Have you been wondering how your refrigerator works? Here is a simple but comprehensive article that explains the working principle of the refrigerator.
It's natural for heat to flow in the direction of decreasing temperature that is from Higher to lower. But think of the reverse [Heat flowing from a lower temperature body to a higher one]. It's not magic, it's the principle of your refrigerator.
Refrigerator is one invention that has certainly changed the way we live. It has made it possible for everyone to preserve food for days. The cold temperature inside the refrigerator slows down the bacterial growth in food and thus preserves the food for longer. But how exactly does the inside of the inside of the refrigerator remain cold?
In order to keep food fresh, a low temperature must be maintained inside the refrigerator inorder reduce the reproduction rate of harmful bacteria. A refrigerator works to transfer heat from inside to outside, which is why it feels warm if you put your hand on the back side of fridge near the metal pipes - you'll find out how that works soon....
Before we go into the working principle, first I want to introduce the major component of the refrigerator
1.COMPRESSOR: This is the heart of the refrigerator. It helps to circulate the refrigerant (fluid) through the system. The compressor constricts the refrigerant vapor, raising its pressure, and pushes it into the coils on the outside of the refrigerator.
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2.CONDENSER: The condenser is found visibly at the back of the refrigerator, it cools down the liquid( The heat of the refrigerant is transfer to the surrounding air through the condenser.), as the name implies it condenses the refrigerant from gas to liquid.
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3.EVAPORATOR:The evaporator is located inside a refrigerator(you may not see it) and is the part that makes the items in the refrigerator cold. It collects heat from the refrigerator space to evaporate the liquid refrigerant from the condenser, it cools the area around it, producing the proper environment for storing food.
4.CAPILLARY TUBES: The capillary tube is a thin piece of tubing that serves as an expansion valve. The liquid refrigerant is routed through the capillary tube and sprayed into the low-pressure environment of the evaporator.
5.THERMOSTAT :The thermostat controls the cooling process by monitoring the temperature and then switching the compressor on and off. When the sensor senses that it's cold enough inside a refrigerator, it turns off the compressor. If it senses too much heat, it switches the compressor on and begins the cooling process again. That why sometimes your refrigerator stops and then pick up by itself.
OPERATING PRINCIPLE
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If you apply some quantity of methylated spirit on your skin, you will observe a cool sensation as the spirit evaporate. That's how the refrigerator works. Just like the methylated spirit the refrigerant changes from gas to liquid in the condenser and this liquid is sent to the evaporator through the expansion valve(to reduce the temperature and pressure further). As it gets to the evaporator which is located inside your refrigerator space, just like your skin, Heat is transferred from the refrigerator space via the evaporator to evaporate the liquid refrigerant to gas. This cycle continues and it's called the refrigeration cycle.
I believe now we know what's happening inside the refrigerator.
I hope you enjoyed this write up. My next post is going to be on a special kind of refrigerator called THE SEABECK REFRIGERATOR. Please anticipate..........
Reference :
- Thermodynamics and engineering approach by cengel
- Wikipedia
- Howstuffswork.com