When education institutions are spending about one-third of their maintenance and operations budget on gas and electricity, it's no wonder that administrators and facilities managers are seeking solutions to maximize energy efficiency. Moreover, their efforts are part of a broader sustainable-design movement that is being embraced by institutions, architects and engineers, and supported by state and local initiatives. For example, California school bond measures provide additional funds for school construction projects that exceed California's Title 24 energy-efficiency standards through sustainable design.
Factors with a significant influence on sustainability, including site selection, building location and site orientation often are difficult for schools to control. However, three fundamental design strategies are feasible for virtually any new school construction project: an integrated lighting system that maximizes natural light; reduction of the building envelope through consolidation; and consolidation of the mechanical system as a ground-level central plant.
- Integrated lighting
Integration of natural and artificial lighting creates a high-quality education environment while saving energy. To be effective, it must be an automated system that enhances the teaching environment and is easy to use. An effective system incorporates louvered skylights and windows with light sensors that automatically control the amount of light entering the classroom and raise the level of supplemental artificial lighting as necessary to achieve the optimal illumination level. A good system also incorporates a user-friendly electronic control panel near the markerboard or teacher's workstation that allows a teacher to override the automatic controls, adjusting lighting by choosing from preset teaching modes — for example, lecture using the markerboard or chalkboard, desk-to-desk interaction or projection.
- Reduction of the building envelope
The building envelope is a major source of heat gain and loss, depending on the season, and contributes to fuel and electricity consumption. Consolidating separate buildings into one or massing individual buildings appropriately to reduce the area of the building envelope enhances energy efficiency. At the same time, this strategy reduces the building footprint and increases outdoor play and gathering spaces. By reducing impermeable surface area, a school can better control stormwater runoff and the associated cost of stormwater management. It also is key to the third fundamental strategy: integrated building systems.
- Integrated building systems
Appropriate campus consolidation and building massing creates the ideal condition for use of an integrated mechanical system. This strategy uses an energy-efficient, ground-level central plant piped to school campus buildings' air-handling units rather than the less efficient rooftop package units that typically are found on standalone buildings. At the same time, this strategy removes the structural load of rooftop equipment, curtailing construction costs, for example, by reducing the quantity of structural steel.
Adding a pretreatment component to the central plant enhances energy efficiency further. Pretreatment component elements use a heat-exchange system to pre-warm winter air using the heat from exhaust air, warming fresh air by 5 to 6 degrees before it is heated by the furnace. In the cooling season, an evaporative cooling element pretreats fresh air by 5 to 6 degrees before it is cooled by the chiller. Pretreatment enables reduction in the overall size of the central plant and reduces operating costs. Ideally, this strategy should be developed through a team approach by the architect; mechanical, electrical and structural engineers; contractor; and school maintenance team.