Bellevue School District Modernization Plan

Starting in 2002, the Bellevue School District (BSD) began replacing and updating schools that no longer met the needs of their growing community. BSD’s goal with each new school is to exceed energy design requirements as defined by the 2012 International Energy Code. As of 2018, BSD has replaced 18 schools with state of the art facilities that incorporate the latest educational designs and technology to ensure students and teachers have an ideal learning environment. By making each new school as energy efficient as possible, BSD is ensuring they are maximizing their capital dollars which will allow them to make the best use of their general funds. In 2015, as part of the ongoing modernization projects, Enatai Elementary was demolished to make way for an updated facility that will host elementary students well into the future.

Unified Lighting and HVAC Control

BSD is determined to improve upon school designs with each facility replacement. When planning for the new Enatai, BSD decided their next improvement would be to house as many of their controlled systems under one platform as possible. Having worked with ATS Automation for many years, BSD was familiar with the environmental controls provided by the Alerton building management system (BMS) from their other schools. Once ATS demonstrated that they could efficiently control the HVAC equipment and also incorporate all the lighting into the same BMS, BSD chose ATS to provide the HVAC and lighting controls for the Enatai facility. By selecting one vendor, staff at Enatai have access to ATS’ expertise for both HVAC and lighting during the original installation and for long-term service. Now Enatai has one point of contact when it comes to the controls for their school — simplifying maintenance and operations.

To integrate HVAC and lighting, ATS designed a system utilizing Alerton’s Compass BMS and Blue Ridge Technologies’ (BRT) lighting control platform. Alerton and BRT combined provide integrated lighting control without the use of proprietary gateways. Utilizing BACnet, BRT controllers are easily added to the Alerton BMS without needing any integration device. This solution allows BSD operators to use the same schedules for both HVAC equipment and lighting without the need to duplicate work in a separate lighting interface.  ATS programmed a global schedule for lighting at Enatai in conjunction with BRT monitoring classrooms and common areas using occupancy sensors and photo cells. The sensors are used for daylight harvesting and turnoff or dim lighting according to lumen levels and whether the area is occupied or not. Classroom lighting control features a traditional on/off switch in the front of all classrooms, as well as a separate adjustment panel near the teachers’ desks.

Impact on Energy & Operations

By combining environmental and lighting controls, BSD has ensured that their high efficiency designs and equipment will continue to save the school money throughout the life of the building. “The strategy is that on day one the facility is already saving on utility bills,” said Jeff Tweeten, HVAC/Utilities Control Specialist for the Bellevue School District, “by saving on day one, the measured benefits are all about the efficiencies that directly impact the learning environment.” With integrated lighting, Jeff and his team can focus on what really matters  — ensuring the learning environment is optimal for both students and teachers.

The new Enatai Elementary nearly doubled the size of the original school to 87,500 square feet. The school opened to the public in September of 2016 with over 500 students attending class during the academic year. The school also received $135,013 in utility incentives by Puget Sound Energy (PSE) for exceeding local energy code efficiency requirements and standard practices during construction.

In addition to lighting and environmental controls, the new Enatai elementary school features other energy efficient technology, such as geothermal heating and cooling, solar panels, heat recovery, AstroTurf, solar hot water loop and high efficiency sequences for mechanical equipment. Utilizing solar panels, Enatai recovers approximately 90,000 kWh per year. This harvested energy covers the majority of the school’s lighting cost for the year. Enatai’s energy use index (EUI) was also significantly improved from the previous facility. The school’s combined electric and natural gas EUI is currently 17 and is expected to decrease as system tuning continues. The national median source EUI for K-12 schools is 141. ATS, along with Alerton and BRT, help Enatai maintain optimal performance with rock solid building controls and sequences, along with occupancy-based lighting usage and daylight harvesting.

For additional details read the entire case study detailing the work performed at Enatai Elementary.

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Bainbridge High School (BHS) is Bainbridge Island School District’s only comprehensive high school. The school serves approximately 1,300 students in grades 9-12. BHS has been recognized by US News & World Report as well as Newsweek Magazine as one of the top schools in the United States. Both publications rank the school as #5 in Washington State and #247 (US News & World Report) and #201 (Newsweek) in the nation. BHS boasts a graduation rate of 95.2% and is a magnet school for transfer students and families looking for a school that prioritizes making every student college and career ready. This stellar reputation not only applies to BHS students and teachers; the facility team is also constantly on the lookout for projects and programs that will save the District money and enhance the learning environment of the school. With the mandate to find projects that will put savings back in the District’s general fund, Bernard Mejia, Maintenance Lead for the District, and his team proposed replacing the aging and failing boiler controls for BHS to save on utility costs, reduce equipment run time and improve overall facility functionality.

Boiler Retrofit

The boilers, installed in 1998, for BHS had been oversized in the anticipation of a plant expansion that never occurred. The size coupled with the aging boiler control board had led to a degradation of the HVAC system, causing poor functionality and operation of the plant. The system pumps, and other equipment, were running 24/7 and the night setback had stopped following a schedule. To control the boilers, the District staff had manually overridden them to operate in low fire mode in order to stop them from short cycling. To address what they felt was wasteful equipment operation, Mejia and his team developed a project plan around modernizing the boiler control to save on propane and electrical use.

To improve energy usage at the school, the District teamed up with ATS Automation to replace the original boiler controller, as well as program and tune the system with energy savings in mind. The original Siemens boiler PLC was replaced with Alerton’s VLC-1688 programmable controller. Boiler control was then integrated into the existing Alerton system for District staff to be able to schedule and troubleshoot from their centralized BAS.  Additionally, a new operating sequence for the 3-way valves was developed, night setbacks were initiated and an aggressive scheduling plan was implemented. Now the pumps run on a schedule instead of operating 24/7, as they had been before the project was complete. The District also limited the number of individuals that could schedule the system. Now there are only two individuals in charge of scheduling the schools which has reduced the chance of the buildings running while unoccupied.

Savings

This boiler control project was completed over the summer of 2014. When comparing the high school’s utility cost from 2014 to that of 2015 there was a 36% decrease in spend. This decrease was equivalent to $267,540 in utility savings that was put back into the District’s general fund. In addition to reduced spending, equipment runtime decreased by 42% when comparing the winter months of 2014 to 2015.

By having ATS install and integrate the new boiler control into the existing Alerton building automation system, the District re-established control over their boiler plant while leveraging the existing control system and extensive control knowledge of ATS engineers.

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Located in downtown Renton, WA, the historic Renton High School (RHS) was originally built in 1911. The initial building was later demolished to make room for an updated school with improvements and additional space for the increasing population of the area. Over its 105-year history the high school has been rebuilt and expanded upon many times. The latest improvements began in 2013 with a complete controls retrofit of the RHS Campus.

Controls Retrofit

ATS designed and installed a complete DDC retrofit, replacing a poorly commissioned and legacy control system with Alerton I/O controllers and global controllers along with a Niagara AX Supervisor front-end to conform with District standards. In addition to the controls retrofit, ATS also installed CO2 sensors to enable demand control ventilation strategies. According to J. Stine, Program Manager for the Renton School District’s Energy Management Office, an element that made this project such a success was the planning and gathering of input from the maintenance staff. Now RHS has a fine-tuned, commissioned and fully functional system that provides a standard for all facility improvements to come.

Savings and Energy Usage Reduction

As a result of the DDC retrofit RHS has had a dramatic drop in energy consumption and cost. Just over a three-year period, energy use has dropped 37% and cost has decreased 32%. District energy use intensity has decreased from 74.4 kBtu/sqft to 38.3 kBtu/sqft, a reduction of 49 percent.

The following chart illustrates the District’s energy usage over a three-year period compared to the school-year baseline. Substantial completion of the project was achieved during the summer of 2013.

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