Powering anything with compressed air is an expensive exercise because the physical compression process is so inefficient. When it comes to the mechanical output to end use devices, it typically costs about 10 times more to power with compressed air than it does to do similar things with direct drive electrical, once losses are considered.
But sometimes we find that compressed air must be used. Here are 5 ways to maximize your return from your compressed air power:
Load the compressor. The best efficiency with typical screw type compressors occurs when the compressor is loaded near its full load capacity. So, if you have a choice between multiple sizes, ensure you use the smallest compressor possible, loaded to its highest possible percentage. Typically, to achieve this some sort of thing with multiple compressors an external compressor controller is required.
Lower the pressure. Sometimes the compressor pressure is set higher then needed, well, just because it can be, and often nobody knows why. Realize that for the same number of cubic feet per minute output an air compressor consumes about 5% more for every 10 psi in higher pressure. In addition to this, the higher pressure causes more flow in unregulated devices (and leakage) downstream, about 1% more for every psi in increased pressure. Use of better compressor control makes the reduction in pressure less risky and easier to implement.
Reduce waste. There is nothing more frustrating to see a product that was made with significant care and expense immediately thrown into the trash by the user. If you think about it, that’s what is happening when compressed air is wasted by leakage or drainage: it and the energy required to make it is gone before it even gets to the end user. It is very inexpensive to find and repair most leaks, which often consume more than 30% of the total flow output of the compressors. Improvement requires that you and your staff make a conscious effort to improve. This usually involves adding regular leakage repair to your preventative maintenance program.
Lower the temperature. Excessively high temperatures and a dusty environment within the compressor room reduces the efficiency and the lifespan of your air compressors and dryers, costing you money. Ensure that the compressors are operating in a cool, clean environment and that any compressor heat is ducted out of the room, preferably used to displace building heat in colder months.
Buy efficient from the start. One of the best ways to ensure that your compressor runs efficiently is to purchase efficient equipment from the start. It may be time to replace your compressor due to age. When you do, check out the compressor Compressed Air and Gas Institute (CAGI) ratings published by most reputable compressor suppliers in North America before you buy, and choose wisely based on future cost. Choose a compressor or air dryer that has good efficiency numbers, and if the equipment will be running at partial loads, consider units with good power turndown capabilities like variable speed and variable displacement types.
About the Author: Ron Marshall
