Thermal Performance Evaluation of Green Roofs in Warm Humid Climates: A Case of Residential Buildings in Madurai, India

2016 ◽  
Vol 692 ◽  
pp. 82-93 ◽  
Author(s):  
A Madhumathi ◽  
S. Radhakrishnan ◽  
R. Shanthipriya
Keyword(s):  
Thermal Properties ◽  
Thermal Performance ◽  
Energy Demand ◽  
Residential Buildings ◽  
Green Roof ◽  
Green Roofs ◽  
Outdoor Environment ◽  
Thermal Mass ◽  
Second Phase ◽  
Rapid Urbanization

Green roof application on real residential buildings in Tamilnadu, India is very limited and mostly concentrated in major cities mainly for visual purposes. There is not enough research has been conducted to boost up the benefits of green roof system in Warm and Humid weather in India. Green roofs have the potential to improve the thermal performance of a roofing system through shading, insulation, evapotranspiration and thermal mass, thus reducing a building’s energy demand for space conditioning. To quantify the thermal performance and energy efficiency of green roofs an experimental investigation was done in residential buildings of Madurai, Tamilnadu, India. This paper refers to the analysis of the thermal properties and indoor thermal performance study of the green roof. The investigation were implemented in two phases: during the first phase, extended surface, air temperature and relative humidity measurements were taken at the indoor and outdoor environment of the buildings where the green roof had installed and during the second phase of the study, the thermal properties of the green roof, as well as, the cooling potential were examined. Results showed vegetative roofs reduced heat gain compared to the white reflective roofs and conventional reinforced cement concrete due to the thermal mass, extra insulation, and evapo-transpiration associated with the vegetative roofing systems. The results also proved that green roofs provide acceptable indoor thermal performance with respect to the other conventional roofs while re-establishing the relationship between human and environment, which have been destroyed due to the rapid urbanization.

scholarly journals Effect of thermal mass of insulated and non-insulated walls on building thermal performance and potential energy saving

2021 ◽  
Vol 2042 (1) ◽  
pp. 012159
Author(s):  
M Haj Hussein ◽  
S Monna ◽  
A Juaidi ◽  
A Barlet ◽  
M Baba ◽  
...  
Keyword(s):  
Potential Energy ◽  
Thermal Insulation ◽  
Thermal Performance ◽  
Energy Demand ◽  
Thermal Environment ◽  
Residential Buildings ◽  
Thermal Mass ◽  
Climatic Zones ◽  
Performance Simulation ◽  
Heating And Cooling

Abstract The presented study aims to evaluate the effect of thermal mass in heavyweight construction in residential buildings in Palestine on indoor thermal environment using a building performance simulation tool. The most used residential building types, shapes and sizes were used as typical models for indoor environment performance simulation. The paper used a sensitivity analysis for four different scenarios according to the location of thermal insulation in the wall for two climatic zones, when no heating and cooling was used. The building material’s thermal properties, infiltration, activities, time schedule, electric lighting and glazing selection were based on onsite studies. The results show that the internal thermal mass of the studied buildings influences their thermal performance and future potential energy demand for heating and cooling. Buildings with insulation positioned on the outside, with high thermal mass and high thermal time constant showed the best thermal performance for different climatic zones, whereas buildings without thermal insulation or with insulation from the inside showed the worst thermal performance. The position of thermal insulation will affect potential energy demand for heating and cooling in the residential buildings.

scholarly journals COBERTURA E FACHADA VERDE:

2019 ◽  
Vol 8 (2) ◽  
pp. 89-100
Author(s):  
Thiago Youzi Kussaba Kayano ◽  
Nuria Perez Gallardo ◽  
Bruno César dos Santos ◽  
Mauricio Sanches Duarte Silva ◽  
Rafael Perussi ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Thermal Performance ◽  
Green Roof ◽  
Green Roofs ◽  
Sao Paulo ◽  
Test Cell ◽  
São Paulo ◽  
Control Test ◽  
Green Façade ◽  
Green Facade

Com a busca de alternativas para melhorar o conforto ambiental em ambientes construídos, os sistemas de fachadas e tetos verdes aparecem como uma opção para melhoria, em especial, do conforto térmico. Utilizando-se de um episódio climático representativo no mês de junho de 2016, analisou-se comparativamente o comportamento térmico de uma célula de teste com fachada e teto verde e uma célula de controle para avaliação do desempenho térmico em dia crítico experimental de frio. O experimento foi realizado no Centro de Recursos Hídricos e Estudos Ambientais (CRHEA) da Universidade de São Paulo (USP), em Itirapina-SP. Os resultados indicaram que a célula de teste com fachada e teto verde possui um melhor desempenho térmico em comparação à célula de controle. Palavras-chave: desempenho térmico, episódio climático representativo, comportamento térmico, fachada verde, cobertura verde. Abstract In searching for better thermal behavior alternatives in building environments green facade systems and green roofs emerge as an improvement option, particularly in thermal comfort. Using a representative climate episode to analyze the month of June of 2016 we studied the thermal performance of a green façade and green roof test cell and a control test cell in experimental critical cold day. The experiment was made in Water Resource and Environmental Studies Center (CRHEA) of University of São Paulo (USP), in Itirapina-SP. The results indicated the green wall and green roof test cell have a better thermal performance than control test cell. Keywords: Thermal performance, climatic representative episode, thermal behavior, green façade, green cover.

scholarly journals Water Sensitive Cities: integrated approach to enhance urban flood resilience in Parma (Northen Italy)

2021 ◽  
Author(s):  
Arianna Dada ◽  
Christian Urich ◽  
Michèle Pezzagno ◽  
Giovanna Grossi
Keyword(s):  
Water Management ◽  
Management Practices ◽  
Green Roofs ◽  
Integrated Approach ◽  
Second Phase ◽  
Urban Water ◽  
Flood Hazards ◽  
Rapid Urbanization ◽  
Water Sensitivity ◽  
Porous Pavement

<p>The climate change of the last half century is globally causing an increasingly in violent meteorological phenomena. Cities are experiencing the pressures of these phenomena and they are facing many challenges - economic, social, health and environmental.</p><p>Over the coming decades the population growth and the rapid urbanization will bring to a tumultuous growth of the cities that will become more and more vulnerable, especially to flood hazards.</p><p>In order to make our urban water systems more effective to these challenges new water management strategies must be developed. The complexity of this challenge calls for the integration of knowledge from different disciplines and collaborative approaches.</p><p>The concept of Water Sensitive Cities is one of the starting points for developing new techniques, strategies, policies, and tools to ensure a better liveability, sustainability, and resilience of the cities.</p><p>In this study, the DAnCE4Water model to promote the development of Water Sensitive Cities, was applied to Parma, an Italian town that faced serious water issues in the last years. Through the model the efficiency of new decentralized technologies, as green roofs and porous pavement, and their integration with the existing centralized technologies (sewerage), was estimated.</p><p>The first phase of the study concerned the analysis of the current state of the sewerage network and the relative critical issues. Flow rates and the amount of surface runoff were calculated using the SWMM modelling software.</p><p>In the second phase three hypothetical different scenarios were created by adopting different intervention strategies. The first scenario was created by using green roofs for a percentage of existing buildings in the urban area equal to 30%; the second scenario was created by adopting the porous pavement technology. For the third scenario, a possible urban development was simulated, with its consequent population, without adopting any flood risk mitigation strategy. A hydraulic study was carried out for each scenario highlighting the differences in terms of runoff formation and percentage of infiltration.</p><p>The integrated approach enables a city to test its current water management practices and policy, it helps cities to identify their short and long term goals to enhance water sensitivity, it gives a quantification of benefits and costs and it provides an estimate,  still in the design phase, of the effectiveness of possible strategies under different scenarios like climate changes, changes in the societal needs and urban changes by modelling the complex dynamics between societal system, urban environment and the urban water system.</p>

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 Determining Thermal Specifications for Vegetated GREEN Roofs in Moderate Winter Climates

2015 ◽  
Vol 9 (13) ◽  
pp. 208
Author(s):  
Christoph Maria Ravesloot
Keyword(s):  
Thermal Insulation ◽  
Thermal Performance ◽  
Energy Use ◽  
Green Roof ◽  
Green Roofs ◽  
Physical Parameters ◽  
Winter Climate ◽  
Theoretical Contribution ◽  
Winter Conditions ◽  
U Value

<p class="zhengwen">Because local weather conditions in moderate climates are changing constantly, heat transfer specifications of substrate and vegetation in vegetated green roofs also change accordingly. Nevertheless, it is assumed that vegetated green roofs can have a positive effect on the thermal performance of construction in winter conditions. Is there proof from scientific research and field testing for this assumption? To answer this question, research is conducted with the main research question: Which parameters defining thermal performance for vegetated green-roof construction for a moderate winter climate like that in the Netherlands can be determined from existing literature, and how do these parameters influence thermal performance? Literature research was executed on monitoring and testing of thermal specifications of vegetated green roofs. Models with physical parameters on vegetated green roofs were studied and compared. The first goal was to make a list of all physical parameters and corresponding variables valid in the Dutch moderate-winter climate. None of the models that were found in the literature seemed to cover all physical processes. These models use parameters and variables to calculate the overall u-value of substrate and vegetation. Nevertheless, one nearly complete model was used for a sensitivity test on variables. Maximum and minimum values of variables were calculated in the model to determine the influence on the outcome in terms of u-value. From this analysis, a distinction could be made between variables influencing the u-value strongly and other variables influencing the outcome weakly.</p><p class="zhengwen">The modelling showed that three variables were influencing the model calculations moderately strongly and therefore the thermal performance of the vegetated green-roof substrate and vegetation. These variables are not consistent with parameters modeling or calculating u-value in constructions. This finding means that contribution to thermal insulation by extensive vegetated green-roof substrate and vegetation in terms of u-value would be negligible. Only a small theoretical contribution to thermal insulation can be argued from weak variables. To be sure about this small theoretical contribution to the u-value of the roof construction, this u-value was used as input for energy-use calculations for residential buildings. These calculations show that such a small increase of the u-value leads to no visible reduction in energy use for heating in winter conditions. The contribution is negligible compared to the influence of the u-value from extra insulation under the roof.</p>For vegetated green roofs in such moderate winter climates as in the Netherlands, additional u-value will have to be proven specifically, because the modelling shows that, in general, no contribution to thermal insulation can be expected.

scholarly journals A Comparison of Energy and Thermal Performance of Rooftop Greenhouses and Green Roofs in Mediterranean Climate: A Hygrothermal Assessment in WUFI

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2030
Author(s):  
Mansoureh Gholami ◽  
Alberto Barbaresi ◽  
Patrizia Tassinari ◽  
Marco Bovo ◽  
Daniele Torreggiani
Keyword(s):  
Thermal Performance ◽  
Mediterranean Climate ◽  
Green Roof ◽  
Green Roofs ◽  
Energy Performance ◽  
Building Envelope ◽  
Considerable Proportion ◽  
Urban Context ◽  
Cooling Period ◽  
The Impact

In urban areas, a considerable proportion of energy demand is allocated to buildings. Since rooftops constitute one-fourth of all urban surfaces, an increasing amount of attention is paid to achieving the most efficient shapes and component designs compatible with every climate and urban context, for rooftops of varying sizes. In this study, three types of rooftop technologies, namely insulated, green roof, and rooftop greenhouse, are evaluated for energy and thermal performance using computer simulations. Water surface exposure, absorption, and intrusion are the three important factors in the calculation of hygrothermal models that impact energy consumption and building envelope performance; however, a few studies are specifically focused on providing realistic results in multi-dimensional hygrothermal models and the assessment of the impact of moisture in roofing solutions. This paper aims at evaluating the performance of three different roofing technologies through a two-dimensional hygrothermal simulation in software WUFI. To accomplish this, a precise localized microclimate model of a complex urban context on the scale of a neighborhood was employed to evaluate the cooling and heating loads of the buildings, the impact of the water content in the green roof on the thermal behavior of the roof surface, and the feasibility of designing a building with nearly zero cooling needs. A two-story building in the city center of Bologna, Italy is modelled. Simulation results have shown that during the cooling period, the performance of the designed rooftop greenhouse is the most effective by 50% reduction in cooling loads. Besides, the impact of moisture in green roofs has been detected as a negative factor for thermal and energy performance of the building in the Mediterranean climate. The results ultimately highlighted the capability of passively-designed rooftop greenhouses to create a building with nearly zero cooling needs.

Thermal Properties of Green Roof Media During Plant Establishment and Growth

2011 ◽  
Author(s):  
Geoffrey Frey ◽  
Ming Qu ◽  
Margaret K. Banks ◽  
Arthur Schwab ◽  
Keith A. Cherkauer
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
Root Growth ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermodynamic Model ◽  
Green Roof ◽  
Green Roofs ◽  
Plant Establishment ◽  
The Media

In order to ascertain the efficiency benefits of green roofs for buildings, a thermodynamic model must be created for the green roof. This work focuses on the thermal properties (conductivity and specific heat capacity) of several media and how they are affected by root growth within them. The results of this research will be used in creating more accurate thermodynamic green roof models. For this experiment, three repetitions of 16 different planting/media combinations were used to monitor the changing thermal properties of the media with environment changes; a focus being on root growth. This experiment shows that the conductance is probably affected by root propagation.

scholarly journals Carbon Sequestering and Green Roof Technology: A Benefit Cost Analysis

2018 ◽  
Vol 7 (1) ◽  
pp. 85
Author(s):  
Douglas Auld ◽  
Jeremy Wright
Keyword(s):  
Residential Buildings ◽  
Green Roof ◽  
Green Roofs ◽  
Private Benefits ◽  
Benefit Cost Analysis ◽  
Carbon Reduction ◽  
A Value ◽  
Carbon Sequestering ◽  
The Cost ◽  
Benefit Cost

The installation of a green roof on residential buildings affords the opportunity to sequester carbon from the atmosphere. The cost of incorporating green roofs in the construction of a family home or modifying an existing home is significant and the private benefits are rather small. Carbon reduction does have a value recognized by all levels of government in Canada. In this paper we calculate the cost of installing a green roof on a two vehicle garage in the Province of Ontario using current building costs. Utilizing data on the private costs and private benefits, the estimated NPV of a green roof over a 35 year period is negative. Once the value of carbon sequestering is introduced in the model, the NPV is positive, suggesting that subsidizing green roof construction is an efficient method in any government’s question to encourage a reduction in GHG emission.

scholarly journals Experimental Investigation of Green Roof Impact on Buildings Energy in Hot Climate

2020 ◽  
Vol 13 (2) ◽  
pp. 144-152
Author(s):  
Farah Abdulkadhum Malik ◽  
Alaa Liaq Hashem
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Energy Demand ◽  
High Surface ◽  
Green Roof ◽  
Green Roofs ◽  
Ambient Air ◽  
Maximum Temperature ◽  
Flux Flow ◽  
Zone Temperature

Green roofs are a layer that effectively working on blocks of solar radiation from entering the building's structure below partially. Its work as a passive cooling technique, and have the potential to reduce the high surface temperature of conventional roofs because of the soil thermal resistance, evapotranspiration, and several effects for foliage shading. This affects the heat flux flow of the roof that in turn influences the indoor thermal conditions and the building energy demand. The research goals are to test the influence of the green roof on reducing heat transfer to the interior of heavy structural buildings. The experimental part was done to examine the effect of the green roof and compare it with a standard roof under influence of ambient air temperature, solar radiation, and wind speed and test the effect of the green roof on reducing heat transfer inside the building. The model site was at the Diwanyah city (Latitude: 31.9868 and Longitude: 44.9215), the engineering college campus, Qadisiyah University. The experimental setup includes two cubicles, with equal internal volume values (163cm * 163cm * 105cm). The experimental results showed for the period 5-8 September 2019. The maximum zone temperature was 46.4 °C for traditional roof and 37.06 °C for the green roof at 3:24 p.m. The results showed that the maximum internal temperature was 46.97 °C and 36.42 °C for the traditional roof and green roof respectively at 3 p.m. Also,  the results for period 18-21 July 2019 noted that the zone temperature decreased by 7.5 °C and the maximum temperature of the internal traditional standard roof’s surface is 45.66 °C  and 37.41 °C for the green roof.

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