Choosing the right air compressor

There are many things to consider when selecting the next air compressor. Making an informed decision when selecting your new air compressor can have an impact on your operation, both financially and operational.

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A Professional Guide to Upgrading Your Air Compressor

Traditionally, air compressors were something of a forgotten and neglected beast. As important as they are, the factory’s air compression would just sit in the corner of the factory or workshop chugging away, day after day, with very little attention paid to it. The occasional service aside, compressors were largely ignored.

air compressor from Atlas Copco

Atlas Copco Air Compressor

However, that was then. Today, manufacturers can’t afford to be so negligent with any of the equipment in their space. A poorly-chosen air compressor could indeed cost the manufacturer thousands of dollars in wasted energy costs per year.

How do you know if you’ve got the right air compressor?


Air compressors are not new technology; they’ve been around in one form or another for over 100 years now. There are however a greater variety in air compressors now, for a wider range of functions from industrial through to home use. It’s definitely a good idea to invest in a newer machine if your air compressor is starting to show its age.

The latest air compressors on the market are vastly more efficient, and can offer manufacturers considerable ongoing energy savings, but only when the correct air compressor for the application is chosen.

The key to selecting the right air compressor is to do a proper due diligence process and to audit your business. Understand what your business needs an air compressor for, and what tools will be used with it. That knowledge will help you to narrow down from the vast range of air compressors on the market which is the one best suited to your operation.

“When we carry out an air audit, we are looking at the variations in demand,” David Brown, Product Manager at Atlas Copco Australia, said. “We can then put the audit data into our unique software package and turn the fluctuations into an analysis of dollars, which ultimately gives the customer the information they need on the energy savings possible.”

Understanding the jargon


The biggest problem when shopping for air compressors is the sheer amount of jargon that will be thrown at you when you compare specifications. Air compressors aren’t particularly complex machines, but their effectiveness and efficiency are measured in ways that don’t apply to a lot of other machines.

When discussing which air compressor is right for you with your Atlas Copco representative, here are the key specifications you should be familiar with:

● CFM: CFM stands for cubic feet per minute, and is the basic measuring tool that tells you how fast a compressor can supply air. Basically, if a tool needs more air than the compressor can supply, there will be a lot of downtime in using the tool as it waits for the compressor to supply enough air to it. The more powerful the tool, the higher the CFM will need to be to operate it properly.
● PSI: For home handyman tools, pounds per square inch, or PSI, isn’t relevant. For industrial applications, however, it is important. A higher max PSI also allows for a smaller tank to hold more air and perform with the effectiveness of a larger tank.
● dB: Decibels, or dB, is the rating for the noise that a machine makes, and while you might dismiss this number as a comfort factor for those using it rather than a major consideration, it’s actually very important. Air compressors can be very loud, and with the way that decibels measurements work, an 80-dB machine is actually four times as loud as a 60-dB machine.

Finding energy savings



Specifically, in relation to air compressors for manufacturing, VSD (Variable Speed Drive) compressors are very popular machines. That being said, in the hunt for better efficiency and savings, VSD compressors are not the most efficient choice. “If a manufacturer has a constant, steady demand, a VSD compressor is not going to save them a lot of money,” Atlas Copco’s Brown said. “It is not always the case that VSD will save them money at all,” he added. “If we can’t get a payback period of a VSD compressor of less than two to three years, we don’t always promote that as being the right machine.”

This is why it’s important to discuss the specific environment and expected usage of the compressor with the supplier beforehand. That being said, Brown added that with fluctuating demand, it is possible to achieve a payback within 18 months to two years, though sometimes it can be less than 12 months.

“The key is to keep performing audits,” Brown said. “For our customers, after the compressor has been in regular use for a month, we will conduct another audit to determine what savings are there, and what can be achieved over the long term.

Generally speaking, a company will look to replace their air compressor only once the existing one is reaching the end of its life. As air compressors can last for many years, developments in the machinery can mean that the savings can be significant.

“For example, we conducted an air audit for a customer and were able to simply replace a 37kW compressor with a 37kW VSD compressor, saving the company 30 per cent on its energy costs.” With energy costs being by far the largest proportion of the overall cost of an air compressor, (the purchase price itself is only 10 per cent of the lifetime cost of the machine) these savings are significant. “The general consensus is that energy costs make up the bulk of the overall cost, around 75 percent, with ongoing maintenance making up the other 15 per cent,” Brown said

Why buy from Atlas Copco?


Atlas Copco is the largest manufacturer of air compressors in the world, and part of its success has been in its ability to supply the right air compressor for every application. Brown said that it is important to watch out for VSD compressors that use a standard drive motor and fitting an ‘off the shelf’ inverter drive package. This is not something that Atlas Copco does, but is present in some other manufacturer’s product line.

“The problem with this arrangement is that when the standard motor is running at low speed, there may be a cooling problem, because the cooling air flow is lower than its design flow. The correct arrangement is to use a motor designed for VSD control,” Brown said.

The latest examples of VSD, such as the new GA VSD+, utilises oil cooled, interior permanent magnet (IPM) motors, where the motor shaft and element shaft are one, eliminating all drive losses - meaning there are no gears, belts or shafts to maintain. These new GA VSD+ air compressors also offer a major leap forward in FAD (Free Air Delivery) with improvements of up to 12 percent, and are a breakthrough in energy-efficiency requiring on average 50 per cent less energy than a comparable idling compressor.

“The other benefit of these new machines is that they’re much quieter, down to just 62db(A),” Brown said.

To find out more about conducting an air audit of your facility and to get more information on Atlas Copco’s full range of air compressors, including the new GA VSD+ range, call Atlas Copco on 1800 023 469 .

Air compressors