Essential University Physics (3rd Edition)
3rd Edition
ISBN: 9780134202709
Author: Richard Wolfson
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 19, Problem 37P
You operate a store that’s heated by an oil furnace supplying 30 kWh of heat from each gallon of oil. You’re considering switching to a heat-pump system. Oil costs $1.75/gallon, and electricity costs 16.5ȼ/kWh. What’s the minimum heat-pump COP that will reduce your heating costs?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Many decisions are made on the basis of the payback period: the time it will take through savings to equal the capital cost of an investment. Acceptable payback times depend upon the business or philosophy one has. (For some industries, a payback period is as small as two years.) Suppose you wish to install the extra insulation. If energy cost $1.00 per million joules and the insulation was $4.00 per square meter, then calculate the simple payback time. Take the average for the 120 day heating season to be 15.0C.
A hot water heater in a residential home runs for an average of 3.2 hours per day with a heat energy input of 3.7 kW. What would be the annual cost for hot water in this home using a gas hot water heater if the cost of natural gas is $0.33/m3? The gas water heater can get 23 MJ of energy from 1 m3 of natural gas. [round your final answer to zero decimal places]?
A certain coal-fired power plant has a rated power capacity of P = 850 MW. The output of this plant is W = 0.26QH, where QH is the energy input as heat from the hot reservoir.
a. If the power plant operates for a full day at its rated capacity, how much energy QH in MJ is needed?
b. If, on average, one ton of coal contains Q = 25 GJ of energy, how many tons nH of coal would the plant need to operate for a day at its rated capacity?
c. How many tons nC of this coal is exhausted as wasted heat to QC in a single day?
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
Additional Science Textbook Solutions
Find more solutions based on key concepts
A student is attempting to move a 30-kg mini-fridge into her dorm room. During a moment of Inattention, the min...
University Physics Volume 1
24.(I) A light plane must reach a speed of 35 m/s for takeoff. How long a runway is needed if the (constant) ac...
Physics: Principles with Applications
For a solid, we also define the linear thermal expansion coefficient, a, as the fractional increase in length p...
An Introduction to Thermal Physics
The diagrams at right show two identical gliders that move to the right without friction. The hands exert ident...
Tutorials in Introductory Physics
8.7 • Force of a Golf Swing. A 0.0450-kg golf ball initially at rest is given a speed of 25.0 m/s when a club s...
University Physics with Modern Physics (14th Edition)
An unknown capacitor C is connected in series with a 3.0-F capacitor; this pair is placed in parallel with a 1....
Essential University Physics: Volume 2 (3rd Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- A 361-W heat pump operates between the ground, whose temperature is 6.2, and the interior of a house at 20.1. What is the theoretical maximum amount of heat per hour that the heat pump can supply to the house? Express your answer in MJ, to at least one digit after the decimal point.arrow_forward250 students sit in an auditorium listening to a physics lecture. Because they are thinking hard, each is using 125 W of metabolic power, slightly more than they would use at rest. An air conditioner with a COP of 5.0 is being used to keep the room at a constant temperature. What minimum electric powermust be used to operate the air conditioner?arrow_forwardA heat engine has a solar collector receiving 600 Btu/h per square foot, inside which a transfer medium is heated to 800 R. The collected energy powers a heat engine that rejects heat at 100 F. If the heat engine should deliver 8500 Btu/h, what is the minimum size (area) of the solar collector?arrow_forward
- How much energy would you consume daily if you kept 3 lightbulbs of 25 watts on all day long?.arrow_forwardAn electric refrigerator rated 400 W operates 8 hour/day. What is the cost of the energy to operate it for 30 days at Rs 3.00 per kW h?arrow_forwardA heat engine extracts 59 kJkJ from the hot reservoir and exhausts 32 kJkJ into the cold reservoir. What is the work done? What is the efficiency?arrow_forward
- The average electricity consumption of a house in Gainesville is known to be 1,036 kWh in a month (One month = 30 days). They would like to install solar panels of 30 % efficiency to generate this electricity. Given that the average solar power density in Gainesville is 5.47 kWh/m2/day, how much surface area must the panels occupy? Calculate the result in m² but do not write the unit. Round off you E swer to a whole number (zero decimal place.)arrow_forwardSuppose you have a 1000Wmicrowave that you need to run for 5minto heat up your dinner.1. How much energy does it take to heat up your dinner?2. At$0.12/kWhr, how long much does it cost to warm up your dinner?arrow_forward3.5x10^7 J of heat transfers into an engine. If 2.1x10^7 J of work is performed what is the efficiency of the engine? How much heat is lost to the environment?arrow_forward
- A power plant has a power output of 1285 MWand operates with an efficiency of 32.4 percent. Excess energy is carried away as heatfrom the plant to a nearby river that has aflow rate of 1.1 × 106kg/s.How much energy is transferred as heat tothe river each second?Answer in units of J/s.arrow_forwardA typical coal-fired power plant burns 340 metric tons of coal every hour to generate 2.5 × 106 MJ of energy. One metric ton has a mass of 1000 kg and a metric ton of coal has a volume of 1.5 m^3. The heat of combustion is 28 MJ/kg. What is the power plant’s efficiency?arrow_forwardA heat engine receives heat in the amount of Qh= 525 kJ from a high temperature thermal reservoir and delivers W, net= 360 kJ of work per cycle. Write an expression for the efficiency of the engine. What is this efficiency? n = Write an expression for the amount of energy required to be rejected into the low temperature reservoir. How much energy, in kilojoules, is rejected into the low temperature resevoir?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
The Second Law of Thermodynamics: Heat Flow, Entropy, and Microstates; Author: Professor Dave Explains;https://www.youtube.com/watch?v=MrwW4w2nAMc;License: Standard YouTube License, CC-BY