In a low-pressure chiller, where do air and other non-condensables typically collect?

• A. The bottom section of the condenser
• B. The evaporator
• C. The top section of the condenser
• D. The compressor

Answer: (C)

In a low-pressure chiller system, air and other non-condensables typically collect in the top section of the condenser. This occurs because these gases are less dense than the refrigerant vapor, causing them to rise within the condenser unit.

As the refrigerant vapor enters the condenser, it is cooled and condensed into a liquid. If non-condensables are present, they will accumulate at the highest point of the condenser where they cannot be condensed and expelled from the system. Allowing non-condensables to build up can lead to operational inefficiencies and safety concerns, so it's important to design the system to remove these gases through service ports or other means.

The other locations mentioned, such as the evaporator and the bottom section of the condenser, are not typical areas for non-condensables to collect. The evaporator is where the refrigerant absorbs heat, and the bottom of the condenser is where liquid refrigerant collects after being condensed. Non-condensables in those areas would disrupt the intended refrigeration cycle.