After the dimensions of the skylights and the constructive solar shading were found with Relux, a building model for the whole library was made in Relux, including all skylights with fins and all inventories in the library. In figure 5, the model is seen from northeast with the Children’s section facing south.

Figure 5\mpdel of the library made in Relux fir$fessional/Vision seen from northeast with skylights including all fins working as constructive solar shading.

The model was simulated with an overcast CIE sky. The long simulation time (6 days) due to all the fins in the skylights, limited the mesh that was set to 0.5 meters. After ended simulation it is possible to have a walk through the library and get a feeling of the daylight conditions. Thereby it is possible to optimize the indoor daylight conditions and place the permanent working spaces and inventory so the daylight is used where it is needed the most and avoid glare problems.

Figure 6, shows the simulated daylight conditions in lux for the whole library on an overcast CIE sky in a plane 0.85m above the floor. The lux level is 0 — 600 lux.

From figure 6, it can be seen that the daylight level is at a sufficient level, exceeding 200 lux (daylight factor = 2), in most of the library. Especially the public section of the library has a daylight level above 200 lux. It is also interesting to note, that the daylight level is higher between the skylights than right underneath them. The bookshelves are situated right between the skylights thus taking advantage of the high level of daylight there. The higher level of daylight between the skylights can also been seen in figure 7, where the actual daylight distribution on a sunny day is shown.

Figure 8 shows the simulated daylight distribution in the library seen from the west end of the library with the children’s section on the right on an overcast CIE sky expressed from 10 cd/m2 to 50 cd/m2.

In figure 9 and 10, the actual daylight conditions on a sunny day are shown for the almost finished library.

The traces of sun on the floor and facade from the skylights and due to the constructive solar shading, gives a finishing touch on the daylight distribution. The traces of sun also moves relative fast so the traces have moved from one side of each skylight to the other during a couple of hours. Furthermore, the number of hours the sun traces are appearing each day is highest during summer and goes to zero during wintertime.

1.2 Conclusion

From detailed simulations carried out for the library, constructive solar shading in the skylights has been developed. The constructive solar shading has a depth of 200 mm and is placed every 500 mm in each side of each skylight. The constructive solar shading contributes to an optimized daylight distribution inside the library and at the same time decreases the level of solar radiation into the library thus increasing the level of thermal and visual comfort.

Furthermore, the level of daylight and daylight distribution has been optimized with simulations. After construction the level and distribution of daylight met our expectations. Glare problems has been avoided by the constructive solar shading in the skylights, a solar curtain in the children’s section and by using the daylight simulations to optimize the inventory plan.