Browsing by Author "Jayasinghe, GY"

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item: Conference-Full-text
A Comparative analysis of operational energy by simulation study between modern buildings and adaptive reuse of historic buildings in Sri Lanka
(Department of Building Economics, 2024) Thirukumaran, N; Prabodani, MKM; Ranasinghe, SS; Jayasinghe, GY; Halwathura, RU; Sandanayake, YG; Waidyasekara, KGAS; Ranadewa, KATO; Chandanie, H
The adaptive reuse of buildings is emerging as a sustainable solution within the built environment, addressing global challenges like climate change and greenhouse gas emissions faced by the world's population. Opting to repurpose energy-efficient historic buildings during the operational phase instead of demolishing and constructing new structures is recognized as a protective mechanism for urban cultural heritage. The escalating operational energy consumption in the building sector poses direct and indirect environmental, economic, and social concerns for occupants. This study aimed to compare the operational energy efficiency of adaptive reuse historic buildings and modern structures, seeking to identify the most energy-efficient building type. Energy consumption patterns, especially for air conditioning and lighting in residential houses, were gathered and simulated using DesignBuilder software, considering building materials as variables in both the old and new phases of the buildings. Ten Dutch-era residential dwellings were selected, and a specific schedule was analysed for energy simulations. The average Energy Use Intensity (EUI) value for old buildings in the scheduled case was lower than the newly modelled buildings. The research concludes that old historic buildings are comparatively more energy-efficient and environmentally friendly than new buildings for operational use based on the building envelope in the selected study area.
item: Article-Full-text
Economical sustainability of vertical greeneries in tropical climate
(2023) Jayakody, GDC; Weerasinghe, KGNH; Jayasinghe, GY; Halwatura, RU
Vertical greening is recognized as a fascinating integration in enhancing urban environmental quality and living standards. A research series was initiated with the aim of implementing a Vertical Greening System (VGS) to achieve the maximum benefit in terms of thermal performance in Tropical Sri Lankan context. However, it is unknown if vertical greeneries are economically sustainable. The current research vacuum should be filled by assessing the economic benefit of various vertical greenery systems. This study assesses the economic value of direct green façade (DGF), indirect green façade (IGF), and living wall system (LWS) by considering installation and maintenance costs and energy-saving benefits during their life cycle, through a cost-benefit analysis (CBA). CBA is computed under three distinct circumstances: worst, middle, and best. Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PBP), and Benefit-Cost Ratio (BCR) are the four indicators used to calculate CBA. According to the study, DGF have positive NPVs for all scenarios and have acceptable IRR and BCR values with 6 years payback period. With best and middle scenarios, acceptable NPV, IRR and BCR values with 6–7 year payback period. Over three situations, LWS exhibits negative NPVs and indefinable IRR values. From An economic point of view, DGF and IGF are economically viable and living wall systems are not viable.
item: Article-Full-text
Evaluation of green infrastructure effects on tropical Sri Lankan urban context as an urban heat island adaptation strategy
(Elsevier, 2018) Herath, HMPIK; Halwatura, RU; Jayasinghe, GY
Incorporation of strategic green infrastructure into urban settings has a potential to mitigate climate change, urban heat island (UHI) effect, flood risk and subsequent increase in quality of human life in general. UHI induces through low surface albedo, building geometry and absence of greenery and it deteriorates the thermal comfort and well-being of city dwellers and occupants. This study examined the implication of urban green infrastructure on enhanced microclimatic condition in tropical urban perspective while evaluating the best suitable strategy by modeling a designated site with ENVI-met microclimatic software (V4). The calibration procedure of ENVI met has been undertaken through a real ground monitoring process and the software modeling was done for selected urban setting. The model was firstly validated by reconciliation of observed in-situ measurements with simulated values. R-squared (R2) values for three different surface types such as asphalt, cement and grass were 0.91, 0.96, 0.88 for near ground (0m) and 0.78, 0.81, 0.92 for 1.5 m, respectively. The parametric studies verified that ENVI-met model can be effectively utilized to improve urban micro-scale thermal conditions in tropical Sri Lanka. The numerical simulation model of ENVI-met was used to generate micro-climatic data for the selected area of Colombo metropolitan region with six greening design scenarios such as prevailing UHI condition (T1), trees in curbsides (T2), 100% green roofing (T3), 50% green roofing (T4), 50% green walls (T5) and a combination (T6) of above mentioned green strategies (trees in curbsides+ 50% green roofs+ 50% green walls). Temperature reductions obtained from all green strategies were compared with existing UHI (T1) scenario during peak temperature in given time. The temperature reductions accomplished by T2, T3, T4, T5 and T6 green infrastructure options compared to T1 were 1.87 °C, 1.76 °C, 1.79 °C, 1.86 °C and 1.90 °C, respectively. It can be concluded that strategic design of urban greenery can effectively enhance the urban environment and outdoor thermal comfort in tropical Sri Lanka.
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The impact of urban green infrastructure as a sustainable approach towards tropical micro-climatic changes and human thermal comfort
(Elsevier, 2018) Galagoda, RU; Jayasinghe, GY; Halwatura, RU; Rupasinghe, HT
Green infrastructures such as living walls are technological solutions to replace the declined greenery at urbanized environment and also reliable applications for thermal regulation in buildings through insulation effect and escalates the energy use efficiency. Thermal comfort and local climate are spatiotemporally variable. The existing research gap should be addressed by evaluating the performance of vertical green walls in tropical condition. In this study, thermal performance, relative humidity (RH) and CO2 concentration were quantified for basic three types of green infrastructures; such as (T1) living walls, (T2) indirect green façades and (T3) direct green façades located in Colombo metropolitan in Sri Lanka. An in-situ experimental study was conducted considering temperatures at 1 m and 0.1 m distance in front of the green walls, inside the foliage, air gap and external wall surface comparatively to adjacent bare wall control. Three case studies per green infrastructure within Colombo metropolitan area were purposively selected. Simultaneously, RH and CO2 concentration at 0.1 m in front of the green and bare walls were measured for the performance quantification. The internal thermal comfort simulation and occupants’ satisfaction questionnaire survey was executed to assess the green infrastructure performances. The study revealed that vertical greenery systems were highly effective on external wall surface temperature reductions at 1100 h–1500 h time zones. T1 and T2 accounted for superior temperature reduction in the range of 1.61 °C–1.72 °C through the façade relative to the distance than T3. Maximum temperature reduction compared to the bare wall control was obtained for the T1 (0.28 °C–8.0 °C) followed by T2 (1.34 °C–7.86 °C) and T3 (1.34 °C–6.64 °C). Averaged RH increment (1.6%–1.81%) and CO2 reduction (0.63%) occurred near green walls at day time compared to control. An average 28 °C simulated indoor temperature circumstantiate the indoor thermal comfort. 58% and 89.5% occupants’ were satisfied with thermal and visual comfort respectively, thus emphasizing façade greening as a sustainable approach on micro climatic changes and human thermal comfort.
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Investigation of rain surface erosion and bonding strength of different wall care putty materials along with different walling materials
(Elsevier, 2021) Gunawardana, SAA; Galkanda, HH; Halwatura, RU; Jayasinghe, GY
In tropical countries such as Sri Lanka, wall care putties are applied as primers in building constructions providing a smooth shield for the wall. This research study was conducted to investigate the durability performance in terms of rain surface erosion and the bonding strength by shear testing of different wall care putty materials along with walling materials. Four types of walling materials and ten types of wall care putty mixtures were selected. Accelerated erosion test and lap shear strength test were conducted and bond breaking patterns were examined. X-ray diffraction analysis was conducted to investigate the chemical compositions of putty mixtures. Results demonstrate that cement block walling material and putty C+10% cement wall care putty mixture have the highest bonding strength. Similarly, cement added putty mixtures showed higher durability and bonding strength than putties in their pure form.
item: Article-Full-text
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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Mold growth and moss growth on tropical walls
(Elsevier, 2018) Udawattha, C; Galkanda, H; Ariyarathne, IS; Jayasinghe, GY; Halwatura, R
The tropical climatic condition is the worst climate condition for building materials [1] [2] [3] [4]. Because, the tropics consist of rain, sun, high humid wind etc. [5] [6] [3]. The idea of the wall and roof are to protect human beings from these environmental constraints [4] [5] [6]. Hence, the capacity confronts those environmental constraints by the roof and wall are very important [7] [8] [9]. Not only environmental constraints but also there are other effects due to those environmental constraints such as weather degradation, scaling off the materials, natural decay, mold growth and moss growth. Molds can be found everywhere and can grow on any material in the presence of moisture. The growth of the mold is due to the pores. When the pores land on building materials they start to reproduce all over the material. Mold can be found in indoor climate as well as the outdoor climate. But the most dangerous mold can be found in indoor produced series of health problems due to a particle size of the mold [10]. Moss growth is subject to outdoor environments except in case of a water leak, which can be found in indoor climates. Moss growth is a common phenomenon in tropical climatic conditions. Moss growth is accelerated due to the rainy weather and stabilized by the materials property. For instant moss, brick is easily subjected to moss growth. The effect and the growth rate of mold and moss are not properly studied in tropical climatic conditions (See Table 1). Tropical climatic condition is the most favorable climate for mold and moss growth. Therefore it is essential to understand the causes of mold and moss growth in tropical walling Material.
item: Conference-Full-text
Prototyping a coating based on ancient technology: a case study in Sigiriya, Sri Lanka
(Department of Building Economics, 2024) Weerasekara, KMKD; Rathnayake, RMKM; Mendis, MS; Galabada, H; Jayasinghe, GY; Halwatura, RU; Sandanayake, YG; Waidyasekara, KGAS; Ranadewa, KATO; Chandanie, H
This paper presents a study on prototyping a coating based on ancient technology, specifically focusing on the techniques used in Sigiriya, an ancient rock fortress located in Sri Lanka. Sigiriya stands out for its remarkable paintings and innovative hydraulic systems, emblematic of an advanced ancient civilisation. Through an interdisciplinary approach merging archaeology, materials science, and chemistry, this research seeks to understand and replicate the coatings found on the Sigiriya paintings. By analysing the composition and properties of these coatings, a modern prototype was developed that mirrors the characteristics of the ancient coatings, offering insights into their longevity and preservation methods. The experimental emphasis of the research is on the production of a natural surface coating utilising wood apple gum and other natural extracts. The methods included coating formulation, application, and testing. There were five treatments in the study, each with different ratios (20%,40%,50%,60%, and 80%) of wood apple (Limonia acidissima) gum, Dorana (Dipterocarpus glandulosus) oil, sesame (Sesamum indicum)oil and Haldummala (Trachylobium verrucosum) mixes. This investigation explored the basic performance properties of coatings, looking closely at water resistance, viscosity, adhesion, pH levels, and aesthetic appeal. However, in treatment T1, the ratio of 20:80 of water: Dorana oil exhibited exceptional adhesion properties and displayed the maximum hardness level (8H). Some treatments also showcased promising indications of water resistance. The findings of this study hold the potential to significantly impact various sectors by providing eco-friendly alternatives, fostering innovation, creating cultural business prospects, and upholding traditional values.
item: Conference-Full-text
A simulation study on novel clay secondary walling system for indoor cooling: a performance assessment
(IEEE, 2022-07) Sriskandaraja, V; Rajapaksha, M; Halwathura, R; Jayasinghe, GY; Rathnayake, M; Adhikariwatte, V; Hemachandra, K
Climate change is a defining issue of our times. It has an influence on humans and the ecosystem because of variations in the earth’s temperature and rainfall patterns. As people spend the majority of their time indoors, changes in the climate can affect the quality of the outdoor air that seeps into their surroundings and raises the temperature of the air. Even though passive cooling options are available to mitigate this issue, they have been shown to be insufficient to meet the anticipated need. To achieve the desired level of comfort, residents of the building must use active cooling systems. The widely available active cooling systems are vividly demonstrated to be unsustainable and energy-intensive. Thus, this study aims to evaluate the use of energy-efficient and cost-effective techniques in a building by encouraging the use of natural materials, such as clay panels, to increase thermal mass and use hybrid ventilation techniques to reduce energy consumption. The results show the system’s effective and efficient configuration of 36 panels and 3 fans to create a comfortable indoor living environment.