Most gas turbines are internal combustion engines but it is also possible to manufacture an external combustion gas turbine which is, effectively, a turbine version of a hot air engine. Those systems are usually indicated as EFGT (Externally Fired Gas Turbine) or IFGT (Indirectly Fired Gas Turbine).
External combustion has been used for the purpose of using pulverized coal or finely ground biomass (such as sawdust) as a fuel. In the indirect system, a heat exchanger is used and only clean air with no combustion products travels through the power turbine. The thermal efficiency is lower in the indirect type of external combustion; however, the turbine blades are not subjected to combustion products and much lower quality (and therefore cheaper) fuels are able to be used.
Closed-cycle gas turbines based on helium or supercritical carbon dioxide also hold promise for use with future high temperature solar and nuclear power generation.
Read more about this topic: Gas Turbine
Other articles related to "external combustion, combustion, external":
... An external combustion engine (EC engine) is a heat engine where an internal working fluid is heated by combustion of an external source, through the ... "Combustion" refers to burning fuel with an oxidizer, to supply the heat ... heat from other sources such as nuclear, solar, geothermal or exothermic reactions not involving combustion but are not then strictly classed as external combustion engines, but as external ...
... steam calliope, but the difference is that in the calliope the combustion is external to the resonant cavity, whereas the pyrophone is an internal combustion instrument ... The difference initially seems insignificant, but external combustion is what gives the calliope its staccatto ... Operating under the constant pressures of an external combustion chamber, the calliope merely directs exhaust ...
Famous quotes containing the words combustion and/or external:
“The night has been unruly. Where we lay,
Our chimneys were blown down, and, as they say,
Lamentings heard i th air, strange screams of death,
And prophesying with accents terrible
Of dire combustion and confused events,
New-hatched to the woeful time.”
—William Shakespeare (15641616)
“The manifestation of poetry in external life is formal perfection. True sentiment grows within, and art must represent internal phenomena externally.”
—Franz Grillparzer (17911872)