EBK THERMODYNAMICS: AN ENGINEERING APPR
8th Edition
ISBN: 9780100257054
Author: CENGEL
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 10.9, Problem 112RP
Show that the thermal efficiency of a combined gas–steam power plant ηcc can be expressed as
where ηg = Wg /Qin and ηs = Ws/Qg,out are the thermal efficiencies of the gas and steam cycles, respectively. Using this relation, determine the thermal efficiency of a combined power cycle that consists of a topping gas-turbine cycle with an efficiency of 40 percent and a bottoming steam-turbine cycle with an efficiency of 30 percent.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
If the efficiencies of a power
plant, turbine and generator (in
the power plant) are 0.36, 0.5
and 0.9 respectively, then the
thermal energy produced from
95*10^5 Cal of coal in the boiler
is
kcal
---
O 7600
O 11875
76*10^5
O 118.8*10^5
You are an operating engineer in a steam power plant which is working on a regenerative Rankine cycle and you are requested to find the thermal efficiency of this cycle. You read the following data from the measuring devices used in the power plant:
The pressure and temperature of the steam at the inlet of the turbine are 7000kPa and 550 °C, respectively.
The pressure at the inlet of the condenser is 22 kPa.
The extracted steam from the turbine is at 500 kPa and it is used to heat the
feed water in an open feed water heater.
The pumps and turbine efficiencies are 80% and 85%, respectively. Don't forget to show the evele on a T-s diagram.
A power cycle operates between two thermal reservoirs at 300 K and 800 K. The working fluid of the cycle is air, which can be considered to be an ideal gas. Specific heats are not assumed to be constant. An inventor claims that for a heat input of 250 kJ, the net work from the cycle is 80 kJ. The work generating component in the cycle is a reversible, steady state turbine. The inlet pressure and temperature are 1000 kPa and 600 K and the exit temperature is 550 K. The turbine receives 150 kJ/kg of heat from the high temperature reservoir and loses 10 kJ/kg of heat to the ambient at 298 K. (a) Prove whether or not the overall cycle is possible using second law arguments. (b) determine the work done by the turbine [kJ/kg]
Chapter 10 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
Ch. 10.9 - Why is the Carnot cycle not a realistic model for...Ch. 10.9 - Prob. 2PCh. 10.9 - A steady-flow Carnot cycle uses water as the...Ch. 10.9 - A steady-flow Carnot cycle uses water as the...Ch. 10.9 - Consider a steady-flow Carnot cycle with water as...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - How do actual vapor power cycles differ from...Ch. 10.9 - The entropy of steam increases in actual steam...
Ch. 10.9 - Is it possible to maintain a pressure of 10 kPa in...Ch. 10.9 - 10–12 A steam power plant operates on a simple...Ch. 10.9 - 10–13 Refrigerant-134a is used as the working...Ch. 10.9 - 10–14 A simple ideal Rankine cycle which uses...Ch. 10.9 - 10–15E A simple ideal Rankine cycle with water as...Ch. 10.9 - Consider a 210-MW steam power plant that operates...Ch. 10.9 - Consider a 210-MW steam power plant that operates...Ch. 10.9 - A steam Rankine cycle operates between the...Ch. 10.9 - A steam Rankine cycle operates between the...Ch. 10.9 - Prob. 20PCh. 10.9 - Prob. 21PCh. 10.9 - A simple Rankine cycle uses water as the working...Ch. 10.9 - The net work output and the thermal efficiency for...Ch. 10.9 - A binary geothermal power plant uses geothermal...Ch. 10.9 - Consider a coal-fired steam power plant that...Ch. 10.9 - Show the ideal Rankine cycle with three stages of...Ch. 10.9 - How do the following quantities change when a...Ch. 10.9 - Consider a simple ideal Rankine cycle and an ideal...Ch. 10.9 - An ideal reheat Rankine cycle with water as the...Ch. 10.9 - 10–31 A steam power plant operates on the ideal...Ch. 10.9 - Steam enters the high-pressure turbine of a steam...Ch. 10.9 - 10–34 Consider a steam power plant that operates...Ch. 10.9 - A steam power plant operates on an ideal reheat...Ch. 10.9 - Consider a steam power plant that operates on a...Ch. 10.9 - Repeat Prob. 1041 assuming both the pump and the...Ch. 10.9 - Prob. 39PCh. 10.9 - How do open feedwater heaters differ from closed...Ch. 10.9 - How do the following quantities change when the...Ch. 10.9 - Prob. 43PCh. 10.9 - 10–44 The closed feedwater heater of a...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - 10–47 A steam power plant operates on an ideal...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider an ideal steam regenerative Rankine cycle...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - Repeat Prob. 1060, but replace the open feedwater...Ch. 10.9 - 10–57 An ideal Rankine steam cycle modified with...Ch. 10.9 - Prob. 58PCh. 10.9 - Prob. 59PCh. 10.9 - Prob. 60PCh. 10.9 - Consider a steam power plant that operates on a...Ch. 10.9 - Prob. 63PCh. 10.9 - Prob. 64PCh. 10.9 - The schematic of a single-flash geothermal power...Ch. 10.9 - Prob. 66PCh. 10.9 - Prob. 67PCh. 10.9 - Consider a cogeneration plant for which the...Ch. 10.9 - Prob. 69PCh. 10.9 - A large food-processing plant requires 1.5 lbm/s...Ch. 10.9 - Steam is generated in the boiler of a cogeneration...Ch. 10.9 - Consider a cogeneration power plant modified with...Ch. 10.9 - Steam is generated in the boiler of a cogeneration...Ch. 10.9 - Prob. 75PCh. 10.9 - Why is the combined gassteam cycle more efficient...Ch. 10.9 - The gas-turbine portion of a combined gassteam...Ch. 10.9 - Prob. 78PCh. 10.9 - Prob. 80PCh. 10.9 - Consider a combined gassteam power plant that has...Ch. 10.9 - Why is steam not an ideal working fluid for vapor...Ch. 10.9 - Prob. 86PCh. 10.9 - What is the difference between the binary vapor...Ch. 10.9 - Why is mercury a suitable working fluid for the...Ch. 10.9 - By writing an energy balance on the heat exchanger...Ch. 10.9 - Steam enters the turbine of a steam power plant...Ch. 10.9 - Prob. 91RPCh. 10.9 - A steam power plant operates on an ideal Rankine...Ch. 10.9 - Consider a steam power plant operating on the...Ch. 10.9 - Consider a steam power plant that operates on a...Ch. 10.9 - Repeat Prob. 1098 assuming both the pump and the...Ch. 10.9 - Consider an ideal reheatregenerative Rankine cycle...Ch. 10.9 - Prob. 97RPCh. 10.9 - Prob. 98RPCh. 10.9 - A textile plant requires 4 kg/s of saturated steam...Ch. 10.9 - Consider a cogeneration power plant that is...Ch. 10.9 - Prob. 101RPCh. 10.9 - Reconsider Prob. 10105E. It has been suggested...Ch. 10.9 - Reconsider Prob. 10106E. During winter, the system...Ch. 10.9 - Prob. 104RPCh. 10.9 - Prob. 105RPCh. 10.9 - Prob. 106RPCh. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - Show that the thermal efficiency of a combined...Ch. 10.9 - Prob. 113RPCh. 10.9 - Starting with Eq. 1020, show that the exergy...Ch. 10.9 - A solar collector system delivers heat to a power...Ch. 10.9 - Consider a simple ideal Rankine cycle. If the...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Prob. 120FEPCh. 10.9 - A simple ideal Rankine cycle operates between the...Ch. 10.9 - Prob. 122FEPCh. 10.9 - Prob. 123FEPCh. 10.9 - Consider a combined gas-steam power plant. Water...Ch. 10.9 - Pressurized feedwater in a steam power plant is to...Ch. 10.9 - Consider a steam power plant that operates on the...
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) the net heat energy absorbed during a cyclic process (the difference between heat flowing into the system and heat leaving the system) is the work. If we regard the atmosphere as a heat engine, what is the work being done by the atmosphere? That is, what phenomenon or phenomena are a realization of the work being done by the atmosphere? (B) Of all possible heat engines, the Carnot cycle has the maximum efficiency between any two operating temperatures (think of these temperatures as the maximum and minimum temperatures encountered during the cycle). Estimate the Carnot efficiency of Earth's atmosphere. [Hint: Think about the temperature variation with latitude.] (C) Do you think the efficiency of the real atmosphere would be "close" or "far" from the Carnot efficiency? Please explain your answer.arrow_forwardA steam power plant operates on a Rankine cycle as shown. If all kinetic and potential energy changes are negligible, the turbine inlet temperature is 573K, Determine the turbine power output (kJ/kg) of the plant. 3 MPa 50 LPaarrow_forwardGaseous nitrogen actuates a Carnot power cycle in which the respective volumes at the four corners of the cycle, starting at the beginning of the isothermal expansion, are V1= 10.10 L, V2= 14.53 L, V3= 226.54 L, and V4= 157.73 L. The cycle receives 21.1 kJ of heat. Determine the work, and the mean effective pressure. 65 kPa 3600 J 64.91 Pa 14.05 kJ 64.91 kPa 14.05 J 65 Pa 3600 kJ Other: O Oarrow_forward
- In a simple Rankine cycle, the steam throttled condition is 8 MPa and 480°C. The steam is then reheated to 2 MPa and 460 °C. If turbine exhaust is 60 °C, determine the following: a. Heat Added b. Turbine Work c. Heat Rejected d. Pump Work e. Net Work f. Efficiencyarrow_forwardYou are an operating engineer in a steam power plant which is working on a regenerative Rankine cycle and you are requested to find the thermal efficiency of this cycle. You read the following data from the measuring devices used in the power plant: The pressure and temperature of the steam at the inlet of the turbine are 7000kPa and 550°C, respectively. The pressure at the inlet of the condenser is 22 kPa. The extracted steam from the turbine is at 500 kPa and it is used to heat the feed water in an open feed water heater. - The pumps and turbine efficiencies are 80% and 85%, respectively. Don't forget to show the cvele on a T-s diagram.arrow_forwardWhat is the maximum thermal efficiency possible for a power cycle operating between 600°C and 110°C? (A) 47% (B) 56% (C) 63% (D) 74%arrow_forward
- A 20 mw steam power plant working on a rankine cycle operates between pressures of 80 bar and 0.1 bar. The maximum cycle temperature is 600 °c if the steam turbine efficiency is 90% calculate thermal efficiency of the cycle and mass flow rate of the steam.arrow_forwardA Carnot cycle has a thermal efficiency of 32%. If the work developed is 1000 watt-hour, determine the heat supplied. Group of answer choices 670 665 680 650arrow_forwardIn a closed cycle gas turbine there is two stage compressor and two - stage turbine. All the components are mounted on the same shaft. The pressure and temperature of air at inlet to the first stage compressor are 1.5 bar and 20 °C respectively . The maximum cycle pressure and temperature are limited to 750 ° C and 6 bar. A perfect intercooling and reheating are used between the compressors and the turbines. A regenerator whose effectiveness is 0.7 was employed. Assuming the compressors and turbines efficiencies as 0.82 , calculate : a . Thermal efficiency of the cycle. b. Mass of working fluid for a power output of 350 kW. Assume the working fluid is air has c = 1.005 kJ / kg K , y = 1.4arrow_forward
- A 25 MW Gas Turbine power plant operating on a simple open cycle system gives the following data: Air inlet temperature = 300 K Air inlet pressure = 101.325 kPa Pressure ratio = 4 Temperature after combustion = 1150 K Compressor adiabatic efficiency = 92% Compressor mechanical efficiency = 87% Turbine mechanical efficiency = 80% Generator efficiency = 96 % Heating value = 41,680 kJ/kg Combustion losses = 10% For air and gas mixture, Cp = 1.005 kJ/kg – K, R = 282 J/kg-K Determine: The actual temperature entering the combustor in K. Fuel air ratio Fuel consumption in kg/s The volume of air supplied in CFM.arrow_forwardAs a mechanical engineer in a power station working on a regenerative gas turbine, you are requested to study the performance of the cycle at which this gas turbine is working. Your supervisor informed you that the properties of the working fluid are changing with temperature and provided you with the following data; Ratio between compressor exit and inlet pressures = 9,Minimum temperature = 330 K, Maximum temperature = 1300 K, Compressor isentropic efficiency = 80 percent, Turbine isentropic efficiency = 90 percent, Regenerator effectiveness = 70 percent. Send a short report to your supervisor :including the following information The temperature at the exit of the gas %3D %3D а. turbine b. The net output work of the gas turbine c. The thermal Efficiency of the gas turbine If the efficiency of the gas turbine is low, use your own language to explain how (OJstzo xi Jlauw.) .to improve it d.arrow_forwardThe Carnot engine operates on an ideal gas using the Carnot cycle shown in thefigure below. Using the first law of thermodynamics, we determine the thermalefficiency, specific heat impute (q), and work output (w) of each operating cycle,assuming that the internal energy does not change. (K =1.4 & R = 0.287 KJ / Kg. K)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
Power Plant Explained | Working Principles; Author: RealPars;https://www.youtube.com/watch?v=HGVDu1z5YQ8;License: Standard YouTube License, CC-BY