Browsing by Author "Perera, TANT"

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    Modelling of vertical greenery system with selected tropical plants in urban context to appraise plant thermal performance
    (Elsevier, 2021) Perera, TANT; Jayasinghe, GY; Halwatura, RU; Rupasinghe, HT
    Different growth parameters and thermal performances of selected plant species grown on vertical system modules in urban tropical climate have been investigated under the study. Further, outdoor thermal comfort simulation has been modeled by ENVI-met 4.4.5 to investigate the applicability of selected plant species in three different tropical conditions (Colombo Sethsiripaya administrative complex, Matara urban council building and Kandy Urban council building). Sample modular vertical green living wall panels were fabricated by using timber frames (60 × 40 × 5 cm) packed with cocopeat medium with a depth of 3.8 cm. Nine plant species; such as Desmodium triflorum, Roheo spathacea, Centella asiatica, Axonopus fissifoliu, Axonopus compressus, Elusine indica, Dieffenbachiae spp, Tectaria spp, and Bigonia spp were selected for the study. Plant survival percentages, plant height and leaf area index (LAI) were recorded for 8 weeks. Thermal performances were evaluated by considering temperatures at (a) 20 cm distance in front of the green wall, (b) substrate surface of the green wall modules and (c) inside the green wall compared to (d) adjacent bare wall (Control). The highest LAI was recorded from Roheo spp (3.99) followed by Axonopus f. (3.20) and Elusine spp (2.21). Axonopus f. exhibited the highest coverage on the living wall due to high LAI (>1). The highest temperature reduction (5.06 ◦C) was displayed by Axonopus f. compared to the other species as it covers large extent of the wall. The simulation study of the green walls developed with Axonopus f. signified a possible maximum temperature reduction of 2.07 ◦C, 3.29 ◦C and 2.03 ◦C in Colombo Sethsiripaya administrative complex, Matara urban council building and Kandy urban council building, respectively. Hence, modelling vertical greening with Axonopus f. can effectively enhance the thermal performance in urban context due to their LAI values and the thermal performances.
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    Towards greener cities; investigating the potentials of vertical greening in tropics as a design approach to create sustainable urban environments
    (Department of Architecture, University of Moratuwa, Sri Lanka, 2018-10-05) Rupasinghe, HT; Perera, TANT; Halwatura, RU; Wijesundara, J; Dayaratne, R
    The rapid population acceleration and urbanization pressurize the need of more living places leading to considerably high artificial constructed structures and comparatively less vegetation. Vertical greening is identified and implemented as an interesting integration in improving urban environmental quality and life standards. Energy saving, influencing biodiversity, noise attenuation and many more benefits are associated with the vertical greening. In Sri Lankan context the practice of vertical greening is still at an initial stage and the knowledge on the system is very limited. The paper presents the results of experimental design conducted to identify plant performance to select a plant species for vertical greening in local context. Twelve plant species were selected for the study. Plant health was rated for all plants using a 3 point scale. 1 = thriving, 2 = alive, but with signs of pest, disease or other stresses, 3 = dead. Plant height and leaf area were measured along with visual assessments of plant development stages and pest/disease incidence. Temperature reduction was measured for selected species. Inter-species variations were identified using one-way ANOVA followed by Tukey's pairwise comparison. In terms of actual performance, Roheo spathacea, Axonopus compressus, Ophiopogon japonicus, Axonopus fissifolius displayed the greatest survival and coverage on an extensive green wall. Highest LAI obtained from Roheo spathacea (3.99) followed by Axonopus compressus (0.99) over the trial period.