PDA

View Full Version : difference between flooded evaporator to d-x evaporator? pros and cons?







mjpaolo
17-03-2009, 04:24 AM
i'm ME student. just want to know the basics!

compresspec
17-03-2009, 10:46 AM
Hi Mipaolo,

Sorry, I am in hurry a little. :rolleyes: Just a few basics from my side.

A flooded ev is always filled half, usually two of tree parts of the vessel volume with liquid refrigerant. A DX-system evaporates always the complete refrigerant batch in the ev. Thatís the reason it is called dry expension.

On the one hand the refrigerant volume is much larger in a flooded system than in a DX one. On the other hand you can proceed with higher evaporating temps because the heat transfer to the liquid fluid is much better than to the gas in a DX system.

Unfortunately I have no English literature available. Maybe one of our native English guys can give you a suitable link.
Good luck with our studies. :D

Regards from Germany

US Iceman
17-03-2009, 02:18 PM
Flooded is a term which is abbreviated from gravity flooded. In these evaporators the liquid is flows by gravity through the evaporators. The liquid enters the bottom of the coil and flows though the tubes. As the liquid begins to evaporate the gas (being lighter than the liquid) rises and pulls some liquid with it. A portion of the liquid exits the evaporator and returns to a vessel called a surge drum. This vessel holds the liquid for the evaporator feed and also separates the liquid from the vapor. The vapor returns to the compressor. The oil has to be regularly drained from the surge drum.

A DX evaporator is a dry process. All of the liquid is evaporated in the evaporator. The thermostatic expansion valve controls the superheat (exiting the evaporator) to ensure a dry gas exits the evaporator. The oil is swept from the coil by the higher gas velocity.

mjpaolo
20-03-2009, 11:03 AM
thanks, i'm enlightened. Good day!