A new adjustable and extensible lamella device for permanent external solar shading systems

A new mechanical device has been designed in order to improve the seasonal flexibility of permanent external shading systems based on lamellas. In fact the new device allows for varying both the tilt angle and the lamella extension. The performances of lamella systems equipped with such a device was evaluated in combination with different glazing systems and compared to adjustable but not extensible systems. Beam and diffuse solar and light transmittances were calculated for different solar positions and the effective monthly averaged solar factor was derived for different sites. The results show that the system with the new lamella device has the same capability to shade beam radiation while at the same time allowing for significantly higher penetration of diffuse radiation. This results in a higher potential for the exploitation of daylight and solar gains.