Infrastructure Engineering - Research Publications

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    The carbon footprint of treating patients with septic shock in the intensive care unit
    McGain, F ; Burnham, J ; LAU, R ; Aye, L ; Kollef, MH ; McAlister, S (College of Intensive Care Medicine of Australia and New Zealand, 2018-12-01)
    OBJECTIVE: To use life cycle assessment to determine the environmental footprint of the care of patients with septic shock in the intensive care unit (ICU). DESIGN, SETTING AND PARTICIPANTS: Prospective, observational life cycle assessment examining the use of energy for heating, ventilation and air conditioning; lighting; machines; and all consumables and waste associated with treating ten patients with septic shock in the ICU at BarnesJewish Hospital, St. Louis, MO, United States (US-ICU) and ten patients at Footscray Hospital, Melbourne, Vic, Australia (Aus-ICU). MAIN OUTCOME MEASURES: Environmental footprint, particularly greenhouse gas emissions. RESULTS: Energy use per patient averaged 272 kWh/day for the US-ICU and 143 kWh/day for the Aus-ICU. The average daily amount of single-use materials per patient was 3.4 kg (range, 1.0-6.3 kg) for the US-ICU and 3.4 kg (range, 1.2-8.7 kg) for the Aus-ICU. The average daily particularly greenhouse gas emissions arising from treating patients in the US-ICU was 178 kg carbon dioxide equivalent (CO2-e) emissions (range, 165-228 kg CO2-e), while for the Aus-ICU the carbon footprint was 88 kg CO2-e (range, 77-107 kg CO2-e). Energy accounted for 155 kg CO2-e in the US-ICU (87%) and 67 kg CO2-e in the Aus-ICU (76%). The daily treatment of one patient with septic shock in the US-ICU was equivalent to the total daily carbon footprint of 3.5 Americans' CO2-e emissions, and for the Aus-ICU, it was equivalent to the emissions of 1.5 Australians. CONCLUSION: The carbon footprints of the ICUs were dominated by the energy use for heating, ventilation and air conditioning; consumables were relatively less important, with limited effect of intensity of patient care. There is large opportunity for reducing the ICUs' carbon footprint by improving the energy efficiency of buildings and increasing the use of renewable energy sources.
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    Applications of phase change materials in concrete for sustainable built environment: a review
    JAYALATH, A ; Mendis, PA ; Gammampila, GR ; Aye, L (ICSECM 2011, 2011)
    The fast economic development around the globe and high standards of living imposes an ever increasing demand for energy. As a prime consumer of world‟s material and energy resources building and construction industry has a great potential in developing new efficient and environmentally friendly materials to reduce energy consumptions in buildings. Thermal energy storage systems (TES) with Phase change materials (PCM) offer attractive means of improving the thermal mass and the thermal comfort within a building. PCMs are latent heat thermal storage (LHTS) materials with high energy storage density compared to conventional sensible heat storage materials. Concrete incorporating PCM improves the thermal mass of the building which reduces the space conditioning energy consumption and extreme temperature fluctuations within the building. The heat capacity and high density of concrete coupled with latent heat storage of PCM provides a novel energy saving concepts for sustainable built environment. Microencapsulation is a latest and advanced technology for incorporation of PCM in to concrete which creates finely dispersed PCMs with high surface area for greater amount of heat transfer. This paper reviews available literature on Phase change materials in concrete, its application and numerical modelling of composite concrete. However most of the existing TES systems have been explored with wallboards and plaster materials and comparatively a few researches have been done on TES systems using cementitious materials. Thus, there is a need for comprehensive experimental and analytical investigations on PCM applications with cementitious materials as the most widely used construction materials in buildings.
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    Application of nanomaterials in the sustainable built environment
    Gammampila, GRG ; Mendis, PAM ; Ngo, TDN ; Aye, LA ; JAYALATH, A ; RUPASINGHE, RAM (University of Moratuwa, 2010)
    Nanotechnology is widely regarded as one of the twenty-first century’s key technologies, and its economic importance is sharply on the rise. In the construction industry, nanomaterials has potentials that are already usable today, especially the functional characteristics such as increased tensile strength, self-cleaning capacity, fire resistance, and additives based on nano materials make common materials lighter, more permeable, and more resistant to wear. Nanomaterial are also considered extremely useful for roofs and facades in the built environment. They also expand design possibilities for interior and exterior rooms and spaces. Nano–insulating materials open up new possibilities for ecologically oriented sustainable infrastructure development. It has been demonstrated that nanotechnology has invented products with many unique characteristics which could significantly provide solutions current construction issues and may change the requirement and organization of construction process. This paper examines and documents applicable nanotechnology based products that can improve the sustainable development and overall competitiveness of the construction industry.
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    Application of nano insulation materials in the sustainable built environment
    Gammampila, GRG ; Mendis, PAM ; Ngo, TDN ; Aye, LA ; Herath, NCH (University of Moratuwa, 2010)
    Nanotechnology is widely being used in the built environment for its advantages in many improved engineering properties of the nano materials. Nano insulating materials open up new possibilities for ecologically oriented sustainable infrastructure development. The most widely used nano material in built environment is for the purpose of insulation to improve the energy efficiency namely in the buildings and dwellings. Nanotechnology has now provided an effective and affordable means to increase energy efficiency in pre-existing buildings as well as new construction by increasing thermal resistance. The major advantage of nano insulation materials is its benefit of translucent coatings which increase the thermal envelope of a building without reducing the square footage. The intrinsic property of nano insulating material is it can be applied to windows to reduce heat transfer from solar radiation due it its thermal resistant property and the translucent property allows diffusing of day light. The nano insulating material has significant advantage in reducing the operational energy aspects of buildings due to its valuable insulating properties. This paper examines applicable nanotechnology based products that can improve the sustainable development and overall competitiveness of the building industry. The areas of applying nano insulating material in building industry will be mainly focused on the building envelope. The paper also examines the potential advantages of using nanotechnology based insulating material in reducing the life cycle energy, reduction of material usage and enhancing the useable life span. The paper also investigates the operational energy by simulation methodology and compares the reduction of operational energy consumption.
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    Opening the door on refrigerator energy consumption: quantifying the key drivers in the home
    Harrington, L ; Aye, L ; Fuller, RJ (SPRINGER, 2018-08)
    There is little concrete understanding of the energy consumption of refrigerating appliances during normal use or the main influences on their energy consumption. To date, no widely accepted method to disaggregate measured energy consumption measured in the home into its key components has been demonstrated. This paper examines the main external factors that impact on the energy consumption of existing refrigerating appliances in the home and how they respond to changing conditions, namely: room air temperature, defrosting behaviour and user interactions. Analysis of field data from 235 homes in Australia demonstrates that room air temperature is by far the largest factor accounting for typically around 75% of total energy consumption. Where present, energy used for defrosting is relatively small at around 10%, but this does vary by household and the type of defrost controller. User interactions typically account for 15% of total energy consumed by main household refrigerating appliances, but this varies from a few percent to as much as 45% in large households. The method set out in this paper provides a basis for more in depth analysis and a better understanding of energy consumption of household refrigerators in different regions.
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    A Machine Learning Approach for the Performance Prediction of GCHPs with Horizontal Ground Heat Exchangers
    Zhou, Y ; Narsilio, G ; Makasis, N ; Aye, L ; LopezAcosta, NP ; MartinezHernandez, E ; EspinosaSantiago, AL ; MendozaPromotor, JA ; Lopez, AO (IOS PRESS, 2019-01-01)
    This study aims to provide a machine learning approach to predict the performance of Ground Coupled Heat Pumps (GCHPs) with horizontal Ground Heat Exchangers (GHEs). Specifically, an ANN model was developed for this purpose which can potentially be generally applied to similar sites at different locations and climate conditions, with even limited types of input data. In this example, a TRNSYS model regarding a typical horizontal trench within a rural farm in Australia, has been developed and verified, covering over 50 different yearly loading patterns under 3 different climate conditions. The simulated performance data is then used to train the artificial neural network. As results, the trained ANN is able to predict the performance of GSHPs systems with identical GHEs even under climatic conditions (and locations) that has not been specifically trained for. With only limited input data, the presented ANN shows no more than 5% error in most cases tested.
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    Current status and opportunities of hydrogen production from biomass
    AYE, L (ANZSES Australia & New Zealand Solar Energy Society, 2003)
    This paper investigates the current status of hydrogen production from biomass via thermal gasification and steam reforming and future opportunities. The current cost of central hydrogen production via this technology is found to be US$ 25/GJ HHV (US$ 3.6/kg H2) which is about two times more expensive than the current gasoline production cost for the same energy content. Further cost reduction opportunities exist with the integration of waste biomass (such as organic fraction of municipal solid waste, sewage, animal manures, forestry and agricultural residues) disposal.
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    Local walkability index: assessing built environment influence on walking
    Reisi, M ; Nadoushan, MA ; Aye, L (SCIENDO, 2019-12)
    Abstract Walking is a more sustainable transport mode, and governments around the world are trying to deliver highly walkable areas to their people. Due to its importance, walkability has been a research topic in recent years. Vast empirical studies have reported evidence related to the influence of built environment on walking as a major physical activity. Considering the recent literature, this study developed a framework to quantify walkability by applying a set of indicators related to built environment. The indicators were normalised, weighted and integrated into an overall walkability index. The research was conducted on Chaharbagh Street, which is a major and ancient street in the Isfahan metropolitan area, Iran. The proposed framework would be helpful in investigations of whether a specific area is an appropriate option for a car-free plan based on its built environment features. The outcome of the study could be applied to understand issues related to pedestrian infrastructure and to propose corrective actions.
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    Undisturbed ground temperature in Melbourne
    Shah, SK ; Aye, L ; Rismanchi, B ; Sadrul Islam, AKM ; Ruhul Amin, M ; Ali, M (AIP Publishing, 2019-07-18)
    The ground surface temperature changes with the diurnal cycle of solar radiation and ambient air temperature. However, the amplitude of the ground temperature variation diminishes with the increase of the depth of the ground and after a certain depth of the ground, it becomes almost constant, where is termed "undisturbed ground temperature (UGT)". At this depth, the seasonal changes of solar radiation and ambient air temperature changes will no longer affect onground temperature. It is one of the important parameters for designing of the ground heat exchangers and building energy analyses. In this study ground temperatures at various depths in Melbourne were investigated using a 40 m deep borehole instrumented with thermistors. The ground temperatures at various depths (0 m to 40 m) in Melbourne were also simulated by using three methods: Kasuda formula method, simulation (TRNSYS, Type 77), and simplified correlation (developed by Ouzzane et al. in 2015) and the results were compared with the measured data. Root mean square error (RMSE) and mean bias error (MBE)were used to validate and verify the methods. It was found that the estimated ground temperatures at 2, 21, and 40 m depths by Kasuda formula method and simulation (TRNSYS)have the same trends as that of the measured data. The measured annual temperatures of ground at 2 m depth were between 14.7°C and 19.8°C, while the temperature at 21 m and 40 m depths remained almost constant. RMSE and MBE of the simulation (TRNSYS, Type 77) were found to be 1.39°C, and -1.39°C respectively compared to measured data at 21 m depth. Based on these values, we conclude that simulation (TRNSYS, Type 77) can reliably predict the ground temperature for the selected site in Melbourne.
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    Effective use of offsite manufacturing for public infrastructure projects in Australia
    Gunawardena, D ; Mendis, P ; Ngo, D ; Rismanchi, B ; Aye, L (ICE Publishing, 2019)
    Prefabrication and offsite manufacturing have featured in various forms in an in-situ based construction industry for many decades. Scarcity of both human and material resources is challenging the future of traditional construction practices. Due to its many benefits such as speed of project delivery, minimum work on site, minimised construction waste and higher quality assurance, offsite manufacturing is gradually evolving into an essential technology in the construction industry. As a result of re-cent government initiatives, Australia is seeing a considerable increase in the use of offsite manufacturing and prefabricated modular technologies in delivering public infrastructure projects such as schools, healthcare facilities, and public transport facilities. Such projects are ably supported by academic research collaborating with the industry to ensure that the outcomes keep improving to achieve the highest quality and functionality. This paper discusses how multidisciplinary research addresses issues such as structural performance, construction technology, design for manufacturing and assembly and indoor environ-mental quality for the delivery of such public infrastructure projects. These projects have set an example in how offsite manufacturing supported by academic research can be beneficial for effectively delivering the greater good to the society.