National Thermal Engineer Day

National Thermal Engineer Day is observed annually on July 24—and fittingly so, as it falls in one of the hottest months of the year. Thermal energy is all around us. What we perceive as heat is simply the transfer of thermal energy from one object to another. This day honors thermal engineers and their vital role in managing, utilizing, and innovating with heat in our modern world.

History

In ancient times, heat was associated with fire, which many early cultures believed to be mystical. In Western mythology, fire was revered as one of the essential elements of life. At one point, people believed fire came from a special invisible liquid stored in materials—this gave rise to the term “heat capacity.” That theory was discarded in the 18th century when scientists realized heat is a result of internal energy.

English physicist James Prescott Joule is credited with discovering the nature of thermal energy. National Thermal Engineer Day was established by Advanced Thermal Solutions, Inc. (ATS) to raise awareness about the work of thermal engineers and their contribution to fields like mechanical engineering and electronics.

Interesting Facts

• German physicist Julius Robert von Mayer claimed he discovered the principle of thermal energy a year before Joule. However, Joule is more widely credited due to his extensive experimental research.
• Thermal energy is not the same as temperature. A bucket of water and a glass of water can be the same temperature, but the bucket has more thermal energy because of its volume.
• Unlike many other forms of energy, thermal energy is difficult to convert into other types.
• Thermal energy is essential in vehicle heating and cooling systems.
• Energy becomes heat only when it transfers from one object to another—it does not exist as heat until that point.

How to Take Part

Celebrate the thermal engineers in your life and thank them for their essential work. A cold drink would be a thoughtful gesture on a hot day. You can also post on social media to raise awareness about the day, or take some time to learn more about how thermal energy is used in modern inventions and technology.

When is National Thermal Engineer Day in 2025?

National Thermal Engineer Day is observed on July 24 each year.

Observations