Which of the following best describes how a "positive displacement" compressor increases the pressure of a refrigerant?

A positive displacement compressor increases the pressure of a refrigerant primarily through the process of volume reduction. This type of compressor works by trapping a specific volume of refrigerant in a chamber, where it is then mechanically compressed to a smaller volume. By decreasing the volume of the refrigerant within that fixed space, the pressure increases according to Boyle's Law, which states that pressure and volume are inversely related in a closed system. As the volume decreases, the molecules of the refrigerant are pushed closer together, causing the pressure to rise.

This principle is fundamental to the operation of positive displacement compressors, such as reciprocating or rotary compressors, and is critical in refrigerant cycle systems used for cooling and HVAC applications. Understanding how these compressors function highlights their role in efficiently managing and transferring heat within refrigeration systems.