Description: Slide 1: The Second Law of
Slide 2: In the previous lectures, we applied the first law of thermodynamics,
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Slide 4: It is common experience that a cup of hot
Slide 5: As another familiar example, consider the
Slide 6: Finally, consider a paddle-wheel mechanism that
Slide 7: It is clear from these arguments that processes proceed in a certain
Slide 8: This inadequacy of the first law to identify whether a process can take
Slide 9: The Second Law of Thermodynamics
Slide 10: The use of the second law of thermodynamics is not limited to
Slide 11: Heat transfer from industrial sources to the environment is of major
Slide 12: THERMAL ENERGY RESERVOIRS

Slide 13: The atmosphere, for example, does not warm up as a result of heat losses
Slide 14: A reservoir that supplies energy in the form of
Slide 15: HEAT ENGINES

Slide 16: Heat engine is device which converts heat energy into
Slide 17: Internal Combustion Engines
Slide 18: Classification of Internal Combustion Engines
Slide 19: According to the speed of engine:

Slide 20: External Combustion Engines
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Slide 22: Comparison
Slide 23: The term heat engine is often used in a broader sense to include work
Slide 24: The work-producing device that best
Slide 25: The various quantities shown on this
Slide 26: The net work output of this power
Slide 27: These components, together with the
Slide 28: Thermal Efficiency
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Slide 30: Cyclic devices of practical interest such as heat
Slide 31: Notice that both QL and QH are defined as magnitudes and therefore
Slide 32: The thermal efficiency of a heat engine is always less than unity since both
Slide 33: Thus, even with the most efficient heat
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Slide 36: The Second Law of Thermodynamics:
Slide 37: The Kelvin–Planck statement can also be
Slide 38: REFRIGERATORS
Slide 39: Refrigerators, like heat engines, are
Slide 40: The refrigerant enters the compressor
Slide 41: The low-temperature refrigerant then
Slide 42: In a household refrigerator, the
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Slide 44: A refrigerator is shown schematically in
Slide 45: Coefficient of Performance
Slide 46: The conservation of energy principle for a cyclic device requires that
Slide 47: Notice that the value of COPR can be greater than unity.

Slide 48: Heat Pumps
Slide 49: The objective of a heat pump, however, is to
Slide 50: The measure of performance of a heat pump is also expressed in
Slide 51: Air conditioners are basically refrigerators whose
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Slide 55: The Second Law of Thermodynamics:
Slide 56: It simply states that a refrigerator cannot
Slide 57: REVERSIBLE AND IRREVERSIBLE PROCESSES
Slide 58: A reversible process is defined as a process that can be reversed
Slide 59: THE CARNOT CYCLE
Slide 60: The efficiency of a heat-engine cycle greatly depends on how the
Slide 61: Probably the best-known reversible cycle is the Carnot cycle, first
Slide 62: Consider a closed system that
Slide 63: Reversible Isothermal Expansion

Slide 64: Reversible Adiabatic Expansion

Slide 65: Reversible Isothermal Compression

Slide 66: Reversible Adiabatic Compression

Slide 67: The P-V diagram of this cycle is shown in
Slide 68: The Reversed Carnot Cycle
Slide 69: THE CARNOT PRINCIPLES
Slide 70: THE CARNOT HEAT ENGINE
Slide 71: This relation is often referred to as the Carnot
Slide 72: The thermal efficiencies of actual and reversible
Slide 73: The maximum efficiency of a steam power
Slide 74: The thermal efficiency of actual heat engines can be maximized by
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Slide 76: The Quality of Energy

Slide 77: These efficiency values show that energy
Slide 78: Large quantities of solar energy, for example, can be stored in large bodies of water
Slide 79: THE CARNOT REFRIGERATOR AND HEAT PUMP
Slide 80: Then the COP relations for reversible
Slide 81: The coefficients of performance of actual and reversible refrigerators
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