RAC Lecture 11 - Lesson 11 Vapour Compression Refrigeration...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Lesson 11 Vapour Compression Refrigeration Systems: Performance Aspects And Cycle Modifications Version 1 ME, IIT Kharagpur 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1. Performance aspects of SSS cycle and the effects of evaporator and condensing temperatures on system performance ( Section 11.1 ) 2. Modifications to the basic SSS cycle by way of subcooling and superheating and effects of these modifications on system performance ( Section 11.2.1 ) 3. Performance aspects of single stage VCRS cycle with Liquid-to-Suction Heat Exchanger and the concept of Grindley’s cycle ( Section 11.2.2 ) 4. Effect of superheat and criteria for optimum superheat ( Section 11.3 ) 5. Actual vapour compression refrigeration systems ( Section 11.4 ) 6. Complete vapour compression refrigeration systems ( Section 11.5 ) At the end of the lecture the student should be able to: 1. Show and discuss qualitatively the effects of evaporator and condensing temperatures on specific and volumic refrigeration effects, on specific and volumic work of compression and on system COP 2. Discuss and evaluate the performance of single stage VCRS with subcooling and superheating from given inputs and known refrigerant property data 3. Evaluate the performance of the system with a LSHX 4. Establish the existence of optimum superheat condition using Ewings-Gosney criteria 5. Evaluate the COP of actual VCRS from condensing and evaporator temperatures, efficiency of motor and compressor 6. Draw an actual VCRS cycle on T-s and P-h diagrams and discuss the effects of various irreversibilities due to pressure drops, heat transfer and non-ideal compression 7. Describe briefly a complete vapour compression refrigeration system 11.1. Performance of SSS cycle The performance of a standard VCRS cycle can be obtained by varying evaporator and condensing temperatures over the required range. Figure 11.1 shows the effects of evaporator and condensing temperatures on specific and volumic refrigeration effects of a standard VCRS cycle. As shown in the figure, for a given condenser temperature as evaporator temperature increases the specific refrigeration effect increases marginally. It can be seen that for a given evaporator temperature, the refrigeration effect decreases as condenser temperature increases. These trends can be explained easily with the help of the P-h diagram. It can also be observed that the volumetric refrigeration effect increases rapidly with evaporator temperature due to the increase in specific refrigeration effect and decrease in specific volume of refrigerant vapour at the inlet to the compressor. Volumetric refrigeration effect increases marginally as condenser temperature decreases. Version 1 ME, IIT Kharagpur
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/04/2010 for the course ME N/A taught by Professor N/a during the Spring '10 term at Indian Institute of Technology, Kharagpur.

Page1 / 22

RAC Lecture 11 - Lesson 11 Vapour Compression Refrigeration...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online