Discussion:
Questions for Discussion
Table 1. Coefficient of performance (COP)
Three COPs are based on Pe. Which one should be closer to COPTH , and why?
Which COP value should be provided to customers as the refrigerator specification, and why?
Table 2. Mass flow rate of refrigerant
What are the percentage differences between the three values?
Which is likely to be the most accurate one, and why?
Table 3. Efficiencies of the compressor
Examine the compressor suction and find the change in entropy after the compressor in one of the two tests. Does the entropy increase significantly? If it doesn’t, what implication has this regarding the efficiency of the compression process.
A typical value for the overall efficiency of a well lubricated compressor of this type could be about 60% and this would include a mechanical efficiency of about 90%. Could any likely errors in measurement account for the discrepancies between these values and those deduced from your measurements?
Other comments may include:
Overall energy balance between evaporator, condenser and compressor
Comparison of test 1 and test 2