How a fridge works

Refrigerators work using a special form of gas cycle that compresses, heats and cools gas to keep the fridge at a specific temperature.

Refrigerators used to contain ammonia gas for the cooling cycle, but as ammonia was found to be poisonous to humans the gas was replaced with CFC’s (chlorofluorocarbons). CFCs are considered a safer gas to ammonia and were used up until the 1970s, when it was confirmed that CFCs were harmful to the ozone layer.

From the 1990s onwards refrigerators used refrigerants, which are far less damaging to the environment.

The cycle

The fridge contains a compressor that compresses the gas. The gas is then pressurized and heated. The hot gas passes through a set of coils, located on the back of the fridge, which dispel the heat from the gas.

The gas is then concentrated into a liquid through high pressure. Once the liquid has formed, it runs through the expansion valve, which sucks the remaining gas out, while vaporizing the liquid – a process that results in a dramatic reduction in temperature.

The temperature of the vapour and liquid falls to –27°F, and consequently keeps the inside of the fridge cold. The cold gas is then sucked up through the compressor where the cycle is repeated.

 A fridge's purpose

The sole purpose of having a fridge is to keep food cold and fresh, which allows the food to last longer. Keeping the temperature low slows the growth of bacteria and therefore stops food from spoiling immediately. Meat or milk can spoil in hours if proper refrigeration isn’t applied. Freezing can stop the development of bacteria altogether, allowing foods and drinks to last for a number of months. 

There are no comments yet - add yours below

This helps to discourage spam