Question
Asked Oct 6, 2019
1 views

This problem is (6.21) from a book  "Thermodynamics and Statistical Mechanics An Integrated Approach by M. Scott Shell"

6.21. A refrigerator is the opposite of a heat engine: it uses work supplied from the
environment to move heat from a cold to a hot reservoir, effectively keeping
the former at a lower temperature. The coefficient of performance measures the
help_outline

Image Transcriptionclose

6.21. A refrigerator is the opposite of a heat engine: it uses work supplied from the environment to move heat from a cold to a hot reservoir, effectively keeping the former at a lower temperature. The coefficient of performance measures the

fullscreen
efficiency of this process, defined by o
maximum value of o that is possible according to the second law.
Qcl/W. Find an
expression for the
help_outline

Image Transcriptionclose

efficiency of this process, defined by o maximum value of o that is possible according to the second law. Qcl/W. Find an expression for the

fullscreen
check_circle

Expert Answer

Step 1

Efficiency of refrigerator is measured by coefficient of performance

COP  of a refrigerator is written as:

Where QC = Heat removed from the cold reservoir

             W = work required to lift the liquid

help_outline

Image Transcriptionclose

1Qcl W

fullscreen
Step 2

From the second law of thermodynamic it is not possible to transfer heat from lower temperature to higher temperature.

From the first law of thermodynamic work required  W is given as:

Where Qh is heat transfer to the hot reservoir

              Qc is heat transfer from the cold reservoir

help_outline

Image Transcriptionclose

W-Qh-Qc

fullscreen
Step 3

Carnot engine is the most efficient engine. It is an ideal engine.

From the Carnot cycle it can be written as

Where Th = source temperatu...

help_outline

Image Transcriptionclose

Qe T

fullscreen

Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Solutions are written by subject experts who are available 24/7. Questions are typically answered within 1 hour.*

See Solution
*Response times may vary by subject and question.
Tagged in

Engineering

Chemical Engineering

Thermodynamics

Related Chemical Engineering Q&A

Find answers to questions asked by student like you
Show more Q&A
add
question_answer

Q: Water in a tank is pressurized by air while a gauge connected to the tank reads a pressure of 90 kPa...

A: Using Pascal’s law and Hydrostatic law of pressure the differential height h2 is calculated.Hydrosta...

question_answer

Q: This problem is (6.20) from a book  "Thermodynamics and Statistical Mechanics An Integrated Approach...

A: Note: Since we only answer up to 3 sub-parts, we’ll answer the first 3. Please resubmit the question...

question_answer

Q: A horizontal steam pipe has an outer diameter of 8.9 cm and passes through a large room whose walls ...

A: The formula used to calculate the heat loss by radiation is written below:

question_answer

Q: 5.20. Multistage stripper. A stripper at 50 psia with three equilibrium stages strips 1,000 kmol/h o...

A: The process diagram of given process is given below

question_answer

Q: 6.19 Consider the following cascade connection of isothermal reactors. A first-order reaction A Bocc...

A: Since questions has many parts, we are only answering first three parts. Part (a)For tank A,Mass bal...

question_answer

Q: You have been assigned to collect thermodynamic data for a new dialysis liquid your company is about...

A: The following information is given in the problem:Liquid mass flow rate through pipe  = 228 g/min   ...

question_answer

Q:

A: Part (a)Let the mass of the fermenter products be mF kg which is fed to the distiller to produce mD ...

question_answer

Q: Cyclohexanol is a highly desired chemical precursor for the production of nylon (billions of kilogra...

A: Part (a):Since all the derivatives are zero and y=u=0 at the nominal steady state, Hence taking lapl...

question_answer

Q: The inner pipe of a double-pipe heat exchanger has an OD of 1.9 in. and contains 36 rectangular fins...

A: Note: Since we only answer up to 3 sub-parts, we’ll answer the first 3. Please resubmit the question...