The concept of the refrigerator

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How would have life been without refrigerators, as there are very few things that can soothe our parched throat the same way a glass of chilled water does. Although the ancient people had techniques which they used but it was certainly not as easy as opening a door at home and taking out a bottle of ice-cold water.
Even when they could lay hands on cold water, they certainly didn't have anything that makes their food stay fresh for days.
luckily we have this little thing that does all this for us. @The Refrigerator 😊😊

In this article, we will be looking at the science of the refrigerator, it's parts and their working principle.

The term refrigeration is simply the process of removing heat from a lower temperature reservoir and transferring same to a high temperature reservoir.

I, t's working principle is simply passing a colder liquid continuously around the object that is to be refrigerated. This process is only achievable with the help of this component:

1. compressor

2. throttling device

3. condenser

4. evaporator

The Throttling device

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This is a device that dissipates pressure energy by irreversibly converting it into thermal energy.
The throttling device obstruct the flow, thereby causing drastic reduction in pressure. due to this reduction in pressure the boiling point of the refrigerant is reduced and it starts to evaporate.
This heat required for evaporation comes from the restaurant itself, so it loses heat and it's temperature reduces.

N/B

That it is wrong to say that the throttling is a
process . We know only the end points of throttling, that is, the states before and after throttling. We don’t know the states in between, since this is a highly irreversible change. So it would be correct to call throttling a phenomenon rather than a process.
this device is responsible for the production of the cold liquid.

The Evaporator

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This is a device used to turn the liquid form of a chemical substance such as water into its gaseous-form/vapor. The liquid is evaporated, or vaporized, into a gas form of the targeted substance in that process.
This cold liquid is passed over the body that has to be cooled. As a result, the refrigerant absorbs the heat. During the heat absorption process, the refrigerant further evaporates and transforms into pure vapor.

N/B: ***

Since the evaporator is cooling the surrounding air, it is common that water will condense on it, forming frost. The frost will act as an insulator between the evaporator heat exchanger and the surrounding air. Thus it will reduce the effectiveness of the heat removal process. Frequent removal of frost is required to enhance the heat transfer.

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The compressor

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This is a machine or part of a machine that
squeezes gas or air and makes it take up less space.
The compressor is responsible for returning the pressure back to its initial level. But since it is compressing gas, along with pressure, temperature will also be increased. This is unavoidable.
outside from increasing the pressure, the compressor also helps maintain the flow in the refrigerant circuit.
You might have noticed that, your household refrigerator consumes a lots of electricity compared to the other devices. Compressing the gas and raising pressure is a highly energy intensive affair. This is the reason why the refrigerator consumes a lot of electricity.

The condenser

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This is an equipment used for reducing gases to their liquid or solid form by the abstraction of heat.
This heat exchanger is fitted outside the refrigerator, and the refrigerant temperature is higher than atmospheric temperature. So heat will dissipate to the surroundings. The vapor will be condensed to liquid, and the temperature will return to a normal level.

how it really works

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The process of heat and power transfer happening in a vapor compression refrigeration circuit is shown above.
A simple energy balance of the system yields the following relationship.

A term called Coefficient of Performance (C.O.P) helps in evaluating the performance of a refrigerator. And to understand this term completely, we need to know what is the input and output of a refrigeration system.
The Input of the refrigerator is the power given to the compressor while the output is the required effect which is the cooling.

So the term C.O.P can easily be defined as output by input and is expressed as,

I believe that this article has help explain the concept of the refrigerator and it's working principles feel free to ask questions and also contribute through comment.

thanks for reading,

until next time,

References

Ref 1, Ref 2, Ref 3

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