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.

scholarly journals Impact of Green Roofs on Energy Demand for Cooling in Egyptian Buildings

2020 ◽  
Vol 12 (14) ◽  
pp. 5729 ◽  
Author(s):  
Ayman Ragab ◽  
Ahmed Abdelrady
Keyword(s):  
Thermal Conductivity ◽  
Energy Consumption ◽  
Energy Demand ◽  
Soil Depth ◽  
Green Roof ◽  
Green Roofs ◽  
Climatic Regions ◽  
Reduce Energy Consumption ◽  
The Impact ◽  
Reducing Energy

Energy consumption for cooling purposes has increased significantly in recent years, mainly due to population growth, urbanization, and climate change consequences. The situation can be mitigated by passive climate solutions to reduce energy consumption in buildings. This study investigated the effectiveness of the green roof concept in reducing energy demand for cooling in different climatic regions. The impact of several types of green roofing of varying thermal conductivity and soil depth on energy consumption for cooling school buildings in Egypt was examined. In a co-simulation approach, the efficiency of the proposed green roof types was evaluated using the Design-Builder software, and a cost analysis was performed for the best options. The results showed that the proposed green roof types saved between 31.61 and 39.74% of energy, on average. A green roof featuring a roof soil depth of 0.1 m and 0.9 W/m-K thermal conductivity exhibited higher efficiency in reducing energy than the other options tested. The decrease in air temperature due to green roofs in hot arid areas, which exceeded an average of 4 °C, was greater than that in other regions that were not as hot. In conclusion, green roofs were shown to be efficient in reducing energy consumption as compared with traditional roofs, especially in hot arid climates.

scholarly journals Modeling the Effect of Green Roof Systems and Photovoltaic Panels for Building Energy Savings to Mitigate Climate Change

2020 ◽  
Vol 12 (15) ◽  
pp. 2402 ◽  
Author(s):  
Yuanfan Zheng ◽  
Qihao Weng
Keyword(s):  
Climate Change ◽  
Energy Demand ◽  
Energy Savings ◽  
Soil Depth ◽  
Green Roofs ◽  
Building Energy ◽  
Positive Energy ◽  
Solar Photovoltaic ◽  
Area Index ◽  
Pv Systems

Green roofs and rooftop solar photovoltaic (PV) systems are two popular mitigation strategies to reduce the net building energy demand and ease urban heat island (UHI) effect. This research tested the potential mitigation effects of green roofs and solar photovoltaic (PV) systems on increased buildings energy demand caused by climate change in Los Angeles County, California, USA. The mitigation effects were assessed based on selected buildings that were predicted to be more vulnerable to climate change. EnergyPlus software was used to simulate hourly building energy consumption with the proper settings of PV-green roofs. All buildings with green roofs showed positive energy savings with regard to total energy and electricity. The savings caused by green roofs were positively correlated with three key parameters: Leaf Area Index (LAI), soil depth, and irrigation saturation percentage. Moreover, the majority of the electricity-saving benefits from green roofs were found in the Heating, Ventilation, and Cooling (HVAC) systems. In addition, this study found that green roofs have different energy-saving abilities on different types of buildings with different technologies, which has received little attention in previous studies.

scholarly journals Parametric simulation study for green roof retrofit over high performance solar house prototype “EFdeN Signature”

2019 ◽  
Vol 111 ◽  
pp. 04012
Author(s):  
Mihai BAICEANU ◽  
Tiberiu CATALINA
Keyword(s):  
Energy Demand ◽  
High Performance ◽  
Energy Savings ◽  
High Efficiency ◽  
Green Roof ◽  
Green Roofs ◽  
Area Index ◽  
Roof System ◽  
Low Efficiency ◽  
Solar House

The advantages of green roofs are well documented, ranging from heat island reduction, thermal comfort, air quality, stormwater management and energy savings for buildings. However, it has been shown that green roof retrofits are more effective in old, low efficiency buildings. This paper studies the possibility of retrofitting a high efficiency solar house with a green roof system being partially shaded, optimising its characteristics by means of parametric simulation. The input variables of the green roof system are: growth medium thickness, LAI (leaf area index) and height of plants. The output variables by which the different green roof systems are compared are: annual energy demand for heating and for cooling. The study concluded that the average reductions of energy consumption when retrofitting an efficient building with an extensive green roof are of 1.01% for heating and 4.61% for cooling, but optimising parameters (low LAI in winter, high LAI and height of plants in summer) can get reductions to 1.55% for cooling and 5.95% for cooling.

The impact of technology on architecture in Iran with focus on saving in energy consumption

2015 ◽  
Vol 16 (SE) ◽  
pp. 97-103
Author(s):  
Allah Bakhsh Kavoosi ◽  
Shahin Heidari ◽  
Hamed Mazaherian
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Industrial Revolution ◽  
Demand Prediction ◽  
Interior Spaces ◽  
Heating And Cooling ◽  
Impact Of Technology ◽  
Contemporary Architecture ◽  
The Impact ◽  
The Given

Growth and development of technology caused enormous transformation and change in the world after Industrial Revolution. The contemporary human has prepared the platform for their realization in many activities that the humans were unable to do it in the past time and struck the dream of their realization in their mind so that today doing many of those activities have been apparently practical by human. This accelerating growth accompanied with consuming a lot of energy where with respect to restriction of the given existing resources, it created energy crises. On the other hand, along with growth in industry and requirement for manpower and immigration from village to city and basic architectural changes in houses, which have emerged due to change in social structure it has led to change in lifestyle and type and quantity of consuming energy in contemporary architecture. Inter alia, with increase in human’s capability, cooling and heating and acoustic and lighting technologies were also changed in architecture and using mechanical system was replaced by traditional systems. Application of modern systems, which resulted from growth of industry and development of technology and it unfortunately, caused further manipulation in nature and destruction of it by human in addition to improving capability and potential of human’s creativity. With respect to growth of population and further need for housing and tendency to the dependent heating and cooling systems to them in this article we may notice that the housing is assumed as the greatest consumer of energy to create balance among the exterior and interior spaces in line with creating welfare conditions for heating and cooling and lighting. The tables of energy demand prediction in Iran show that these costs and energy consumption will be dubbed with energy control smart management in architecture.

scholarly journals Is Smart Growth a smart adaptation strategy?: Examining Ontario's proposed growth under climate change

2004 ◽  
Vol 71 (424-426) ◽  
pp. 57-62
Author(s):  
Brad Bass
Keyword(s):  
Climate Change ◽  
Energy Consumption ◽  
Urban Areas ◽  
Green Roof ◽  
Smart Growth ◽  
Green Roofs ◽  
Adaptation Strategy ◽  
University Of Toronto ◽  
Conducting Research ◽  
The Impact

The author is a member of Environment Canada's Adaptation and Impact Research Group, located in the Centre for Environment at the University of Toronto. His primary research interests include the use of ecological technologies in adapting urban areas to atmospheric change, the impacts of climate change on the energy sector, and the characteristics of adaptable systems. His current work on ecological technologies includes green roofs, vertical gardens and living machines. Dr Bass has been involved in two major projects, in Ottawa and Toronto, to evaluate the impact of green roofs on the urban heat island, energy consumption, stormwater runoff and water quality. Currently, Dr Bass is conducting research on integrating green roof infrastructure with other vegetation strategies at a community scale, simulating the impact of a green roof on the energy consumption of individual buildings.

scholarly journals Green Roofs as Effective Tools for Improving the Indoor Comfort Levels of Buildings—An Application to a Case Study in Sicily

2020 ◽  
Vol 10 (3) ◽  
pp. 893 ◽  
Author(s):  
Laura Cirrincione ◽  
Maria La Gennusa ◽  
Giorgia Peri ◽  
Gianfranco Rizzo ◽  
Gianluca Scaccianoce ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Electric Energy ◽  
Simulation Models ◽  
Green Roofs ◽  
Energy Performance ◽  
Comfort Levels ◽  
Indoor Comfort ◽  
The Impact

In the line of pursuing better energy efficiency in human activities that would result in a more sustainable utilization of resources, the building sector plays a relevant role, being responsible for almost 40% of both energy consumption and the release of pollutant substances in the atmosphere. For this purpose, techniques aimed at improving the energy performances of buildings’ envelopes are of paramount importance. Among them, green roofs are becoming increasingly popular due to their capability of reducing the (electric) energy needs for (summer) climatization of buildings, hence also positively affecting the indoor comfort levels for the occupants. Clearly, reliable tools for the modelling of these envelope components are needed, requiring the availability of suitable field data. Starting with the results of a case study designed to estimate how the adoption of green roofs on a Sicilian building could positively affect its energy performance, this paper shows the impact of this technology on indoor comfort and energy consumption, as well as on the reduction of direct and indirect CO2 emissions related to the climatization of the building. Specifically, the ceiling surface temperatures of some rooms located underneath six different types of green roofs were monitored. Subsequently, the obtained data were used as input for one of the most widely used simulation models, i.e., EnergyPlus, to evaluate the indoor comfort levels and the achievable energy demand savings of the building involved. From these field analyses, green roofs were shown to contribute to the mitigation of the indoor air temperatures, thus producing an improvement of the comfort conditions, especially in summer conditions, despite some worsening during transition periods seeming to arise.

scholarly journals Impact of Vegetation, Substrate, and Irrigation on the Energy Performance of Green Roofs in a Mediterranean Climate

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2016 ◽  
Author(s):  
Gomes ◽  
Silva ◽  
Valadas ◽  
Silva
Keyword(s):  
Mediterranean Climate ◽  
Energy Use ◽  
Soil Depth ◽  
Green Roof ◽  
Green Roofs ◽  
Energy Performance ◽  
Area Index ◽  
Vegetation Height ◽  
Energy Needs ◽  
Irrigation Levels

Green roof energy performance is still a challenging topic, namely in a Mediterranean climate since it depends on building characteristics, roof type, and also on climatic conditions. This paper evaluates green roof buildings’ energy needs and use in a Mediterranean climate. An experimentally calibrated numerical model was used to perform a parametric analysis and identify the influence of key parameters in heating and cooling energy needs, as well as annual energy use. The vegetation height, the soil depth, and LAI (leaf area index) were identified as the key parameters. The irrigation levels were also crucial for the energy performance of green roofs, particularly during the summer period and in a Mediterranean climate. Heating energy needs were mainly associated with soil depth due to higher thermal resistance, whereas cooling energy needs depended mostly on LAI, which influenced evapotranspiration and shading effects. A reduction of soil depth from 1.0 m to 0.1 m increased winter energy needs by up to 140%, while low values of LAI increased cooling energy needs up to 365%. Annual energy use in a Mediterranean climate showed a higher dependence on soil depth, with oscillations of up to 115%, followed by LAI and vegetation height. Finally, irrigation levels impacted the annual energy use more significantly for lower watering flow rates. Reductions of about 500% were obtained when changing watering flowrates from 0 mm/day to 6 mm/day in intensive green roofs. Since green roofs with native species expect low values of watering, this may increase their cooling energy needs.

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 Energy performance assessment and optimization of extensive green roofs in different climate zones of China

2020 ◽  
Vol 172 ◽  
pp. 16003
Author(s):  
Jiandong Ran ◽  
Zhenjing Yang ◽  
Ya Feng ◽  
Ke Xiong ◽  
Mingfang Tang
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Saving ◽  
Thermal Insulation ◽  
Green Roof ◽  
Green Roofs ◽  
Saving Rate ◽  
Area Index ◽  
Climate Zones ◽  
Extensive Green Roofs

There are many research and engineering projects on extensive green roofs, however, there is still no design guide for green roofs` climate energy efficiency, which limits the further promotion and usage of it, especially in China containing five climate zones. Taking different climate zones of China as examples, the verified building model is used in the DesignBuilder software, and 2-4 typical cities in each climate zone are selected, then combined the genetic algorithm (GA-Ⅱ) to optimize the energy efficiency of the building under green roofs. The results show that in all the cities studied in the five climatic zones, extensive green roofs are more energy efficient than ordinary thermal insulation roofs, and the energy saving rate is between 1-26.4%; except for the Nenjiang, which the energy is mainly used for heating, the cooling energy consumption is reduced and the heating energy consumption is increased after the optimized green roof is adopted in other cities; it is also found that the energy saving rate of the green roof with optimization has a high correlation with the total annual solar radiation value of the city. In addition, the energy efficiency optimization of green roofs in all cities shows that a larger leaf area index is more conducive to energy conservation; however, in southern China, it is not recommended to use a thermal insulation layer in the roof structural layer below the soil.

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