Food & agriculture · 1834
Mechanical refrigeration
Jacob Perkins patented a machine that made ice by compressing and expanding a vapour.
Perkins' 1834 vapour-compression cycle is still the basis of nearly every fridge and air conditioner. Practical plants by James Harrison and Carl von Linde followed, making it possible to store and ship perishable food at scale.
What it built on 1
What it led to 5
Related measurements
The dashed line marks when it first worked.
US households with a refrigerator Latest: 98 % of households (2017) Source: Our World in Data