Infrastructure Engineering - Research Publications
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ItemSensitivity analysis on energy performance, thermal and visual discomfort of a prefabricated house in six climate zones in Australia(ELSEVIER SCI LTD, 2021-09-15)In prefabricated buildings distinctive construction process and lightweight components affect design strategies and consequences. Therefore, to create more sustainable prefabricated buildings, it is important to understand the effects of their envelope parameters on energy performance and indoor environmental quality. Although previous research have investigated the effects of envelope on energy and indoor comfort outputs, the parameters of lightweight prefabricated envelope are not thoroughly considered. This article quantifies the effects of building envelope parameters on the energy use, thermal comfort and daylighting levels of a prefabricated house built in Australia. A building simulation model was developed and validated by comparing predicted with measured indoor temperatures of the house. The baseline performance for evaluation of energy consumption, thermal discomfort hours and daylight unsatisfied hours were carried out using Transient System Simulation (TRNSYS) tool. Series of regression-based sensitivity analyses (SAs) to identify the most sensitive parameters were conducted by coupling TRNSYS, jEPlus and SimLab. Applications in six climate zones were investigated. The important focus areas found by SA in each climate and their corresponding design responses can be applied across ranges of prefabricated building projects if built in similar climatic conditions. SA results revealed window glazing and shading among the most influential parameters on all targeted performance outputs. The relationship between sensitivity levels to energy consumption and degree days indicated that the type of window has a higher impact on the reduction of energy use in the cooling dominated climates while insulation of wall was found a more effective strategy in heating-dominated climates.
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ItemMulti-objective optimisations of envelope components for a prefabricated house in six climate zones(Elsevier, 2021-01-15)The ever-increasing attention towards implementation of environmentally sustainable buildings necessitates the predictions of energy consumption and indoor environmental quality (IEQ) during early design stages. Prefabrication of buildings changes the construction process and components which affects building performance. Better understanding the effects of envelope components on energy performance and IEQ will inform design decisions leading to the creation of more sustainable buildings. In this article multi-objective optimisations of building envelope were carried out by coupling TRNSYS (Transient System Simulation Tool) and jEPlus + EA (EnergyPlus simulation manager for parametrics + Evolutionary Algorithms). The objective functions to be minimised were thermal discomfort hours (TDH), daylight unsatisfied hours (DUH) and life cycle costs (LCC) while maintaining acceptable sound transmission levels and indoor air quality. The decision variables were envelope components of a prefabricated house. Applications for six different climate zones corresponding to eight locations in Australia were investigated. The optimal solution sets were unique for each climate zone. The optimal solutions achieved 27–31% savings in LCC compared to the baseline. The reductions for TDH varied from 6% to 55% among the locations. As a result of trade-offs, the selected compromised solutions in each climate could achieve better reductions for either TDH, LCC or both.
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ItemNo Preview AvailableDataset on baseline performance and sensitivity analysis of a prefabricated house in six climate zones in Australia( 2020-11-26)This dataset includes the results of baseline performance evaluation and sensitivity analysis of a prefabricated house in six climate zones in Australia. The performance parameters investigated are monthly heating loads, monthly cooling loads, monthly thermal discomfort hours (TDHs) and monthly daylight unsatisfied hours (DUHs) of the living room, study room, and rumpus room in the prefabricated house.
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ItemNo Preview AvailableDataset on validation of TRNSYS building model for a prefabricated house built in Australia( 2020-11-26)This dataset includes data from the validation of TRNSYS building model for a prefabricated house built in Australia. The simulated indoor temperatures were compared with the measured ones in Melbourne. The comparison was carried out for the period between 19:00:00 on 31 March 2018 and 00:00:00 on 2 April 2018. Coefficient of determination (R²), Root Mean Square Error (RMSE), Mean Bias Error (MBE), Mean Absolute Error (MAE), and Correlation Coefficient (CC) were applied for quantification of the agreement between simulated and measured temperatures.
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ItemDataset on thermal properties, sound reductions, TVOC emissions, and costs of envelope components for prefabricated buildings in Australia (Version 2)( 2020-07-18)The data included in the dataset are related to prefabricated building components and their specifications. The specification provided are component type, material, thickness, density, thermal conductivity, specific heat, sound reduction index, total volatile organic compounds (TVOC) emissions and costs in various locations of Australia. The components that are included in this dataset are wall cladding, wall core, interior wall lining, insulation, roof cladding, floor covers and glazing. The authors attempted to cover most of the available component types and their available thicknesses. However, the authors acknowledge that due customisability of these products, other variations of the materials and their dimensions may have not been mentioned in the dataset. For some materials the specifications related to certain properties could net be accessed. Therefore, this dataset is designed to be open for updates and further development in the future. The dataset has been used in sets of building envelope design optimisation practices as input parameters.
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ItemDataset on thermal properties, sound reductions, TVOC emissions, and costs of envelope components for prefabricated buildings in Australia (Version 1)( 2020-04-04)This data article includes the common envelope components for prefabricated buildings in Australia. The thermal properties, sound reductions, total volatile organic compound emission rates and the cost data are included in this dataset. The material types and their available thicknesses were collected from commercially available standardised construction components. This data set can be used for building energy and indoor environmental quality performance evaluations. The cost data can be used for estimating the initial cost of building envelope. By further modification of data, they can also be used in Building Information Modelling (BIM) tools.
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ItemNo Preview AvailableA pilot study on users’ IEQ perceptions in a residential aged care facility in Melbourne(RMIT, 2018-11-29)The aged population in Australia is expanding rapidly. To cater for the Australia’s ageing population, there is a significant increase in demand for aged care facilities over the coming decades. The indoor environmental quality (IEQ) affects users’ physical health and psychological wellbeing. However, systematic research on the relationship between users’ perceptions and IEQ of aged care facilities has yet to be developed. In this pilot study, a residential aged care facility in Melbourne was selected as a case study for investigating the differences between the measured IEQ data and the users’ perceived individual comfort. A questionnaire survey was conducted to collect the perceptions of users on IEQ. Environmental sensors which enable web-based data monitoring were deployed. The measured data were then analysed together with the questionnaire survey results for drawing a comparison with the users’ perceptions. It was found that the measurements by environmental sensors are realistic and the survey questionnaires are appropriate for the study. For the future surveys, the language barrier needs to be considered for non-English speakers.
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ItemSensitivity analysis of building envelope parameters affecting thermal comfort(ZEMCH Network, 2018-01-29)The ever-increasing attention towards implementation of environmentally sustainable building design approaches necessitates the prediction of indoor environmental quality (IEQ) during design stage. Building performance simulation tools are able to predict key performance indices of buildings including IEQ. Among different aspects of IEQ, thermal comfort has been reported as one of the important aspects for occupants. It is necessary to understand the effects of design parameters on the performance of building in order to provide acceptable thermal comfort levels. However, due to the possibility of various design strategies, the selection of the most appropriate combination is a challenging task. Thus, the determination of effective parameters is of great importance in order to streamline the design process. The design parameters related to building envelope are among the most important items that have major influence on building thermal performance. Although prefabrication offers several benefits in terms of saving on-site time, saving money and better waste management, it affects envelope thermal performance due to introduction of lightweight components. While there is a body of research reporting the effects of passive strategies on building thermal performance, the influence of lightweight prefabricated envelope components is not well-documented in the current literature. This paper aims to perform a sensitivity analysis (SA) to identify the relative importance of major building envelope design parameters affecting thermal comfort of a prefabricated house in Melbourne, Australia. The envelope parameters investigated are: infiltration rate, solar heat gain coefficients and sizes of windows, and thermal resistance of insulation for exterior walls, floor and roof. The ranges of these parameters are based on the building components particularly used by prefabrication building industry in Australia. A typical three-bedroom prefabricated house in Melbourne was considered and the results of the SA are presented.
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ItemExploring demands for mass customised prefabricated houses in Brazil(ZEMCH Network, 2018-01-29)Housing shortage has been a challenge faced by many countries around the world. In Brazil, the housing supply capacity was less than demand by about 5.4 million dwellings in 2011. To address this shortfall, the Brazilian government launched ‘Programa Minha Casa Minha Vida’ (My House, My Life Program) in 2009 with the aim of reducing housing shortage. The program was divided into three development stages, the first and second stages of the program were completed in 2014 and 2016, respectively. The third stage is now ongoing, a grand total of 4.6 million dwellings are expected to be delivered at the completion by the end of 2018. However, there is significant lack of information on reliable housing demand and supply predictions for the coming years in Curitiba. In addition, the consumers’ feedback from first and second development stages showed that lack of choice and design customisability have been an issue. Therefore, quantifying housing demand in Curitiba is extremely important for planning purposes and better houses. Mass customised prefabricated houses have enormous potential to deliver high-quality in large scale with shorter time by providing options for the consumers. The aim of this study is to develop a housing demand model of mass customised houses for the city of Curitiba. The potential for future mass customisation in Curitiba is explored as the demand of various house sizes are predicted up to 2025. Based on the Brazilian Census data from 2010, population profiles and diversity of family’s structures are used as influencing parameters in the model. The outcome of the proposed model can be used as guideline or public policy for delivering appropriate mass customised houses which would fit future needs and desires of people. The predicted results show substantial reduction in size of the family living at the same dwelling, which will certainly impact on the future of the housing market. It was interpreted that there is a need of more compact one and two-bedroom dwellings, reducing the demand of four-bedroom dwellings.
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ItemComparing mixing ventilation and displacement ventilation in university classrooms(ZEMCH Network, 2018-01-29)There are two main types of mechanical ventilation systems: the mixing ventilation (MV) and the displacement ventilation (DV). The aim of this work is to compare their performance in terms of ventilation efficiency, air temperature, relative humidity, size-resolved particle concentrations, carbon dioxide (CO2) concentrations, and energy consumption. We performed a field investigation in two side-by-side classrooms installed with the two different ventilation systems. The energy consumptions were measured by i) a heat meter to measure the energy extracted by chilled water supplied, and ii) a power analyser to measure energy consumed by the ventilation fan. We also monitor indoor air dry bulb temperature, relative humidity, and CO2 concentrations in real-time for both rooms. It was found that the classroom with DV system consumed more energy. The unexpected high energy consumption can be attributable to the improved ventilation, CO2 and humidity control in DV room. Air temperature stratification were observed in DV room, but both room achieved similar volume-averaged temperate. We also found lower particle concentrations in both rooms compared to outdoor levels.