Refrigeration and How it Started

For 1 million years humans have had the ability to burn things, control fire and generate heat. It’s fascinating and in my opinion epic that in just 1620 an inventor/engineer could present themselves as a magician for conjuring cold. In this instance cooling the Great Hall in Westminster Abbey for King James I at the peak of Summer, the ‘magician’ being Cornelis Drebbel.?

Likely, although not confirmed, the process used by Drebbel was adding salt and nitre (potassium nitrate) to chill water, a common feat of alchemists before his time, then allowing air to circulate in the room to cool the space. Given the size of the hall, the scale of the operation must have been large.?

The idea of controlling "cold" hung around for a long period, Francis Bacon had described heat and cold as "nature's two hands". Robert Boyle coined the term frigorific to describe the hypothetical cold matter which people had claimed resulted in cooling. Boyle and others conducted many experiments to debunk these frigorific theories. Nowadays, we refer only to heat energy.

For many more years, cooling was subject to the environment, a whole industry of ice trade existed where ice was harvested from lakes and shipped worldwide. It was only in the 1920’s that true on-demand control over cooling came about with the introduction of the domestic refrigerator.

In Scotland, the first artificial refrigeration system was discovered by Dr. William Cullen and first demonstrated in 1748 at the University of Glasgow. The discovery came about first by noticing that placing a thermometer coated in alcoholic spirit in a vacuum chamber and lowering pressure had a cooling effect.?

Going a step further, Cullen placed a small vessel of Diethyl Ether (a mixture of alcohol, nitre and strong acids) inside of a larger vessel of water and then placed the pair inside of a vacuum chamber. Then some of the air was pumped out of the chamber, lowering the pressure until the Diethyl Ether evaporated at a high rate. The result was that the water had turned to ice! The first controlled refrigeration experiment had been a success.?

This has been my first blog post, maybe more to follow and thinking of calling the blog Refrigucated, hopefully you found it entertaining. Something I want to add to each post is an interactive element, in this instance there’s a google sheet with a plot of pressures and temperatures to explore under what conditions the first refrigeration effect was observed for Diethyl Ether. Follow link via the image below. Also added properties of water and ethanol for reference. Enjoy!

Cheers, Andy

For those interested in reading more history of refrigeration and fun anecdotes, Tom Jackson wrote “Chilled - how refrigeration changed the world and might do so again”