If evaporator pressure is reduced at the expansion valve, what is the result for the refrigerant?

When the evaporator pressure is reduced at the expansion valve, the boiling point of the refrigerant decreases. This is due to the relationship between pressure and boiling point in liquids and gases.

In simple terms, the boiling point of a substance is the temperature at which its vapor pressure equals the surrounding pressure. When the pressure is lowered in the evaporator, it allows the refrigerant to boil at a lower temperature. This principle is essential in refrigeration cycles, where a refrigerant must evaporate to absorb heat from its surroundings.

By reducing the evaporator pressure, the refrigerant can effectively vaporize at lower temperatures, which enhances the heat absorption capabilities of the system, improving its efficiency. Lower boiling points facilitate energy transfer, making the refrigeration process more effective, especially under varying load conditions. This is a fundamental concept in thermodynamics that governs the behavior of refrigerants in cooling systems.