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  1. 1. presented BY :- Pratik gupta (eee 6TH SEM )
  2. 2. CONTENTS:-  Introduction  Types of cogeneration systems  Benefit of cogeneration  Energy efficiency
  3. 3. Introduction:-  Cogeneration is also called CHP system.  Generation of multiple forms of energy in one system: heat and power  Defined by its “prime movers” • Reciprocating engines • Combustion or gas turbines, • Steam turbines • Microturbines • Fuel cells
  4. 4. Type of Cogeneration Systems:- • Steam turbine • Gas turbine • Reciprocating engine • Other classifications:  - Topping cycle  - Bottoming cycle
  5. 5. Steam Turbine Cogeneration System:- • Widely used in CHP applications • Oldest prime mover technology • Capacities: 50 kW to hundreds of MWs • Thermodynamic cycle is the “Rankin cycle” that uses a boiler • Most common types • Back pressure steam turbine • Extraction condensing steam turbine
  6. 6. • Steam exits the turbine at a higher pressure than the atmospheric Back Pressure Steam Turbine Fuel Figure: Back pressure steam turbine Advantages: -Simple configuration -Low capital cost -Low need of cooling water -High total efficiency Disadvantages: -Larger steam turbine Boiler Turbine Process HP Steam Condensate LP Steam
  7. 7. • Steam obtained by extraction from an intermediate stage • Remaining steam is exhausted • Relatively high capital cost, lower total efficiency Extraction Condensing Steam Turbine Boiler Turbine Process HP Steam LP Steam Condensate Condenser Fuel Figure: Extraction condensing steam turbine
  8. 8. • Operate on thermodynamic “Brayton cycle” • atmospheric air compressed, heated, expanded • excess power used to produce power • Natural gas is most common fuel • 1MW to 100 MW range • Rapid developments in recent years • Two types: open and closed cycle Gas Turbine Cogeneration System
  9. 9. • Open Brayton cycle: atmospheric air at increased pressure to combustor Open Cycle Gas Turbine Air G Compressor Turbine HRSG Combustor Fuel Generator Exhaust Gases Condensate from Process Steam to Process • Old/small units: 15:1 New/large units: 30:1 • Exhaust gas at 450- 600 oC • High pressure steam produced: can drive steam turbine Figure: Open cycle gas turbine cogeneration
  10. 10. • Working fluid circulates in a closed circuit and does not cause corrosion or erosion • Any fuel, nuclear or solar energy can be used Closed Cycle Gas Turbine Heat Source G Compressor Turbine Generator Condensate from Process Steam to Process Heat Exchanger Figure: Closed Cycle Gas Turbine Cogeneration System
  11. 11. 11 • Used as direct mechanical drives Reciprocating Engine Cogeneration Systems Figure: Reciprocating engine cogeneration system • Many advantages: operation, efficien cy, fuel costs • Used as direct mechanical drives • Four sources of usable waste heat
  12. 12. 12 © UNEP 2006 • Supplied fuel first produces power followed by thermal energy • Thermal energy is a by product used for process heat or other • Most popular method of cogeneration Topping Cycle
  13. 13. Bottoming Cycle • Primary fuel produces high temperature thermal energy • Rejected heat is used to generate power • Suitable for manufacturing processes
  14. 14. • Increased efficiency of energy conversion and use • Lower emissions, especially CO2 • Ability to use waste materials • Large cost savings • Opportunity to decentralize the electricity generation • Promoting liberalization in energy markets Benefits of Cogeneration (CHP)
  15. 15. Energy Efficiency Opportunities Steam turbine: • Keep condenser vacuum at optimum value • Keep steam temperature and pressure at optimum value • Avoid part load operation and starting & stopping Steam Turbine Cogeneration System
  16. 16. Energy Efficiency Opportunities Gas Turbine Cogeneration System Gas turbine – manage the following parameters: • Gas temperature and pressure • Part load operation and starting & stopping • Temperature of hot gas and exhaust gas • Mass flow through gas turbine • Air pressure