Assessment of the effectiveness of cool and green roofs for the mitigation of the Heat Island effect and for the improvement of thermal comfort in Nearly Zero Energy Building

2014 ◽  
Vol 58 (2) ◽  
pp. 134-143 ◽  
Author(s):  
Elisa Di Giuseppe ◽  
Marco D'Orazio
Keyword(s):  
Thermal Comfort ◽  
Green Roofs ◽  
Heat Island ◽  
Zero Energy ◽  
Island Effect ◽  
Zero Energy Building

scholarly journals The Effects of Green Roofs on Outdoor Thermal Comfort, Urban Heat Island Mitigation and Energy Savings

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 123 ◽  
Author(s):  
Guglielmina Mutani ◽  
Valeria Todeschi
Keyword(s):  
Surface Temperature ◽  
Thermal Comfort ◽  
Urban Heat Island ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Green Roofs ◽  
Heat Island ◽  
Urban Context ◽  
Urban Heat ◽  
The City

There is growing attention to the use of greenery in urban areas, in various forms and functions, as an instrument to reduce the impact of human activities on the urban environment. The aim of this study has been to investigate the use of green roofs as a strategy to reduce the urban heat island effect and to improve the thermal comfort of indoor and outdoor environments. The effects of the built-up environment, the presence of vegetation and green roofs, and the urban morphology of the city of Turin (Italy) have been assessed considering the land surface temperature distribution. This analysis has considered all the information recorded by the local weather stations and satellite images, and compares it with the geometrical and typological characteristics of the city in order to find correlations that confirm that greenery and vegetation improve the livability of an urban context. The results demonstrate that the land-surface temperature, and therefore the air temperature, tend to decrease as the green areas increase. This trend depends on the type of urban context. Based on the results of a green-roofs investigation of Turin, the existing and potential green roofs are respectively almost 300 (257,380 m2) and 15,450 (6,787,929 m2). Based on potential assessment, a strategy of priority was established according to the characteristics of building, to the presence of empty spaces, and to the identification of critical areas, in which the thermal comfort conditions are poor with low vegetation. This approach can be useful to help stakeholders, urban planners, and policy makers to effectively mitigate the urban heat island (UHI), improve the livability of the city, reduce greenhouse gas (GHG) emissions and gain thermal comfort conditions, and to identify policies and incentives to promote green roofs.

scholarly journals Influence of Weather Factors on Thermal Comfort in Subtropical Urban Environments

2020 ◽  
Vol 12 (5) ◽  
pp. 2001 ◽  
Author(s):  
Chih-Hong Huang ◽  
Hsin-Hua Tsai ◽  
Hung-chen Chen
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Thermal Environment ◽  
Urban Environments ◽  
Heat Island ◽  
Weather Factors ◽  
Urban Forms ◽  
Thermal Environments ◽  
Island Effect ◽  
Urban Heat

Urbanization has influenced the distribution of heat in urban environments. The mutual influence between weather factors and urban forms created by dense buildings intensify human perception of the deteriorating thermal environment in subtropics. Past studies have used real-world measurements and theoretical simulations to understand the relationship between climate factors and the urban heat island effect. However, few studies have examined how weather factors and urban forms are connected to the thermal environment. To understand the influence of various weather factors on urban thermal environments in various urban forms, this study applied structural equation modeling to assumptions of linear relationships and used quantitative statistical analysis of weather data as well as structural conversion of this data to establish the structural relationships between variables. Our objective was to examine the relationships among urban forms, weather factors, and thermal comfort. Our results indicate that weather factors do indeed exert influence on thermal comfort in urban environments. In addition, the thermal comfort of urban thermal environments varies with location and building density. In hot and humid environments in the subtropics, humidity and wind speed have an even more profound impact on the thermal environment. Apparent temperature can be used to examine differences in thermal comfort and urban forms. This study also proved that an urban wind field can effectively mitigate the urban heat island effect. Ventilation driven by wind and thermal buoyancy can dissipate heat islands and take the heat away from urban areas.

scholarly journals Effect of Substrate Depth and Planting Season on Sedum Plug Survival on Green Roofs

2007 ◽  
Vol 25 (2) ◽  
pp. 95-99 ◽  
Author(s):  
Kristin L. Getter ◽  
D. Bradley Rowe
Keyword(s):  
Survival Rates ◽  
Green Roofs ◽  
Heat Island ◽  
Major Objective ◽  
Island Effect ◽  
Successful Establishment ◽  
Urban Heat ◽  
Growing Conditions ◽  
Substrate Depth ◽  
Planting Season

Abstract Green roofs, a roofing technology that entails growing plants on rooftops, provide many benefits such as improved stormwater management, energy conservation, mitigation of the urban heat island effect, increased longevity of roofing membranes, reduction in noise and air pollution, and improved aesthetics. Plants on rooftops are more susceptible to extremes in temperature and drought due to their shallow substrate and elevation above ground. Because of these unfavorable growing conditions, plant selection and season of establishment are critical. The major objective of this study was to quantify the effect of substrate depth and planting season on successful establishment of plugs of Sedum species on green roofs. Plugs of nine species of Sedum were planted in East Lansing, MI, in autumn (September 20, 2004) or spring (June 8, 2005) and then evaluated for survival on June 1, 2005, and June 1, 2006, respectively. Overall, spring planting exhibited superior survival rates (81%) compared to autumn (23%) across substrate depths. Sedum cauticola ‘Lidakense’, S. floriferum, and S. sexangulare were not affected by season of planting. Sedum cauticola barely survived at any substrate depth or planting season, whereas the latter two exhibited nearly 100% survival regardless of planting season. All other species had superior survival percentages when planted during spring.

scholarly journals Using natural fibre insulators on green roofs: some considerations

2020 ◽  
Vol 197 ◽  
pp. 02015
Author(s):  
Kristian Fabbri ◽  
Fabrizio Barbieri ◽  
Francesca Merli
Keyword(s):  
Thermal Performance ◽  
Green Roofs ◽  
Natural Fibre ◽  
Zero Energy ◽  
Insulating Material ◽  
Zero Energy Building ◽  
Synthetic Materials ◽  
Hygrothermal Behavior ◽  
Coconut Fibre ◽  
New Buildings

This study focuses on the application of coconut fibre insulators, an insulating material rarely utilized in the Mediterranean context. Despite its undoubted thermal performance, some queries are related with of his thermo-hygrometric behavior. More precisely, during the use of coconut for covering building for realizing green roofs, which represent a technological solution often adopted in the case of sustainable buildings or nearly zero energy building. Green roofs represent a valid constructive solution with high thermal performances, adopted in existing and new buildings. This paper investigates the thermo-hygrometric behavior of the concrete and Cross Laminated Timbre slabs, insulated with coconut fibreboards (CF) such as an alternative synthetic insulator, referred to a series of different green roofs scenarios. The results show that coconut fibre insulations are equally comparable to natural and synthetic materials. Therefore, coconut fibre could represent a good chance for realization of green roof having high thermal performance and hygrothermal behavior in the same time. This material could be an alternative solution to the normal synthetic materials actually used, in a perspective of sustainable architecture.

scholarly journals Optimization of Energy Consumption in Net-Zero Energy Buildings with Increasing Thermal Comfort of Occupants

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Mohsen Mahdavi Adeli ◽  
Said Farahat ◽  
Faramarz Sarhaddi
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
General Definition ◽  
Zero Energy ◽  
Zero Energy Building ◽  
Net Zero Energy ◽  
Net Zero Energy Building ◽  
Net Zero ◽  
Net Zero Energy Buildings ◽  
Zero Energy Buildings

Residential and commercial buildings consume approximately 60% of the world’s electricity. It is almost impossible to provide a general definition of thermal comfort, because the feeling of thermal comfort is affected by varying preferences and specific traits of the population living in different climate zones. Considering that no studies have been conducted on thermal satisfaction of net-zero energy buildings prior to this date, one of the objectives of the present study is to draw a comparison between the thermal parameters for evaluation of thermal comfort of a net-zero energy building occupants. In so doing, the given building for this study is first optimized for the target parameters of thermal comfort and energy consumption, and, hence, a net-zero energy building is formed. Subsequent to obtaining the acceptable thermal comfort range, the computational analyses required to determine the temperature for thermal comfort are carried out using the Computational Fluid Dynamics (CFD) model. The findings of this study demonstrate that to reach net-zero energy buildings, solar energy alone is not able to supply the energy consumption of buildings and other types of energy should also be used. Furthermore, it is observed that optimum thermal comfort is achieved in moderate seasons.

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