Positive displacement compressor types include:

Positive displacement compressors are categorized based on their operating principles and mechanisms used to compress the gas. The types of compressors typically include reciprocating, rotary screw, gear, and diaphragm compressors. Each type operates by trapping a volume of air or gas and mechanically reducing its volume to increase pressure.

In the context of the question, the answer provided indicates the types of positive displacement compressors that are recognized and included in the selected answer. The selection emphasizes a variety of compressor mechanisms that are essential for applications requiring consistent gas flow and high-pressure output.

Reciprocating compressors, for example, are widely used due to their ability to handle large variations in pressure and are commonly found in both industrial and commercial applications. Rotary screw compressors, on the other hand, offer continuous flow and higher efficiency, making them suitable for larger scale operations.

The correct answer encompasses a combination of the mentioned types that align with the principles of positive displacement compression. This ensures that students have a clear understanding of the fundamental designs in compressor technology, critical for the operation of various mechanical systems in power engineering. Understanding these diverse types allows engineers to select the most appropriate compressor based on the specific requirements of a system, optimizing efficiency and performance.