How much ice is allowed on a compressor?

How much ice is allowed on a compressor? | Ask an Expert

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@hvacae6904 3 жыл бұрын

I have a refrigeration plant for freezer application using r 22 as a refrigerant is it normal to build up an ice on compressor body? I hope you notice and thanks

@DanfossClimate 3 жыл бұрын

Hi, Thank you for your comment. When evaporating below zero deg.C for a freezer, in the region of -24 deg.C for a room temperature -18 deg.C, the suction gas back to the compressor will be below Zero deg.C. It is normal to have an ice build-up on the suction valve, but not the compressor body. You need to measure the suction superheat to find if the suction gas to the compressor is the correct temperature. Too much suction superheat and you risk high discharge temperatures or too low, and you risk liquid returning to the compressor. In both cases, it will cause compressor failure. A freezer room at -18 deg.C temperature would evaporate at -24deg.C. The Evaporator superheat would be 8 Kelvin, meaning the suction gas leaving the evaporator should be -16 deg.C. The heat picked up in the suction line coming back to the compressor is dependent on the length of pipe, ambient temperature, and thickness of the pipe insulation and integrity. It would be expected the temperature on the suction valve of the compressor to be about - 8 deg.C. Ice on the compressor body means that the suction superheat is too low. Hope this was helpful :-)

@tanusharma681 4 жыл бұрын

Sir we always use danfoss Expansion Valve but at some place we want to reduce the cost of the machinery so we want to use capillary tube but there was a big problem arises we don't know what is the formula to calculate the size of capillary tube according to the temperature that we want ? Please sir make a video on this.

@chinhduy 4 жыл бұрын

I design a system with MTZ-40 compressor, using thermo expansion valve R404a -40 / 10. The ice would cover all the compressor after a few minutes running. What could I do abount that?

@DanfossClimate 4 жыл бұрын

Please check the superheat on the evaporator which should be about 8 kelvin, then please check the suction superheat back at the compressor suction valve. If you are evaporating at -40deg.C, then I would expect the temperature at the compressor suction valve to be in the region -20 deg.C. If the ice is covering the whole of the compressor you can increase the superheat on the expansion valve to reduce this. However you also need to check the discharge temperature to ensure it is not getting too warm because the greater the suction superheat, the greater the discharge temperature. I would expect a discharge temperature around 85 deg.C - John

@shuaib8908 2 жыл бұрын

Hi there, can you use a coolroom compressor for a freezer application?? And what if they are the same KW, would this make a difference??

@Will-ce7tv 5 ай бұрын

Won't an EPR ensure it doesn't freeze up?

@DanfossClimate 5 ай бұрын

Hi, we are checking with our experts and will get back to you.

@DanfossClimate 5 ай бұрын

Hi Will. Yes an EPR (evaporator pressure regulator) will maintain a set stable evaporator temperature in the evaporator, normally used if you need a precise evaporating temperature and humidity for the refrigerated goods or if you have more than one evaporator on a system in which one evaporator needs to evaporate at a higher suction pressure than the other one. However, you would still need to set up the expansion device to maintain the correct level of superheat and control suction superheat level with correct level of insulation etc. If you just want to control the pressure that the compressor is getting from the suction side then use a CPR (crankcase pressure regulator) for example in a blast chill application were the load in the cold-room is high at the beginning of the cycle you would control the suction pressure so as not to overload the compressor motor. We hope this answers your question!