Cooling within a refrigerator is based on a phenomenon known as the refrigeration cycle. In the simplest terms, chilling is the removal and transference of heat from one location to another. When an object is placed inside of a refrigerated space, the amount of heat inherent in the substance is reduced – and displaces outside of the cooled area.
So exactly how does this refrigeration cycle function? It consists of several concepts and processes that combined together power a modern fridge freezer. These concepts are outline below.
First of all, when you place an item in the refrigerator it contains more heat than the surrounding cooled air. Thru the physics of conduction, heat is drawn from the object – thus cooling it – and into the interior of the refrigerator – heating that air.
The actual refrigeration cycle is used to draw the heat that is added to that air back out of it, and transfer it outside of the cooled compartment. That cycle relies on the qualities of a refrigerant to move heat around.
One common refrigerant is Ammonia. Let us look at that as an example. A system with an Ammonia powered refrigeration cycle consists of four pieces; the condenser, the compressor, the evaporator and a measuring device.
The condenser functions by removing heat from a compressed gas – the refrigerant – and discarding it into the surrounding environment. As the refrigerant cools, the gas condenses into liquid form. This cooled liquid draws heat from the evaporator – which reheats the refrigerant and turns it back into a gas, while at the same time dropping the temperature of the air inside the refrigerator.
Most important of all is the compressor, it compresses the refrigerant gas thru the use of pistons. By pressuring the refrigerant, the gases saturation temperature is raised so that it can successfully absorb heat from the interior of the fridge.
To truly understand the refrigeration cycle takes some extensive study. The concepts behind it are not simple. If you are considering making a career of working with refrigerators, it is worth you taking the time to enroll in a refrigeration school or training program. This is the best way to learn the basics of the trade before entering an apprenticeship.