How do refrigerators function to keep your food cold? Discover the science behind it.

The refrigerator stands as one of the most groundbreaking inventions for our kitchens. Prior to the refrigerators we know today, people depended on natural cooling methods like streams, caves, iceboxes, and communal cooling houses. This limited the amount of perishable food they could store. Fred W. Wolf invented the first home electric refrigerator in 1913, building on numerous scientific advances from earlier discoveries, changing how we store and preserve food.

Ever wondered how these essential appliances work? Keep reading to find out more.

How does a refrigerator keep things cool?

The refrigeration process relies on five core components: refrigerant, which shifts between gas and liquid forms; a compressor; the condenser coils (on the outside of the fridge); the evaporator coils (inside the fridge); and an expansion device situated between the condenser and evaporator coils. Here's how they work together to chill your food.

1. The refrigerant gas is heated and pressurized.

The compressor, typically found at the bottom or rear of the fridge, takes in refrigerant gas, compresses it to raise both its heat and pressure, and then moves it into the condenser coils.

2. The condenser coils transform the refrigerant into a liquid.

As the hot gas moves through the condenser coils, it cools and turns into a liquid. The heat from the gas is expelled into the surrounding air, which is why the back of your fridge might feel warm.

3. The expansion device reduces the pressure.

The refrigerant liquid enters the expansion device, a valve that drastically lowers its pressure. This pressure reduction causes the liquid to expand into a mixture of liquid and vapor, which also results in cooling.

4. The refrigerant extracts heat from inside the fridge.

The cold, low-pressure refrigerant flows into the evaporator coils, where it absorbs the warm air inside the fridge, thereby cooling the area around your food. During this process, the refrigerant boils and evaporates, changing into a gas.

5. The refrigerant gas flows back into the compressor.

And the cycle starts again!

How Does a Freezer Work?

Freezers operate using the same technology as refrigerators but maintain much colder temperatures. While freezers are typically set at or below 0°F, refrigerators usually operate at 40°F.

Both fridges and freezers perform best when they're adequately stocked. The cold or frozen items help maintain the overall low temperature and keep the rest of the contents cool. However, be careful not to overfill—leaving space for airflow is crucial for efficient operation.

How Does a Fridge Water Dispenser Work?

Your refrigerator is connected to your home's cold-water supply. When you press the button or paddle of the water dispenser, a sequence of switches is triggered, opening valves to allow water to flow through tubes in the fridge and out the dispenser. Some models feature a filter that removes impurities from the water as it passes through, and a reservoir, often located behind the crisper drawers, that helps keep the water cool.

Frequently Asked Questions

• Why is my fridge not cooling properly?

  There are often simple solutions, such as rearranging the items inside the fridge to avoid blocking the air vents, adjusting the thermostat to the correct temperature, or cleaning the door seals to ensure they close tightly. Dirty condenser coils (located outside the fridge) are also a frequent issue. When clogged with dust or grease, they can't cool the refrigerant efficiently. Refer to your manual for proper cleaning instructions; typically, they should be cleaned every two to three months. Other potential causes could be a malfunctioning condenser fan, evaporator fan, or compressor, or you may need to move the fridge to a location with better airflow. If you can't figure out the problem or fix it, it's time to call a professional!

• What happens to the fridge when the power goes out?

  When the power goes out, the refrigeration cycle stops because it relies on electricity. Food starts to spoil if the fridge temperature rises above 40°F, but fortunately, food should stay safe for up to four hours without power, according to the USDA, as long as you avoid opening the doors, which will let cold air escape and warm air enter.