Point of view about subcooling

[A.Mortezania]

Dear Friends,
Would you please help me to solve this problem ?

View 1 :
Regarding sub-cooling, When I see different sources I see we should read discharge pressure then get saturation temperature from discharge pressure (T1), Also get liquid line temperature after condenser (T2) , Sub-cooling = T1 – T2.

View 2 :
But when I see SPORLAN documents (Photo below) , SPORLAN says as you know pressure at inlet of condenser is different with condenser outlet and at condenser we have pressure lost. By this while we want to measure sub-cooling we should get saturation pressure of receiver tank to know saturation temp. Also measure liquid line temperature. Decrease these two temp. form each other to get sub-cooling.

15280




Please share your opinion with me.

Sincerely yours.

[Brian_UK]

Regarding view 1 and view 2, these are two different piping schemes, both are correct.

However if you work through the Sporlan scheme you will see that the condenser is giving 5° subcooling and the receiver is adding an additional 5° subcooling so making a 10° subcooling across the condenser/receiver combination.

Remember that site conditions often decide how the readings will be taken. It is unlikely that there will be pressure tapping points after every component like that of a laboratory test rig.

[Segei]

To determine correct subcooling pressure and temperature should be measured at the same point. For view 1 assumption is that no pressure drop in the condenser. It means discharge pressure is the same as receiver pressure. For shown piping it is not correct. So SPORLAN is right. However, if we add equalizing line between discharge and receiver, receiver pressure will be 158 psig and view 1 will be right.