Enhancing the learning experience in K-12 schools: Sustainability and energy efficiency
K-12 schools are among the most important projects engineers can tackle. Professionals focus on energy efficiency design advice for educational facilities.
Tony Cocea, PE, Principal, DLR Group, Los Angeles
Michael Do, CEM, CxA, AX TCP, Director of Engineering Sciences and Commissioning, Setty, Fairfax, Va.
James Dolan, PE, CEM, CPMP, LEED AP, Principal in Charge of Energy Engineering Services, OLA Consulting Engineers, Hawthorne, N.Y.
Mark Fisher, PE, LEED AP, Principal, AlfaTech Consulting Engineers, San Jose, Calif.
Douglas R. Hundley Jr., PE, CGD, LEED AP, CxA, Mechanical Engineer, CMTA Consulting Engineers, Louisville, Ky.
Peter McClive, PE, LEED AP, Senior Vice President, CannonDesign, Grand Island, N.Y.
CSE: Energy efficiency and sustainability are often a request from building owners. What net zero energy and/or high-performance systems have you recently specified on a K-12 building (either an existing building or new construction)?
Fisher: We have specified components of high-performance systems, but no net zero energy systems. Again, due to the way budgets are created, payback evaluations (or prepaying for future operational costs) that might warrant a net zero design are not possible.
Hundley: All of our five net zero K-12 buildings used ground-source heat pump systems. Our best-performing schools all use ground-source heat pump systems, ranging from a site energy-use index (EUI) of 18 to 26.
Dolan: A key for owners to reach net zero is to optimize the size of the HVAC systems as well as lighting and other loads in the building. Using energy analysis as well as engaging the load calculations and other tools to improve the envelope are necessary early steps. Insulation performance, tightness of building, type and amount of glazing, as well as proper orientation are all considerations. Ground-coupled heat pumps are good options because they can be efficient, avoid fossil fuels, and also enable the design team to start at an already lowered energy use. Heat recovery to address outside air/exhaust is critical; all systems, short of kitchen-grease exhaust, should be passed through the exchanger. Achieving some level of renewables is an important approach to consider on every project. If the overall system size is reduced significantly, the remaining energy use may be accounted for with solar PV or solar thermal energy.
CSE: Many aspects of sustainability (power, HVAC, maintenance, etc.) require building personnel to follow certain practices to be effective. What, if anything, can an engineer do to help increase chances of success in this area?
Cocea: The controls must be well-explained to all people involved, and the system software design should be user-friendly. The controls-monitoring program is a good tool to assure the systems perform as required.
Dolan: The engineer and/or operators can emphasize that commissioning should be part of every new building project and significant renovation. ASHRAE Guideline 0: The Commissioning Process and other standards stress training and help ensure that the commissioned systems perform in keeping with the specifications. Early collaboration with operators/facility management can often be emphasized as part of the commissioning process and is critical to the success of the project. The operators should also be included in the post-occupancy review of utility bills. As part of that analysis, feedback should be presented on comfort and other maintenance issues.
McClive: MEP systems represent significant continuing costs both in energy and the cost to maintain them. Renewable energy concepts must be simple systems that allow K-12 building staff to easily maintain and operate their facility.
Hundley: The main thing an engineer has to understand is how the building will be used. You may say that a K-12 school is pretty cut-and-dried, but that is not true. Schools are also used as community centers, as summer schools, and to host after-school programs. Understanding what areas will be used will help in designing a system that can be operated to minimize starting the entire school to accommodate the use of one area. This can be accomplished by writing special scheduling into the building automation system, or having separate systems.
CSE: Please share a K-12 success story in which you were able to enhance the sustainability of an existing building.
Hundley: We recently completed a renovation of an elementary school, constructed in the early 1990s, and the school was suffering from poor IAQ and energy usage. After the renovation, the energy consumption was reduced to an EUI of 24, and the IAQ issues were totally resolved. Due to the age of the building, we even reused the existing piping to help minimize construction costs.
Fisher: Recently, we replaced information technology systems districtwide for Morgan Hill Unified School District in San Jose, Calif. The district's Measure G Bond program consists of many different projects. One component includes separate electrical engineering, low-voltage systems, network/data systems planning, engineering, and design. This includes 15 sites: nine elementary schools, two middle schools, two high schools, one charter school, and a district office. Each project required separate investigations of the existing school campuses, systems, and capacities currently consisting of multiple permanent and portable classrooms, administrative areas, gymnasiums, science labs, libraries, multiuse buildings, and other specialty-use spaces.
CSE: Please describe your experience in smart or intelligent K-12 buildings.
Hundley: The combination of submetering and digital building controls makes it simple to implement demand-response schemes. Although our heat pump designs have far less electric demand, we often include control sequences to lower temperature setpoints as peak demand approaches a predetermined limit. K-12 buildings with high-performance envelopes often experience this peak demand early in the morning when kitchen equipment is in use and heat pump systems are performing building warm-up simultaneously. Staggering zone warm-up can help reduce this peak.
CSE: Have you worked with a K-12 building client to specify kiosks or other prominently displayed energy efficiency monitoring systems in a building? What types of tools are clients requesting to encourage their people to save energy?
Dolan: We have worked on a number of projects that used packaged software to display energy savings and encourage interaction with students and teachers. Often, the software and associated components require additional ongoing maintenance. Walking into a building a year later and seeing that kiosk not functioning is disappointing. We have taken the approach to truly design the BMS dashboard for projects, and in working with controls contractors. The resulting product is excellent, gives the key metrics to the end users, and is maintained as part of the regular operation of the building. This dashboard can be displayed in a lobby to achieve the same effect as a packaged system with a kiosk. Having an appropriate and maintainable feedback system will ensure long-term focus on the energy performance of the building.
Fisher: We have not specifically designed kiosks or displayed energy efficiency monitoring systems in a building. However, we find that clients typically use their BAS to save energy.
Hundley: We design energy dashboards for most of our zero energy K-12 projects. These are designed not only to inform occupants and guests about the building's features, but also to challenge them to operate the building more efficiently with real-time energy-usage feedback. These can often be very challenging to complete correctly. Our experience has been that (despite encouragement) this item is usually left to last, once the rest of the building is complete.