6 replies to this topic

[seth]

hello All;

During sizing of an air-cooled condenser coil, what is the typical or standard refrigerant velocity inside the tube so that i can determine the no. of pass per circuit as well as the minimum space required by the coil.

thanks,

seth

[chemtan]

hello All;

During sizing of an air-cooled condenser coil, what is the typical or standard refrigerant velocity inside the tube so that i can determine the no. of pass per circuit as well as the minimum space required by the coil.

thanks,

seth

Perhaps, a air cooled condenser would not require a refrigerant as the cooling medium is air.

Is there something that I did not understand here?

[seth]

Chemtan,

If you know the basic Vapor Compression cycle there are two types of condenser; one is Air-Cooled and the other one is watercooled. in that condenser, refrigerant is running inside a bank of copper tubes. the required no. of tubes in that condensers depends on the velocity of refrigerant coming out from the compressor. so i want to know what is this standard or typical refrigerant velocity.

Note: (This refrigerant is the condensing media).


Thanks,

seth

[chemtan]

Alright, so basically you are working a refrigeration system that employs a air cooled condeser.

"Air Cooled Condenser" is also the Fin-Fan HX normally employed to cool down tower top products - so I confused it with that one.

Anyways, back to your question... I could not find any material on this so apologies.. lets see if some one else has experience in this area and shares it.

[Jiten_process]

seth

you haven't mentioned type of refrigerant, flow, pressure condition etc. you even do not specify your allowable pressure drop across the condenser for refrigerant.

For condenser, velocity is not constant since inlet is vapor which is getting condensed over the tube length. I suggest if you are using any software for thermal design (e.g. HTRI) then it will give u best guidance through its help. velocity must be kept complying your allowable pressure drop and no vibration.

The other most useful resource is ASHRAE handbooks....which is a so called bible for refrigeration operation.

Good luck...

[srfish]

The two phase flow pattern should be examined. Ideally the flow pattern should be in annular flow where all of the tube wall has only a thin liquid layer. Annular flow will require a superficially gas velocity of 40 to 80 ft/sec. A heat transfer such as Shah could be used.

If annular flow gives too high of pressure drop then a correlation such as Chato could be used.

[seth]

Thank you very much, it seems that this 40 to 80 ft/sec is the velocity what i am asking for.

Thank you very much i can start now to calculate the possible size of an aircooled condenser.

Seth