A rotary screw compressor is one that utilizes two intermeshing helical rotors to trap a volume of air, then compress it to a higher pressure. Rotary screw compressors can be run at lower temperatures for 24 hours per day, 365 days a year. The Maintenance and breakdown is very low in Screw Compressor.A piston compressor uses pistons driven by a crankshaft to deliver air at high pressure. The maintenance cost and breakdown time is higher.