The term's domestic, commercial, and industrial refrigeration imply that they are separate and distinct areas of work. Unfortunately, like most things in life, it just isn't that simple. There is a large overlap between all three areas of refrigeration applications.
Commercial refrigeration is traditionally thought of as being concerned with the sale of food to the public. However, the role of the freezer, or preserver in the average home can be identical to a preserver in the corner shop.
When industrial refrigeration is mentioned many people tend to think of large coldstores and equipment, not processes such as liquification of gases, or liquid cooling, which are also industrial applications. Mention commercial, and the picture of a supermarket appears. Put simply, if the purpose of the refrigeration equipment has anything to do with foodstuffs, then it can be called commercial. The large food processing factory with blast freeze coldrooms, and compressors of many kilowatts, and the small freezer in the local off licence selling fish fingers, they are both commercial. The large articulated lorry transporting frozen food across the country, and the drinks chiller cooling your pint in the local pub are also commercial refrigeration applications.
Commercial refrigeration is the largest and most varied area of refrigeration. One way of seeing how varied the work is, is to take a look at the cold chain.
This is the journey of raw foodstuffs from the farm, or fishing vessel, etc. to the home, your dinner table!
All the above can accurately be classed as commercial. It would be ideal if the temperature of the product stayed constant throughout the chain, but in practice there is a rise of a few degrees at each link.