冷却技術の歴史
Hello everyone, welcome to SCIEN-SPOT, this podcast that shines spotlights on the latest
scientific technology from Japan.
Your host is REN from SCIEN-TALK.
But this week, I'm thinking about doing a special cooling week, where we'll focus
entirely on all things cooling.
It's going to be another hot summer, after all.
Even though it's probably not as bad as Japan, London gets pretty warm too.
So over 5 sessions this week, I'll be talking about the history of refrigeration, the evolution
of refrigerants, magnetic cooling, acoustic cooling, and solid-state cooling.
So today's topic is about the history of a refrigerator.
So today, we can get fresh ingredients anytime, anywhere, as a matter of course.
This benefit is thanks to refrigerators and freezers.
Just about 100 years ago, people struggled immensely to preserve their food.
And in the era before electricity, how did people prevent food from spoiling?
First, the most primitive yet logical method was to utilize natural cold temperatures.
For example, do you know about Japan's Himuro, or ice houses?
These were facilities where snow and ice were stored in whole dugs in mountains or in huts
covered with roofs and preserved until summer.
During the Heian period, they were used to store ice presented to the imperial court,
食料保存の技術
and in the Edo period, ice cellars appeared among the common people, spreading a culture
of enjoying natural ice in summer.
It's somewhat similar to how modern data centers use cold air underground to cool their servers.
However, relying solely on natural cold has its limits.
So people devised various preservation techniques, and salting, drying, smoking, fermentation.
These were all the wisdom of our ancestors to suppress microbial activity and prevent
food spoilage.
These techniques not only extended the life of food, but also had an immeasurable impact
on society.
They reduced the risk of farming by allowing people to secure food regardless of season
or weather.
Furthermore, they enabled food transportation to distant regions, leading to the fusion
of regional food cultures and the consumption of off-season ingredients, dramatically enriching
diets.
Importantly, they also improved public health by reducing the risk of food poisoning, which
was a major cause of high infant mortality rates in summers, before refrigerators became
widespread.
From the era of natural wisdom of ingenuity, humanity took another step forward.
People began to search for ways to cool more freely and efficiently.
This is where the story of scientists' passion and challenge begins.
冷却技術の基礎
The foundation of artificial cooling technology was laid by thermodynamics, a scientific field
that developed between the 18th and 19th centuries.
As the principles of how heat moves and how energy transforms were elucidated, the possibility
of lowering temperature by extracting heat, in other words, cooling, emerged.
A pivotal figure in this field was the American inventor Oliver Evans.
In 1805, he proposed the concept of the vapor-compression-refrigeration cycle, which obtained a cooling effect by evaporating
ether.
This is the very same basic principle used in today's refrigerators.
However, the technology of the time made it difficult to put his idea into practice.
And taking over Evans' idea, the British engineer Jacob Perkins actually built a machine.
In 1834, he obtained a patent for a vapor-compression-refrigerator using ether.
This is considered the world's first artificial ice-making machine and the prototype of modern
refrigerators.
However, these early machines faced challenges such as refrigerant leakage and the inefficiency
preventing commercial success.
And through the efforts of the setback of these pioneers, it was the German engineer
Karl von Linde who elaborated artificial cooling technology to an industrial level.
人工冷却技術の発展
In 1876, he developed a more efficient and safer ammonia vapor-compression-refrigerator.
Ammonia was relatively inexpensive and readily available at the time, and its cooling efficiency
was high, so his invention quickly spread in industries like breweries or meat processing plants.
If the previous trials and errors were just isolated dots, Linde's invention connected
those dots into a line, paving the way for practical application.
This advanced food transportation over long distances and greatly contributes to the stabilization
of food supply.
What's even more interesting is that the history of refrigeration also features the
unexpected figures of Albert Einstein and physicist Leo Szilard.
In 1926, they obtained a patent for the Einstein-Szilard refrigerator, which operated without electricity.
This was an innovative absorption refrigerator that cooled by circulating gas and liquid.
It had advantages like usability in areas without electricity and fewer moving parts,
making it less prone to breakdown.
However, this refrigerator ultimately did not reach commercialization.
The main reasons were its lower cooling efficiency and a larger size compared to existing electric
refrigerators at the time, and above all, the overwhelming superiority of electric refrigerators
using CFCs as refrigerants, so their idea through truly brilliant perhaps couldn't
冷却技術の誕生
ride the wave of existing technological evolution.
The birth of artificial cooling technology was truly the culmination of scientists'
passion and countless trials and errors.
Without their challenges, our diets would be completely different today.
The story of refrigerators is not just the evolution of home appliances, it's a grand
narrative of humanity's struggle to protect and enrich the fundamental essence of life,
food, profoundly transforming society as a whole.
Thank you for listening to the Science Spot today.
This story begins from today, and in this week, I will present the many episodes for
the refrigerators.
So this podcast Science Spot is broadcast daily on weekday morning in both Japanese
and English.
I'd love for you to listen to the podcast and post your thoughts with the hashtag Science
Spot.
See you next time.
