In regions with high ambient temperatures the choice of a good Oil-free Air-compressor is a challenge. When the temperature outdoor is 50 deg C (122 °F), in the compressor room (if any) the temperature can rise even higher.

 But even at 40 deg C (104°F), the lifetime of the Oil-free Air compressor is reducing very much ! 

 The solutions which are often used are Oil-free screw compressors or Oil-flooded for small capacities while centrifugals are used at larger flows.  

 At high temperatures, the Screw compressors often stop working with an expensive production stop of the factory as result.

The centrifugals can handle quite well the high ambient temperatures but performances will be vary.

The Oil-free rotaries have to be derated and often the compressor blocks fail after 1-2 years. 

The solution of Oil-flooded compressors for technical Oil-free air is often used as the alternative being more reliable. However, the filtration or separation of the oil is becoming very poor. The target of 2ppm for an oil-flooded compressor at those high temperatures cannot be achieved ! Every 7 deg C temperature increase the oil vapour content doubles ! At 40 deg C (104°C) the emission of oil is 8x higher than at 20deg C (68°F). Technical Oil-free through an Oil-flooded compressor with filtration is not a good idea for real Oil-free Air applications !

 The better solution, which can operate at those high temperatures, is the industrial slow running piston compressor. The industrial piston can handle high ambient temperatures, reliable and very energy efficient. 

 What's your best experience at these condities?