Managing Compressed Air Costs: A Comprehensive Guide for Manufacturers

When choosing an air compressor, many manufacturers fall into the trap of reviewing the upfront capital cost while neglecting total ownership expenses. In an era where energy consumption and maintenance expenditure can rapidly inflate overall costs, it’s imperative to grasp the factors contributing to these outlays within your manufacturing facility. As planning for 2024 will be starting shortly, let’s review what is included with compressed air expenses and potential avenues for driving cost efficiencies.

Energy Costs: The Backbone of Expenses

A surprising finding reported by Energy Star indicates that 76% of compressor ownership costs are channeled into electricity consumption. Amidst ongoing energy price increases, it’s crucial to focus your facility’s goal on delivering necessary air output efficiently and with minimal energy consumption. First, it is essential to understand the metrics that drive compressed air energy costs.

Calculating Compressed Air Energy Costs

• Rated Power: Start by tracking the rated power of your compressor system. 
• Motor Efficiency: Delve into the motor efficiency, the proportion of electrical input channeled into powering the air compressor. 
• Service Factor: Understand the service factor, a rating delineating the operational range a motor can accommodate beyond its rated horsepower. 
• Running Hours: Gauge the annual operating time of your unit, often organized around labor shifts. 
• Energy Rate: Obtain the energy rate from your local power supplier, a critical variable for cost analysis. 

Rated Power & Motor Efficiency

Efficiency ratings encapsulate the percentage of input power a motor expends to fuel the air compressor. Typically, the rule of thumb holds that older and smaller compressor motors tend to exhibit lower efficiency. A case in point is that a 100 HP premium efficiency motor typically has a motor efficiency rating of around 96%. Review your motor manufacturer’s datasheet to find this efficiency rating.

Service Factor

The service factor serves as a crucial indicator of a motor’s resilience. It determines how much a motor can operate beyond its rated horsepower without incurring damage. For instance, a service factor of 1.15 grants a 15% leeway over the rated horsepower, and avoiding continuous operation in the service factor zone is pivotal to preventing potential harm. It’s worth noting that some manufacturers promote full-load capacities that only partially utilize the service factor, warranting vigilant evaluation when assessing compressor capabilities.

Running Hours

Your unit’s operational hours represent its duration at a specific power level, typically measured annually. This evaluation is often organized according to work shifts, as air demand fluctuates between them. Machines running non-stop usually total around 8,000 hours per year.

Energy Rate

You can acquire the energy rate specific to your region through your local power provider. As a point of comparison, the average cost per kW-hour is approximately 0.23 cents in the USA and 0.40 cents (USD) in Germany.

Maintenance Costs: Supporting Efficiency

Even the most dependable machinery requires maintenance to preserve efficiency levels. Varied across compressor technologies, maintenance expenditures include consumables, condensate removal, and potential airend replacement.

Consumables

Consumable products include parts that require periodic replacement, including filters, separators, and oil. Replacement frequency varies based on the compressor type. In non-oil-free compressors, the downstream filter replacement expenses warrant particular attention due to their cumulative effect on pressure and energy consumption. Additionally, oil-flooded machines mandate oil changes every 6-12 months, whereas oil-free counterparts can operate on minimal oil for 2-3 years. Full synthetic oil is ideal for operators looking to extend the time between changes and offers less downtime and maintenance costs.

Condensate Removal

While comparing oil-flooded and oil-free compressors, it’s important to note their condensate production. Oil-flooded units generate a mixture of water and oil in their condensate, necessitating appropriate disposal procedures or implementing a filtration system to effectively separate the oil and water components. Making the correct choice between these options is crucial, as inadequate condensate management could lead to potential annual costs of up to $50,000. When deciding on a compressor, factoring in proper condensate disposal strategies is essential.

Airend Replacement

Replacing the airend is often an ideal solution to improve performance as compressors age. The longevity of airends varies across technologies, with replacement cycles ranging from 3-5 years to an impressive 20 years of continuous operation. Since replacement expenses can reach up to 70% of the original equipment price, securing professional guidance and conducting thorough assessments becomes indispensable.

Transforming Data into Savings

Although gathering and monitoring these metrics might initially appear intimidating, the annual savings in compressed air costs—amounting to thousands of dollars—can make the initial effort highly rewarding. Demonstrating these savings to your management justifies the initial work and contributes to a healthy bottom line at your company.

Discover More Insights

For a deeper understanding of the hidden costs of air compressor operation, we invite you to explore our comprehensive white paper titled "The Hidden Costs of Air Compressor Operation." Gain invaluable insights into how tracking and optimization led one company to save $125,000 annually and uncover actionable strategies for enhancing your bottom line through effective compressed air management.