**4.1 The modular square form equipped by four Ventilated Double Light Pipes**

A certain number of VDLP can be installed in order to generate a modular architectural structure, by which more complex buildings of various geometrical forms may be obtained.

Fig. 10. Basic square modular form

In Boccia et al (2011), the authors proposed a two - level square basic modular form with four VDLP and presented the results of a numerical simulation, regarding daylight and natural ventilation performances. Each level consists of a 14x14 m2 plant area room, 4,5 m high, in which two inlet and two outlet devices are installed, with the intention of introducing daylight in both the intermediate and the final room. At the same time natural ventilation by the VDLP installed is achieved in the passage room. Figure 10 shows the square model equipped by four VDLP.
