When you have been to the gym or it’s a really hot day, indulging in an ice-cold drink can be heaven. Thanks to the invention of the refrigerator, most of us only have to step into the kitchen to experience this. We take having access to a chiller for granted, but until relatively recently only the very rich owned one.
Food preservation was a tough job before refrigeration. Foods could be salted or, in the winter months, buried outside in the cold. It was hard work keeping the cupboards stocked and preventing what food you did have from spoiling before it was eaten.
William Cullen of the University of Glasgow demonstrated artificial refrigeration for the first time in 1748. It wasn’t until 1805, however, that the first refrigeration machine was designed by Oliver Evans, an American inventor. 1834 saw the first practical refrigeration unit built by Jacob Perkins.
The invention of affordable refrigeration therefore changed lives for the better. As well as enabling us to keep food fresher for longer, it helps us to more easily avoid illnesses. Gone are the days of having to keep a cow in the back yard to supply milk daily – you can now buy a four-pint container of milk and expect it to last a week or more in the fridge without turning sour.
The most obvious reason is, of course, to keep food chilled. Cold food stays fresher for longer, as the bacteria (present in all food) grow more slowly in colder temperatures. One example of this is milk. If left at room temperature, milk will go off in just two to three hours (more quickly in the sun or in very warm weather). Place it in a refrigerator and it will stay fresh significantly longer. You can even go a step further and freeze the milk, which will ensure it remains fresh for months. Today, freezing and refrigeration have become the most frequently used ways to preserve food.
The choice of fridges, freezers and bottle coolers available on the market today is vast. You can browse a huge selection at Fridge Freezer Direct and other online stores.
The Cycle of Refrigeration
Five basic components make up the refrigeration cycle:
- Fluid refrigerant
- A compressor
- Condenser coils
- Evaporator coils
- An expansion device
1. The compressor works to control refrigerant flow. It raises the pressure of the refrigerant gas by constricting it. This in turn pushes the gas into the external coils.
2. Once the gas is in the coils it meets the colder air in the kitchen and reverts to a liquid.
3. Now at high pressure, the liquid cools and flows into the internal coils of the refrigerator.
4. The cold refrigerant then absorbs the heat within the refrigerator, reducing the temperature.
5. Finally, the refrigerant evaporates and flows back into the compressor, where the cycle begins again.