Budget-Conscious Ways Schools Can Use Emerging Green Technologies to Reduce Energy Costs

Whether constructing a new building or renovating an existing building, school systems across the country are looking for ways to reduce energy costs. Three emerging green strategies are worth investigating for long-term budget savings: efficient lighting, chilled beams, and displacement ventilation.  
Lighting efficiency is currently one of the best methods for reducing operating costs. Electric lighting can typically account for 30 percent to 40 percent of all commercial and school building electrical use. Lighting experts have made significant advances in the past decade resulting in lighting fixtures and technologies that can reduce these costs by more than 50 percent.

Today’s pendant and recessed fixtures — widely available through leading manufacturers like Finelite and Ledalite — can achieve a lighting power density of 0.5 watts per square foot, which represents nearly a 60 percent reduction in energy use compared to the base code for classrooms. 

Incorporating efficient fixtures into your building is no more expensive than installing traditional fixtures. Although the fixtures do cost more per unit because of their power and high efficiency, fewer fixtures are needed. Reducing the fixtures in a classroom also has the added benefit of cutting costs from air-conditioning bills since the fixtures produce less heat in the room. Schools can benefit from additional cost savings by combining daylight harvesting and occupancy sensors into its efficient lighting plan. 

Because efficient light fixtures produce less heat than traditional fixtures, schools have more choices when it comes to selecting air-conditioning and HVAC systems. Specifically, schools can consider chilled beam and displacement ventilation systems, both of which contribute to significant energy cost savings. 

Chilled beam technology utilizes air pressure to induce the flow of room air through coils that regulate a room’s temperature. The system only supplies required fresh air, thereby reducing the need for large ductwork through the building. The reduction of the air volume also translates into smaller motors to move the air. The 100 percent outside air unit also includes an efficient-energy recovery wheel that captures 60 percent of the embedded energy of the exhaust air, which can further reduce energy consumption. 

Another way to create long-term savings is to introduce a displacement ventilation system into the school’s design. Unlike conventional systems that need to cool the entire room to the same temperature, a displacement system cools half of the room, which reduces energy costs. Although cooling only half a room may seem counterintuitive, the displacement system creates a comfortable temperature for its occupants.  

Displacement ventilation systems introduce conditioned air near the floor and exhaust at the ceiling, and this supply air slowly displaces the room air, hence the name. The system can operate in dehumidification mode while maintaining the room in the comfort zone for the occupants, and the system can be designed to essentially cool only the zone between the floor and 78 inches, where most occupants are, which reduces energy waste and costs.

Although all three green strategies offer schools the chance to create energy savings, not all strategies can be implemented in every building. Both chilled beam technology and displacement ventilation systems have space constraints. For example, chilled beam technology is not the best choice for double-height spaces since it cannot efficiency cool the large volume of space. Chilled beam technology typically requires bigger units that take up more space than traditional HVAC systems because the system relies on a higher temperature to chill its water. So it may not be the best choice in highly constrained settings. 

While some of these technologies require higher startup costs, each technology yields a long-term benefit to the bottom line. Incorporating these three green strategies into your building can create long-term savings that keep your school budget on track and your school building environmentally friendly. 

 

Chin Lin, AIA, LEED AP, is director of green resources for HMFH Architects Inc. in Cambridge, Mass., an architectural firm focused on building opportunities for learning.