It might seem like your refrigerator works by "making things cold," but physically, it does the opposite. A refrigerator is a heat mover. Its job is to extract thermal energy from the cool interior and push it out into the warmer kitchen.
Because heat naturally wants to flow from hot to cold, moving it in the reverse direction requires work—and that work requires electricity
Text description of the Refrigeration Cycle image.
The image illustrates a diagram of the refrigeration cycle, divided into two sections representing low and high pressure. On the left, the blue section is labeled "Low Pressure" and depicts cool liquid flowing through a coiled tube, marked as the evaporator. Snowflake symbols and the text "COOL AIR" are included to signify cooling. On the right, the orange section is labeled "High Pressure" and shows hot liquid moving through a similar coiled tube, designated as the condenser, accompanied by red circles and the text "HOT AIR" to indicate heating. At the center of the diagram, a compressor connects the two sections, with arrows indicating the flow direction. An expansion valve is positioned between the evaporator and condenser, illustrating the complete cycle.
The principle of operation of a refrigerator is similar to an air conditioner. It moves the heat energy from inside to outside. There are four basic components in a refrigerator and their functions are as follows:
- The expansion valve acts like a nozzle. High-pressure liquid refrigerant squeezes through it and suddenly expands into a low-pressure zone. Key physics: When a fluid expands rapidly, its temperature drops. This is the same reason aerosol cans feel cold when sprayed. Now the refrigerant is cold and ready to absorb heat.
- Evaporator - These are the coils you might see inside the freezer or behind the back panel. The cold, low-pressure refrigerant flows through them and evaporates (turns from liquid to gas). Why this matters: Evaporation requires energy. The refrigerant steals that energy as heat from the air and food inside the fridge. Result: Your food cools down, and the refrigerant warms up as it carries that heat away.
- Compressor - This is the refrigerator's 'engine'—and the part that uses the most electricity. The compressor squeezes the now-warm refrigerant gas, increasing its pressure and temperature dramatically (think of pumping up a bike tire: the pump gets hot). This compression step requires significant electrical work. The refrigerant leaves the compressor hotter than the kitchen air, so it can now release its heat outward.
- Condenser - These are the black coils you might feel on the back or bottom of your fridge. The hot, high-pressure refrigerant flows through them. Because the refrigerant is now hotter than the kitchen air, heat naturally flows out of the coils and into the room. The refrigerant condenses back into a liquid, ready to repeat the cycle. Why you feel warmth: That heat you sometimes feel near your fridge? That's the heat originally taken from your food, plus the energy used by the compressor."
How Does a Refrigerator Work?
How does a Refrigerator Work? (3D Animation) (4:10)
Transcript: How does a Refrigerator Work? (3D Animation) (4:10)
Have you wondered how the refrigerator in your home works. Refrigerators which have become an integral part of every household works on some simple and scientific principles starting from a simple and basic model this video will elaborate on the workings of a modern refrigerator and its High Energy Efficiency.
Simply a cold liquid is continuously passed inside the refrigerator around the object to be cooled. Now let's see how this continuously moving cold liquid is achieved inside the refriger Ator. The most crucial component of the refrigerator is a device named throttling device. Here a capillary tube with a small diameter is taken as the throttling device and cold water is produced from the throttling phenomenon.
For Effective throttling the refrigerant should be in a liquid state at high pressure. The throttling device is a huge obstruction to the flow so a huge pressure drop occurs when liquid passes through the throttling device. Due to the drop in pressure the boiling point of the liquid drops and turns it into vapor. The energy required for the refrigerant liquid to evaporate comes from the refrigerant so its temperature drops.
Now we have converted the room temperature liquid at high pressure to cold and low pressurized Vapor but the thing to be noted is that only a small portion of the liquid is evaporated. Then the liquid is passed through the object to be cooled. During the heat absorption process the refrigerant further evaporates and all the remaining refrigerant turns into pure Vapor.
Since there is a change of phasee In the period the temperature of the liquid does not change. This heat exchange system is called evaporator. By the clever use of evaporator fans inside the refrigerator one can maintain different temperature levels inside the refrigerator so we have achieved the refrigeration effect inside of our refrigerator.
Now if we can convert the cold low press vapor into the state before that is high press liquid we will be able to repeat the same process again. Now at first we have to convert the low press vapor into High Press vapor and for that we use a compressor as you can see that a reciprocating type compressor is used here however the compressor is also compressing gas with pressure so the temperature inevitably Rises.
Now we've converted the refrigerant into High Press Vapor. To convert the vapor into a liquid state we introduce another heat exchanger which is fitted outside of the refrigerator thus it will liberate heat to the surroundings and its temperature will reach its normal level. This heat exchanger is known as a condenser.
Now the refrigerant is back in its normal state so it can be fed into the throttling device again. Just by repeating this process again and again we will be able to achieve a continuous cooling effect. This is the most basic refrigerator ever.
This refrigerator will work perfectly in theory but in practice we will experience different sorts of issues let's see what these issues are and how to overcome them. One major issue is the frost developed in the freezer compartment. The air in the compartment has moisture content which will turn into Frost when it comes in contact with the evaporator coil.
Such ice coating prevents further heat exchange and the refrigerator becomes inefficient over time. To overcome this issue heating rods are used to remove the frost produced and the condensate is collected in the refrigerator somewhere near the compressor.
Moreover in modern refrigerators you won't be able to see the condenser fins on the back of the refrigerator instead they use a compact condenser system that uses a cooling fan and the same heat rejection system is achieved here. Cold air cools the hot High Press vapor and returned to the throttling device.
In modern refrigerators you may not see the throttling device as presented here because the throttling device can also have a long wire shape instead of a curly spring shape. A filter dryer is used to remove any moisture content present in the refrigerant that might become trapped in the compressor operation.
We hope this video gave you a clear insight into the workings of a modern refrigerator thanks for watching the video.
Did you know that different refrigerator styles have different energy efficiencies? For decades, the only common design was the top-freezer model. But is that design the most efficient?
Contrary to popular belief, the answer is no. The most efficient configuration is typically a refrigerator with the freezer on the bottom. This is because of how air moves: warm air rises and cold air sinks. A bottom-freezer design takes advantage of this natural behavior to conserve energy.
Below is an image of the most common types of refrigerators available, along with their relative efficiencies.
Text description of the Refrigerator Types image.
Diagram of four refrigerator types shown in order from the least energy use to the most energy use, bottom freezer, four door, top freezer, and side by side.