Which type of compressor uses pistons to compress refrigerant gas?

The type of compressor that uses pistons to compress refrigerant gas is the reciprocating compressor. This type of compressor operates through a piston-driven mechanism that cycles within a cylinder. As the piston moves down, it creates a vacuum that allows refrigerant gas to enter the cylinder. When the piston moves up, it compresses the gas, raising its pressure before it is expelled through the discharge valve.

Reciprocating compressors are commonly used in various refrigeration and air conditioning applications due to their ability to handle high pressures and be effective across different load conditions. They are characterized by their robust design and can vary in configuration, including single-stage and multi-stage designs to achieve different compression ratios.

Other compressor types, while also effective in their own ways, operate on different principles. For instance, scroll compressors utilize two spiral elements to compress the refrigerant, rotary compressors rely on rotors to compress gas, and centrifugal compressors use a rotating impeller to increase the velocity of the refrigerant and convert that velocity into pressure. Each type has its own advantages and application areas but none utilize pistons in the same manner as reciprocating compressors.