Hotgas defrost

[Peter_1]

Close pPicture of a hotgas defrost system we installed several years ago (Profroid)

[Andy]

Hi Peter,
any drawings to go with the photo.
Regards. Andy

[Peter_1]

Originally posted by Andy
Hi Peter,
any drawings to go with the photo.
Regards. Andy

I only found for the moment the original old drawing where I took some notices

[Peter_1]

Another one from Tasselli, a case manufacturer from Italy with whom I worked often in the past.

[Andy]

Hi Peter
on the Tasselli drawing is the extra coil and fan just to reduce the defrost hot gas temperature
And on the Profroid design is the extra plate a subcooler
Regards. Andy.

[Peter_1]

Originally posted by Andy
Hi Peter
on the Tasselli drawing is the extra coil and fan just to reduce the defrost hot gas temperature
And on the Profroid design is the extra plate a subcooler
Regards. Andy.

Hadn't noticed your reply Andy.

We never used the Tasselli drawing. As far as I understand the Italian language, it's a sort of subcooler for the returning condensate (when in defrosting mode) before putting it in the receiver.

Yes, in the Profroid is a subcooler for the liquid before sending it to the evaporators.

I installed in the first photo a small magnetic valve parallel over the big PM suction valve and did this to prevent large pressure shocks (equalise with the little one) after a defrosting cycle and to prevent massive liquid slugging. First the little one for some time and then the PM

[Mark C]

Hmmmm..... All I see is rubbatex water sponge insulation? Some Copper tubing.... Where's the beef?

[Peter_1]

Originally posted by Mark C
Hmmmm..... All I see is rubbatex water sponge insulation? Some Copper tubing.... Where's the beef?

Hi Mark,

did you found already some info concerning RETA?

Mark, it's Armaflex mu 7.000 (so very expensive sponges) but in earlier posts there were also schematics.

The more copper you should see, the more water and ice you should see.

I will try to make some nicer pictures of it but everything is situated underneath a roof where you can't stand up.

[Peter_1]

Originally posted by Marc O'Brien
I can't see it working this way.

It would seem to me rather a means to drain condensed vapour from the hotgas line into the common liquid line. If the condenser and receiver are higher than the evaporators then the hotgas pressure applied to the end of the liquid line would force a liquid column to develop back up the main liquid line toward the receiver. This would improve the quality of the liquid approaching the TEV's.

Is S30 a liquid line pressure suppression valve?

This schematic is used on all the Tasselli plants in Italy with cold gas defrost.
I never used it but they sended it to me some years ago.
We then used hot gas defrost.

S30 is according to the index a simple SV. Purpose of it???

Now you're saying it, I even don't see a departure on the receiver for the cold gas!?

I can ask for some clarfication at the engineers of Tasselli.