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The use of information and communication technology as an innovative method of investigating architectural composition and application of materials to achieve optimal conditions of comfort and aesthetics of outdoor spaces (Doctoral thesis)

Στεφανόπουλος, Κυριάκος/ Stefanopoulos, Kyriakos

The study aims, the recording of the conditions that prevail in public outdoor spaces from the point of view of the ambient temperature that ignites, due to the material coatings of these spaces as well as other parameters. The points examined, recorded, mapped and visualized through indirect and direct measurements, using specialized digital instruments and photogrammetric methods. The results of the research in the examined public outdoor spaces are intended to contribute to the outcome of conclusions for the optimal version of the use of materials and forms of configuration (coatings, etc.) for the creation of optimal climatic conditions in terms of the final feeling of temperature and above all the feeling of comfort, the quality of living in the outdoor spaces by the users and by extension to contribute cumulatively to urban planning with the aim of their aesthetic upgrade. The differentiation of the behaviour between the younger ones in relation to the same but older materials, which have been used and exposed for a longer period of time, was also examined in the context of the research. Because the field of research was the old town of Xanthi, the temperature was recorded at different times of the day for a period of six months in selected characteristic points landmarks. the temperature was, on average in their greatest deviation, at 1.71oC lower. From the above we understand the behaviour of materials in solar radiation, the contribution of greenery to temperature control in public spaces and how all of this contributes to improving the sense of air temperature by the users of outdoor public spaces, making them friendlier to use during the summer months when the sunshine is more intense. The conclusions of the research could help in urban planning and the renovations of public common spaces and by extension in the private space. Xanthi, as is well known, is located at the north-eastern tip of Greece in the prefecture of the same name and the Region of Eastern Macedonia and Thrace. To this day, the traditional character of the old town of Xanthi has been preserved and it is a protected settlement. The streets of the old town have always had dark gray granite blocks as paving material, which are placed with a special technique and due to their great durability, they are kept in very good condition for many years. The difference observed in terms of climatic conditions between the city and the region, is greatly influenced by the behaviour of the solar radiation incident and trapped in the ground, the covering materials and the various general constructions. This behaviour also depends on other factors, concerning the covering materials of shared public spaces. The comparison is made between different points within the urban fabric of the old town of Xanthi (see map p.128), which are paved with gray granite blocks. These areas are important platforms, road intersections, but also squares and parking areas. These points have been reconstructed in different time periods, which we know from the archive of the Municipality of Xanthi with projects carried out from 1992 to today. The file belongs to the Department of Technical Services of the Municipality of Xanthi, which is responsible for the projects and interventions in the public common areas of the municipality and includes projects carried out from 1992 onwards because its operation in its current form began in 1990-91. Measurement points 1, 2 and 3 were reconstructed before 1992 because they are not included in the project record, points 4, 5 and 6 were reconstructed in 1998, points 7, 8 and 9 in 2003, points 10, 11 and 12 in 1995 and points 13, 14 and 15 in 1998 (see map p.127). Therefore, another reason for the selection of the points, apart from their importance for the urban fabric of the old town of Xanthi, is the knowledge of the reconstruction date of the measurement points and the age of the coating materials. The areas to be studied were chosen so that during the day and according to the course of the sun, some are exposed to the sun and others in the shade, caused by vegetation or buildings. The aim of this selection was to demonstrate whether the newer or older coating materials in the specific areas behave better or not in terms of the temperature sensation and comfort of their users, as well as drawing conclusions for the future use in aesthetic upgrading applications and generally in urban planning studies. For this reason, the detailed recording of the temperature in the specific areas covered with gray granite blocks was done at the height of a person, and at times when the sun affects the behaviour of the materials more (specifically at 12.00pm, 3.00pm and 6.00pm pm). In addition, a comparison was made between points that were reconstructed at the same year, but also points that were reconstructed at close years. Points that were reconstructed in the same year, specifically 1998, such as points 4 and 14, and points that were reconstructed in nearby years, such as points 4 and 10 with corresponding reconstructions in 1998 and 1995, were compared. The comparison was made at the same time of day, where the measurements were made and for reasons of better comparison between them, the moment in time when the two positions were compared was chosen to be either exposed to the sun or in the shade. The comparison for points 4 and 14 was made for 12:00 p.m. and while they were exposed to the sun, while for points 4 and 10 the comparison was made for 15:00 p.m. and while they were also exposed to the sun. Methodologically, this choice was necessary, so that the worst case of exposure to the sun would not affect the result. The response of sunlight that falls and is trapped on the ground, in the covering materials and in the various structures, increases the temperature of the atmospheric air. On the one hand, the atmospheric air is heated by the sun's rays that penetrate it and on the other by the surface of the earth and structures. During this comparison it was found that the two points compared to each other were very close to the temperatures measured, with a maximum difference of 0.28oC. Also, a comparison was made between points that were constructed or reconstructed at long time intervals between them. In this comparison between points that were reconstructed at long time intervals between each other and specifically before 1992 and 2003, the points chosen were 3 and 8 as well as 1 to 7. Points 7 and 8 were reconstructed in 2003 and points 1 and 3 before 1992 (see Figure 46 p. 161). The comparison was made for the same time of day, when the measurements were made and the same time was chosen, and the two points that were compared were either exposed to the sun or in the shade, so that again do not affect the result in the worst case of exposure to the sun. The measurements were made for the same time of day, specifically at 3:00 pm. and while the points were exposed to the sun (see Table 15 p.155). As we have said, the response of sunlight that falls and is trapped in the soil and in the covering materials, increases the temperature of the atmospheric air in the areas that are exposed to the sun compared to those that are in the shade. During this comparison, it was found that the two points compared to each other had a deviation in the temperatures measured, with a maximum difference of 1.94ºC, while both points are located within the old town of Xanthi in morphologically close areas or areas affected by other conditions. The highest temperatures were measured in the oldest layers with the granite cubes. This leads us to the conclusion that the newer gray granite cubes behave better in terms of temperature sensation than the users of the free public spaces where they have been paved, with a temperature difference that can reach up to 1.94oC. Another topic of the thesis examined during the research is the effect on the temperature and the thermal comfort of the users of the outdoor public spaces due to the existence of tall vegetation in parts of the public space of the old town of Xanthi. The old city has many squares and outdoor platforms that are important passages or meeting and gathering places. Many cultural events take place in these spaces at different times of the year, with the participation of many locals as well as visitors to the city from all over Greece and the neighboring states. The points selected and compared were paved with dark gray granite cubes. The paving of the cuboids stones was and is still done using traditional techniques and due to the protection of the settlement by the Ministry of Culture, the granite cubes are preserved to this day in their entire extent. Repairs and reconstructions of public spaces must be made with the same materials. This is done in order not to alter the character of the settlement and therefore before any work, whether in a public or private space, this work must be approved by the Ministry of Culture. The Municipality of Xanthi, during the restoration of the roads with granite blocks, replaced the old material with a new one, the same as the old one in composition and color. This was because the cobblestones from use and especially from the tires of the cars were smoothed to a great extent, resulting in their slipperiness. A part of the old granite cubes was kept in storage, so that they would be there in case of an emergency spot intervention to repair some problem. The Ministry of Culture usually enforces the use of old materials where possible. This contributes to the economy of natural resources and the money that was spent on the purchase of new materials, but also of the raw material that had been used. However, when the replacement is imposed for practical and utilitarian reasons, it is necessary. From the research we additionally conclude that the granite blocks should be replaced due to the improvement of the thermal sensation by the users in the public common areas where new granite blocks are installed. The aim of the study is, through research and on-site measurements in different outdoor public spaces of the city, to draw conclusions about factors that influence and shape the temperature, as well as the investigation of the behavior and effect of coating materials on the microclimate of the city area, as well as the use of greenery with the aim of improving the urban environment and consequently the thermal sensation of users of public outdoor spaces. Specifically, the thesis aims at the comparative evaluation of the effect of the coating materials of the public outdoor urban spaces on the temperature and the thermal sensation that affects the microclimate of the area and the comparative analysis between measurements to draw conclusions, from measurements made in fifteen different public places outdoor urban spaces during the summer months of the year. After taking the measurements of the temperature parameter that prevailed at the measurement points, an analysis was made of the air temperature that expresses the thermal comfort of the users of the outdoor spaces, where the research was focused. The comparison of temperatures developed in outdoor areas shaded by greenery versus outdoor areas exposed to the sun it was done at two points at the same time and at a close distance, with the difference that one point was during the measurements in the shade caused by trees while the second was exposed to the sun. For this reason, the temperature was recorded at human height, above specific areas that are covered with the same material, i.e. the gray granite cubes, days and hours when the sun affects the behavior of the materials more. Specifically, in spring, summer and autumn, at 12.00pm, 3.00pm and 6.00pm. The instruments that performed the measurements were connected to a hand-held digital meter from the Kimo instruments company. The measuring instrument model is HD 200. To take the measurements, the measuring instrument was moved to the selection points at the appropriate times that had been selected. The measuring instrument was left open for a period of time until the readings stabilized and then recorded and collected. For the purposes of the research, measurements were taken at fifteen different points located in the urban fabric of the old town of Xanthi. And in this case, in all places the coating is made of gray granite blocks. This choice was made so that there is no coating that the coating material affects the results of the measurements due to their difference. Also, in this case, these areas are squares, important platforms, road intersections, but also parking areas. Most of the public open spaces of the old town of Xanthi are paved with granite blocks. When comparing the temperatures at the three time points of the day when the measurements were taken, it was found that in the shade of the trees the temperature was, on average in their greatest deviation, at 1.71oC lower. From the above we understand the behaviour of materials in solar radiation, the contribution of greenery to temperature control in public spaces and how all of this contributes to improving the sense of air temperature by the users of outdoor public spaces, making them friendlier to use during the summer months when the sunshine is more intense. The conclusions of the research could help in urban planning and the renovations of public common spaces and by extension in the private space. For example, in cases of renovations where there are pavements with granite blocks, they should be replaced with new ones, so that they contribute in the summer months to reducing the air temperature of the area up to 2.69oC, and not from recycling building materials. Also, that we may have the benefit of reducing the air temperature by replacing the gray granite blocks, their replacement should be done in an area of at least 0,70 acres which corresponds to about 25.000 pieces of blocks as found by the survey. During the bioclimatic design of outdoor public spaces, in addition to the materials and the wet element, there should also be green spaces with evergreen and deciduous trees, so as to contribute to a lower air temperature in the hot months. The difference may not have been the same in all the parts of the old city that were compared with each other, but it is very important that the temperature was always lower in the shade, with its variations from place to place. The difference between the points measured to be compared reached 1.71oC.