Ask any of your friends what refrigeration is all about, and you are likely to get many interesting and widely varied answers. For some refrigeration has to do with keeping things cold. For some it has to do with keeping things frozen. And for others its just a necessary evil - with an outside impact on utility bills!.
What if I told you that refrigeration is actually all about heat? Keeping things cold or frozen is the subjective end goal, but the process is actually just moving heat from one "place" to another. From a scientific point of view, this whole topic would be termed thermodynamics - but lets keep things simple and understandable for the purposes of this discussion.
Heat is present in basically everything. Even a container of milk has heat. In refrigeration - particularly of foodstuffs - the goal is to keep that heat within a certain range that is equated with a "safe" temperature. A house is full of heat, we use refrigeration to keep that heat within a certain controlled range that is "comfortable". Comfortable might be the most subjective word I know! My wife thinks 80f is comfortable and I find 50f to be my ideal temperature. The struggle is real, but that's a whole other blog post ;-)
Refrigeration is possible because heat has an interesting and pretty fundamental habit - it deliberately moves where there is less heat present. Test this by opening your house up in the mid summer heat and see how fast the temperature rises inside. If your own summer heat is hardly any different than the temperature inside your house you will need to do something different... consider yourself lucky!
Perhaps a better example - in a refrigerated case storing containers of milk, we want to move some of the heat in the containers of milk to elsewhere in order to keep that milk in the "safe zone." In particular, we aim to recruit some of the heat in the milk to jump on the refrigeration express located in the refrigerators evaporator. The refrigerant circulating around the system is colder than the milk and we use air flow from fans to coax heat from the milk and carry the heat back to the evaporator. In a couple of steps, the heat in the milk joins the colder air heading and then gets transferred again into the refrigeration express. The heat gets absorbed by the refrigerant and heads on its way to the next stop on the refrigeration express - outside the cold case.
The heat from the milk is therefor ultimately moved from inside the refrigerator to outside - and released in a more desirable place, maybe above a rooftop or the side of a building where it transfers again into the atmosphere and away. So, through this little story, you can see that one perspective on the process of making things colder really is just about relocating the heat that they contain to another place.
The moral of the story - the next time your refrigerator is too warm, call the service team and ask for a certified heat transfer specialist. And, of course make sure you take a look at the Refrigeration Innovation range of Thermo-Simple color alerting thermometers and new SensorSimple wireless monitoring and alerting system to protect your home or business.
Until next time.
The Refrigeration Innovation Team