THERMODYNAMICS LLF W/ CONNECT ACCESS
THERMODYNAMICS LLF W/ CONNECT ACCESS
9th Edition
ISBN: 9781264446889
Author: CENGEL
Publisher: MCG
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 3.8, Problem 30P

A piston–cylinder device contains 0.85 kg of refrigerant-134a at −10°C. The piston that is free to move has a mass of 12 kg and a diameter of 25 cm. The local atmospheric pressure is 88 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 15°C. Determine (a) the final pressure, (b) the change in the volume of the cylinder, and (c) the change in the enthalpy of the refrigerant-134a.

FIGURE P3–30

Chapter 3.8, Problem 30P, A pistoncylinder device contains 0.85 kg of refrigerant-134a at 10C. The piston that is free to move

(a)

Expert Solution
Check Mark
To determine

The final pressure of the refrigerant R-134a.

Answer to Problem 30P

The final pressure of the refrigerant R-134a is 90.4kPa_

Explanation of Solution

The final pressure is equal to the initial pressure of the refrigerant R-134a.

P2=P1=Patm+mpg(πD24) (I)

Here, atmospheric pressure is Patm, mass of piston-cylinder device is mp, acceleration due to gravity is g, and diameter of a piston is D.

Conclusion:

Substitute 88 kPa for Patm, 12 kg for mp, 9.81m/s2 for g, and 25 cm for D in Equation (I).

P2=88kPa+(12kg)(9.81m/s2)(π(25cm)24)=88kPa+(12kg)(9.81m/s2)(π(25cm)24)(1kN1000kgm/s2)=90.4kPa

Thus, the final pressure of the refrigerant R-134a is 90.4kPa_.

(b)

Expert Solution
Check Mark
To determine

The change in the volume of the cylinder.

Answer to Problem 30P

The change in the volume of the cylinder is 0.02142m3_.

Explanation of Solution

Convert the unit of initial pressure from kPa to MPa.

P1=90.4kPa=90.4kPa(1MPa1000kPa)=0.0904MPa

Write the formula of interpolation method of two variables at 10°C.

y2=(x2x1)(y3y1)(x3x1)+y1 (II)

Here, the variables denote by x and y are pressure and specific volume.

Calculate the initial volume of cylinder.

ν1=mv1 (III)

Here, the initial state specific volume is v1.

Calculate the final volume of cylinder.

ν2=mv2 (IV)

Here, the final state specific volume is v2.

Calculate the change in the volume of cylinder.

Δν=ν2ν1 (V)

Conclusion:

Refer to Table A-13, obtain the values of below variables as in Table (I) at 10°C.

Pressure, MPa (x)Specific volume, m3/kg (y)
0.060.35048
0.0904?
0.100.20743

Substitute 0.06 for x1, 0.0904 for x2, 0.10 for x3, 0.35048 for y1, and 0.20743 for y3 in Equation (II).

y2=(0.09040.06)(0.207430.35048)(0.100.06)+0.35048=0.2418

Thus, the specific volume of refrigerant R-134a at the initial state of 90.4 kPa and 10°C is 0.2418m3/kg.

Refer to Table A-13, obtain the values of below variables as in Table (II) at 10°C.

Pressure, MPa (x)Enthalpy, kJ/kg (y)
0.06248.60
0.0904?
0.10247.51

Substitute 0.06 for x1, 0.0904 for x2, 0.10 for x3, 248.60 for y1, and 247.51 for y3 in Equation (II).

y2=(0.09040.06)(247.51248.60)(0.100.06)+248.60=247.77

Thus, the enthalpy of refrigerant R-134a at the initial state of 90.4 kPa and 10°C is 247.77kJ/kg.

Apply spreadsheet and solve the final state specific volume at 15°C and 0.0904 MPa using interpolation method.

Refer to Table A-13, obtain the values of below variables as in Table (III) at 15°C and 0.06 MPa.

Temperature, °C (x)Specific volume, m3/kg (y)
100.37893
15?
200.39302

Substitute 10 for x1, 15 for x2, 20 for x3, 0.37893 for y1, and 0.39302 for y3 in Equation (II).

y2=(1510)(0.393020.37893)(2010)+0.37893=0.386

Similarly, solve final state specific volume at 15°C and 0.10 MPa using interpolation method as 0.2294m3/kg.

Now use interpolation method again to solve the final state specific volume at 15°C. Refer to Table A-13, obtain the values of below variables as in Table (IV) at 15°C and 0.0904 MPa.

Pressure, MPa (x)Specific volume, m3/kg (y)
0.060.386
0.0904?
0.100.2294

Substitute 0.06 for x1, 0.0904 for x2, 0.10 for x3, 0.386 for y1, and 0.2294 for y3 in Equation (II).

y2=(0.09040.06)(0.22940.386)(0.100.06)+0.386=0.267

Thus, the final state specific volume at 15°C and 90.4 kPa is 0.267m3/kg.

Apply the above steps to calculate the enthalpy at 15°C and 90.4 kPa using interpolation method as 268.19kJ/kg.

Substitute 0.85 kg for m and 0.2418m3/kg for v1 in Equation (III).

ν1=0.85kg(0.2418m3/kg)=0.20553m3

Substitute 0.85 kg for m and 0.267m3/kg for ν2 in Equation (IV).

ν2=0.85kg(0.267m3/kg)=0.22695m3

Substitute 0.22695m3 for ν2 and 0.20553m3 for ν1 in Equation (V).

Δν=0.22695m30.20553m3=0.02142m3

Thus, the change in the volume of the cylinder is 0.02142m3_.

(c)

Expert Solution
Check Mark
To determine

The change in the enthalpy of the refrigerant R-134a.

Answer to Problem 30P

The change in the enthalpy of the refrigerant R-134a is 17.35kJ/kg_.

Explanation of Solution

Calculate the total enthalpy change of refrigerant R-134a.

ΔH=m(h2h1) (VI)

Here, enthalpy at initial state and final state are h1andh2 respectively.

Conclusion:

Substitute 0.85 kg for m, 247.77kJ/kg for h1 and 268.19kJ/kg for h2 in equation (VI).

ΔH=0.85kg(268.19kJ/kg247.77kJ/kg)=17.35kJ/kg

Thus, the change in the enthalpy of the refrigerant R-134a is 17.35kJ/kg_.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
A piston–cylinder device contains 0.85 kg of refrigerant- 134a at 210ºC. The piston that is free to move has a mass of 12 kg and a diameter of 25 cm. The local atmospheric pressure is 88 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 15ºC. Determine: (a) the final pressure,(b) the change in the volume of the cylinder, and (c) the change in the enthalpy of the refrigerant-134a.
A piston-cylinder device contains 0.850 kg of refrigerant-134a at –10.0°C. The piston that is free to move and has a mass of 12.0 kg and a diameter of 25.0 cm. The local atmospheric pressure is 88.0 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 15.0°C. Determine (a) the final pressure, (b) the change in the volume of the cylinder, and (c) the change in the enthalpy of the refrigerant- 134a. Assume the following: va-10°C = 0.2302 m³/kg, va-15°C = 0.2544 m³/kg, ha-10°C = 247.22 kJ/kg, h@15°C = 268.18 kJ/kg
3. A piston-cylinder device contains .85 kg of refrigerant-R134a at -10 °C. The piston that is free to move has a mass of 12 kg and a diameter of 25 cm. The local atmospheric pressure is 88 kPa. Now, heat is transferred to refrigerant-134a until the temperature is 15°C. Determine (a) the final pressure, (b) the change in the volume of the cylinder, and (c) the change in the enthalpy of the refrigerant-134a. R-134a 0.85 kg -10°C

Chapter 3 Solutions

THERMODYNAMICS LLF W/ CONNECT ACCESS

Ch. 3.8 - Does the amount of heat absorbed as 1 kg of...Ch. 3.8 - Does the reference point selected for the...Ch. 3.8 - What is the physical significance of hfg? Can it...Ch. 3.8 - Does hfg change with pressure? How?Ch. 3.8 - Is it true that it takes more energy to vaporize 1...Ch. 3.8 - Which process requires more energy: completely...Ch. 3.8 - In what kind of pot will a given volume of water...Ch. 3.8 - It is well known that warm air in a cooler...Ch. 3.8 - In the absence of compressed liquid tables, how is...Ch. 3.8 - A perfectly fitting pot and its lid often stick...Ch. 3.8 - Complete this table for H2O:Ch. 3.8 - Complete this table for H2O:Ch. 3.8 - Complete this table for H2O:Ch. 3.8 - Complete this table for H2O:Ch. 3.8 - Complete this table for refrigerant-134a:Ch. 3.8 - Complete this table for refrigerant-134a:Ch. 3.8 - A 1.8-m3 rigid tank contains steam at 220C....Ch. 3.8 - One pound-mass of water fills a container whose...Ch. 3.8 - A pistoncylinder device contains 0.85 kg of...Ch. 3.8 - 10 kg of R-134a fill a 1.115-m3 rigid container at...Ch. 3.8 - What is the specific internal energy of water at...Ch. 3.8 - What is the specific volume of water at 5 MPa and...Ch. 3.8 - What is the specific volume of R-134a at 20C and...Ch. 3.8 - Refrigerant-134a at 200 kPa and 25C flows through...Ch. 3.8 - One kilogram of R-134a fills a 0.14-m3 weighted...Ch. 3.8 - One kilogram of water vapor at 200 kPa fills the...Ch. 3.8 - The temperature in a pressure cooker during...Ch. 3.8 - How much error would one expect in determining the...Ch. 3.8 - Water is to be boiled at sea level in a...Ch. 3.8 - Repeat Prob. 340 for a location at an elevation of...Ch. 3.8 - 10 kg of R-134a at 300 kPa fills a rigid container...Ch. 3.8 - 100 kg of R-134a at 200 kPa are contained in a...Ch. 3.8 - Water initially at 200 kPa and 300C is contained...Ch. 3.8 - Saturated steam coming off the turbine of a steam...Ch. 3.8 - A person cooks a meal in a 30-cm-diameter pot that...Ch. 3.8 - Water is boiled at 1 atm pressure in a...Ch. 3.8 - Repeat Prob. 347 for a location at 2000-m...Ch. 3.8 - Prob. 49PCh. 3.8 - A rigid tank with a volume of 1.8 m3 contains 40...Ch. 3.8 - A pistoncylinder device contains 0.005 m3 of...Ch. 3.8 - A 5-ft3 rigid tank contains a saturated mixture of...Ch. 3.8 - Superheated water vapor at 180 psia and 500F is...Ch. 3.8 - One kilogram of water fills a 150-L rigid...Ch. 3.8 - 10 kg of R-134a fill a 0.7-m3 weighted...Ch. 3.8 - A pistoncylinder device contains 0.6 kg of steam...Ch. 3.8 - A pistoncylinder device initially contains 1.4 kg...Ch. 3.8 - Water is being heated in a vertical pistoncylinder...Ch. 3.8 - A rigid tank initially contains 1.4 kg saturated...Ch. 3.8 - A pistoncylinder device initially contains 50 L of...Ch. 3.8 - The spring-loaded pistoncylinder device shown in...Ch. 3.8 - A pistoncylinder device initially contains steam...Ch. 3.8 - Under what conditions is the ideal-gas assumption...Ch. 3.8 - What is the difference between mass and molar...Ch. 3.8 - Propane and methane are commonly used for heating...Ch. 3.8 - What is the specific volume of oxygen at 25 psia...Ch. 3.8 - A 100-L container is filled with 1 kg of air at a...Ch. 3.8 - A mass of 1 lbm of argon is maintained at 200 psia...Ch. 3.8 - A 400-L rigid tank contains 5 kg of air at 25C....Ch. 3.8 - The pressure gage on a 2.5-m3 oxygen tank reads...Ch. 3.8 - A spherical balloon with a diameter of 9 m is...Ch. 3.8 - Reconsider Prob. 373. Using appropriate software,...Ch. 3.8 - A 1-m3 tank containing air at 10C and 350 kPa is...Ch. 3.8 - A mass of 10 g of oxygen fill a weighted...Ch. 3.8 - A mass of 0.1 kg of helium fills a 0.2 m3 rigid...Ch. 3.8 - A rigid tank whose volume is unknown is divided...Ch. 3.8 - A rigid tank contains 20 lbm of air at 20 psia and...Ch. 3.8 - In an informative article in a magazine it is...Ch. 3.8 - What is the physical significance of the...Ch. 3.8 - Determine the specific volume of refrigerant-134a...Ch. 3.8 - Refrigerant-134a at 400 psia has a specific volume...Ch. 3.8 - Determine the specific volume of superheated water...Ch. 3.8 - Determine the specific volume of superheated water...Ch. 3.8 - Determine the specific volume of nitrogen gas at...Ch. 3.8 - Prob. 88PCh. 3.8 - Carbon dioxide gas enters a pipe at 3 MPa and 500...Ch. 3.8 - Prob. 90PCh. 3.8 - A 0.016773-m3 tank contains 1 kg of...Ch. 3.8 - Prob. 92PCh. 3.8 - What is the percentage of error involved in...Ch. 3.8 - What is the physical significance of the two...Ch. 3.8 - Refrigerant-134a at 400 psia has a specific volume...Ch. 3.8 - A 3.27-m3 tank contains 100 kg of nitrogen at 175...Ch. 3.8 - Nitrogen at 150 K has a specific volume of...Ch. 3.8 - A 1-m3 tank contains 2.841 kg of steam at 0.6 MPa....Ch. 3.8 - Prob. 103PCh. 3.8 - Prob. 104PCh. 3.8 - On a certain day, the temperature and relative...Ch. 3.8 - Prob. 106PCh. 3.8 - Consider two rooms that are identical except that...Ch. 3.8 - A thermos bottle is half-filled with water and is...Ch. 3.8 - Complete the blank cells in the following table of...Ch. 3.8 - Complete the blank cells in the following table of...Ch. 3.8 - Prob. 111RPCh. 3.8 - Prob. 112RPCh. 3.8 - The gage pressure of an automobile tire is...Ch. 3.8 - A tank contains argon at 600C and 200 kPa gage....Ch. 3.8 - The combustion in a gasoline engine may be...Ch. 3.8 - Prob. 116RPCh. 3.8 - Prob. 117RPCh. 3.8 - A rigid tank with a volume of 0.117 m3 contains 1...Ch. 3.8 - A 9-m3 tank contains nitrogen at 17C and 600 kPa....Ch. 3.8 - A 10-kg mass of superheated refrigerant-134a at...Ch. 3.8 - A 4-L rigid tank contains 2 kg of saturated...Ch. 3.8 - Prob. 123RPCh. 3.8 - A tank whose volume is unknown is divided into two...Ch. 3.8 - Prob. 125RPCh. 3.8 - A tank contains helium at 37C and 140 kPa gage....Ch. 3.8 - Prob. 127RPCh. 3.8 - On the property diagrams indicated below, sketch...Ch. 3.8 - Ethane at 10 MPa and 100C is heated at constant...Ch. 3.8 - Steam at 400C has a specific volume of 0.02 m3/kg....Ch. 3.8 - Consider an 18-m-diameter hot-air balloon that,...Ch. 3.8 - Prob. 135FEPCh. 3.8 - A 3-m3 rigid vessel contains steam at 2 MPa and...Ch. 3.8 - Prob. 137FEPCh. 3.8 - Water is boiled at 1 atm pressure in a coffeemaker...Ch. 3.8 - Prob. 139FEPCh. 3.8 - Water is boiled in a pan on a stove at sea level....Ch. 3.8 - A rigid tank contains 2 kg of an ideal gas at 4...Ch. 3.8 - The pressure of an automobile tire is measured to...Ch. 3.8 - Consider a sealed can that is filled with...
Knowledge Booster
Background pattern image
Mechanical Engineering
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Text book image
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Text book image
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Text book image
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Text book image
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Text book image
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
Thermodynamics - Chapter 3 - Pure substances; Author: Engineering Deciphered;https://www.youtube.com/watch?v=bTMQtj13yu8;License: Standard YouTube License, CC-BY