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SUNFLOWERS PROJECT

The project is realised in collaboration with the Consorzio CEO-Centro di Eccellenza Optronica and the Museo Stibbert of Florence and it foresees the illumination of several showcases located in the Islamic Room by means of a system for solar light collection and optical fibres.

"I Girasoli" (The Sunflowers)

Each Sunflower ("Girasole") includes solar collectors, optical fibres and mechanic and electronic systems for sun tracking.  The light focused by the solar collector has two possible uses: 1) direct illumination of showcases, 2) accumulation for lighting during sun absence. -  The first function is obtained coupling the optical collector to the optical fibre, which transports the solar light into selected lighting points within showcases. - The second consists in focusing the solar light on a photovoltaic cell (PV), last generation type, with high efficiency (30%, not achievable by current PV collectors).  In this way the PV cell converts the focused light into electric energy to be used for illumination in case of sun absence.   These two functions are selected by a "visitor presence detector" located in the museum room.

The Islamic Room

The next figures show the Islamic Room of the Museo Stibbert and the showcases with the solar illumination realised by the Sumflowers placed on the room roof.

The first figure present the layout of the Islamic Room, with the showcase disposition.  Showcases 1 and 2 (Vetrina 1; Vetrina 2) have a lenght L=5m and a Height H=3m, while The Showcase 3 (Vetrina 3) has dimensions L=2m x H=3m.

The pictures report the showcases before and after the installation of the illumination plant using optical fibres connected to 5 Sunflowers on the roof. Each Sunflower includes 8 solar collectors, coupled to 8 fibre bundles, each of which has 7 fibre terminations. These optical fibres transport the light, concentrated by the solar collectors, within the showcases realising the lighting points. The application in museum lighting ,and in particular to illuminate almost metallic weapons, has required a further study on the light colour, which has been filtered toward warmer tonalities.

Showcase 1

Showcase 2

Showcase 3

Solar collectors

Aspherical lenses, especially designed to be realised in PMMA (plastic), have been used as solar collectors. Further details on the solar collectors can be found in the page collectors.

Aspherical Lens in PMMA

Mechanics

Figures present the two types of Sunflower: the taller one (h=160cm) is used to form the flower bed in the garden, while the shorter one (h=80cm) is used in the installation on the roof of the Islamic Room.

The mechanics, driven by the electronics, realises the sun tracking orienting the flower of the Sunflower, mounting 8 solar collectors, always in direction of the sun rays.

The "Girasoli" solar plant

The Sunflowers ("I Girasoli") have been installed at the Museo Stibbert, in two different locations:

1) the 5 Sunflowers on the roof of the Islamic Room provide the lighting of the room showcases;

2) a flower bed composed of 4 Sunflowes placed on the terrace (on the left of the museum entrance staircase).

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