Cool Gas Defrosting

[jwasir]

Does any one has experiance with Cool Gas defrosting?

Thanks!

[smpsmp45]

Though I have seen the theory part of it. I do not know anyone using this system yet.
May be the Europe is using this system

[chemi-cool]

Hi jwasir,

I have copied for you a short article about cool gas defrost,

"A system for refrigerating food products utilizes a saturated gaseous refrigerant, commonly called "cool gas" for defrosting an evaporator or set of evaporators. When defrost is to occur, the saturated gaseous refrigerant flows from a receiver through the evaporator or set thereof being defrosted. A differential pressure control switch operates to prevent flow of refrigerant to the receiver from the liquid supply line through which said refrigerant normally flows from the condenser to the evaporators. The flow from the liquid line to the receiver is prevented whenever the pressure in the liquid line exceeds the pressure in the receiver by a predetermined value. Accordingly, if liquid in the receiver is fully evaporated in providing saturated gaseous refrigerant for defrost purposes, and the pressure in the receiver is less than in the liquid line and causes the flow of liquid from the liquid line to the receiver to be closed off by operation of the differential pressure switch, the defrosting operation switches automatically from cool to hot gas as a response to the depletion of the cool gas supply"

[jwasir]

Thanks Chemi-Cool,

Have ever employed the method?

[Goober]

It's a dog of a system. I'm no designer and am but a well grounded tradesman and I have worked on them. You cannot beat electric defrost.

[ntfreezer]

I have been built a cool gas defrost system in Purth of Australia one year ago. It works very well.

[ntfreezer]

I have been built a cool gas defrost system in Purth of Australia one year ago. It works very well.
If someone have interests, please sent your emails to me, and I can sent some pictures to your email.

[jwasir]

Kindly send the pics and drgs, if possible at jdwasir@kooljet.com

[icecube51]

i would like to see the drawings or specs to please.
info@voficecube.be

thnx, Ice

[Refrigerologist]

We used to operate a cool gas defrost system at a branch of Safeway's. It worked very well, and did not cause as many problems as hot gas defrost.

It stopped the sudden collapsing of return bends on evaporators that sometimes occured on low temp applications. This phenomena was caused by the sudden changes in temperatures and pressures associated with hot gas defrost (and the crushing effect of ice build up wouldn't help:D).

The set up is almost identical to a hot gas system, but with saturated gas being taken from the top of the receiver, of which there is a constant supply. In fact a set of isolation valves were installed on the packs so that it could be switched form cool to hot gas or vice verce.

Defrost times appeared to be similar to hot gas, although if I had a severe ice up, I used to open the hot gas isolation valves and dump the hot gas into the evaportors to clear them!

[taz24]

Does any one has experiance with Cool Gas defrosting?

Thanks!

A lot of the supermarket packs from the 80's and 90's
had hot gas defrost or change the valves around and then cool gas defrost.

The only one big advantage it has in my opinion is the stress to the pipework is less with cool gas than it is with hot gas.
I have seen pipe runs expand 10cm (3 or 4 inch) when they went from refrigeration to defrost on hot gas and it can fracture elbows if not installed correctly.

They take a bit more setting up and the differential over the A8 valve needs to be closely controlled.
Once set up though, it is said to be a bit more cost efficient.

But you can't beat hot gas for clearing the coil.

taz.