# ME204: Heat Transfer

Unit 4: Heat Exchangers   Heat exchangers are devices designed to transfer energy from one fluid to another.  You can find heat exchangers in almost any engineering application, ranging from nuclear power plant to the cooling of electronic devices.  Heat exchanges can be found in a wide variety of configurations, but can be generally classified into three basic types: the parallel or counter-flow configuration, the shell-and-tube configuration, and the cross-flow configuration.  In this unit, you will learn about the pros and cons and how to evaluate performance of each configuration.

This unit will take you approximately 14 hours to complete.

☐    Subunit 4.1: 4 hours

☐    Video Lecture: 1 hour

☐    Subunit 4.2: 2 hours

☐    Subunit 4.3: 2 hours

☐    Subunit 4.4: 2 hours

☐    Subunit 4.5: 4 hours

☐    Assignment: 2 hours

Unit4 Learning Outcomes
Upon successful completion of this unit, the student will be able to: - Calculate heat transfer coefficient for heat exchangers. - Apply Number of Transfer Units (NTU) method to calculate the rate of heat transfer in heat exchangers. - Calculate the exit temperatures from inlet conditions and exchanger parameters. - Compare theheat transfer coefficientand NTU methods for analyzing heat exchanger performance.

4.1 Introduction to Heat Exchangers   - Reading: MIT: Professors John Lienhard IV and John Lienhard V’s A Heat Transfer Textbook: “Chapter 3: Heat Exchangers” Link: MIT: Professors John Lienhard IV and John Lienhard V’s A Heat Transfer Textbook: “Chapter 3: Heat Exchangers” (PDF)

`````` Instructions: For this unit, please read “Chapter 3: Heat Exchanger
Design” (pp. 99-129), which will introduce you to heat exchangers.
You will also learn about some basic considerations when designing
heat exchangers.  Practice “Experiment 1” on page 101.  Make sure
you know how to calculate logarithmistic mean temperature difference
(LMTD), which is critical for evaluating performance of heat
transfer coefficient.

displayed on the webpage above.
``````
• Lecture: YouTube: Indian Institute of Technology (IIT) Bombay: Professor S.P.Sukhatme and Professor U.N.Gaitonde’s “Lecture 25: Heat Exchangers-1,” “Lecture 26: Heat Exchangers-2,” “Lecture 27: Heat Exchangers-3,” and “Lecture 28: Heat Exchangers-4”

Link: YouTube: Indian Institute of Technology (IIT) Bombay: Professor S.P.Sukhatme and Professor U.N.Gaitonde’s “Lecture 25: Heat Exchangers-1,” “Lecture 26: Heat Exchangers-2,” “Lecture 27: Heat Exchangers-3,” and “Lecture 28: Heat Exchangers-4” (YouTube).

Instructions: Please watch these videos in their entirety (ranging from 50-60 minutes for each video), which will introduce you to the basic equations and dimensionless numbers for free convection.  These videos will cover the material that you need to know for subunits 4.1-4.5.

• Reading: MIT: Professor Z. S. Spakovszky’s Lecture Notes on Thermodynamics & Propulsion: “Section 18.5: Heat Exchangers”

Link: MIT: Professor Z. S. Spakovszky’s Lecture Notes on Thermodynamics & Propulsion: “Section 18.5: Heat Exchangers” (HTML)

Instructions: Please read the entire page.  This reading will provide you a brief overview of simple heat exchangers. The reading will cover the material that you need to know for subunit 4.1.

• Lecture: YouTube: Stanford University: Professor Channing Robertson’s Introduction to Chemical Engineering: “Lecture 12: Heat Exchangers” Link: YouTube: Stanford University: Professor Channing Robertson’s Introduction to Chemical Engineering: “Lecture 12: Heat Exchangers” (YouTube)

Also available in:
iTunes U

Instructions: Please watch this video (52:06 minutes), which will provide you a simplified overview of heat exchangers. This lecture video covers the material that you need to know for subunits 4.1 and 4.2.

4.2 Overall Heat Transfer Coefficient   Note: This topic is covered by the resources below subunit 4.1.

4.3 Overall Surface Efficiency/Fin Efficiency   Note: This topic is covered by the resources below subunit 4.1.

4.4 Log Mean Temperature Difference   Note: This topic is covered by the resources below subunit 4.1.

4.5 Number of Transfer Units (NTU) Analysis Method   Note: This topic is covered by the resources below subunit 4.1.

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