■ Temperature Is How Hot Something Is
First, temperature.
This is relatively easy to picture.
For example,
● 20°C
● 40°C
● 100°C
In other words, temperature is an indicator of how hot something is.
■ Heat Is Energy
Heat, on the other hand, is energy.
More precisely, it is energy that moves due to a temperature difference.
■ It Is Easy to Understand with a Cup of Hot Water
For example,
● A small cup of 100°C hot water
● A large bath of 40°C hot water
Which one holds more thermal energy?
In fact, in many cases, the bath has overwhelmingly more thermal energy.
In other words, being high in temperature and having a lot of thermal energy are different things.
■ In the AI Era, Thermal Energy Is Becoming Enormous
This is extremely important.
In AI data centers, large numbers of GPUs are lined up.
As a result, not just the temperature of each unit but the total amount of thermal energy in the entire system becomes enormous.
In other words, in the future, what will matter is not only how hot it is,
but how enormous an amount of thermal energy you handle.
■ Why Does Heat Move?
Heat basically has the property of moving from high temperature to low temperature.
For example,
● Hot coffee cools down
● Ice melts
● Heat moves from a CPU to a heat sink
In other words, heat can also be described as a phenomenon in which energy tries to move.
■ Heat Problems Are Problems of Heat Not Escaping
What matters here is not generating heat itself.
The real problem is heat not escaping.
For example, as
● Miniaturization
● Higher density
● Stacking
● Sealing
advance, exits for heat decrease.
Then
● Temperature rise
● Reduced performance
● Degradation
● Failure
occur.
In other words, heat problems can also be described as a thermal energy traffic jam problem.
■ Looking Only at Temperature Leads to Mistakes
What often happens on the shop floor is looking only at temperature.
In reality, however,
● Heat capacity
● Heat flux
● Heat density
● Heat dissipation paths
are also important.
In other words, you cannot see the real heat problem just by knowing how many degrees it is.
■ Take Smartphones, for Example
Smartphones can feel hot to the touch.
In reality, however, various factors are involved, such as
● Where heat is generated
● Heat spreading
● Surface temperature
● Contact with the human body
● Heat dissipation paths
In other words, you cannot simply say that high temperature = bad.
■ In Semiconductors, Localized High Temperatures Are Dangerous
In AI semiconductors and similar devices, only one part may become extremely hot.
This is called a hot spot.
In other words, what matters is not the overall temperature but where heat is concentrated.
■ In EVs, the Amount of Heat Is Enormous
EVs carry large batteries.
In other words, they hold enormous thermal energy.
What matters here is not only how much heat is generated,
but how safely heat can be released.
■ In Wearable Devices, the Sense of Temperature Also Matters
In wearable devices, how people feel changes depending on
● Surface temperature
● Contact time
● Localized heat generation
In other words, for the human body, how humans feel it also becomes a thermal design condition.
■ The Researcher's Perspective: Heat Problems Are Energy Control Problems
In research and development, people consider
● Thermal conductivity
● Heat capacity
● Heat spreading
● Heat dissipation paths
● Heat density
In other words, heat problems are also a question of how to control energy.
■ The Shop-Floor Perspective: Heat Changes Greatly with Contact
On the actual shop floor, the flow of heat changes greatly due to
● Lifting
● Air layers
● Steps
● Uneven contact
In other words, good materials alone do not make a good thermal design.
■ Heat Problems Are Decided by the Process
What truly matters is
● How to process
● How to apply
● How to make contact
● How to mass-produce
In other words, thermal management is determined not only by material performance,
but by making the process work.
■ What Matters from OTIS's Perspective
From OTIS’s perspective, what matters in heat problems includes
● Microfabrication
● Contact stability
● High-precision lamination
● Thin-film processing
● Contact between dissimilar materials
● Volume production stability
In other words, OTIS is committed to processes that make heat flow work.
■ What OTIS Can Do
At OTIS, through
● High-precision die-cutting
● Microfabrication
● High-precision lamination
● Processing of thermal management materials
● Stacking of irregular shapes
● Support for automated supply
we may be able to contribute to making the final contact conditions for heat work in volume production.
■ Outside OTIS's Expertise
On the other hand, OTIS is not a company that specializes in
● Heat-generating device design
● Semiconductor circuit design
● AI algorithm development
● Power generation system development
However, in the area of making heat work in volume production processes, we may be able to play an important role.
■ Summary
“Hot” alone does not reveal the real heat problem
Temperature is how hot something is.
Heat, on the other hand, is energy that moves.
In other words, heat problems are also a question of how to release and control thermal energy.
And in future industries, what will matter more and more is not only how high-performance something is,
but how much enormous thermal energy can be made to work.
Column Supervisor: Koji Kakumoto (President, OTIS Co., Ltd.)
After studying abroad and working in planning and development at a trading company, he joined OTIS Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as President, working to drive business growth and strengthen the organization.
This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.
