# ME103: Thermodynamics

Unit 4: First Law of Thermodynamics   Thermodynamics operates according to two main laws.  In this unit, we will take an in-depth look at the first of these, which states that energy is conserved.  In other words, energy can be altered and transformed, but it can never be created or destroyed.  For example, an apple contains a certain amount of potential energy.  If you eat the apple, you digest it and, after a series of processes, convert the apple’s potential energy into the kinetic energy that powers you when you walk around.  The apple’s potential energy was not lost; it was merely changed into another form.

The first law sets an upper limit on the interconversion of different forms of energy and work.  It is often paraphrased as “You can’t win;” that is, you “can’t get something for nothing.”  Understanding this concept is as fundamental to science and engineering work as balancing an account is to finance.

This unit will take you approximately 34 hours to complete.

☐    Subunit 4.1: 4 hours

☐    Subunit 4.2: 9 hours

☐    Subunit 4.2.1: 3 hours

☐    Subunit 4.2.2: 3 hours

☐    Subunit 4.2.3: 3 hours

☐    Subunit 4.3: 18 hours

☐    Subunit 4.3.1: 3 hours

☐    Subunit 4.3.2: 3 hours

☐    Subunit 4.3.3: 3 hours

☐    Subunit 4.3.4: 3 hours

☐    Subunit 4.3.5: 3 hours

☐    Subunit 4.3.6: 3 hours

☐    Subunit 4.4: 3 hours

Unit4 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- State and illustrate the first law of thermodynamics for closed systems. - State and illustrate the first law of thermodynamics for open systems. - Formulate energy conservation equations for systems. - Apply the first law of thermodynamics to study steady-state, steady-flow (SSSF) processes. - Derive mass and energy conservation equations for several basic SSSF processes, including nozzles, diffusers, throttles, pumps, fans, blowers, turbines, compressors, heat exchangers, and mixing chambers.

4.1 The First Law for Closed Systems   - Reading: North Carolina State University: Professor Boles' Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” Link: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” (PDF)

Instructions: Please click on “Study Guide for Chapter 4.”  Please read pages 4–1 to pages 4–19.  In this reading, you will learn about the first law of thermodynamics for closed systems.  Go through Examples 4.2 and 4.3 carefully.  How do you express the first law of thermodynamics using an equation?

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4.2 The First Law for Open Systems   - Lecture: IIT Kharagpur Lecture Series on Applied Thermodynamics: Professor P.K.Das’ “The first law of thermodynamics (Open Systems)” Link: IIT Kharagpur Lecture Series on Applied Thermodynamics: Professor P.K.Das’ “The first law of thermodynamics (Open Systems)” (YouTube)

Instructions: Please watch this video (50:46 minutes), which will introduce you to the application of the first law of thermodynamics to open systems.  For open systems, mass, heat and work are allowed to cross the system boundary.  This lecture covers subunits 4.2.1-4.2.2.

How would you state the first law for open systems in a sentence?

4.2.1 Conservation of Mass   - Reading: North Carolina State University: Professor Boles' Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” Link: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” (PDF)

Instructions: Please click on “Study Guide for Chapter 4.”  Please read pages 4–20 to pages 4–21.  You will be introduced to the concept of control volume and the principle of conservation of mass.  You will also learn how to apply the principle of mass conservation to general open systems and to specific cases, such as steady-state, steady-flow of incompressible fluid.

4.2.2 Energy Flow   - Reading: North Carolina State University: Professor Boles' Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” Link: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” (PDF)

`````` Instructions: Please click on “Study Guide for Chapter 4.”  Please
read pages 4–21 to pages 4–23.  In this reading, you will learn how
to calculate the energy flowing into and out of a control volume.

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4.3 Steady-State, Steady-Flow Processes (SSSF)   - Reading: North Carolina State University: Professor Boles' Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” Link: North Carolina State University: Professor Boles’ Lecture Notes on Thermodynamics: “Chapter 4: The First Law of Thermodynamics” (PDF)

Instructions: Please click on “Study Guide for Chapter 4.”  Please read pages 4–23 to pages 4–58.  In this reading, you will learn how to apply the first law of thermodynamics to study steady-state, steady-flow (SSSF) processes.  You will also learn to derive mass and energy conservation equations for several basic SSSF processes, including nozzles, diffusers, throttles, pumps, fans, blowers, turbines, compressors, heat exchangers, and mixing chambers.  Make sure that you understand how to use the control volume technique to analyze a variable flow process.  This reading covers subunits 4.3.1-4.3.6.

4.3.1 Nozzles and Diffusers   Note: The reading for this unit is covered by subunit 4.3.

4.3.2 Throttles   Note: The reading for this unit is covered by subunit 4.3.

4.3.3 Pumps, Fans, and Blowers   Note: The reading for this unit is covered by subunit 4.3.

4.3.4 Turbines and Compressors   Note: The reading for this unit is covered by subunit 4.3.

4.3.5 Heat Exchangers   Note: The reading for this unit is covered by subunit 4.3.

4.3.6 Mixing of Streams   Note: The reading for this unit is covered by subunit 4.3.

• Assessment: University of South Florida's Dr. Carlos A. Smith’s “Thermodynamics: Homework A – Set 3” Link: University of South Florida's Dr. Carlos A. Smith’s “Thermodynamics: Homework A – Set 3” (HTML)

Instructions: Please attempt all questions in teh assessment.  You can find the answers here (PDF).

Terms of Use: This resource is used with the kind permission of Dr. Carlos A. Smith.  To view the original assessment on the University of South Florida's website click here (HTML).

4.4 Transient Analysis   - Reading: Queen’s University, Canada: Professor G. Ciccarelli’s Lecture Notes on Applied Thermodynamics: “Lectures 14-15: Control Volume Energy Analysis: Applications” Link: Queen’s University, Canada: Professor G. Ciccarelli’s Lecture Notes on Applied Thermodynamics: “Lectures 14-15: Control Volume Energy Analysis: Applications” (PDF)

Also available in:

``````[EPUB](https://resources.saylor.org/wwwresources/archived/site/wp-content/uploads/2011/07/ME103-4.4-G.-Ciccarelli.epub)

transient analysis for control volume.  Apply this knowledge to
analyze filling of a bottle.

kind permission of G. Ciccarelli, and can be viewed in its original
note that this material is under copyright and cannot be reproduced
in any capacity without explicit permission from the copyright
holder.
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• Assessment: McGraw Hill: Yunus A. Çengel and Michael A. Boles’ Thermodynamics: An Engineering Approach, 4/e: "Multiple Choice Quiz for Chapter 4" Link: McGraw Hill: Yunus A. Çengel and Michael A. Boles’ Thermodynamics: An Engineering Approach, 4/e: "Multiple Choice Quiz for Chapter 4" (HTML)

Instructions: Please click on the link above and answer all 10 questions in the quiz.  Select your answer from the choices given for each question. Click on “Submit Answers” at the bottom of the webpage when you have answered all questions. The webpage will tell you whether your answer is correct and what the correct answer is.

• Assessment: The Saylor Foundation’s “Unit 4 Assessment” Link: The Saylor Foundation’s “Unit 4 Assessment” (PDF)

Instructions: Please click on the link above and download the assessment.  Work through all problems and write down your answers.  Read the instructions for each problem carefully.  Once you complete the assessment, compare your answers with the "Guide To Responding" document (PDF).  This assessment will cover topics discussed in Unit 4.