Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 2.8, Problem 54P
Can the combined turbine–generator efficiency be greater than either the turbine efficiency or the generator efficiency? Explain.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
1)Can the combined turbine-generator efficiency be greater than either the turbine efficiency or the generator efficiency? Explain
2) On a hot summer day, a student turns his fan on when he leaves his room in the morning. When he returns in the evening, will the room be warmer or cooler than the neighboring rooms? Why? Assume all the doors and windows are kept closed.
3) Water is being heated in a closed pan on top of a range while being stirred by a paddle wheel. During the process, 30 kJ of heat is transferred to the water, and 5 kJ of heat is lost to the surrounding air. The paddle-wheel work amounts to 500 N · m. Determine the final energy of the system if its initial energy is 10 kJ.
4) Consider a hooded electric open burner in an area where the unit costs of electricity and natural gas are $0.07/kWh and $1.20/therm, respectively (Noting that 1 therm = 29.3 kWh) . The efficiency of open burners can be taken to be 73 percent for electric burners and 38 percent for gas burners.…
Compare wind, solar, and power generation systems with each other and write down their advantages and disadvantages among themselves in articles.
how does mechanical efficiency affect net power output calculation of a gas turbine power plant. does it only affect the compressor work. does it have an effect on the net work.
Chapter 2 Solutions
Thermodynamics: An Engineering Approach
Ch. 2.8 - What is the difference between the macroscopic and...Ch. 2.8 - What is total energy? Identify the different forms...Ch. 2.8 - List the forms of energy that contribute to the...Ch. 2.8 - How are heat, internal energy, and thermal energy...Ch. 2.8 - What is mechanical energy? How does it differ from...Ch. 2.8 - Portable electric heaters are commonly used to...Ch. 2.8 - Natural gas, which is mostly methane CH4, is a...Ch. 2.8 - Consider the falling of a rock off a cliff into...Ch. 2.8 - Electric power is to be generated by installing a...Ch. 2.8 - The specific kinetic energy of a moving mass is...
Ch. 2.8 - Determine the specific kinetic energy of a mass...Ch. 2.8 - Calculate the total potential energy, in Btu, of...Ch. 2.8 - Determine the specific potential energy, in kJ/kg,...Ch. 2.8 - An object whose mass is 100 kg is located 20 m...Ch. 2.8 - A water jet that leaves a nozzle at 60 m/s at a...Ch. 2.8 - Consider a river flowing toward a lake at an...Ch. 2.8 - At a certain location, wind is blowing steadily at...Ch. 2.8 - What is the caloric theory? When and why was it...Ch. 2.8 - In what forms can energy cross the boundaries of a...Ch. 2.8 - What is an adiabatic process? What is an adiabatic...Ch. 2.8 - When is the energy crossing the boundaries of a...Ch. 2.8 - Consider an automobile traveling at a constant...Ch. 2.8 - A room is heated by an iron that is left plugged...Ch. 2.8 - A room is heated as a result of solar radiation...Ch. 2.8 - A gas in a pistoncylinder device is compressed,...Ch. 2.8 - A small electrical motor produces 5 W of...Ch. 2.8 - A car is accelerated from rest to 85 km/h in 10 s....Ch. 2.8 - A construction crane lifts a prestressed concrete...Ch. 2.8 - Determine the torque applied to the shaft of a car...Ch. 2.8 - A spring whose spring constant is 200 lbf/in has...Ch. 2.8 - How much work, in kJ, can a spring whose spring...Ch. 2.8 - A ski lift has a one-way length of 1 km and a...Ch. 2.8 - The engine of a 1500-kg automobile has a power...Ch. 2.8 - A damaged 1200-kg car is being towed by a truck....Ch. 2.8 - As a spherical ammonia vapor bubble rises in...Ch. 2.8 - A steel rod of 0.5 cm diameter and 10 m length is...Ch. 2.8 - What are the different mechanisms for transferring...Ch. 2.8 - For a cycle, is the net work necessarily zero? For...Ch. 2.8 - On a hot summer day, a student turns his fan on...Ch. 2.8 - Water is being heated in a closed pan on top of a...Ch. 2.8 - An adiabatic closed system is accelerated from 0...Ch. 2.8 - A fan is to accelerate quiescent air to a velocity...Ch. 2.8 - A vertical pistoncylinder device contains water...Ch. 2.8 - At winter design conditions, a house is projected...Ch. 2.8 - A water pump increases the water pressure from 15...Ch. 2.8 - The lighting needs of a storage room are being met...Ch. 2.8 - A university campus has 200 classrooms and 400...Ch. 2.8 - Consider a room that is initially at the outdoor...Ch. 2.8 - An escalator in a shopping center is designed to...Ch. 2.8 - Consider a 2100-kg car cruising at constant speed...Ch. 2.8 - Prob. 51PCh. 2.8 - What is mechanical efficiency? What does a...Ch. 2.8 - How is the combined pumpmotor efficiency of a pump...Ch. 2.8 - Can the combined turbinegenerator efficiency be...Ch. 2.8 - Consider a 2.4-kW hooded electric open burner in...Ch. 2.8 - The steam requirements of a manufacturing facility...Ch. 2.8 - Reconsider Prob. 256E. Using appropriate software,...Ch. 2.8 - A 75-hp (shaft output) motor that has an...Ch. 2.8 - Prob. 59PCh. 2.8 - An exercise room has six weight-lifting machines...Ch. 2.8 - A room is cooled by circulating chilled water...Ch. 2.8 - The water in a large lake is to be used to...Ch. 2.8 - A 7-hp (shaft) pump is used to raise water to an...Ch. 2.8 - A geothermal pump is used to pump brine whose...Ch. 2.8 - At a certain location, wind is blowing steadily at...Ch. 2.8 - Reconsider Prob. 265. Using appropriate software,...Ch. 2.8 - Water is pumped from a lower reservoir to a higher...Ch. 2.8 - An 80-percent-efficient pump with a power input of...Ch. 2.8 - Water is pumped from a lake to a storage tank 15 m...Ch. 2.8 - Large wind turbines with a power capacity of 8 MW...Ch. 2.8 - A hydraulic turbine has 85 m of elevation...Ch. 2.8 - The water behind Hoover Dam in Nevada is 206 m...Ch. 2.8 - An oil pump is drawing 44 kW of electric power...Ch. 2.8 - A wind turbine is rotating at 15 rpm under steady...Ch. 2.8 - How does energy conversion affect the environment?...Ch. 2.8 - What is acid rain? Why is it called a rain? How do...Ch. 2.8 - Why is carbon monoxide a dangerous air pollutant?...Ch. 2.8 - What is the greenhouse effect? How does the excess...Ch. 2.8 - What is smog? What does it consist of? How does...Ch. 2.8 - Consider a household that uses 14,000 kWh of...Ch. 2.8 - When a hydrocarbon fuel is burned, almost all of...Ch. 2.8 - Prob. 82PCh. 2.8 - A typical car driven 20,000 km a year emits to the...Ch. 2.8 - Prob. 84PCh. 2.8 - What are the mechanisms of heat transfer?Ch. 2.8 - Which is a better heat conductor, diamond or...Ch. 2.8 - How does forced convection differ from natural...Ch. 2.8 - What is a blackbody? How do real bodies differ...Ch. 2.8 - Define emissivity and absorptivity. What is...Ch. 2.8 - Does any of the energy of the sun reach the earth...Ch. 2.8 - The inner and outer surfaces of a 5-m 6-m brick...Ch. 2.8 - The inner and outer surfaces of a 0.5-cm-thick 2-m...Ch. 2.8 - Reconsider Prob. 292. Using appropriate software,...Ch. 2.8 - Prob. 94PCh. 2.8 - Prob. 95PCh. 2.8 - Prob. 96PCh. 2.8 - Prob. 97PCh. 2.8 - For heat transfer purposes, a standing man can be...Ch. 2.8 - Prob. 99PCh. 2.8 - Prob. 100PCh. 2.8 - A 1000-W iron is left on the ironing board with...Ch. 2.8 - A 7-cm-external-diameter, 18-m-long hot-water pipe...Ch. 2.8 - A thin metal plate is insulated on the back and...Ch. 2.8 - Reconsider Prob. 2103. Using appropriate software,...Ch. 2.8 - The outer surface of a spacecraft in space has an...Ch. 2.8 - Prob. 106PCh. 2.8 - A hollow spherical iron container whose outer...Ch. 2.8 - Some engineers have developed a device that...Ch. 2.8 - Consider a classroom for 55 students and one...Ch. 2.8 - Consider a homeowner who is replacing his...Ch. 2.8 - Prob. 111RPCh. 2.8 - The U.S. Department of Energy estimates that...Ch. 2.8 - A typical household pays about 1200 a year on...Ch. 2.8 - Prob. 114RPCh. 2.8 - Prob. 115RPCh. 2.8 - Prob. 116RPCh. 2.8 - Consider a TV set that consumes 120 W of electric...Ch. 2.8 - Water is pumped from a 200-ft-deep well into a...Ch. 2.8 - Consider a vertical elevator whose cabin has a...Ch. 2.8 - Prob. 120RPCh. 2.8 - In a hydroelectric power plant, 65 m3/s of water...Ch. 2.8 - The demand for electric power is usually much...Ch. 2.8 - The pump of a water distribution system is powered...Ch. 2.8 - Prob. 124RPCh. 2.8 - A 2-kW electric resistance heater in a room is...Ch. 2.8 - Prob. 126FEPCh. 2.8 - A 75-hp compressor in a facility that operates at...Ch. 2.8 - On a hot summer day, the air in a well-sealed room...Ch. 2.8 - A fan is to accelerate quiescent air to a velocity...Ch. 2.8 - A 900-kg car cruising at a constant speed of 60...Ch. 2.8 - Prob. 131FEPCh. 2.8 - Prob. 132FEPCh. 2.8 - A 2-kW pump is used to pump kerosene ( = 0.820...Ch. 2.8 - Prob. 134FEPCh. 2.8 - Prob. 135FEPCh. 2.8 - Prob. 136FEPCh. 2.8 - Prob. 137FEPCh. 2.8 - Heat is transferred steadily through a...Ch. 2.8 - The roof of an electrically heated house is 7 m...
Additional Engineering Textbook Solutions
Find more solutions based on key concepts
19.8 Calculate the allowable tensile load for the connection shown. The plates are ASTM A36 steel and the weld ...
Applied Statics and Strength of Materials (6th Edition)
A number of common substances are
Some of these materials exhibit characteristics of both solid and fluid beha...
Fox and McDonald's Introduction to Fluid Mechanics
Comprehension Check 7-14
The power absorbed by a resistor can be given by P = I2R, where P is power in units of...
Thinking Like an Engineer: An Active Learning Approach (3rd Edition)
The solid steel shaft AC has a diameter of 25 mm and is supported by smooth bearings at D and E. It is coupled ...
Mechanics of Materials
3.3 It is known that a vertical force of 200 lb is required to remove the nail at C from the board. As the nail...
Vector Mechanics for Engineers: Statics, 11th Edition
What is the importance of modeling in engineering? How are the mathematical models for engineering processes pr...
Heat and Mass Transfer: Fundamentals and Applications
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 hydraulic turbine receives water from a reservoir at an elevation of 100 m above it. What is the minimum water flow in kg/s to produce a steady water power of 50MW?arrow_forwardA high reservoir holds water. Water travels from this reservoir down via a big conduit to a turbine and then down a second, similar-sized conduit to create electricity. The pressure is 172.4 kPa at a location in the conduit 89.5 m above the turbine and 89.6 kPa at a level 5 m below the turbine. The flow rate of water is 0.800 m3/s. The turbine's shaft produces 658 kW of power. The density of water is 1000 kg/m3. Calculate the friction loss in the turbine in J/kg if the turbine's efficiency in transferring the mechanical energy given up by the fluid to the turbine shaft is 89 percent (t = 0.89). It is worth noting that in the mechanical-energy-balance equation, Ws equals the output of the turbine's shaft multiplied by t. Note: Use the equation provided below MECHANICAL ENERGY BALANCES W s + gAz + F = AP F = AÛ • For frictionless processes in which no shaft work is performed, the mechanical energy balance is reduced to: ΔΡ Au² gAz = 0 Bernoulli Equationarrow_forwardA client is building a steam turbine power generation system that utilize a generator that requires a minimum input power of 1200 kW to be supplied by an existing steam turbine in their inventory. As the consulting engineer, you need to investigate whether the existing steam turbine is capable or not to supply the required output power for the generator. The details of the steam turbine are as follow: Inlet steam pressure : 10 MPa Inlet steam temperature :400°C Inlet mass flow rate :2 kg/s Outlet steam pressure : 50 kPa. Turbine isentropic efficiency : 0.80 For the analysis, assume that the turbine is adiabatic, and the kinetic energy change of the steam is negligible.arrow_forward
- Show that the power produced by a wind turbine is proportional to the cube of the wind velocity and to the square of the blade span diameter.arrow_forwardA mining company depleted more than half of its ore reserves and is no longer using all of its shaft infrastructure. It considers using one of the old shafts for pumped-storage hydro-electricity generation. This means that water will be pumped to the higher level, which is 1 000 m above the bottom level, at night when Eskom charges lower, off-peak, rates. The “higher level” will be changed into a dam (reservoir) by means of plugs that will be installed in some tunnels. The stored water has potential energy, which will be used to generate electricity for the mine at peak hours, when electricity is expensive. The pump that will be installed at the bottom of the column will also be used as a turbine for the generation of electricity The pump-as-turbine (PAT) must pump water to a height of 1 000 m through a column with an internal diameter (ID) of 345 mm. 3.1. Calculate the velocity of the water in the pipe if the quantity of water to be pumped is 220 litres per second (lps). 3.2.…arrow_forwardNo practical process, especially those involving heat, are 100% efficient. Assess the energy losses of a typical gas turbine system.arrow_forward
- In a power plant, water (density = 1000 kg/m³) is pumped from 80 kPa to 3 MPa. The pump has an isentropic efficiency of 0.85. Assuming that the temperature of the water remains the same, the specific work (in kJ/kg) supplied to the pump is %3Darrow_forwardFind the combined thermal efficiency of a 60,000 KW steam turbine generator at 50% load if the slope of the Willian's Line is at 3.4. Steam enters the turbine at an enthalpy of 3445 KJ/kg, leaves the turbine at 3138 KJ/kg and enters the boiler at 174.5 KJ/kg. Mass of steam at no-load is at 1680 kg/harrow_forwardOne method of meeting the extra electric power demand at peak periods is to pump some water from a large body of water (such as a lake) to a reservoir at a higher elevation at times of low demand and to generate electricity at times of high demand by letting this water run down and rotate a turbine (i.e., convert the electric energy to potential energy and then back to electric energy). For an energy storage capacity of 5 × 106 kWh, determine the minimum amount of water that needs to be stored at an average elevation (relative to the ground level) of 75 m.arrow_forward
- It takes 10 kW to keep the interior of a certain house at 20 degree C when the outside temperature is 0 degree C.This heat flow is usually obtained directly by burning gas or oil. Calculate the power required if the 10 kW heat flow-were supplied by operating a reversible engine with the house as the upper reservoir and the outside surroundings as the lower reservoir, so that the power were used only to perform work needed to operate the engine.arrow_forwardHow does a geothermal power plant generate electricity? Explain on the basis of heat transfer and energy transformation.arrow_forwardA gasoline engine is 30% efficient, which means it can transfer 30% of the energy heat provides the engine with useful success. If the engine consumes 0.8 L/h of gasoline with consumption index 3.5·104 kJ/L, find the amount of work done in kW and horsepower (hp)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