Hermetic cooling? Is Suction gas enough?

[The MG Pony]

Ok, I want to convert a display case into a water cooled system due to it being in the kitchen of a very hot restaurant. Now they have one all ready and it has a fan cooling the compressor, Now I think this is redundant being the compressors cool them selfs via suction gas.

So if I build the display case with a TXV and a properly sized Coaxial condenser with a V46AA-1C Valve to handle the flow, do I really need an additional fan for the compressor? Would not the suction gas be sufficient?

[ernestlin]

Hi, pony. If the suction gas temperature haven't been risen, and the volume of suction gas haven't been decreased, It's no problem. Because you use water cooled condensor, and the cooled efficiency become higher compared to air cooled type, the opening of TXV could be bigger at the same evaporating temperature/pressure. In a word, don't worry about that, but the pre-experiment is necessary. Hope it's useful.

[The MG Pony]

So basically hook a thermometer up to the compressor and see hot she gets during pull down and at load?

[ernestlin]

Yeah, it's a nice method. By observing the change of discharge gas temperature, you can judge if the winding's temperature is too high. But I miss an important factor of the compressor's cooling, the hemertic compressor is also cooled by the condensor's fan in the air cooled condensing unit, you should caculate this part.

[taz24]

[quote=So if I build the display case with a TXV and a properly sized Coaxial condenser with a V46AA-1C Valve to handle the flow, do I really need an additional fan for the compressor? Would not the suction gas be sufficient?[/quote]

Some hermetic comps are designed to be cooled by fan.
They mainly relly on the suction gas but some do need to befan cooled as well.
It will tell you on the comp label if it needs to be fan cooled.

taz.

[Electrocoolman]

Hi MG....sounds as if this is a commercial case....if so it will probably be 1/3 hp....normally anything above 1/6hp requires fan cooling.
As TAZ says...look on compressor...and then get data about compressor from manufacturer or wholesaler.
A fan is a lot cheaper than a seized compressor!

[The MG Pony]

lol indeed, A thought has occurred to me, if I replaced the compressor with a type that has an oil cooler I could rout a small amount of exhaust water through the cooling coil no? That would most certainly cool the compressor quite effectively and eliminate the fan all together!

I do believe I have some correct compressor! I'll look into that.

[ernestlin]

Hi, Pony, it's a brilliant thought..But, as taz and Eman said if the compressor is not big size (within the 1PH), it's not so necessary to replace by a compressor with oil cooler. After all, a fan is cheaper.