Most of us take our refrigerators for granted. We assume when we need a cold drink or a scoop of ice cream, we just need to open our fridge or freezer and help ourselves. When it comes to commercial fridges, however, you probably take things a little more seriously. You depend on them to keep food at safe temperatures to protect your customers from getting sick.
But have you ever wondered how your fridge and freezer actually work? They depend on something called refrigerant to manage the cooling process. Here we explain how the refrigerant in your refrigerator and freezer works.
What is Refrigerant?
Often mistakenly referred to as Freon, refrigerant is an agent used to cool appliances including refrigerators, mobile refrigerators, air conditioners, heat pumps and more. Freon is actually a brand name, so does not necessarily apply to all refrigerants, much like “Kleenex” is used for tissue paper! When a fridge isn’t keeping food cold, chances are it could be time for a refrigerant top off.
Refrigerant absorbs heat and leaves cool air behind using a thermodynamic process which continuously turns the agent from a liquid into a gas and back again. Many refrigerants containing HydroFluoroCarbons tend to be less eco-friendly, while those containing HydroCarbons are considered better for the environment.
Why is Food Refrigeration Important?
Low temperatures reduce the risk for harmful bacteria to reproduce. It slows down the reproduction rate helping keep food safer for longer. The refrigerator keeps food cold by constantly transferring heat from inside the compartment out. The main thing that keeps everything cold is the refrigerant.
Circulation and Evaporation
Refrigerators circulate the refrigerant to keep things cool. Since warm air is constantly introduced when the door is open, refrigerant is required to absorb and remove it. The circulation is needed to change the refrigerant from a liquid into gas to assist with heat management through a process called evaporation. When something evaporates it causes cooling. For example, this is why we sweat.
When we get overheated, we sweat, which evaporates helping to cool our bodies. For fridges and freezers, to start the process, pressure on the refrigerant is reduced. This is handled by an outlet called a capillary tube. If this is hard to picture, think of what happens when you use an aerosol product like an air freshener. When you push the head of the spray it releases its contents into the lower pressure open space which turns it from a liquid into the gas that forces the contents out.
Since the cooling is dependent on this transformation from liquid to gas, your fridge has to keep converting liquid to gas and then gas back to liquid. This requires compression so that the gas is compressed to a higher temperature and pressure. The compressor of the fridge works much like a bike pump, creating heat when it is pumped and compresses the air.
When the compressor works properly, the gas is under high pressure and becomes hot again. So now that it’s hot, the condenser needs to cool it, so it changes back into liquid. The refrigerant can circulate back to the evaporator in liquid form, so the process starts again.
To understand the process completely it’s helpful to understand the components involved:
The compressor circulates the refrigerant throughout the system, using pressure to help warm the refrigerant.
The condenser cools the refrigerant inside in gas form and then “condenses” it, so it turns back into liquid.
The evaporator keeps everything cold. So when the refrigerant converts into gas in the evaporation process, the evaporator cools the storage area of the fridge to keep food and drinks cold.
This thin piece of tubing assists with expansion as the liquid refrigerant goes through the tube. It sprays the refrigerant into the evaporator’s low-pressure environment just like an aerosol can.
You probably already know the thermostat controls the cooling process. Its job is to monitor temperatures and turn the compressor on and off to maintain consistent levels. It uses sensors to tell when the fridge is cold enough so it can turn the compressor off and vice versa.
Regardless of the type of fridge or freezer you own, the process is pretty much the same. Refrigerant works hard to keep food fresh, and your customers free of foodborne illnesses.
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