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ME303: Thermal-Fluid Systems

Unit 5: Heat Exchangers   Heat exchangers are commonplace in a wide variety of situations that you encounter on a daily basis.  They involve the transfer of heat energy from one fluid to another through physical proximity and involve simultaneous conductive and convective heat transfer.  Some common examples include the radiators (a bit of a misnomer) used to remove heat from automobile engines, the coils used to transfer heat from the inside of a refrigerator to the outside, the large ears of some mammals (which can aid in cooling), and the fins on a computer chip.  In this unit, you will learn about the importance of fluid mechanics, exchanger geometry, and flow configuration in heat exchanger efficiency.

Unit 5 Time Advisory
This unit should take you 24 hours to complete.

☐    Introductory Reading: 6 hours

☐    Subunit 5.1: 1 hour

☐    Subunit 5.2: 1 hour

☐    Subunit 5.3: 2 hours

☐    Subunit 5.4: 10 hours

☐    Subunit 5.5: 3 hours

☐    End of Unit Self-Assessment: 1 hour

Unit5 Learning Outcomes
Upon successful completion of this unit, the student will be able to:

  • Define and quantify viscosity, thermal conductivity, heat capacity, and density for various fluids.
  • Determine heat-transfer coefficients for physical situations.
  • Apply those heat-transfer coefficients together with geometrical considerations for the analysis of heat exchangers and solar collectors.

  • Reading: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” Link: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” (PDF)
     
    Also available in:

    EPUB

    Instructions: If you need a review of the fundamentals of heat transfer, these notes may be useful.  Click on the “PDF” hyperlink after the title “Fundamentals of Heat Transfer” for lecture 3 to download the text.  Reserve these notes for reference throughout this unit.  Section 8 of these notes on Heat Exchangers will be particularly useful for supplementing the video lectures later in this unit; please study it in detail.  At this stage you should review Sections 1.0 “Heat Transfer Modes” and 2.0 “Conduction Heat Transfer.”
     
    Terms of Use: This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.  It is attributed to Zoltan Spakovszky and can be found in its original form here.

  • Reading: OnlineFreeEbooks.net: Leinhard and Leinhard’s “A Heat Transfer Textbook”

    Reading: OnlineFreeEbooks.net: Leinhard and Leinhard’s “A Heat Transfer Textbook”

     
    Link: Leinhard and Leinhard’s “A Heat Transfer Textbook” (PDF)
     
    Instructions: This link may be a useful resource for reviewing the basics of heat transfer.  Please refer to text on this webpage if so needed.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Lecture: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Heat Exchangers1,” “Heat Exchangers 2,” and “Heat Exchangers 3” Links: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Heat Exchangers 1,” (YouTube) “Heat Exchangers 2,” (YouTube) “Heat Exchangers 3” (YouTube)
     
    Instructions: You may wish to view these lectures first before studying the written material and then revisit them before completing the unit.  They give an overview of classification, operation, and analysis of heat exchangers.  Note that there are approximately three hours of lecture here.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.1 Temperature-Dependent Fluid Properties   - Reading: Wikipedia’s “Thermal Conductivity,” “Heat Capacity,” “Viscosity,” and “Density” Links: Wikipedia’s “Thermal Conductivity,” (PDF) “Heat Capacity,” (PDF) “Viscosity,” (PDF) and “Density” (PDF)
 
Instructions: Read each of these articles to learn the appropriate units for each quantity and the approximate values for common solids, liquids, and gases.
 
Terms of Use: The articles above are released under a Creative Commons Attribution-Share-Alike License 3.0 (HTML).  You can find the original Wikipedia versions of these articles here (HTML), here (HTML), here (HTML), and here (HTML).

5.2 Geometrical Flow Configuration of Heat Exchangers   - Reading: Engineer’s Guide: “Basic Description of Heat Transfer Equipment” Blog Entry Link: Engineer’s Guide: “Basic Description of Heat Transfer Equipment” (PDF) Blog Entry
 
Instructions: Read this blog entry with particular emphasis on understanding the categorizations of heat exchanger types and configurations.  Specifically, you should learn what is meant by cocurrent or parallel flow, countercurrent flow, and cross flow heat exchangers.
           
Terms of Use: This material is in the public domain. 

5.3 Analysis of Heat Exchanger Performance   5.3.1 Heat—Transfer Coefficients   - Reading: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” Link: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” (PDF)

 Also available in:  

[EPUB](http://www.saylor.org/site/wp-content/uploads/2011/07/ME303-5-Zoltan-Spakovszky.epub)  
    
 Instructions: Click on the “PDF” hyperlink after the title
“Fundamentals of Heat Transfer” for section 3 to download the text. 
You reviewed this material at the beginning of this unit.  Closely
study pages HT 25 – HT 33 this time around.  
    

Terms of Use: This work is licensed under a [Creative Commons
Attribution-NonCommercial-ShareAlike 3.0 United States
License](http://creativecommons.org/licenses/by-nc-sa/3.0/us/).  It
is attributed to Zoltan Spakovszky and can be found in its original
form
[here](http://ocw.mit.edu/courses/aeronautics-and-astronautics/16-050-thermal-energy-fall-2002/lecture-notes/).<span
class="Apple-style-span"
style="font-family: arial; font-size: small; color: rgb(0, 0, 0); "><span
class="Apple-style-span"
style="font-family: arial, sans, sans-serif; font-size: 13px; white-space: pre; ">
</span></span>

5.3.2 Energy Balances and Efficiency   - Reading: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” Link: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” (PDF)

 Also available in:  

[EPUB](http://www.saylor.org/site/wp-content/uploads/2011/07/ME303-5-Zoltan-Spakovszky.epub)  
    
 Instructions: Click on the “PDF” hyperlink after the title
“Fundamentals of Heat Transfer” for section 3 to download the text. 
You reviewed this material at the beginning of this unit.  This time
around, focus on pages HT 45 – HT 53.  Pay particular attention to
the concepts of local balances, overall balances, and overall
transfer efficiency.  
    

Terms of Use: This work is licensed under a [Creative Commons
Attribution-NonCommercial-ShareAlike 3.0 United States
License](http://creativecommons.org/licenses/by-nc-sa/3.0/us/).  It
is attributed to Zoltan Spakovszky and can be found in its original
form
[here](http://ocw.mit.edu/courses/aeronautics-and-astronautics/16-050-thermal-energy-fall-2002/lecture-notes/).<span
class="Apple-style-span"
style="font-family: arial; font-size: small; color: rgb(0, 0, 0); "><span
class="Apple-style-span"
style="font-family: arial, sans, sans-serif; font-size: 13px; white-space: pre; ">
</span></span>

5.4 Fluid Mechanics and Heat Transfer   5.4.1 Natural Convection   - Lecture: YouTube: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Natural Convection 1,” “Natural Convection 2,” and “Natural Convection 3” Links: YouTube: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Natural Convection 1,” (YouTube) “Natural Convection 2,” (YouTube) and “Natural Convection 3” (YouTube)
 
Instructions: Watch the first of the three videos, "Natural Convection 1" (YouTube), in detail (51:46 minutes), and the remaining two videos are optional for viewing.  The main objectives here are to understand when natural convection might be significant and to quantify it via dimensionless correlations with an aim toward calculation of a heat-transfer coefficient.  This is background material which will not be tested directly.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.4.2 Forced Convection   - Lecture: YouTube: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Forced Convection 1,” “Forced Convection 2,” Forced Convection 3,” and “Forced Convection 4” Links: YouTube: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Forced Convection 1,” (YouTube) “Forced Convection 2,” (YouTube) Forced Convection 3,” (YouTube) and “Forced Convection 4” (YouTube)
 
Instructions: Please view and listen to the first video “Forced Convection 1” (YouTube) in detail; you may study the remaining videos as interested.  The main objectives are to understand when forced convection might be significant and to quantify it via dimensionless correlations with an aim toward calculation of a heat-transfer coefficient.  This material should be a review of what you have studied in ME204: Heat Transfer (HTML).  Watch the first video in detail.  This is background material which will not be tested directly.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.4.3 Boundary Layers   - Lecture: YouTube: IIT Bombay: Professor Eldho’s “Introduction to Boundary Layer Theory” Link: YouTube: IIT Bombay: Professor Eldho’s “Introduction to Boundary Layer Theory” (YouTube)
 
Instructions: Review the video (approximately 53 minutes) with a goal of understanding the relationship between heat-transfer coefficients and fluid mechanics.  This material should be a review of what you have studied in ME204: Heat Transfer (HTML) and will not be directly tested for this course.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.4.4 Phase Changes and Heat Transfer   - Lecture: YouTube: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Boiling and Condensation 1,” “Boiling and Condensation 2,” “Boiling and Condensation 3,” and “Boiling and Condensation 4” Links: YouTube: IIT Bombay: Professor Sukhatme and Professor Gaitonde’s “Boiling and Condensation 1,” (YouTube) “Boiling and Condensation 2,” (YouTube) “Boiling and Condensation 3,” (YouTube) and “Boiling and Condensation 4” (YouTube)
 
Instructions: Please view the first of these lectures titled “Boiling and Condensation 1” in its entirety (approximately 56 minutes).  The remaining lectures are optional and may be viewed based on your interests.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

5.5 Solar Collectors   5.5.1 Radiation from/to Surfaces   - Reading: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” Link: MIT: Professor Zoltan Spakovszky’s “Heat Transfer” (PDF)
 
Also available in:

[EPUB](http://www.saylor.org/site/wp-content/uploads/2011/07/ME303-5-Zoltan-Spakovszky.epub)  

 Instructions: Click on the “PDF” hyperlink after the title
“Fundamentals of Heat Transfer” for section 3 to download the text. 
You reviewed this material at the beginning of this unit.  This time
around, study pages HT 54 – HT 66.  
    

Terms of Use: This work is licensed under a [Creative Commons
Attribution-NonCommercial-ShareAlike 3.0 United States
License](http://creativecommons.org/licenses/by-nc-sa/3.0/us/).  It
is attributed to Zoltan Spakovszky and can be found in its original
form
[here](http://ocw.mit.edu/courses/aeronautics-and-astronautics/16-050-thermal-energy-fall-2002/lecture-notes/).<span
class="Apple-style-span"
style="font-family: arial; font-size: small; color: rgb(0, 0, 0); "><span
class="Apple-style-span"
style="font-family: arial, sans, sans-serif; font-size: 13px; white-space: pre; ">
</span></span>

5.5.2 Collectors, Transfer Fluids, and Storage Systems   - Reading: U. S. Department of Energy’s “Solar Water Heaters” Link: U. S. Department of Energy’s “Solar Water Heaters” (PDF)
 
Instructions: Read this link with particular attention to the types of collectors, transfer fluids, and energy storage systems.
 
Terms of Use: This material is part of the public domain. 

Unit 5 Assessment   - Assessment: The Saylor Foundation’s “ME303: Unit 5 Quiz” Link: The Saylor Foundation’s “ME303: Unit 5 Quiz
 
Instructions: Please complete the linked assessment.
 
You must be logged into your Saylor Foundation School account in order to access this quiz.  If you do not yet have an account, you will be able to create one, free of charge, after clicking the link.