Development and experimental validation of a new model for integrated lighting design in industrial buildings

Natural lighting in industrial, commercial and sports buildings is usually provided by roofs with transparent surfaces. Sawtooth roofs, in which opaque modular elements are combined with transparent surfaces, whether inclined or in various shapes, are especially popular. The exact dimensioning of these roofs is extremely important both in terms of energy saving (less electricity needed for artificial lighting) and of vision quality. Artificial sources provide for an adequate level of illuminance on the work plane, integrating the function of sawtooth systems when external solar radiation is lacking. The paper illustrates a calculation method that accurately assesses lighting performances of industrial buildings with sawtooth roofs, in terms of both daylighting and electrical lighting. The method allows detailed modeling of the shape of the sawtooth roof to be created and of the materials making up the roofs, as well as the characteristics and positioning of the artificial sources. Experimental verifications were performed on the method in two industrial buildings, with different roofs; the results show that the calculation method being proposed is both accurate and reliable.