Customers looking to buy a new air compressor in the 5-15 kW power range are often faced with the dilemma of choosing between a reciprocating compressor and a rotary screw compressor.
According to Southern Cross Compressors Australia Pty Ltd , factors such as the amount of compressed air required and frequency of use, typically dictate the type of compressor suited to the specific application.
Rotary screw compressors
For instance, when compressed air is required for long durations of time, such as an entire shift, generally a rotary screw compressor would be best suited to the application. Rotary screw compressors perform at peak efficiency when run for long periods of time and are not suited to short periods of demand and long periods off duty. The majority of rotary screw compressors are oil lubricated - the warmer the compressor gets, the better the lubrication, and higher the efficiency.
Running a rotary screw compressor in short bursts can cause excessive wear and tear due to running cold, decreasing efficiency and increasing maintenance costs. Generally more expensive than reciprocating compressors, rotary screw compressors also come with advantages such as superior efficiency and can be programmed to turn off during breaks or at the end of the shift to avoid energy usage when no compressed air is required.
Reciprocating compressors are recommended for compressed air users that only require short periods of compressed air and have periods of 15 minutes or longer with no demand. Being air cooled, reciprocating compressors cannot run for long periods of time without risking overheating issues. Reciprocating compressors are recommended for short duration compressed air applications as they are generally cheaper and have lower maintenance costs.
Before selecting a reciprocating or rotary screw compressor for a specific application, it’s best to first analyse the facility’s compressed air usage profile to determine which compressor will provide the optimum balance of price, performance, efficiency and maintenance costs over the long term.