The refrigerator, one of the wonders of modern life!
The refrigerator is one of the wonders of modern life that has completely changed our lives. Almost every home has a refrigerator in its kitchen. It keeps things cold.

Purpose of the refrigerator
The fundamental reason for having a refrigerator is to keep food cold. Cold temperatures help food stay fresher for longer. The basic idea behind refrigeration is to slow down the activity of bacteria (which all foods contain) so that the bacteria have more time to spoil the food.
For example, bacteria will spoil milk in two to three hours if it is left in the kitchen at room temperature. However, by lowering the temperature of the milk, it will stay fresh for a week or two - the cold temperature inside the refrigerator reduces the activity of bacteria, By freezing milk.
You can completely stop the bacteria and the milk can be usable for months (until freezer burn starts to spoil the milk in a non-bacterial way).
Refrigeration and freezing are the two most common forms of food preservation used today.

Refrigerator construction
The basic idea behind a refrigerator is very simple: it uses the evaporation of a liquid to absorb heat. You probably know that when water hits your skin, you feel cool. When the water evaporates, it absorbs heat and creates that cool feeling.
The liquid used in the refrigerator evaporates at an extremely low temperature, so it can create the temperature needed for freezing inside the refrigerator.
There are five main parts of any refrigerator:
- Compressor
- Heat exchanger tubes - a set of serpentine or coiled tubes, outside the unit
- Expansion valve
- Heat Exchanger Tubes - A set of serpentine or coiled tubes inside.
- Refrigerant - The liquid that evaporates in a refrigerator to create cold temperatures.
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