Module 01 Energy Basics Energy Power Forms of energy Thermodynamic laws Entropy / Exergy

1. Module 01 Energy Basics Energy Power Forms of energy Thermodynamic laws Entropy / Exergy Combustion fundamentals

2. A few suggested references Shanthini, R., 2009. Thermodynamics for beginners. Peradeniya: Science Education Unit. All chapters available at: http://www.rshanthini.com/ThermoBook.htm MacKay, D.J.C., 2009. Sustainable energy: without the hot air. Cambridge: UIT Cambridge Ltd. Available at: http://www.withouthotair.com/download.html (also the kindle version)

3. What is energy? – energy is the potential to do work (defined loosely) Energy is not a ‘thing’ or ‘substance’. Energy cannot be seen, heard or felt. Energy is a concept.

4. What is energy? – energy is the potential to do work (defined loosely) What is work? – force exerted over a distance (scientific definition) F F is the force pushing the ball

5. What is energy? – energy is the potential to do work (defined loosely) What is work? – force exerted over a distance (scientific definition) F F is the force pushing the ball

6. What is energy? – energy is the potential to do work (defined loosely) What is work? – force exerted over a distance (scientific definition) F F is the force pushing the ball D is the distance over which the ball is moved D Work = F x D

7. What is energy? – energy is the potential to do work (defined loosely) What is force? – mechanical force (impact of one moving object on another) – gravitational force (force acting between distant masses) – electrical force (attraction and repulsion of changed particles) – magnetic force (attraction and repulsion of magnetic objects) – and more……… Work = Force x Distance

8. What is energy? – energy is the potential to do work (defined loosely) Where else can one find the potential to do work? – in a moving particle (as kinetic energy) – in a mass (Einstein’s contribution: E = mc2) – in a body at a certain temperature (as internal energy) – in a chemical compound (as chemical energy) – in a nuclei (as nuclear energy) – and more…..

9. What is energy? – energy is the potential to do work (defined loosely) What is power? – power is the rate at which work is done Work = Force x Distance Power = Work / Time

10. What is the unit of Energy? What is the unit of Work? What is the unit of Power?

11. Units for energy / work joulein SI-system  1 J(joule) = 1 N·m 1 N (newton) = 1 (kg.m/s2) is the unit of force 1 Pa (pascal) = 1 N/m2 is the unit for pressure J = N·m = (N/m2) · m3 = Pa·m3

12. One joule in everyday life is approximately: The energy required to raise the temperature of cool, dry air by one degree Celsius. A person at rest releases 100 J of heat every second.

13. SI multiples for joules (J) http://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)

14. Units for power wattin SI-system  1 W(watt) = 1 J/s = 1 N.m/s 60 W = 60 J/s = 60 x 60 J/m = 60 x 60 x 60 J/h = 216,000 J/h = 216 kJ/h

15. A person at rest releases 100 J of heat every second. It is equivalent to100 W

16. SI multiples for watts (W)

17. Global Energy Consumption Global primary energy consumption in 2011 = 12274.6 million tonnes of oil equivalent per year 1 tonne of oil equivalent (toe) is the rounded-off amount of energy that would be produced by burning one tonne ( = metric ton = 1000 kg) of crude oil. One tonne of oil equivalent =41.9 gigajoules BP Statistical Review of World Energy June 2012 (bp.com/statisticalreview)

18. Global Energy Consumption Global primary energy consumption in 2011 = 12274.6 million tonnes of oil equivalent per year ≈ 12274.6 x 41.9 million gigajoules per year ≈ 515533 million gigajoules (GJ) per year ≈ 515533 petajoules (PJ) per year [= 515.5 exajoules (EJ) per year] ≈ 1412.42 PJ per day ≈ 58.85 PJ per hour ≈ 0.98085 PJ per min ≈ 980.85 terajoules (TJ) per min ≈ 16.3 TJ per sec ≈ 16.3 terawatts (TW) BP Statistical Review of World Energy June 2012 (bp.com/statisticalreview)

19. Global Energy Consumption Global Consumption ≈ 16.3 TW = 16.3 x1012 W ≈ 271,666,666,666 of 60 W bulbs World population, for mid-year 2011, is estimated at 7,021,836,029. Global Consumption ≈ 38.7 of 60 W bulbs per person in 2011

20. Global Energy Consumption (in TW)

21. What is energy? – energy is the ability to do work (defined loosely) What is work? – force exerted over a distance (scientific definition) Is heat energy too? – heat is a form of energy that flows from a warmer object to a cooler object – work sometimes gets converted to heat (think of examples) – heat sometimes gets converted to work (think of examples)

22. Units for heat Joule / Calorie 1 calorie = the energy needed to raise the temperature of 1 gram of water by 1oC = 4.1868 J (joules) = 0.003 964 BTU (British thermal units)

23. Energy conversion from one unit to another 1 kWh is the energy used by a 1 kW equipment for a duration of 1 hour.

24. For more on energy units and conversions, Visit The American Physical Society Site http://www.aps.org/policy/reports/popa-reports/energy/units.cfm

25. Basic Forms of Energy Kinetic energy: Potential Energy: Thermal (or Heat) Energy: Chemical Energy: Electrical Energy: Electrochemical Energy: Sound Energy: Electromagnetic Energy (light): Nuclear Energy:

26. Basic Forms of Energy (continued) Kinetic Energy: Potential Energy:

27. Hydropower generation Hydroelectric power generation

28. Hydroelectric power generation http://ga.water.usgs.gov/edu/wuhy.html

29. Hydroelectric power generation

30. Hydroelectric power generation

31. Basic Forms of Energy (continued) Electrical Energy: All matter is made up of atoms, and atoms are made up of smaller particles, called protons, neutrons, and electrons. Electrons orbit around the center, or nucleus, of atoms, just like the moon orbits the earth. The nucleus is made up of neutrons and protons. Material, like metals, have certain electrons that are only loosely attached to their atoms. They can easily be made to move from one atom to another if an electric field is applied to them. When those electrons move among the atoms of matter, a current of electricity is created. Source: http://euclidstube.com/poe/Thermodynamics.ppt

32. Basic Forms of Energy (continued) Thermal (or Heat) Energy: Consider a hot cup of coffee. The coffee is said to possess "thermal energy", or "heat energy," which is really the collective, microscopic, kinetic, and potential energy of the molecules in the coffee. Chemical Energy: Consider the ability of your body to do work. The glucose (blood sugar) in your body is said to have "chemical energy" because the glucose releases energy when chemically reacted (combusted) with oxygen. Source: http://euclidstube.com/poe/Thermodynamics.ppt

33. Steam turbine power generation Warning: not a technically complete diagram

34. Basic Forms of Energy (continued) Electrochemical Energy: Consider the energy stored in a battery. Like the example above involving blood sugar, the battery also stores energy in a chemical way. But electricity is also involved, so we say that the battery stores energy "electro-chemically".  Another electron chemical device is a "fuel-cell".  Source: http://euclidstube.com/poe/Thermodynamics.ppt

35. Basic Forms of Energy (continued) Sound Energy: Sound waves are compression waves associated with the potential and kinetic energy of air molecules. When an object moves quickly, for example the head of drum, it compresses the air nearby, giving that air potential energy. That air then expands, transforming the potential energy into kinetic energy (moving air). The moving air then pushes on and compresses other air, and so on down the chain. Source: http://euclidstube.com/poe/Thermodynamics.ppt

36. Basic Forms of Energy (continued) • Electromagnetic Energy (light): • Consider the energy transmitted to the Earth from the Sun by light (or by any source of light). Light, which is also called "electro-magnetic radiation". Why the fancy term? Because light really can be thought of as oscillating, coupled electric and magnetic fields that travel freely through space (without there having to be charged particles of some kind around).   • It turns out that light may also be thought of as little packets of energy called photons (that is, as particles, instead of waves). The word "photon" derives from the word "photo", which means "light".  Source: http://euclidstube.com/poe/Thermodynamics.ppt

37. Basic Forms of Energy (continued) Nuclear Energy: The Sun, nuclear reactors, and the interior of the Earth, all  have "nuclear reactions" as the source of their energy, that is, reactions that involve changes in the structure of the nuclei of atoms. Source: http://euclidstube.com/poe/Thermodynamics.ppt

38. Energy is available in different forms. Energy cannot be created or destroyed (which is a natural law). Energy can change from one form to the other.

39. The study of conversion of energy is known as Thermodynamics. Mostly, it is study of the connection between heat and work, and the conversion of one into the other. Engineering examples: ……………………………………

40. Thermodynamics is based on fundamentals laws, which are the natural laws. These laws have not been proven wrong so far. These laws will remain as fundamental laws until someone finds out that they are wrong. If that happens then we need to redo all thermodynamics that has been developed so far.

41. First Law of Thermodynamics Energy is always conserved. That means, energy cannot be created or destroyed. However, energy can change from one form to the other.

42. First Law of Thermodynamics System Energy of the system E Qin Wout Heat energy that entered the system Work energy that left the system

43. First Law of Thermodynamics E Qin Wout Efinal - Einitial = Qin – Wout ΔE = Qin – Wout

44. First Law of Thermodynamics E Qin Wout ΔE = Qin – Wout = 0 for a system at steady state

45. First Law of Thermodynamics First law is about the balance of quantities of energy. It helps to keep account of what happen to all forms of energy that are involved in a process.

46. Apply First Law to a Heat Engine Steam Turbine Turbine Wout Condenser Warm water Boiler Qout Pump Cold water Qin Turbine gives work to the generator to make electricity Flame gives heat to convert water to steam.

47. Apply First Law to Heat Engine Cold reservoir at TC K A heat engine is a mechanical system. As it cycles through a repetitive motion, transfers heat from a high temperature heat bath to a low temperature bath, and performs work on its environment. Qout Wout Heat Engine Qin Hot reservoir at TH K

48. Apply First Law to Heat Engine Cold reservoir at TC K Qout First law gives the following relationship: Wout Heat Engine Qin = Wout + Qout Qin Hot reservoir at TH K

49. Apply First Law to Heat Engine Steam Turbine Turbine Wout Condenser Warm water Boiler Qout Pump Cold water Qin Hot reservoir is the flame at temperature TH K Cold reservoir is the cold water at temperature TC K

50. Apply First Law to Heat Engine Cold reservoir at TC K We like to have an engine that converts all heat into work. That is, we would like to have Qout Wout Heat Engine Qin = Wout Qin Hot reservoir at TH K