جستجوی مقالات مرتبط با کلیدواژه « روشنایی طبیعی » در نشریات گروه « هنر و معماری »

The accurate prediction of the visual comfort zone in an indoor environment is difficult as it depends on so many parameters such as individual and environmental variables. It is important in large compact urban areas in which the density and shadow from neighboring buildings can limit the accessible daylighting in indoor spaces. Lighting is one of the most important environmental parameters in office spaces. The employees spend most of their hours in office spaces during the day, and most of their activities are based on receiving visual information from the surroundings. Besides, being satisfied with lighting conditions is one of the main elements that significantly affects the environment’s overall comfort level. Currently, in Iran, the visual comfort zone and the preferred illumination level are not defined for office spaces, and experts refer to the findings achieved in other countries. To assess the lighting in architectural spaces and define the conditions for conformity in many standards, the authors have used some metrics as the physical measures. Generally, there are static and dynamic metrics to evaluate various aspects of daylight. Static metrics, such as illuminance-based daylighting metrics and Daylight Factor (DF), are typically evaluated based on illuminance and have been used in building regulations for a long time. In most standards and codes, the minimum recommended illumination level for working planes in a regular office is 500 lx. Due to climatic and cultural differences, the findings of other countries may not be appropriate for Iran. On the other hand, many studies have been conducted to find an acceptable lighting level in offices; however, the results show the acceptable range for illuminance in different countries is not the same. So, this paper tries to investigate the satisfaction range with the illumination level in office spaces which architects and researchers could use. Therefore, a field measurement was conducted to evaluate the illumination levels, and to examine the effect of lighting conditions on employee level of satisfaction and perception of lighting level with actual illuminance levels in office spaces in Tehran, using both questionnaire and physical illuminance measurements.

The focus is on six office buildings in the metropolis of Tehran, Iran. The buildings were selected to consider different spaces in old and new buildings, one-story and high-rise buildings, open plan, and cubicle offices with varying orientations. The selected rooms were one, two- or multi-user offices, located on different floors, with various window orientations and an optional atrium/outside window. Fluorescent interior artificial lighting was used in all spaces with a color temperature between 4000K and 5000K. The survey involved 509 questionnaires (280 were filled out in summer and 229 in winter).

Most of the participants have spent at least three months in their offices and have been adapted to the environment. All participants were Iranians (to avoid the impact of occupants’ culture on lighting perception). Most of them reported that they spend more than 8 hours or between 6 to 8 hours in their offices during the day. Field measurement includes illuminance, temperature, and relative humidity. The questionnaires were filled out in 146 and 109 rooms in summer and winter, respectively. At the same time, while users completed the questionnaire, the physical parameters were measured. The Spearman rank correlation coefficient was applied for quantitative variables. By using a monotonic function, the Spearman rank correlation coefficient is a non-parametric measure that assesses statistical dependence between two variables to describe their relationship.

The results revealed that occupants were more satisfied with higher levels of illuminance. The measured illuminance is categorized into certain levels to investigate the acceptable range for the lighting level. For this purpose, the measured lighting level was classified into 14 ranges. The values of less than 300 lx are in the first category, higher than 900 lx are in the last category, and the values between these mentioned ranges are classified into 50 lx intervals. The highest satisfaction from the environmental lighting level is provided in the illuminance range between 600 to 649 lx. The illumination level above this range results in more satisfaction compared to illumination levels less than 550 lx. Thus, there is an optimal range of satisfaction with lighting level, and the preferred lighting comfort range for the investigated office spaces is between 600 to 649 lx. While the illumination level higher than 550 lx is acceptable for most of the occupants.

Optimizing energy consumption in buildings, which includes a large part of the total energy consumed in the country, is very important. The window is also part of the interface inside and outside the building. The purpose of this research is to optimize the opening in the office in Tehran in terms of obtaining enough daylight and reducing energy consumption.

Simulation and optimization of the window performed parametrically in the Grasshopper and analysis of the objectives using the Honeybee and Ladybug plugins. The spatial Daylight Autonomy (sDA) and the Energy Use Intensity (EUI) calculated for proportions and varied window positions in eight variable directions.

The windows on the eastern north rotation and later in the east rotation had the best results. The window to wall ratio was 20% to 28%, with an average length of 6.53 and 0.9 meters, respectively, for the research model, the most ideal response. The distance between the windows to wal and the sillheight were respectively 0.65 and 2.22 meters.

Using modern simulation techniques enables building designers to have more intelligent choices in design with scientific approaches. The repeatable framework presented in this study can be used for buildings with different user positions or proportions, and ultimately enable designers to play an effective role in sustainable development by increasing their design productivity.

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.