Refrigeration compressors and air conditioning compressors provide air conditioning, heat pumping, and refrigeration for large-scale facilities and equipment. They compress low-pressure, low-volume gas into high-pressure and high-temperature gas. Refrigeration compressors and air conditioning compressors also remove vapor from the evaporator. Most refrigeration compressors (refrigerant compressors) are large, mechanical units that form the heart of industrial cooling systems or heating, ventilation, and air conditioning (HVAC) systems. Air conditioning compressors are also large-scale mechanical devices; however, these compressors are designed specifically for air conditioning systems and do not provide heating or ventilation functions.

There are three main categories of and air conditioning compressors: screw, scroll and piston. Screw compressors pass refrigerant vapor through screw spindles which compress the gas. Although most screw compressors have two spindles, products with three or more spindles are also available. Scroll compressors are the most common type of refrigerant compressor. They have a relatively low rate of leakage and provide high efficiency. Piston compressors or reciprocating compressors are specifically designed for industrial and commercial applications. They compress gases to high pressures and are designed for continuous operation. Other types of specialized refrigeration compressors and air conditioning compressors are also available. But, they are used only for very specific situations and are not very effective. These types are less common in use and are used very rarely.

Selecting refrigeration compressors and air conditioning compressors requires an analysis of refrigerant options and nominal cooling specifications. Refrigerant choices include R12, R13, R22, R134a, R404a, R407c, R502, and R507. There are four nominal cooling specifications to consider: capacity, input power, condensing temperature, and evaporative temperature. Capacity measures the ability of a refrigerant compressor to remove heat from the refrigerant gas. Nominal ratings are based on a standard set of conditions which include condensing temperature (CT), evaporative temperature (ET), refrigerant, and motor revolutions per minutes (rpm). Typically, refrigeration compressors and air conditioning compressors can run at many different values for these parameters, with corresponding changes in their cooling capacity.

The refrigeration compressors are large units which are specifically used for refrigeration, heat pumping, and for air conditioning of large facilities. These compressors should not be confused with small, stand alone compressors. Out of three types of refrigerating compressors are in use, the most efficient one is scroll compressors while reciprocating compressors are used for heavy industrial purpose.

From the above description, the reader would get some idea about refrigeration compressor and how they actually work.