Thermodynamic system

Diagram Systems

system boundary2

Thermodynamic system refers to a specific quantity of matter or a region in space chosen for study. The boundaries of the system separate it from the surrounding environment. Systems are classified based on their interactions with the surroundings: isolated systems, closed systems, and open systems. An isolated system does not exchange energy or matter with its surroundings, a closed system exchanges energy but not matter, and an open system exchanges both energy and matter.

Types of Thermodynamic Systems

Isolated Systems

An isolated system is completely sealed from its environment. It does not exchange heat, work, or matter with the surroundings. The total energy and mass within the system remain constant. Examples include an insulated thermos or the universe itself, considered as a thermodynamic system.

Closed Systems

A closed system can exchange energy (as heat or work) but not matter with its environment. Many types of engines and refrigerators operate as closed systems during their cycles.

Open Systems

In an open system, both energy and matter can be exchanged with the surroundings. Biological organisms, such as humans, are examples of open systems, as they take in nutrients and oxygen and expel waste products and carbon dioxide.

Laws of Thermodynamics

Thermodynamic systems are governed by the laws of thermodynamics, which describe the principles of energy transfer within these systems.

• The First Law of Thermodynamics, also known as the law of energy conservation, states that energy cannot be created or destroyed in an isolated system.
• The Second Law of Thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible.
• The Third Law of Thermodynamics suggests that as the temperature of a system approaches absolute zero, the entropy of the system approaches a minimum value.

Applications

Thermodynamic systems are fundamental to the study and application of energy engineering, including power generation, refrigeration, and air conditioning systems. Understanding these systems is also crucial in fields such as chemical engineering, mechanical engineering, and environmental science.

See Also

• Entropy
• Thermodynamic cycle
• Heat engine
• Refrigerator