CalculateItToday

Heat Engine Efficiency Calculator

Calculate Heat Engine Properties

System Properties

Results

Enter values above to calculate heat engine efficiency

About Heat Engines & Efficiency

Heat engines convert heat energy into mechanical work by transferring energy from a hot reservoir to a cold reservoir. Efficiency measures how much of the input heat is converted to useful work.

Key Concepts:

  • Efficiency (η): Ratio of work output to heat input
  • Carnot Efficiency: Maximum possible efficiency for a heat engine operating between two temperatures
  • Work Output (W): Useful energy produced by the engine
  • Heat Input (Qin): Energy absorbed from the hot reservoir
  • Heat Output (Qout): Energy expelled to the cold reservoir

Key Formulas:

  • η = W / Qin - Efficiency from work and heat input
  • η = 1 - Qout / Qin - Efficiency from heat input and output
  • ηCarnot = 1 - Tc / Th - Carnot efficiency (T in K)
  • W = Qin - Qout - Work output

Engine Types:

  • Carnot (ideal, reversible)
  • Rankine (steam power plants)
  • Otto (gasoline engines)
  • Diesel (diesel engines)
  • Brayton (jet engines, gas turbines)

Units:

  • Heat/Work: J, kJ, cal, kcal
  • Temperature: K, °C, °F (convert to K for Carnot efficiency)

Applications:

  • Power plants and electricity generation
  • Automotive and aircraft engines
  • Refrigeration and heat pumps (reverse cycle)
  • Thermodynamic cycle analysis