We all know what our refrigerator does, but how does it do it? That low hum your fridge makes is clever science — turning gas to liquid and back again to keep your food fresh and cool. To keep food fresh, your refrigerator must stay at a low temperature so harmful bacteria can’t grow. Let’s delve into the refrigeration cycle and explain how it all works.
What is the basic concept of refrigeration?
A refrigerator uses pressure, condensation and evaporation in a closed circuit to remove heat from inside the fridge. The fluid that travels around this circuit is called the refrigerant. The main components are:
- Compressor — controls the flow of refrigerant
- Condenser coils — on the outside of the fridge
- Expansion device
- Evaporator coils — inside the fridge
The refrigeration cycle, step by step
- The compressor squeezes the refrigerant vapour, increasing its pressure and temperature to create a hot gas. This gas is pushed into the condenser coils on the outside of the refrigerator.
- In the coils on the back of the fridge, the hot gas meets the cooler air of the kitchen and condenses into a high-pressure liquid.
- The liquid refrigerant passes through the expansion device, where its pressure is quickly reduced. It expands and some rapidly turns to vapour, cooling down as it flows into the evaporator coils inside the fridge.
- The cold liquid refrigerant absorbs the warmth inside the fridge, cooling the air and food.
- Finally, the refrigerant evaporates into a low-temperature, low-pressure gas and flows back to the compressor, where the cycle begins again.
What temperature is optimal for my refrigerator?
The refrigerator temperatures for keeping food safe are:
- Fresh food — between 0°C and 4°C
- Chiller compartment — close to 0°C
The Australian Standard for fridges states the fresh food compartment should average 3°C — below 4°C, but not so cold you freeze your food. For more, see our guide on what temperature your fridge and freezer need to be. Try to close the fridge door promptly each time, and avoid overloading it, as this reduces airflow and makes the fridge work harder. A reasonably priced fridge thermometer lets you check the temperature stays below 5°C to keep your food safe.
For more information on using your refrigerator, call Sea Air Mechanical Services, your local refrigeration specialists, on 0401 787 183. We specialise in refrigeration repairs, servicing and maintenance on the Sunshine Coast and across North Brisbane.
