Browsing by Author "Weerasinghe AS"

Now showing 1 - 6 of 6
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    Comparative Life-Cycle Cost (LCC) study of Green and Traditional Industrial Buildings in Sri Lanka
    (Elsevier, 2021) Weerasinghe AS; Ramachandra T; Rotimi JOB
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    Effects of green retrofits: A case of industrial manufacturing buildings in Sri Lanka
    (1/01/2019) Weerasinghe AS; Ramachandra T; Nawarathna A
    The impact of built environment on the global warming, greenhouse gas emissions and natural resources depletion is staggering. Consequently, existing built environment will have very high responsibility in dealing with global issues, unless the rate of green retrofitting is amplified. Existing buildings are accountable for 39% of energy use and 35% carbon dioxide emissions, whereas, green retrofitting can achieve 40%-60% energy saving, which contributes 20%-30% carbon emission reduction. Nevertheless, the building owners are less willing to pay for retrofits due to high initial cost and identifying the most cost-effective retrofits for a particular project is still a major challenge. The current study therefore analyses the costs and saving implications of various green retrofits incorporated into an industrial manufacturing building in Sri Lanka. The study used mixed methods in data collection where professionals involved in green retrofits industrial manufacturing buildings were interviewed to identify the green retrofit technologies implemented and the reasons for selection of those green retrofits and subsequently a detailed costs and saving potential analysis of green retrofits incorporated in the selected green retrofit certified industrial manufacturing building was performed using Net Present Value and Simple Payback Period. The analyses show that the use of retrofits related to energy, indoor environmental quality and water are at a significant level in industrial manufacturing buildings in Sri Lanka. Moreover, the implemented retrofit projects indicate the financial viability of green retrofits with positive net present values and simple payback period of less than 5 years. Considering the lifetime financial returns of those retrofits, each indicates significant benefits compared to initial investment. Therefore, the success of these actual retrofit scenarios would enable to identify the most appropriate retrofits based on the potential expenses and returns involved, and thereby assist building investors to incorporate most feasible retrofits into their existing buildings.
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    Environmental and socio-psychological drivers of building users’ behaviours: A case study of tertiary institutional offices in Auckland
    (Emerald Publishing, 2022) Weerasinghe AS; Rasheed EO; Rotimi JOB
    Purpose: Better identification of comfort preferences and occupant behaviour drivers is expected to improve buildings’ user-centred designs and energy operations. To understand the underline drivers of occupant behaviours in office buildings, this study aims to evaluate the inter-relationships among occupant energy behaviours, indoor environmental quality satisfaction, user control and social-psychological factors influencing occupant behaviours in New Zealand offices. Design/methodology/approach: Using an occupant perception survey, this study identifies the occupant behaviour patterns based on multi-domain comfort preferences. A case study was conducted in five office spaces of a university in Auckland, New Zealand. Data were collected from 52 occupants and analysed using descriptive and binary logistic regression analysis. Indoor environmental quality, user control, motivational, opportunity and ability factors were the independent variables considered. A model to predict the behaviours using environmental, building and social-psychological aspects was developed. Findings: The results showed that the primary sources of indoor environmental quality discomfort were related to thermal and air quality, while occupants’ indoor environmental quality satisfaction correlated with their comfort preferences. The outcomes emphasise how the connection between building systems and occupants’ comfort preferences affect the choice of occupant behaviours in offices. Also, the primary occupant behaviours were drinking hot and cold beverages, opening/closing windows and internal doors and adjusting clothing. The binary logistic regression analysis showed that occupants’ perceived user control satisfaction is the main driver for increasing window actions. No other independent variable showed a statistically significant association with other behaviours. Originality/value: This study adopted a novel approach to assess the combined effects of comfort preferences, occupant energy behaviours and various environmental, building and socio-psychological factors for modelling energy-saving behaviours in office buildings.
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    Implications of sustainable features on life-cycle costs of green buildings
    (1/09/2020) Weerasinghe AS; Ramachandra T
    The green buildings seem unattractive to developers who prioritize fast investment returns, due to costs attributed to implementing sustainable features and consequently, only 19% of existing buildings are certified for green, globally. Furthermore, green buildings are aimed at achieving a minimum sustainability level in certification. Therefore, the current study aims to investigate the significant sustainable features and the implications of those features on green buildings' life-cycle costs. The study involved a preliminary investigation to find the significant sustainable features implemented. Subsequently, two green buildings were carefully selected, and a detailed analysis was performed. The data relating to the green building construction, operation and maintenance costs were collected and analysed using Net Present Value. The features have varying degree of contribution to sustainability in terms of the achievement of allocated points in the rating system. The certified buildings have achieved over 75% of allocated points in terms of water efficiency and sustainable sites features, while the achievement level of other features is below average level. Further, highly achieved features are more economical in terms of their less contribution to construction and maintenance costs. On the other hand, the features with lower achievement in certification, contribute significantly to construction and maintenance costs, while providing higher savings during operation. Therefore, the current study recommends, green building investors to select the most suitable features for a given construction based on their respective contributions to the life-cycle cost of green buildings.
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    Occupants’ Decision-Making of Their Energy Behaviours in Office Environments: A Case of New Zealand
    (1/02/2023) Weerasinghe AS; Rasheed EO; Rotimi JOB
    Understanding how occupants behave and interact with building systems is vital to energy efficiency in buildings. The building occupants’ behaviours are complex and influenced by diverse factors. A deep understanding of the underlying environmental, contextual, social, and psychological factors is the first step of many in establishing the relationship between the indoor environment and occupants’ behaviours. The current study investigates the influence of occupants’ perceived indoor environmental comfort, the availability of control, and the social-psychological impacts on occupant behaviours in a New Zealand context. The data were collected through online surveys, and 99 office occupants responded. A machine learning technique was applied to identify the critical factors influencing the decision-making of occupant behaviours. Of the occupant behaviours considered in the study, adjusting windows, doors, shades and blinds, and drinking beverages were mostly practised (>70%) while adjusting lighting, personal fans, thermostats/heaters, and computers (40–70%) was moderately practised by occupants. The availability of specific user controls was the main predictor of most occupant behaviours, followed by social-psychological factors such as actual knowledge, perceived knowledge, behavioural interventions, subjective norms, organisational support, personal norms, attitudes, and perceived behavioural control. The indoor environmental parameters such as indoor temperature, indoor air quality, natural light, and inside noise were highlighted as most influential in decision-making for occupant behaviours. Additionally, the demographic factors: gender, work duration, days at work, and permanence/temporariness of workspace, were also impactful. Knowing the complexity of occupants’ decision-making with respect to their behaviours helps building managers use this sensitive information to enhance building energy performance and enable more energy feedback to the occupants to raise their awareness. Such information is helpful for creating an intelligent environmental control system loop with eco-feedback and establishing occupant-centric buildings or features.
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    Towards sustainable commercial buildings: An analysis of operation and maintenace (O&M) costs in Sri Lanka
    (Emerald Publishing Limited, 14/09/2020) Weerasinghe AS; Ramachandra T; Rotimi JOB
    Purpose Rising energy costs and increasing environmental concerns are catalysts for introducing sustainable design features in buildings. Incorporating sustainable design features in commercial buildings cannot be overstated because it could confer benefits to the investor (owners) and occupants. This study aims to develop a model that could aid in the prediction of operation and maintenance (O&M) costs from the knowledge of building-design variables. There is little evidence that design variables influence the O&M costs of buildings. Therefore, this study investigates the relationship between design variables and O&M costs in commercial buildings with the intent of developing a cost model for estimating O&M costs at the early design phase. Design/methodology/approach The study was approached quantitatively using a survey strategy. Data for the study were obtained from 30 randomly selected commercial buildings in the CBD in Colombo, Sri Lanka. Pareto's 80/20 rule, correlation and regression analysis were performed on the data to prove the statistical relationships between the buildings' O&M costs and their design variables. Findings The study found that 12 significant O&M costs elements contribute to about 82% of total O&M costs. Repairs and decoration had a strong correlation with building shape. Furthermore, the regression analysis found that O&M costs values were primarily dependent on the building size (the gross floor area and height of the buildings). The gross floor area and height handled over 73% of the variance in the O&M costs of commercial buildings in Sri Lanka. Originality/value These findings are a useful insight into the principles for design economies that could contribute to more sustainable commercial buildings.