Just like about most of our household appliances, we don’t think about how a fridge actually works. Thoughtlessly, you put your products in the fridge, close the door and can rely on them -until their expiry date- to stay in the desired condition. But what system is behind it? Contrary to what most people think, a fridge performs its function not by cooling, but by dissipating heat. How this works? We explain it to you below.
The compressor as the core of the fridge
What a fridge actually does is remove heat from food and dissipate it into the environment. So it extracts heat from your products. For this reason, the back of your fridge is also always hot and the advice is to keep enough space between the fridge and the wall so that the appliance can dissipate its heat. A fridge needs a compressor, condenser, evaporator, refrigerant gas and a valve to perform its cooling function.
At its core is the compressor, also known as a heat pump. This motor circulates the refrigerant through the tubes you often see on the rear exterior of your fridge. However, many of the tubes are also inside the appliance itself. The function of the compressor is to compress gas into liquid.
How is temperature decline triggered? A comparison
A fridge extracts heat from the food you put in it. The appliance cleverly uses that heat to evaporate the liquid refrigerant. This causes the temperature to drop. Compare this to water on your skin. If you don’t dry yourself immediately after a shower, the water extracts heat from your skin to evaporate. This results in a cold feeling, even when the temperature in your bathroom is more than pleasant.
Refrigerant: liquid and gaseous
The first step of the refrigeration process involves compressing the refrigerant gas and letting it condense into a liquid. The compressor circulates this and pressurises it. The refrigerant gas heats up considerably as a result of this process. After all, pressure increase leads to temperature rise. The resulting heat must be dissipated into the environment to cool the refrigerant to room temperature. The coolant comes into contact with the ambient temperature on the outside of the refrigerator.
If this cools it sufficiently, it then cools the inside of the fridge. The liquid enters a larger-diameter tube via a finer tube. This leads to pressure drop and thus temperature drop. The coolant thus returns to the compressor. And once it does, it can be reused again for this same process.
A suitable ambient temperature as a prerequisite for the cooling process
The cooling process described above applies to all electric refrigerators, including the increasingly popular American fridge in our country today. Are you looking for a new fridge? Then it is important that you can provide the appliance with the right environment to do its job properly. The climate class of each fridge indicates the ambient temperatures in which it can operate. Here, the classes N, SN, ST, T and SN-ST are used. Each category has minimum and maximum temperature values associated with it.
Is the ambient temperature below the minimum value? Then the refrigerator cannot evaporate its refrigerant properly. Is the ambient temperature above the maximum value? Then the refrigerator cannot properly dissipate its heat. Both situations lead to reduced functioning of the appliance and higher energy consumption.