Energy Savings: Insights and Innovation

daylighting in classroom

PHOTO © SELSO GARCIA

According to the U.S. Environmental Protection Agency (EPA), the cost of energy is the second highest operating expense for school districts around the country after personnel. Furthermore, the EPA estimates that 25 percent of energy use in schools is wasted. As U.S. schools continue to face increasing budget pressures, implementing strategies for energy savings can have a significant positive impact on the bottom line for school districts. By implementing policies for energy use reduction in new construction, renovation as well as in building operations and maintenance, school districts can direct much-needed funds to student services and personnel.

Effective use of bond dollars in new construction and renovation provides the greatest impact on energy savings over the life of a building. Energy efficient, sustainable design must be incorporated from a project’s inception to be most effective in decreasing life cycle costs. Site selection, building orientation, mechanical systems, efficient building envelopes and low-maintenance materials are some of the key considerations in campus design.

Additionally, the use of energy modeling early in design can help inform big picture design decisions from the outset regarding orientation and sunlight. Finally, close collaboration between the architect, consultants (i.e. MPE engineer, structural engineer, civil engineer) and contractor fosters good communication and helps to ensure a whole systems approach to the design.

school from the street

PHOTO © INDEPENDENCE PROFESSIONAL PHOTO

Seeing the light

According to the EPA, artificial lighting consumes an average of 25 percent of a school’s energy. Being considerate of the mix of artificial and natural lighting in school design can have a significant impact on energy costs. Automatic daylight harvesting, vacancy sensors and dual controls in the classrooms limit the number of switches users need to control. In recent years, LED lighting has become more competitive in cost when compared to fluorescent lighting at a fraction of the energy cost. Dimming is more easily incorporated in LED systems and additional wiring costs are minimized.

In addition to looking for ways to minimize costs in artificial lighting, priority should also be placed on designing to maximize natural light in schools. Natural light in classrooms has been shown to increase test scores and student focus. In fact, a study by the Northwest Energy Alliance found that students in rooms with the most diffuse and glare-fee daylight improved performance on standardized tests by up to 26 percent.

hallway learning center for sustainability

PHOTO © CHARLES DAVIS SMITH

Air and Temperature Control

After lighting, mechanical systems account for the most energy usage in buildings. Additionally, high-quality indoor air has been shown to have the greatest effect on student performance and attendance along with natural lighting. HVAC system selection should take into account the size, shape and program of the building. There are many different mechanical system types available. The best system is the one that: 1) can be properly maintained by the district maintenance staff, 2) is energy efficient, 3) will fit the site constraints and 4) will meet the budget limitations of the project. With any mechanical system type selection, it is important to be sure to meet or surpass the minimum outside air ventilation requirements for the space. This outside air requirement often places the largest load on HVAC systems and needs to be considered as an integral part of any system. Pre-treat systems, energy recovery ventilation, and return air tempering should all be taken into consideration.

Some of the more energy efficient systems utilized in the Southern United States include Geothermal (Ground Source) Heat Pumps and Variable Refrigerant Flow (VRF) systems. However, these systems can sometimes be more expensive to incorporate. Some of the less expensive, historically less efficient HVAC systems such as packaged Roof-Top Units (RTUs) now have options for significantly higher efficient equipment offerings. Instead of settling for 13 Seasonal Energy Efficiency Ratio (SEER) efficient RTUs, higher efficient 20-23 SEER units can be installed for a minor cost increase per unit. Through the use of variable speed motors, multi-stage compressors, and other improvements, these new systems can make a dramatic difference in a building’s energy usage, especially in an equipment replacement project.

hallway learning center for sustainability

PHOTO © CHARLES DAVIS SMITH

After careful siting of the building and selection of appropriate lighting and HVAC systems, the building envelope itself has the potential to save energy dollars. High performance walls, openings, and roof assemblies are continuously improving through code requirements and competition. Building codes are requiring not only higher R-values in roofs and walls, but also continuous insulation (unbroken by studs or framing) for new construction. New technologies such as Insulated Concrete Form (ICF) walls can be considered as well.

Insulated Concrete Form exterior walls (ICF) are being more widely used in school design. This system is composed of two layers of rigid insulation formwork, which is filled with a layer of concrete poured in between. These walls provide up to an R-40 insulation value, reducing heating and cooling loads significantly. They reduce indoor allergens by limiting air infiltration and allow for a quieter indoor environment. ICF walls are inherently more rigid and durable when it comes to impact resistance, providing greater protection from tornadoes, hurricanes and fires. The concrete also has a longer lifespan than conventional wall construction, creates less waste and increases the speed of construction beyond the typical pace for CMU or stud framed construction.

In conjunction with the wall assembly, a designer should evaluate heat transfer through the roof, crawl space and window openings. These should have an R-value that is complementary to the walls for the overall envelope to be the most effective. Consider increasing the roof insulation design from R-20 to an R-30 highly reflective roof in order to ensure the energy efficiency of the roof approached that of the high performing walls. Proper flashing and sealing of windows reduces air and water infiltration. It is also important to select glazing with a low solar heat gain and shading coefficient. For optimal performance, exterior sun control should be provided on openings through the use of louvers, sun shades, and overhangs.

Frisco ISD’s Independence High School designed by Corgan, is a 2,100-student comprehensive high school designed with insulated concrete form wall construction. In combination with a geothermal heating and cooling system, LED lighting, and careful building layout and siting, the campus uses over 50 percent less energy than Frisco ISD’s similar-sized Centennial high school, built eleven years prior. The district has opened an additional nine other ICF schools since 2014, and has four more currently under construction.

construction of school walls

PHOTO COURTESY OF CORGAN

Sealing the Envelope. Insulated Concrete Form (ICF) exterior walls provide high R values and continuous insulation due to the lack of studs and framing. They are becoming more common in school design. The ICF system is composed of two layers of rigid insulation formwork that is filled with a layer of concrete poured in between. The walls provide up to an R-40 insulation value, reducing heating and cooling loads significantly. They reduce indoor allergens by limiting air infiltration and allow for a quieter indoor environment.

It Takes a Village

When developing district standards for building construction and maintenance, one should do so in tandem with the staff “holding the tools.” The staff knows the school best; they should be included in design development and trained on new technologies. “Education is key to empowering maintenance staff,” says Jerry Palermo, energy manager for Grand Prairie Independent School District. “Understand that after all the engineers and contractors are gone, they are the ones that have to care for the building.”

A successful energy management plan involves not only maintenance and operations staff, but also administrators, teachers, students, the community and designers. Education and awareness are powerful tools to create buy-in from everyone. Clear goals and baseline analysis allow for clear measurement of savings over time. To aid in this effort for their district, both Frisco ISD and Arlington ISD have developed websites where students, staff and the community can view detailed data regarding water, natural gas and electricity consumption of the district’s buildings. Sustainable practices and systems can also be impactful teaching tools for students. Leaders should provide transparency to students and teachers as to the power usage they generate.

Systematic energy audits can also be effective in reminding users of the impact they have to control energy costs. Eliminating microwaves, space heaters, refrigerators and printers from classrooms, turning off computers and lights throughout buildings and dialing back the thermostat during off-peak hours have a big effect on the bottom line. A staff member should walk every roof a school periodically to ensure their school is not underperforming.

construction of school envelope

PHOTO COURTESY OF CORGAN

Finally, paying attention to the energy bill is important. One should compare current trends with those from the past to set a baseline for energy saving strategies and potential audits or facility upgrades. To aid in this comparison, energy consumption meters can be provided at the main electrical, water, and gas service to a facility and monitored to closely track consumption. Energy penalties can be incurred without notice, such as when a school’s power factor drops below a certain power quality percentage (usually below 90 percent). Power factor capacitors allow a building to utilize power more efficiently and pay for themselves quickly by reducing penalties from energy providers.

Maintenance is Key

A 2011 McGraw-Hill study noted that the average age of school buildings in the United States is 42 years — which is nearly the expected serviceable lifespan of a school building. Facility assessments can help to determine whether pouring additional money into an existing building will pay off in the long run. Depending on the extent of work proposed, existing building codes may require increasing the amount of outside air into the building (potentially requiring new air handlers and increased duct sizes), upgrading lighting controls and fixtures and upgrading plumbing fixtures to meet new water usage standards. Administrators should use renovations as targeted opportunities to upgrade existing systems for greater performance over time. For instance, one might defer a total building overhaul and instead replace an aging roof assembly with a more energy-efficient one.

Many grants and incentives are also available for school districts. Rebates are available for converting existing lighting systems to current standards or replacing older HVAC equipment with newer and more efficient equipment. The State of Texas, through the State Energy Conservation Office (SECO), has provided multiple grants to smaller districts to replace older lighting and HVAC systems and provide solar power. One of the larger electrical distributors in Texas has provided rebates for higher efficiency HVAC equipment, lighting, high efficiency roof, high efficiency window glazing, and other energy efficient building systems. Grand Prairie ISD is currently closing out their summer 2016 projects with the Oncor energy efficiency incentive program, and the utility company will compensate GPISD upon Oncor’s inspection of the energy saving measures incorporated into the design.

school construction of walls

PHOTO COURTESY OF CORGAN

Accurate and accessible as-built documents, product manuals and warranties allow for ease of troubleshooting and maintenance schedules. Recordkeeping software, such as the Project Documentation Software by Ex3 Facility Solutions, can pinpoint specific equipment types, controls and locations installed in each school, reducing time and road-blocks to properly maintain facilities.

In Conclusion

Energy efficient design can have a truly positive effect on our schools. In these times of increased financial scarcity and scrutiny, thoughtful approaches to energy saving can help direct resources back to personnel and students, creating a meaningful impact on students, schools, districts and communities.

This article originally appeared in the December 2016 issue of School Planning & Management.

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