عنوان مقاله [English]
Building design including energy saving features and natural resources protection, is one of the main responsibilities of architects. Atrium is an open interior space that can be potentially related to the exterior environment and in addition to its impact on energy optimization, it can have positive effect on the occupants’ indoor environmental perceptions. In this study two case studies of office buildings (with and without atrium) in Tehran were selected. These buildings had minimum differences in terms of number of floors, the ratio of the area of exterior openings to wall area, heating and cooling systems, average number of staff per square meter, construction materials and insulation properties. The aim of this study was to investigate and compare the quality of indoor environmental conditions and energy consumption in the both office buildings, with central atrium and without atrium to optimize energy consumption and workplace conditions. In this research, field experiments, including questionnaires and physical measurements of environmental parameters simultaneously were used. The field experiments (data logger and questionnaire) were conducted during the summer in the both buildings. The Field studies were carried out by environmental measurement methods through research tools including thermometers and lux meters. The measured variables are temperature, relative humidity and lighting intensity. To measure the temperature and humidity simultaneously, the Standard Thermometer with an accuracy of ± 0.1 ° C is used and a Standard st-1309 lux meter is used to measure the light intensity. Data loggers are positioned away from the direct effects of energy sources such as solar radiation, cooling systems, and etc. The device is placed in the workplace near the staff table. The field measurements were carried out on July 2013, for three working days. For measuring lighting data, the amount of daylighting in all directions and in all floors was recorded by lux meter device in the both studied buildings at 8-10 am and 12-14 pm. To develop the questionnaire, the format of the international standard questionnaire of ASHRE Standard 55 (2013) and the Center for the Built Environment (CBE) in the University of California-Berkeley were used. Then to adapt the questionnaire with the research hypotheses, changes were made to the questions and also new questions were added to the text of the questionnaire. In the format of the questionnaire, the main questions are divided into various categories such as personal and background questions, satisfaction questions and questions related to the quality of the indoor environment. For data analysis, Principal Component Analysis (PCA), independent t-test, Mann-Whitney test, univariate analysis, variance analysis, the Spearman correlation analysis and Duncan’s multiple range test were used. The results of the questionnaire response show that there was a significant difference between the votes of the staffs in the two studied offices (with and without atrium), including; the satisfaction of the cooling and heating conditions of the workplace, the thermal conditions of the working environment in the summer and winter, the temperature conditions in the very hot / Warm air/ cold weather conditions, the reason for perceived thermal discomfort in the summer, the need to turn on the lamps during different days of the year, the required amount to turn on the lamp in cloudy days, the satisfaction with natural light in the workspace, the satisfaction degree with visual comfort in terms of glare and contrast. The results showed that there was a significant positive effect of atrium on staffs’ satisfaction regarding the indoor environment conditions of thermal comfort, lighting quality and visual comfort. The data show that the indoor air temperature of the Ministry of Health (without atrium) is on average 25 ° C and warmer than the railway building (with atrium). There is also a small difference in comparison between measured relative humidity data between the two buildings. The comparison of the results based on the Duncan test showed that the southern direction received the highest amount of day lighting while the north and west directions had the lowest amount similarly in the both studied office buildings. Furthermore, the results showed that the amount of day lighting was higher in the building with atrium compared to the building without atrium, while electrical energy consumption, relative humidity and temperature was lower in the building with atrium. In general, the result showed that atrium had a significant effect in reducing energy consumption and providing thermal comfort in this office building. In order to generalize the results of the research, it is necessary to conduct such research in a large number of similar study samples.