Thermodynamic State Variable Calculator

Work Done: - J

Heat Transfer: - J

Change in Internal Energy: - J

Entropy Change: - J/K

Understanding Thermodynamic State Variables

Fundamental Concepts

Thermodynamic state variables describe the equilibrium state of a system.

Ideal Gas Law: PV = nRT

First Law: ΔU = Q - W

Second Law: ΔS ≥ 0

where:

  • P = Pressure
  • V = Volume
  • T = Temperature
  • n = Number of moles
  • R = Gas constant
  • U = Internal energy
  • Q = Heat transfer
  • W = Work done
  • S = Entropy

Thermodynamic Processes

  • Isothermal: T = constant
  • Isobaric: P = constant
  • Isochoric: V = constant
  • Adiabatic: Q = 0
  • Cyclic: Initial = Final state
  • Reversible: Ideal process
  • Irreversible: Real process
  • Quasi-static: Infinitely slow
  • Polytropic: PVⁿ = constant
  • Free Expansion: No work done
  • Phase Changes
  • Heat Engines

Applications and Analysis

Heat Engines

Carnot cycle efficiency

Power Plants

Rankine cycle

Refrigeration

Vapor compression

Gas Turbines

Brayton cycle

Chemical Reactions

Enthalpy changes

Phase Transitions

Latent heat