hello,
all of you,

i am junior thermal Designer and have some problem about subcooling & Desuperheating,
i know about what is subcooling & Desuperheating, but actually i have no idea about

(1) what is the effect of subcooling & Desuperheating and why it is required?,
and what is its effect on performance of condenser,

(2) what is the meaning of delta t in condenser design parameters it is in terms of air or related to refrigerant? pls....Explained

 

Hi,

Has been a few years now since I have done this stuff so take this with a pinch of salt but should get you in the right direction.

The best way to describe subcooling is in a graph:



Subcooling is done between the condenser and the expansion valve. It is done in a subcooler which is basically a heat exchanger. You put the condensed refrigerant through a heat exchanger and cool it down by using an offshoot from the main refrigerant line between the condenser and subcooler. You put this offshoot refrigerant through an expansion valve and use that too cool down the main flow of refrigerant.



Now you have supercooled liquid that when you expand has actually more "cooling potential" in the evaporators as there is more liquid to evaporate (note in general when you put the refrigerant through an expansion valve there is always going to be some liquid that turns to "flash" gas which cant be used in the evaporator, a subcooler reduces the amount of "flash" gas and increases the amount of liquid which is actually useful).

As for when it is used, I am a bit merky on that now but I remember at the ice cream factor I worked at they had a main refrigeration system for the ice cream making process and another for the coolstores. The coolstore refrigeration system wasn't as efficient/too small so I think subcooling the refrigerant helped to boost the efficiency/range of the system. Haze has crept into this paragraph but hope that helps.

Oh, and the refrigerant that was being used was ammonia.

Hayden

 

...and I need a lesson on how to post pictures up from file

 

Hi Gareth,

What are the guidelines? Isn't the best description so would require a bit of ironing out etc. Will see how I go.

Cheers,
Hayden