a refrigeration...Ch. 8.8 - Prob. 66PCh. 8.8 - Refrigerant-22 absorbs heat from a cooled space at...Ch. 8.8 - Prob. 68PCh. 8.8 - Prob. 69PCh. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Hot combustion gases enter the nozzle of a...Ch. 8.8 - Prob. 72PCh. 8.8 - A 0.6-m3 rigid tank is filled with saturated...Ch. 8.8 - Prob. 74PCh. 8.8 - Prob. 75PCh. 8.8 - An insulated vertical pistoncylinder device...Ch. 8.8 - Liquid water at 200 kPa and 15C is heated in a...Ch. 8.8 - Prob. 78PCh. 8.8 - Prob. 79PCh. 8.8 - A well-insulated shell-and-tube heat exchanger is...Ch. 8.8 - Steam is to be condensed on the shell side of a...Ch. 8.8 - Prob. 82PCh. 8.8 - Prob. 83PCh. 8.8 - Prob. 84PCh. 8.8 - Prob. 85RPCh. 8.8 - Prob. 86RPCh. 8.8 - An aluminum pan has a flat bottom whose diameter...Ch. 8.8 - Prob. 88RPCh. 8.8 - Prob. 89RPCh. 8.8 - A well-insulated, thin-walled, counterflow heat...Ch. 8.8 - Prob. 92RPCh. 8.8 - Prob. 93RPCh. 8.8 - Prob. 94RPCh. 8.8 - Prob. 95RPCh. 8.8 - Nitrogen gas enters a diffuser at 100 kPa and 110C...Ch. 8.8 - Prob. 97RPCh. 8.8 - Steam enters an adiabatic nozzle at 3.5 MPa and...Ch. 8.8 - Prob. 99RPCh. 8.8 - A pistoncylinder device initially contains 8 ft3...Ch. 8.8 - An adiabatic turbine operates with air entering at...Ch. 8.8 - Steam at 7 MPa and 400C enters a two-stage...Ch. 8.8 - Prob. 103RPCh. 8.8 - Steam enters a two-stage adiabatic turbine at 8...Ch. 8.8 - Prob. 105RPCh. 8.8 - Prob. 106RPCh. 8.8 - Prob. 107RPCh. 8.8 - Prob. 108RPCh. 8.8 - Prob. 109RPCh. 8.8 - Prob. 111RPCh. 8.8 - A passive solar house that was losing heat to the...Ch. 8.8 - Prob. 113RPCh. 8.8 - A 4-L pressure cooker has an operating pressure of...Ch. 8.8 - Repeat Prob. 8114 if heat were supplied to the...Ch. 8.8 - Prob. 116RPCh. 8.8 - A rigid 50-L nitrogen cylinder is equipped with a...Ch. 8.8 - Prob. 118RPCh. 8.8 - Prob. 119RPCh. 8.8 - Prob. 120RPCh. 8.8 - Reconsider Prob. 8-120. The air stored in the tank...Ch. 8.8 - Prob. 122RPCh. 8.8 - Prob. 123RPCh. 8.8 - Prob. 124RPCh. 8.8 - Prob. 125RPCh. 8.8 - Prob. 126RPCh. 8.8 - Prob. 127RPCh. 8.8 - Water enters a pump at 100 kPa and 30C at a rate...Ch. 8.8 - Prob. 129RPCh. 8.8 - Prob. 130RPCh. 8.8 - Obtain a relation for the second-law efficiency of...Ch. 8.8 - Writing the first- and second-law relations and...Ch. 8.8 - Prob. 133RPCh. 8.8 - Keeping the limitations imposed by the second law...Ch. 8.8 - Prob. 135FEPCh. 8.8 - Prob. 136FEPCh. 8.8 - Prob. 137FEPCh. 8.8 - Prob. 138FEPCh. 8.8 - A furnace can supply heat steadily at 1300 K at a...Ch. 8.8 - A heat engine receives heat from a source at 1500...Ch. 8.8 - Air is throttled from 50C and 800 kPa to a...Ch. 8.8 - Prob. 142FEPCh. 8.8 - A 12-kg solid whose specific heat is 2.8 kJ/kgC is...
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
- A refrigerant plant works between temperature limits of – 5°C (in the evaporator) and 25°C (in thecondenser). The working fluid ammonia has a dryness fraction of 0.6 at entry to the compressor. If themachine has a relative efficiency of 50%, calculate the amount of ice formed during a period of 24 hours. The ice is to be formed at 0°C from water at 20°C and 6 kg of ammonia is circulated per minute. Specificheat of water is 4.187 kJ/kg and latent heat of ice is 335 kJ/kg.arrow_forwardTHERMOFLUID In steam power plants, open feedwater heaters are frequently utilized to heat the feedwater by mixing it with steam bled off the turbine at some intermediate stage. Consider an open feedwater heater that operates at a pressure of 1000 kPa. Feedwater at 50°C and 1000 kPa is to be heated with superheated steam at 200°C and 1000 kPa. In an ideal feedwater heater, the mixture leaves the heater as saturated liquid at the feedwater pressure. Determine the ratio of the mass flow rates of the feedwater and the superheated vapor for this case.arrow_forwardThis is part one of a two-part problem. Water at 2.0 kg/s enters the boiler at 40°C and 2000 kPa and exits the boiler at 2000 kPa. If the heat transfer rate into the boiler is 8 000 kW, what is the specific enthalpy (h) at the exit of the boiler? Boiler Turbinearrow_forward
- A pharmaceutical company plans to install a solid fuel fired boiler for its daily usage. The desired capacity of the steam generation is 1.25 kg per second at pressure of 1.15 MPa and temperature 215oC. Feed water at average temperature of 25oC, is to be fetched from nearby reservoir. The consumption of the solid fuel having calorific value of 25.7 MJ/kg is 375 grams per second. Evaluate the enhancement of efficiency of the boiler if the following accessories are coupled with it. i) Economizer that increases the inlet feed water temperature by 63⁰C and reduces the fuel consumption by 18%. ii) Air-preheater that reduces the fuel consumption by 26%.arrow_forwardIn 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_forwardA cyclic steam power plant is designed to supply steam from the boiler at 10 MPa and 550°C when the boiler is supplied with feed water at a temperature of 210 °C. It is estimated that the thermal efficiency of the cycle will be 38.4% when the net power output is 100 MW. Calculate the steam consumption rate ( m ̇s ). The enthalpy of the feed water may be taken as being equal to the enthalpy of saturated water at the same temperature. The boiler efficiency is 87% and the HHV of the fuel is 42500 kJ/kg. Calculate the rate of fuel consumption in kg/s ( m ̇f ) and tons/min.arrow_forward
- During the isothermal process of a cannot cycle,the working fluid experiences an entropy change of -0.7Btu/R.If the temperature of the heat sink is 95.Determine the heat transfer in KJarrow_forwardThe gaseous coal is then burned in a gas turbine, and part of the waste heat from the exhaust gases is recovered to generate steam for the steam turbine. The construction of IGCC plants costs about $1500 per kW, but their efficiency is about 48 percent. The average heating value of the coal is about 28,000,000 kJ per ton (that is, 28,000,000 kJ of heat is released when 1 ton of coal is burned). If the IGCC plant is to recover its cost difference from fuel savings in five years, determine what the price of coal should be in $ per ton.arrow_forwardSteam is to be condensed on the shell side of a heat exchanger at 120°F. Cooling water enters the tubes at 60°F at a rate of 115.3 lbm/s and leaves at 73°F. Assuming the heat exchanger to be well insulated, determine the rate of exergy destruction in the heat exchanger. Take T0 = 77°Farrow_forward
- A fuel oil is burned with air in a boiler. Combustion produces 813 kW of thermal energy (heat), 65% of which is transferred as heat to boiler tubes that pass through the furnace. Combustion products pass from the furnace to a chimney at 550°C. The water enters the boiler as a liquid at 30°C and exits as a saturated steam at 20 bar (absolute).(a) Calculate the rate (kg/h) of steam production.(b) Use the steam tables to estimate the volumetric flow of the steam produced.(c) What happens to the 35% of thermal energy released by combustion that is not used to produce steam?arrow_forwardIn a steam power plant, steam enters the turbine at 2.5 MPa and 500 C. The condenser pressure is 15 KPa. The turbine and pump isentropic efficiencies are 94 % and 89 %, respectively. Determine the actual net work in kJ/kg. In solving, use two decimal places for the enthalpies/energies while four decimal places for the steam quality. For the final answer, use two decimal placesarrow_forwardAn air conditioner with refrigerant-134a as the refrigerant is used to keep a large space at 20°C by rejecting the waste heat to the outside air at 37 °C. The room is gaining heat through the walls and the windows at a rate of 125 kJ/min while the heat generated by the computer, TV, and lights amounts to 0.7 kW. Unknown amount of heat is also generated by the people in the room. The condenser and evaporator pressures are 1200 and 500 kPa, respectively. The refrigerant is saturated liguid at the condenser exit and saturated vapor at the compressor inlet. If the refrigerant enters the compressor at a rate of 65 L/min and the isentropic efficiency of the compressor is 70%, determine (a) the temperature of the refrigerant at the compressor exit, (b) the rate of heat generated by the people in the room, (c) the COP of the air conditioner, and (d) the minimum volume flow rate of the refrigerant at the compressor inlet for the same compressor inlet and exit conditions.arrow_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 Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering 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
Extent of Reaction; Author: LearnChemE;https://www.youtube.com/watch?v=__stMf3OLP4;License: Standard Youtube License