How much does 1m³ of compressed air cost?

Introduction

The costs for compressed air are an important factor for many companies. Compressed air is used in numerous industrial processes and can make up a significant portion of operating expenses. In this article, we explain how the costs for 1m³ of compressed air are composed and what factors influence them. We also show how companies can optimize their compressed air costs to save money and improve efficiency.

Basics of Compressed Air Costs

To understand the costs for 1m³ of compressed air, we must first know the basics. The costs consist of several components:

• Energy costs: The largest cost block. They are incurred by the power consumption of the compressor.
• Acquisition costs: Costs for the purchase and installation of the compressed air system.
• Maintenance costs: Regular maintenance and repairs to maintain the system’s efficiency.

Energy costs make up the largest portion, often up to 75% of the total costs. Another important point is the compressor’s specific performance. This indicates how much energy is needed to generate a certain amount of compressed air. The specific performance is measured in kWh/m³ and can be determined through regular measurements.

Energy Consumption and Electricity Costs

The energy consumption of a compressed air system depends on the performance of the compressor and its operating time. A more powerful compressor consumes more electricity but can also produce more compressed air in less time. Therefore, electricity costs are a crucial factor in calculating the costs for 1m³ of compressed air.

To calculate electricity costs, we use the following formula:

Electricity price (€/kWh) · specific performance (kWh/m³)

For example: Suppose the electricity price is 0.20 €/kWh, and the compressor’s specific performance is 0.126 kWh/m³. Then the energy costs for 1m³ of compressed air are:

0.20 €/kWh · 0.126 kWh/m³ = 0.0252 €/m³

The specific performance can be determined through regular measurements. These measurements should last at least four weeks to obtain accurate results. Here’s an example of the specific performance of two compressors:

• Compressor 1: 17,472 kWh / 145,600 m³ = 0.12 kWh/m³
• Compressor 2: 4,368 kWh / 27,300 m³ = 0.16 kWh/m³

The total costs for the generated compressed air can be calculated by summing up the energy costs of both compressors. These calculations help companies monitor and optimize the efficiency of their compressed air systems.

Cost per Cubic Meter of Compressed Air

The cost per cubic meter of compressed air depends on various factors. In addition to energy costs, acquisition and maintenance costs also play a role. To calculate the total cost for 1m³ of compressed air, all these factors must be considered.

An example of calculating the cost per cubic meter of compressed air for an oil-injected screw compressor:

• Energy costs: 0.0252 €/m³ (as calculated previously)
• Acquisition costs: 10-15% of total costs
• Maintenance costs: 10-15% of total costs

The average energy costs for 1m³ of compressed air range between 3 and 5.4 cents. These costs can vary depending on electricity prices and the compressor’s specific performance. Acquisition and maintenance costs also significantly influence the total costs.

An example calculation for the total cost per cubic meter of compressed air could look like this:

Total cost = Energy costs + (Acquisition costs · Share) + (Maintenance costs · Share)

Assuming acquisition and maintenance costs each account for 12% of the total costs, the calculation would be as follows:

Total cost = 0.0252 €/m³ + (0.0252 €/m³ · 0.12) + (0.0252 €/m³ · 0.12) = 0.0315 €/m³

This calculation shows that the total cost for 1m³ of compressed air can be around 3.15 cents. These costs may vary depending on specific conditions and the efficiency of the compressed air system.

Factors Affecting Costs

The costs for 1m³ of compressed air are influenced by several factors. These factors can significantly affect the total costs. Here are the main influencing factors:

• Electricity price: The price per kilowatt-hour (kWh) has a direct impact on energy costs. A higher electricity price increases the cost of generating compressed air.
• Compressor performance: The specific performance of the compressor (kWh/m³) determines how much energy is needed to produce a certain amount of compressed air. More efficient compressors have lower specific performances.
• Operating pressure: A higher operating pressure requires more energy, which increases costs. The optimal operating pressure should therefore be chosen carefully.
• Leaks: Leaks in the compressed air system lead to energy losses. A leak of just 1 square millimeter at 6 bar can cause costs of up to 650 € per year.
• Maintenance: Regular maintenance and upkeep of the compressed air system are essential to maintain efficiency and avoid unexpected failures.
• Heat recovery: Using the waste heat from the compressor can reduce total costs by utilizing the heat for other processes in the company.

In addition to these factors, acquisition and maintenance costs also play a role. Therefore, companies should consider all these influencing factors to optimize the total costs of their compressed air systems.

Optimization of Compressed Air Costs

Optimizing compressed air costs is of great importance for many companies. Through targeted measures, operating costs can be reduced, and efficiency can be increased. Here are some proven strategies for cost reduction:

• Regular maintenance: Regular maintenance of the compressed air system prevents energy losses and extends the lifespan of the equipment. Maintenance work should therefore be carried out on schedule.
• Leak management: Leaks in the compressed air system cause significant costs. Regular inspection and repair of leaks can help reduce these costs.
• Efficient compressors: The use of energy-efficient compressors reduces energy consumption. Modern compressors often have better specific performance and are therefore more cost-effective to operate.
• Heat recovery: The waste heat from the compressor can be used for other processes within the company. This lowers total costs and increases energy efficiency.
• Optimization of operating pressure: Excessive operating pressure increases energy consumption. Therefore, the operating pressure should be reduced to the necessary minimum.
• Monitoring and analysis: Continuous monitoring and analysis of compressed air systems help identify inefficient areas and take targeted optimization measures.

An example of an effective monitoring system is the AnalyzAir® from WRS Energie. This system analyzes compressed air-specific measurement data using artificial intelligence and provides recommendations for reducing energy costs. The AnalyzAir® can be easily integrated with any energy management system (EnMS) or compressor control system.

By implementing these measures, companies can significantly reduce their compressed air costs while improving the efficiency of their systems.

Leaks and Their Impact

Leaks in compressed air systems are a common problem and can cause significant costs. Even small leaks lead to a continuous loss of compressed air, increasing energy consumption and decreasing system efficiency.

The impacts of leaks are diverse:

• Increased energy consumption: To compensate for pressure loss due to leaks, the compressor must run more frequently and for longer periods. This leads to higher electricity consumption and rising energy costs.
• Reduced system performance: Leaks reduce the available pressure in the system, which can impair the performance of connected equipment and machinery.
• Higher maintenance costs: Due to the increased operation of the compressor, wear and tear increases, leading to more frequent maintenance and repairs.

Therefore, companies should regularly inspect their compressed air systems for leaks and repair them promptly. A proactive approach to leak management can significantly reduce operating costs and improve system efficiency.

Conclusion

The costs for 1m³ of compressed air depend on various factors, including energy consumption, acquisition costs, and maintenance expenses. By understanding these factors and taking targeted optimization measures, companies can reduce their operating costs and improve the efficiency of their compressed air systems.

Regular maintenance, leak management, the use of efficient compressors, and heat recovery are just a few strategies for optimizing compressed air costs. Companies that monitor and analyze their compressed air systems can identify inefficiencies and take proactive measures to reduce costs.