Final answer:
Hermetic compressors in recycling or recovery equipment can overheat under deep vacuum due to insufficient refrigerant flow for cooling, and less effective heat transfer because of the lower density of air or other substances to absorb the generated heat.
Step-by-step explanation:
Recycling or recovery equipment using hermetic compressors can overheat when drawing deep vacuums because the compressor depends on the refrigerant flowing through it for cooling. Removing the refrigerant to create a vacuum can lead to insufficient cooling of the compressor. Furthermore, under deep vacuum conditions, heat transfer from the electrically driven compressor's work is less effective because there is less air (or other substances) to absorb the heat generated by compressing the gas. This may cause the temperature of the compressor to rise, thus increasing the risk of overheating.