How Refrigerator Work
Have you ever wondered how your freezers operate? OR How Refrigerator Work? So, to begin, refrigerators, which have become an indispensable element of every family, work on the basis of some simple yet fascinating scientific concepts.
Starting with the most basic refrigerator model, this article will go through how modern refrigerators work as well as the secrets behind their excellent energy efficiency.
Refrigerators work on the simple idea of continuously passing a colder liquid around the thing to be cooled. Let’s look at how this continuous cold liquid flow is done within a refrigerator.
The most important component of refrigerators is a simple mechanism called a throttling device, which uses a capillary tube to produce a cold liquid via the throttling phenomenon. For successful throttling at the inlet, the refrigerant must be in a liquid condition under high pressure.
When the liquid runs through the throttling mechanism, it causes a huge pressure reduction. As the pressure reduces, the boiling point of the liquid drops, and the refrigerant liquid evaporates. The energy required for such evaporation comes from the refrigerant, thus its temperature drops.
Please note that just a fraction of the refrigerant is evaporated here; this is an important quality of the refrigeration fluid; it should be able to change phase while varying pressure under normal temperatures.
The next step is to simply pass this cold liquid over the body that needs to be cooled. During the heat absorption process, the refrigerant evaporates and transforms into pure vapour. Because there is no phase change during this process, the refrigerant temperature remains constant. This heat exchanger is known as the evaporator.
We have achieved the desired cooling effect with the help of creative airflow circulation inside the refrigerator using an evaporator fan. If we can take this low-pressure refrigerant to the state before throttling that is high-pressure liquid, we will be able to repeat this procedure.
The first step is to raise the pressure, which is accomplished by using a compressor. The compressor will return the pressure to its initial value, which is accomplished by using a reciprocating type compressor. However, because it is compressing gas along with pressure, the temperature will rise, which is unavoidable.
We’ll need to add another heat exchanger to convert the refrigerant to a liquid condition now that it’s a high-pressure vapour. This heat exchanger is located outside the refrigerator and will dissipate heat into the environment. The vapour will transform into liquid and the temperature will return to normal. A heat exchanger known as a condenser is a type of heat exchanger.
Now that the refrigerant has returned to its original state, it may be fed back into the throttling mechanism. By repeating this cycle over and over, we can generate a continual cooling effect. This cycle is known as the vapour compression cycle. The performance of a refrigerator can be measured using a term known as the coefficient of performance. Because the output is divided by input, the performance coefficient can be easily defined as follows:
This is the most basic refrigerator ever made. It will operate OK in principle, but it will have a lot of problems in practice. Let’s have a look at these problems and how to solve them.
One major issue is the frost that forms in the freezer compartment. Because the circulated air contains moisture, when it comes into contact with the cold evaporator coil, it condenses and forms a frost around the coil. This ice coating prevents further heat transfer, and the refrigerator becomes inefficient over time.
Back of Refrigerator
This is why a pan and water condensate can be seen at the bottom of your refrigerator. Furthermore, modern refrigerators do not have condenser fins at the back of the refrigerator; instead, they use a compact condenser arrangement, which is assisted by a cooling fan and achieves the same heat rejection purpose.
The hot air ejected by the fan can be used to effectively evaporate the water condensate created during icing. The modified refrigerator now looks like this, with an unusual temperature distribution in various regions of the fridge. The temperature decline throughout the capillary tube is also illustrated in this diagram.
Outside the refrigerators, there are two refrigerant lines: one that transports cold liquid from the capillary tube to the evaporator coil, and the other that transports vapour from the evaporator. However, if you examine your home refrigerator, you will only see one line.
What is causing this?
The capillary tube, which does not have to be a spring-like device and can be a long straight tube as seen below, is the most important portion of the refrigerator. You will only see one line on your home refrigerator since this straight capillary tube goes inside the evaporator exit coil.
This basic strategy has a lot of benefits. We know that the refrigerant temperature does not rise during the heat absorption process at the evaporator; instead, its phase changes. This means that allowing the capillary tube to come into touch with the evaporator exit line will significantly reduce the refrigerant temperature in the capillary tube.
This will result in bigger temperature reductions in the capillary tube, resulting in a better refrigeration effect. On the other hand, because the evaporator exit coil absorbs heat, the refrigerant in the evaporator exit line will be turned into pure vapour. This is beneficial for compressors that are only intended to handle pure vapour. A filter dryer is used to remove any moisture from the refrigerant that could become trapped during compressor operation.
Let us now look at the most current refrigerator innovation that has completely revolutionised modern refrigerators. compressors with digital inverters A compressor is the heart of any refrigerator and the device that gives life to the entire system. You may have noticed that the compressors in older refrigerators are either on or off. This is a single-speed technology that turns the compressor off when the inside temperature of the refrigerator reaches an optimum level.
The compressors will be turned on, and you will notice that the temperature control inside the refrigerator is not smooth. Furthermore, such abrupt speed variations of the compressors will result in compressor component durability issues. With the help of a digital inverter compressor, a variable compressor speed is possible, allowing for smooth and efficient evaporator temperature control.
The ac power is converted to dc using a controller, which provides variable frequency electric power to precisely control the motor speed. A BLDC digital inverter compressor, the most common motor utilized in this technique, uses at least 40% less energy than single-speed compressors.
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