SOCIEDAD ESTATAL DE CORREOS Y TELEGRAFOS, S.A.E
Barcelona-Zona Franca Reforma nave A2 Parc Logístic-Zona Franca
Atres80 – Joan Escanelles
Study and developement of daylight autonomy – Benefit on the energy consumption and light quality
The daylight autonomy at a point of interest in a building is defined as the fraction of the occupied times per year, when the required minimum illuminance level at the point can be maintained by daylight alone. In contrast to the more commonly used daylight factor, the daylight autonomy considers all sky conditions throughout the year. It can nowadays be reliably simulated using dynamic daylight simulation methods. Example A daylight autonomy of 70% for a work place with working hours on weekdays between 7 a.m. and 6 p.m. and a minimum illuminance levels of 500 lux informs that the occupant can potentially work 70% of the year by daylight alone. In the Correos Building the daylight autonomy is apparently low because the working hours are 24/7 and also night hours have been calculated
Lux- average 661 – h 12:00 -December 21th – Cloudy sky
Lux- average 327- h 9:00- December 21th – Cloudy sky
Lux- average 435- h 16:00- December 21th – Cloudy sky
Daylight Factor (DF) Analysis: 95% of all illuminance sensors have a daylight factor of 2% or higher.
Electric Lighting Use: The predicted annual electric lighting energy use in the investigated lighting zone is: 135.0 kWh/unit area.
Site Description: The investigated building is located in Barcelona (41.30 N/ 2.10 E). Daylight savings time lasts from April 1st to October 31st.
User Description: The zone is continuously occupied Monday through Friday from 0:00 to 24:00. The total annual hours of occupancy at the work place are 6002.0. The electric lighting is activated 6106.0 hours per year. The occupant performs a task that requires a minimum illuminance level of 500 lux.
The predicted annual electric lighting energy use of 135.0 kWh/unit area is based on a user who keeps the electric lighting on throughout the working day, and keeps the blinds lowered throughout the year to avoid direct sunlight. Lighting and Blind Control: The electric lighting system has an installed lighting power density of 22.00 W/unit area and is manually controlled with an on/off switch. The office has no dynamic shading device system installed.