Document Type : Original Article
Authors
1
M.A. in Interior Design, University of Arts
2
Assistant Prof., University of Arts
Abstract
Of the total electrical energy consumed in Iran, 70% is allocated to lighting interior spaces of dwellings. Then a simple method to conserve electricity is using daylight for illumination, which mainly depends on window specifications and depth of room. It should be remembered that interior design of a room can also affect the amount of electrical energy consumed for illuminating interior spaces. Researches carried out so far on day lighting mainly concentrate on the dimensions and specifications of the openings. In this paper, the authors have studied the effect of the interior design in a bedroom in Kermanshah, including variations in furniture arrangements, materials of interior surfaces and their colours, and also window position on interior illuminance. This research is based upon the simulation. For this purpose, the Dialux software has been used, whose validity is studied in related researches, which show that the simulated quantities are very similar to that of the real ones. In this software, there are three different skies: sunny, semi-cloudy, and cloudy. For this simulation, sunny sky was chosen for Kermanshah. The calculated items of this research are as follows: the intensity of average, minimum, and maximum illumination of the room under study and the same amounts for the illumination of floor, ceiling, and walls for each month of the year with five days intervals, totaling 72 days, at 10:30. Concerning day lighting, 10:30 is a time when there is enough sky illuminance during the year in Kermanshah. The illuminance intensity on remaining days of the year is almost similar to the selected ones, and as a result, the simulation has not been carried out for the whole year. Additionally the same amounts of illuminance for solar equinoxes and solstices, from sunrise to sunset have been simulated. Four different materials for the floor have been applied. The number of chosen materials for the walls was six, and two for the ceiling. Different arrangements have been designed for the room under study. Actually the components of the furniture has been omitted one by one to show the effect of each one on the interior illuminance. Eight different colours – from light (yellow) to dark (brown) – have been compared for the interior surfaces, regarding the interior illuminance. Moreover, variations in the height of the ceiling and window sill have been studied. It has been found out that not only the colour of interior surfaces, but also the interior design of the room can change the amount of natural light inside. Decrease in ceiling height and increase in widow sill helped to increase the average illuminance of the room. It has been observed that the best position for window, in order to distribute light more uniform within the room, is in the center of the wall. The results showed that to increase the interior illuminance, walls, ceiling and floor should have materials with light colours and high reflectance factor. On the other hand, the arrangement of furniture must not obscure the light from windows. Less furniture around the windows and inside the room increases the amount of daylight entering the room significantly.
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