Colorado’s Broomfield Heights Middle School, the first of five schools in the Boulder Valley School District (BVSD) to undergo a deep energy retrofit, is operating more efficiently than projected with annual cost avoidance of $19,000.
Last year, BVSD and McKinstry, a construction engineering company, embarked on a sustainable energy program, aiming to reduce energy usage by half in five district facilities to reach net-zero capability. Net-zero capability is achieved when the amount of energy generated through on-site renewables is equal to or more than the energy consumed by building users. For Broomfield Heights Middle School, it is reached at a rate of 35.0 EUI (Energy Use Intensity).
A $576.5-million bond, approved by voters in 2014, is funding many projects throughout the district, including McKinstry’s, which consists of a mix of five deep energy retrofits, one recommissioning retrofit and six new-construction projects. The combined energy measures are expected to curb the district’s utility costs by $307,000 annually while decreasing greenhouse gas emissions and the district’s carbon footprint.
The 107,750-square-foot, two-level Broomfield Heights Middle School, originally constructed in 1983, was projected to reduce its EUI from 60.7 to 43.4 in the first year of performance after facility improvements were implemented. Throughout the course of the first year, the building consumed less energy than predicted and ended the year with an EUI of 36.6, even with added air conditioning, improved ventilation rates, and increased total operating hours.
McKinstry began work early in the development phase, beginning with an audit of the building to develop an energy model, which is used to predict building performance after the construction period. Facility improvement measures include building envelope upgrades, LED lighting upgrades, and an entire HVAC system retrofit that integrates chilled beams with heat recovery systems.
McKinstry used its Active Energy Management (AEM) program. Energy Manager Today interviewed Greg Spalding, P.E., LEED AP BD+C, CEM, with McKinstry.
The school surpassed predicted savings levels. What do you attribute this to?
The additional savings can be attributed to a few things, first off, was our continued involvement into the operational phase of the project through our Active Energy Management service, which allowed our commissioning engineer, James Johnson, to continue to monitor and recommend improvements on the overall operation of the facility over the first year of performance for the facility. Secondly, the facilities staff at BVSD was integrated into our Active Energy Management program, and with their technical ability to implement change, we worked together to make continued operational adjustments to the system to further enhance the buildings performance. These operational enhancements include such things as more proactive scheduling based on the actual usage of the facility, increasing or modifying operating setpoints that drive additional savings above and beyond the baseline setpoints that were originally designed and commissioned.
The press release says that the school building underwent envelope upgrades, LED lighting upgrades, and an entire HVAC system retrofit. Can you provide a bit of specifics on each of these?
The mechanical system underwent a complete retrofit for most the building. The mechanical system was converted from a two-pipe fan coil unit system, with heating only, to a four-pipe chilled beam system with cooling added. The chilled beam system consisted of active beams with ventilation air provided by dedicated outdoor air units with energy recovery. The building envelope upgrades consisted of a new roof that increased the insulation R-value of the overall roof assembly. LED lighting upgrades were completed in most of the facility, which not only decreased the lighting energy consumption, but also drastically improved the occupant comfort, by illuminating the dark hallways on the basement level with the LED fixtures.
Why is this news important for energy managers?
This news is important because we aren’t discussing expected or modeled results, we are discussion ACTUAL results. This project profile takes a purposefully planned integrative design approach and shows that with the right team, and the right plan, energy efficiency can be incorporated into a successful project, with modeled results that can be exceeded, and not just met. Many energy efficiency projects are assumed to have saved facilities energy over time, but most do not have the ongoing operational verification and technical oversight during a performance period to verify a successful outcome.
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