Thermodynamics In Mechanical Engineering

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Thermodynamics: Mechanical Engineering Principles

Thermodynamics is one of the mechanical engineering principles which describe the foundations for the operation of mechanical systems. To learn more about these principles read this article.

The essence of thermodynamics involves studying energy, how it is transformed and how it can be used through a system. This is mainly focused on:

  • Heat transfer.
  • State changes.
  • Application of heat power in complex systems.

By reading below, you will learn about some of these aspects, which make thermodynamics a very interesting part of mechanical engineering principles.

What is thermodynamics?

Thermodynamics is often defined as “the branch of physics that deals with heat, work, and temperature, and their relation to energy, radiation, and physical properties of matter” (Wikipedia).

This is an accurate definition if we look at the aspects mentioned above. Heat is a form of energy measured in joules, and work is also measured in joules. This means that they are somehow related, a relation that is studied through thermodynamics.

It is also important to highlight that temperature is not the same as heat. Temperature is an indicator of how hot a body or a substance is, and for different bodies, there may be a different need for heat to reach the same temperature.

What is heat transfer?

Detail of a heatsink
Detail of a heatsink

Heat transfer makes reference to this form of energy moving from one body to another due to a temperature differential or a change of phase. Heat transfer is governed by the laws of thermodynamics, and it can happen in three different ways: conduction, convection, and radiation.


This is the form of heat transfer that occurs through matter from the hottest point (heat source) to the coldest. A good example to understand this form of heat transfer is thinking about a teacup. When you touch the cup handle, you feel the heat. The heat has moved from the inside of the cup which is in touch with the heat source (the tea) to the handle through conduction.


Convection in the form of heat transfer that occurs through some kind of fluid when it is flowing. For example, water flowing in a river or air heated in the presence of gravity.

This is one of the most commonly used forms of heat transfer used in mechanical engineering. For example, in heat exchangers mechanisms such as pumps are used to generate the flow while taking advantage of a temperature differential between the fluid and external air.


Here the heat is transferred in the form of energy waves. A good example is a radiation we receive from the UV rays of the sun. All bodies radiate heat to cooler bodies.

The principle of radiation is used by infrared thermography in order to visually analyze changes in temperatures or the thermal performance of machines and other systems.

Final thoughts

There are many applications of thermodynamics, especially heat transfer and thermal cycles in mechanical engineering systems. Therefore, thermodynamics plays an important role in the product development process when trying to innovate in terms of energy generation, reuse and consumption, climatization, and thermal performance improvements.

Of course, to be able to innovate in such areas you need the right tools, the knowledge, and the experience. That’s what we provide at Porticos, skillful application of the engineering sciences to provide actionable results.

Do you need your structure or machine analyzed and tested? Let us help you, contact us now!


  1. Bird, C. Ross. “Mechanical Engineering Principles” – Second Edition. 2012.


IDC Technologies. (2009). Fundamentals of Mechanical Engineering. ISBN: 978-1-921007-07-1


Keywords: thermodynamics, heat transfer.

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