Infrastructure Engineering - Research Publications

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    Assessing the opportunity for producing hemp-based insulation in the Australian market
    Christopher, P ; Aye, L ; Nematollahi, N ; Ngo, T (EJSE International, 2024-04-29)
    By-products (wastes or residues) of renewable materials have the potential to be manufactured into higher value fibre insulation products for the Australian market. Currently, such products have been imported for servicing the Australian market. This presents a potential opportunity to divert considerable quantities of waste from landfill and produce a high performance, locally made, low carbon, natural fibre insulation product for the Australian domestic and commercial building industry. This article assesses the hemp-based bulk insulations available in the Australian market.
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    Mechanical properties and life cycle greenhouse gas analysis of textile waste fibre-based concrete
    Jayalath, A ; Sofi, M ; Ginigaddara, T ; Gou, H ; Mendis, P ; Aye, L (Elsevier BV, 2024-05-17)
    The application of textile waste as an aggregate in concrete enhances sustainability in construction and promotes circular economy. This work develops a novel fibre-based concrete incorporating textile waste fibres. The experiments showed that including textile waste fibres reduces flowability of concrete and improves its tensile and compressive strengths, alongside strain resistance. The fibres enhance concrete’s ductility and resilience against environmental damage. Textile waste fibre exhibits a lower greenhouse gas emissions compared to other non-polymer fibres. This work emphasises the benefits of textile waste in enhancing construction sustainability and highlights the need for expanded exploration.
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    Sizing behind-the-meter solar PV for pumped water distribution systems: A comparison of methods
    Zhao, Q ; Wu, W ; Yao, J ; Simpson, AR ; Willis, A ; Aye, L (Elsevier BV, 2024-01-01)
    Water distribution systems (WDSs) are vital urban infrastructure systems. To meet increasing pumping energy demands and minimise environmental impacts, behind-the-meter (BTM) solar photovoltaic (PV) systems have been considered by water utilities. However, there currently is not a systematic approach to size BTM solar PV for WDSs, considering the life cycle performance of the integrated systems. This study evaluates three methods to size BTM solar PV in pumped WDSs: 1) the heuristic method developed from current industry practice; 2) the minimum total life cycle cost (TLCC) method based on the system minimum TLCC; and 3) the minimum payback method to minimise the time needed to pay off the solar capital investment. The performance of the integrated water-solar system has been assessed against economic, energy and emissions performance metrics using two case studies. The results indicate that the heuristic method leads to the largest solar PV size, potentially oversizing the system. The minimum payback method leads to the smallest solar PV system, potentially under-sizing the system. The minimum TLCC method leads to more balanced system performance, but the solar PV size determined using this method is sensitive to the discount rate used. The insights into the performance of the system sized using the three methods provide decision-makers guidance to select appropriate solar PV systems for WDSs.
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    High water use plants influence green roof substrate temperatures and their insulative benefits
    Pianella, A ; Zhang, Z ; Farrell, C ; Aye, L ; Chen, Z ; Williams, NSG (Elsevier BV, 2023-12-01)
    Green roofs are amongst the solutions employed to deliver sustainable buildings in cities. Their vegetation and substrate layers can reduce the heat transfer through the roof, thus potentially reducing energy used for building cooling and heating. However, little research has investigated the insulative properties of drought-tolerant plants which also have high water use. These plants have been found to improve runoff retention by removing larger volumes of water from the substrate through higher transpiration rates than succulents. This planting strategy may also enhance green roof cooling performance due to their greater evapotranspiration rates. In this study, the thermal performance of three drought-tolerant species with high water use — Lomandra longifolia, Dianella admixta, and Stypandra glauca — was evaluated and compared with a commonly used succulent species (Sedum pachyphyllum) and a bare unplanted module. L. longifolia had the best insulative performance during the entire investigated period, reducing green roof substrate surface temperature up to 1.86 °C compared to succulent S. pachyphyllum. In summer, the mixture reduced heat gain to a greater extent than monoculture plantings of all species except L. longifolia. Summer measurements also suggest that plants with high leaf area index (LAI) and higher albedo should be selected to reduce surface temperatures. High evapotranspiration rates of high water use L. longifolia led to greatest reduction of bottom surface temperatures during a heatwave when decreasing its water content from 18.5% to 2.9%. Results obtained using an analytical hierarchical partitioning technique indicated air temperature had the most significant impact on temperatures at both the surface of the planting substrate and the bottom of each green roof unit, accounting for 48% to 58% of the variation.
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    Comparison of waste photovoltaic panel processing alternatives in Australia
    Suyanto, ER ; Sofi, M ; Lumantarna, E ; Aye, L (Elsevier BV, 2023-09-15)
    This work aims to compare end-of-life (EoL) alternative processing scenarios of waste photovoltaic panel in Australia. Landfill, generic waste electrical and electronic equipment recycling (European business-as-usual (EU BAU)), full-recovery EoL photovoltaic (FRELP), and Modified FRELP are the alternative processing scenarios considered for the next five years. Environmental analysis by a simplified life cycle assessment is performed using Material, Energy, Chemical, and Other (MECO) matrix. This semi-quantitative comparison eliminates reliance on LCA software and environmental expertise for preliminary screening. Financial analysis is also performed by using a life cycle costing (LCC) approach. Overall, comparative findings are consistent with full-quantitative LCA and LCC despite magnitude differences. Simplified analysis merely reflects process complexity and resource consumption. A full financial insight can only be acquired when non-resource-derived costs are incorporated. Considering the increasing trend of waste levies and landfill ban extending into the future, landfill is no longer the cheapest option in Australia. Consequently, mass-based waste recovery for landfill diversion facilitates cost savings. Recovering 8% more waste with FRELP compared to modified FRELP has the potential to save $19 more per tonne of processed PV waste. EU BAU is the most eco-efficient interim solution, while waste volume is still low. Modified FRELP saves 321 kg CO2-e emission by avoiding traditional incineration. The focus on reclaiming solar-grade silicon rather than silver has the potential to attract $154 more revenue per tonne compared to FRELP.
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    Efficient HVAC system identification using Koopman operator and machine learning for thermal comfort optimisation
    Wahba, N ; Rismanchi, B ; Pu, Y ; Aye, L (Elsevier BV, 2023-08-15)
    The aim of this article is to improve the efficiency of heating, ventilation, and air conditioning (HVAC) systems by using a linear control approach. Conventional HVAC systems use a wall thermostat and a simplified ON/OFF controller to condition the thermal environment, but this approach is not always efficient in meeting indoor heat loads. To address this issue, we propose using the Koopman operator combined with Machine Learning, a linear embedding method, to model the nonlinear behaviour of thermal comfort indices. Specifically, we use the Predictive Mean Vote (PMV) index, which has been a superior indicator of occupants’ thermal sensation. We apply Computational Fluid Dynamics to create high-dimensional training, testing, and validation datasets, and a deep autoencoder network framework to map the original nonlinear coordinates of the PMV index into a latent space where the system is behaving linearly. Our results show that the Koopman autoencoder can reproduce and predict data from the latent space, enabling offline system identification for the zone thermal conditions and this has the potential to improve HVAC feedback control systems.
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    Fire safety performance of 3D GFRP nanocomposite as a cladding material
    Soufeiani, L ; Nguyen, KTQ ; White, N ; Foliente, G ; Wang, H ; Aye, L (ELSEVIER SCI LTD, 2022-10)
    Vertical fire spread along highly flammable claddings is a major safety issue for buildings. In this project, a potential new type of cladding material, 3D Glass Fibre Reinforced Polymer (3D GFRP) with improved thermal stability, and fire performance is developed. 3D GFRP nanocomposite samples were fabricated with different percentages of Sepiolite (Sep), Sepiolite-phosphate (SepP), Ammonium Polyphosphate (APP) flame retardant, and 3D glass fabrics. Synthesis of SepP, dispersion analysis of nanoparticles, and manufacturing process have been studied. The characterisation of materials was conducted using Scanning Electron Microscopy, Helium Ion Microscopy, Transmission Electron Microscopy, Thermogravimetric Analysis (TGA), and X-ray Diffraction Analysis. The thermal stability and fire behaviour of the 3D GFRP nanocomposite was studied via TGA and cone calorimeter test. TGA results showed that the optimum amount of additives that improved the thermal stability is 15% flame retardants. Results of cone calorimeter tests showed that different percentages of APP, Sep, and SepP decreased the peak of the heat release rate between 4% and 42%. Also, the effects of APP flame retardant in improving thermal and fire reaction properties were more than Sep and SepP. The test results of 3D GFRP nanocomposite also showed a prospective cladding that can benefit the construction industry in near future.
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    The life aquatic
    McNiven, B ; Aye, L ; Holzer, D (AIRAH, 2023-05-01)
    Students and academics from the University of Melbourne joined forces with industry consultants and local government representatives to explore achieving net zero carbon design for those most energy-intensive buildings: aquatic centres. The university’s Brendon McNiven, Dominik Holzer and Lu Aye, F.AIRAH, elaborate.
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    Thermal and energy performance evaluation of a full-scale test cabin equipped with PCM embedded radiant chilled ceiling
    Mousavi, S ; Rismanchi, B ; Brey, S ; Aye, L (Elsevier BV, 2023-06-01)
    The escalating global demand for space cooling has led to the emergence of new cooling technologies, including the phase change material embedded radiant chilled ceiling (PCM-RCC) system. This technology improves energy efficiency and indoor environmental quality, while also offering demand-side flexibility. The present study experimentally evaluates the thermal efficiency and energy performance of a PCM-RCC system in a full-scale test cabin equipped with PCM panels. Here, the transient thermal behaviour of PCM ceiling panels besides the cooling energy delivered during charging-discharging cycles are examined. The indoor thermal comfort and peak electricity demand reduction enabled by the present PCM-RCC are also discussed. The results reveal that chilled water circulation for 4–5 h overnight was sufficient to fully recharge the PCM panels. Over 80% of the occupancy time was classified as “Class B″ thermal comfort according to ISO 7730. The system's daily electricity usage was mostly concentrated during off-peak hours, accounting for ∼70% of the total usage. While the controlling schedule used in this study responded to the transient thermal behaviour of the indoor space and PCM ceiling panels, a more dynamic, predictive schedule is necessary to improve the system's overall efficiency and further enhance indoor thermal comfort in response to the changing environmental conditions.
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    Emergency
    McNiven, B ; Aye, L ; Holzer, D (Australian Institute of Refrigeration, Air Conditioning and Heating (AIRAH), 2022-10-31)
    As part of the i-Hub project, masters-level architectural and engineering students from the University of Melbourne, industry consultants, university academics, and Ambulance Victoria staff embraced the challenge of designing net zero emergency response stations. The university’s Brendon McNiven; Lu Aye, F.AIRAH; and Dominik Holzer discuss.