Gas Turbine Heat Rate & Thermal Efficiency Calculator
Compute Lower Heating Value (LHV) heat rate, gross thermal efficiency, pressure ratio, and ambient temperature/altitude derating factors.
Gas Turbine Rating & Ambient Site
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Brayton Cycle Heat Rate & Ambient Sensitivity
Gas turbine performance is rated under ISO standard conditions ($15^\circ\text{C}$, $101.325\text{ kPa}$, $60\%\text{ RH}$). Because a gas turbine compressor is fundamentally a constant-volumetric-flow machine, hot ambient air decreases air density, reducing the total mass flow of oxygen entering the combustor and directly reducing turbine shaft power output.
Heat Rate (HR) Definition
Heat rate represents the thermal energy input required to generate one kilowatt-hour of electrical output: $$\text{Heat Rate} = \frac{3600}{\eta_{th}} \quad [\text{kJ/kWh}] = \frac{3412.14}{\eta_{th}} \quad [\text{BTU/kWh}]$$ A lower heat rate corresponds directly to higher thermal efficiency and lower fuel consumption per megawatt-hour generated.