A piston compressor, also known as a reciprocating compressor, is a type of positive displacement compressor that uses pistons driven by a crankshaft to deliver air at high pressure. This compressor operates through the back-and-forth motion of pistons in a cylinder, where gas is drawn into the cylinder during the piston's downward stroke and compressed during the upward stroke. They are commonly found in applications ranging from small-scale uses like air conditioning and refrigeration to large-scale industrial processes, such as in chemical plants and oil refineries.