Final answer:
Refrigerant migrates to the compressor in a refrigeration system due to the difference in temperatures. Smaller temperature differences result in more cost-effective operation of refrigerators, air conditioners, and heat pumps.
Step-by-step explanation:
In a refrigeration system, if the compressor crankcase is the coldest part of the system, refrigerant will migrate to the compressor because of the difference in temperatures in the system.
Refrigerators, air conditioners, and heat pumps are most cost-effective when there is a small difference between the temperatures of the hot and cold reservoirs. This is because the coefficient of performance (COP) of these systems is higher when the temperature difference is smaller, leading to more efficient operation.
For example, in a refrigerator, heat transfer occurs from air inside the unit (cold reservoir) to the surrounding air (hot reservoir) when the compressor crankcase is the coldest part. The difference in temperatures drives the refrigerant to migrate to the compressor, where it can extract heat from the colder air and exhaust it to the warmer surroundings.