High Performing Buildings - Summer 2012 - (Page 69)

Lessons LeARned The design and construction of this project provided the opportunity for the design team to challenge methods used for decades and ask “Does it have to be this way?” In many cases the team entered into a game of how to make it better without costing signi cantly more, learning how far we could push the design and how far we could push the construction process. A few of the lessons learned include: outside Air economizer. The team was unable to include an air-side economizer in the design due to severe limitations on available duct routing space, ceiling cavities and locations for intake/relief louvers given that this was a historic building and the outside appearance was important. Because it was a historic renovation, we weighed the impact of the energy savings with an economizer against the historic cost to the building. Ultimately the energy side lost because history was more important than dropping the ceilings below the tops of the historic window elevations to t the ductwork. We did route the ASHRAE Standard 62.1-2007 minimum outside air to each zone, and managed to nd paths for this smaller duct in lieu of routing duct sized for 100% of the supply air volume. standby Mode savings. The amount of energy savings from the heat pump standby sequence varies widely. Some areas of the building never go into standby due to the nature of their use and habits of the occupants, while other spaces are commonly in standby mode when the occupants are out of the building at meetings or traveling on business trips. (In many cases it is possible to determine who sits and eats lunch at their desks and who leaves for lunch just by reviewing the trend logs.) Lighting Adjustments. After initial programming of the lighting controls and owner move-in, it was discovered that in most cases the occupants had their lights dimmed to about 70% of full output. Seeing this, the lighting controls were adjusted so that when the occupancy sensor triggered the lights to turn on, the lights would resume their prior light level and not default to 100%. Commissioning Is Key. This project was fully commissioned and included the typical HVAC systems, but also included building envelope. The envelope was closely monitored during window installation to make sure that ashing, sealants, tapes, etc., were all properly installed. It took several iterations from the construction team to nd the best method of sealing the new windows against the 150-year-old brick openings and reducing water and air in ltration. As part of this process the building was tested with a blower door to reveal areas of air leakage. The entire design and construction team went running through the building to nd the leaks and found that exterior door sweeps were leaking due to never being adjusted after installation. The test also showed that the cut in the seals around the door closers at the top of the door were an area of leakage that needed attention. The building passed with ying colors. However, the team wanted to make sure the building was as tight as possible to prevent in ltration. Controls Programming Validation. In many cases when a building is turned over, it is assumed that owner training takes place and everything works as intended. This project allowed the team to follow the building for a full year after move-in and monitor on a weekly basis remotely via the BMS. In a few cases the team found programming items that were overlooked, controllers that were not maintaining tolerances, and scheduling items that needed tweaking to optimize energy use. This was not a dif cult task, but just required the time to do it. leakage areas and address them was also part of the commissioning team’s approach t o get the building as tight as possible. The design concept of the HVAC system was simple: use energyefficient systems that physically fit in the limited building space and maximize the use of control logic to minimize the need for energy. Simple concepts such as using occupancy sensors to control setback periods and optimizing schedules to meet actual needs rather than assuming that the design team knew the operations of the building all went into creating a design that is efficient and makes sense. The design team spent a day with the owner’s facilities staff to review all of the sequences to make sure that they meshed with the use and maintenance of the building. Taking the time to sit down and rethink the design approach, and optimizing pipe routes, duct routes, type of motors, etc., all added a few cents here and there, but ultimately contributed to the bottom line savings. After completing this project, the design team and owner now realize that the concept of just meeting energy code minimums is a good goal with renovations, but there is no reason to stop there. While it is easier to make a new building high performing, this Summer 2012 HIGH project demonstrates that the existing building stock can significantly improve energy performance. • References 1. “Lamp Specification and Application Guide 2011.” Philips Lighting Company. 2011. 2. “Commercial Building Energy Consumption Survey.” U.S. Energy Information Administration. 2003. http://tinyurl.com/eia-cbecs. About the AuthoRs Michael Lubbehusen, PE, Member ASHRAE, is a principal at Primary Engineering in Fort Wayne, Ind. Terry Thornsbury, AIA, LEED AP is president , of Viridian Architectural Design in Fort Wayne, Ind. PERFORMING BUILDINGS 69 http://www.tinyurl.com/eia-cbecs

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High Performing Buildings - Summer 2012
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High Performing Buildings - Summer 2012