# Understanding Thermodynamics 3 Systems & Examples [PDF]

Contents

A thermodynamic system is defined as a quantity of matter or a region in space upon which attention is concentrated in the analysis of a problem. Before proceeding on to the definition of Surrounding, Boundary, the Universe first considers a system as shown in the figure Everything external to the system is called the Surrounding. the system is separated from the surrounding by the System Boundary. This may be either fixed or moving. The system and surrounding together comprise the Universe.

## Types of Thermodynamic Systems

There are three types of thermodynamic systems which are as follows

• Closed System
• Open System
• Isolated System

## Closed system

Mass is fixed. No mass can cross the boundary of the system. This is also called a Control Mass system. Heat energy can be exchanged with its surrounding.

“A closed system is defined as in which the mass is fixed (No mass can cross the boundary of the system) and heat energy can be transferred to its surrounding.”

#### Example

Piston cylinder arrangement without valves. other examples

Putting a lid on the saucepan makes the saucepan a closed system. By putting a lid on the saucepan, the matter can no longer transfer because the lid prevents the matter from entering the saucepan and leaving the saucepan-This example you will understand when you read open system examples. So now Open system,

## Open system

Mass is not fixed. Mass can cross the boundary of the system. This is also called a Control volume system. Heat energy also can be exchanged with its surrounding.

“An open system is defined as in which the mass and heat energy can be transferred to its surrounding.”

#### Example

Boiling soup in an open saucepan on a stove, the energy and matter are transferred to the surroundings through steam, this is an example of an open system.

An air compressor, Turbine.

## Isolated system

Mass is fixed. No mass can cross the boundary of the system. This is also called a Control Mass system. Heat energy also can not be exchanged with its surrounding.

“An isolated system is defined as in which the mass is fixed (No mass can cross the boundary of the system) and as well  heat energy can not be transferred to its surrounding.”

#### Example

A thermos flask (But in reality this system does not exist because the hot water in this can not remains hot forever)

## Purpose of the these systems

• Closed system: The application of a closed system is in the study of thermodynamics and in engineering processes that require controlled environments.
• Open system: The application of an open system is in the study of ecology, biology, and environmental science, as well as in engineering processes that require fluid flow, such as pumps and turbines.
• Isolated system: The application of an isolated system is in the study of thermodynamics and in engineering processes that require precise control over energy transfer, such as in space technology and high-precision manufacturing.

## Conclusion

In conclusion, understanding the different types of thermodynamic systems is crucial in the study of thermodynamics. Closed systems have a fixed mass but can exchange energy with the surroundings, open systems can exchange both mass and energy with the surroundings, and isolated systems cannot exchange either.

Examples of these systems include a piston-cylinder device for closed systems, a boiling water tank for open systems, and the universe as a whole for an isolated system. It is important to properly identify the type of system being analyzed in order to make accurate predictions and calculations in thermodynamics.