1. A steam power plant receives heat from a furnace at a rate of 280 GJI/h. Heat losses to the surrounding air from the steam as it passes through the pipes and other components are estimated to be about 8 GJ/h. If the waste heat is transferred to the cooling water at a rate of 145 GJ/h, determine (a) net power output and (b) the thermal efficiency of this power plant. show free-body diagram

1. A steam power plant receives heat from a furnace at a rate of 280 GJI/h. Heat losses to the surrounding air from the steam as it passes through the pipes and other components are estimated to be about 8 GJ/h. If the waste heat is transferred to the cooling water at a rate of 145 GJ/h, determine (a) net power output and (b) the thermal efficiency of this power plant. show free-body diagram

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter18: Heat Engines, Entropy, And The Second Law Of Thermodynamics

Section: Chapter Questions

Problem 13P

See similar textbooks

Similar questions

This problem compares the energy output and heat transfer to the environment by two different types of nuclear power stationsone with the normal efficiency of 34.0%, and another with an improved efficiency of 40.0%. Suppose both have the same heat transfer into the engine in one day. 2.501014J. (a) How much more electrical energy is produced by the more efficient power station? (b) How much less heat transfer occurs to the environment by the more efficient power station? (One type of more ef?cient nuclear power station, the gas—cooled reactor, has not been reliable enough to be economically feasible in spite of its greater eficiency.)
The energy exhaust from a certain coal-fired electric generating station is carried by cooling water into Lake Ontario. The water is warm from the viewpoint of living things in the lake. Some of them congregate around the outlet port and can impede the water flow. (a) Use the theory of heat engines to explain why this at lion can reduce the electric power output of the station, (b) An engineer says that the electric output is reduced because of higher back pressure on the turbine blades Comment on the accuracy of this statement.
What is the change in internal energy of a system which does 4.50105J of work while 3.00106J of heat transfer occurs into the system, and 8.00106J of heat transfer occurs to the environment?
(a) Calculate the rate of heat transfer by radiation from a car radiator at 110C into a 50.0C environment, if the radiator has an emissivity of 0.750 and a 1.20m2 surface area. (b) Is this a significant fraction of the heat transfer by an automobile engine? To answer this, assume a horsepower of 200 hp (1.5 kW) and the efficiency of automobile engines as 25%.
There is no change in the internal of an ideal gas undergoing an isothermal process since the internal energy depends only on the temperature. Is it therefore correct to say that an isothermal process is the same as an adiabatic process for an ideal gas? Explain your answer. `
(a) How much food energy will a man metabolize in the process of doing 35.0 kJ of work with an efficiency of 5.00%? (b) How much heal transfer occurs to the environment to keep his temperature constant? Explicitly show how you follow the steps in the Problem—Solving Strategy for thermodynamics found in Problem-Solving Strategies for Thermodynamics.
Practical steam engines utilize 450C steam, which is later exhausted at 270C. (a) What is the maximum eficiency that such a heat engine can have? (b) Since 270C steam is still quite hot, at second steam engine is sometimes operated using the exhaust of the first. What is the maximum eficiency of the second engine if its exhaust has a temperature of 150C ? (c) What is the overall eficiency of the two engines? (d) Show that this is the same eficiency as a single Carnot engine operating between 450C and 150C. Explicitly show how you follow the steps in the Problem-Solving Strategies for Thermodynamics.
You are working on a summer job at a company that designs non-traditional energy systems. The company is working on a proposed electric power plant that would make use of the temperature gradient in the ocean. The system includes a heat engine that would operate between 20.0C (surface-water temperature) and 5.00C (water temperature at a depth of about 1 km). (a) Your supervisor asks you to determine the maximum efficiency of such a system. (b) In addition, if the electric power output of the plant is 75.0 MW and it operates at the maximum theoretically possible efficiency, you must determine the rate at which energy is taken in from the warm reservoir. (c) From this information, if an electric bill for a typical home shows a use of 950 kWh per month, your supervisor wants to know how many homes can be provided with power from this energy system operating at its maximum efficiency. (d) As energy is drawn from the warm surface water to operate the engine, it is replaced by energy absorbed from sunlight on the surface. If the average intensity absorbed from sunlight is 650 W/m2 for 12 daylight hours on a clear day, you need to find the area of the ocean surface that is necessary for sunlight to replace the energy absorbed into the engine. (e) From this information, you need to determine if there is enough ocean surface on the Earth to use such engines to supply the electrical needs for all the homes associated with the Earths population. Assume the energy use for a home in part (c) is an average over the entire planet. (f) In view of your results in this problem, your supervisor has asked for your conclusion as to whether such a system is worthwhile to pursue. Note that the fuel (sunlight) is free.
Suppose a woman does 500 J of work and 9500 J of heat transfer occurs into the environment in the process. (a) What is the decrease in her internal energy, assuming no change in temperature or consumption of feed? (That is, there is no other energy transfer.) (b) What is her eficiency?
Can improved engineering and materials be employed in heat engines to reduce heat transfer into the environment? Can they eliminate heat transfer into the environment entirely?
(a) It is difficult to extinguish a fire on a crude oil tanker, because each liter of crude oil releases 2.80107J of energy when burned. To illustrate this difficulty, calculate the number of liters of water that must be expended to absorb the energy released by burning 1.00 L of crude oil, it the water has its temperature raised from 20.0C to 100C, it boils, and the resulting steam is raised to 300C. (b) Discuss additional complications caused by the fact that crude oil has a smaller density than water.
A system does 1.80108J of work while 7.50108J of heat transfer occurs to the environment. What is the change in internal energy of the system assuming no other changes (such as in temperature or by the addition of fuel)?