Essential University Physics (3rd Edition)
3rd Edition
ISBN: 9780134202709
Author: Richard Wolfson
Publisher: PEARSON
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Textbook Question
Chapter 19, Problem 39P
A heat pump extracts energy from groundwater at 10°C and transfers it to water at 70°C to heat a building. Find (a) its COP and (b) its electric power consumption if it supplies heat at the rate of 20 kW. (c) Compare the pump’s hourly operating cost with that of an oil furnace if electricity costs 15.5¢/kWh and oil costs $3.60/gallon and releases about 30 kWh/gal when burned.
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Chapter 19 Solutions
Essential University Physics (3rd Edition)
Ch. 19.1 - Which of these processes is irreversible? (a)...Ch. 19.2 - The low temperature for a practical heat engine is...Ch. 19.3 - A clever engineer decides to increase the...Ch. 19.4 - In each of the following processes, does the...Ch. 19 - Could you cool the kitchen by leaving the...Ch. 19 - Prob. 2FTDCh. 19 - Should a car get better mileage in the summer or...Ch. 19 - Prob. 4FTDCh. 19 - Name some irreversible processes that occur in a...Ch. 19 - Your power company claims that electric heat is...
Ch. 19 - A hydroelectric power plant, using the energy of...Ch. 19 - A heat-pump manufacturer claims the device will...Ch. 19 - Prob. 9FTDCh. 19 - The heat Q added during adiabatic free expansion...Ch. 19 - Energy is conserved, so why cant we recycle it as...Ch. 19 - Why doesnt the evolution of human civilization...Ch. 19 - What are the efficiencies of reversible heat...Ch. 19 - A cosmic heat engine might operate between the...Ch. 19 - A reversible Carnot engine operating between...Ch. 19 - A Carnot engine absorbs 900 J of heat each cycle...Ch. 19 - Find the COP of a reversible refrigerator...Ch. 19 - Prob. 18ECh. 19 - The human body can be 25% efficient at converting...Ch. 19 - Calculate the entropy change associated with...Ch. 19 - You metabolize a 650-kcal burger at your 37C body...Ch. 19 - You heat 250 g of water from 10C to 95C. By how...Ch. 19 - Melting a block of lead already at its melting...Ch. 19 - How much energy becomes unavailable for work in an...Ch. 19 - Prob. 25ECh. 19 - A Carnot engine extracts 745 J from a 592-K...Ch. 19 - The maximum steam temperature in a nuclear power...Ch. 19 - Youre engineering an energy-efficient house that...Ch. 19 - A power plants electrical output is 750 MW....Ch. 19 - A power plant extracts energy from steam at 280C...Ch. 19 - The electric power output of all the thermal...Ch. 19 - Consider a Carnot engine operating between...Ch. 19 - An industrial freezer operates between 0C and 32C,...Ch. 19 - Use appropriate energy-flow diagrams to analyze...Ch. 19 - Prob. 35PCh. 19 - A refrigerator maintains an interior temperature...Ch. 19 - You operate a store thats heated by an oil furnace...Ch. 19 - Use energy-flow diagrams to show that the...Ch. 19 - A heat pump extracts energy from groundwater at...Ch. 19 - A reversible engine contains 0.350 mol of ideal...Ch. 19 - (a) Determine the efficiency for the cycle shown...Ch. 19 - A 0.20-mol sample of an ideal gas goes through the...Ch. 19 - A shallow pond contains 94 Mg of water. In winter,...Ch. 19 - Estimate the rate of entropy increase associated...Ch. 19 - The temperature of n moles of ideal gas is changed...Ch. 19 - The temperature of n moles of ideal gas is changed...Ch. 19 - A 6.36-mol sample of ideal diatomic gas is at 1.00...Ch. 19 - A 250-g sample of water at 80C is mixed with 250 g...Ch. 19 - An ideal gas undergoes a process that takes it...Ch. 19 - In an adiabatic free expansion, 6.36 mol of ideal...Ch. 19 - Find the entropy change when a 2.4-kg aluminum pan...Ch. 19 - An engine with mechanical power output 8.5 kW...Ch. 19 - Find the change in entropy as 2.00 kg of H2O at...Ch. 19 - Gasoline engines operate approximately on the Otto...Ch. 19 - The compression ratio r of an engine is the ratio...Ch. 19 - In a diesel cycle, gas at volume V1 and pressure...Ch. 19 - (a) Show that the heal flowing into the diesel...Ch. 19 - Youre considering buying a car that comes in...Ch. 19 - The 54-M W wood-fired McNeil Generating Station in...Ch. 19 - A 500-g copper block at 80C is dropped into 1.0 kg...Ch. 19 - An objects heat capacity is inversely proportional...Ch. 19 - A Carnot engine extracts heat from a block of mass...Ch. 19 - In an alternative universe, youve got the...Ch. 19 - Youre the environmental protection officer for a...Ch. 19 - Find an expression for the entropy gain when hot...Ch. 19 - Problem 74 of Chapter 16 provided an approximate...Ch. 19 - The molar specific heat at constant pressure for a...Ch. 19 - Prob. 68PCh. 19 - Energy-efficiency specialists measure the heat Qh...Ch. 19 - Refrigerators remain among the greatest consumers...Ch. 19 - The refrigerators COP is a. 13. b. 2. c. 3. d. 4.Ch. 19 - The fuel energy consumed at the power plant to run...Ch. 19 - Prob. 73PP
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