Some refrigeration systems will use a perfectly insulated ca

Some refrigeration systems will use a perfectly insulated capillary tube between the condenser and
the evaporator to reduce the refrigerant pressure. If the refrigerant enters the tube as a saturated
liquid at T 1 and exits at T 2 determine the quality at the tube outlet. Your answer must be fully in terms
of knowns – so you must explain how you would find all unknown but needed properties.

Solution

Capillary tube is one of the most commonly used throttling device in the refrigeration and air conditioning system.When the refrigerant leaves the condenser and enters the capillary tube its pressure drops down suddenly due to very small diameter of the capillary.In capillary the fall in pressure of the refrigerant takes place not due to orifice but due to small opening of the capillary.The decrease in pressure of the refrigerant through the capillary depends on the diameter of the capillary and the length of the capillary.Smaller is the diameter and more is the length of the capillary more is the drop in pressure of the refrigerant as it passes through it.