1. 041115© M. Kostic Revisiting The First Law of Energy Conservation Prof. M. Kostic Mechanical Engineering NORTHERN ILLINOIS UNIVERSITY The 2005 International Mechanical Engineering Congress and Exhibition November 5-11, 2005 Walt Disney World Dolphin Hotel, Orlando, Florida, USA

2. 041115© M. Kostic World Energy and Future: Importance of Energy Conservation and Renewable and Alternative Energy Resources 2000 kcal/day  100 Watt USA about 0.3 billion 12,000 Watt/c 1500 W el /c World over 6 billion 2,200 Watt/c 275 W el /c 1.37 kW/m 2 ·12%  165 W/m 2

3. 041115© M. Kostic The two things are certain j (1) the world population and their living-standard expectations will substantially increase (over 6 billion people now, in 50 years 10-11 billion - energy may double) j (2) fossil fuels’ economical reserves, particularly oil and natural gas, will substantially decrease (oil may run out in 30-50 years)

4. 041115© M. Kostic Some Headlines…: j It took World 125 years to consume the first trillion barrels of oil – the next trillion will be consumed in 30 years. j The World consumes two barrels of oil for every barrel discovered. j Only “Human Power” can deliver MORE energy with LOWER emission

5. 041115© M. Kostic Population & Energy: Unrestricted Exponential Growth  About one million years ago our own species, homo sapiens, first appeared, strived most of the history and boomed with agricultural and industrial revolution. We are over 6 billion now. j Standard of living and energy use have been growing almost exponentially due to abundance of resources. j The growth will be naturally restricted with overpopulation and resource depletion as we know it. Time in history Population in millions Most of BC history 10 due to hardship AD 1 300 1750760 18001,000 19502,500 20006,000

6. 041115© M. Kostic The energy “difficulties” … j (1) will be more challenging than what we anticipate now j (2) NO traditional solutions j (3) New knowledge, new technology, and new living habits and expectations will be needed

7. 041115© M. Kostic So, what are we going to do? Do we need CASH for ALCOHOL research?

8. 041115© M. Kostic Earth Energy Balance: j All energy to Earth surface is 99.98 % solar, 0.02% geothermal, and 0.002% tidal-gravitational. j About 13 TW world energy consumption rate now (0.007% of solar striking Earth) is about 7 times smaller than global photosynthesis (all life), the latter is only 0.05% of total solar, and global atmospheric water and wind are about 1% of solar. Source: Basic Research Needs To Assure A Secure Energy Future, ORNL Report, 2003

9. 041115© M. Kostic

10. 041115© M. Kostic Energy: Physics Manuscript by M. Kostic for Dekker's ENCYCLOPEDIA OF ENERGY ENGINEERING AND TECHNOLOGY Outline I. Energy: From Work to Heat to General Concept II. Energy Forms and Classifications: Energy Transfer versus Energy Property III. The First Law of Energy Conservation: Work-Heat-Energy Principle IV. The Second Law of Energy Degradation: Entropy and Exergy V. Concluding Remarks

11. 041115© M. Kostic Energy: Property vs. Transfer

12. 041115© M. Kostic Energy: Property vs. Transfer (2)

13. 041115© M. Kostic Energy: Energy: Different types of energy (a) potential gravitational and electromagnetic radiation; (b) organized energy as work transfer; (c) disorganized thermal energy as heat transfer. (b) (a) (c) m

14. 041115© M. Kostic Energy: Structure, Forces, and Energies TABLE 1: Material system structure and related forces and energies ParticlesForcesEnergies Atom nucleusStrong and weak inter-nucleus Nuclear Electron shellelectromagneticElectrical, magnetic, electromagnetic MoleculesInter-atomic, within molecule chemical MoleculesRandom collision and inertial, Potential inter-molecular Sensible thermal MoleculesPotential inter-molecular Latent thermal MoleculesPotential inter-molecular Mechanical elastic System massInertial and gravitationalMechanical kinetic and gravitational potential

15. 041115© M. Kostic Energy: Physics

16. 041115© M. Kostic Energy: Physics

17. 041115© M. Kostic Energy: Physics Is this “flow” or “elastic” energy?

18. 041115© M. Kostic Energy: Forms of Heat Transfer

19. 041115© M. Kostic Energy Interactions: Coupled, Adiabatic, and Caloric

20. 041115© M. Kostic Energy & Entropy: Control Volume

21. 041115© M. Kostic Entropy: Reversible and Unrestricted Expansions

22. 041115© M. Kostic Entropy (2) If heat or work at higher potential (temperature or pressure) than necessary, is transferred to a system, the energy at excess potential will dissipate spontaneously to a lower potential (if left alone) before new equilibrium state is reached, with entropy generation, i.e. increase of entropy displacement over a lower potential. A system will ‘accept’ energy at minimum necessary (infinitesimally higher) or higher potential. Furthermore, the higher potential energy will dissipate and entropy increase will be the same as with minimum necessary potential, like in reversible heating process, i.e.: However, the source entropy will decrease to a smaller extent over higher potential, thus resulting in overall entropy generation for the two interacting systems,

23. 041115© M. Kostic The Second Law: (A) Kelvin-Plank statement (B) Clausius statement

24. 041115© M. Kostic Heat Engine: Ideal Carnot Cycle

25. 041115© M. Kostic ENERGY Property and Transfer/Exchange j "... Energy is the ‘‘building block’’ and fundamental property of matter and space and, thus, the fundamental property of existence. j Energy exchanges or transfers are associated with all processes (or changes) and, thus, are indivisible from time."

26. 041115© M. Kostic Focus and Goal : Focuses on philosophical and practical aspects of energy and entropy, with emphasis on reversibility and irreversibility, and Goal to better understand the concept and application of Energy Conservation (The 1 st Law), and Energy Degradation (The 2 nd Law)

27. 041115© M. Kostic Objective : … to emphasize known, but not so well-recognized issues about energy and entropy, irreversibility and reversibility, as well as to put certain physical and philosophical concepts in perspective, as well as to put certain physical and philosophical concepts in perspective, and initiate discussion and arguments about the paper theme.