STIRLING Engine 2 - · PDF fileStirling Engine In Lines • Closed- cycle regenerative heat...
Transcript of STIRLING Engine 2 - · PDF fileStirling Engine In Lines • Closed- cycle regenerative heat...
Stirling Engine
Operation Principles,
Performance and Applications
Prepared by :
Ehab Foda
Mohamed Hamdy
Stirling Engine In Lines
• Closed- cycle regenerative heat engine
• External heat engine
• The core component of the domestic combined heat and power plant (CHP).
Stirling engine is:
a closed-cycle regenerative heat engine with a gaseous working fluid.
Operation Principle
• "Closed-cycle" means that the working fluid is
permanently contained within the engine (there
is no inlet or exit valve).
• "Regenerative" refers to the use of an internal
heat exchanger called a regenerator which
increases the engine's thermal efficiency.
Stirling engine needs only to be connected to a
heat source and a heat sink
Operation Principle
Operation Principle
• Alpha type
• Beta type
• Gamma type
The Alpha type engine relies on interconnecting
the power pistons of multiple cylinders to move
the working gas, with the cylinders held at
different temperatures.
1 and 3 Isothermal
2 and 4 constant volume
The Alpha type engine
relies on interconnecting
the power pistons of
multiple cylinders to
move the working gas,
with the cylinders held at
different temperatures.
Gamma Type Stirling Engines
Operation Principle
The Beta and Gamma type Stirling engines use a
displacer piston to move the working gas back
and forth between hot and cold heat exchangers
in the same cylinder.
Beta Type Stirling Engines
Beta type engines have a displacer and power
piston
Gamma Type Stirling Engines
Gamma type engines have a displacer and power piston,
This type allows a convenient complete separation
between the heat exchangers associated with the
displacer cylinder and the compression and expansion
work space associated with the piston.
Performance
Stirling Engine efficiency
• Theoretical
Stirling engine efficiency = carnot efficiency
(But because of non ideal properties of the working
gas it is less than carnot efficiency)
• Actually it depends on
Temperature Ratio (proportionally)
Pressure Ratio (inversely proportional)
Specific heat ratio (inversely proportional)
Stirling Engine Specific Power
• Specific power = power output / engine (Kg)
• Actually it depends on
Temperature Ratio (proportionally)
Pressure Ratio (proportionally)
Stirling Engine Limitations
• Non ideal properties of the working gas
• Engine Material Properties
1. Friction (Lubricating oil….series explosion hazard)
2. Thermal conductivity (engine size)
3. Creep
4. Tensile strength (high Pr provides high Power)
5. Rupture strength (high Pr provides high Power)
6. Melting Point (high Tr provides high efficiency)
Applications
• Water pump stations
• combined heat and power plant
• Solar power generation
• Stirling cryocoolers
• Heat pump
• Marine engines
• Nuclear power
• Aircraft engines• MicroCHP
Applications
• Water pump station
• A Stirling engine used for pumping water can be configured so that the water cools the compression space. This is most effective when pumping cold water.
Applications
• combined heat and power plant
– Stirling engine is the core component of the domestic
combined heat and power plant (CHP). Where it can run directly on any available heat source.
• Solar power generation
– Stirling engine can convert solar energy to electricity
with an efficiency better than non-concentrated
photovoltaic cells, and comparable to Concentrated Photo Voltaics.
Applications
• Stirling cryocoolers
– Any Stirling engine will also work in reverse as a heat
pump: i.e. when a motion is applied to the shaft, a temperature difference appears between the
reservoirs.
• Heat pump
– A Stirling heat pump is very similar to a Stirling cryocooler, the main difference being that it usually
operates at room-temperature and its principal application to date is to pump heat from the outside of
a building to the inside, thus cheaply heating it.
Applications
• Marine engines
– They can be built to run quietly and without an air
supply, for air-independent propulsion use in submarines.
• Nuclear power
– Replacing the steam turbines of nuclear power plants with Stirling engines might simplify the plant, yield
greater efficiency, and reduce the radioactive by-products.
Applications
• Aircraft engines
– They are quieter, less polluting, gain efficiency with
altitude due to lower ambient temperatures, are more
reliable due to fewer parts and the absence of an ignition system, produce much less vibration
(airframes last longer) and safer, less explosive fuels may be used.
– However, the Stirling engine often has low power
density compared to the commonly used Otto engine
and Brayton cycle gas turbine.
Applications
• MicroCHP
– Stirling engines would supply the client with hot water, space heating and a surplus electric power that could be fed back into the electric grid.
– Stirling engined microgeneration is the most cost effective of various microgeneration technologies in terms of reducing CO2
Conclusions
• Unique Technology
• Large market experiencing rapid growth
• Political awareness of green heat and power production
• Fuel independency
• Many different possible applications
• Many different geographical markets
• Many different customer types
Kiitos!