Influence of plant coverage on the total green roof energy balance and building energy consumption

Abstract This study quantifies the influence of green roof plant coverage on the building energy consumption and the substrate energy balance components. The analysis started with the implementation of a green roof model that accounts for the effects of plant coverage into the U.S. Department of Energy (DOE) building energy simulation program, EnergyPlus. Using the DOE reference building models, thirty different cases were simulated considering different green roof plant coverage, building type, and building age for two different climates. The results indicated that the green roof substrate surface temperature decreases with increasing plant coverage. This temperature decrease is primarily due to the decrease in the amount of absorbed solar radiation on the substrate surface and also an increase in the substrate surface evaporation. For the base-case simulation, due to the plant shading effects, the total daily received radiation at the bare-soil surface is 32% (6.2 kWh m−2) higher than that at the fully-covered green roof substrate surface. Furthermore, the annual cooling (heating) load decreases (increases) with the rate of 13 (0.88) kWh m−2 of plant coverage area. The aim of this study is to show the importance of considering plant coverage in green roof simulations and building energy demand predictions.

[1]  M. Santamouris,et al.  Analysis of the green roof thermal properties and investigation of its energy performance , 2001 .

[2]  M. Oppenheimer,et al.  The effectiveness of cool and green roofs as urban heat island mitigation strategies , 2014 .

[3]  Arthur Lyons,et al.  Materials for Architects and Builders , 2010 .

[4]  R. Belarbi,et al.  A comprehensive study of the impact of green roofs on building energy performance , 2012 .

[5]  Virginia Stovin,et al.  Green roofs; building energy savings and the potential for retrofit , 2010 .

[6]  Bing Liu,et al.  U.S. Department of Energy Commercial Reference Building Models of the National Building Stock , 2011 .

[7]  Virginia Stovin,et al.  Green Roofs - getting sustainable drainage off the ground , 2007 .

[8]  N. Wong,et al.  Investigation of thermal benefits of rooftop garden in the tropical environment , 2003 .

[9]  P. C. Tabares-Velasco,et al.  A heat transfer model for assessment of plant based roofing systems in summer conditions , 2012 .

[10]  Jelena Srebric,et al.  Validation of predictive heat and mass transfer green roof model with extensive green roof field data , 2012 .

[11]  J. Stocker,et al.  The effectiveness of retrofitted green and cool roofs at reducing overheating in a naturally ventilated office in London: Direct and indirect effects in current and future climates , 2014 .

[12]  R. Belarbi,et al.  Experimental and numerical investigation of urban street canyons to evaluate the impact of green roof inside and outside buildings , 2014 .

[13]  D. Raes,et al.  Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century , 2006 .

[14]  Jun Yang,et al.  Quantifying air pollution removal by green roofs in Chicago , 2008 .

[15]  Weimin Wang,et al.  Advanced Energy Retrofit Guide Retail Buildings , 2011 .

[16]  Jon Hand,et al.  CONTRASTING THE CAPABILITIES OF BUILDING ENERGY PERFORMANCE SIMULATION PROGRAMS , 2008 .

[17]  E. P. D. Barrio.  Analysis of the green roofs cooling potential in buildings , 1998 .

[18]  Jelena Srebric,et al.  Effects of plant and substrate selection on thermal performance of green roofs during the summer , 2014 .

[19]  L. Bengtsson,et al.  Runoff water quality from intensive and extensive vegetated roofs , 2009 .

[20]  David J. Sailor,et al.  A green roof model for building energy simulation programs , 2008 .

[21]  H. Akbari,et al.  Analyzing the land cover of an urban environment using high-resolution orthophotos , 2003 .

[22]  P. C. Tabares-Velasco,et al.  Experimental quantification of heat and mass transfer process through vegetated roof samples in a new laboratory setup , 2011 .

[23]  H. Takebayashi,et al.  Surface heat budget on green roof and high reflection roof for mitigation of urban heat island , 2007 .

[24]  W. G. Hansen.  How Accessibility Shapes Land Use , 1959 .

[25]  U. Berardi,et al.  State-of-the-art analysis of the environmental benefits of green roofs , 2014 .

[26]  Theodore G Theodosiou,et al.  Summer period analysis of the performance of a planted roof as a passive cooling technique , 2003 .

[27]  Youbin Zheng,et al.  Fertilizer Rate and Type Affect Sedum-vegetated Green Roof Mat Plant Performance and Leachate Nutrient Content , 2014 .