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Thermodynamics

Thermodynamics. ENTC 370. Announcements. Course Syllabus Class Webpage http://etidweb.tamu.edu/classes/entc370/ Classnotes in Power Point Homework assignments and solutions Announcements eCampus Grades will be regularly posted through eCampus Lab Manual (next slide)

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Thermodynamics

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  1. Thermodynamics ENTC 370

  2. Announcements • Course Syllabus • Class Webpage • http://etidweb.tamu.edu/classes/entc370/ • Classnotes in Power Point • Homework assignments and solutions • Announcements • eCampus • Grades will be regularly posted through eCampus • Lab Manual (next slide) • Post other material/annoucements

  3. Announcements • Labs • A lab manual is available for this course • Just go to eCampus to download electronic version of lab manual (PDF file) • Lab exercises: 40% Computational (EES) + 60% Hands On • No labs this week

  4. What is Thermodynamics? • Is the science of energy • Deals with energy transformations, including heat and work, and the physical properties of substances involved in the transformation (Jones & Hawkins, 1986) • Conservation of Energy Principle: Energy cannot be created or destroyed, only transformed

  5. What is Thermodynamics? • Thermodynamics is used to describe and understand energy systems • All energy systems are constrained by the laws of physics (1st and 2nd Laws of Thermodynamics) • 1st law of Thermodynamics: Expression of Conservation of Energy Principle • 2nd Law of Thermodynamics: Energy also has quality, energy processes occur in the direction of decreasing quality • Heat flows from Hotto Cold

  6. What is Energy? • In physics, energy is a conserved extensive property of a physical system, which cannot be observed directly but can be calculated from its state. • It is impossible to give a comprehensive definition of energy because of the many forms it may take, but the most common definition is that it is the capacity of a system to perform work. • EIA (Energy Information Agency): http://www.eia.gov/energyexplained/index.cfm?page=about_home

  7. Why is Thermodynamics Important? • Energy affects the World Economy • Energy is used everyday by everyone • For design and analysis of thermal systems or to understand how energy is produced or consumed • Depending on the source, it can be renewable or non-renewable • Renewable: Wind, Solar, Geothermal, Tidal • Non-renewable: Fossil Fuels (Oil, Coal, Tar, Wood), Nuclear Fuel • http://www.eia.doe.gov/ • http://www.eia.doe.gov/oil_gas/petroleum/info_glance/petroleum.html

  8. Sources of Energy http://www.eia.gov/energyexplained/index.cfm?page=about_sources_of_energy

  9. Uses of Energy

  10. Fuel Used for Transportation

  11. Energy Consumption Vs. Time Forecasts: http://www.eia.gov/forecasts/ieo/

  12. How is Energy Transformed, Used and Delivered? → Energy Systems

  13. Energy System: Steam Power Plant

  14. Nuclear Power Plant http://science.howstuffworks.com/nuclear-power2.htm http://news.bbc.co.uk/2/shared/spl/hi/sci_nat/05/nuclear_fuel/html/mining.stm

  15. Examples of Energy System: Boilers Water-tube boilers Fire-tube boiler http://science.howstuffworks.com/

  16. Example of Energy System: Gas Turbine http://science.howstuffworks.com/ http://en.wikipedia.org/wiki/Gas_turbine http://www.rolls-royce.com/interactive_games/journey03/index.html

  17. Energy System Example: Car Engine http://auto.howstuffworks.com/engine.htm http://www.youtube.com/watch?v=sZF6BZeWvUw

  18. Car (Gasoline or Diesel) Engine • http://auto.howstuffworks.com/engine3.htm • http://auto.howstuffworks.com/diesel1.htm Other Engines • Thermoelectric: Direct conversion of thermal energy to electricity (Seebeck effect) • Stirling Engine: External Combustion Engine • http://videos.howstuffworks.com/planet-green/30320-g-word-sun-catchers-video.htm

  19. Energy System Example: Refrigeration and Air Conditioning Refrigeration Units Air Conditioning Unit http://www.rdisystems.com/minisite/service/refrigeration-animation http://science.howstuffworks.com/

  20. Purpose and Objective • Understand the key concepts in thermodynamics (i.e. physical properties, laws of thermodynamics, etc.) • Use of the 1st and 2nd law, system conditions and material properties to solve real problems • “Don’t want to shoot in the dark” • Used to determine what is possible or impossible • Learn how to logically and methodically solve thermodynamics problems • Lifelong skills: known + methodology => Solution (unknown)

  21. Thermodynamic Systems:Open or Closed • System is: • Quantity of matter or region of space chosen for study and analysis • Surroundings are: • Region outside the system Surroundings System Boundary

  22. Closed System • Closed system: • Fixed mass and no mass can enter or leave system • Energy can cross boundary and boundary can move (Example: Piston-Cylinder device) Closed System No mass transfer Heat transfer

  23. A closed system consists of a fixed amount of mass and no mass may cross the system boundary. The closed system boundary may move. Examples of closed systems are sealed tanks and piston cylinder devices (note the volume does not have to be fixed). However, energy in the form of heat and work may cross the boundaries of a closed system. Piston-Cylinder Device Rigid Container

  24. Open System • Open system or control volume: • Mass and energy can cross boundary • Examples: Compressors, turbines, and nozzles Open System Mass transfer Heat transfer

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