1. The inverter consumes 3% of power. When the motor deviates from the rated power and rated speed, the efficiency decreases. When the screw compressor speed deviates from the rated speed, the optimal oil-gas mixing ratio is destroyed and the efficiency also decreases. Therefore, when using a variable frequency screw compressor, although the gas output is continuously equal to the gas consumption of the pipeline network, the power used to produce each cubic meter of compressed air increases. In other words, under continuous loading conditions, variable frequency screw compressors do not save energy.
2. In most screw compressor use cases, the gas consumption of the pipeline network is constantly changing, and the gas output of the compressor cannot be constantly equal to the gas consumption of the pipeline network. When the pipeline network pressure is equal to the set value, the screw compressor enters the no-load state. The screw compressor consumes 30% to 40% of the rated power of the motor when idling, so the efficiency of the screw compressor is low when idling. Reducing the idling time or preventing the screw compressor from entering the idling state has a certain energy-saving effect.
3. The variable frequency screw compressor can effectively reduce the idling time or prevent the screw compressor from entering the idling state, so when the rated gas output of the compressor is greater than the gas consumption of the pipeline network, the variable frequency screw compressor has a certain energy-saving effect.
4. The variable frequency screw compressor is effective in stabilizing the pipeline network pressure, and can stabilize the pipeline network pressure within the range of ±0.01MPa-this is not easy to achieve with other flow control methods.