A detailed, accurate study of openings has been conducted. The building’s orientation, with long east and west walls, is not the best for providing the most pleasant views or optimal comfort, due to overheating. To offset this, spaces have been redirected so as to face south, forming the saw-tooth pattern, which closes off the north and west of the building, opening all the spaces to the south. This gives the best orientations from the climatic standpoint and affords the most open views. Using this system, 89% of the surface of the spaces face south and east. (Figure 1).
This saw-tooth or zigzag, together with the brise soleils that protect all the openings, give a self-shading effect which reduces cooling load without restricting natural light (Figure 2). According to the simulations performed, and comparing simulated buildings 1 and 3, as well as 2 and 4, the self-shading effect in the design is seen to yield a 27% reduction in cooling requirements in a building which strictly complies with Spanish Building Regulations (CTE). Together with other lighting strategies, in the LUCIA building this leads to a 29.6% saving in cooling energy requirements, allowing direct differences to be established between one “straight facade building” and one with an “saw-tooth facade”. There is a 54% (Graph 1) saving thanks to the self-shading effect. In addition to offering significant improvements in user wellbeing, the zigzag solution provides clear thermal and financial advantages. One key factor to be taken into account regarding Spain is the importance of providing cooling during several months of the year.
The annual 146,190 kWh lighting that would be needed by the reference building (ASHRAE standards) would be cut to 74,790 kWh in the LUCIA building (approximately half) thanks to these devices (Figure 3). A total of 27 devices have been installed at a cost of 13,483 €. One key point is that these devices function purely on an optical effect and require no power supply to work.