As counter-intuitive as this may be, it can be true.
For example, if you use a horse drawn carriage to take you from Chicago to New York you will save a tremendous amount of energy – virtually no gasoline, and most likely a big contribution to the cleaner air. However, it will take many days longer to arrive, added cost of hotels and meals (which takes up energy for the stay, the preparation of food, etc.) and the “downtime” of not being at your destination earlier. As silly as this example may first appear, it is actually quite sound! When focused only on “energy cost” one can fail to appreciate the benefit the extra energy adds to productivity and output.
70% of usable compressed air (after leaks which is an entirely separate issue) is still used for blow off applications simply because more energy efficient blowers just cannot do the job. What is the point of saving energy if you slow down production?
Other factors that are important in energy reduction is the impact the reduction has in:
Factory Output: There have actually been cases where blowers have replaced compressed air blow off and then, the compressed air put back because the blowers lacked the energy to perform the job and output decreased. More often, blowers have been put in and then compressed air blow off “added in” after for the same reason. Both system would be running when the compressed air blow off would normally be enough to be effective. So now you have a blower system AND compressed air blow off. The energy use is either the same or maybe even higher! Generally factories want to increase output, not reduce it. The increased output utilizing compressed air should be considered as it can more than offset perceived energy savings.
Maintenance Cost Issues: Ever wonder why air tools are so popular over electric tools? One factor is maintenance cost. Compressed air operated devices are simpler, more rugged and last longer and subject to much less maintenance than most other options. One example is vortex tube technology used for spot cooling and especially for cabinet enclosure cooling and cooling industrial camera enclosures. We are certainly not saying that vortex tube cooling for cabinet enclosures apply everywhere but, in a very dirty and/or humid environment the increased energy use using compressed air can, and are, in those situations easily offset in high maintenance cost of just the time and material cost of replacing filters, not to mention replacement cost of air conditioning equipment in those kinds of environments. In very dirty environments vortex tube operated air conditioners also keep out dirty air, and keep internal components “clean” extending controls lifetimes and replacing costly controls.
Capital Costs: Compressed air operated equipment is simpler and typically much lower cost – period. And they last longer too. Capital costs of any equipment amortized over a reasonable period of time need to be considered against energy costs.
Space: The footprint of the equipment doing the job of blow off, drying, cooling, or moving is important. It is important in the opportunity cost in utilizing the space, and for worker accessibility. Compressed air operated equipment is smaller, lighter, compact and rugged.
Personnel Cost: Labor is becoming more costly as time goes on. A potential qualified labor shortage is looming (despite the rise of machines). So anything that will save on labor is a factory cost saving. Compressed air nozzles, air knives, air operated conveyors, vortex tube technology is all essentially maintenance free. When considering the cost of alternative energy, consider the added labor cost as a major factor, not only for the time taken up by the person, but the cost of other things related to production “not” being done.
I am sure many people, especially those touting blowers as the ultimate solution to compressed air will disagree but I am certainly willing to meet and discuss further. I will bring my car and they can bring their energy saving horse and buggy – but please, do not keep me waiting!
Nex Flow manufacturers quality, and economical, specialized compressed air solutions for blow, off, cooling, drying, and moving with representatives worldwide. www.nexflow.com