What effect do air or non-condensable gases have in a capillary tube system?

In a capillary tube system, the presence of air or non-condensable gases can lead to high suction and high discharge pressures. This is because these gases do not condense within the refrigerant circuit, which disrupts the normal phase changes of the refrigerant and impairs the heat exchange process.

When air or non-condensable gases enter the system, they essentially take up space in the evaporator and condenser. This results in an increase in pressure throughout the system since these gases are incompressible to the same extent as the refrigerant. Consequently, the suction line experiences elevated pressures due to the air or non-condensables not allowing the refrigerant to expand and absorb heat effectively. Simultaneously, higher discharge pressures occur in the condenser as the refrigerant struggles to release heat because the non-condensables prevent proper condensation, leading to an inefficient system operation.

Overall, the introduction of air or non-condensable gases in a capillary tube system causes a significant rise in both suction and discharge pressures, affecting the overall efficiency and performance of the air conditioning system.