Thermodynamics is based on four fundamental principles known as the laws of thermodynamics:
1. First Law of Thermodynamics: Known as the law of energy conservation, it states that energy cannot be created or destroyed, only transformed from one form to another. In engineering, this concept enables the calculation of energy system efficiency.
2. Second Law of Thermodynamics: This law states that in any energy transfer or transformation process, there is a tendency for entropy, or disorder, in the system to increase. This means no system can operate at 100% efficiency, as there is always an energy loss in the form of unusable heat.
3. Third Law of Thermodynamics: This law relates to the entropy of a system as it approaches absolute zero. It helps define the behavior of materials at extremely low temperatures.
4. Zeroth Law of Thermodynamics: Defines thermal equilibrium between systems. If two systems are in thermal equilibrium with a third, they are also in equilibrium with each other. This concept is foundational for using thermometers and other temperature measurement instruments.
These principles help understand how energy systems function and how to optimize them for various applications.