Question

The evaporator which is commonly used in packaged air conditioner is

• A. Finned evaporator
• B. Plate surface evaporator
• C. Bare-tube evaporator
• D. Both (B) and (C)

Hint:

Fins add surface area for air-side heat transfer, which suits compact air conditioning units.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
An evaporator takes heat from the air or liquid being cooled. Types include bare-tube, plate surface and finned evaporators.

Step 2: Key Approach:
A packaged air conditioner cools air, and air is a poor conductor of heat. So the evaporator must have a large surface area on the air side.

Step 3: Detailed Explanation:
A finned evaporator has thin metal fins fixed on the tubes.
The fins increase the surface area that touches the air a great deal.
A fan blows the room air over the fins, and heat moves quickly into the cold refrigerant.
This keeps the evaporator compact, so it is used in packaged, split and window air conditioners.

Step 4: Why the other options are wrong.
Plate surface evaporators are used in domestic refrigerators and freezers.
Bare-tube evaporators are used for cooling liquids and in cold rooms where frost builds up.
Option (D) is wrong because (B) and (C) are both not the common choice here.

Final Answer:
Packaged air conditioners commonly use the finned evaporator. This is option (A).