Is more kilowatts and more air better?
Like so many industries, the compressed air industry is in full swing. Not least driven by efficiency improvements with regard to energy consumption and therefore indirectly also with climate change.
If you are going to buy a new compressor, you will of course pay attention to that. In the past, it was often about more air to keep space when there was a higher consumption. That’s really different now. But is the climate all that matters?
No, it is a combination of a number of factors. Here I mention some important ones.
#1 The most compressed air at the lowest cost. The initial purchase is only part of that. What is the cost of electricity to run the compressor in the early years? What about the costs after five years? Since electricity accounts for 80% of a compressor’s total lifetime cost, properly mapping the total cost of ownership (TOC) is part of the essential preparation.
#2 Forget the idea that kilowatts are the most important factor in determining compressor size. A better question would be: How many m³/min does your factory really need? A miscalculation here can cost you many thousands of euros if you choose one that is too big for its job. Providing insight is a science in itself. If your production hasn’t changed much, it’s a good idea to match your replacement compressor with your old one. If it doesn’t or if you are not sure, always have an audit carried out by an independent expert.
#3 Have you made an analysis and do you think you are OK with it? Or have some manufacturers already made an offer based on their knowledge and skills? Have this checked by an independent expert. It usually doesn’t cost much and you immediately get an insight into what it really is all about. Do not forget to also include compressed air drying and filtering.
#4 Be aware of what pressure does to your energy consumption. One bar more pressure costs you in the long term a lot of money. With energy prices nowadays and in the future it will have even more impact on your cost. If you are using different pressures in your production facility it would be worth to look at separating the systems instead of reducing the pressure at local user points. All depending on factors of course.
#5 Make sure you system leaks are detected and closed. This can easily save you between 5% (good systems) and 25% (bad systems) of air consumption. It has a direct impact on the size of the compressor and thus the energy consumption.
#6 Look at where you are going to install the new compressor. An old compressor room might acceptable but be critical on for example the ambient air temperature in the old compressor room. Avoid high air temperatures because it rises the energy consumption of your compressor.
(see blog: https://www.oilfree-air.eu/avoid-high-ambient-air-temperatures-and-save-money/ )
#7 Be critical to what others say and don’t be fooled by the opinion of a reseller / dealer or manufacturer. For example VSD is not always the best solution, luckily often it is, but stay critical
(see blog: https://www.oilfree-air.eu/downside-of-using-large-vsd-oil-free-screw-compressor/ )
#8 Sometimes it is worth to install a spare connection in your compressed air system while you are making other investments at the same time. In case of future failure it becomes far easier to connect a temporary air solution and will save you downtime in this event. (electric , water and air)
#9 Look at the combination of compressors and dryers. What is the amount of water allowed in your system (Pressure dew point)? Can you use a refrigerant dryer instead of a more expensive desiccant dryer? And in case you do need a desiccant dryer would you choose for a heatless, blower heated or heat of compression (HOC) dryer ? (see blog: https://www.oilfree-air.eu/pressure-dew-point-pdp-explained-in-compressed-air-systems/ )
Conclusion: There are a number of other factors that influence your energy and investment cost. Before you switch to a capital purchase, let yourself be informed.
Please do not hesitate to contact us.