need help for new systems in hot gas defrosting !!

[vimalmnn]

Hi guys,

Am new to this Ammonia refrigeration field.. The Hot gas defrosting that we are using having the following fault. Moisture is returning to the system with the suction. How it can be solved...???
Please advice the new effective methods that can be used in Ammonia refrigeration hot gas defrosting...
Expecting help from all !!!!

[US Iceman]

Moisture is returning to the system with the suction.

How do you know you have moisture returning to the system? And how is this related to hot gas defrost?

[keepitcool]

If you are talking about condensed refrigerant returning, this is normal. It should be returning to a suction accumulator. If you are talking about water I will echo US Iceman's question of how are the two related.

[icecube51]

i think its better to give some info about the plant build up,before there are answers given.

other wise its wild guessing, no ?

Ice

[TXiceman]

"Moisture is returning to the system with the suction. "

??? I am scratching my head on this one. Like noted, if you mean a wet suction, this is to be expected with a hot gas defrost. It should be returned to a suction accumulator or drum.

If you mean moisture into the room, during defrost...yes this will happen as well. You can cut the defrost temperature and try to avoid steamingt he moisture off the coil, but you will still have some moisture.

Ken

[vimalmnn]

Dear Ken.... What i meant is condensed refrigerant returning to the suction accumulator.. I know that, this is normal.. but how can i solve this problem....

[RANGER1]

vimalmnn,
The refrigerant is condensed in the evaporator .As the hot gas passes through the evaporator it melts ice and looses its heat in the process. A pressure regulating valve is set at a pressure/temp above 0 deg C/32 deg F (usually 515 kpa/75 psi) to be maintained in evap on defrost. Liquid refrigerant condensed will build up in unit and relieve into suction line when it exceeds pressure set on pressure regulating valve.

[US Iceman]

vimalmnn,

If you think is the normal way the system is supposed to operate, and you have asked this question...then you must have some other problems related to this.

What type of problems are you having?

Is the accumulator filling up with liquid?

[RANGER1]

Sorry, didnt read all posts.

[US Iceman]

Quite all right Ranger1. These sorts of posts take a while to sort out...

[Poodzy]

Is this causing you to flood out your compressors?
If so Try adjusting your controller to run a lower level.

Is the majority of the hot gas line ran in the freezer?

Another question that could be asked is how long between your defrosts? If the evaporators are completly plugged then they would be pushing back liquid already to your receiver.