Energy System Monitoring is Critical for Effective Operation
Like other professionals, engineers in the energy services sector take pride in a job well done. We know we’ve been successful when we’ve helped end-users not only cut costs, but also reduce energy consumption, create a healthy and comfortable space and contribute to a more sustainable world.
Unfortunately, however, we sometimes see our work undone. It’s frustrating, and it occurs when our clients fail to conduct basic equipment maintenance and monitoring.
It’s like a luxury car company that has just sold a high-performance vehicle only to find out later the new car owner ignored the maintenance schedule for oil changes specified in the owner’s manual, and now the car needs a new engine.
My segment of the energy services world is called the “MUSH” market, which stands for municipalities, universities, schools and hospitals. Fortunately, these markets have become very attuned to the need for and benefits of facility-wide energy efficiency retrofits. But, after the project is built, regular energy system monitoring is essential.
With MUSH clients, one of the most common energy equipment maintenance failures is the failure to monitor outside air dampers in air-handling units. Dampers bring air into the building space for cooling, heating or ventilation.
Broken linkages that connect the actuators to the dampers can make the dampers useless. A damper that doesn’t close properly can introduce too much outside air into the facility. On the flip side, a damper that doesn’t open properly leaves a building with inadequate levels of outside air. The proper mix of air sources is dictated by local codes and by American Society of Heating, Refrigerating and Air-Conditioning Engineers standards.
Where the weather gets cold, facility staff need to ensure the proper functioning of freeze stats, the temperature-sensing devices that help prevent coils from freezing.
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Sometimes outside air dampers are not operating properly, or are not operating at all, because no one has been paying attention to them. And if outside air dampers aren’t working, the spaces they serve can become over-ventilated or under-ventilated, which can create major heating and cooling inadequacies.
We generally advise clients to inspect and test outside air dampers at least quarterly using the Building Management System available to them. Failure to do so can set in motion a succession of cascading cost impacts facility-wide, with levels of energy spending running as much as 20 % higher than necessary — all because a faulty damper couldn’t respond to commands being sent through the energy management system.
Poor monitoring of air handling units can not only lead to excess consumption of energy and its rising costs, it can also lead to turmoil and emergency conditions within a facility.
At one New York State healthcare facility serving elderly patients, every air-handling unit had air dampers that were in bad condition. Dampers were missing linkages and controls weren’t working. Freeze protection devices failed during very cold temperatures.
Outside air dampers that were not operating properly meant that the healthcare center couldn’t keep the units from turning off freeze protection functions. This resulted in a significant loss of productive time for personnel who were forced to continually switch on units manually.
Things got worse. At one point, a heating coil broke, causing large-scale flooding. Facility staff was pulled from their normal, day-to-day duties and spent an entire day cleaning up. Meals and medical services, and even patients, were disrupted.
It was a near-disaster that triggered substantial, unbudgeted costs for personnel, services and repairs, all of which could have been prevented if the facility had regularly monitored its dampers. The disrepair would have been uncovered and a contractor could have installed new dampers and controls. The heating coil would never have been lost.
That’s why it’s critical for energy services personnel to ensure that clients understand the importance of regular maintenance. Engineers have a duty to communicate a clear schedule of monitoring, to orient operations staff to the importance of maintenance, and to go the extra mile to make sure end-users stick to the schedule.
We’ve done our job to devise and implement a great energy management system. We’re justifiably proud of what we’ve accomplished.
We also need to impress upon our clients they need to do their share to keep the system operating effectively by visually inspecting all building operations equipment — and by remaining aware of, and responsive to, building management system alarms and equipment maintenance requirements.
Ronald Okonkwo is a licensed engineer with ConEdison Solutions in Valhalla, N.Y.