What property of oil contributes to its gathering in the evaporator?

The property of oil that contributes to its gathering in the evaporator is related to oil's high boiling point. In the context of an ammonia refrigeration system, the evaporator is where refrigerant collects heat and changes from a liquid to a gas, operating at lower temperatures. Since oil often has a higher boiling point than the refrigerant, it remains in a liquid state, preventing it from vaporizing and thus accumulating in the evaporator. This accumulation can lead to issues such as reduced efficiency and potential flooding, as the oil can obstruct the flow of refrigerant and impede effective heat exchange.

Understanding the boiling point is crucial because it indicates the temperature at which a substance transitions from liquid to gas. In a refrigeration system, maintaining appropriate oil levels and ensuring it does not excessively accumulate in low-temperature regions like the evaporator is essential for the system's efficiency and performance.