How exactly does a refrigerator work?
When I started working on appliances, one of the first things I wanted to know was how exactly everything worked. I operated under the idea that if you could fully understand a system, you could understand where and why things fail and be able to more accurately diagnose problems and repair things. This turned out to be a great foundation and the logic holds true. So how exactly does a refrigerator work? Read on and I'll do my best to explain.
When thinking about a refrigerator, most people think it makes things cold, which is true, but not the whole story. The first thing to think about is what is cold? Cold is the absence of heat, and heat is a form of energy. According to the first law of thermodynamics energy cannot be created or destroyed, it can only change from one form to another. So if there's heat inside a refrigerator, you can't just get rid of it, but you can put it somewhere else. This is where the magic of modern refrigeration happens. It uses a system of airflow along with boiling and condensing gas to trap the heat and move it elsewhere.
I always think of the way a refrigerator cools with an analogy. Imagine your child has a messy room. Toys everywhere, clothes strewn about, the works. You tell them to clean up the mess. Being a child, they do what any kid would do and shove everything under the bed and call it a day. The mess is still there, it's just out of sight. This is essentially how a refrigerator operates. It takes the heat from inside the refrigerator and moves it into the surrounding room where it's no longer a problem.
Obviously it's a bit more complicated than that, but that's a good starting point. So you may be asking how it moves the heat from inside to outside. Great question! There are several critical components to almost any refrigeration system. The compressor, evaporator, condenser, drier, capillary tube, evaporator fan, and the refrigerant. The way I remember the functions of each component is that they largely give it away in the name. For instance, what does a compressor do? It compresses! What about the evaporator? You guessed it, it evaporates.
So here's the whole process. The compressor compresses the refrigerant and pushes it through the condenser, where it condenses into a liquid state. From there it filters through the drier which removes moisture and it continues on into the capillary tube. Once in the capillary tube it travels into the evaporator where it goes from a small tube and high pressure to a larger tube with lower pressure. This causes the refrigerant to boil and expand into a gas again, where it makes it's way back to the compressor to restart the whole process. During this exchange there are typically fans blowing across the condenser and evaporator to help move the heat or lack thereof around, taking the heat from inside the unit to outside.
Obviously, this is the broadest of overviews and there are many systems that get more complicated, especially when you get into units that have an evaporator in the freezer and refrigerator (dual evaporator) or other systems that have 3 evaporators. This adds more parts like valves that change the flow of refrigerant or specialized tubing with check valves to prevent backflow, but even with those, the basic idea is the same. Gas goes through the system, changing states of matter to take heat from one place to another. Most modern refrigerators also have an automated defrost cycle to remove frost buildup on the evaporator, so you don't have to manually defrost like in the days of old.
So why is all this important? For most folks, it's probably not, and you'll likely never need to know all this. It may score you an answer at a trivia night if you're lucky. For repairmen like myself, it's critical to know not only how this system operates, but also how to fix it when it's not. When thermal exchange isn't happening correctly we have to find the cause and accurately diagnose and fix the issue, so it's very important to understand how things are supposed to work so you can tell where things have gone awry.
At Ken's Appliance Service, we deal with refrigeration issues every day. While we do warranty work for Whirlpool and their family of brands, we also service many other brands out of warranty. We are located at 511B Middle Tennessee Blvd on Murfreesboro, but service across all of Middle Tennessee as well as Chattanooga and Memphis. Having appliance trouble? Give us a call at 615-896-2933 or use the link below to schedule an appointment. Feel like fixing it yourself? We also sell parts and have a large inventory in our warehouse!
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