What is Thermodynamic System? – Open, Closed & Isolated (With Examples)

Thermodynamic System types (open, closed and isolated system)

These are the Thermodynamic System.

  • Open system
  • Closed system and
  • Isolated system
Thermodynamic System, surrounding and boundary

Let me tell you some basics before starting the types of Thermodynamic system.

What do you mean by thermodynamic system?

What do you mean by surrounding or environment?

What do you mean by boundary?

What is universe?

Here is the answer.

I’ll explain all these terms using this simple image.

The region which is inside the flask is known as a system.

The region which is outside the flask is known as surrounding.

And the imaginary line which separates the system and surrounding is known as a boundary. 

Now, finally the universe is nothing but a combination of flask as well as its surroundings.

(It is similar like the stars, planets, satellites, etc combining to form a universe)

Now let me give you a proper definition of these terms.

Thermodynamic system: System is defined as a part of the universe which is chosen for thermodynamic study.

Surrounding: The region outside the system is known as surrounding.

Boundary: The actual or imaginary line which separates the system and surrounding is known as boundary (see figure).

Universe: The combination of system and the surroundings together is usually referred to as universe. 

Yes this is simple!!!

Now you are done with the definitions of thermodynamic system, surrounding and universe.

Let’s proceed towards the types of thermodynamic system.

What are the types of thermodynamic system?

There are three main types of system.

1. Open system

2. Closed system

3. Isolated system

Open system

“The system in which heat transfer as well as mass transfer takes place with the surroundings is known as open system.”

thermodynamic open system example in which heat transfer and mass transfer takes place

Have you understood anything from the definition and above image?

If not, don’t worry. I will explain to you in a simple way.

You can see in the above image that the transfer of mass of water takes place through the flask.

Why does this happen?

Because the flask is open. Right?

Also the heat transfer is taking place through this system (flask).

Thus a system in which mass transfer as well as heat transfer takes place with the surroundings is known as open system.

Closed system

“The system in which only heat energy is exchanged with the surroundings is known as closed system.”

thermodynamic closed system example in which heat transfer takes place and mass transfer does not takes place

Now this is simple one.

If you have not understood anything from the image, read his below explanation.

You can see in the above image that the flask is closed.

As the flask is closed, there will be no mass transfer.

But, the heat can be transferred through the walls of the flask.

Thus the system in which only heat energy is exchanged with the surroundings is known as closed system.

Isolated system

thermodynamic isolated system example in which neither mass heat transfer nor mass transfer takes place

In this type of thermodynamic system, neither mass transfer takes place nor heat transfer takes place.

You can see in the above image that the flask is isolated using a non conducting material. Because of this, the heat transfer will not take place. Also the flask is closed, so there will be no mass transfer. 

Such a system is known as isolated system.

You might have observed that the hot coffee remains hot and cold coffee remains cold in the thermos flask. 

So the thermos flask is a very good example of isolated system.

Let me summarize the thermodynamic system in a single image and a table for better comparison.

Summary

types of thermodynamics system
Open systemClosed systemIsolated system
Mass transfer (yes)Mass transfer (no)Mass transfer (no)
Heat transfer (yes)Heat transfer (yes)Heat transfer (no)

I hope you have understood the concept of thermodynamic system and surrounding. If you have any queries, feel free to comment below in the comment section.

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