Refrigeration compressors are a particular type of compressor used for refrigeration, heat pumping, and air conditioning. Those compressors are large mechanical units, designed to be the core of industrial and air conditioning systems. Small, portable compressors do not fit into this category. You can also look for the best oil-lubricated air compressors (also known as "oljesmrjda luftkompressorer" in the Swedish Language).

Refrigeration compressors are designed to turn low-pressure gases into high-pressure and high-temperature gases. Additionally, technically speaking, they are also used to maintain a low boiling point. 

The first type of refrigeration compressor is the screw compressor. Screw compressors pass the refrigerant vapor through screw spindles. Each screw spindle compresses the intake of gas. Although there are refrigeration compressors with multiple spindles, most screw compressors have just two screw spindles.

The second type of refrigeration compressor is the scroll compressor. Scroll compressors achieve a lower rate of leakage and therefore are more efficient. They are the most common type of refrigeration compressors on the market.

The third type of refrigeration compressor is the piston compressor. These compressors achieve high-pressure levels and are mostly used for commercial purposes. Piston compressors are also known as reciprocating compressors.

Though other types of refrigeration compressors exist aside from the main three described above, they fit only very specific situations and are usually not very effective. These types are less common and their usage is very rare.

To sum it up, refrigeration compressors are large modules aimed at refrigeration, heart pumping, and air conditioning of large facilities. They should not be confused with small, stand-alone compressors.