Cold Storage Extends Shelf Life
August 18, 2020
There’s a Keystone in every great invention.
As we hit the height of summer heat, with record breaking temperatures across the globe, it is easy to take for granted all of the creature comforts we have today. From electricity that offers air conditioning, to indoor plumbing that provides running water, modern technology has paved the way for many of us to live more comfortable lifestyles. Another comfort that should not be overlooked is the food supply chain, and more specifically our ability to transport and store fresh produce, dairy, meats, seafood and more. Refrigerators and freezers are a vital part of this supply chain, whether in trucks during transport, in grocery stores, or in our homes, cold storage systems safely preserve food and beverages to prolong the life of perishable items. According to the U.S. Department of Agriculture, around 30 to 40 percent of the food grown in the United States goes uneaten. This staggering number would be significantly higher without cold storage provided by refrigerator and freezer technologies.
Cold storage has had a profound impact on the development of human culture and the modern world. Cold storage technology has enabled people to migrate into hotter, dryer climates without concern for food spoiling in the heat. Cold storage dates back thousands of years. The first evidence of cold storage was recorded in Syria more than 3,700 years ago. Archeologist and historians have also verified that the ancient Chinese and Persians also harvested ice, which would then be kept in an insulated cellar or ice house and used to preserve food and chill drinks. Ice was stored during the winter months to provide cold storage and preserve food into the warmer parts of the year. Romans, Greeks and ancient Egyptians also stored ice, primarily for cooling drinks in the summer.
Fast forward to 1806, an American entrepreneur Frederic Tudor, who later became known as the Boston Ice King, recognized the value of harvested ice to the average person. This began the ice trade of the 1800’s. Large blocks of ice were cut and transported from New England for sale in the Southern United States down to the Caribbean. Ice houses were instrumental for storage to reduce melting of the ice blocks. This ice trade propagated the use of cold storage in the average person’s home. By 1830, the use of ice boxes for storage was at its height of popularity, and the public was accustomed to storing food in their own homes. This paved the way for electric refrigeration.
In 1755, Professor William Cullen conducted the first experiment to lower the temperature of an object with a refrigerant. Using diethyl ether, Professor Cullen successfully produced a small amount of ice. Three years later, John Hadley and Benjamin Franklin developed a way to cool a thermometer bulb down to -7°C from 18°C, creating ice a quarter of an inch thick around the bulb.
In 1834, American Jacob Perkins, known as the father of the refrigerator, built the first working vapor-compression refrigeration system in a facility in Great Britain. The new closed-cycle device could operate continuously.
The first commercial ice-making machine was invented in 1854. This patented alcohol or ammonia vapor compression refrigeration system was built by James Harrison, a Scottish Australian. He built a mechanical ice-making machine in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Victoria, with the commercial ice-making machine following in 1854. Harrison also introduced commercial vapor-compression refrigeration to breweries and meat packing houses. By 1861, a dozen of these systems were in operation.
In 1913, refrigerators for home use were invented. In 1923 Frigidaire introduced the first self-contained unit. The introduction of Freon in the 1920s expanded the refrigerator market during the 1930s. Home freezers as separate compartments were introduced in 1940. Frozen foods, previously a luxury item, became commonplace.
Other Notable Advancements
- In 1805, American inventor Oliver Evans described a closed vapor-compression refrigeration cycle for the production of ice by ether under vacuum.
- In 1820, British scientist Michael Faraday developed new refrigerants by liquefying ammonia and other gases by using high pressures and low temperatures
- In 1859, the first gas absorption refrigeration system using gaseous ammonia dissolved in water (aqua ammonia) was developed by Ferdinand Carr of France and patented in 1860.
- In 1876, Carl von Linde, an engineering professor at the Technological University Munich in Germany, patented an improved method of liquefying gases. His new process made possible the use of gases such as ammonia (NH3), sulfur dioxide (SO2) and methyl chloride (CH3Cl) as refrigerants and they were widely used for that purpose until the late 1920s.
Modern Cold Storage
Most household refrigerators, refrigerator–freezers and freezers utilize a vapor compression cycle. The main components of this system feature a motor and refrigerant, such as R134a, that is cycled through a compressor, condenser coils, expansion valve, fan, and evaporator, Throughout the cycle, the refrigerant goes through many forms including gas (vapor) and liquid via pressured and unpressured chambers to ultimately cool the box where food and beverages are stored.
Modern domestic refrigerators and freezers are more reliable because the motor and compressor are integrated within a sealed container. This reduces the likelihood for refrigerant leaks or contamination. Externally-coupled refrigeration compressor units, like those used in vehicle air conditioning, eventually leak fluid and lubricant. This ultimately leads to the need for periodic refrigerant recharging and/or compressor failure.
Refrigerator and freezer technologies have progressed far beyond just cold storage. Today’s smart fridge and freezer units feature water & ice dispensers, user control panels & displays, Wi-Fi connectivity, voice recognition & control, and more.
A Longer Shelf Life
Once electric refrigeration came to fruition, cold storage was no longer limited to storing naturally-occurring ice. Ice could be created anywhere, at any time of year. This began an evolution for man-kind, making it possible to transport food across the world and store it safely for much longer periods of time, helping to usher in a modern age that we now take for granted.
A wide range of Keystone products can be found in refrigerator and freezer systems. Much like cold storge keeps food and beverages a longer shelf life, Keystone products give cold storage systems a longer operating life. Keystone products, including LED holders, spacers and lens caps; fuse clips and holders; PCB test points and terminals; spacers and standoffs; panel hardware and PCB plugs, pins, jacks, and sockets are commonly used in refrigeration and freezer systems.