What happens during superheating?

• A. The temperature remains constant
• B. The vapour is heated above its saturation temperature
• C. The refrigerant condenses fully
• D. The pressure increases dramatically

Answer: (B)

During superheating, the vapor is heated above its saturation temperature. In a refrigeration cycle, superheating occurs after the refrigerant has evaporated but before it enters the compressor. At this stage, the refrigerant exists as vapor and is subjected to additional heat, raising its temperature above the saturation point corresponding to its pressure.

This process is essential because it ensures that the refrigerant entering the compressor is entirely in the vapor state, preventing potential liquid refrigerant from damaging the compressor. Superheating increases the efficiency of the refrigeration cycle, as it allows for the extraction of more energy from the refrigerant before compression.

In this context, the other choices do not accurately describe what happens during superheating. The temperature does increase, thus eliminating the possibility of the temperature remaining constant. The refrigerant does not condense fully in superheating; instead, it remains in vapor form. Furthermore, while there may be a slight increase in pressure as the vapor is heated, it does not increase dramatically in the manner suggested. Therefore, the correct understanding of superheating lies in recognizing the process of raising the vapor temperature above its saturation point.