- February 28, 2018
- Posted by: Joel Payne
- Category: refrigeration
To those of us who have forgotten the vast majority of our high school physics lessons, it seems to make implicit sense to think of refrigerators ultimately as things that create cold.
According to the laws of thermodynamics, it’s actually impossible to generate cold. This is because “cold” isn’t in a property that is distinct, it is simply the absence of heat. In the same way that darkness is merely an absence of light and not something that we can create with any technology, that doesn’t merely block a source of light from entering a space.
So how does a refrigerator keep its contents cool? Here’s what’s currently going on inside your refrigerator. I’ll explain by using this handy graph from “explain that stuff” (explainthatstuff.com).
The pink line is the insulated divide between the outside of your refrigerator and the internal compartment that keeps your food fresh and cool.
At position 1 the refrigerators coolant is moving through the pipes at a warm temperature as it hits the expansion valve at position 1, here the pressure it’s stored under is released causing the liquid to become a gas and rapidly loses it’s heat energy as it expands. This operates the same way as when you spray a deodorant can the gas feels cooler than room temperature despite having been stored in a room temperature can.
At position 2 the coolant gas flows through the pipes in contact with the chilled cabinet of your fridge taking on the excess heat within the fridge.
At position 3 the compressor is located this is the part of the fridge that requires additional electricity to fulfil its function. The compressor pressurizes the now warmed gas that has taken on the excess heat from the fridge carbonate.
It then at position 4 passes as a hot highly pressurized gas into the radiator pipes located on the back of the fridge. As the pressurized gas passes through these long curved radiator pipes it quickly cools, returning to its liquid state and giving off heat during the process.
At position 5 the now cooled liquid that has given off the majority of its heat into the pipes and now returns through the insulation to repeat the process at the expansion valve.
So hopefully, via this explanation of a fridges function we can see that fridges aren’t creating cool, they’re merely moving the majority of heat within the fridge cabinets into the radiator pipes at the back of the fridge!
So what happens if you leave the fridge open, you may get a sudden blast of cold air as you open the fridge. But all you’ll achieve by leaving the fridge door open. Is your fridge compressor will have to work considerably harder to move coolant around the system keeping your fridge cool. All of the same heat will be returned into the room via the radiator pipes at the back of the fridge.
So if you really wanted to cool the room down, you would need a fridge where the radiator pipes are located outside of the room, rather than merely on the outside of the fridge. However, in doing this you have essentially invented an Air conditioning unit.
This is why fridges need to be incredibly well insulated, the worse the insulation, the harder the compressor will have to work to maintain the units cool temperature. This can become a huge electricity sink.
At Ben’s refrigeration, we pride ourselves on providing commercial refrigeration units that are incredibly well insulated and extremely efficient. Ben’s Refrigeration also provides a 24/7 emergency call out system in case any rare issues arise with refrigeration equipment that needs to be fixed by a skilled service engineer.
If you’re interested in commercial refrigeration call Ben’s Refrigeration on 0800 303 884
Or you can request a free no obligation quote on our Contact Page.