Summary

• Latent heat
• 1^st law of thermodynamics
• Hero's engine

• Heat engines
  • heat engine diagram
  • Animated applet
  • actual efficiency
  • 2^nd law of thermodynamics
  • max theoretical efficiency
    Example #1
    
    Example #2
    
    Example #3
    
  • LN₂ & Stirling engine demo, animation
  
  
• Internal combustion engines (for the curious)
  • Animated applet
  • The Otto Cycle
  
  
• Refrigerators
  • diagrams
  • Animated applet
    Example #4
    
  • Coefficient Of Performance
    Example #5
    
    Example #6
    
    Example #7
    
  
  

 
What input energy is required if a heat engine performs 200 kJ of work and exhausts 600 kJ of heat?
A. 200 kJ           B. 400 kJ           C. 600 kJ           D. 800 kJ
Answer













 
A heat engine takes in 1000 J of energy at 1000 K and exhausts 700 J at 400 K. What is the actual efficiency of this heat engine?
A. 30 %           B. 40 %           C. 60 %           D. 70 %
Answer













 
What is the theoretical maximum efficiency of this heat engine?
A. 30 %           B. 40 %           C. 60 %           D. 70 %
Answer













 
A refrigerator uses 500 J of work to remove 2000 J of heat from a room. How much heat does it exhaust?
A. 500 J           B. 1500 J           C. 2000 J           D. 2500 J
Answer













 
Can the coefficient of performance of a refrigerator be greater than one?
     A. Yes           B. No

Answer













An air conditioner removes 2000 J from a 20 �C room and expels 2100 J to the outside at 30 �C. What is the actual coefficient of performance?
A. 0.050           B. 0.952           C. 1.05           D. 20
Answer













 
What is the maximum theoretical COP of the refrigerator in the previous question?
A. 0.936           B. 1.00           C. 2.00           D. 29.3
Answer













 



D. 800 kJ


















 



A. 30 %


















 



C. 60 %


















 



D. 2500 J


















 



A. Yes


















 



D. 20


















 



D. 29.3