Optimizing school efficiency and IAQ through commissioning

View case studies on commissioning in school buildings.

Commissioning has proved to be an important strategy for enhancing the efficiency of heating, ventilation and air-conditioning (HVAC) systems. Recently, commissioning has gained importance as a tool for ensuring improved indoor air quality (IAQ) by verifying and guaranteeing adequate ventilation rates.

The Center for Green Schools was joined on Dec. 13 by Hanson Professional Services Inc., Lawrence Berkley National Lab, Parkway School District (Missouri) and Seattle Public Schools (Washington) to explore commissioning options-new building commissioning, existing building commissioning/retro-commissioning and monitoring-based or ongoing commissioning-and associated benefits for HVAC and IAQ on school buildings.

Types of commissioning

Commissioning (Cx): Cx is the process of verifying that new HVAC systems are designed, installed, functionally tested and capable of being operated and maintained. The need for commissioning is partly driven by mandates, frequently imposed by international and state codes, as well as standards set by organizations like ASHRAE.

Commissioning of new systems ensures proper function before project turnover and while still within the warranty period, prevents potential long-term issues, and optimizes performance from the outset of project design. Commissioning can have a higher up-front cost than retro-commissioning or monitoring-based commissioning, but can lead to greater energy savings over time, resulting in an average payback period of four years. Learn more about the savings in studies conducted by Berkeley Lab.

Retro-commissioning (RCx): RCx involves the assessment and improvement of HVAC systems in existing buildings. RCx is focused on identifying low-cost operational improvements to reduce energy use and improve IAQ and occupant comfort. RCx is a cost-effective building tune-up strategy with average payback periods of less than two years and average energy savings of 6%. Learn more about the savings in studies conducted by Berkeley Lab.

Monitoring-based commissioning (MBCx): MBCx uses real-time data analysis for proactive maintenance, allowing for continuous optimization of HVAC operations. MBCx often involves the use of fault detection tools that alert building owners to potential issues based on an analysis of a multitude of variables. Data collected by Berkeley Lab highlights an average payback period of two years for MBCx with an average energy savings of 9%. Learn more in this case study of Aurora Public Schools.

Learn more about how types of commissioning can help to achieve your district's energy and IAQ goals from these compiled resources and FAQs.

Case study: Parkway School District

• School profile: Suburb (large) district, 4.3% of families with income below the poverty level, approximately 16,000 students, 33 buildings controlled via a building automation system (BAS)
• Strategy: New building Cx of two schools with new units going in, RCx of three schools and use of MBCx for 10 years

For RCx efforts, the school district hired an external vendor who has led the RCx efforts in two middle schools and one elementary school. The RCx process yielded a comprehensive report that outlined two potential approaches-one with a half year payback and the other with a year and a half payback period. Included in this report were descriptions for each measure that was recommended for each building.

While two of the RCx efforts are still in progress, the district has seen overall improvements for building occupants and IAQ and energy efficiency. Before RCx was completed at one middle school, occupants had raised significant concerns about comfort, and the school was seeing a higher energy use compared to other district buildings. Upon receiving the RCx reports, the district was able to quickly turn off exhaust fans that were not tied into the BAS, adjust the scheduling of individual equipment and initiate ongoing efforts to enhance the BAS system and equipment installations, along with other issues identified in the RCx report.

MBCx is something the school district has been using over the last decade. Given the small size of the sustainability and energy department, the limited resources, and the team expertise constraints, they opted to use MBCx to analyze the large volume of real-time data coming from the building automation system and received prioritized fault detection alerts to quickly address potential issues. Outcomes from this effort include increased energy savings, comprehensive and useable reports, and the ability to integrate with other Cx projects.

Case study: Seattle Public Schools

• School profile: City (large) district, 9.8% of families with income below the poverty line, approximately 49,000 students, all new buildings are all electric (Seattle Energy Code 2018)
• Strategy: In-house re-commissioning/RCx

Seattle Public Schools has established an internal team comprised of four individuals who perform building tune-ups as a strategy to comply with the 2016 Seattle Building Tune-Ups Ordinance. An advantage to having an internal team over a vendor is the team's ability to quickly identify and address issues as they go and to use their familiarity with the buildings and systems. The team estimates that 90-95% of the problems they identify are fixed on the spot, which saves time and money for the district. Some of the items the team has been able to address include:

• HVAC scheduling
• Damper linkages
• Filters
• Fan belts
• Hot water settings
• Circulation pumps
• Variable frequency drives
• Photocells/lighting schedules
• Exhaust fans and sensors
• Duct cleaning
• Building automation control graphics updating
• Cleaning steam traps

One other way the district has been able to experience success is by aligning with state legislation that enforces code. The state of Washington has implemented Clean Building Performance Standards, standards that require buildings to meet target energy use intensities based on their type. These standards mandate energy efficiency measures and verification, and have larger penalties for those who do not comply.

Because of the re-commissioning team's work, as well as school remodels and HVAC upgrades as needed, the district is seeing a continued trend of district-wide energy use reductions even with increased ventilation to improve IAQ. Because of the success of this program, the district is interested in keeping the internal re-commissioning team going even after the building tune-up ordinance is sunsetted in 2026.

Panelists

Thank you to our presenters:

• Wade Conlan, P.E., CxA, commissioning and energy discipline manager, Hanson Professional Services Inc.
• Eliot Crowe, technology researcher, Lawrence Berkeley National Lab
• Lindsay Elliot, sustainability and energy coordinator, Parkway School District, Missouri
• Ian Brown, resource conservation specialist, Seattle Public Schools, Washington

Thank you also to our webinar sponsors, Attune and Safe Traces.

Watch the webinar

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