There is a lot of “Hot Air” associated with air compressors. First, there is the heat of compression, and the heat you feel when entering a compressor room, and the high temperature from radiation you feel when standing near an operating air compressor. An air compressor is a mechanical device that increases the pressure of a gas by reducing its volume. The amount of heat generated is dependent upon the final discharge pressure. Most single stage rotary screw air compressors have high air temperature shut down switches set at 240 F and operate in excess of 180 F to eliminate water. Many single and two stage piston compressors can have discharge temperature in excess of 300 F. This can all create a lot of “hot air”. This is not the “hot air” I am writing about. It is about the selling details and literature where the “hot air” blows. Compressor performance and subsequent sizing is many times sold on HP or CFM. The model number can also reflect HP or is it KW? Our European competitors size machines by KW, so a 5KW air compressor is really a 7 ½ HP machine. The model number may be SK-5. Beginning of the “hot air”. Next the performance sheets will show a maximum pressure of 125 PSI and an asterisk will state that full load performance was measured at 115 PSI. WHY? Hot Air. To convert KW to HP divide KW by .746. So a 5 KW machine at 115 PSI is 6.702 HP and more when operated at its maximum pressure. This misinformation can cause electrical service equipment to be too small or undersized or make a machine look more efficient than it is. Tricky and buyers beware. Maybe we should all learn from the VW diesel situation! As John Matarese says on Channel 5 news “Don’t waste your money”!
Hot Air & Compressors
