Energy conversion is the process of changing one form of energy into another, a fundamental capability that enables modern civilization to function. It can occur in various ways, from converting the kinetic energy of wind into mechanical power through windmills to transforming solar energy into electrical energy in solar panels. This transformation is essential not just for daily usage but also for harnessing and utilizing natural resources more efficiently. In the context of rural electrification, this process plays a critical role. By converting available local energy resources into electricity, rural communities can access a stable and reliable power supply. This not only improves the quality of life but also supports economic development by powering homes, schools, businesses, and healthcare facilities. Consequently, energy conversion facilitates the broader goal of rural electrification, demonstrating the interconnection between technological innovation and societal advancement.

1. CHAPTER – 1:
Overview of Thermodynamics
• Thermodynamics is the study of energy conversion between heat and
mechanical work, and subsequently the macroscopic variables such as
temperature, volume and pressure.
• The starting points for most thermodynamic considerations are the laws
of thermodynamics.
• The field of thermodynamics studies on the behavior of energy flow
in natural systems.
• The laws of thermodynamics describe some of the fundamental truths
of thermodynamics observed in our universe. These laws are important
because many of the processes studied based on the flow of energy.

2. First Law of Thermodynamics (or) Law of Conservation of
Energy:
• First Law of Thermodynamics states that “Energy can neither be
created nor be destroyed, but it changes from one form to other”. This
is the statement of conservation of energy for a thermodynamic system.
• In any process in an isolated system, the energy remains the same.
• For a thermodynamic cycle, the net heat supplied to the system equals
to the net work done by the system.

3. Second Law of Thermodynamics:
• The Second Law of Thermodynamics states that “Heat can
spontaneously flow from a higher temperature region to a lower
temperature region, but not the other way around”.
• For example, a cup of hot coffee left on a table eventually cools, but a
cup of cool coffee in the same room never gets hot by itself.

4. Cont.…
• The Second Law of Thermodynamics also states that “Energy systems
have a tendency to increase their entropy rather than decrease it”.
• In all energy exchanges, if no energy enters or leaves the system, the
potential energy of the state will always be less than that of the initial
state. This is commonly referred to as Entropy.

5. Carnot Cycle:
• The Carnot cycle is a theoretical thermodynamic cycle proposed
by Nicolas Léonard Sadi Carnot in 1824.
• A system undergoing a Carnot cycle is called a Carnot heat engine.
• Carnot developed the foundation of the second law of thermodynamics,
and is often described as the "Father of thermodynamics."
• The Carnot cycle consists of the following four processes:

6. Cont.…
I. A reversible isothermal gas expansion process. In this process, the
ideal gas in the system absorbs qin amount heat from a heat source at a
high temperature Th, expands and does work on surroundings.
II. A reversible adiabatic gas expansion process. In this process, the
system is thermally insulated. The gas continues to expand and do
work on surroundings, which causes the system to cool to a lower
temperature, Tl.
III. A reversible isothermal gas compression process. In this process,
surroundings do work to the gas at Tl, and causes a loss of heat, qout.
IV. A reversible adiabatic gas compression process. In this process, the
system is thermally insulated. Surroundings continue to do work to the
gas, which causes the temperature to rise back to Th.

7. Cont.…
Figure : An ideal gas-piston model of the Carnot cycle.

8. Cont.…
P-V Diagram
• The P-V diagram of the Carnot cycle is shown in Figure below.
Figure 2: A P-V diagram of the Carnot Cycle.

9. Cont.…
T-S Diagram
• The T-S diagram of the Carnot cycle is shown in Figure below.
Figure: A T-S diagram of the Carnot Cycle.
Efficiency
• Efficiency = net work done by heat engine / heat absorbed by heat engine
= (Th − Tl) / Th .

10. Thermodynamic Process:
• Isothermal Process: A process with no change in temperature.
• Adiabatic Process: A process with no heat transfer into or out of the
system.
• Isochoric Process: A process with no change in volume, in which the
system does not work.
• Isobaric Process: A process with no change in pressure.

11. Home work - 1
1. List at least five devices that operates on thermodynamic
principle and explain their principles of operation.