Which of the following is a common example of a 'non-condensable' in a refrigeration system?

In a refrigeration system, non-condensables refer to gases that do not condense under the operating conditions of the system. Air or nitrogen is a common example of these non-condensables. When non-condensable gases are present, they can accumulate in the condenser, leading to decreased efficiency and a rise in pressure within the system. Unlike refrigerants such as R-404A and R-12, which are specifically designed to undergo phase transitions between liquid and gas states within the system, air and nitrogen do not interact with the refrigerant cycle in the same way. They remain in gaseous form and can disrupt the intended function of the system, making them significant in the context of refrigeration maintenance and troubleshooting. Understanding this concept helps technicians identify issues related to system performance and take appropriate corrective actions.