Gas Technology: Digital Age management
With tools such as digital loggers and wireless communications, systems operators can get an accurate picture of plant energy usage patterns.
Today’s industrial energy systems are complex and sophisticated. Necessarily, systems that monitor and optimize energy usage must also be complex and sophisticated. Too often, owners install new plant equipment or building comfort systems without consideration of how to monitor those systems’ operating efficiency.
Fortunately, with tools such as digital loggers and wireless communications, we can correct for these omissions and get an accurate picture of plant energy usage patterns. It’s not enough to look at monthly bills for natural gas, electricity or steam to determine if you can save energy. You need to look at where it is being used, with the ability to evaluate hourly and daily usage patterns.
Help Getting Started
The steps to gathering complete energy information can be complex, and it takes commitment to really make energy management work. Aaron Mason from Hawkeye Energy Solutions was a presenter at a Technology Marketing & Assessment Forum (TMAF) sponsored by the Energy Solutions Center. His firm has wide experience helping industrial firms get a grip on their energy usage.
Need Management Involvement
Mason points out that it is essential to get a buy-in from corporate management. He says, “A lot of energy management systems get installed with the best intentions but end up collecting dust and providing no value. Usually this happens because the goal of saving energy doesn’t have a lot of support from upper management.”
Management needs to understand that dollars spent on installing equipment to collect and tabulate energy data can provide a quick payback, and will continue to provide savings as long as the system is supported and used. The payback is sometimes very short, and it’s the right thing to do for other reasons as well. Energy usage information can improve manufacturing processes, sharpen product pricing, and reduce facility emissions and its carbon footprint.
Get Expert Help
Unless your company has an experienced energy management staff, you will want to look for help from an energy consultant. Find one that has specific experience in your industry, and is qualified to make recommendations on selecting energy data collection and analysis tools. Mason notes that firms such as his can install and manage these systems for industrial customers. “We try to get involved early in the process and we work to get a solid understanding of what the industrial customer needs. Some need very simple, low-cost systems with robust data collection. Others need higher-end systems that interface with existing automation systems and provide real-time analytics.”
Energy monitoring experts indicate that nearly always, the process will involve adding additional sub-metering equipment, and data terminals to receive the information. Mason says, “It’s just like asking how to trim a budget without bank statements to see where you are spending money. It starts with metering.”
Get the Low-Hanging Fruit
Your consultant will help you to identify the major energy intensive industrial processes or building comfort systems at your facilities. Obviously these are good places to start installing sub-metering, or perhaps collecting data from existing but unused data outputs. Examples might be steam or hot water boilers used for comfort or process applications, heat treating systems, large motors, engine or turbine generators, large air compressors, chillers, furnaces or ovens. In many cases, this equipment already provides a data output with information on energy usage. You may be able to identify, capture and include this output data into your complete plant energy budget for analysis.
These large units usually account for a major proportion of plant energy usage. A consultant can give guidance on selecting one of several standard communications protocol to transmit data to a central data logging and processing point.
Understanding Fixed and Variable Energy Usage
In a publication titled “Improving Process Heating Performance”, the Industrial Technologies program of the U.S. DOE points out how remote sensing and energy data management can especially benefit process heating applications. These systems have both fixed and variable losses. Variable losses depend on the amount of material being heated, while fixed losses do not.
Fixed losses are incurred as long as the unit is being used regardless of the capacity at which it is operating. The report notes, “In many cases, fixed losses can be minimized by improving process scheduling, such as reducing the amount of time that systems operate far below rated capacity, and minimizing idle time between batches.” Collecting data on energy usage patterns is essential to these improvements.
Timing Can Be Critical
For industrial energy users, the time of energy use can be just as critical as the total units of energy used. Electric, gas and steam suppliers often have significant demand charges or time-of-use penalties. By avoiding peak demand times, or by smoothing out the 24-hour energy usage cycle, utility bills can often be dramatically reduced. For this reason it is important to collect dinformation on instantaneous and hourly usage patterns.
Some energy suppliers also offer very attractive interruptible rates if you can discontinue using energy or dramatically cut back on usage at critical times of the day or the season. By collecting information on current energy usage patterns, you can make an informed decision on whether an interruptible rate makes sense for you.
Increasingly, data collection systems take advantage of wireless data transmission. This is particularly valuable for installing sensors in existing industrial operations. Typically, the data are collected at an area wireless terminal and then transferred by conventional wire systems to the central station.
An interesting development in recent years has been the development of “conversion” sensors that can read analog devices such as gauges, convert the data to a digital signal, and transfer it wirelessly. This reduces the cost of improved central data collection and eliminates the need to interrupt electric, gas, steam or hot water lines to replace sensors.
One supplier of such equipment is Cypress EnviroSystems, which sells a broad range of industrial and HVAC data collection devices. Harry Sim from this company was also recently a presenter at a TMAF sponsored by the Energy Solutions Center.
Sim notes the suitability of the converted data for central energy management systems. “The data in digital form is shared using open industry protocols including OPC and BACnet. Also the data can be downloaded using FTP and HTTP protocols. We have been integrated with systems such as Honeywell, Emerson, Rockwell Automation, Schneider, Johnson Controls, Siemens, Trane and others.” Sim explains that the company’s Wireless Steam Trap Monitors share the same network and protocols.
With data sent to a central location, they can be tabulated and processed using a variety of systems. In some cases, the building’s comfort system has capabilities for industrial energy data collection, processing and display. More often a dedicated system is used for this industrial energy use data. Systems from suppliers such as FireBridge specialize in data collection and process management for combustion-related processes. These processes often contribute a major part of the facility’s energy usage.
In his TMAF presentation, Aaron Mason from Hawkeye Energy Solutions described the potential savings from installing an energy metering system in an industrial facility. He noted that up to a 2% reduction in energy use came from the so-called “Hawthorn Effect.” This is result of simply making management and personnel aware that a process was being implemented to evaluate facility energy use. An additional 2.5% to 5.0% percent reduction came from the ability to assign energy usage information to the appropriate department or process manager.
Mason indicated that an additional 5% to 15% savings came from improved energy use awareness, the ability to make simple adjustments and improve maintenance, and adapt to utility electric demand schedules. Finally, he said, an additional 15% to 45% savings could come from implementation of an ongoing commissioning program. Such programs make teams aware of energy consequences of equipment changes, schedule variations, and potential process and maintenance improvements. Also part of this result was increasing management attention to energy management issues.
Process Improvement an Associated Benefit
Rockwell Automation is a major provider of systems to integrate all plant operations. Rockwell places emphasis on converging production disciplines into an integrated plant-wide architecture to meet key market challenges. One of those steps is to improve productivity with better utilization of assets, including energy usage. Rockwell offers systems and hardware to support that goal.
According to Mary Burgoon from Rockwell, the benefits often go beyond energy reduction. “Customers are finding that information on energy usage can lead to other significant process improvements. Processes can be streamlined, and unnecessary steps can be eliminated.”
Burgoon notes that the data may already be collected, and the important effort is in organizing and evaluating it. “We know that today’s industrial customers are especially interested in the topic of process improvement, and collecting energy usage data is just one step. But it is an important one.”
Data May Suggest Other Changes
In some cases, information summarized with a plant energy management system may show opportunities for major plant or process changes. As an example, if it is determined that there are large and simultaneous energy requirements for electricity and steam or hot water, it might be advantageous to look into a combined heat and power plant, with on-site engine or turbine electric generation also providing significant byproduct heat for process use.
If it is demonstrated that ovens, furnaces or driers are major fuel users, it might be time to install economizers, air heaters, or other heat recovery equipment. Accurate data collection will help you calculate the payback for these kinds of energy improvements.
Key to Continuing Efficiency
It all begins with the commitment to improve by collecting data and studying the existing system. In almost every case, opportunities for major improvements will spring out from the data. Data analysis will verify the value of improvements. It is important to understand that energy management is not a one-time step, but rather an ongoing process. Those realities are your tools to a future of continuous improvement in your energy efficiency.