Compressed air consumes a large amount of electricity in manufacturing/industrial facilities. Unfortunately, many compressed air systems operate with little to no maintenance/oversight, leaving air lines vulnerable to leaks and inefficiencies. Furthermore, compressed air is often used unnecessarily. These failures ultimately result in higher utility bills.
Low Cost/No Cost Approach
One of the cheapest ways to ensure your air compression system is in good shape is to detect leaks throughout the system. An example of how much a leak costs a facility is shown below:
In order to calculate the cfm leakage from out of an orifice, the following equation was used:
Using this equation, a 1/16” orifice with a gage pressure of 100 psig would leak 4.8 cfm of air (if the orifice is round that number should be multiplied by 0.97, and if the orifice is sharp that number should be multiplied by 0.61).
So … What does that leak mean in dollars? Based on an electricity rate of $0.08 per kWh and a plant that runs approximately 5 days a week with three shifts, the total cost of that one round leak is approximately $422 per year.
As shown by the cost of one 1/16” leak in an air compression system, a program to detect leaks on a regular basis would pay for itself rather quickly.
Another inexpensive method for keeping your compressed air system in good shape is ensuring the end-uses for the compressed air are actually useful. Because air is seen as an inexpensive commodity, there is a tendency for people to utilize compressed air for such things as cooling or cleaning an area even though it costs substantially less to use a fan or a broom. Using compressed air outside of its intended function is not cost-effective. Communicating to employees the overall costs of using compressed air for non-approved end uses should be a priority for plant facility managers.
Make Your Air Compressors Work for You: Capital Projects
Leaks sealed? Employee behavioral change effective? If these low cost/no cost measures have been implemented successfully, then there may be some cost-intensive measures that your plant can take to save energy.
Because more than 80 percent of the electrical energy going to a compressor becomes available heat, a heat recovery system could save a facility money by utilizing the heat produced in the compression system to heat another system.
Another possible cost-intensive measure is to install a control system to lower the compressor’s output when the plant’s demand is low.
The third more cost-intensive measure is to install a new air compression system in order for it to be the most efficient available.
Optimizing a compressed air system, be it through low cost/no cost measures or capital projects, will make your plant more energy efficient. Keep air compressors in mind during your facility evaluations. If you need help with that, contact us. Remember, inside your facility, air is definitely not free.
Written by: Kimberly ‘Captain’ Janeway