Fishbeck, Thompson, Carr and Huber Inc.: Ferris State University Low Load Boiler
Addition to existing building at an educational facility.
Engineering firm: Fishbeck, Thompson, Carr & Huber Inc.
2014 MEP Giants rank: 79
Project: Ferris State University Low Load Boiler
Address: Big Rapids, Mich., U.S.
Building type: Educational facility
Project type: Addition to existing building
Engineering services: Automation/controls, commissioning/retro-commissioning, electrical/power, fire/life safety, HVAC/mechanical, lighting, energy/sustainability, and plumbing/piping
Project timeline: 5/9/2012 to 2/3/2014
MEP/FP budget: $119,500
In recent years, Ferris State University (FSU) in Big Rapids, Mich., has greatly reduced its energy use by implementing selective campus improvements. These improvements have contributed to a reduction in campus steam demand and resulted in boiler inefficiency, especially during the nonheating season. The university struggled to keep the boilers online during the lowest demand periods, which led to its decision to assess the central heating and power (CHP) plant’s ability (with its current boiler configuration) to meet the campus’ current and future needs. FSU retained Fishbeck, Thompson, Carr & Huber (FTCH) to evaluate and present options for configuration changes that would cost-effectively and efficiently meet the campus needs based on current and foreseeable demands. As with most public universities, funding and space for projects are held to a high degree of accountability. To minimize the use of both, it was FSU’s wish that any added equipment be placed within the footprint of the existing CHP. In the evaluation phase, FTCH determined adding one or more steam boilers with the capability to operate at smaller loads than the current boilers would be needed to handle the reduced campus load requirements typically experienced during the nonheating season.
Along with FSU Plant Engineering, FTCH determined the peak summer campus steam demand over the last few years has ranged from 20,000 lbs/hr to 33,000 lbs/hr, and future campus development was likely to reduce the peak summer demand rather than increase it. The firm determined that a new boiler capacity of 900 hp would allow FSU to switch the total campus steam load to the new low-load boiler or boilers during the nonheating season. This switch avoids the difficulty and inefficiency of leaving the larger boilers online and presents an opportunity to perform maintenance on the large boilers. To provide the greatest level of security and optimum turn-down, FSU selected two 500 hp boilers for this use. An unused attached garage space was selected as the best location to install the low-load boilers. However, the structure and height of this space was inadequate for an acceptable installation. The university considered removing the current roof and constructing a higher roof with increased structural capacity. However, completely demolishing the current garage and constructing the new boiler space at the same location proved to be more cost-effective and provided more usable space. Boiler selection was critical to FSU’s continuous effort to reduce its carbon footprint and optimize energy use. FSU selected two, 500 hp firetube boilers with advanced combustion controls, which maintain low excess air even at low loads, and an extended surface heat exchanger design to provide optimum efficiency, even at reduced loads. With a local utility rebate, FSU justified using boiler stack economizers, even though the boilers are projected mainly for summer use. The boiler efficiency used to meet the summer steam demand is projected to increase from an estimated 75%-78% efficiency achieved by operating the oversized existing boilers to 85% with the new low-load boiler plant. Also important is the CHP’s ability to provide a reliable source of steam to meet reduced campus demand during the summer without the need to vent steam or risk a shut-down with the previous boilers.