Compressed air is a form of stored energy that is used to operate machinery, equipment or industrial processes. Compressed air is used in most manufacturing industries and in some service industries, especially in cases where direct use of electricity to power tools or devices is impractical or even dangerous. A typical electrically driven air compressor compresses about 7 volumes of air at atmospheric pressure into 1 volume of higher pressure air. The high pressure air thus obtained is distributed to devices or tools in which it expands to atmospheric pressure, thus releasing the energy necessary for their operation.

During the process of compression, and subsequent cooling of air to ambient temperatures, heat and humidity are released. Depending on the type of application, it may be necessary to control the excess humidity in the compressed air due to possible problems with the piping (corrosion) and the equipment used.

Compressed air costs

This section will help you better understand what it costs to produce and use compressed air.

During the first ten years of life of a conventional air-cooled compressor, running for two shifts, the operating cost (electricity and maintenance) will represent approximately 88% of the total cost of lifetime. The initial cost of equipment fluidairedynamics and installation by fluid-aire dynamics, will represent the remaining 12%.

Since energy accounts for approximately 76% of the overall operating cost over the lifetime, it is critical to design and purchase the most efficient components for your compressed air system. It is recommended that purchasing decisions be made with the operating costs in mind for the overall expected life span and not just the initial cost of the hardware.

Some industrial compressors are water cooled. In these cases, the additional costs associated with water and its discharge, the operating costs of the water cooling system, and the costs of pumping and chemical treatment should be assessed. The Figure 4 is a simplified table provides information on electricity costs of operations on one, two or three shifts in a typical industrial facility. The table shows these costs for air compressors with an output of 10, 15, 25, 50 and 100 HP. It is assumed that the average compressor load is 65% of the rated load.