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Rankine Cycle Thermal Efficiency Calculator

The Rankine cycle is the fundamental thermodynamic operating cycle used by modern thermal, nuclear, and biomass power plants.

Superheated steam enthalpy entering the turbine (kJ/kg).

Steam enthalpy exiting turbine into condenser (kJ/kg).

Saturated liquid water enthalpy exiting the condenser.

Compressed liquid water enthalpy exiting the feed pump into boiler.

Calculated Result
38.11 %

Rankine Thermal Efficiency (η_th)

Thermal Efficiency (η_th)

38.11 %

Net Specific Work Output

1224 kJ/kg

Turbine Work (W_t)

1230 kJ/kg

Feed Pump Work (W_p)

6 kJ/kg

Heat Input (Q_in)

3212 kJ/kg

Heat Rate

8,954 Btu/kWh

Calculation Breakdown

  1. Turbine WorkW_t = h₁ - h₂ = 3410 - 2180 = 1230 kJ/kg
  2. Pump WorkW_p = h₄ - h₃ = 198 - 192 = 6 kJ/kg
  3. Net WorkW_net = W_t - W_p = 1224 kJ/kg
  4. Thermal Efficiencyη = (W_net / Q_in) × 100 = 38.11%

Work and Heat Balances in Rankine Cycle (kJ/kg)

Interactive visualization based on your current inputs

kJ/kg
0.08031.6k2.4k3.2kTurbine Work (Wt)Net Work (Wnet)Boiler Input (Qin)Rejected Heat (Qout)Pump Work (Wp)Thermodynamic ParameterEnthalpy (kJ/kg)

What Is the Rankine Cycle Thermal Efficiency Calculator?

The Rankine cycle is a closed-loop thermodynamic cycle converting heat into mechanical shaft work using phase change of water/steam.

How Does the Rankine Cycle Thermal Efficiency Calculator Work?

Liquid water is pumped into a boiler, vaporized into high-pressure steam, expanded across a turbine to drive a generator, and condensed back into liquid.

Rankine Cycle Thermal Efficiency Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

\eta_{\text{th}} = \frac{W_{\text{net}}}{Q_{\text{in}}} = \frac{(h_1 - h_2) - (h_4 - h_3)}{h_1 - h_4}

Thermal efficiency is net work (turbine work minus feed pump work) divided by boiler heat input.

How to Use the Rankine Cycle Thermal Efficiency Calculator

  1. Enter steam enthalpy at the turbine inlet h₁.
  2. Specify turbine exhaust enthalpy h₂.
  3. Input condenser exit liquid enthalpy h₃.
  4. Provide boiler feedwater inlet enthalpy h₄.

Step-by-Step Example Calculation

Superheated Steam Power Plant

Input Values:

turbineInletEnthalpyH1:3410.0
turbineExitEnthalpyH2:2180.0
condenserExitEnthalpyH3:192.0
boilerInletEnthalpyH4:198.0
Worked Steps: Expanding steam from 3410 to 2180 kJ/kg generates 1224 kJ/kg of net work with 38.11% thermal efficiency and a heat rate of 8953 Btu/kWh.

Understanding Your Result

Thermal Efficiency: Percentage of input heat converted into net work.

Net Work Output: Usable electrical generation energy in kJ/kg.

Heat Rate: Fuel heat required per kilowatt-hour generated (Btu/kWh).

Factors That Affect the Result

  • Boiler steam pressure and superheat temperature, and condenser vacuum temperature.

When Should You Use This Calculator?

  • Coal, natural gas combined cycle, nuclear reactor, and concentrated solar thermal power plant design.

Assumptions & Limitations

  • Assumes steady-state flow and isentropic turbomachinery without parasitic reheat losses.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Standard ASME / IAPWS thermodynamic formulation.

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