Infrastructure Engineering - Research Publications
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ItemNo Preview AvailableA multi-layered energy resilience framework and metrics for energy master planning of communities: A university campus case study(Society of Risk Analysis, 2021-12-05)
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ItemDaily and seasonal thermal energy storage for enhanced flexible operation of low-temperature heating and cooling network(Ecos 2021 , 2021)Synergic operation of electricity, heating and cooling networks can bring savings and low carbon footprint through energy efficiency. In such context, the present work proposes a novel Smart Thermal Loop (STL) solution: a fully electrified thermal generation and distribution system where a low-temperature underground loop and reversible heat pumps are used to supply users’ heating and cooling demand. Additionally, STL includes short and long-term thermal energy storage (TES) by means of sensible storage tanks and geothermal boreholes. The proposed solution is described and investigated in the case of the new campus of the University of Melbourne (with aggregated peak load of about 2 and 3 MWth, respectively, for heating and cooling). A numerical model is proposed to simulate the yearly operation of STL with 1-hour resolution. Key features include (i) network model for the underground loop to track temperature evolution over space and time, (ii) variable heat pump performance, which depends on network temperatures, (iii) physical model for the heat transfer between system and soil, in the geothermal storage, (iv) modelling of the interaction between neighbouring boreholes. Results explore the dynamics of the integrated STL system, with a focus on the role that energy storage over different timescales plays in enabling efficient and flexible operation of system components. TES contribution to system operation goes beyond the use of low-price electricity and allows energy savings through efficient scheduling of heat pumps operation and reduction of pumping work. Benefits from the flexible operation of STL are quantified as a 10% reduction in energy expenditure and 28% in system running costs. The presented model can also instruct on the impact of different design choices on STL operation.
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ItemNumerical simulation of single-sided natural ventilation: Impacts of balconies opening and depth scale on indoor environment (IOP Conference Series: Earth and Environmental Science (EES), 2019)Heating Ventilation and Air Conditioning (HVAC), including, Mechanical ventilation (MV) in the building sector accounts for around 40% of electricity consumption and a large percentage of Greenhouse Gas (GHG) emissions. Natural ventilation (NV), as an alternative method, assist in decreasing energy consumption as well as harmful emissions. Balconies, a common architectural element in high rise residential buildings, could enhance NV and reduce reliance on mechanical ventilation in cooling dominant climates. Indoor air velocity (IAV) and distribution due to NV is less predictable than MV, and the impacts of balcony geometry on IAV and distribution profile have not yet been classified. This study, focusing on single-sided ventilation apartments, seeks to determine to what extent balcony depth and door opening area impacts on the indoor environment of the attached living area. For this, 3D – steady-state Computational Fluid Dynamics (CFD) simulations were conducted using ANSYS Fluent. The simulation results were validated against measured data in a full-scale experimental study in a residential building in subtropical Brisbane, Australia. Five different openings and nine depth scenarios were modelled, with results showing variances in indoor mean air velocity and temperature. The outcomes suggest that further research on the indoor distribution of temperature and air velocity may provide further clarity on the impact of balcony geometry on occupant comfort through NV.
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ItemNumerical simulation of single-sided natural ventilation: Impacts of balconies opening and depth scale on indoor environment (SEGT 2019, 2019)Heating Ventilation and Air Conditioning (HVAC), including, Mechanical ventilation (MV) in the building sector accounts for around 40% of electricity consumption and a large percentage of Greenhouse Gas (GHG) emissions. Natural ventilation (NV), as an alternative method, assist in decreasing energy consumption as well as harmful emissions. Balconies, a common architectural element in high rise residential buildings, could enhance NV and reduce reliance on mechanical ventilation in cooling dominant climates. Indoor air velocity (IAV) and distribution due to NV is less predictable than MV, and the impacts of balcony geometry on IAV and distribution profile have not yet been classified. This study, focusing on single-sided ventilation apartments, seeks to determine to what extent balcony depth and door opening area impacts on the indoor environment of the attached living area. For this, 3D – steady-state Computational Fluid Dynamics (CFD) simulations were conducted using ANSYS Fluent. The simulation results were validated against measured data in a full-scale experimental study in a residential building in subtropical Brisbane, Australia. Five different openings and nine depth scenarios were modelled, with results showing variances in indoor mean air velocity and temperature. The outcomes suggest that further research on the indoor distribution of temperature and air velocity may provide further clarity on the impact of balcony geometry on occupant comfort through NV.
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ItemUndisturbed ground temperature in Melbourne(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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ItemEffective use of offsite manufacturing for public infrastructure projects in Australia(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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ItemSharing Urban Renewable Energy Generation Systems as Private Energy Commons(Springer International Publishing, 2020)This study tested a new methodology for simulating shared electricity generation among small groups of neighbours with Ostrom (1994) principles of common pool resource (CPR) (human behaviour-based) efficiencies. The approach does not not anticipate exclusive off-grid communities but instead, diverse energy users taking advantage of the averaging effects of aggregation, the social benefits of a CPR and direct action on emissions. The study tested three groups of 5 adjacent- or same-building- neighbours for three months to measure how electricity demand (import) is affected by an in-home display issuing nudges and sanctions by the group around a simulated (limited capacity) shared solar and battery system. A control group of 6 homes’ energy data was obtained for the same period. All three groups reduced their energy demand with weak but significant correlation between stimulus and reduced energy demand and one group significantly shifted demand toward available shared solar energy resources during the intervention.
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ItemNo Preview AvailableSeasonal solar energy storage system for space heating in cold climate(Australian PV institute, 2017-12-05)A seasonal solar energy storage system for space heating in cold climates is proposed. The system includes evacuated tube solar collectors integrated with double U-tube vertical borehole thermal storage coupled with a heat pump. The performance of the system is evaluated by computer simulations for a cluster of typical houses in four Asia-pacific cities: Ulaanbaatar (Mongolia), Harbin (China), Dras (India) and Lukla (Nepal). TRNSYS, a transient systems simulation program, was used to simulate the system. The typical detached house model for each city was developed based on the type of dwelling. The initial sizes of the system components were determined for the four cities. The average ground temperatures and energy balance of the system during charging and discharging modes were investigated. The seasonal heating coefficient of performance of the system in each city has been presented. The simple payback period (SPBP) of the proposed system was investigated by comparing convention system. It was found that the proposed system has the potential for fulfilling the space heating demand in cold climate cities of Asia-Pacific region.