APPA

U pgrading or replacing a boiler system presents one of the most daunting and expensive chal- lenges a large facility can undertake. When the time comes—whether the current system is outdated and ineffi- cient or whether it fails outright—facility management must take the time to fully understand the process in order to set campus goals and make the right deci- sions to fulfill their energy and efficiency needs. Currently, a substantial number of colleges and universities, as well as over 1,200 Veteran's Administration (VA) medical center campuses, are undertaking system overhauls like this. ese system upgrades are driven pri- marily by environmental concerns. Most of these facilities will need to update their equipment, but some will require a full- system replacement. It's a huge undertak- ing—but most administrators believe that the long-term savings will make the effort worthwhile. WHY MAKE THE CHANGE NOW? One of the driving factors in mak- ing this change right away is regulatory. California, New Jersey, and Texas have implemented air-quality standards that will not be met by older boiler systems— boilers in these states must be upgraded or replaced. ese old systems often used technol- ogy that sacrificed environmental safety in favor of cost savings. Some systems incorporated metal mesh burners, which utilized filters that clog easily. e gradual clogging of air filters leads to less excess air, which leads to higher nitrogen oxide (NOx) emissions. NOx emissions are a combination of nitric oxide (NO) and ox- ygen. NO is the result of fuel combustion and alone is not considered hazardous; however, combined with oxygen, it is the source of fog, acid rain, and ground-level ozone, which has been linked to myriad health issues. And while some other systems might have utilized technology to reduce overall NOx, these systems had increased electricity costs. A second reason for a system upgrade, therefore, is to address these cost con- cerns. Today's upgrades do not require air filters, which used to add to operation costs. Upgraded systems also offer quick- change, dual-fuel capabilities, switching between gas and oil firing in less than three minutes. is saves on service costs, since multiple people are no longer need- ed to make the changeover. e greatest cost reduction, however, is in the demand for electricity; upgrades can reduce elec- tric consumption up to 60 percent. One way to realize a cost savings is by employing a system that allows one to adjust the output according to the demand. is adjustment is achieved via what is called the unit's "boiler turndown ratio," which is the ratio of the maximum heat output to the minimum heat output at which the boiler will operate both ef- ficiently and controllably. As the desired temperature/pressure point is reached, the heat source is turned down, and if the temperature/pressure falls, the heat is turned up. In large campus applications, which require boilers to operate at a low propor- tion of their maximum output, a high turndown ratio is desired, and that can be achieved with modern upgrades. Tra- ditional burners using fiber metal mesh provide a 3:1 turndown; however, with recent advancements in the field, there are now systems that can provide a 9:1 turndown or higher depending on NOx requirements. ese systems can achieve ultralow NOx emissions without the use of flue gas recirculation (FGR). www.appa.org/facilitiesmanager MAY/JUNE 2019 17

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