An analysis of bioclimatic zones and implications for design of outdoor built environments in Egypt

Climate considerations are essential dimensions in the assessment of quality of outdoor built environments. This paper provides an analysis of bioclimatic classification of Egypt to help the environmental design of wide range of purposes, including: climate responsive design; energy conservation and thermal comfort in the outdoor built environments. The analysis of this classification uses a bioclimatic approach in which the comfort zone and monthly climatic lines were determined and plotted on the psychrometric chart. Since the mean radiant temperature (T_mrt) is the most important input parameter for the energy balance in outdoor environments, the charts apply the ASHRAE 55-2004 standard considering the operative temperature as a function of T_mrt. Analysis for each bioclimatic zone determines the potential of passive design strategies to maintain thermal comfort in outdoor spaces and to contribute to energy efficient built environment. Finally, this study suggests a design guideline matrix for landscape architectural design for the different bioclimatic zones.     

Thermal comfort in transitional spaces—basic concepts: literature review and trial measurement

Current thermal comfort research extensively documents various aspects of the human thermal response to stable environmental conditions. Reviews of recent research on outdoor comfort, however, reveals a lack of information on response to conditions in transitional spaces—those areas that are influenced by outdoor climate, yet are architecturally bounded by a building. In this work, we focused on transitional space as a space in between outdoor and indoor. Transitional spaces were organized into three categories depending on their proximity to interior spaces. Pilot measurements of physical variables were taken in six places. Transitional spaces’ physical environments varied by the space type and architectural characteristics. The typical behaviors observed were walking, standing, and sitting —different and varied compared to the sedentary behavior in offices or homes. The most efficient architectural shape of transitional spaces is related to the corresponding regional climatic condition. It was verified that PMV cannot be used for transitional space thermal comfort predictions because of its unstable and dynamic physical and MET value.     

Field study of human thermal comfort and thermal adaptability during the summer and winter in Beijing

This study was conducted during the summer and winter in Beijing. Classrooms and offices in a university were used to conduct the survey. The respondents’ thermal sensation and thermal adaptability in both seasons were analyzed. During the study, indoor environmental parameters including air temperature, mean radiant temperature, relative humidity, and air velocity were measured. The respondents’ thermal sensation was determined by questionnaire.A relationship between indoor temperature and thermal sensation was found. In the summer study, the “scissors difference” between TSV and PMV was observed in the air-conditioned environments if the temperature was out of the neutral zone. People had higher tolerance in the hot environment than PMV predicted. During winter, the outdoor temperature had a prominent influence on thermal adaptability. The low outdoor temperature made people adapt to the cold environment. When the indoor temperature was heated to a high temperature by space heating facilities, respondents felt uncomfortable since their adaptability to the cold environment was nullified.Furthermore, the differences in thermal responses between respondents from North and South China showed that the different climates of people's native regions also affected their thermal comfort and adaptability.     

Determination of bioclimatic comfort in three different land uses in the city of Erzurum,Turkey

This study was carried out to determine the human bioclimatic conditions in rural, urban and urban forest areas in the conditions of the city of Erzurum, where an extreme continental climate type prevails. Data were obtained over a 10-month period and human bioclimatic conditions in these three different land-use types were evaluated using human bioclimatic indices, suitable for the data obtained. In the study, thermohygrometric index (THI), which assesses air temperature and relative humidity, and “beer garden days” index, which uses the days when temperature at 21:00 is over 20 °C, were used. While in these three areas “hot” and “comfort” ranges were determined to be 10% of the period, the number of “beer garden” days was only 20 days in rural, 15 days in urban forest and 18 days in urban areas of Erzurum. Consequently, it has been determined that the most suitable area for the human comfort in the conditions of Erzurum is in the urban area which is followed by the urban forest and the rural areas, both for each observation time and across the whole period.     

Outdoor thermal comfort and outdoor activities: A review of research in the past decade

Outdoor spaces are important to sustainable cities because they accommodate pedestrian traffic and outdoor activities, and contribute greatly to urban livability and vitality. In the global context of climate change, outdoor spaces that provide a pleasurable thermal comfort experience for pedestrians effectively improve the quality of urban living. The influence of thermal comfort on outdoor activities is a complex issue comprising both climatic and behavioral aspects; however, current investigations lack a general framework for assessment. This paper presents a review of research over the past decade on the behavioral aspects of outdoor thermal comfort. The article focuses on perceptions of outdoor thermal comfort and the use of outdoor space in the context of urban planning. We further discuss a general framework for assessing outdoor thermal comfort based on behavioral aspects and the need for predicting tools in the design and planning of outdoor thermal comfort.     

The effect of Urban Heat Island mitigation strategies on outdoor human thermal comfort in the city of Baghdad

Todays, most Iraqi cities suffer from extremely hot-dry climate for long periods throughout the year. However, most urban patterns that exist inside these cities are not suitable for this harsh conditions and lead to an increase in the value of the Urban Heat Island (UHI) index. Consequently, this will increase outdoor human thermal discomfort as well as energy consumption and air pollution in cities. This study attempts to evaluate the effect of UHI mitigation strategies on outdoor human thermal comfort in three different common types of urban patterns in the biggest and most populated city in Iraq, Baghdad. Three different mitigation strategies are used here – vegetation, cool materials, and urban geometry – to build 18 different scenarios. Three-dimensional numerical software ENVI-met 4.2 is utilised to analyse and assess the studied parameters. The input data for simulations process are based on two meteorological stations in Baghdad: Iraqi Meteorological Organization & Seismology, and Iraqi Agrometeorological Network. All measurements are taken in a pedestrian walkway. The results of different scenarios are compared based on their effect on human thermal comfort. Outdoor thermal comfort is assessed according to Predicted Mean Vote index, as mentioned in ISO 7730 standard. This study provides a better understanding of the role of UHI mitigation strategies on human thermal comfort in the outdoor spaces of Baghdad's residential neighbourhoods. This can help generate guidelines of urban design and planning practices for better thermal performance in hot and dry cities.     

Architectural structure and environmental performance of the traditional buildings in Florina,NW Greece

This paper presents various aspects, which characterise the traditional architecture in the town of Florina, north-western Greece, and can be related to bioclimatic and environmental architecture. The study is based on the documentation and the analysis of the architectural and bioclimatic aspects of a sample of forty (40) remaining houses of the 19th and the beginning of the 20th century. The analysis of the architectural aspects concerns the building typology, the form, the materials and the construction techniques, whereas the analysis of bioclimatic aspects involves the thermal behaviour of the building shell, the thermal and the visual comfort conditions. The aim of the study is to document and assess, both qualitatively and quantitatively, all the afore-mentioned aspects in order to draw conclusions concerning the principles, which characterised this architecture and can be integrated to the refurbishment of existing buildings or the design of new ones in traditional surroundings.     

Evaluation of enhanced conduction-corrected modified effective temperature ETFe as the outdoor thermal environment evaluation index

The purpose of this paper is made to clarify that the relationship between the human physiological and psychological responses and the enhanced conduction-corrected modified effective temperature ETFe as the outdoor thermal environment evaluation index upon the human body. Environmental factors and human physiological and psychological responses were measured. It was made clear that the variables by which summer outdoor environmental factors influence the thermal sensation vote are heat conduction, humidity and short-wave solar radiation. The variables that affect the thermal comfort vote are air velocity, heat conduction and humidity. ETFe, into which the environmental factors that are the variables for human response are incorporated, showed good correspondence with the thermal sensation vote. Similarly, ETFe has a good correspondence with thermal comfort vote. The usage of ETFe as a thermal environment evaluation index for summer outdoor spaces is valid. The threshold for the human body with regards to thermal environment stimuli in an outdoor space is higher than the thermal environment stimuli in a summer indoor space.     

Assessing thermal comfort of active people in transitional spaces in presence of air movement

The aim of this study is to develop a modeling methodology to assess thermal comfort and sensation of active people in transitional spaces and consider how comfort can be achieved by air movement while changing upper body clothing properties. The modeling is based on a bioheat model, capable of predicting segmental skin and core temperature from locally ventilated clothed body parts. The bioheat model is integrated with thermal comfort and sensation models to predict comfort in presence of air movement.The model accuracy in predicting comfort was validated by and agreed with the results of a survey administered to subjects wearing typical clothing at different activity levels to record their overall and local thermal sensation and comfort in a transitional space at Beirut summer climate. The transitional space temperature monitored during the experiments ranged between 27 °C and 30 °C.A parametric study is performed to assess thermal comfort in transitional spaces for different air movement levels and for three clothing designs. The high permeable clothing at 1.5 m/s and indoor temperature of 30 °C improved the Predicted Mean Vote to values less than 0.5 compared to 1.01 attained with typical low permeable clothing.     

Numerical Method for a Full Assessment of Indoor Thermal Comfort

Heat, mass and momentum transfer takes place simultaneously in ventilated rooms. For accurate predictions of the indoor environment, all the environmental parameters that influence these transport phenomena should be taken into consideration. This paper introduces a method for a full assessment of indoor thermal comfort using computational fluid dynamics in conjunction with comfort models. A computer program has been developed which can be used for predicting thermal comfort indices such as thermal sensation and draught risk. The sensitivity of predicted comfort indices to environmental parameters is analysed for a mechanically ventilated office. It was found that when the mean radiant temperature was considered uniform in the office, the error in the predicted percentage of dissatisfied (PPD) could be as high as 7.5%. The prediction became worse when the mean radiant temperature was taken to be the same as air temperature point by point in the space. Moreover, disregarding the variation of vapour pressure in the space resulted in an error in PPD of abour 4% near the source of moisture generation. The importance of evaluating both thermal sensation and draught risk is also examined. It is concluded that in spaces with little air movement only the thermal sensation is needed for evaluation of indoor thermal comfort whereas in spaces with air movement induced by mechanical vantilation or air-conditioning systems both thermal sensation and draught risk should be evaluated.     

Selection of window sizes for optimizing occupational comfort and hygiene based on computational fluid dynamics and neural networks

The present paper presents a novel computational method to optimize window sizes for thermal comfort and indoor air quality in naturally ventilated buildings. The methodology is demonstrated by means of a prototype case, which corresponds to a single-sided naturally ventilated apartment. Initially, the airflow in and around the building is simulated using a Computational Fluid Dynamics model. Local prevailing weather conditions are imposed in the CFD model as inlet boundary conditions. The produced airflow patterns are utilized to predict thermal comfort indices, i.e. the PMV and its modifications for non-air-conditioned buildings, as well as indoor air quality indices, such as ventilation effectiveness based on carbon dioxide and volatile organic compounds removal. Mean values of these indices (output/objective variables) within the occupied zone are calculated for different window sizes (input/design variables), to generate a database of input–output data pairs. The database is then used to train and validate Radial Basis Function Artificial Neural Network input–output “meta-models”. The produced meta-models are used to formulate an optimization problem, which takes into account special constraints recommended by design guidelines. It is concluded that the proposed methodology determines appropriate windows architectural designs for pleasant and healthy indoor environments.     

Effect of personal and microclimatic variables on observed thermal sensation from a field study in southern Brazil

Urban climate, which is influenced by land use patterns, heat-generating activities, and the physical texture of urban fabric, has a great impact on outdoor comfort as well as on a building’s energy consumption. A climate-responsive urban planning can provide optimal, comfortable thermal conditions not only for the permanence of humans in outdoor spaces but also reducing the need of air conditioning systems in buildings. The purpose of this article is to present results of an outdoor comfort research with passers-by in downtown Curitiba, Brazil (25°31′S, 917m elevation). Urban locations have been monitored regarding standard comfort variables: air temperature and humidity, wind speed and globe temperature. Alongside the quantitative assessment of comfort conditions, a survey of pedestrian’s thermal comfort perception according to ISO 10551 was carried out on each monitoring campaign by means of questionnaires with the local population. As a whole, from fourteen monitoring campaigns using a couple of weather stations, beginning on January 9 through August 12, 1654 valid comfort votes were obtained. In this paper, we perform a data consistency check, evaluating the relationship between personal (gender and age of respondents) and objective, microclimatic (comfort variables) factors on observed thermal sensation.     

Energy and microclimatic performance of restored hypogeous buildings in south Italy: The “Sassi” district of Matera

The site of the “Sassi of Matera” classified by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as World Heritage in 1993, is an exceptional example of traditional bioclimatic Mediterranean architecture. Within this immense artistic heritage, we find hypogea habitations, stone buildings, and mixed habitation – half-hypogeum and half-built. In this study, we analyze the energy and microclimatic performance of hypogeous structures in three states: not-restored, immediately after restoration, and a few years after restoration (in normal use). We monitored a surface hypogeum and a deep hypogeum. We performed a dynamic parametric simulation using the software EnergyPlus to quantify the energetic balance of the hypogeous structures during one calendar year. The energetic valuation of the surface hypogea shows that these environments, once restored and in a condition of normal use, give indoor comfort within the limits of comfort thermo-hygrometrics established by the comfort indices of predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD). The huge thermal mass of the walls ensures that the microclimate indoor conditions are regular throughout the seasons, without differences in the daily thermal oscillation. Deep hypogea without an air change system cannot reach thermal-hygrometric comfort values. We determined that these structures have a null thermal balance during mid-season, while in the summer the floor loses heat, thereby cooling the environment. The opposite occurs in winter. We can conclude that these buildings were designed as bioclimatic. In fact they can be used, after restoration, with limited use of technology systems.     

Relationship between thermal sensation and comfort in non-uniform and dynamic environments

The relationship between thermal sensation and thermal comfort was studied experimentally under uniform and non-uniform, steady and dynamic conditions separately. Thirty subjects participated in all the experiment and reported their thermal sensation and thermal comfort simultaneously. Thermal sensation and comfort are found to be correlated closely under steady and uniform conditions and the comfort zone of thermal sensation vote in warm side is (0, 1.25). Under steady and non-uniform conditions thermal sensation change with space is found to be an important factor determining thermal comfort. Combining the effects of overall thermal sensation and thermal sensation change with space, a thermal comfort model for steady conditions is proposed. Under dynamic conditions, thermal sensation change with time affects thermal comfort significantly.     

Das städtische Mikroklima: Analyse für die Stadt‐ und Gebäudeplanung

In the face of global warming, human thermal comfort has become an increasing important aspect in applied urban planning. As the urban heat island is not a homogenous factor the microclimate conditions play an important role also for single buildings and the situation inside. For a better consideration of this aspect in the planning process, qualitative and especially quantitative assessment tools are required. To get a better knowledge about the quantitative dimension of urban climates investigations on thermal comfort in outdoor and indoor spaces are carried out in selected city quarters in the city of Kassel in Germany. These studies consist of experimental investigations including field interviews about usage of urban open spaces and thermal sensation and numerical simulations on thermal comfort under recent as well as future regional climate conditions. The added‐value of the interdisciplinary research project is based on the correlation of findings from human‐biometeorology with the outcomes from sociologic questionnaires and building physics, which will be used to plan and design structures in a high spatial resolution. The thermal conditions outside continue inside the building, a combination of internal and external climate considerations must be made. The aim of a research at the University of Kassel is the examination and presentation of different microclimate and its influence on the thermal behavior of buildings.     

Bioclimatic and vernacular design in urban settlements of Brazil

Brazilian regional traditional architectural features are analyzed, especially with regard to the new emerging vernacular of self-built urban settlements. Bioclimatic design is discussed as to its scientific and technical features with respect to the subtropical climate of the city of Campinas in the State of São Paulo, Brazil. The main goal of this work is to analyze a specific self-building house phenomenon and its response to climate. From this analysis thermal comfort should be addressed in terms of correct architectural elements. An appropriate new architecture for the urban poor should be based on bioclimatic design principles and the positive elements of the new urban vernacular.     

Modeling urban microclimate to ameliorate thermal sensation conditions in outdoor areas in Athens (Greece)

Previous research that conducted in three typical public areas in Athens showed that the acceptable air temperature range that determines thermal comfort varies among 17.0–21.0 °C and 26.0–32.0 °C for the cool and the warm period of the year, respectively. The present research goes further and determines the acceptable environmental conditions via two wide acknowledged thermal indices, which are PET and UTCI, in order to evaluate, whether or not, thermal comfort conditions are presented in three typical outdoor urban areas of a Mediterranean city, like Athens. Thus, environmental model ENVI-met 3.1 was applied to calculate the daily microclimatic variation of the three examined areas for the same dates, one typical for the warm period and one typical for the cool period. Thermal sensation conditions were then assessed by the indices. Results showed that the examined areas approach the acceptable environmental conditions only for the cool day, whereas an assumed urban design scenario was able only to ameliorate thermal discomfort but not to reach thermal comfort during a hot day.     

Thermal comfort and IAQ assessment of under-floor air distribution system integrated with personalized ventilation in hot and humid climate

The potential for improving occupants’ thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied by UFAD system and uncomfortable sensation as “warm head” can be reduced by the PV system providing cool and fresh outdoor air at the facial level. A study with 30 human subjects was conducted in a Field Environmental Chamber. The chamber was served by two dedicated systems – a primary air handling unit (AHU) for 100% outdoor air that is supplied through the PV air terminal devices and a secondary AHU for 100% recirculated air that is supplied through UFAD outlets. Responses of the subjects to the PV-UFAD system were collected at various room air and PV air temperature combinations. The analyses of the results obtained reveal improved acceptability of perceived air quality and improved thermal sensation with PV-UFAD in comparison with the reference case of UFAD alone or mixing ventilation with ceiling supply diffuser. The local thermal sensation at the feet was also improved when warmer UFAD supply air temperature was adopted in the PV-UFAD system.     

上海地区适应性热舒适研究

为研究上海地区人体热感觉和适应性热舒适现状,通过环境参数测量和问卷调查结合的方式来分析和探讨室内外气候条件、服装热阻、热感觉等关系。本文主要涉及自然通风建筑内人体热感觉和热中性温度随季节变化的关系。结果表明:在适应性热舒适研究中,人体中性温度与室外环境温度具有较强的相关性,得到的上海地区适应性热舒适模型可为适合我国自身特点的热舒适研究提供依据。     

Assessment of the microclimatic and human comfort conditions in a complex urban environment: Modelling and measurements

Several complex thermal indices (e.g. Predicted Mean Vote and Physiological Equivalent Temperature) were developed in the last decades to describe and quantify the thermal environment of humans and the energy fluxes between body and environment. Compared to open spaces/landscapes the complex surface structure of urban areas creates an environment with special microclimatic characteristics, which have a dominant effect on the energy balance of the human body. In this study, outdoor thermal comfort conditions are examined through two field-surveys in Szeged, a South-Hungarian city (population 160,000). The intensity of radiation fluxes is dependent on several factors, such as surface structure and housing density. Since our sample area is located in a heavily built-up city centre, radiation fluxes are mainly influenced by narrow streets and several 20–30-year-old (20–30 m tall) trees. Special emphasis is given to the human-biometeorological assessment of the microclimate of complex urban environments through the application of the thermal index PET. The analysis is carried out by the utilization of the RayMan model. Firstly, bioclimatic conditions of sites located close to each other but shaded differently by buildings and plants are compared. The results show that differences in the PET index amongst these places can be as high as 15–20 ^°C${}^{°}\mathrm{C}$ due to the different irradiation. Secondly, the investigation of different modelled environments by RayMan (only buildings, buildings+trees$\mathrm{buildings}+\mathrm{trees}$ and only trees) shows significant alterations in the human comfort sensation between the situations.