Perham-Dent Public School DistrictPerham, Minnesota
Energy-Efficient Replacement Facility
Over the last decade, the City of Perham, Minnesota, has committed to modernizing its educational facilities to meet 21st-century standards. Faced with numerous infrastructural challenges, their century-old high school was burdened with an outdated steam heating system in dire need of replacement, poor indoor air quality, inadequate natural lighting, and inefficient energy usage. To address these critical issues, the community decided to build a new state-of-the-art facility. Opening in 2018, the new Perham High School is not only exceptionally energy-efficient but also provides optimal indoor air quality and occupant comfort.
Project At A Glance
Size: 158,000 Square Feet
Completed: 2018
Baseline Energy Use: 85 EUI
Performed Energy Use: 39 EUI
Awards
ASHRAE International Technology Award
The Challenges
Design an energy-efficient, fully electrified school on budget
Prioritize occupant comfort, health, and wellness
Create a community-focused learning environment with flexible education spaces
The flexibility and openness [of the new building] sets us up a lot better for educating today's kids and moving forward...it's going to be the heartbeat of the community for a long time.
Mitch Anderson
Perham-Dent Public School District Superintendent
The Solutions
The district prioritized long-term energy efficiency for the new facility. In line with these goals, CMTA conducted a thorough analysis of the building to ensure that energy modeling would result in the most efficient and user-friendly space. Given the building’s location in Climate Zone 7, achieving optimal energy performance required careful consideration of the building’s envelope and HVAC systems. During the project’s initial phases, a central heating and cooling plant was implemented to centralize the equipment and pumping systems. Initially, this comprised a boiler and chiller plant. However, as the project team began to discuss energy efficiency and geothermal operation with the district, the project evolved to include a geothermal wellfield along with a 6-pipe geothermal heat recovery chiller to provide heating and chilled water to the building. This innovative solution allows the building to share energy internally before utilizing any energy from the wellfield, significantly improving energy efficiency. When comparing energy models, the new building’s overall energy use was reduced by 41% by shifting from the initial boiler and chiller system to the newly selected 6-pipe geothermal heat recovery chiller.
In addition to whole-building strategies, the team implemented individual room strategies to further optimize energy use. Classrooms were designed with daylighting zones to utilize natural light, reducing the facility’s reliance on artificial light. Occupancy sensors were also installed to decrease light and airflow levels when rooms are unoccupied. These strategies reduced the already impressive light power density of 0.64 w/ft2—35% better than the code minimum 0.99 w/ft2—by automatically adjusting throughout the day as students move around the building.
Operating at 39 EUI, the new building showcases an impressive 54% improvement in energy efficiency compared to the previous facility’s 85 EUI, despite housing a large athletic complex, a commercial kitchen, and a Vocational Tech area with high-demand systems like welding and wood shop exhaust systems. CMTA’s sister firm, ICS, a Legence company, provided commissioning for the project, ensuring the MEP systems were implemented as designed to achieve performance expectations.
Occupant Comfort, Health, & Wellness
Perham, MN, experiences dramatic climatic extremes, with winter temperatures dropping to -19.8°F and summer conditions reaching a humid 87.6°F dry bulb and 71.1°F wet bulb. This creates a challenging environment in which to design an HVAC system that is both comfortable and energy efficient. Accordingly, the design team took pivotal steps to create quality and comfortable spaces for students and staff. Air handling units incorporate outside airflow measuring stations that monitor and ensure the proper amount of outside air is provided across all supply fan speeds. MERV 13 filtration, coupled with CO2 sensors in the classrooms and return ductwork, enable Demand Control Ventilation strategies to dynamically adjust air supply based on occupancy and activity. This flexibility not only contributes to a healthier environment for students and teachers but also optimizes energy use by adapting to specific space and building needs.
To maintain comfort during high humidity days, a dehumidification sequence with space tempering provides air that maintains a comfortable learning environment. On cold days, in-floor radiant heating in external ground-level rooms offsets the external load and reduces energy use by the overhead variable air volume system, preventing air stratification caused by overhead diffusers.
Cost-Effective Geothermal Design
From the project's onset, CMTA worked to enhance energy efficiency by optimizing daylighting, ventilation, and temperature controls while also considering both initial costs and recurring utility costs. As the design team refined the energy model and geothermal wellfield sizing, they achieved a 7% reduction in the total bore hole length needed. Moreover, by incorporating an auxiliary boiler for peak days, they achieved an additional 23% reduction in bore field length. This reduced wellfield fulfills around 98% of the required energy transfer during the heating season, with the boiler supplying extra heat on peak days. This strategic reduction in total bore field size led to significant cost savings of $180,000 in drilling and piping.
The Results
By transitioning from a century-old, steam-heated building powered by natural gas to a fully electrified facility utilizing geothermal heat pumps, Perham-Dent Public School District has made significant strides in both energy efficiency and environmental sustainability. Though the new facility has a 32% greater floor area than the previous high school, it consumes just 46% of the energy required by the century-old facility. This remarkable achievement is further underscored by a 15% reduction in carbon emissions.
CMTA was proud to work with our fellow Legence company, ICS, to design and commission this high-performance facility that will serve the Perham community for years to come.
This building is about the future. We’re not only preparing our students for the future, but we’re also designing this building for the future by using the earth respectfully and efficiently to power the school.
