Energy Saving Methods For Air Compressors

How to save energy as much as possible while the air compressor is in operation is a hot topic of concern. Usually, the following methods can be adopted to achieve energy conservation:
1. Improve compressor efficiency
The use of current national first-class energy efficiency compressors to replace old compressors has improved the efficiency of compressors and reduced energy consumption. For example, using a two-stage compression screw compressor with dual heads instead of a single head screw compressor.
2. Using high-efficiency electric motors
The emergence of permanent magnet motors and high-efficiency motors has brought revolutionary changes to the energy-saving of electric motors. The efficiency of electric motors has increased from below 90% or even lower to over 93%, greatly saving the energy consumption of the motor itself.
3. Improve transmission efficiency
Air compressors often use V-belts to achieve transmission between the electric motor and the compressor. Although V-belts have advantages such as smooth transmission, it is usually necessary to choose a parallel connection of multiple tapes. Different tapes may have uneven loads due to uneven elasticity or errors in pulley grooves, which reduces transmission efficiency, wastes electricity, and also reduces the service life of V-belts. Choose high-quality and accurate pulleys and tapes. When the load is uneven, replace all tapes at once. Adjust the center distance carefully during installation to ensure that all tapes are subjected to the same tension, which can effectively improve their transmission efficiency. However, the use of V-belt transmission cannot completely eliminate energy loss in transmission. The use of a coaxial structure between the rotor and the motor can completely solve this problem, and it also increases air flow operation, achieving speed control throughout the entire range.
4. Reduce friction power consumption
The clearance size and lubrication situation between the rotor and cylinder affect the efficiency of the air compressor. Excessive clearance can cause air leakage loss, while too small clearance cannot form effective lubrication, increasing friction loss and increasing energy consumption of the air compressor. Effective lubrication can only be maintained with appropriate clearances. The measures to reduce friction power consumption include precision control of clearances, ensuring appropriate oil viscosity, rapid circulation, and regular maintenance. In addition, attention should be paid to changing lubricating oil according to seasonal and climatic changes, and low viscosity lubricating oil should be selected as much as possible under the premise of good lubrication performance.
5. Reduce pressure loss
The pneumatic system consists of an intake filter, intake valve, cooler, etc., which can transport compressed air to the equipment being used. If there are problems such as disrepair or improper repair of the intake valve, it will form air leakage, reduce the exhaust volume, and thus reduce the operating efficiency of the air compressor. To reduce pressure loss, the first step is to minimize the flow resistance and pressure loss of the pneumatic system while meeting the process requirements, such as installing fewer valves and shortening the suction pipeline as much as possible; Secondly, it is necessary to use a large diameter pneumatic system and a low-speed air supply method; Once again, it is necessary to reduce internal and external leaks of the equipment; High quality pneumatic components should be used, such as the intake valve should have good sealing performance and low resistance, and the air filter should choose a new type of ND filter, etc; Installation and daily management work should be done well, and regular inspections and maintenance should be carried out to ensure the safe and reliable operation of the pneumatic system.
6. Improve heat exchange performance and strengthen waste heat recovery
There are three types of compressed gases in air compressors: isothermal, adiabatic, and variable compression. Theoretically, isothermal compression has the lowest energy consumption, but in actual operation, it is variable compression. To reduce energy consumption during the compression process, it is necessary to improve cooling efficiency. There are intermediate and aftercoolers in the cooling water system, which can improve the performance of the intermediate cooler and make the secondary intake temperature closer to the temperature under isothermal compression, ensuring complete cooling. Lowering the temperature of cooling water, increasing flow rate, removing sediment from pipelines and equipment, and using water treatment agents to improve water quality can improve the performance of the cooler.
Reasonably configuring water pumps, controlling water consumption, reducing water loss, can effectively reduce power consumption. In an open cooling water system, energy is wasted in the form of heat. Strengthening waste heat recovery and adopting comprehensive waste heat utilization measures can achieve the goal of energy conservation. For example, introducing water into hot water supply such as bathrooms can achieve energy reuse. In a closed cooling water system, methods such as increasing the area of the circulating water tank can be used to accelerate the cooling rate of hot water, but the amount of cooling water should be controlled to avoid increasing the energy consumption of the circulating water pump.
7. Reactive power compensation energy-saving
Air compressors usually use asynchronous motors, and the power factor of asynchronous motors is relatively low, mostly between 0.2-0.85, which varies greatly with the change of load and results in high energy loss.
Reactive power compensation is to increase power factor and reduce energy loss under the premise of normal operation of the motor. Installing power capacitors at the receiving end can effectively improve power factor, especially suitable for low-voltage medium-sized motors that frequently operate continuously.
8. Variable frequency speed regulation energy-saving
Variable frequency speed regulation energy saving achieves motor speed regulation by installing a frequency converter between the power grid and the motor to change the voltage and motor frequency. By controlling the speed of the air compressor through a frequency converter, energy can be adjusted to meet the needs of light load operation and match the exhaust volume with the gas consumption. Through practice, it has been proven that the use of variable frequency speed regulation method can improve the work efficiency of air compressors under light load operation, reduce energy consumption of air compressors, and create better economic benefits for enterprises. The system controls the output pressure, connects the feedback signal to the frequency converter, compares it with the given signal, and after PID adjustment, sends the comprehensive signal to the input given end. The motor speed and power are adjusted according to the pressure change momentum.
9. Implement industrial computer and PLC joint control.
By using PLC technology to transform the air compressor group and achieve configuration control of all air compressor stations in the enterprise, it can achieve overall planning and balance of the enterprise's air compression system, use air compressor equipment more accurately, economically, and finely, achieve balance and optimization of the entire enterprise's gas consumption, and deeply eliminate energy waste. Large scale enterprises with multiple air compressor stations, different loads and operating conditions, as well as different qualities and operating habits of check-in personnel, inevitably lead to significant waste of electrical energy. These problems can only be ultimately solved through PLC linkage and group control of the air compressor. By implementing intelligent control, the air compression system can minimize the simple dependence on humans, operate more scientifically and reasonably, and set parameters such as the operating time, number of units, and working conditions of the air compressor as needed. This can optimize the working conditions of employees to a considerable extent, making the people-oriented approach more specific in our enterprise.
10. Application of advanced technology
The application of advanced technologies such as gas pipeline and process improvement, intelligent leak detection, variable flow control, energy-saving monitoring system, and cluster expert control system can also generate significant energy-saving benefits.