2nd Law of Thermodynamics Calculator

The Second Law of Thermodynamics constrains energy transformation by identifying that energy goes downhill. Entropy (S), produced by all processes, is associated with the loss of ability to do work.

Key Principles

• 100% energy cannot be transformed to work
• Entropy can be produced but never destroyed
• The efficiency of a heat machine depends on the temperature difference between hot and cold reservoirs

Formulas

Heat Engine Efficiency (Carnot Cycle)

η = (Th - Tc) / Th = 1 - Tc / Th

Where:

• η = thermal efficiency
• Th = hot reservoir temperature (K)
• Tc = cold reservoir temperature (K)

Entropy Change

ΔS = ΔH / Ta

Where:

• ΔS = change in entropy (kJ/kg·K)
• ΔH = change in enthalpy or internal energy (kJ/kg)
• Ta = average temperature (K)