Infrastructure Engineering - Research Publications
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ItemApplication of Artificial Neural Networks for Virtual Energy Assessment(MDPI, 2021-12-01)A Virtual energy assessment (VEA) refers to the assessment of the energy flow in a building without physical data collection. It has been occasionally conducted before the COVID-19 pandemic to residential and commercial buildings. However, there is no established framework method for conducting this type of energy assessment. The COVID-19 pandemic has catalysed the implementation of remote energy assessments and remote facility management. In this paper, a novel framework for VEA is developed and tested on case study buildings at the University of Melbourne. The proposed method is a hybrid of top-down and bottom-up approaches: gathering the general information of the building and the historical data, in addition to investigating and modelling the electrical consumption with artificial neural network (ANN) with a projection of the future consumption. Through sensitivity analysis, the outdoor temperature was found to be the most sensitive (influential) parameter to electrical consumption. The lockdown of the buildings provided invaluable opportunities to assess electrical baseload with zero occupancies and usage of the building. Furthermore, comparison of the baseload with the consumption projection through ANN modelling accurately quantifies the energy consumption attributed to occupation and operational use, referred to as ‘operational energy’ in this paper. Differentiation and quantification of the baseload and operational energy may aid in energy conservation measures that specifically target to minimise these two distinct energy consumptions.
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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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ItemLessons Learned from PCM Embedded Radiant Chilled Ceiling Experiments in Melbourne(Instituto Superior de Engenharia do Porto, 2021-09-14)Buildings are responsible for over a third of energy consumption worldwide, particularly for the increasing demand of air-conditioners in response to the more extreme heat around the globe. It is imperative to move towards more energy-efficient space cooling alternatives. The integration of phase change material (PCM) with a radiant chilled ceiling (RCC) is a promising technology due to its benefits regarding energy efficiency and indoor environmental quality. This article presents a field study conducted on a newly-developed PCM embedded radiant chilled ceiling (PCM-RCC) installed in a stand-alone cabin located in Melbourne. The study evaluates the thermal and energy performance of the system through investigation of the transient thermal behaviour of PCM panels in charging-discharging cycles, the indoor comfort conditions, and the electricity peak demand. It was observed that the proposed PCM-RCC can provide satisfactory comfort conditions and contribute to load shifting if a refined operating strategy is applied. The efficiency of PCM recharge overnight depends on several factors that need to be carefully considered in design. The challenges related to the implementation of optimal operating dynamic schedules in response to the thermal behaviour of PCM-RCC, and accurate weather forecasting should be addressed to realise the full potential of this technology.
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ItemLessons Learned from PCM Embedded Radiant Chilled Ceiling Experiments in Melbourne(Elsevier, 2022-06)Buildings are responsible for over a third of energy consumption worldwide, particularly for the increasing demand of air-conditioners in response to the more extreme heat around the globe. It is imperative to move towards more energy-efficient space cooling alternatives. The integration of phase change material (PCM) with a radiant chilled ceiling (RCC) is a promising technology due to its benefits regarding energy efficiency and indoor environmental quality. This article presents a field study conducted on a newly-developed PCM embedded radiant chilled ceiling (PCM-RCC) installed in a stand-alone cabin located in Melbourne. The study evaluates the thermal and energy performance of the system through investigation of the transient thermal behaviour of PCM panels in charging-discharging cycles, the indoor comfort conditions, and the electricity peak demand. It was observed that the proposed PCM-RCC can provide satisfactory comfort conditions and contribute to load shifting if a refined operating strategy is applied. The efficiency of PCM recharge overnight depends on several factors that need to be carefully considered in design. The challenges related to the implementation of optimal operating dynamic schedules in response to the thermal behaviour of PCM-RCC, and accurate weather forecasting should be addressed to realise the full potential of this technology.
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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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ItemNo Preview AvailableDataset on validation of double U-tube borehole and seasonal solar thermal energy storage system TRNSYS models( 2021-08-09)This dataset includes data from the validation of double U-tube borehole and seasonal solar thermal energy storage system TRNSYS models. The simulated transient temperatures at various points of the systems were compared with the measured ones. To quantify the agreement between each simulated and measured temperature of interest, mean bias error (MBE), root mean square error (RMSE) and correlation coefficient (CC) were applied.
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ItemNo Preview AvailablePandemic products and volatile chemical emissions(Springer, 2021-01)The recent pandemic (COVID-19) has seen a sweeping and surging use of products intended to clean and disinfect, such as air sprays, hand sanitizers, and surface cleaners, many of which contain fragrance. However, exposure to fragranced cleaning products has been associated with adverse effects on human health. Products can emit a range of volatile chemicals, including some classified as hazardous, but relatively few ingredients are disclosed to the public. Thus, relatively little is known about the specific emissions from these products. This study investigates the volatile organic compounds (VOCs) emitted from “pandemic products” that are being used frequently and extensively in society. In addition, among these emissions, this study identifies potentially hazardous compounds, compares so-called green and regular versions of products, and examines whether ingredients are disclosed to the public. Using gas chromatography/mass spectrometry, 26 commonly used pandemic products, including 13 regular and 13 so-called green versions, were analyzed for their volatile emissions. Product types included hand sanitizers, air disinfectants, multipurpose cleaners, and handwashing soap. All products were fragranced. The analyses found the products collectively emitted 399 VOCs with 127 VOCs classified as potentially hazardous. All products emitted potentially hazardous compounds. Comparing regular products and green products, no significant difference was found in the emissions of the most prevalent compounds. Further, among the 399 compounds emitted, only 4% of all VOCs and 11% of potentially hazardous VOCs were disclosed on any product label or safety data sheet. This study reveals that pandemic products can generate volatile emissions that could pose risks to health, that could be unrecognized, and that could be reduced, such as by using fragrance-free versions of products.
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ItemAlternative Heating and Cooling Systems for the Retrofit of Medium-Rise Residential Buildings in Greece(WILEY-V C H VERLAG GMBH, 2021-09-12)The European Union recently set the target of doubling building retrofit rates through the European Green Deal. Currently, more than half of the households’ energy consumption is accounted for space conditioning, with southern European countries experiencing increasing demand for cooling systems over the past decade. This article compares the performance of market-available heating and cooling systems that can replace the existing low-efficiency systems in multi-residential buildings in Greece. The study objectives are to minimize the operating greenhouse gas emissions and the life-cycle cost. Results demonstrate that air-to-air heat pumps have the lowest life-cycle cost. In areas where natural gas is not available, the replacement of the diesel-oil boiler with a biomass boiler leads to a 48% to 73% decrease of the operating greenhouse gas emissions. In areas where natural gas is available, the gas absorption heat pump has the lowest operating greenhouse gas emissions, demonstrating a reduction between 40% and 54% when compared to a conventional gas boiler; however, it dramatically increases the life-cycle cost, making it less attractive than heat pumps and condensing gas boilers. The findings are in line with the current residential space conditioning market, while indicating the potential of biomass boilers and gas absorption heat pumps.
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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.