Assessment of fixed shading devices with integrated PV for efficient energy use

The use of external fixed shading devices to adjust solar influx radiation and to save energy is well known. However, fixed shading devices can reduce daylight availability, increase artificial light needs and block the beneficial winter solar radiation. This paper is part of a research on the characteristics of the optimum shading device. The aim is to investigate the balance between the energy needs for heating and cooling the space that the shading device is used for and the energy that is used for lighting the same space and the energy that the shading device can produce. In order to investigate the balance between the above mentioned parameters, thirteen types of fixed shading devices have been studied and categorized according to their energy performance, for a single occupant office room. The same office room is tested for two different Mediterranean latitudes in Athens and in Chania, Crete in Greece and for two different south facing windows' sizes. The thermal behavior of the devices is assessed through computer simulation application and the daylight analysis is assessed with both computer simulation and physical modeling. Stable parameters were the internal loads in the office room, the south orientation of the facade and the type of glazing. Variable parameter was the type of the fixed shading device. The study shows that all shading devices with integrated south facing PV can efficiently produce electricity which may be used for lighting. The study highlights the fact that shading devices such as Surrounding shading, Brise-Soleil full facade and Canopy inclined double work efficiently against thermal and cooling loads and may be used to produce sufficient electricity and control daylight. The study defines the geometrical parameters that will be incorporated to the overall characteristics of the optimum fixed shading device and proposes new fields of development for the BIPV technologies. (C) 2012 Elsevier Ltd. All rights reserved.