On site assessment of energy conservation systems in high school lighting

Muriel Dupret, Pierre Fristot, and Olivier Sidler, ENERTECH, France
Philippe Gondolo, ARENE, France

Keywords

energy conservation, lighting, high school, monitoring campaign, end-use metering, data logger, electronic ballast, dimming, natural light

Abstract

Lighting systems were assessed in detail in eight high schools of the PACA region (south France). Funded by ADEME, ARENE, EDF and Region, the monitoring campaign covered the academic year 2000–2001.

Dedicated data loggers were designed to monitor lights energy consumption along with room occupancy and light levels. The small sized and autonomous devices worked successfully in the occupied buildings during extended periods.

More than 100 sensors allowed for precise evaluation of lighting time of use in different types of rooms as a function of the control strategy (switch, timer, IR sensor or using programmable automates).

The measurements show larger time of use in corridors and washrooms. It reaches around 1500 hours when controlled by a switch. Timers and occupancy sensors can cut energy cost by 2 or 3 provided that they are properly set and not forced on by cleaning staff.

Incandescent bulbs are still widely used. They are the best candidates for immediate replacement by CFL with shorter pay back times than control systems.

Classrooms have lower usage, typically below 1000 hours per year. The users seldom forget the lights on while leaving their room. Potential energy savings arise from improving the lighting systems. Electronic ballast, high efficiency tubes or reflectors make power drop but require large investments. They can presently only be justified in new buildings.

Dimming ballast with constant lumen controls were tested. Large savings require sensitive cells. Initial light levels and position toward windows have a large impact on system efficacy. Circuit separation for lights near windows or improved building design can also take profit of natural lighting at lower expense.