Which of the following statements about evaporators is NOT true?

Which of the following statements about evaporators is NOT true?

• A. Low-pressure liquid enters the evaporator at the bottom.
• B. High-pressure vapor leaves the evaporator at the top.
• C. The evaporator is located underneath the dash.
• D. Air passing over the evaporator loses its heat to the cooler surface of the core.

Answer: (B)

The statement that high-pressure vapor leaves the evaporator at the top is not true. In an evaporator, the primary function is to absorb heat from the air and facilitate the phase change of refrigerant from a liquid to a vapor. As the low-pressure liquid refrigerant enters the evaporator, it absorbs heat and evaporates into a low-pressure vapor. This vapor, still at a low pressure, then exits the evaporator. The other statements are accurate regarding the operation and placement of an evaporator. Low-pressure liquid indeed enters the evaporator at the bottom where it begins to absorb heat. The statement about the evaporator being located underneath the dash is also correct, as this is a common position for evaporators in vehicle HVAC systems. Finally, when air passes over the evaporator coil, it indeed loses heat, allowing the refrigerant to absorb that heat and continue its cycle effectively.

The statement that high-pressure vapor leaves the evaporator at the top is not true. In an evaporator, the primary function is to absorb heat from the air and facilitate the phase change of refrigerant from a liquid to a vapor. As the low-pressure liquid refrigerant enters the evaporator, it absorbs heat and evaporates into a low-pressure vapor. This vapor, still at a low pressure, then exits the evaporator.

The other statements are accurate regarding the operation and placement of an evaporator. Low-pressure liquid indeed enters the evaporator at the bottom where it begins to absorb heat. The statement about the evaporator being located underneath the dash is also correct, as this is a common position for evaporators in vehicle HVAC systems. Finally, when air passes over the evaporator coil, it indeed loses heat, allowing the refrigerant to absorb that heat and continue its cycle effectively.