The Impact of Different Green Roofs Strategies on the Indoor Thermal Comfort with Special Reference to Cairo-Egypt

2014 ◽  
Vol 935 ◽  
pp. 38-43 ◽  
Author(s):  
Samar Mohamed Sheweka ◽  
Nourhan Magdy
Keyword(s):  
Thermal Comfort ◽  
Energy Savings ◽  
New Technology ◽  
Green Roof ◽  
Green Roofs ◽  
Green Buildings ◽  
Current Crisis ◽  
Indoor Thermal Comfort ◽  
Save Energy ◽  
The Impact

In present time, the environmental impact of green buildings on inner and outer climate has becomes more apparent. Green buildings are designed to reduce the overall impact of the built environment on human health and the natural environment. Recently, the popularity of green roof is growing in the context of urban landscaping because of its smaller footprint, aesthetic value, insulation benefits and heat island mitigation impact. Greenery roofs are considered to be a part of new technology that allows the use of alternative vegetation. This paper will explore the potentials of using green roofs as an integral part of the building process to save energy. This paper will introduce the energy crisis and will focus on the current crisis in Egypt and the global UHI effect. It will also identify the impact of vegetation as a sustainable approach for UHI mitigation and energy savings. After addressing green roof types, and their functional, and environmental aspects in general. The paper distills these different types to enhance thermal performance in terms of indoor thermal comfort and energy savings with the integration of PV cells within green roof design. This will be empirically examined by DesignBuilder and EnergyPlus Simulation, to explore the possibilities of improving indoor thermal comfort within the studied types. Then the paper will be concluded by a set of recommendations for buildings within Egypt’s climatic settings.

scholarly journals Building and Urban Cooling Performance Indexes of Wetted and Green Roofs—A Case Study under Current and Future Climates

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6192
Author(s):  
Madi Kaboré ◽  
Emmanuel Bozonnet ◽  
Patrick Salagnac
Keyword(s):  
Thermal Comfort ◽  
Emission Scenario ◽  
Green Roof ◽  
Heat Fluxes ◽  
Temperate Climate ◽  
Passive Cooling ◽  
Thermal Discomfort ◽  
Indoor Thermal Comfort ◽  
Performance Indexes ◽  
The Impact

We developed and studied key performance indexes and representations of energy simulation heat fluxes to evaluate the performance of the evaporative cooling process as a passive cooling technique for a commercial building typology. These performance indexes, related to indoor thermal comfort, energy consumption and their interactions with their surrounding environments, contribute to understanding the interactions between the urban climate and building for passive cooling integration. We compare the performance indexes for current and future climates (2080), according to the highest emission scenario A2 of the Special Report on Emission Scenario (SRES). Specific building models were adapted with both green roof and wetted roof techniques. The results show that summer thermal discomfort will increase due to climate change and could become as problematic as winter thermal discomfort in a temperate climate. Thanks to evapotranspiration phenomena, the sensible heat contribution of the building to the urban heat island (UHI) is reduced for both current and future climates with a green roof. The performance of the vegetative roof is related to the water content of the substrate. For wetted roofs, the impacts on heat transferred to the surrounding environment are higher for a Mediterranean climate (Marseille), which is warmer and drier than the Paris climate studied (current and future climates). The impact on indoor thermal comfort depends on building insulation, as demonstrated by parametric studies, with higher effects for wetted roofs.

scholarly journals Effect of insulation on indoor thermal comfort in a detached house with a floor heating system

2019 ◽  
Vol 111 ◽  
pp. 02049 ◽  
Author(s):  
Qianwen Guo ◽  
Ryozo Ooka ◽  
Wonseok Oh ◽  
Wonjun Choi ◽  
Doyun Lee
Keyword(s):  
Thermal Comfort ◽  
Thermal Insulation ◽  
Energy Savings ◽  
Residential Buildings ◽  
Insulation Material ◽  
Indoor Thermal Comfort ◽  
Detached House ◽  
The Impact ◽  
Floor Heating ◽  
Floor Temperature

Appropriate insulation materials, with unique physical properties and of moderate thickness, are essential for energy savings in residential buildings. However, the impact of thermal insulation on indoor thermal comfort with floor heating systems has not been studied extensively. In this study, simulations of a typical Japanese detached house were conducted with four different thicknesses of insulation material in the walls, ceiling, and floor to estimate the mean air temperature (MAT), mean radiant temperature (MRT), floor temperature, predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD). The results showed that increasing the thickness of thermal insulation increased the MAT and MRT by 1.4 – 4.0 ℃ and 1.3 – 4.4 ℃, respectively. Moreover, as the thickness of the thermal insulation increased, the floor temperature rose and exhibited smaller fluctuations. Finally, it was found that increasing the thickness of thermal insulation improved the indoor thermal comfort environment, as evidenced by an increase in the PMV from –1.0 to 0.3, and a decrease in the PPD from 25.1% to 9.5%.

scholarly journals How to Improve the Liveability in Cities: The Effect of Urban Morphology and Greening on Outdoor Thermal Comfort

2021 ◽  
Vol 65 (2-4) ◽  
pp. 361-370
Author(s):  
Guglielmina Mutani ◽  
Valeria Todeschi ◽  
Simone Beltramino
Keyword(s):  
Built Environment ◽  
Thermal Comfort ◽  
Energy Savings ◽  
Green Roofs ◽  
Urban Morphology ◽  
Outdoor Thermal Comfort ◽  
Water Runoff ◽  
Physiological Equivalent Temperature ◽  
The Impact ◽  
The City

Extensive and intensive green roofs and vegetated walls should be used to improve the livability in cities, especially in densely built-up context, in order to optimize their contribution on energy savings and greenhouse gas emissions, improving thermal comfort conditions and ensuring a greater storm-water runoff. The aim of this study is to evaluate the effect of urban morphology and to quantify the impact of green surfaces and plants on outdoor thermal comfort conditions. The analysis was applied to six neighborhoods in the city of Turin, identified as typical districts with different building geometries, urban contexts and green presence. The outdoor thermal comfort conditions were assessed calculating a set of indicators, such as the predicted mean vote and the physiological equivalent temperature, with the support of ENVI-met tool. Retrofit scenarios were hypothesized, and outdoor thermal comfort conditions were investigated before and after the installation of green roofs and vegetated areas. The result allowed to understand how thermal comfort vary, considering the building geometry, urban morphology, and green areas in different zones of the city of Turin. By analyzing neighborhoods, it is possible to identify the optimal built environment that ensure better thermal comfort conditions. These models and tools could support urban planners in defining the best measures to improve the liveability and quality in the built environment considering local constraints and the real characteristics of the territory or in designing new neighborhoods.

scholarly journals Green roofs in building retrofits: outdoor microclimate benefits and energy savings

2021 ◽  
Author(s):  
Melissa Ann Furukawa
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Energy Savings ◽  
Soil Depth ◽  
Green Roof ◽  
Green Roofs ◽  
Area Index ◽  
Heating And Cooling ◽  
Building Energy Analysis ◽  
The Impact

The impact of green roof retrofits on the local microclimate and energy consumption of a building is investigated. This research is based on a case study of Kerr Hall located on the Ryerson University campus in Toronto. The software ENVI-met is used to simulate the microclimate while EnergyPlus is used for the building energy analysis. Results indicate that increasing the leaf area index (LAI) of the green roof leads to increased cooling effect up to 0.4 degrees C during the day at pedestrian-level; however, more significant cooling is attained at the rooftop-level. The addition of the green roof reduced both the heating and cooling demands and improved indoor comfort levels. Energy demand reductions up to 3% were obtained with the green roof retrofits with the biggest contribution form from reduction in heating on the top floor. Increasing the soil depth had a larger impact on the energy consumption compared to increasing the LAI.

scholarly journals Green roofs in building retrofits: outdoor microclimate benefits and energy savings

2021 ◽  
Author(s):  
Melissa Ann Furukawa
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Energy Savings ◽  
Soil Depth ◽  
Green Roof ◽  
Green Roofs ◽  
Area Index ◽  
Heating And Cooling ◽  
Building Energy Analysis ◽  
The Impact

The impact of green roof retrofits on the local microclimate and energy consumption of a building is investigated. This research is based on a case study of Kerr Hall located on the Ryerson University campus in Toronto. The software ENVI-met is used to simulate the microclimate while EnergyPlus is used for the building energy analysis. Results indicate that increasing the leaf area index (LAI) of the green roof leads to increased cooling effect up to 0.4 degrees C during the day at pedestrian-level; however, more significant cooling is attained at the rooftop-level. The addition of the green roof reduced both the heating and cooling demands and improved indoor comfort levels. Energy demand reductions up to 3% were obtained with the green roof retrofits with the biggest contribution form from reduction in heating on the top floor. Increasing the soil depth had a larger impact on the energy consumption compared to increasing the LAI.

Investigating the Impact of Ornamental Plants Correlated with Indoor Thermal Comfort and Eco-Energy

2017 ◽  
Vol 8 (5) ◽  
pp. 221
Author(s):  
Sugiono Sugiono ◽  
Suluh E. Swara ◽  
Wisnu Wijanarko ◽  
Dwi H. Sulistyarini
Keyword(s):  
Thermal Comfort ◽  
Ornamental Plants ◽  
Indoor Thermal Comfort ◽  
The Impact

scholarly journals Seismic Performance of a Green Roof Structure

2021 ◽  
Vol 13 (8) ◽  
pp. 4278
Author(s):  
Svetlana Tam ◽  
Jenna Wong
Keyword(s):  
Green Roof ◽  
Time History ◽  
Green Roofs ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Roof Structure ◽  
Nonlinear Time History Analyses ◽  
Vegetated Roofs ◽  
Nonlinear Time History ◽  
The Impact

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.

scholarly journals Impacts on Indoor Thermal Comfort and Heating Energy Use in Hellenic Dwellings from Occupant Behavioral Reactions

2021 ◽  
Vol 11 (14) ◽  
pp. 6254
Author(s):  
Elena G. Dascalaki ◽  
Constantinos A. Balaras
Keyword(s):  
Thermal Comfort ◽  
Energy Use ◽  
Energy Savings ◽  
Local Heating ◽  
Economic Recession ◽  
Heating System ◽  
Building Stock ◽  
Heating Systems ◽  
Indoor Thermal Comfort ◽  
Energy Audits

In an effort to reduce the operational cost of their dwellings, occupants may even have to sacrifice their indoor thermal comfort conditions. Following the economic recession in Greece over recent years, homeowners have been forced to adapt their practices by shortening heating hours, lowering the indoor thermostat settings, isolating spaces that are not heated or even turning off their central heating system and using alternative local heating systems. This paper presents the results from over 100 occupant surveys using questionnaires and walk-through energy audits in Hellenic households that documented how occupants operated the heating systems in their dwellings and the resulting indoor thermal comfort conditions and actual energy use. The results indicate that the perceived winter thermal comfort conditions were satisfactory in only half of the dwellings, since the actual operating space heating periods averaged only 5 h (compared with the assumed 18 h in standard conditions), while less than half heated their entire dwellings and only a fifth maintained an indoor setpoint temperature of 20 °C, corresponding to standard comfort conditions. Mainstream energy conservation measures include system maintenance, switching to more efficient systems, reducing heat losses and installing controls. This information is then used to derive empirical adaptation factors for bridging the gap between the calculated and actual energy use, making more realistic estimates of the expected energy savings following building renovations, setting prudent targets for energy efficiency and developing effective plans toward a decarbonized building stock.

Prospects and restraints of green roofs for high-rise buildings in Sri Lanka

2019 ◽  
Vol 10 (2) ◽  
pp. 246-260
Author(s):  
Subaskar Charles ◽  
Herath Vidyaratne ◽  
Damithri Gayashini Melagoda
Keyword(s):  
Sri Lanka ◽  
Questionnaire Survey ◽  
Energy Savings ◽  
Green Roof ◽  
Green Roofs ◽  
Sri Lankan ◽  
Expert Interviews ◽  
Content Type ◽  
High Rise ◽  
The Government

Purpose Green roofs are acknowledged as a method to substitute greenery washed out by the urbanization. They provide many ecological and sustainable benefits of greenery; reduce the adverse effects of high-rise building constructions. Though this concept is more popular across many countries over the past few decades, still, implementation of this technology in Sri Lanka is new and scant. Hence, the purpose of this paper is to identify and analyze the potential of green roofs in high-rise buildings in Sri Lanka. Design/methodology/approach The data collection was conducted through expert interviews and questionnaire survey. Expert interviews were carried out to validate the prospects and restraints identified through literature review to the Sri Lankan context and analyzed using content analysis. Questionnaire survey identified the most significant prospects and restraints using descriptive statistics and paired sample t-test. Purposive sampling was used to select participants. Findings Reduction of air pollution, aesthetical appearance, thermal benefits and energy savings, reduction of an urban heat island effect, the addition of points in the green rating system are the top most significant prospects that need to be highlighted in promoting green roof systems in Sri Lankan high rises. Less space allocation on rooftops, lack of technical competence and lack of awareness and research are restraints that need most effective elimination strategies to encourage green roof systems. Originality/value The first identified and quantified prospects and restraints for green roof system in Sri Lankan high-rise buildings can be utilized by the government, donors, multi-lateral agencies to promote the sustainable development in Sri Lanka and this knowledge could be used in different scale awareness programs. The value of this paper is such that the paper discusses the links of green roofs with the other facets of sustainability. The new legal reforms and amendments in Sri Lanka could potentially be pending with findings of this study.

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