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View Full Version : Brazed plate heat echanger as subcooler



subcooler
20-11-2007, 12:17 AM
HI Guys

I was wandering if you guys have any problem controlling floodback especially when outside temp is very low. I know that they must use a perforated tube as a distributor on the dx side of the subcooler but not all of them are using it.

The MG Pony
20-11-2007, 02:51 AM
who, what, where, when & why?

Details my friend details, they make the world go round! And they make questions make sense!

subcooler
20-11-2007, 08:56 PM
Details: Often supermarkets are using Med temp rack to subcooled liquid temp on LTemp rack by using a brazed plate heat exchanger. I often hear from technicians that when the condensing temperature is very low (let say 40F and less), the superheat at the outlet was difficult to maintain...it's hunting to a point that temporarily flood back happen. I was wandering if in England you guys see this happening.

Truly

750 Valve
27-11-2007, 11:02 AM
Don't know about the pommes but I see that in Aus, its got a lot to do with the changing liquid line flow rates thru the heat exchanger. A 2 TXV setup is an option you may look into, a danfoss akc55 or 255 has a two valve control option inbuilt.
If you have a majority of the cases on the system running on sst and not cycling it is not as noticable as the flow rates are somewhat stable. Be sure not to shut off too much to defrost at once as well.
And as you point out, lower ambients and floating heads will also make setting these up tedious, i like to limit the float on these setups.