CHP (Combined heat and power) is a specific form of distributed generation (DG), which refers to the strategic placement of electric power generating units. CHP enhances the advantages of DG by the simultaneous production of useful thermal and power output, thereby increasing the overall efficiency.
Summary of CHP Technologies:
- Gas turbines: gas turbines are typically available in sizes ranging from 500kW to 250MW and can operate on a variety of fuels such as natural gas, synthetic gas, landfill gas and fuel oils.
- Microturbines: which are small electricity generators. Microturbines use the fuel to create high-speed rotation that turns an electrical generator to produce electricity. In CHP operation, a heat exchanger referred to as the exhaust gas heat exchanger, transfers thermal energy from the microturbine exhaust to a hot water system HWS. Available models range in sizes from 30kW to 250kW.
- Reciprocating engines: spark ignition (SI) and compression ignition (CI) are the most common. SI engines use spark plugs with a high-intensity spark of timed duration to ignite a compressed fuel-air mixture within the cylinder. SI engines are available in sizes up to 5MW. Diesel engines, also called CI engines, are among the most efficient simple-cycle power generation options in the market. Reciprocating engines start quickly, follow load well, have good part-load efficiencies, and generally have high reliabilities.
- Steam turbines: that generate electricity from the heat produced in a boiler. The energy produced in the boiler is transferred to the turbine through high-pressure steam that in turn powers the turbine and generator. The capacity of commercially available steam turbine typically ranges between 50kW to over 250MW.
- Fuel cells: use an electrochemical or battery-like process to convert the chemical energy of hydrogen into hot water and electricity. There are currently five types of fuel cells under development. These include phosphoric acid (PAFC), proton exchange membrane (PEMFC), molten carbonate (MCFC), solid oxide (SOFC), and alkaline (AFC).
No comments:
Post a Comment