Air (non-condensable gas) in an Ammonia system will NOT cause what?

In an ammonia refrigeration system, the presence of air, which is a non-condensable gas, can significantly affect the performance of the system. When air is introduced into the system, it generally contributes to issues such as increased discharge pressure, a rise in compression ratio, and decreased efficiency.

Lowering the suction pressure is not a consequence of having non-condensable gases like air in the system. Instead, the presence of these gases can disrupt the pressure dynamics. The air's low density and inability to condense under normal operating conditions lead to an increase in suction pressure rather than a decrease, as the compressor has to work harder to compress the mixed gases, effectively resulting in a suction pressure that is often higher than expected.

Thus, while non-condensable gases in a refrigeration system can lead to various problematic consequences, they do not lower the suction pressure. In fact, all the other consequences listed, such as a rise in discharge pressure, an increase in the compression ratio, and decreased efficiency, are directly associated with the presence of non-condensable gases like air in the ammonia system.