Designing efficient K-12 schools: Electrical, lighting, power
In a digital age, children across the U.S. are more technologically advanced than ever—and they require educational facilities that can keep up. Here, engineers with experience working on K-12 schools share views on what’s trending with electrical/lighting/power in these facilities.
Maxwell Chien, PE, LEED AP BD+C, Associate, Kohler Ronan, New York City
Chuck Dale-Derks, PE, LEED AP, Principal, McClure Engineering, St. Louis
Evan J. Hammersmith, PE, LEED AP BD+C, CGD, Associate, Mechanical, Karpinski Engineering, Cleveland
Michael Lentz, PE, CPD, HFDP, Director of Operations, Baltimore Office, Setty, Baltimore
Rodney Oathout, PE, LEED AP, CEM, Principal | Energy + Engineering Leader, DLR Group, Overland Park, Kan.
Michael Rader, PE, CEM, Vice President and Chief Operating Officer, Barton Associates Inc., York, Pa.
CSE: Studies show daylighting makes a difference in students’ ability to learn and retain information. What new lighting and daylighting techniques are designers using in these schools?
Rader: The lighting levels and lighting controls should be designed to address the addition of daylighting the classroom. Electric lights in daylighting zones should have the capability of dimming/switching separately from the other general lighting in the space. Also, motorized window shades have become an important addition in many classroom spaces. Lighting designers have begun providing lighting control systems that integrate the shading controls into the programmed preset lighting scenes.
CSE: Describe metering or submetering in a K-12 school building. What did it include, and what best practices did you include?
Chien: We designed a net zero environmental center that is considered a living/learning space that includes dormitory, labs, classrooms and dining facilities. Electrical consumption was metered at each branch circuit, which allowed in-depth analysis by the building occupants.
Oathout: It’s standard practice to provide at least one meter at the incoming electrical service on our K-12 projects. We use this meter to drive electrical peak-demand avoidance strategies. We recognize that K-12 facilities have repeatable electrical peak-demand profiles. By monitoring the power consumption, we have developed nearly undetectable strategies for avoiding the peaks in power consumption (sometimes called electric demand). Lowering the electric demand of a facility will have a direct impact on the electric bill under most utility tariffs in the United States.
CSE: How have lighting and lighting control systems been integrated with other systems in such structures (i.e., the HVAC system)?
Chien: We have seen a lot of lighting control integration with AV/IT equipment at the teacher’s desk, along with motorized shades control. All of this controllability is located at the teaching lectern or desk. The need for daylighting, while also providing the correct light levels for projection, has made teacher control of motorized shades essential.
Rader: Often, lighting control systems are tied via a central protocol (such as BACnet) to a centralized building management system (BMS). The BMS operates both the lighting and HVAC based on time clock settings, input from occupancy sensors, or a combination of the two. In smaller buildings without a BMS, HVAC controls can be tied directly to the occupancy sensors provided as part of lighting control systems via dry contacts. This will allow the HVAC system to monitor occupancy without needing a separate occupancy device.
CSE: Describe a lighting control or addressable lighting project you’ve completed in one of these projects. What were the challenges and solutions?
Rader: In projects where the lighting control system is tied to a BMS, the biggest challenge is the potential lack of communication and collaboration amongst the disciplines during design and construction, which eventually translates to communication problems between the installed systems. The best solution for this is to have multiple meetings during design and construction where the design team, the owner, and eventually the contractors are present. This will allow all parties to communicate and understand the goals of everyone involved.
CSE: How have the changes in LED technologies and specifications impacted the design of projects for K-12 schools?
Oathout: Lighting solutions with LED technology are now the norm in K-12 building design. These fixtures not only provide substantially better energy performance and life expectancy, but they also offer more elegant solutions for varying light levels required by recent building codes.
Rader: The evolution of LEDs is ongoing, and their benefits continue to impress. For K-12 schools, LEDs have provided economical smooth dimming (100% to 1%) in classrooms in lieu of the traditional two lamp/one lamp of the past. LEDs have provided both “instant-on” and dimming for gymnasiums, which was not possible with high-intensity discharge (HID) lamp sources. In recent years, the introduction of “tunable white” (aka dynamic white) LED lighting has been a hot topic of debate and study when it comes to classrooms. Some studies have shown that students perform better on tests when tested under cooler white color temperatures (4,000K and above) and calm down faster under warm white color temperatures (2,700K).
Hammersmith: In addition to energy savings and long product lives, LED technologies have made it possible to specify lighting control systems that use daylight harvesting, dimming, and zone control without adding excessive costs. The added controls make it possible to create more dynamic educational spaces. With multiple zones in a classroom, for example, educators can dim the lights at the front of the classroom for viewing media while keeping the rest of the room comfortably illuminated. They can also provide students the flexibility to control lighting in collaboration spaces. LED luminaires are now available with tunable white lighting and control functionality. This technology gives educators the opportunity to change the color temperature and light level to facilitate student productivity, mood, and concentration.