University Of Gujrat

• Titel of presentationStrilling and Ericson cycle application’s

Bs Mechanical 2nd SmesterPresent By:

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Stirling Cycle & its Applications

What is a Stirling Engine?• Device that converts heat energy to

mechanical power by alternately compressing and expanding a fixed quantity of working fluid at different temperatures is called stirling Engine.

• External Combustion Engine.

History:-

• Inventor = Robert Stirling.• Stirling Engine replace the

steam turbines of his days due to frequent explosion caused by unsustainable high pressure killing and injuring workers.

• Stirling engine invented in 1816 which could not explode and produce more power then the steam engine used.

Idealised Stirling Cycle

• 1-2 isothermal expansion heat addition from external source.• 2-3 const. volume internal heat transfer from the gas to the

regenerator.• 3-4 isothermal compression heat rejection to the external sink.• 4-1 const. volume heat transfer internal heat transfer from the

regenerator to the gas.

Alpha Stirling Engine

Beta Stirling Engine

Why use Stiriling Engine?• The Stirling cycle engine is environmental harmless and

high theoretical efficiency and almost silent operation.

• Plenty heat sources can be employed on Stirling engine including combustable materials, agricultural waste, biomass, biogas, solar energy and so on.

• The fuel ,the combustion air and the products of combustion do not enter the engine cyclinder to become working gas.

• It is closed cyclic system.

APPLICATIONS OF STIRILING ENGINE:-1.Stirling Engines for Pumping Water using Solar Energy as a source of Power

•Limited availability of petroleum product and electricity in rural areas and high demandable human need for water; make demand for searching another alternative for pumping water.

•One optional and potential engine solving this problem is the solar Stirling engine

• In this system, the solar heat collector provides heat for the solar Stirling engine which in turn provides AC power. The electrical power can be transferred to a battery charger.

•Cost of the equipment is low comparetively.

•Solar Stirling engine will give good hope and way for pumping water in rural areas.

 

• Solar Stirling engine

• Uses reflected sun rays as heat source

• Green energy• Could power a

house

http://www.researchdata.us/Images/Stirlingdish2.jpg

• Very large solar Stirling engine Could probably power a small city.

http://www.tommccarty.com/blog/wp-content/uploads/2008/08/brightsource-solar-mojave2.jpg

2. WASTE HEAT RECOVERY USING STIRLING ENGINE

Different Energy Utilization Systems:-

a) Thermal Power Plantb) Nuclear Power Plantc) Gas Turbine Power Plantd) Process Industriese) Automotive Applications

Drawbacks of above Mentioned Energy Utilization Systems:-

All the systems use large amount of fossil fuels and reject large amount of energy to the atmosphere thus causing global warming, and wastage of fuel.

Types of waste heat recovery systems are;

1) Recuperators, 2) Regenerator, 3) Heat wheels, 4) Heat pipe.

Above mentioned waste heat recovery systems can utilise high and medium temperature waste heat only. They cannot recover low temperature waste heat effectively. So if we want to recover low and very low temperature waste heat we can go for STIRLING ENGINE, which can recover any kind of low grade waste heat because it is external combustion engine and also its efficiency is very good.

• In other words, the engine needs to warm up to obtain and produce the useful power.

• The engine can not change its power output quickly.

Advantages of Stiriling Engine:-

• Stirling engines can run directly on any available heat source.

• A continuous combustion process can be used to supply heat, so those emissions associated with the intermittent combustion processes of a reciprocating internal combustion engine can be reduced.

• The engine mechanisms are in some ways simpler than other reciprocating engine types. No valves are needed,

• A Stirling engine uses a single-phase working fluid which maintains an internal pressure close to the design pressure, and thus for a properly designed system the risk of explosion is low. In comparison, a steam engine uses a two-phase gas/liquid working fluid, so a faulty overpressure relief valve can cause an explosion.

• Waste heat is easily harvested (compared to waste heat from an internal combustion engine) making Stirling engines useful for dual-output heat and power systems.

Disadvantages of Stiriling Engine:-

• The engine is complex due to use of heaters regenerators coolers.

• The cost of the engine is high.

• Stiriling engine requires a blower to force air through preheater and combustion chamber ,this reduces engine efficiency and noise

Ericsson Cycle

Ericsson Cycle• The Ericsson cycle is named after

inventor John Ericsson, who designed and built many unique heat engines based on various thermodynamic cycles.

• He is credited with inventing two unique heat engine cycles and developing practical engines based on these cycles.

Ericsson Cycle• His first cycle is now known as the closed Brayton cycle, while

his second cycle is what is now called the Ericsson cycle.

• The Ericsson cycle consists of two isothermal and two constant pressure processes.

• The p-V and T-s diagram with the mainframe structure of Ericsson Cycle is shown in Fig.1.2:

Ericsson Cycle

Ericsson Cycle• The processes taking place in Ericsson cycle is given

below:

a) Process 1-2: At a constant temperature the pressure of air is increased, therefore the compression takes place.

b) Process 2-3: The increased pressure during this process is maintained and further heat is added to the cylinder.

Ericsson Cyclec) Process 3-4: Now, the temperature is again maintained

constant and the volume of air increases. Therefore the expansion takes place.

d) Process 4-1: Again maintaining the pressure constant, heat is removed from the cylinder system. Hence the process reaches to its initial state, making the process reversible cyclic process.

Ericsson Cycle

• Application of Ericsson Cycle:

Ericsson EngineEricsson Cycle Engine

Thank you!