Bioclimatic rehabilitation of an open market place by a computational fluid dynamics simulation assessment

These 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 authors greatly acknowledge the support of the Mayor of Eordaia Mrs Paraskevi Vrizidou during all simulation stages. ANSYS-CFD simulations were carried out in the framework of student instruction and demonstration of the Department of Environmental Engineering, Democritus University of Thrace in Greece

Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season

This study analyzed how the variations of plant area index (PAI) and weather conditions alter the influence of urban green infrastructure (UGI) on microclimate. To observe how diverse UGIs affect the ambient microclimate through the seasons, microclimatic data were measured during the growing season at five sites in a local urban area in The Netherlands. Site A was located in an open space; sites B, C, and D were covered by different types and configurations of green infrastructure (grove, a single deciduous tree, and street trees, respectively); and site E was adjacent to buildings to study the effects of their façades on microclimate. Hemispherical photography and globe thermometers were used to quantify PAI and thermal comfort at both shaded and unshaded locations. The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions. Monthly variations in the differences of mean radiant temperature (∆Tmrt) between shaded and unshaded areas followed the same pattern as the PAI. Linear regression showed a significant positive correlation between PAI and ∆Tmrt. The difference of daily average air temperature (∆Ta) between shaded and unshaded areas was also positively correlated to PAI, but with a slope coefficient below the measurement accuracy (±0.5 °C). This study showed that weather conditions can significantly impact the effectiveness of UGI in regulating microclimate. The results of this study can support the development of appropriate UGI measures to enhance thermal comfort in urban areas

On the thermal characteristics and the mitigation potential of a medium size urban park in Athens, Greece

Measurements have been performed during summer in and around a medium size urban park located in the western part of Athens, Greece. Additional temperature data from 15 urban and suburban stations are used to perform comparative analysis at the city level. The park presents an important temperature inhomogeneity during both day and night. Average nocturnal cool island intensities against the reference urban stations varied between -0.7. K and -2.8. K, while during the daytime the average maximum cool island intensity (CII) was between -0.2. K and -2.6. K. A statistical significant correlation between the CII and the population density is found for both day and night. The park was warmer than the urban stations for ambient temperatures lower than 34. °C, while for higher urban temperatures the park was cooler and the absolute CII increased as a function of the ambient temperature. An important correlation with the wind speed is observed for wind speeds higher than 6. m/s. The mitigation potential of the park was assessed by performing three types of traverses around the park. The park cooling intensity was varying between 3.3 and 3.8. K, while the temperature gradient along the traverses changes as a function of the thermal properties of the urban areas and was between 0.2 and 1.4. K/100. m. The park cooling intensity presents a strong correlation with the wind speed for values higher than 5. m/s. The climatic influence of the park was extended up to 300. m from the borders of the park. © 2013 Elsevier B.V