Solution Found!

Physics / College Physics 1 / Chapter 15 / Problem 25

College Physics | 1st Edition | ISBN: 9781938168000 | Authors: Paul Peter Urone, Roger Hinrichs

Change Question

Why do refrigerators, air conditioners, and heat pumps

Chapter 15, Problem 25

(choose chapter or problem)

Get Unlimited Answers

QUESTION:

Problem 25CQ

Why do refrigerators, air conditioners, and heat pumps operate most cost-effectively for cycles with a small difference between Th and Tc ? (Note that the temperatures of the cycle employed are crucial to its COP .)

Questions & Answers

QUESTION:

Problem 25CQ

Why do refrigerators, air conditioners, and heat pumps operate most cost-effectively for cycles with a small difference between Th and Tc ? (Note that the temperatures of the cycle employed are crucial to its COP .)

ANSWER:

Solution 25CQ

Step 1 of 3

The efficiency of a Carnot engine can be obtained as:

ηhp = 1- $\frac{Tc}{Th}$

This is same as the efficiency of a heat pump

The efficiency of the same can also be written as: ηhp = $\frac{W}{Qh}$

Hence when the temperature difference of the source and the sink increases, the work supplied must also increase, for the same heat to be supplied.

Hence for a given constant work input, (which is the general case) a heat pump works better at for a lower temperature difference.

Study Tools You Might Need

Chapter: 3 Problem: 84P

Introductory Chemistry 5
A lead fishing weight with a mass of 57 g absorbs 146 cal of heat. If its initial temperature is \(47\ ^{\circ}\mathrm{C}\), what is its final temperature? Equation Transcription: Text Transcription: 47

Chapter: 6 Problem: 96P

Principles of General Chemistry 2
Problem 96P Aqueous sulfurous acid (H2SO3) was made by dissolving 0.200 L of sulfur dioxide gas at 19C and 745 mmHg in water to yield 500.0 mL of solution. The acid solution required 10.0 mL of sodium hydroxide solution to reach the titration end point. What was the molarity of the sodium hydroxide s

Chapter: 9 Problem: 43AYU

Fundamentals of Statistics 4
Coefficient of Skewness Karl Pearson developed a measure that describes the skewness of a distribution, called the coefficient of skewness. The formula is The value of this measure generally lies between ?3 and +3. The closer the value lies to ?3, the more the distribution is skewed left. The

Chapter: Problem: 51

Physics for Scientists and Engineers: A Strategic Approach with Modern Physics 4
(II) In a certain region of space, the electric potential is given by V = y2 + 2.5xy - 3.5jcyz. Determine the electric field vector, E, in this region.

Chapter: Problem: 26

Mathematical Statistics and Data Analysis 3
Hampson and Walker also made measurements of the heats of sublimation of rhodium and iridium. Do the following calculations for each of the two given sets of data: a. Make a histogram. b. Make a stem-and-leaf plot. c. Make a boxplot. d. Plot the observations in the order of the experi

Chapter: 3 Problem: 1

Essentials of Understanding Psychology 11
Match each of the following organizational laws with its meaning: a. closure b. proximity c. similarity d. simplicity 1. Elements close together are grouped together. 2. Patterns are perceived in the most basic, direct manner possible. 3. Groupings are made in terms of complete figures. 4. Elements s

Chapter: 21 Problem: 6

Biology: The Dynamic Science 5
Which of the following represents an example of qualitative phenotypic variation? a. the lengths of peoples toes b. the body sizes of pigeons c. human ABO blood types d. the birth weights of humans e. the number of leaves on oak trees

Chapter: 12 Problem: 68

Biochemistry 9
What is a silent mutation? Why is the name silent mutation a bit of a misnomer?

Not The Solution You Need? Search for Your Answer Here:

×

Login

Login or Sign up for access to all of our study tools and educational content!

×

Register

Sign up for access to all content on our site!

Or login if you already have an account