Difference between open and closed cycle gas turbine.
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Closed Cycle Gas Turbine
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Open Cycle Gas Turbine
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It works on closed cycle. The working fluid is recirculates again and again. It is a clean cycle.
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It works on open cycle. The fresh charge is supplied to each cycle and after combustion and expansion. It is discharged to atmosphere.
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The gases other than the air like Helium or Helium-Carbon dioxide mixture can be used, which has more favorable properties.
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Air-fuel mixture is used which leads to lower thermal efficiency.
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Since heat is transferred externally, so any type of fuel; solid, liquid or gaseous or combination of these can be used for generation of heat.
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Since combustion is an integral part of the system thus it requires high quantity liquid or gaseous fuel for burning in a combustion chamber
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The heat is transferred indirectly through a heat exchanger.
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Direct heat supply. It is generated in the combustion chamber itself
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High thermal efficiency for given lower and upper temperature liquids.
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Low thermal efficiency for same temperature limits.
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Part load efficiency is better.
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Part load efficiency is less compared to Closed cycle gas turbine.
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Reduced size per MWh of power output.
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Comparatively large size for same power output.
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Since combustion products do not come in direct contact of turbine blade, thus there is no blade fouling and longer blade life.
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Direct contact with combustion products, the blades are subjected to higher thermal stresses and fouling and hence shorter blade life.
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Better control on power production.
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Poor control on power production.
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Closed cycle gas turbine plant is complex and costly.
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Open cycle gas turbine plant is simple and less costly.
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