While variable speed drive (VSD) machines are generally the best energy saving compressor option, technological innovations make fixed speed models a viable second choice. Usually, the reason operators choose fixed speed over VSD compressors is due to initial investment cost.
As a comparison, fixed speed compressors with state-of-the-art tools, like the ES4000 connect with ICONS, can save up to 30% on energy costs. With advanced VSD models, operators can expect to save a minimum of 45%. Of course, real numbers are based on actual usage and conditions.
This article outlines how to achieve savings with both types of air compressors to help you determine the right solution. Read on to learn more about which one is best.
Technologically-driven fixed speed features
Since fixed speed compressors are built to run at a constant speed, opportunities for savings are added through technology. This means that if you're running one of these machines without advanced controls and technology, energy reduction is limited. If you work in a small-medium size industry and don't need fluctuating air pressure, you can benefit from the following features.
Delayed second stop
You may be aware of how a car stops and starts at an intersection to save gas consumption. This same principle can be applied to air compressors with delayed second stop (DSS). With fixed speed machines, DSS runs the compressor only when needed. You'll find this available on controls, like the ES4000 connect, designed to optimize performance.
Air leak detection
As leaks can cause 20% of air to escape if not properly checked, this translates into lost revenue. For example, a leak of 3/8 inch operating at 100 psig translates to 32,500 EUR per year. While it's possible to check any machine for leaks with pressure gauges and using the soap test, the ES4000 connect identifies leaks automatically. This means you'll get alerted instantly on potential problems, minimizing such losses.
Remote monitoring and control
Collecting information on more than 30 data points, the ES4000 connect can send insights directly to your phone with ICONS. This ease of access to useful data is what makes fixed speed compressors worth a second look. However, as you'll see below, VSD machines still remain the best in overall performance.
VSD energy saving compressor benefits & technology
The main reason why VSD compressors are more efficient than fixed speed machines is due to how they're designed. These machines contain inverter technology that allows motors to change speed depending on air demand. This means a single VSD machine can work across multiple applications with different or fluctuating airflows and requiring different pressure levels.
In fact, in most cases, VSD equipment is at the cutting edge of sustainability requirements. Due to their adaptable operations, there's much room for innovation and future proofing. This is made possible with features like frequency inverter regulation (IVR) and built-in energy recovery.
Since 80 to 90% of energy used by an air compressor is converted to heat, it's important to recover as much as possible. This heat is valuable for other areas of your facility. While external energy recovery is available for most compressors, built-in systems enhance performance.
Monitoring and controls
Also, with VSD machines, you tap into advanced monitoring and controls, like with the ES4000T, ECOntrol6i, and ICONS. The ES4000T controller monitors compressor performance, while ECOntrol6i synchronizes multiple machines and ICONS provides remote updates on system status.
General tips on increasing efficiency
Whether you're operating a fixed speed or VSD air compressor, there's things you can do to cut costs. This includes checking for leaks, as mentioned above, as well as utilizing energy recovery systems, and regular changing filters.
While you can invest in the most advanced energy saving compressor model, it's still important to perform regular maintenance. This is where advanced monitoring and control tools come in handy. They're meant to make it easier to pinpoint and alert you to problem areas, so you can maximize uptime and save money.
Additionally, it's worth monitoring ambient temperature where your air compressor is placed. Since these machines generate a lot of heat, it's worth keeping the environment as cool as possible. With each reduction of 5°C, you can achieve energy savings of 1.5%.
Choosing the right compressor
If you're deciding between fixed speed and VSD machines, it's important to consider the amount of pressure and flow you need to complete a job. Not only does the type of engine matter, but also the size of the machine.
If you invest in equipment that's too big, you'll produce more air than necessary. Too small equipment results in an overworked machine. These conditions impact load and unload conditions of fixed speed units. This is where VSD compressors have an advantage, as they adapt speed based on application. Variable speed drive machines are especially useful for food and beverage and medical industries.
Generally, compressors operating at 50% capacity consume 20% more power than one reaching its designed limitations. If you need further information on what makes the most sense for you, feel free to reach out. Our team is happy to help.
