Management guru Peter Drucker famously said, “You can’t manage what you don’t measure.” That’s true for nearly everything—including your compressed air system. Data logging can help you measure—and manage—compressed air system performance. By understanding how and when your compressed air system is using energy, you can discover opportunities for energy savings and optimization.
What is Data Logging for Compressed Air Systems?
What is data logging? Very simply, it is the practice of measuring system performance by attaching meters, gauges, or sensors to a system for an extended time while it is in operation. Unlike spot checks, such as a single meter read or pressure gauge read, data logging allows us to see how the system responds to real-time events and conditions over time. This enables us to find trends and correlate system performance to possible causes and drivers.
For a compressed air system, data loggers can be used to measure many aspects of system performance, including:
- Pressure
- Temperature
- Moisture Dew Point
- Flow
- Amperage
- Voltage
Typically, a data logging device—such as a pressure gauge or amp meter—is attached to the system for one to two weeks. This is enough time to gather information across several shifts and start to look for trends in the data. The data logger may query the system and record a measurement as often as every few seconds to measure system performance moment by moment. The data is then fed into software that can turn it into charts showing how the system behaves over time.
Data logging gives engineers visibility into different aspects of system performance to answer critical questions such as: How efficient is your compressed air system? Where are the biggest opportunities for energy savings and improvements? How do different production scenarios impact the performance of your air compressor? What is the carbon footprint of your system?
What Can Amp Meter Data Logging Tell Us About Compressed Air System Performance?
Fluid-Aire Dynamics uses a very simple method of data logging for compressed air systems: the amp meter. This involves attaching an amp meter to system controls for the air compressor. The meter records amperage every five seconds.
Analysis of compressed air system amperage over a 6-day period.
Simply looking at amperage can tell us a lot about air compressor performance. The amp meter tells us whether the compressor is off or on (loaded or unloaded) and how much energy it is using. Looking at this over time, and correlating system performance to events such as shift start/end and break times, can allow us to answer important questions such as:
- What is the average duty cycle of the compressor (how often does it cycle on and off)?
- How much time does it spend loaded (making compressed air) vs. unloaded (idle)?
- When does peak usage occur over the course of a shift, day or week?
- At what times is the system mostly idle?
- How much variability is there in compressed air consumption over a shift, day, or week?
- How much energy is consumed during periods of peak usage?
- How much energy is consumed during periods of minimum usage?
Looking at these questions will allow us to derive answers to more complex questions, such as:
- What are the energy costs associated with producing compressed air for the facility?
- How much air is being wasted?
- Are there times when the compressor is making more air than my production processes can use?
- Is the compressor appropriately calibrated for my compressed air needs?
- Is the compressor at risk of damage due to short-cycling (caused by under-utilization) or excessive drawdown (a sign that it cannot keep up with demand)?
- Do usage patterns during periods of no demand (e.g., when production processes are stopped) suggest significant leakage in the compressed air system?
- What is the carbon footprint for the system?
Aire Tip: Amperage data logging is sufficient for compressed air system optimization for the vast majority of users.
When Do You Need a Full Engineering Audit for Your Compressed Air System?
We find that 99% of the time, simple amperage data logging provides manufacturers with the information they need to make system improvements. This method of data logging is cheap, easy and non-invasive—it simply involves clamping the amp meter onto the compressor controls in the control room. The system does not have to be shut down at any time. Fluid-Aire Dynamics performs this service for free.
In some cases, it may make sense to perform a complete compressed air system audit. Engineering firms typically charge $10k or more for a full system audit—or much more for very large, complex compressed air systems. During this evaluation, they will install multiple types of data loggers at different points in the system. In addition to amperage, they will typically log pressure measurements at various locations throughout the facility. This is a much more time-consuming and invasive process; parts of the system may need to be shut down temporarily to install some kinds of data logging equipment.
A full study will provide more information that may be helpful in situations where additional diagnostics are needed. For example, if you are trying to diagnose a pressure drop problem in a large, complex system, having pressure data at multiple points in your compressed air system may be helpful.
However, simple amperage data logging is always a good place to start. The information from this exercise may turn out to be all you need. It may also provide important clues that will enable you to perform more targeted additional investigations.
Aire Tip: A full engineering audit may provide more detailed information for the diagnosis of complex compressed air system problems.
How to Use Data Logging for Compressed Air System Optimization
Information from data logging is used to discover trends in system performance and find opportunities for system optimization. These might include:
- Is there an opportunity to reduce overall plant pressure without reducing production capacity? Read: Reduce Plant Pressure to Save Money and Energy.
- Do I need a larger compressor, or a secondary backup compressor, to keep up with periods of peak demand?
- Is it worth investing in a smaller backup compressor to use during periods of lower demand?
- Would a variable speed drive (VSD) compressor save energy and money for my facility? Read: Why Choose or Upgrade to a Variable Speed Drive Compressor?
- Do I need a sequencer to control multiple compressors?
For example, one customer that we worked with ran a 100 HP compressor to support their production for only one shift, but kept the air compressor in operation during the evening hours to maintain some systems (including HVAC and fire sprinklers). Based on the data logging exercise, we determined that it made sense to install a very small 5 HP compressor to run those systems. The energy saved by powering down the main compressor when not in use for production more than paid for the cost of the smaller compressor within the first year.
Knowledge Is Power: Improving Air Compressor Performance
When it comes to compressed air system performance, knowledge is power. The more you know about how your system is behaving and how trends are changing over time, the better you can optimize your system.
Fluid-Aire Dynamics performs amperage data logging for free as a service to our valued customers and industry friends. If you would like to schedule data logging for your compressed air system, give us a call. Our compressed air system engineers can run the study, help you interpret the results, and suggest improvements that will improve system performance, maximize the life of your system and reduce your energy bills.
Contact us to schedule compressed air system data logging.
