The equipment consumes 350 liters of compressed air per minute. How can the cost of this compressed air be calculated?

I. Clarify Basic Data and Unit Conversions

To calculate the cost of compressed air, you must first convert the equipment’s air consumption into a standardized unit of measurement. The equipment’s air consumption is known to be 350 liters per minute (L/min).

• Minute gas consumption: 350 L/min = 0.35 cubic meters per minute (m³/min).
• Hourly gas consumption: 0.35 m³/min × 60 minutes = 21 cubic meters per hour (m³/h).

This means that, under full-load continuous operation, the equipment consumes 21 cubic meters of compressed air per hour.

II. Calculation of the production cost per cubic meter of compressed air

The cost of compressed air is primarily driven by the electrical energy consumed during compressor operation. To calculate the gas‑consumption cost of a piece of equipment, it is first necessary to determine the total electricity cost per cubic meter of compressed air.

The calculation formula is:Cost of producing gas per cubic meter = Compressor input power (kW) ÷ Actual air compressor output (m³/min) × 60 ÷ electricity price (yuan/kWh).

In real-world industrial settings, since air compressors of different energy efficiency classes exhibit varying gas‑production efficiencies, companies can calculate the actual electricity consumption per cubic meter of compressed air by using either the compressor’s nameplate data or its operational meter readings. By factoring in local industrial electricity rates, they can then determine the basic manufacturing cost per cubic meter of compressed air.

III. Direct Gas Costs of Computing Equipment

Once the cost per cubic meter of compressed air has been determined, the equipment’s direct air‑consumption costs can be calculated.

Hourly direct gas consumption cost = Equipment’s hourly gas consumption (m³/h) × Cost per cubic meter of compressed air (CNY/ m³).

Taking an hourly air consumption of 21 cubic meters as an example, multiply the known all‑inclusive cost per cubic meter of compressed air by 21 to determine the equipment’s direct compressed‑air cost per hour. Then, multiply this figure by the equipment’s average daily operating hours and its average monthly working days to calculate the monthly or annual direct energy‑consumption cost.

IV. Assessing Hidden Costs and Identifying Optimization Opportunities

In addition to direct electricity costs, the total cost of ownership of a compressed air system includes other hidden expenses. When conducting a comprehensive cost analysis, it is advisable to take the following factors into account:

• Pipeline network leakage losses: Leakage of compressed air during transmission can result in the actual gas production exceeding the equipment’s actual consumption; the electricity cost associated with this loss should be allocated to the consuming equipment.
• Equipment Depreciation and Maintenance: Procurement and depreciation of the air compressor, lubricant replacement, consumable filter elements, and routine maintenance costs.
• Pressure drop loss: Pressure losses caused by improper pipeline design force the air compressor to operate at higher pressures, thereby increasing additional energy consumption.

By establishing a comprehensive cost‑estimation model that accounts for both direct electricity costs and hidden losses, enterprises can more accurately assess the true operating costs of pneumatic equipment and obtain reliable data to inform subsequent energy‑saving upgrades and pipeline network optimization.