If you’re like most people, you don’t worry that much about your refrigerator’s inner working mechanism. You become aware only when it breaks down, or it’s time to fix it. It’s always helpful to know how does a refrigerator work.
To get the most out of this indispensable appliance — we at Tech Insider 360° are here to guide you.
This article intends to help you learn about how does a refrigerator work. How it helps keep your foodstuffs cold.
The refrigeration process helps freeze water, produce ice cream and delicious frozen yogurt. It helps preserve your fruits, vegetables, and other types of food.
The edible products get rotten easily at an atmospheric temperature as under these conditions; bacteria can easily survive. Bacteria cease to exist at temperatures below 4 degrees Celsius, and therefore the products remain healthy and fresh.
What are the main components?
The refrigerant is a fluid. The main component used in the refrigeration cycle. It goes through a change of states back and forth from a liquid to gas.
The most commonly known fluid we know is CFCs. Yes, the gas responsible for ozone depletion.
Other fluids used as refrigerants are ammonia, propane, and sulfur dioxide.
The refrigerant fluids are under high pressure inside the compressor. It then travels through the coil visible at the back of the refrigerator.
Compressors act as a pump that ensures that the refrigerant flows through the system. Compressors come in different types, namely, centrifugal, reciprocating, and rotary. These types are common compressors in most refrigerators.
In a refrigeration system’s cooling process, the vapor refrigerant absorbs the heat, followed by the compressor pressurizing the refrigerant.
When it goes to the condenser, the refrigerant loses heat and turns into liquid. Condensers are of mainly three types, namely :
Air-cooled condensers make use of air to remove heat from the refrigerant. It works in two ways, natural convection and forced convection.
In natural convection, the air outside the condenser coils absorbs heat from the refrigerant inside the coil. When this air gets hotter, it rises above, and cold air replaces it, thus absorbing the heat.
This cycle keeps repeating until the refrigerant is condensed.
Instead of relying on air to do it naturally, fans or blower is used in forced convection. The fans or fins draw in air and blows them over the coils to remove heat from the refrigerant.
Water is used as the fluid to remove heat from the refrigerant. Even water-cooled condensers are of three types: 1) Double tube condenser. 2) Shell and coil condenser. 3) Shell and tube condenser.
In double tube condensers, a tube filled with water absorbs most of the heat, but natural convection also plays a part since air is in contact with the tube.
The shell and coil condenser is the most easier to build and low cost. A coil of a finned tube of water is welded to the shell, the refrigerant flowing to this condenser is cooled by the circulating water.
The shell and tube condenser works by pumping water through the tube, which removes the heat from the refrigerant in the shell. Installing fins in pipes can remove more heat. This condenser doesn’t require much maintenance and lower in cost.
In evaporative condensers, both air and water is the fluid to remove heat from the refrigerant. Water is sprayed over the coil while air is also blown simultaneously into the condenser.
Heat is taken away as the sprayed water is evaporated from the surface of the coils. All this water is circulated through the sump of the pump. The evaporated water is replaced by more addition of water supplied to the sump.
The function of the evaporator is the opposite of what the condenser is. The refrigerant, which is in the liquid state, is evaporated to gas while losing its heat in the process.
The compartment inside the refrigerator is cooled down this way to the desired degree. The evaporator performs the actual cooling process.
The pressure from the liquid refrigerant is removed before it enters the evaporator. This happens in the expansion valve. This allows the refrigerant to change its state from liquid to gas.
Usually, thermostats are located inside the fridge and have a knob that allows users to change their temperature.
If a consumer sets the desired temperature, the climate is controlled by the thermostat by regulating the electricity flow to the compressor.
The thermostat ceases electricity to flow to the compressor when the refrigerator’s interior is desired. This allows electricity to flow only when the heat increases in the compartment, triggering the compressor.
The Defrost System
The defrost system helps to remove the excess ice from the evaporator floor. The thermostat button may manually control the defrost mechanism or an automated system consisting of the electric heater and the timer.
These were some of the domestic refrigerator’s internal components; now, let us see the outer parts.
The freezer compartment stores the foodstuffs at freezing temperatures. The temperature here is below zero degrees centigrade. Water, including many other fluids, usually freezes at this temperature.
The thermostat control consists of a round knob with a temperature scale that allows us to set the appropriate temperature.
It is essential for keeping the correct refrigeration cycle. Proper thermostat setting, as per the requirements, will help save loads of energy bills for refrigerators.
The largest part of the refrigerator is the compartment. Here, all food products are at a temperature above zero degrees celsius but in a cold state.
The fridge compartment divides into various smaller shelves, such as a meat keeper and others as needed.
The heating and cooling cycle
When gas compresses into a liquid, it releases heat. When liquids expand to become gases, it absorbs heat. This physical mechanism ejects heat from the inside of the refrigerator to the outside.
Evaporation occurs at low temperatures and low pressure, and high temperature and high-pressure condensation occur.
Thus, heat moves from a lower temperature area ( i.e., within the refrigerator cabinet) to a high-temperature location ( i.e., kitchen room). That’s how a refrigerator works. The refrigeration cycle repeats this way.
Why does it take longer to cool inside the fridge?
The foodstuffs contain plenty of water, made of very lightweight molecules. Even a small quantity of water-based liquid (or solid) contains many molecules, each taking energy to heat or cool off.
This is why boiling even a cup or two of water takes a few minutes: there are many more molecules to heat than if you’re trying to heat anything like a cup of molten iron or lead pipe.
The same applies to cool: removing heat from watery liquids such as fruit juice or solid requires energy and time. That is why it takes time to freeze or cool down. This is to help you understand how does a refrigerator work.
Tips for maintaining your refrigerator
- While you may not see the coils, keeping them free from dust, debris, and pet hair allows the refrigerator to run better and more effectively. The coils are typically located at the bottom or in the back of the unit.
- Frequently check the temperature in both your unit’s refrigerator and freezer parts. This is important for the protection of foodstuffs as well as for making the fridge work effectively.
- The refrigerator’s compartment should be about 37 to 40 degrees Fahrenheit, and the portion of the freezer should be set at zero degrees Fahrenheit.
- If your gasket doesn’t seal well, cold air inside will escape, making the device work harder and taking more energy to hold the temperature right. For signs of wear and tear, check the gasket regularly.
- Many people may not know; that refrigerator ice makers and water dispensers typically have changing filters. For detailed suggestions and replacement information for your model, review your manufacturer’s instructions.
- When the door is open, the fridge needs to work harder to maintain the right temperatures.
- The refrigerators become hard to stabilize if you put hot, steaming foodstuffs inside. Thus avoid doing this.
- Although food safety is crucial, before putting them in your refrigerator, take a few minutes to cool down hot products.
- To remove condensation, most refrigerators rely on a drain hole and a drip tray. Remove any food debris and mineral deposits from the drain hole as guided in the owner’s manual. Then scrub the pan for the drain.
- If the temperature goes over the setpoint sensors inside the refrigerator, the compressor activates itself, and the cooling cycle begins.
- The unit draws, pressures, condenses it in the cold liquid refrigerant, and increases temperature, converting it into a gas.
- On the outside of the refrigerator, the compressor moves the hot gas into the condenser coils, where it comes into contact with the lower air temperature in the room and returns to a liquid state.
- The cooled liquid continues on its path to the evaporator, passing through the refrigerator compartment’s inside coils and the freezer.
- The coolant absorbs the hot air from inside the refrigerator, reducing the temperature to the desired set point.
- The refrigerant evaporates, converts back into a gas, and returns to the compressor to continue the cycle.
- Refrigerators spend around 10% of electric energy in average households.
- A refrigerator is more effective when it has more items in it.
- 15th November is the Annual “Clean Your Refrigerator” Day in the United States.
- Back in 1911, General Motors produced the first commercial household refrigerator. Their first successful line was Kelvinator which was holding close to 80 percent of the market by 1923.
- By 1956, 80 percent of U.S. households had a fridge. That number rose to 99.5 percent by 2005. About 15 percent of American families have two fridges.