A refrigeration system operates using simple saturated cycle with a certain refrigerant. The condensing and evaporating temperatures for the refrigerant are 350C and –150C respectively. Determine the COP of the system. If a liquid vapour heat exchanger is installed in the system, with the temperature of the vapour leaving the heat exchanger at 150C, what will be the change in the COP?
Use the following data for the refrigerant used:
|
|
|
|
|
Superheated
|
|
|
|
|
|
20 K
|
40 K
|
|
t
|
hf
|
hg
|
sg
|
h
|
s
|
h
|
s
|
|
0C
35
–15
|
kJ/kg
69.5
-
|
kJ/kg
201.5
181.0
|
kJ/kg-K
0.6839
0.7052
|
kJ/kg
216.4
193.2
|
kJ/kg-K
0.731
0.751
|
kJ/kg
231.0
205.7
|
kJ/kg-K
0.7741
0.7942
|