Refrigerant-134a enters the expansion valve of a refrigeration system at 120 psia as a saturated liquid and leaves at 20 psia. Determine the temperature and internal energy changes across the valve. Use data from the steam tables.

Solution :

Using the data table for refrigerant-134a at P = 120 psia

∴

For pressure, P = 20 psia

Change in temperature,

Now we find the quality,

The final energy,

Change in internal energy  

   = 38.09297-40.5485

  = -2.4556        

answer: 500 wph.

explanation:

answer:

a

explanation: