Weather effect on thermal and energy performance of an extensive tropical green roof

Jim, Chi Yung; Peng, Lilliana L.H.

doi:10.1016/j.ufug.2011.10.001

Cited by 126 publications

(53 citation statements)

References 28 publications

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“…Green roofs offer recreational areas to supplement the ground-level UGS stock. Moreover, they provide environmental and ecological benefits such as temperature cooling, air pollutant removal, noise reduction, storm water discharge reduction and water quality improvement, and wildlife habitats (Dunnett and Kingsbury 2004;Jim and Tsang 2011;Jim and Peng 2012).…”

Section: Ameliorate Pervasive Urban Soil Constraintsmentioning

confidence: 99%

Sustainable urban greening strategies for compact cities in developing and developed economies

Jim

2012

Urban Ecosyst

210

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Urban greening contributes notably to quality of life and ecosystem services in cities. Compact cities in developing and developed countries are commonly beset by greenspace deficit. Based on literature review supplemented by field studies in different cities, a sustainable urban greening strategy is proposed. Urban renewal and new developments without a greening vision could miss the opportunities to bring relief. The public and private sectors can join hands to insert plantable spaces into the urban fabric. Urban greenspaces (UGS) with good connectivity forming a green network to permeate the city constitute the hallmarks of a naturalistic design. Preservation and creation of natural areas with rich biodiversity offer a new dimension to UGS design. Greening benefits could be expressed in economic terms to complement conventional ecological-environmental emphasis. Outstanding trees could receive high-order conservation efforts, and trees in construction sites warrant enhanced protection. Tree transplanting demands an overhaul in concepts and skills. Improving roadside tree planting and maintenance offers a cost-effective way to upgrade the townscape. Ameliorating widespread soil limitations could remove a major hindrance to tree growth. Innovative ideas of development right transfer, street pedestrianization, river and canal revitalization, green roofs and green walls could mobilize hitherto underused plantable resources. Lacking appropriate institutional setup and scientific capability pose intractable bottlenecks. Innovative public policies and greening technologies are needed for sustained improvements. Amalgamating natural and social sciences in a multidisciplinary approach and reinforcing the link between science and public policies could overhaul greening.

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Section: Ameliorate Pervasive Urban Soil Constraintsmentioning

confidence: 99%

Sustainable urban greening strategies for compact cities in developing and developed economies

Jim

2012

Urban Ecosyst

210

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“…There is extensive bibliographic and scientific literature on this subject emphasizing the different positive purposes it may serve. These include, the reduction of annual energy consumptions in buildings related to both summer cooling [1][2][3][4] and winter heating [2,4], the contribution to the reduction of both greenhouse gas emissions [5] and urban canyon temperatures [4,[6][7][8], the management of atmospheric precipitation [9] and urban runoff problems [10], noise absorption [11,12], support of biodiversity, and the creation of new natural habitats [13,14].…”

Section: Introductionmentioning

confidence: 99%

Measurement of Thermal Properties of Growing Media for Green Roofs: Assessment of a Laboratory Procedure and Experimental Results

et al. 2017

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While the Italian standard UNI 11235:2015 establishes minimum performance criteria, the thermal resistance of the growing medium of green roofs is not included in national regulations. Instead, thermal transmittance limits for roofs are obtained by referring to other stratigraphic layers. In the absence of specific national and international standards for laboratory calculations of the thermal performance of growing media for green roofs, a multi-year laboratory testing campaign was carried out on 8 samples which aimed to define the thermal resistance reference values of growing media as a function of density and water content. Thermal conductivity varies between 0.046-0.179 W/mK for dry samples as a function of density and between 0.046-0.47 W/mK as a function of moisture content. Defining a reference method, laboratory tests and restitution of the output in performance curves, was based on 108 tests carried out according to and deviating from the standard based on both guarded hot plate and heat flow meter methods. The significance of the results has prompted researchers and industrial partners to engage in further investment and ongoing tests in this area, targeting the definition of a standard laboratory method to be presented worldwide.

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“…The multiple layers of the green-roof structure can protect building roofs from direct solar radiation in the summer, cutting heat flux entering the interior spaces and saving electrical energy for cooling. The evapotranspiration from vegetation and soil can cool the ambient air and improve microclimate, triggering "cool-island" effects [7,8]. The literature has generated extensive studies on green-roof thermal effects in various climatic contexts.…”

Section: Introductionmentioning

confidence: 99%

“…It has been widely reported that the UHI effect display notable seasonal and diurnal patterns with varying background weather parameters, such as radiation, humidity, temperature, and wind speed [37]. These weather factors also exert significant influence on the heat and water dynamics of green-roof systems [7,19]. Evaluation of the temporal variations of green-roof thermal performance with respect to weather effects enables a deep and comprehensive understanding of its role as a UHI mitigation measure.…”

Section: Introductionmentioning

confidence: 99%

Seasonal and Diurnal Thermal Performance of a Subtropical Extensive Green Roof: The Impacts of Background Weather Parameters

Peng

Jim

2015

Sustainability

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Most studies explored green-roof thermal effects on a few hot summer days based on short-term monitoring data. Few studies investigated the seasonal and diurnal patterns of thermal performance and associated weather effects. This research aims to address the following two questions: (1) how green-roof thermal performance varies with different season and time; and (2) to what extent can thermal performance be predicted by background weather parameters? A retrofitted extensive green roof was established on the top of a railway station in subtropical Hong Kong. Monitoring data covering a two-year period, one year before roof greening and one year after, were collected and analyzed. Results indicated notable seasonal and diurnal patterns of green-roof thermal performance. It exhibited cooling effects in spring, summer and fall, but warming effects in winter. The cooling effects were more pronounced in summer than spring and fall, on sunny days than rainy and cloudy days, and in nighttime than daytime. Air temperature, relative humidity, wind speed, solar radiation, and soil moisture could explain 83.6%-86% of the thermal effects' variation. The multiple-regression models based on the five weather variables established in this study provide an uncomplicated and direct approach to predict the thermal performance of similar extensive green roofs in subtropical areas. OPEN ACCESSSustainability 2015, 7 11099

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Weather effect on thermal and energy performance of an extensive tropical green roof

Cited by 126 publications

References 28 publications

Sustainable urban greening strategies for compact cities in developing and developed economies

Sustainable urban greening strategies for compact cities in developing and developed economies

Measurement of Thermal Properties of Growing Media for Green Roofs: Assessment of a Laboratory Procedure and Experimental Results

Seasonal and Diurnal Thermal Performance of a Subtropical Extensive Green Roof: The Impacts of Background Weather Parameters

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