Marialena Nikolopoulou

Thermal comfort and psychological adaptation as a guide for designing urban spaces

Investigating thermal comfort conditions in outdoor urban spaces, has thrown some light on the complexity of the issues involved, demonstrating that a quantitative approach is insufficient in describing comfort conditions outdoors. It revealed that although microclimatic parameters strongly influence thermal sensation, they cannot fully account for the wide variation between objective and subjective comfort evaluation, whereas, psychological adaptation seems to becoming increasingly important. This paper concentrates on the issue of psychological adaptation: naturalness, expectations, experience (short-/long-term), time of exposure, perceived control and environmental stimulation, and presents an attempt to try and evaluate the relative impact of each of these parameters. Understanding the interrelationship between the different parameters of psychological adaptation would be of interest in order to compare their relative significance, and to assess their design role, that is whether design considerations would influence these parameters, or vice versa, whether they could influence design decisions. An awareness of these issues would be valuable to architects, planners and urban designers, not by the way of limiting possible solutions, rather by enriching the design possibilities.

Vegetation in the urban environment: microclimatic analysis and benefits

This paper describes work that was carried out by CRES, in the frame of the EU-funded Joule project “PRECis: assessing the potential for renewable energy in cities.” The main aim of the project is to develop simplified parameters that describe the microclimate and environmental performance of different urban textures. One of the roles of CRES within the team was to describe simplified parameters for the use of vegetation in the urban context, which can eventually be used irrespective of site-specific characteristics for different climatic contexts and urban textures. Of particular interest is the effect of vegetation on microclimate: thermal effects, as well as the effect of vegetation on solar and daylight access. These affect the microclimate of the existing open spaces as well as the energy use of the surrounding buildings for heating, cooling and lighting, through shading, evapotranspiration, etc. Simple parametric studies were examined, to identify the thermal impact of vegetation in the urban environment, at the scale of the urban block, particularly as far as the reduction of air temperature is concerned.

Outdoor thermal comfort

A review of the various approaches in understanding outdoor thermal comfort is presented. The emphasis on field surveys from around the world, particularly across Europe, enables us to understand thermal perception and evaluate outdoor thermal comfort conditions. The consistent low correlations between objective microclimatic variables, subjective thermal sensation and comfort outdoors, internationally, suggest that thermophysiology alone does not adequate describe these relationships. Focusing on the concept of adaptation, it tries to explain how this influences outdoor comfort, enabling us to inhabit and get satisfaction from outdoor spaces throughout the year. Beyond acclimatization and behavioral adaptation, through adjustments in clothing and changes to the metabolic heat, psychological adaptation plays a critical role to ensure thermal comfort and satisfaction with the outdoor environment. Such parameters include recent experiences and expectations; personal choice and perceived control, more important than whether that control is actually exercised; and the need for positive environmental stimulation suggesting that thermal neutrality is not a pre-requisite for thermal comfort. Ultimately, enhancing environmental diversity can influence thermal perception and experience of open spaces.

Seasonal differences in thermal sensation in the outdoor urban environment of Mediterranean climates – the example of Athens, Greece

Outdoor urban areas are very important for cities and microclimate is a critical parameter in the design process, contributing to thermal comfort which is important for urban developments. The research presented in this paper is part of extensive field surveys conducted in Athens aimed at investigating people’s thermal sensation in a Mediterranean city. Based on 2313 questionnaires and microclimatic data the current work focuses on the relative frequencies of people’s evaluation of the thermal along with the sun and wind sensations between two seasons trying to identify the seasonal differences in thermal sensation. The impact of basic meteorological factors on thermal discomfort with respect to season are also examined, as well as the use of the outdoor environment. Results show that psychological adaptation is an important contributing factor influencing perception of the thermal environment between seasons. In addition, the thermal sensation votes during the cool months show that individuals are satisfied to a great extend with the thermal environment whereas the combination of high air temperature, strong solar radiation and weak wind lead to thermal discomfort during summertime. As far as the appropriate urban design in the Mediterranean climate is concerned, priority should be given to the warm months of the year.

Outdoor thermal sensation in a Mediterranean climate (Athens): The effect of selected microclimatic parameters

The present study deals with the estimation of human thermal sensation zones in a Mediterranean climate (Athens). Field monitoring along with field surveys leading to a database of 2313 questionnaires were carried out in three open urban areas. Thermal sensation conditions were analysed under the influence of air temperature, relative humidity, solar radiation and wind speed. Thermal sensation zones were first defined using air temperature as a single parameter affecting thermal sensation. Logistic regression was appropriately used to define each thermal sensation zone. The thermal sensation zones were then determined using a combination of the microclimatic parameters to investigate the extent to which these parameters affect thermal sensation. Results showed that the thermal comfort zone is characterized by a quite wide air temperature range, on the order of more than 10°C. In addition, this zone presents always statistical insignificance in the P-values of residuals. These results imply that thermal comfort is a complex situation and adaptation plays an important role as far as this zone is concerned. By contrast, the other thermal sensation zones were found to present statistical significance in the P-values of residuals, implying thus that the examined microclimatic parameters seem quite adequate to define these zones.

From Construction to Operation: Achieving Indoor Thermal Comfort via Altering External Walls Specifications in Egypt

The objective of this research is to study the effect of using different material specifications for the external walls on the cost of the energy consumption for achieving internal thermal comfort. We refer to this as operation running cost, which in turn is compared to initial construction cost for each type of the used external walls. In order to achieve this objective, dynamic thermal simulation were carried out for four different types of external walls – commonly used in Egypt – in two different sets of cooling: natural ventilation and mechanical means. Experiments recommend that using the Egyptian Residential Energy Code (EREC) to achieve inner thermal comfort with the minimum energy consumption (consequently the minimum CO2 emissions) and the minimum running cost as well.

Urban geometry, SVF and insolation of open spaces: London and Paris

ABSTRACT The radiant environment in open spaces is very sensitive to the surrounding built form, which determines their openness to the sky and exposure to the sun. This paper presents the analysis of 132 urban forms in London and Paris, two cities at similar geographical latitude, but of different urban geometry, focusing on the relationship between urban geometry and insolation of open spaces at neighbourhood scale. The method consists of three stages: (1) the geometric analysis of the urban forms, (2) their solar access analysis and (3) the statistical exploration of the results. Special emphasis is on the sky view factor (SVF), which is employed as an integrated geometry variable and environmental performance indicator. The comparative analysis of the two cities underlines the significance of urban layout for modifying the outdoor radiant environment, and reveals temporal characteristics of the relation between urban geometry and insolation of urban forms, induced by the varying solar geometry. Indicatively, the average mean ground SVF (mSVF) was found to be primarily affected by the quantitative characteristics of the open space, and able to predict average daytime insolation on March 21 and June 21 (R2 > 0.8), in both cities.

Dataset on daytime outdoor thermal comfort for Belo Horizonte, Brazil.

This dataset describe microclimatic parameters of two urban open public spaces in the city of Belo Horizonte, Brazil; physiological equivalent temperature (PET) index values and the related subjective responses of interviewees regarding thermal sensation perception and preference and thermal comfort evaluation. Individuals and behavioral characteristics of respondents were also presented. Data were collected at daytime, in summer and winter, 2013. Statistical treatment of this data was firstly presented in a PhD Thesis (“Percepção sonora e térmica e avaliação de conforto em espaços urbanos abertos do município de Belo Horizonte – MG, Brasil” (Hirashima, 2014) [1]), providing relevant information on thermal conditions in these locations and on thermal comfort assessment. Up to now, this data was also explored in the article “Daytime Thermal Comfort in Urban Spaces: A Field Study in Brazil” (Hirashima et al., in press) [2]. These references are recommended for further interpretation and discussion.

Shaping pedestrian movement through playful interventions in security planning: what do field surveys suggest?

Abstract The control and shaping of pedestrian movement recurs as an aspect of security planning for crowded spaces. Using the concepts of triangulation, performance and flow, this paper presents a series of experiments designed to shape pedestrian movement patterns in public spaces in different spatial and operation contexts, by eliciting noticeable behaviours and disrupting routine use of space. The hypothesis investigated is that playful, non-obstructive interventions foster a positive social experience yet can be used to shape pedestrian movement. The interventions examined were around the themes of floor marking and mirrors. Analysis demonstrated that the interventions were able to create zones of attraction and exclusion, engage people’s curiosity and elicit playful actions. Habituation, goal-directed behaviour and the influence of increased cognitive load at personal level were all important factors responsible for reducing the level of engagement with an intervention. The results suggest that increased understanding between environmental and interpersonal stimuli and behavioural responses can provide guidance in using socially acceptable design interventions to influence use of space in different operational contexts, contributing to sustainable security.

Advances in Urban Biometeorology

1 Laboratory of Climatology and Atmospheric Environment, University Campus, University of Athens, 15784 Athens, Greece 2Meteorology and Climatology, Albert-Ludwigs-University of Freiburg, Werthmannstrase 10, 79085 Freiburg, Germany 3 Kent School of Architecture, University of Kent, Canterbury, Kent CT2 7NR, UK 4Department of Architecture, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan