Do you have any articles about refrigerator?

Question

I want to know how does a refrigerator work.

Answer 1

All residential refrigerators operate in a similar fashion. All refrigerators have these components: a compressor, condenser, evaporator, capillary tube, and a thermostat. Refrigerators with an automatic defrost cycle have small heaters in strategic places to defrost ice buildup. The basic principle of refrigeration is that you remove heat. Some people think refrigeration works by cooling something, but it's just taking heat away. The refrigeration process is really simple. Your refrigerator takes warm air and makes it cooler by transferring the heat using evaporation principles.



Refrigeration starts with the compressor. The compressor is the workhorse for the refrigerator. The compressor is turned on when electricity is sent to it by the thermostat. It mechanically compresses, or squeezes, a refrigerant gas. This compression causes the gas to become a hot, high-pressure gas. Next, this hot gas flows through a set of condenser coils where it dissipates its heat, and condenses into a liquid.



The condenser coil is a system of bent tubes that run through thin pieces of metal. These thin pieces of metal are sometimes referred to as fins. These fins resemble a radiator that you would see in a car. The high-pressure gas from the compressor flows into the condenser coils and changes state to become a liquid. As this change takes place, the tubes radiate heat from the refrigerant gas. This heat is conducted away from the coils by the fins attached to the tubes. The capillary tube connects the condenser coils to the evaporator coils, and it controls the pressure of the refrigerant as it enters the coils.



As the refrigerant passes through the exit of the capillary tube, the liquid refrigerant expands, boils, and evaporates into the evaporator coils, and it becomes a cold, low-pressure gas. This cold gas flows through the evaporator coils, which allows the gas to absorb heat, and by absorbing that heat; it cools down the air flowing past the coils. The fan inside the freezer’s compartment circulates the air to keep the temperature uniform and constant. Because the evaporator coils are so cold, they cause any humidity in the air to freeze onto the evaporator coils as ice or frost. The refrigerant is then sucked back into the compressor where the process is repeated. A thermostat controls the process, helping to keep frozen foods at the desired temperature to maintain freshness.



The fan that is located inside the refrigerator's freezer compartment circulates the air to keep the temperature uniform and constant. The process is regulated through the use of thermostats and switches, which help to keep your foods at a desirable temperature to maintain freshness without freezing the food, or leaving it so warm that it spoils. When the temperature is cool enough, the thermostat senses it, and tells the compressor and fan to take a break. When it gets too warm again, the same thermostat tells the compressor and fan break time is over.



Most modern refrigerators have an automatic defrost system which includes three major components: the defrost timer, defrost thermostat, and defrost heater.



The defrost timer, approximately every 6 to 12 hours, cuts off the power to the compressor and cooling system, and switches on the defrost heater. As the ice melts, it drips through a drain hole, through a tube, and into an evaporation pan where it evaporates with the help of a fan that blows warm compressor air over it to improve evaporation. The defrost heater has an electric heating element and is located just beneath the evaporator coils. This heater element gets hot, and due to its proximity to the coils, any ice or frost build-up usually melts pretty fast. When the defrost timer advances, or the defrost thermostat, located near the evaporator coils, detects that the temperature by the coils has raised up to a certain pre-set temperature, the cooling unit kicks back in.

Answer 2

PRINCIPLE:



The basic idea behind a refrigerator is very simple: It uses the evaporation of a liquid to absorb heat.



THE PURPOSE OF REFRIGERATION:



The fundamental reason for having a refrigerator is to keep food cold. Cold temperatures help food stay fresh longer. The basic idea behind refrigeration is to slow down the activity of bacteria (which all food contains) so that it takes longer for the bacteria to spoil the food.



­As we learned in the introduction, the basic idea behind a refrigerator is to use the evaporation of a liquid to absorb heat. You probably know that when you put water on your skin it makes you feel cool. As the water evaporates, it absorbs heat, creating that cool feeling. Rubbing alcohol feels even cooler because it evaporates at a lower temperature. The liquid, or refrigerant, used in a refrigerator evaporates at an extremely low temperature, so it can create freezing temperatures inside the refrigerator. If you place your refrigerator's refrigerant on your skin (definitely NOT a good idea), it will freeze your skin as it evaporates.



There are five basic parts to any refrigerator (or air-conditioning system):



COMPRESSOR

Heat-exchanging pipes - serpentine or coiled set of pipes outside the unit



EXPANSION VALVE

Heat-exchanging pipes - serpentine or coiled set of pipes inside the unit



REFRIGERENT - liquid that evaporates inside the refrigerator to create the cold temperatures



Many industrial installations use pure ammonia as the refrigerant. Pure ammonia evaporates at -27 degrees Fahrenheit (-32 degrees Celsius).



The basic mechanism of a refrigerator works like this:



The compressor compresses the refrigerant gas. This raises the refrigerant's pressure and temperature (orange), so the heat-exchanging coils outside the refrigerator allow the refrigerant to dissipate the heat of pressurization.



As it cools, the refrigerant condenses into liquid form (purple) and flows through the expansion valve.



When it flows through the expansion valve, the liquid refrigerant is allowed to move from a high-pressure zone to a low-pressure zone, so it expands and evaporates (light blue). In evaporating, it absorbs heat, making it cold.



The coils inside the refrigerator allow the refrigerant to absorb heat, making the inside of the refrigerator cold. The cycle then repeats.





THE REFRIGERATION CYCLE:

The refrigerator in your kitchen uses a cycle that is similar to the one described in the previous section. But in your refrigerator, the cycle is continuous. In the following example, we will assume that the refrigerant being used is pure ammonia, which boils at -27 degrees F. This is what happens to keep the refrigerator cool:



The compressor compresses the ammonia gas. The compressed gas heats up as it is pressurized (orange).

The coils on the back of the refrigerator let the hot ammonia gas dissipate its heat. The ammonia gas condenses into ammonia liquid (dark blue) at high pressure.

The high-pressure ammonia liquid flows through the expansion valve.

You can think of the expansion valve as a small hole. On one side of the hole is high-pressure ammonia liquid. On the other side of the hole is a low-pressure area (because the compressor is sucking gas out of that side).





The liquid ammonia immediately boils and vaporizes (light blue), its temperature dropping to -27 F. This makes the inside of the refrigerator cold.



The cold ammonia gas is sucked up by the compressor, and the cycle repeats.

Answer 3

short and simple:

Refrigerators have a liquid running through it (usually Refrigerant-22 or 134a). Going through several components it accomplishes cooling the inside of the refrigerator. The liquid goes "inside" a refrigerator and sucks in the heat since its colder. ( heat always flows from hot to cold... so heat flows into the liquid making the inside of the fridge colder). then the liquid goes through a compressor so it becomes hotter than the surroundings therefore giving off heat that it picked up inside. It is then expanded making it again very cold to go in the fridge again. and thus the cycle goes.