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How Does Refrigerator Work?

Ever wondered how a refrigerator we see every day, works? We always see so many home appliances in our surroundings and also use it day by day basis. But hardly we give time to think about how it works.

The home appliances we use everyday functions in a very simple-scientific mechanism, we have read in science books in our childhood. We will discuss the refrigerator and its working principle in this article.

We can put the functioning principle of a fridge into 3 easy and basic steps.

  1. 1
    By the power turned on, the refrigerant is passed around the food inside the fridge and, it covers all the areas like the cloud, including the foods at the refrigerator door.
  2. 2
    The refrigerant cloud absorbs the heat from the food items present inside, holding different temperatures.
  3. 3
    The refrigerant cloud transfers the absorbed heat into surroundings where the temperature is relatively cooler.

In our ancient time, people always put an effort to make their food preserved and had drunk chilled water, but those techniques might not have been as easy as the refrigerator works today for us. Let us proceed with the article and see how simple the whole process is.

Working principle of refrigerators:

The refrigerators’ working principle is solely dependent on refrigerant, which takes an active part in preserving your food for an extended period inside your fridge. Refrigerant is liquid coolant or low-temperature liquid which actively remove heat from one region and transfer it to another.

When this liquid is passed through the objects being addressed to be cooled, heat transfer occurs between the object and liquid. The liquid gets evaporated and takes away the heat from the objects in this process.

If you compress a certain volume of gas, it gets heated up & temperature gets increased, and the expansion of gas lets you cool down the temperature of that similar volume. To explain the theory behind the whole procedure, we have some real-life examples.

If you pump-in air inside the tires, the tire gets heated up, and when you spray body-deodorant, you can quickly feel that the deodorant bottle gets cooled down a few degrees of temperature.

The refrigerant gets evaporated and becomes gas, follows the above-explained rules, and gets your food cold inside the refrigerator. A few more parts & devices of the fridge helps to achieve the temperature it is designed to maintain and store foods inside.

Refrigerator Parts and Devices

Refrigeration is a simple process where a few devices inside your fridge play pivotal roles in accomplishing the whole operation. Let us list the parts and accessories.
  1. 1
    Expansion valve
  2. 2
  3. 3
  4. 4
  5. 5

Through all these components, the refrigeration process takes place silently after you place food inside with varying temperatures.

  • Expansion valve: It is a small device attached with a sensor which senses the refrigerant temperature change. It controls the flow of refrigerant or coolant accordingly and sends it to the evaporator. This little device is considered as a flow controller as it expands and contracts to change the flow of the coolant according to the temperature calibration changes.
  • Evaporator: The evaporator consists of finned metal tubes, and it is the prime device to achieve the cold temperature inside your fridge. Materials make the metal tubes are highly conductive on thermal mannerism as to meet maximized heat transfer. The tubes absorb the heat from the food. The heat transfer happens as there is a blowing fan that pushes the inside air towards the evaporator. The liquid coolant gets evaporated while passing through the evaporator due to the collective heat it gets from the blown air.
  • Compressor: A compressor consists of a motor, and it helps sucking in the refrigerant from the evaporator. Then it compresses the gas inside the cylinder it holds by pressurizing, and the gas becomes hot.
  • Condenser: This device stays in the rear of the refrigerator. The condenser consists of metal tubes as well, where the functionality is just the opposite of the evaporator. This is a coiled set of tubes that helps to recollect gaseous coolant into the liquid state. The heat of gaseous refrigerant gets absorbed by the condenser, and the coolant is liquefied from vapor again into the calibrated temperature. The heats get subsequently pushed out with blow of a fan into the surrounding outside the refrigerator.
  • Refrigerant: The refrigerant is the fundamental chemical to achieve refrigeration action.  Refrigerant is referred to as the coolant in common term to consider its state by altering from liquid to vapor and vice versa without losing its chemical value.

CFC was the standard choice as the coolant in the 20th century. In modern refrigerators, refrigerant options become more environment-friendly. The common choices are R-600A, R-290, ammonia, etc. today as coolant.

Functional flow of Refrigeration process: How a refrigerator works

The whole process of refrigeration works in a cycle and loops continuously to keep a steady and cool temperature inside the fridge. The refrigerant stays in a liquid state and passes through the expansion valve in case the valve senses any temperature fluctuation inside.

The liquid passes and gets into the gaseous state on sudden pressure drop as it expands and becomes cold. This cold gas now goes inside the refrigerator cabinet, and in contact with the food items, it absorbs the heat from them.

The foods become cold inside, but the heat in gaseous form stay until that is sucked in by the motor of the compressor. The compressor senses a rise in the temperature of the gas inside and starts sucking it to its cylinder.

The gas gets heat up as it gets sucked and compressed by the pressure inside the cylinder in the molecular form. The hot, high-pressure gas now flows towards condenser coils or radiator pipes, which is in the backside of the refrigerator.

This hot gas soon dissipates heat into the environment and gets cold enough to become liquid again from a vapory gaseous form. The refrigerant liquid flows towards the expansion valves and stays until it senses the temperature fluctuation again.

The whole process then gets repeated every time there is a new food item you put inside the fridge, or you open the refrigerator door.

What are the techniques through which this whole cycle gets repeated?

The refrigerator works in the same principle we described above but a few small techniques/cycles through which the fundamental changes happen in the refrigerant.

French military scientist Sadi Carnot had explained the whole process through a heat engine in the 18th century. We can assume the refrigeration process is just the heat engine which is working in reverse. Let’s look into it.

  • Vapour compression cycle: This cycle is achieved the moment the gas entered into the compressor and gets heated up.
  • Vapour absorption Cycle: This process is active when the compressed high-pressure gas gets into the dissipator or condenser. Unlike getting heated up, it dissipates the extra heat and gets cold enough to get liquidized refrigerant again.
  • Gas cycle: the Gas cycle is active the moment the liquid gets into gaseous form and enters into the refrigerator cabinet and stays unless the vapor absorption cycle gets achieved and finally, the refrigerant gets it liquidized form again.

Classified History of refrigeration:

The refrigeration process has been with the human being at a very early stage when science used to be taken as derogatory, but the scientists are the hot pursuit of discovering and inventing new techniques through technologies every now and then.

In the early 1700 century, refrigeration techniques had begun taking place. In the late 1700 century or early 1800 century, the vapor compression technique for refrigeration had started taking place for commercial use.

To be specific, it was 1834, when it became the first successful invention for commercial ground. In the early 1900(AD. 1913) century, the first refrigerator for home use came into the market as a home appliance.

How important is it to know the refrigeration process?

The knowledge of the refrigeration process certainly has some extreme value towards your daily life. Refrigeration means artificial or synthetic cooling. This process covers not only your refrigerator or fridge but also all those procedures where you are cooling up a space by a machine.

The process or flow chart stays the same, just the device or tools gets varied depending on the volume of the area you want to decrease the temperature.

The process knowledge covers Air conditioner, refrigerator, one ice cream factory process, and many more. It gives you a perspicuous understanding of the pieces of machinery and the brands, even before you buy a fridge or an AC.

More magnanimously, it covers you up when you need a mechanic if your fridge is not cooling correctly, and the mechanic is not available. You can easily follow the process to repair your refrigerator by yourself with the knowledge of the refrigeration technique.