In the Field: How Keeping an Eye on Energy Consumption Can Prevent Catastrophic Failures
There are many ways that good energy management mitigates risk, from reducing vulnerability to volatile costs and uncertain supplies to improving your company’s public image and promoting employee morale and loyalty. You can migrate to less expensive, environment-friendly sources; produce your own energy with cogeneration or on-site renewables; use it to provide employees with free vehicle charging; brighten work environments with more efficient lighting; partner with the community in district energy projects; and perhaps above all, simply reduce energy’s role in risk by using less.
One of my favorite ways is using energy monitoring to find savings opportunities, and the same monitoring system often also can reduce risk by identifying overstressed equipment and incipient failures. Here are a few examples from the field.
I got an urgent call from John, the plant engineer at the 80-acre RCA facility on Sherman Avenue in Indianapolis. A transformer had just exploded, there had been a minor fire and production was shut down in that part of the plant. Luckily no one had been hurt but it was a wake-up call. As in many big plants, they were continually adding, removing or moving production equipment in response to market demands. The plant was old and much of the electrical system had been there for many years. Like a lot of older facilities as well as many newer ones, there were no accurate “as-built” records for the electrical system. John had no idea that one of the transformers was overloaded until it exploded. As a result there had been a near disaster and with production shut down for a few days, the incident had cost them a lot of money.
“Can your energy monitoring system be expanded to monitor the loading on all of my big transformers?” he asked. He wanted to be able to watch the loading in real time and have a permanent record to help him make decisions about locating and supplying power to the constantly changing equipment. Think of the costs and trouble he could have avoided had he been monitoring the loads before that incident. “Sure,” I replied. We added the necessary points.
The plant engineer for a huge Kosmos cement plant in northern Kentucky called me one day with better news. He said, “Your monitoring system just saved me $100,000 in one day! I detected a rising amperage on a 3,000 hp motor, shut it down and an inspection showed that we had avoided a catastrophic failure that would have cost us more than $100,000.” I think the monitoring system had been in the plant for six months or so. When they had purchased the system, we had signed a guarantee that they would recover the cost of the system from documented energy savings alone within 12 months.
The actual costs were recovered within the first six months by reducing the peak demand 2,250 kW and the consumption 200,000 kWh per month through a combination of no-cost changes in operation and control. Combined with the $100,000 avoided cost of a motor failure, the owner had realized more than 200% return of their investment within the first year.
Air Conditioning/Dehumidification Systems
In two different facilities, monitored data showed direct expansion (Dx) refrigeration systems in large rooftop air conditioning and dehumidification systems running out of control with coils freezing, compressors shutting off as a result of anti-freeze thermostats, and then cycling back on as the coils warmed and began to thaw. Compressors that were designed to cycle off and on five or six times an hour were cycling three or four times a minute and destroying themselves.
In one case, the problem resulted in part from the minimum capacity of the equipment being so much larger than the actual cooling required by the conditioned space. In an effort to keep the unit running, a contractor had set a 100 kW electric heating coil to run 100% of the time, more than doubling the utility costs of the HVAC systems and destroying at least one compressor. The system was modified to reduce its minimum cooling capacity.
In the other facility, the large built-up dehumidification system had been poorly designed more than 10 years before with the components mismatched. In an effort to keep the system functioning, a different contractor had set the cold deck to the minimum temperature causing the direct-fired natural gas re-heater, the largest energy user in the facility, to consume five times the amount gas that it should have. The resulting short cycling of the oversized compressors had destroyed at least one compressor during that period.
Compressed Air Systems
In a GE plant in Louisville with 15,000 hp of air compressors, monitored data showed a large variation in compressor efficiencies and further investigation showed a number of control or maintenance problems that were not only increasing the operating costs but shortening the lives of the huge machines. Control sequences were modified and the system efficiency was increased 20%, saving more than $250,000 annually. Compressors were repaired and monitored continuously to keep them running at peak efficiency.
A Mariah meat-packing plant was getting ready to spend $200,000-plus on new electrical transformers and more chillers because they could not cool the plant adequately on hot days. The risk and liability associated with failure to adequately cool their product seemed to give them no other choice. I got a call from the engineer for the local electrical company, who knew that data from our monitoring system showed they had plenty of capacity and didn’t need to spend that money.
We found that bad valves in the old ammonia system were leaking and stealing 80% of the system capacity. Data showed that repairing or replacing the valves would give them 250% of the tonnage they needed with the existing equipment and transformers, a 150% reserve on a design day. The huge expenditure for new equipment could be avoided.
Everyone who had worked on the old system had missed the problem, but most were convinced that, regardless of the cause, the solution was to add more cooling. I had to go all of the way to the president of the company to stop the project. Without the data from the monitoring system I might have missed both the problem and the solution.
We have detected a number of cooling towers over the years that were unable to produce the required return water temperatures under design conditions. Some of the towers were fouled and plugged from inadequate water treatment or neglect. Some had broken, disconnected or improper controls, while in one case the 1,000-ton tower had been piped wrong when it was installed 10 years before. Whatever the cause, the result was high tower return temperatures causing the chillers to run at higher pressures with lower efficiencies and to work harder, use more energy and shorten their lives. Fouled towers that are not a problem during cool weather have the potential to shut down production on a hot day and cost an owner hundreds of thousands of dollars. I have found more than one tower that was destroyed 10 years before its rated life due to improper chemical treatment.
Use Real-Time Data to Make Real-Time Decisions
For little additional cost, an energy monitoring system can be much more than the box scores in the newspaper the day after the game. A well designed energy monitoring system can provide an accurate, continuous, unbiased energy audit, a continuous commissioning system, a way to ensure that energy systems are working properly, a way to ensure that energy systems are running efficiently, a way to be notified the instant something goes wrong, a way to accurately predict savings from possible energy projects and a way to verify savings from actual energy projects, size equipment and much more.
Now that more people are becoming interested in monitoring energy consumption and a whole range of new submetering and software tools are becoming available, they really need to understand that reducing energy consumption may just be the tip of the iceberg in terms of all the benefits, savings and avoided costs that monitoring done right, can provide to an owner.
Using actual real-time data to detect and alarm potential risks or failures allows an owner to become proactive. Rather than reacting to expensive failures, they can be prevented. The value of avoided costs is often overlooked because avoided costs don’t show up on the balance sheet. It’s hard to put a value on a transformer that never exploded, fires and injuries that never occurred, production that was never lost or equipment that didn’t have to be replaced 10 years before it should have. But hidden problems, risks and costs that can be avoided through proactive and continuous monitoring of energy systems can make the difference between a well run, relatively trouble-free facility and one that puts the operators and occupants in the position of spending considerable time, energy and dollars reacting to problems.
Join the information age, the 21st century, and use actual, monitored real-time data to reduce your costs, your risks and to run your plant more effectively, efficiently and profitably.
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