Journal of Iranian Architecture & Urbanism(JIAU)

Analogy of thermal comfort with the influence of openings by PMV method in traditional houses and apartments in Shiraz

Zahra Barzegar; Khatereh Sajjadi

Volume 14, Issue 1 , August 2023, , Pages 117-131

https://doi.org/10.30475/isau.2023.231996.1424

Abstract

Extended AbstractBackground and Objectives: Humans have always tried to build shelters in nature that are compatible with the climate to provide the best conditions for their survival. ... Read More Extended AbstractBackground and Objectives: Humans have always tried to build shelters in nature that are compatible with the climate to provide the best conditions for their survival. Exploiting the climate and weather conditions of each region in architecture is one of the important issues that has attracted the attention of Iranian and foreign researchers in architecture and urban planning research, and it has even influenced the quality of domestic architecture. In addition, in today’s science, it is proven that design will be a very costly process without considering the features and climatic factors. One of the most important factors that is effective in improving the quality of the indoor environment is the concept of thermal comfort. Thermal comfort is a mental condition that expresses satisfaction with the thermal environment. According to the important role of the openness as an index of control of comfort conditions and air flow in the interior, it will play an important role. Investigating the capabilities and comparing the internal thermal comfort of residents under the influence of construction openings are studied the present research.Methods: The current research method is quantitative and thermal comfort is calculated by PMV method. At first, the thermal comfort of the traditional and modern houses changed under the influence of construction openings in the hot season is investigated, then the Percentage People Dissatisfied (PPD) was compared in both open and closed openings in modern and traditional houses and ultimately the most effective factor in reducing the amount PPD dissatisfaction is estimated. In order to investigate the performance of openings in the semi-hot and dry climate of Shiraz, temperature, humidity and wind were measured by a data logger and, with the help of estimation of dissatisfaction and PPD, PMV was extracted. Therefore, in the process of research, a comparison was made between the internal thermal comfort of a traditional house and a modern apartment, and the analyzes were made under the influence of openness in two different states; The first opening mode is fully open and the second opening mode is closed. Opening windows has a great effect on thermal comfort as well as reducing energy consumption, so its correct evaluation is important and accordingly, the newly developed opening model is designed based on the activity pattern and density of people.Findings: In examining the results of field observations and comparing internal thermal comfort under the influence of openings in a traditional house and a modern apartment in Shiraz through PMV calculation, the effect of each of the factors of temperature, humidity and wind speed on the amount of PMV was analyzed. The results of the research indicate that the predicted percentage of dissatisfaction with the predicted mean vote in open window mode at traditional house is 18% and close mode is 59%. This index in open window at apartment is 61% and close mode is 91%. The opening studied in the traditional house was the five-door opening; therefore, it played a more significant role in creating indoor thermal comfort. Conclusion: The thermal suitability of the indoor environment of the building, in addition to providing comfort for the residents, will save energy, enhance health and productivity and also improve the morale of the residents. In the present research, openness and opening of the most important indicators of comfort conditions in the interior space were investigated and functionally evaluated. Therefore, the five-door of the traditional house played an effective role in creating thermal comfort. The analysis of the research shows that the design of the types of openings, the dimensions and sizes of the openings in traditional buildings are such that the opening of the interior spaces are within the comfort range during most of the hot season. The noteworthy point of the opening dimensions is the approximate equality of the opening area with the total area of transparent surfaces, their frequency and repetition, as well as the optimal fit of the opening dimensions with the dimensions of the interior space. In general, it can be assumed that opening will play an effective role in indoor cooling and ventilation. What is so much considered today in sustainable design is featured in the principles of Iranian architecture, which is known as an amenity in building spaces. Subsequently, the quality of the indoor environment depends on other factors, such as the quality of light, visibility and scenery, in addition to thermal comfort.

Improving the climate performance of solar chimneys for Ahvaz houses in south equator-facing rooms

Omid Rahaei; Zeynab Poorsayahi

Volume 13, Issue 1 , May 2022, , Pages 245-257

https://doi.org/10.30475/isau.2022.221907.1365

Abstract

Extended AbstractBackground and Objectives: Today, the use of solar energy as a cheap and renewable source in the construction industry has become one of the major concerns worldwide. ... Read More Extended AbstractBackground and Objectives: Today, the use of solar energy as a cheap and renewable source in the construction industry has become one of the major concerns worldwide. One way to harness solar power is to use a solar chimney in the building. The solar chimney acts as a passive natural ventilation system or as a thermal insulator based on pressure displacement caused by air pressure fluctuations inside the chimney shaft. This chimney usually consists of glass, duct, and absorber surface. The air in the chimney is heated by solar energy and moves upwards due to the chimney effect, which can increase the natural ventilation in the adjacent spaces. In hot and semi-humid climate buildings, windows are usually closed to prevent direct sunlight. Therefore, solar chimneys can establish airflow and supply fresh air indoors. The ventilation process in buildings of Ahvaz city, due to particular climatic conditions (hot and semi-humid), is essential. Also, air conditioning is costly, consuming a great amount of energy. Therefore, this study aims to find appropriate criteria for the effective design and implementation of solar chimneys in houses in Ahvaz to establish an effective flow inside the air duct in seasons requiring thermal comfort conditions and to create effective ventilation inside the interior spaces through stack effect. This study aims to find a suitable model for designing solar chimneys for the southern (equator-facing) rooms of houses in Ahvaz city (hot and semi-humid climate) to improve the thermal comfort of residents by using solar energy effectively and reducing energy consumption significantly.Methods: This research combines different methods due to its interdisciplinary nature. Research variables and models were identified in the first stage using an experimental strategy. The physical structure of the room and the solar chimney were studied as independent variables and the room interior temperature as a dependent variable in this study. A digital thermometer was used for experimental thermometry tests in the case sample. The statistical population selected in this study includes southern rooms in apartments in Ahvaz. The statistical population is a small room as a random case sample. In the next step, solar chimneys were modeled in Ecotect software, and a simulation method was used to analyze the data and intervene in the architecture. The simulations were performed using Energy Plus software version 8.7.0 and the existing weather data (regarding the literature). Also, the simulations were calculated linearly and thermodynamically by TARP thermal model method prepared by Walton (1983) in the software. The Fangar comfort model, PMV index, and PPD were used in the next step of data analysis. Finally, the experimental data were compared to the simulated data to investigate research validity and reliability. Thus, the research method is a combination of experimental strategies, simulation, and a case study. Bibliographic studies, field observations, field measurements, and simulations were used as research tools.Findings: In this study, four different models of solar chimneys on a specific day were studied to investigate the effect of geometry on the model discharge. Also, the thermal comfort (of the first model) was studied on a specific day of the year. (The reason for choosing this model is to investigate the chimney effect on the whole space). The simulation data of the first model with dimensions of 1 × 1.16 × 11.60 showed that the thermal comfort level in this type of solar chimney is close to the allowable limit in March, April, May, June, October, and, November, December. According to the diagrams, using this type of chimney is unsuitable in July, August, and September, so this model is not approved. On May 1st, the effect of the number of floors on the thermal performance of the first model was investigated. The results showed that the solar chimney discharge does not always lead to acceptable thermal comfort conditions. Also, four specific geometries were compared regarding the effect of geometry on the solar chimney discharge. According to findings, the solar chimney height was more effective in determining the maximum and average solar chimney flow than its width. According to the results, the third model has a more powerful airflow but drops to zero at certain hours and has no night ventilation. So, having a chimney with a maximum flow is not necessarily appropriate. The best model, according to the comparative method, is the second model with dimensions (2 × 1.16 × 11.60), and then the third model with dimensions (1 × 1.16 × 23.20), with strong airflow powers.Conclusion: By examining the airflow and thermal comfort conditions in solar chimneys, it was determined that the airflow could create suitable comfort conditions in the building annually. Therefore, the solar chimney with dimensions of 2 × 1.16 × 11.60 (model 2) is suitable for equator-facing rooms with dimensions of 3.5 × 5.9 meters in Ahvaz and can provide comfort levels in the mentioned months. According to the results, this system is needed all year round. When there are no comfort conditions, it is recommended to benefit from mechanical systems, ventilation and air conditioning, green space, and natural ventilation systems for comfort conditions.

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.

Comparative Study of Thermal Comfort Simulation Software in Urban Environment

Roza Vakilinezhad

Volume 12, Issue 2 , December 2021, , Pages 235-250

https://doi.org/10.30475/isau.2020.217902.1353

Abstract

Extended AbstractBackground and Objectives: Energy simulation in an urban environment can be accomplished considering two major objectives: first by analyzing the environmental thermal ... Read More Extended AbstractBackground and Objectives: Energy simulation in an urban environment can be accomplished considering two major objectives: first by analyzing the environmental thermal comfort and second by defining the impact of the environment on buildings energy consumption. Three factors affect the creation of pedestrian thermal comfort including climate (global radiation, air temperature, relative humidity and wind speed), microclimate (sky view factor, direct and indirect radiation, mean radiant temperature, surface temperature, ground temperature, building and ground albedo) and pedestrian physical properties (metabolic activity and coatings; these factors are usually not considered in current software. In order to evaluate the thermal components of urban or regional climates, it is necessary to gather accurate data about the radiant conditions in the surrounding environment. This data can be measured experimentally or calculated using the appropriate radiation model. Thus, there are two general methods of using questionnaires and computational simulations to evaluate the effective factors. For applying energy simulation, selecting the proper tool is the first step, which would not be possible without a detailed understanding of how the tool works. On the other hand, it is difficult to choose the proper tool among the growing number of simulation software. Considering designers’ recent tendency in this field, it is essential to be aware of the modeling capabilities and limitations of each tool. Some studies have compared the capabilities of building energy software, but no similar studies have been done on the urban scale.Methods: By identifying outdoor thermal indices, this study classifies different types of energy simulation at urban scale while introducing six software of Envimet, Rayman, UMI, Meteodyn, Solene and SOLWEIG for pedestrian thermal comfort evaluation. This study aims to define the capabilities, potential, weakness and efficiency of the mentioned software in urban environment. By applying comparative and logical analysis research method, the study is conducted in four steps. In the first step, outdoor thermal comfort indicators have been identified considering effective factors in creation of urban microclimate. The second step is dedicated to identification and classification of related software to be distinguished from urban energy analysis software. In the third step, software performance and the related features are examined and in the final step, selected software properties have been compared in different fields to define strengths, weaknesses and proper application. Capability of the above-mentioned software are compared in terms of climatic parameters, outdoor thermal comfort indicators, solving equations, defaults and neglected factors, extractable parameters, numerical and graphical output data, application simplicity, interaction with other software, graphical interface, accessibility and cost.Findings: In order to perform a simulation with proper accuracy, it is necessary to consider three basic models of radiation, heat transfer and CFD airflow in combination with each other. However, in many energy simulation tools, some equations in the analysis process are overlooked for simplification. In Envimet and Solene software, the three equations are analyzed. The analysis in Rayman, SOLWEIG and UMI models is based on the radiation and heat transfer models only ignoring the airflow model that is assumed to be constant. In Meteodyn, the radiation model in Urbasun and the airflow model in Urbawind tool are analyzed. In Envimet and Solone, four parameters of dry temperature, relative humidity, wind speed and radiant temperature are calculated. Apart from wind speed, Solone calculates three other parameters, while in Rayman, dry temperature and radiant temperature are considered regardless of relative humidity and wind speed. The only parameter examined in UMI and Meteodyn is wind speed.Conclusion: By computing radiant fluxes, Rayman calculates six thermal comfort indicators. Envimet and Solone calculate four indicators including PMV, PET, UTCI, and MRT and in SOLWEIG model, three indicators including PET, UTCI, and MRT are calculated, while none of the common indicators for thermal comfort is listed as the output data in UMI and Meteodyn. Envimet, Solene and Rayman provide more outdoor thermal comfort indicators as output results. In UMI and Meteodyn data is estimated as the average radiation and wind speed while in other the tools it could be extracted precisely at any desired time. While UMI is a simple free tool, using Envimet and Solene is not free and requires training. However, currently no single tool considers the best combination of all factors and includes all physical processes. The results of this research can help architects, urban designers and software users to choose the proper software in each design stage considering project goals.

Evaluating the effective environmental factors on the satisfaction of patients and companions with the patient’s rooms in Tehran hospitals

Hani Hadadzadegan; Zahra Sadat Zomorodian; Mohammad Tahsildoost; Shadi Jamy

Volume 12, Issue 1 , June 2021, , Pages 251-264

https://doi.org/10.30475/isau.2021.118129

Abstract

Extended Abstract Background and Objectives: Various studies confirm that indoor environmental quality (IEQ) evaluation plays an important role in health, wellbeing, and satisfaction, ... Read More Extended Abstract Background and Objectives: Various studies confirm that indoor environmental quality (IEQ) evaluation plays an important role in health, wellbeing, and satisfaction, especially in healthcare facilities. Moreover, these building types are among the major energy consumers. The variety of the users’ requests (patient, patient companion, and staff), physiological conditions, and mental sensitivities increase the importance of choosing the appropriate method of studying healthcare buildings. Previous studies have suggested many methods for assessing indoor environmental quality. Recent research has found IEQ to be largely influenced by thermal comfort, acoustic comfort, lighting comfort, and indoor air quality. Also, due to the differences in users’ perceptions of the limits set in the relevant standards and conditions in hospitals, questionnaires were used to compare the users’ satisfaction with standards and real situations. The main purpose of this study is to evaluate the quality of the patient’s room indoor environment in order to identify the most important indoor quality indices affecting user satisfaction and compare environmental conditions with existing standards such as American Society of Heating, Refrigerating and Air-Conditioning Engineers (Ashare) standard, world health organization (WHO), Iran standards, etc. in this field. In this regard, physical measurements data of environmental parameters affecting the quality of the indoor environment in medical centers were collected. Then by comparing the results obtained from the users’ questionnaires and physical measurements with related standards and previous research, the most important factor influencing indoor environment quality in patient’s room is identified. Finally, the relationship between the type of users who are separately affected by indoor conditions is expressed. Methods: In the current study, based on the results of previously validated studies, the physical data and users’ satisfaction levels are measured via questionnaires to assess the hospitals’ indoor environment quality. Indoor environment quality evaluation is generally studied using the four main characteristics of thermal, lighting, acoustic, and indoor air quality. Five hospitals in Tehran have been selected, and their IEQ has been evaluated. In this regard, 482 questionnaires were completed by the patients and their companions. In these questionnaires, four indices mentioned above, out of the total indices affecting indoor quality, were evaluated. At the same time, these indices have been compared using environmental characteristics such as dry air temperature, relative humidity, lighting intensity, and sound level intensity, carbon dioxide concentration (CO2), fine particulate matter smaller than 2.5 micrometers (PM 2.5) concentration by the researcher, simultaneously with the completion of the questionnaire by users under specific protocols. Findings: Based on the results, the highest compliance with the standard was observed in indoor air quality (IAQ) and the lowest in sound quality according to the World Health Organization (WHO) standards. The results show that there is a significant correlation between the thermal and optical indices concerning indoor quality, which are 0.59 and 0.42, respectively. However, the two indices of acoustic quality and IAQ, despite their high correlation with indoor quality (0.62 and 0.67, respectively), have an internal source. Comparing the frequency of case samples within the standard temperature range (23-26°C) with other cases shows an 11% increase in user dissatisfaction due to non-compliance with this range. Conclusion: Although the acoustic quality of most case samples is out of standard, 30 to 40% of users have reported usual satisfaction with the sound condition. Due to the excess of standard lighting intensity in most case samples, lighting quality has maintained the average level of user satisfaction at the highest level. Also, comparing the results of the users’ satisfaction in the questionnaire with the standard range of the four indoor environmental quality indices stated 100% compliance with indoor air quality, 68% with thermal status, and 18% with lighting status. The results also showed that acoustic status had no significant relationship with standard range and user satisfaction conditions. Also, the dry air temperature factor in evaluating thermal quality is more effective than the relative humidity. Based on the data collected from the statistics, a statistical model is presented to identify the general users’ satisfaction with IEQ based on environmental parameters.

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Keywords = Thermal Comfort

Analogy of thermal comfort with the influence of openings by PMV method in traditional houses and apartments in Shiraz

Abstract

Improving the climate performance of solar chimneys for Ahvaz houses in south equator-facing rooms

Abstract

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

Abstract

Comparative Study of Thermal Comfort Simulation Software in Urban Environment

Abstract

Evaluating the effective environmental factors on the satisfaction of patients and companions with the patient’s rooms in Tehran hospitals

Abstract