Rankine Cycle Efficiency
Calculate the thermal efficiency of a Rankine cycle, η = (w_turbine − w_pump) ÷ q_boiler × 100%, dividing the net work (turbine work minus pump work) by the heat added in the boiler, all in kJ/kg. The Rankine cycle is the basis of steam power plants: water is pumped, heated and vaporized in the boiler, expands through the turbine producing work, then condenses. The result, in %, measures how much boiler heat becomes useful work; real cycles run 30–45%. Enter the turbine work, the pump work and the boiler heat.
Resultado
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Eficiência do ciclo Rankine
O ciclo Rankine é o ciclo termodinâmico das usinas termelétricas a vapor — a carvão, a óleo, a biomassa ou nucleares. Ele tem quatro etapas: a bomba pressuriza a água líquida; a caldeira aquece e vaporiza essa água a alta pressão; a turbina expande o vapor, produzindo trabalho; e o condensador resfria o vapor de volta a líquido. A eficiência térmica é a razão entre o que se ganha e o que se gasta: η = (w_turbina − w_bomba) ÷ q_caldeira × 100%. O numerador é o trabalho líquido — o trabalho bruto da turbina menos a parcela consumida pela bomba (que é pequena, pois bombear líquido custa pouco). O denominador é o calor fornecido na caldeira. O resultado diz quanto do calor investido virou trabalho aproveitável; o restante é rejeitado no condensador (imposição da segunda lei da termodinâmica). Ciclos reais ficam em 30–45%; superaquecimento, reaquecimento e regeneração elevam esse valor. Informe o trabalho da turbina, o da bomba e o calor da caldeira.
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Steam Turbine Power
Calculate the mechanical power generated by a steam turbine, P = ṁ × (h₁ − h₂), multiplying the steam mass flow (kg/s) by the enthalpy drop between turbine inlet and outlet (kJ/kg). The result, in kW, is the shaft power delivered to the generator, accounting for the expansion of high-pressure, high-temperature steam down to condenser pressure. It is the core calculation in sizing thermal power and cogeneration plants: the larger the enthalpy drop, the more power per kg of steam. Enter the steam flow and the inlet and outlet enthalpies.
Combined Cycle Efficiency
Calculate the efficiency of a gas-steam combined cycle, η_cc = η_gas + η_steam − (η_gas × η_steam ÷ 100), combining the gas turbine efficiency (Brayton, topping) with the steam cycle (Rankine, bottoming) that recovers heat from the exhaust gases. The result, in %, exceeds either cycle alone because the heat rejected by the gas turbine, instead of being wasted, raises steam for a second turbine. This is why modern combined-cycle plants top 60% efficiency, the highest in thermal generation. Enter the gas-cycle and steam-cycle efficiencies (in %).
Back Work Ratio (BWR)
Calculate the back work ratio (BWR) of a power cycle, BWR = w_compressor ÷ w_turbine, dividing the work consumed by the compressor (or pump) by the gross work produced by the turbine. The dimensionless result shows what fraction of turbine work is reinvested to compress the fluid. In gas turbines (Brayton cycle) the BWR is high (0.4–0.6), since compressing gas is costly; in steam Rankine cycles it is tiny (~0.01), since pumping liquid is cheap. A high BWR makes the cycle sensitive to component efficiencies. Enter the compressor work and the turbine work.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.