Infrastructure Engineering - Research Publications

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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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    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.
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    A pilot study on users’ IEQ perceptions in a residential aged care facility in Melbourne
    Chau, H ; Aye, L ; Noguchi, M ; Newton, C ; Zhou, J ; Mei Min Woo, C ; Rajagopalan, P ; Andamon, M (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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    Thermal performance of concrete with PCMs
    JAYALATH, A ; Mendis, PA ; Aye, L ; Ngo, TD (University of Moratuwa, 2012-01-01)
    Development of energy efficient and environmentally friendly materials to reduce energy consumption in buildings is a major concern in today’s building and construction industry. Sustainable development of energy efficient materials in buildings needs to consider not only the mechanical properties such as strength and stiffness of structural materials but also thermal properties which includes heat capacity and thermal insulation. Concrete as most widely used construction material has a great potential to improve its heat storing capacity or thermal mass for their effective usage in buildings. One of the promising solutions is thermal energy storage with Phase change materials (PCM). 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. Moreover PCM absorbs the excess energy during cement hydration and reduces the possibility of formation of cracks within the concrete. This paper reviews available literature on Phase change materials in concrete, its application and discusses finite element modelling of thermal performance of composite concrete.
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    Innovative modelling and visualisation platform for sustainable cities - MUtopia
    Mendis, PA ; Ngo, TD ; Aye, L ; Malano, HM ; Rajabifard, A (University of Moratuwa, 2012)
    Now more than half the world’s population lives in towns and cities and this proportion will rise to nearly two thirds by 2030. Many cities worldwide are facing acute challenges, and therefore it is essential that all future developments are carried out on a sustainable footing. Through a web-based platform, MUtopia visualises and demonstrates in a quantifiable manner what impact a planned site development would have by representing best practice in all aspects of sustainable urban living on a relatively large scale. Sites may be new suburbs or rebuilt sections of the city large enough to require systematic planning. The project focuses on the development of an integrated modelling, analysis and visualization tool that helps the government and developers to make informed decisions to achieve such sustainable urban development and implementation. MUtopia integrates the streams of energy, waste, water and transport, based on land use, as well as social and environmental factors so that various planning scenar os or dependencies between factors can be tested. It is an integrated BIM and GIS tool. MUtopia would be an international first in an area of growing interest and need.
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    A holistic model for designing and optimising sustainable prefabricated modular buildings
    Gunawardena, DS ; Ngo, TD ; Mendis, PA ; Aye, L ; Crawford, RH ; Alfano, JA (University of Moratuwa, 2012)
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    Solar chilled drinking water sourced from thin air: Modelling and simulation of a solar powered atmospheric water generator
    Aye, L ; George, BA ; Wu, D ; Piantadosi, J ; Anderssen, RS ; Boland, J (Modelling and Simulation Society of Australia and New Zealand, 2013-12-01)
    It is expected that there will be water scarcity in the future under the changing climate. Therefore investigations of innovative and environmentally friendly ways to produce portable water are very much essential. Atmospheric water generators (AWGs) apply vapour compression refrigeration to extract water vapour from the surrounding air. They produce drinking quality water and they require moist air and electricity. The required electricity may be produced by solar photovoltaic (PV) panels. By using solar energy the environmental impacts of an AWG associated with electricity consumption could be substantially reduced. The availability of solar energy and high humidity of air coincide with the drinking water demand. As of today the performance characteristics of stand-alone solar PV powered AWG is unknown. To address this knowledge gap a simulation model of such system has been developed. The model focuses on an individual phenomenon such as solar radiation availability, solar PV electricity output, battery storage, moisture content in the air and heat and mass transfer at the vapour compression refrigeration. The aim of this paper is to present the transient model developed and the simulation results. Kasaragod district in the state of Kerala, India is selected as the study area. Drinking water availability is a major issue in this district during the months from February to early June. Daily climate variables like temperature, maximum and minimum relative humidity, wind speed and global solar radiation on horizontal plane and wind speed were obtained from a meteorological station located in Kasaragod. A simulation model has been developed in TRNSYS with the following components: PV modules, Batteries, Regulator, Inverter and Atmospheric Water Generator. By using the model developed the capacity of the AWG, the number PV modules, the capacity of the battery bank required were determined for minimum daily water production of 15 L. The water extraction efficiency of the AWG investigated varies between 5.4% and 9.3% for Kasaragod. The cooling CCOPs of the AWG investigated are between 4 and 5, which is better than conventional air-to-air heat pump. Based on the analysis it was concluded that the monthly average daily efficiency is strongly correlated to the monthly average relative humidity of the ambient air. The monthly average daily efficiency is defined as average of all the daily average efficiency for a month. The validation of the simulation model with experiments to enable practical system design optimisations, and the development of control algorithms to obtain better performance by using the validated model are recommended for the future studies.
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    INVESTIGATING POTENTIAL COMFORT BENEFITS OF BIOLOGICALLY-INSPIRED BUILDING SKINS
    Webb, M ; Aye, L ; Green, R ; Wurtz, E (INT BUILDING PERFORMANCE SIMULATION ASSOC-IBPSA, 2013)
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    An analysis of the feasibility and implications of using crude palm oil as renewable fuel for electricity generation in Indonesia
    Rahmadi, A ; Aye, L ; Moore, GA (Australian Solar Energy Society, 2014)
    This paper explores the use of Crude Palm Oil (CPO) as a renewable fuel for electricity generation in Indonesia to meet the government liquid biofuel target of 5% by 2025. Long-range Energy Alternatives Planning (LEAP) system was employed to model the Indonesian energy system and forecast the energy demand up to 2025. Annual energy demand was assumed to grow at 6% and PLN (Indonesia’s stateowned electricity company) business plan to meet a 94% electrification access in 2020 is used to forecast the electricity consumption. The results suggest that relying on CPO alone as the fossil fuel substitute in the electricity generation could not meet the biofuel target. However, combining the use of CPO in the power generation and implementing liquid biofuel blend in the demand consumption recommended by the engine manufacturers would increase the overall biofuel contribution to 5.8% of the total energy mix. This means meeting the national target by 2025 could be successful without compelling engine manufacturers to accommodate the higher biofuel to fossil fuel blending ratios. The target also requires a total liquid biofuel and CPO of about 27.1 GL in 2025. In energy terms, this is equivalent to 926 PJ or about 159 million barrels of crude oil. The results imply that it may have detrimental environmental impact, as it requires 5.5 Mha of land area for biofuel feedstock plantations. Preliminary estimate of greenhouse gas (GHG) emission due to land use alone could reach up to 62 Mt CO2-e annually. Such a release could be prevented and even promises a saving if the land sought for biofuel plantation comes from low carbon stock land cover. On the positive note, this could offer employment opportunities to about 3.57 million people as well as investment in the agricultural and biofuel processing industry.