Information from Compressed Air Best Practices
The component-level approach is often taken to improve a compressed air system, and it typically involves very specific, short-payback, and easily quantifiable measures (i.e. replacing an old compressor with a more efficient one). The Department of Energy and the Compressed Air Challenge, however, advocate a systems approach as the best practice for analyzing and improving a compressed air system.
The Compressed Air Challenge is a voluntary collaboration of industrial users; manufacturers, distributors and their associations; consultants; state research and development agencies; energy efficiency organizations; and utilities. Below for your convenience are some of their recent publications.
Condensate drains are possibly the least glamorous and most ignored component of a compressed air system but nevertheless, a most important part. No matter how much you spend on that fancy new compressed air system, VFD’S pin-stripes and flashing lights notwithstanding, not spending a little effort with your drain choice could cause you no end of headaches and increased operating costs for years to come.
Compressed air is a source of energy in support of manufacturing. It is also a very high cost component in the production of the goods and services at a plant. As such, improving the efficiency of an existing system offers a large savings opportunity. To realize the potential, the system dynamics must be understood and the supply from the compressors must always match the real system demands.
What are the conditions inside your pipes, is it cloudy and hot with showers or cool and dry? Could there be snow and blowing snow and excessive icing conditions? Are there smog and dust storm conditions or is the air as fresh as a mountain breeze. All these conditions are commonly experienced inside compressed air systems
This fact sheet contains valuable information for businesses such as service stations, fleet maintenance facilities, and “quick lube” shops that generate and handle used oil. It summarizes the U.S. Environmental Protection Agency’s (EPA’s) used oil management standards—a set of “good housekeeping” requirements for used oil handlers. These requirements are detailed in Title 40 of the Code of Federal Regulations – Part 279.
Leaks can be a significant source of wasted energy in an industrial compressed air system, sometimes wasting 20-30% of a compressor’s output. A typical plant that has not been well maintained will likely have a leak rate equal to 20% of total compressed air production capacity.
To gain about one horsepower of mechanical energy from a compressed air powered motor it costs seven times as much at the input of the air compressor. And surprisingly between 20 and 30 percent of this valuable power is lost even before it gets to the end use. These facts are surprising to people because their compressor rooms are notoriously lacking in even the basic instrumentation.
Having a fundamental understanding of how your plant’s compressed air system works and what forces influence it will help you improve its performance. The overall efficiency of a compressed air system can be as low as 10–15%. The figure below shows two main components of inefficiency — one is from the wasted air due to losses through leaks, artificial demand and inappropriate uses, the other is due to heat of compression.
Understanding Pressure Drop
One of the many issues that can affect compressed air system efficiency and pressure stability is pressure drop. “The first and foremost complaint I normally hear from an operator or production area is, ‘I don’t have enough pressure’,” says Frank Moskowitz, one of CAC’s advanced management instructors.
Dealing with High Volume Intermittent Demands
In many industrial plants there are one or more applications with intermittent demands of relatively high volume. Dense phase systems can cause severe dynamic pressure fluctuations affecting quality of the end product in a plant. Usually, the correct sizing and location of a secondary air receiver close to the point of high intermittent demand can relieve this.
Analyzing Interval Data to Establish Compressed Air Flow
Energy management requires accurate and repeatable measurement of critical data, which is easily monitored and analyzed as required to stimulate required action. When a compressed air system assessment is implemented, the basic minimum measurement protocol to establish the baseline (pre-measurement) and qualify and quantify the results (post-measurement) is often flow by individual air compressor and the whole air system.