Silent Fridge

I stay in an apartment above the store bottle and its cooling fan is noisy

Find the fan code, serial number and manufacturer. Phone and ask them if they make a silent fan for this unit. Fan silencers can reduce noise output for a supply up to 25% fanusually. Apart from that you could try to get an acoustic box fan mounted outside the fan, thereby helping to reduce noise, but not as much as the muffler. Hope this helps.

an oil of lubricating oil.

Oil It!

It is more likely that the engine makes noise, not the fan blades themselves. If so, you're screwed. The only way to fix this is to replace the engine with a quieter version.

Since this is a commercial engine, they are not made for calm, but for sure, long-term operation.

It could also be the speed of rotation of the engine as well. The faseter it turns, the stronger it is. If it has a speed setting different, try turning it down to a lower setting. Again, replace it with a larger fan that spins slowly will reduce the noise.

This is not the fan, but the refrigerator THAT'S NOISY U ONLY thing to do is isolate the floor

The noise is probably the rubber hum and vibration of the compressor ... if you look inside, you should see up / washers / rings or something that helps to keep the compressor in place. Replace / update what's in there with the new / thicker rubber to isolate vibration.

Is the unit normal and noisy OR IS NOISY MARKET ABNORMALLY because something is wrong? FOR EXAMPLE, you say the fan blade is hitting the hood and if it were adjusted MAKING IT quit this racket?