Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
4th Edition
ISBN: 9780134110684
Author: Randall D. Knight (Professor Emeritus)
Publisher: PEARSON
bartleby

Videos

Textbook Question
Book Icon
Chapter 21, Problem 48EAP

48. A heat engine running backward is called a refrigerator if its

purpose is to extract heat from a cold reservoir. The same engine

running backward is called a heat pump if its purpose is to ex-

haust warm air into the hot reservoir. Heat pumps are widely used

for home heating. You can think of a heat pump as a refrigera-

tor that is cooling the already cold outdoors and, with its exhaust

heat QH, warming the indoors. Perhaps this seems a little silly, but

consider the following. Electricity can be directly used to heat a

home by passing an electric current through a heating coil. This

is a direct, 100% conversion of work to heat. That is, 15 kW of

electric power (generated by doing work at the rate of 15 kJ/s at

the power plant) produces heat energy inside the home at a rate of

15 kJ/s. Suppose that the neighbor's home has a heat pump with

a coefficient of performance of 5.0, a realistic value. Note that

"what you get" with a heat pump is heat delivered, QH, so a heat

pump's coefficient of performance is defined as K = QH/ Win.

a. How much electric power (in kW) does the heat pump use to

deliver 15 kJ/s of heat energy to the house?

b. An average price for electricity is about 40 MJ per dollar. A

furnace or heat pump will run typically 250 hours per month

during the winter. What does one month's heating cost in the

home with a 15 kW electric heater and in the home of the

neighbor who uses a heat pump?

Blurred answer
Students have asked these similar questions
suggest a reason ultrasound cleaning is better than cleaning by hand?
Checkpoint 4 The figure shows four orientations of an electric di- pole in an external electric field. Rank the orienta- tions according to (a) the magnitude of the torque on the dipole and (b) the potential energy of the di- pole, greatest first. (1) (2) E (4)
What is integrated science. What is fractional distillation What is simple distillation

Chapter 21 Solutions

Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)

Ch. 21 - Prob. 11CQCh. 21 - Prob. 1EAPCh. 21 - Prob. 2EAPCh. 21 - Prob. 3EAPCh. 21 - Prob. 4EAPCh. 21 - Prob. 5EAPCh. 21 - Prob. 6EAPCh. 21 - The power output of a car engine running at 2400...Ch. 21 - Prob. 8EAPCh. 21 - Prob. 9EAPCh. 21 - Prob. 10EAPCh. 21 - Prob. 11EAPCh. 21 - Prob. 12EAPCh. 21 - Prob. 13EAPCh. 21 - Prob. 14EAPCh. 21 - Prob. 15EAPCh. 21 - Prob. 16EAPCh. 21 - A heat engine uses a diatomic gas in a Brayton...Ch. 21 - At what pressure ratio does a Brayton cycle using...Ch. 21 - Prob. 19EAPCh. 21 - Prob. 20EAPCh. 21 - Prob. 21EAPCh. 21 - Prob. 22EAPCh. 21 - Prob. 23EAPCh. 21 - Prob. 24EAPCh. 21 - Prob. 25EAPCh. 21 - Prob. 26EAPCh. 21 - Prob. 27EAPCh. 21 - A Carnot engine whose hot-reservoir temperature is...Ch. 21 - Prob. 29EAPCh. 21 - A heat engine operating between energy reservoirs...Ch. 21 - Prob. 31EAPCh. 21 - A Carnot refrigerator operating between —20°C and...Ch. 21 - The coefficient of performance of a refrigerator...Ch. 21 - A Carnot heat engine with thermal efficiency 1/3...Ch. 21 - Prob. 35EAPCh. 21 - Prob. 36EAPCh. 21 - A heat engine with 50% of the Carnot efficiency...Ch. 21 - Prove that the work done in an adiabatic process i...Ch. 21 - Prob. 39EAPCh. 21 - Prob. 40EAPCh. 21 - An ideal refrigerator utilizes a Carnot cycle...Ch. 21 - Prob. 42EAPCh. 21 - There has long been an interest in using the vast...Ch. 21 - A Carnot heat engine operates between reservoirs...Ch. 21 - A Carnot engine operates between temperatures of...Ch. 21 - Prob. 46EAPCh. 21 - A Carnot heat engine and an ordinary refrigerator...Ch. 21 - 48. A heat engine running backward is called a...Ch. 21 - 49. A car's internal combustion engine can be...Ch. 21 - Prob. 50EAPCh. 21 - Prob. 51EAPCh. 21 - Prob. 52EAPCh. 21 - Prob. 53EAPCh. 21 - Prob. 54EAPCh. 21 - Prob. 55EAPCh. 21 - Prob. 56EAPCh. 21 - Prob. 57EAPCh. 21 - A heat engine using a monatomic gas follows the...Ch. 21 - Prob. 59EAPCh. 21 - Prob. 60EAPCh. 21 - Prob. 61EAPCh. 21 - Prob. 62EAPCh. 21 - Prob. 63EAPCh. 21 - Prob. 64EAPCh. 21 - Prob. 65EAPCh. 21 - Prob. 66EAPCh. 21 - Prob. 67EAPCh. 21 - Prob. 68EAPCh. 21 - Prob. 69EAPCh. 21 - Prob. 70EAPCh. 21 - A refrigerator using helium gas operates on the...Ch. 21 - Prob. 72EAPCh. 21 - The gasoline engine in your car can be modeled as...Ch. 21 - Prob. 74EAP
Knowledge Booster
Background pattern image
Physics
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
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Text book image
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Text book image
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Text book image
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College
Text book image
College Physics
Physics
ISBN:9781285737027
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
Text book image
Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
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