<span id="2s198"></span>

1. <em id="2s198"></em>

## Friday, February 14, 2020

### Difference between 'Thermodynamics' and 'Heat Transfer'

Thermodynamics and Heat Transfer both are part of thermal engineering and each one has its own meaning and importance. Both deal with heat and energy then, one might ask, what is the real difference between the two subjects? i.e. Thermodynamics and Heat Transfer

"Thermodynamics" deals with the amount of energy in the form of heat or work during a process and only considers the end states in equilibrium. It will not give information about how long it will take to reach to the final state in equilibrium. While

"Heat Transfer" deals with the rate of energy transfer thus, it gives an idea of how long a heat transfer will occur? Heat transfer deals with time and nonequilibrium phenomena. Heat can only transfer when there is a temperature gradient that exists in a body and which is an indication of nonequilibrium phenomena.

In short, Thermodynamics gives "Why"  a process will occur and Heat Transfer will tell, "How" a process will occur when there is a concern about the transfer of heat.

To support all these arguments, Thermodynamics uses the following laws,

• Zeroth Law of Thermodynamics (defines temperature)
• The first law of Thermodynamics (defines internal energy)
• Second Law of Thermodynamics (defines entropy)
• Third Law of Thermodynamics (limits the lowest temperature attainable)

While Heat Transfer uses,

• Fourier's Law (Heat conduction)
• Newtons Law of Cooling (Heat convection)
• Stephan Boltzman's Law (Thermal Radiation)