Journal of Iranian Architecture & Urbanism(JIAU)

A comparative study of the kinetic movement pattern of a triangular geometric facade regarding natural lighting in an office building in Tehran

Fataneh Sangtarash; Niloufar Nikghadam; Rima Fayaz; Mohammad Reza Matini

Volume 14, Issue 2 , December 2023, , Pages 159-175

https://doi.org/10.30475/isau.2023.360937.1976

Abstract

Extended Abstract Background and Objectives: Since the reception of natural lighting in different places is different regarding the sun path and the different sky conditions during ... Read More Extended Abstract Background and Objectives: Since the reception of natural lighting in different places is different regarding the sun path and the different sky conditions during the day, season, and year, employing a kinetic facade allows for the adjustment and enhancement of interior natural lighting levels. The geometric pattern and the movement pattern are critical issues in the design of kinetic facades. One of the strategies use in this facade is the control of light entering the space. Another advantage of their efficacy in enhancing the quality of daylight is the improvement in visual quality, particularly in office and public areas. Hence, this present study explores natural lighting by employing two kinetic facades. These facades feature a comparable triangular geometric model but differ in their non-symmetrical folding and rotating kinetic design on the south wall of an office building in Tehran. Consequently, the dissimilarities in kinetic models are compared based on the utilization of natural lighting, and their similarities are identified and analyzed to determine the most suitable option.Methods: To assess natural lighting, the quantitative method and simulation tools utilized were Grasshopper and Honeybee Plus plugin version 06, along with Ladybug lbt version 1.5.0. Subsequently, the simulation results were scrutinized employing the comparative study method. Initially, the simulation involves defining the geometry of a room with specific dimensions: a width of 4 meters, a length of 6 meters, and a height of 3 meters, resulting in a total area of 24 square meters, intended for four employees. The simulated model is located in Tehran, with no shading obstacles. The facades will open and close with the position of the sun and the perpendicular vector on the triangular geometric model. The simulation is run for three days of the year: the 21st of March (spring equinox), the 21st of June (summer solstice), and the 21st of December (winter solstice) (due to the similarity of the autumn equinox with the spring equinox, the latter is not considered) and working hour is from 8 a.m. to 4 p.m.Findings: When comparing the facades, it is observed that the folding kinetic model presents a potential issue of glare and visual discomfort in the space during the months of June, March, and April. This concern is particularly notable at 12 noon in both June and March, coinciding with low light conditions in the space. However, the facade with a rotating kinetic model is only faced with the issue of insufficient light in the space. In order to address these issues, various parameters have been modified. To enhance UDI (Useful Daylight Illuminance) indices with a rotational kinetic model, adjustments were made to ASE (Annual Sunlight Exposure), sDA (Spatial Daylight Autonomy), and UDI indicators with a folding motion model. Variable parameters included alterations in facade size, modifications to the visual transmission coefficient of glass, adjustments to the reflection coefficient of interior walls (ceiling and wall), and changes in the angle or degree of openness for these indicators.Conclusion: In conclusion, it can be said that a kinetic facade with a triangular geometric pattern and asynchronous motion patterns exhibit different performances in response to natural lighting, considering daylight performance indicators. The facade with a rotating pattern demonstrates a notable impact on the UDI (Useful Daylight Illuminance) daylight indicator, and this effect can be mitigated by adjusting the angle. However, in the kinetic facade, the fluctuation of ASE (Annual Sunlight Exposure) and UDI (Useful Daylight Illuminance) indicators is less influenced. This is attributed not only to the shifting position of the sun in relation to the facade but also to the simultaneous necessity of altering both the extent of the facade opening and the reflection coefficient of the window and glass. The response of both facades, influenced by the variable parameters, places greater emphasis on the degree of facade opening and its correlation with the sun’s position, rather than on the reflection coefficient of the surfaces and the visual transmission coefficient of the glass. Finally, the rotational motion pattern performs better in response to natural lighting.

Identification and assessment of the effect of environmental, personal and social components on thermal comfort in office buildings

Bahareh Bannazadeh; Shahin Heidari; Habib Hadinafard

Volume 13, Issue 1 , May 2022, , Pages 259-279

https://doi.org/10.30475/isau.2021.222582.1371

Abstract

Extended AbstractBackground and Objectives: Thermal comfort is one of the comfort aspects in current architectural design and can be changed by various components. Researchers emphasize ... Read More Extended AbstractBackground and Objectives: Thermal comfort is one of the comfort aspects in current architectural design and can be changed by various components. Researchers emphasize that early thermal comfort studies relying on climate and environmental aspects can only justify a part of the results. Therefore, it is necessary to examine the effect of other components. Effective components could be found in physical, physiological, psychological, social, environmental, and economic aspects. So, thermal comfort can be influenced by inner and outer factors. Regarding the research literature and the variety of effective components in thermal comfort, there is a lack of research on this subject. In addition, researchers believe many relations between these components should be considered in thermal comfort studies. Therefore, as a part of a larger study, this study was conducted to investigate the effect of personal, environmental, and social components on thermal comfort. This study aims to clarify the individual and social components affecting the perception of thermal comfort to provide solutions to improve the design of office spaces. So, there are two questions: First, what are the personal and social factors affecting the perception of thermal comfort? And second, which scale is better for predicting thermal comfort based on these components?Methods: In this regard, a field study (including questionnaire, observation, and on-site measurement for recording climatic data using thermal sensors) was conducted in winter in a main administrative office building of Shiraz University. Questionnaires were designed to gather some of the personal components (such as age, gender, height, weight, and adaptive behaviors); social components (including education and degree level, the field of study, and position); and thermal scales (thermal sensation, thermal comfort, thermal satisfaction, thermal preference, thermal acceptability, and overall thermal comfort). Blood pressure, heart rate, and body temperature as the personal components were measured using a related standard device. Clothing and activity types were recorded and then changed into a quantitative scale. The data loggers also record the indoor air temperature and relative humidity. The field study was conducted in January 2019 for four consecutive days from 8 am to 12 pm. In total, there were 110 measurement subjects. Finally, 108 were identified as useful in the analysis by eliminating incomplete questionnaires. The main administrative building is located on the northern side of Shiraz, Iran (52.52°N, 29.63°E). The 138920 m2 building is oriented in the northwest and southeast in two blocks (with seven and ten stores). The two building blocks have some differences in constructional details and interior design. There was no compulsion to participate, and oral and short-form written consent was considered with no restrictions on participants to have freedom of their usual work day.Findings: The collected data were imported into SPSS software. A total of 22 statistical analyses were performed, including descriptive and inferential statistics (linear and multiple linear regression, Univariate ANOVA). This study selected the correlation coefficients based on the variables scale. So, Spearman, Pearson, and Eta correlation have been used to show the strength of the relations. In this study, 108 subjects participated, including 41 women and 66 men (one person did not mention gender). The age group varies from 24 to 60 years. Most of the age group is in the 31-45 range. These individuals weigh between 50 and 120 kg and have a height of 1.55 to 1.86 meters. The average body temperature was 36°C, the mean blood pressure was 126 with a minimum of 87 and a maximum of 183, and the heart rate was also in the range of 49 to 98. The average indoor air temperature during the four days of study was 23.67°C, and the average relative humidity was 24.86%. The indoor globe temperature was very close to the air temperature (23.50°C). The average outdoor temperature was 15.2°C, and the average relative humidity was 34.9%. The thermal response was considered with nine different thermal scales on the 3,5, and 7-point Likert scale. The average of each response was as follows: Thermal sensation vote (TSV)= -0.4; Thermal comfort=6; Thermal pleasure= 4.78; Temperature preferences= 0.3’ Humidity preferences= -0.18; Velocity preferences= -0.35; Radiation preferences=-0.32; Thermal acceptance= 0.85; & overall thermal comfort= 4.94.Conclusion: The results show that the impact of social components is negligible. However, participants in double and multiple office rooms had better thermal comfort status than in single office rooms. So, if these criteria are considered during the design process, it can help to improve the indoor environmental quality. Regarding the personal components, body mass index and clothing value are the two most influential factors. It is very important to make different thermal adaptation strategies for the occupants to have a right to choose any of them. Therefore, appropriate strategies should be considered for the components needed to provide comfortable conditions in both human resource management and architectural design. In this study, the thermal preference is an appropriate scale for predicting occupants’ thermal needs based on environmental and personal components. The thermal comfort range was calculated based on Griffith’s methods and was 21-26°C. It is very important to know that people feel neutral based on the thermal sensation vote in most office buildings. Still, they usually need temperature, humidity, air velocity, and radiation changes. So in architecture or mechanical engineering, we should not merely rely on thermal sensation vote to decide on heating or cooling setpoints. So, if the setpoint of the studied office building changes from 25°C to 23.6°C, we can anticipate at least a 10 percent reduction in energy consumption. People can adapt to different situations, making them flexible and resilient. But designers should be aware that this adaptation process needs more effort and, of course, more mental, psychological, and physical energy that can reduce occupant’s productivity.

Effect of Gas Types in Double and Triple Pane Windows on Cooling and Heating Loads in Office Buildings in Hot-Humid, hot-dry and Cold Climates in Iran

Jalil Shaeri; Roza Vakilinezhad; Mahmood Yaghoubi

Volume 10, Issue 2 , February 2020, , Pages 211-225

https://doi.org/10.30475/isau.2020.103683

Abstract

In the last decades, increasing world population and carbon dioxide emission, have led to the increasing importance of energy conservation, especially in the building industry. In Iran, ... Read More In the last decades, increasing world population and carbon dioxide emission, have led to the increasing importance of energy conservation, especially in the building industry. In Iran, almost 40 percent of energy is used in the buildings, where the main part of it is wasted through windows. Hence, reducing the amount of heat transfer and insulating the windows is essential. In recent years, glass technology has offered various alternatives for building energy conservation, including window insulation, transparent covering films and integrated dynamic shadings. Multi- pane windows with various glass layers are one of the solutions to control solar heat, sunlight transmission and noise through windows. They are used in combination with shading devices, especially in office buildings. Studies have shown that using multi-pane windows, heat transfer and building energy consumption decrease depending on the different climates and building thermal properties. However, the impact of different types of filling gases and the optimal window type on building energy consumption in different climates has not been studied. In the present study, the effect of double- and triple-glazed windows containing different gases on the cooling and heating loads of a sample office building are investigated. Altering window layers, its thermal properties will change, including heat transfer coefficient, visible transfer rate, the amount of direct sunlight transmission and solar heat transfer coefficient. The Air, Argon, Krypton, Xenon gases and the mixture of them are used for the gap filling between two or three layers of clear glass. The case studies are Bushehr and Bandar Abbas cities with hot-humid climate, Mashhad and Tabriz cities with cold climate and Shiraz, Yazd, Isfahan and Tehran cities with hot-dry climate. In each city, eleven alternatives have been simulated for a typical office building by changing window type and the intermediate gas. The simulations were performed using Design Builder software version 5.02.003 to calculate annual cooling and heating loads for the sample building. Windows in the base model are simple windows with clear glass of three millimeters thickness. According to ASHRIE standard, the heating and cooling set points of 22 °C and 24 °C are considered in the simulations. Comparing total building energy consumption with different types of windows and gases, the proper alternatives are defined. In order to validate the results, DOE-2 simulation software has been used. The building energy consumption in Bushehr City has been examined for the eleven alternatives. Since the difference between two groups of the results is 4 percent, all the results are valid. Based on the results, applying double- and triple-pane windows leads to reduced cooling and heating loads of the sample office building in all studied cities. In Bushehr City, using triple pane windows will result in 12.7 percent reduction in the building cooling load while it would be 10.8 percent by applying double-pane windows. The reduction in building cooling load would be 27.5, 25.6 and 17.3 percent in Tabriz, Mashhad and Shiraz cities if triple-pane windows were used. Using double-pane windows, the cooling load reduction would be 14.6 to 17.3 percent in cities with hot-dry climates and 11.9 percent in Bandar Abbas City. According to the total building energy consumption, the triple-pane window filled with air and Xenon gas is the most appropriate window type in all cases. Using such a type of windows will lead to 14.5, 13.5, 34.2 and 38.2 percent reduction in building energy consumption in Bushehr, Bandar Abbas, Tabriz and Mashhad, respectively. So in cities with hot-dry climate, the application of triple-pane windows filled with air and Xenon gas would reduce the building energy consumption by the average of 22.8 percent. Unlike triple-pane windows, the appropriate alternative among double-pane windows is different in each city. In Bushehr City, double-pane window filled with air and argon gas has the most building load reduction. It is also one of the best choices in Mashhad, Shiraz, Yazd, Isfahan and Tehran cities, however the building energy consumption is best reduced using other alternatives filled with argon or krypton gases. By applying such double-pane windows, the amounts of energy reduction in each city equal to 24.7, 15, 15, 17.8 and 16.3 percent for Mashhad, Shiraz, Yazd, Isfahan and Tehran cities, respectively. In Bandar Abbas and Tabriz cities, the most proper windows are those filled with krypton and xenon with 10.8 and 23.3 percent energy reduction. The results of the present study help designers to select the best double- and triple-glazed windows for office buildings in each city.

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Keywords = Office building

A comparative study of the kinetic movement pattern of a triangular geometric facade regarding natural lighting in an office building in Tehran

Abstract

Identification and assessment of the effect of environmental, personal and social components on thermal comfort in office buildings

Abstract

Effect of Gas Types in Double and Triple Pane Windows on Cooling and Heating Loads in Office Buildings in Hot-Humid, hot-dry and Cold Climates in Iran

Abstract