Lesson NPTEL（NPTEL课）.pdfVIP

Lesson 18 Refrigeration System Components: Compressors Version 1 ME, IIT Kharagpur 1 The objectives of this lesson are to: 1. Discuss basic components of a vapour compression refrigeration system (Section 18.1) 2. Present classification of refrigerant compressors based on working principle and based on the arrangement of compressor motor or external drive (Section 18.2.1) 3. Describe the working principle of reciprocating compressors (Section 18.3) 4. Discuss the performance aspects of ideal reciprocating compressors with and without clearance (Section 18.3.1) At the end of the lesson, the student should be able to: 1. List important components of a vapour compression refrigeration system 2. Classify refrigerant compressors based on their working principle and based on the arrangement of compressor motor/external drive 3. Enumerate salient features of positive displacement type compressors, dynamic compressors, open and hermetic compressors 4. Draw the schematic of a reciprocating compressor and explain its working principle 5. Define an ideal reciprocating compressor without clearance using pressure-volume and pressure-crank angle diagrams 6. Calculate the required displacement rate and power input of an ideal compressor without clearance 7. Define an ideal reciprocating compressor with clearance using pressure- volume and pressure-crank angle diagrams 8. Calculate the volumetric efficiency and power input of an ideal compressor with clearance, and 9. Discuss the effects of compression ratio and index of compression on the