• Support PF! Buy your school textbooks, materials and every day products Here!

Expansion valve question

  • Thread starter zzinfinity
  • Start date
  • #1
47
0

Homework Statement


Refrigerant 134-a enters the expansion valve of a refrigeration system at 160 psia as a saturated liquid and leaves at 30 psia. Determine the temperature and internal energy changes across the valve.


Homework Equations



Δu=cv*ΔT

The Attempt at a Solution



I'm not sure how to get the temperature change. Since we know it is initially a saturated liquid, I was able to get the initial temperature from a property table to be 109.5 °F

Is there a way to tell if the refrigerant is a saturated mixture or a superheated vapor after the pressure change? Can we assume its a saturated mixture?
 

Answers and Replies

  • #2
1,198
5
Hint: Is there any work being done? Think first law for a flow situation.
 

Related Threads for: Expansion valve question

  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
3
Views
3K
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
0
Views
947
  • Last Post
Replies
1
Views
12K
  • Last Post
Replies
1
Views
1K
Replies
1
Views
3K
Replies
1
Views
358
Top