Browsing Department of Mechanical Engineering & the Built Environment by Subjects
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Bioclimatic rehabilitation of an open market place by a computational fluid dynamics simulation assessmentThese days urban design of open spaces is strongly related to bioclimatic techniques and practices. It is here presented the procedure of a bioclimatic study by the use of simulation tools. The area of an open market place is characterized of decreased human thermal comfort conditions during summer time. The employment of computational fluid dynamics has contributed in the understanding of what interventions should be made at the open space in order to succeed the defined thermal related targets. Table of the proposed rehabilitation explains what the interventions would contribute in the improvement of the local environment.
The influence of bioclimatic urban redevelopment on outdoor thermal comfort.One of the greatest environmental challenges for the sustainability of future cities is the mitigation of the urban heat island phenomenon and thus, improvement of outdoor comfort conditions for people. The emphasis of this work is to analyze how mitigation techniques in a dense urban environment affect microclimate parameters and outdoor thermal comfort. The quantitative differentiation of outdoor thermal comfort conditions through bioclimatic urban redevelopment for an area in the city of Serres, Greece is investigated. The main bioclimatic interventions concern the application of cool paving materials, the increase of vegetated areas and the creation of water surfaces. The analysis and comparison are performed for a hot summer day with the ENVI-met model. Software simulations regarding microclimatic and outdoor thermal comfort conditions are performed for the daytime period 06.00–20.00 (14 h) at the height of 1.8 m from the ground. The examined parameters are air temperature, surface temperature and mean radiant temperature (Tmrt). The evaluation of outdoor thermal comfort conditions is conducted using the index PMV (Predicted Mean Vote), adapted for outdoor conditions. The results of simulations are discussed regarding the assessment of bioclimatic interventions.
Use of cool materials and other bioclimatic interventions in outdoor places in order to mitigate the urban heat island in a medium size city in GreeceThe materials that are used in outdoor spaces are of prime importance as they modulate the air temperature of the lowest layers of the urban canopy layer, they are central to the energy balance of the surface and they form the energy exchanges that affect the comfort conditions of city people. Paved surfaces contribute to sunlight's heating of the air near the surface. Their ability to absorb, store and emit radiant energy has a substantial affect on urban microclimate. The thermal behaviour of typical construction materials in an urban center of North Greece, at Serres, was investigated. The thermal fluctuation during the day and the surface temperature differences between different materials in a selected area inside the urban centre of the city was monitored. The replacement of conventional materials with cool materials was evaluated to have significant benefits. CFD simulations showed that materials replacement, accompanied by other mitigation techniques in the area, result at reduction of the mean surface temperature in the streets of the area of 6.5 °C. The results of the measurements and the CFD simulations are presented in the paper.