Gas Turbine Handbook : Principles and Practices

Microturbines 169
Chapter 11
Microturbines
MICROTURBINES
The size of a gas turbine, or its name (heavy industrial, aeroderivative,
mini-turbine, microturbine) does not change the
fact that all gas turbines are mass flow machines and are
thermodynamically the same. To maximize the output power from a
gas turbine the tips of its rotors have to turn close to the speed of
sound. Therefore, the smaller the diameter of the turbine the higher
the speed required to maximize the power output. Aero-derivative
and heavy industrial gas turbines generally fall in the 1 megawatt
and up range.
Table 11-1.
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Type α
Power Range
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Heavy Industrial & Aero-derivative 1000 kW and up
Mini-Turbine
500 kW – 1000 kW
Microturbine
20 kW – 500 kW
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α See Appendix A-1 Gas Turbine Manufacturers and A-2 Microturbine Manufacturers
The capability of the materials used in a gas turbine is the
only limitation it faces. The aero-derivative produces almost as much
power as the largest heavy industrial machine. It accomplishes this
by running at high rotor speeds (up to 20,000 rpm) to provide the
required mass flow.
Microturbines are high-speed (up to approximately 100,000
rpm) combustion gas turbines with outputs from a low of 20 kW
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