Methodology to calculate the energy consumption for lighting in buildings

This paper proposes a methodology to benchmark lighting energy consumption for new building design or new lighting systems in existing buildings. The influences of electric lighting, daylighting and the lighting control system are evaluated for every building zone. This methodology uses the installed lighting power density, the area of the daylit and nondaylit sections and the effective operational times during daytime and night-time for each building zone. The calculations (based on the German standard DIN 18599 and the North-American standard ASHRAE-IESNA 90.1) allow a trade-off of the energy consumption between different technical areas such as lighting, heating and cooling. The energy consumption of these different technical areas can be compared enabling the user to monitor the influence of different choices (e.g. installing a different technical system). This methodology forms the basis for the lighting trade-off compliance path of the Canadian Model National Energy Code for Buildings (MNECB).