Infrastructure Engineering - Research Publications

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    Fire resistance of a prefabricated bushfire bunker using aerated concrete panels
    Nguyen, T ; Ngo, DT ; Tran, P ; Mendis, P ; Aye, L ; Kristombu Baduge, KS (Elsevier, 2018-06-20)
    Prefabricated lightweight aerated concrete (PLAC) panels provide low thermal conductivity, potentially high stiffness-to-weight ratios, cost-effective material and structural systems and rapid modular construction. These panels can be utilised as floor slabs or external walls for various applications in building construction. The fire performance of the PLAC panel is examined in this work for a particular case, namely a prefabricated emergency bushfire shelter, which is one of the key applications of PLAC panels. Since, bushfires have unique heating curves, standardised tests are not useful and the system needs to be tested in a manner such that the heat flux of an actual bush fire can be reproduced. In this study, the fire performance enhancement of dual-skin bushfire bunkers, which are comprised of lightweight concrete and base metal thickness (BMT) steel, are examined experimentally and validated numerically. The Speedpanel PLAC modular panel explored in this work is a lightweight wall system primarily used for acoustic and thermal insulation purposes. Burning experimental studies of a single panel and dual-skin bunkers are carried out on a full scale. The experimental results are compared with fire safety codes for building materials to identify the key areas for improvements. A fire dynamic numerical model has been developed in this work using the Fire Dynamics Simulator (FDS) to simulate the burning process of PLAC structures. Numerical results of heat production are presented in comparison with experimental observations for validating the computational model. The proposed numerical model is used to predict the fire performance of a dual-skin bushfire bunker, demonstrating the need to have at least two PLAC layers to ensure fire safety compliance.
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    Time-efficient post-disaster housing reconstruction with prefabricated modular structures
    Gunawardena, T ; Tuan, N ; Mendis, P ; Aye, L ; Crawford, RH (Open House International Association, 2014-09-01)
    With many natural disasters such as earthquakes, cyclones, bushfires and tsunamis destroying human habitats around the world, post-disaster housing reconstruction has become a critical topic. The current practice of post-disaster recon- struction consists of various approaches that carry affected homeowners from temporary shelters to permanent hous- ing. While temporary shelters may be provided within a matter of days as immediate disaster relief, permanent hous- ing can take years to complete. However, time is critical, as affected communities will need to restore their livelihoods as soon as possible. Prefabricated modular construction has the potential to drastically improve the time taken to pro- vide permanent housing. Due to this time-efficiency, which is an inherent characteristic of modular construction, it can be a desirable strategy for post-disaster housing reconstruction. This paper discusses how prefabricated modular struc- tures can provide a more time-efficient solution by analysing several present-day examples taken from published post- disaster housing reconstruction processes that have been carried out in different parts of the world. It also evaluates how other features of modular construction, such as ease of decommissioning and reusability, can add value to post- disaster reconstruction processes and organisations that contribute to the planning, design and construction stages of the reconstruction process. The suitability of modular construction will also be discussed in the context of the guidelines and best practice guides for post-disaster housing reconstruction published by international organisations. Through this analysis and discussion, it is concluded that prefabricated modular structures are a highly desirable time-efficient solu- tion to post-disaster housing reconstruction.
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    Optimisation and financial analysis of an organic Rankine cycle cooling system driven by facade integrated solar collectors
    Wu, D ; Aye, L ; Tuan, N ; Mendis, P (ELSEVIER SCI LTD, 2017-01-01)
    The use of a solar cooling system has the potential to reduce the amount of energy required for cooling buildings. One of the most important methods of improving energy efficiency in buildings is by carefully designing building façades. A façade integrated evacuated tube collector (ETC)-organic Rankine cycle (ORC)-vapour compression cycle (VCC) was applied in this study. To optimise the design parameters of ORC, a steady-state semi-empirical model was developed in Engineering Equation Solver (EES). The optimum number of plates in each heat exchanger is obtained by maximising the net present value (NPV) of electricity savings. The financial performance of the optimised system was assessed through a unit cooling cost (UCC) analysis. It was found that the UCC of the optimised facade integrated ETC-ORC-VCC system is $0.24 per kWhr of cooling effect.
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    Effects of phase change material roof layers on thermal performanceof a residential building in Melbourne and Sydney
    Jayalath, A ; AYE, L ; Mendis, P ; Ngo, T (Elsevier, 2016-04-05)
    This paper assesses the effectiveness of Phase Change Materials (PCMs) for the improvement of the thermal performance and the thermal comfort of a residential building in Melbourne. The incorporation of PCMs in buildings with their significant heat storage capacity can delay the heat transfer and reduce the cooling and heating loads. Numerical simulation is a useful tool for comprehensive assessments and optimization of PCM applications in buildings. Thus an available TRNSYS component, PCM Wall: Type1270, was implemented with Type56 (Multi zone component). PCM Wall TRNSYS component has been validated with some experimental data published in the open literature. The validated model was then utilised to simulate the thermal performance of a residential building which has a PCM roof layer. The building is a typical single-storey, three bed room residential building in Melbourne. It was found that the PCM roof layer can reduce the cooling and heating loads whilst providing better thermal comfort for occupants with reduced indoor temperature fluctuations.