The Stirling engine was invented in 1816 by Robert Stirling as a safer alternative to steam engines. It works by using the expansion and compression of a gas or fluid to convert heat into mechanical energy. The engine has two pistons - a power piston and displacer - that move due to pressure changes from heating and cooling the gas. Heat is applied to one side to expand the gas, pushing the piston, then it cools and contracts on the other side. Its advantages include using various heat sources, being environmentally friendly, and operating safely at low pressures. Applications include power generation, cooling, heating, and marine uses.

1. STIRLING ENGINE

2. HISTORY
 Robert Stirling invented stirling engine in the year 1816.
Thought to replace the steam turbines of his days due to
frequent explosion caused by unsustainable high pressure
killing and injuring workers.
Stirling engine could not explode and produce more power
than the steam engine used.

3. WHAT IS STIRLING ENGINE ?
Device that converts heat energy to
mechanical power by alternately
compressing and expanding a fixed quantity
of working fluid at different temperatures.

4. MAIN COMPONENTS
Power piston – small tightly sealed piston that
moves up when the gas inside the engine expands
Displacer – larger piston and it is very loose in its
cylinder so air can move easily between the heated
cooled sections of the engine as the displacer
moves up and down
These piston move by the action of compression
and expansion.
Difference in pressure causes the piston to move
and produce power.

5. STIRLING ENGINE

6. WORKING PRINCIPLE
I. One side of the engine is continuously heated
while the other side is continuously cooled.
II. First, the air moves to the hot side, where it is
heated and it expands pushing up on a piston.
III. Then the air moves through the regenerator to
the cold side, where it cools off and contracts
pulling down on the piston.
IV. Temperature change inside the engine produces
the pressure change needed to push on the
piston and make the engine run.

7. EFFICIENCY
Theoretically
 Stirling engine efficiency = Carnot efficiency
 Unfortunately working fluid or gas is not ideal this
causes the efficiency to be lower than Carnot
efficiency.

8. ADVANTAGES
Various heat sources (solar, geothermal,
nuclear energy, waste heat, biological)
Environmental friendly
Heat is external and the burning of a fuel-air
mixture can be more accurately controlled.
Operates at relatively low pressure and thus
are much safer than typical steam turbines
Less manpower needed to operate any type
of commercial Stirling engine.

9. APPLICATIONS
Water pump stations
Combined heat and power plant
Solar power generation
Stirling cyrocoolers
Heat pump
Marine engines
Nuclear power
Aircraft engines
Micro CHP

10. STIRLING CYROCOOLERS
 It is mainly used in heavy ships for high heat
production
NUCLEAR POWER
 Replacing the steam turbines of the nuclear
power plant with Stirling engine might simplify
the plant, yield greater efficiency, and reduce
the radioactivity by products.

11. CONCLUSION
Unlimited source of heat source
Political awareness of green heat and power
production.
Large market experiencing rapid growth.
Many different possible applications.
Time to change.