Calculation Method of Specific Power of Air Compressor

The calculation method of the specific power of the air compressor is: specific power = input power ÷ displacement, where the unit of input power is kilowatts (kW), and the unit of displacement is cubic meters per minute (m & sup3;/min), the specific power unit of the calculation result is kW/(m³/min). This value represents the power consumed by the air compressor per 1 cubic meter of compressed air. The lower the value, the higher the energy efficiency of the air compressor and the more energy-saving the operation.

Input power it is the actual electric energy consumed by the air compressor during operation, which can be directly measured by the power analyzer or calculated by the following formula:

• input power of three-phase motor = & radic;3 × line voltage (V)× line current (A)× power factor ÷ 1000

air displacement it is the volume of compressed air output by the air compressor under specific working conditions (such as standard atmospheric pressure and temperature), which needs to be measured by a flowmeter and corrected to the value under standard working conditions according to the on-site temperature and pressure conditions. For example, if the on-site temperature is higher than the standard working condition, the measured displacement will be too large, and the specific power needs to be calculated after correction to ensure the accuracy of the data.

Air compressor without oil and water lubrication the specific power calculation principle is consistent with other types of air compressors, but it should be noted that:

• input power the total power consumption of the main motor and water lubrication system shall be included. Water lubrication systems reduce the temperature during compression by circulating water, reducing energy losses and potentially affecting overall energy efficiency.
• Air displacement during the correction, the influence of water lubrication on the air compression process shall be considered to ensure that the corrected value reflects the actual gas production capacity.

The meaning of calculating the specific power:

• assess energy efficiency the specific power is the core index to measure the economy of the air compressor. The lower the value, the lower the energy consumption per unit of gas production, and the long-term operation can significantly save electricity.
• Guide selection when choosing an air compressor, priority should be given to comparing the specific power, rather than just focusing on power or exhaust volume, to ensure that the equipment meets the gas demand while consuming the lowest energy.
• optimized operation: Regular monitoring of specific power can find that the equipment efficiency drops (such as filter element blockage, poor cooling), and timely maintenance to maintain efficient operation.

Precautions:

• measured input power: Avoid replacing the measured power with the rated power of the motor, otherwise it will cause the specific power to be too small and misjudge the energy efficiency of the equipment.
• Correction of displacement: Ignoring the influence of on-site temperature and pressure on the displacement will lead to distortion of the specific power calculation, and the revised standard displacement should be used.
• Comprehensive consideration: Low specific power does not represent actual energy saving, but also needs to be comprehensively evaluated in combination with factors such as equipment control mode and type selection matching degree.