Electric Motors vs Pneumatics: Energy Consumption and Cost

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Electric Motors vs Pneumatics: Energy Consumption and Cost

Electric drives are increasingly replacing traditional pneumatic drives in various applications. This shift is driven by the inefficiency, service, maintenance, and high energy costs associated with pneumatic systems. Despite the lower initial purchase cost of pneumatic drives compared to electric motors, the ongoing energy and service costs are significantly higher, and their lifespan is considerably shorter.

This article will delve deeper into the reasons for replacing pneumatics with electric motors, especially focusing on energy costs, and will provide real-life examples with Millitec’s servo-driven machinery.

Advantages of Pneumatic Drives

There are definitely some advantages of pneumatic drives:

  • Low initial costs.
  • Ability to withstand high-temperature and heavy loads.
  • Capacity to maintain constant pressure.
  • Easy to operate.

Disadvantages of Pneumatic Drives

Energy Inefficient

However, the main drawback of pneumatic systems is their high electricity consumption and energy inefficiency. Chart A below shows that electricity costs make up 76% of the total operating expenses over the compressor’s service life, while installation and maintenance each account for just 12%. According to the U.S. Department of Energy’s “Energy Tips-Compressed Air” (August 2004), “Compressed air is one of the most expensive sources of energy in a plant. The overall efficiency of a typical compressed air system can be as low as 10 to 15%.” This means that compressors convert only a small portion of the input energy into useful power. This inefficiency results in high energy consumption and energy bills.

Pie Chart, Cost of Operating Compressor

Chart A: https://www.linearmotiontips.com/electric-actuators-vs-pneumatic-cylinders-total-cost-of-ownership/#

Maintenance and Performance Issues

Pie Chart, Air Supply for Production

Chart B: https://www.linearmotiontips.com/electric-actuators-vs-pneumatic-cylinders-total-cost-of-ownership/

Pneumatic systems’ performance can be significantly affected by factors such as air quality, wear and tear, and leaks. These issues require ongoing monitoring and maintenance to ensure optimal performance. For example, pneumatic systems experience some degree of leakage, with 30% of the air supply for production lost due to leaks (Chart B), resulting in higher costs. A single air leak with a diameter of 0.25 inches can cost approximately $9,000 annually (Chart C). Pneumatic systems rely on tight rod and piston seals to prevent leakage caused by wear and tear, but the maintenance process of constant monitoring and adjusting can be both time-consuming and expensive.

Chart C: https://www.techbriefs.com/component/content/article/35859-electric-actuators-offer-performance-efficiency-and-cost-benefits

In contrast, electric actuators maintain their efficiency over time with minimal upkeep. This performance stability reduces maintenance efforts and contributes to a more predictable and lower long-term operational cost.

Pneumatics vs Motors: Total Costs

While pneumatic drives have a lower initial purchase cost, it is essential to consider energy, maintenance, and other investment costs.

Bar Chart, VSD's Running Cost Comparison

The Chart illustrates Millitec’s Volumetric Servo Depositor’s (VSD) operating cost comparison between the two systems. The chart indicates that the Servo Depositor is significantly more cost-effective than the Pneumatic Depositor over time. The running costs for the Pneumatic Depositor rise sharply, reaching approximately 30,000 GBP over 24 months, while the Servo Depositor’s costs remain much lower, at around 5,000 GBP. Thus, the Servo Depositor presents a more economical option for long-term use.

In conclusion, this table shows that the electric actuator, despite its higher initial purchase cost, is much more cost-effective over three years due to lower operating and replacement costs.

A real-life example of the costs for a noodle-cutting application illustrates this point:

Table A: https://www.linearmotiontips.com/electric-actuators-vs-pneumatic-cylinders-total-cost-of-ownership/

Table A compares the costs of using a pneumatic cylinder versus an electric actuator over a three-year period for a specific application. Key points include:

  • Purchase Costs: The pneumatic cylinder costs about $400 for a one-month lifespan, while the electric actuator costs $1500 for a three-year lifespan.
  • Annual Electricity Costs: The pneumatic cylinder incurs $50.40 annually, whereas the electric actuator incurs only $8.10.
  • 3-Year Total Cost of Ownership (TCO): The pneumatic cylinder’s TCO is $4111, while the electric actuator’s TCO is $1524.

In conclusion, this table shows that the electric actuator, despite its higher initial purchase cost, is much more cost-effective over three years due to lower operating and replacement costs.

Millitec’s Approach

As a leading food machinery manufacturer, we strive to create machines that not only perform perfectly but are also energy efficient. That’s why our machines are pneumatic-free. Take Millitec’s Volumetric Servo Depositor as an example,

In summary, our depositor is designed to be servo-driven and can save you around £13,222 annually:

  • Annual Power Consumption: The servo system consumes significantly less energy (3459.456 kWh) compared to the pneumatic system (36514.93 kWh).
  • Annual Cost: The cost of running the servo system (£1,383.78) is much lower than the cost of running the pneumatic system (£14,605.97).

Conclusion

While pneumatic drives offer some advantages, such as lower initial costs, their high energy consumption and maintenance costs make them less cost-effective in the long run. Electric motors, though initially more expensive, prove to be much more efficient and cost-effective over time. As demonstrated by Millitec’s Volumetric Servo Depositor, switching to electric drives can result in significant energy savings and lower operational costs, making them a better investment for the future.

At Millitec, we are committed to providing high-performance, energy-efficient solutions for your machinery needs. If you have any questions or would like to learn more about our products and how they can benefit your operations, please contact us!

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