I have replaced noisy 115VAC fans with 12VDC Noiseblocker Black Silent Pro PL-2 fans from Germany. For my 140S, I bought a 120mm but they have other sizes. There is a retailer in Ireland that ships to the EU rather easily:

The fan is thinner than the original which made installation a bit easier. The caveat is you will need to create a small board to convert the 115VAC to 12VDC using four 1N4007, four 1/2W resistors to halve the voltage twice 110 -> 55 -> 27.5 to meet the upper threshold of the 7812, and a 1uF 35V electrolytic filter capacitor. The fan is so silent one can hear the subtle buzzing of the transformer. I opted to construct two aluminum 90-degree bends from the upper pair of fan-transistor plane bolts to attach the circuitboard parallel such that it was under the level of the cover.

I also had to make some custom bolts from a longer piece of M4 from a Bauhaus to attach the cooling planes for the four power transistors - also with some M4 washers, etc because of the difference between SAE and metric. The result is very nice but I had to run the fan from an external battery while testing/building the conversion circuit to keep the transistors cool.

You can get the datasheet from here:

Christopher