Growing global demand for sustainable and reliable energy systems has intensified interest in renewable multigeneration technologies for buildings, particularly in coastal regions where multiple energy resources are simultaneously available. In this study, a hybrid solar-wind-ocean thermal energy system is proposed and comprehensively assessed as an integrated solution for supplying electricity, heating, and cooling to buildings, while also producing hydrogen and oxygen as valuable by-products. Building energy demand was estimated using a detailed simulation platform, and system performance was evaluated through thermodynamic analysis coupled with a two-stage optimization framework. In the first stage, an artificial neural network integrated with a genetic algorithm was employed for global optimization. In the second stage, response surface methodology was used to refine the optimal region identified in the first stage and to examine the interaction effects of the most influential operating parameters. The optimized system achieved an exergy efficiency of 59.83% and a total cost rate of 99.04 $/h, showing improved performance relative to the initial global optimization stage. The results demonstrate that the proposed hybrid configuration can provide a balanced and resilient renewable energy supply while significantly reducing reliance on conventional energy sources. Among the investigated coastal climates, Melbourne showed the most favorable overall performance due to its stronger renewable energy potential. The findings further indicate that the system is capable of meeting annual building demands for electricity, heating, and cooling while also generating surplus hydrogen and oxygen, underscoring its potential to support sustainable and zero-energy building strategies. In addition, by displacing conventional electricity generation, the proposed system can avoid approximately 2078 tons of CO2 emissions annually in Melbourne, highlighting its environmental advantages and its potential contribution to cleaner coastal energy systems.

The rapid growth of the building sector, alongside its significant contribution to the climate crisis, has heightened the need for technologies that improve sustainability. Prefabricated buildings (PBs) offer a major solution, whose benefits can be evaluated through Life Cycle Sustainability Assessments (LCSA) to support informed decisionmaking. However, conventional LCSA approaches often overlook circularity (disassembly and reuse potential) and temporal dynamics (time-dependent changes), leading to incomplete evaluations. This study addresses this gap by integrating circularity and temporal dynamics into the life cycle sustainability of PBs, through two main contributions: (1) evaluating sustainability via a system dynamics-based LCSA framework under circularity and dynamism-informed design scenarios, and (2) performing a comparative static-dynamic analysis to quantify the impact of temporal variations on sustainability. Applied to a disassemblable prefabricated building in Western Australia, ambitious end-of-life strategies that prioritise reuse and recycling increased circularity by nearly 20%, though higher circularity did not always guarantee environmental gains (e.g., an 11.8% increase in circularity accompanied a 9.5% reduction in carbon footprint, while a 15.2% increase led to a 14.46% rise in embodied energy), highlighting the need for multi-objective optimisation. Comparative static versus dynamic assessments showed that static approaches overestimate impacts, with discrepancies up to 14% for a 20-year service life, whereas dynamic simulations captured long-term benefits, including up to 80% reductions in operational emissions under decarbonisation scenarios. The framework is proposed to be integrated into design-stage decision-making, enabling stakeholders (designers, engineers, construction managers, policymakers, and clients) to minimise long-term financial risks.

Seasonal contrasts between hemispheres pose major challenges to solar energy availability and demand management, yet no previous solar-thermal multi-generation study has systematically evaluated system robustness across mirrored latitudes with opposite seasonal patterns. This study presents a solar thermal multi-generation framework designed to ensure reliable, year-round performance across contrasting hemispheric climates. The proposed system integrates a heliostat field, central receiver, molten-salt thermal storage, a Solar Rankine cycle for power generation, a recuperator for domestic hot water and space heating, and an absorption chiller for cooling. Four representative cities, Sydney and Melbourne (Australia), and Ahvaz and Isfahan (Iran), were selected for their roughly similar latitudes, contrasting climates, and reliable meteorological data, enabling a consistent hemispheric comparison of system adaptability. The methodology combined Building Energy Optimization (BEopt) simulations, thermodynamic modeling in Engineering Equation Solver (EES), and multi-objective optimization using Response Surface Methodology (RSM). Under optimal operation, the system achieved an exergy efficiency of 19.42% producing 1,629.6 MWh of electricity, 10,527.8 MWh of heating, and 1,446.8 MWh of cooling annually in Isfahan. Carbon Dioxide (CO2) emissions decreased by 332.43 tons per year relative to baseline, and the cost rate was optimized to $169.93/h. The results confirm that the framework maintains stable performance under seasonal reversals, an aspect rarely quantified in solar thermal multi-generation research. The study introduces two key novelties: a hemispheric robustness evaluation framework and a transferable methodology that links building-level demand modeling with thermodynamic simulation and optimization, offering a scalable pathway toward climate-responsive, zero-energy residential systems.

Long-term planning of water distribution system (WDS) rehabilitation is challenged by multiple sources of long-term uncertainty, under which the deterioration in system performance continues to evolve over time. Traditional rehabilitation approach typically assumes pre-defined intervention timing, which limits the flexibility in the rehabilitation strategy. This may lead to inefficient decisions when future system conditions deviate from expectations, thus reducing the hydraulic reliability of the system. To address this, a proactive planning framework has been developed, which consists of two components: 1) identifying optimal rehabilitation timing through system performance evaluation and 2) determining optimal rehabilitation actions through optimisation. A real-world case study has been used to evaluate the effectiveness of the proactive planning approach in comparison with the traditional approach. Results show that, by allowing rehabilitation actions to be timed in response to evolving system performance, construction-related disruptions can be minimised while the system reliability is effectively maintained. In addition, compared to the traditional approach, the proactive planning approach leads to more flexible and cost-effective rehabilitation plans, achieving substantial savings, especially in capital infrastructure investment. This study highlights the importance of timely rehabilitation in enabling WDSs to adapt to uncertain future conditions, ensuring long-term reliability and sustainability under uncertainty.

The rapid growth in renewable energy generation has heightened the need for enhanced energy storage capacity. Micro Pumped Storage (MPS) offers a dual-function alternative to conventional batteries by integrating energy storage with non-potable water supply (NPWS) in high-rise buildings. This study hypothesises that jointly optimising MPS operation for emissions and water reuse can improve both environmental and economic performance. A multi-objective genetic algorithm (GA) is developed to optimise monthly scheduling under timevarying electricity prices and emission factors, incorporating penalty-based constraints to ensure water supply reliability. Our findings indicate that optimising MPS schedule can reduce operational emissions, with reductions of 4 % to 25 % in ES mode, and 25 % to 43 % in NPWS mode. Additionally, the NPWS mode reduces potable water consumption by up to 3000 m3 annually, which translates to saving 54 MWh of energy and 44 tonnes of CO2 within Melbourne's water distribution network. These environmental and economic benefits contribute to a reduction in the payback period of MPS installations by up to 20 years, particularly in NPWS mode. Compared to equivalent-capacity lithium-ion batteries, MPS systems offer shorter payback periods and additional sustainability benefits. Furthermore, MPS provides a viable pathway to secure sustainability certification such as Green Star, and support urban decarbonisation through integrated water-energy optimisation. Practical challenges, however, must be addressed for wider adoption.

Under-utilised rooftops in Multi-owned Buildings (MOBs) represent a vital yet untapped potential for renewable energy generation in urban areas. However, equitable energy allocation and shared benefits pose substantial challenges, hindering Renewable Energy Systems (RES) adoption. This study introduces a policy-driven adaptive framework integrating building and region-specific parameters to identify suitable energy allocation models, facilitating widespread RES adoption. The framework assesses the physical and managerial MOB characteristics, such as building age, height, and common property ownership type, alongside regional parameters, including renter proportion, affordability, and regulatory conditions. Consequently, five policy instruments are analysed, identifying how tailored region-specific policy interventions can mitigate risks, enabling equitable energy allocation. A case study in Melbourne demonstrates that high-density, low-affordability regions like the Central Business District benefit from floor area allocation models when supported by financial incentives, while affluent regions like South Melbourne thrive with dedicated legal platforms supporting energy allocation. Our findings underscore the importance of adaptive, region-specific policies over the one-size-fits-all approach for advancing RES adoption. This adaptive model selection framework, enhanced with digital twin technology for scenario analysis, offers policymakers a data-driven tool for making informed decisions, supporting resource efficiency and sustainability, and laying a pathway for equitable RES integration across urban settings.

Decarbonising heating and cooling often focuses on electrification, with heat pumps and decentralised generation playing key roles. This transition poses economic and environmental challenges, particularly in the production, operation, and disposal of these systems. However, greenhouse gas emissions from heating and cooling equipment are often overlooked. This study evaluates whether fifth-generation district heating and cooling (5GDHC) systems offer a better alternative to traditional heat pumps and chillers for electrifying heating and cooling in buildings. We introduce a framework to compare the performance of 5GDHC systems with traditional alternatives, focusing on engineering, economic, and environmental aspects. The framework uses linear programming, cradle-to-grave life cycle assessment, and a global sensitivity analysis to support decision-making under uncertainty. It is applied to five case studies: Brisbane, Melbourne, New York City, Paris, and Singapore, under three scenarios: current trends, and slow and rapid electrification aiming for net zero by 2050 and 2040. Results show that 5GDHC systems can reduce annualised costs, which include capital and operational costs, by up to 26% and GHG emissions by up to 21%, with self-sufficiency rates up to 98%. This framework aids planners and policymakers in making informed decisions for sustainable urban energy solutions, emphasising the importance of an early, holistic assessment.

Fifth-generation district heating and cooling (5GDHC) systems have the potential to provide simultaneous heating and cooling, allowing for energy exchange between users with different needs. However, their viability in mild climates with a higher share of cooling demand remains unclear. In this paper, we propose a framework for assessing the engineering, economic and environmental performance of a 5GDHC system compared to a state-of-the-art business-as-usual solution and demonstrate it through a practical case study for a university campus in Melbourne, Australia. When accessible heat sources and sinks are available, the 5GDHC system provides a cost-effective solution, with annual cost savings between 9 and 29 % and GHG emissions reduction between 25 and 58 % compared to an already advanced business-as-usual system. Additionally, by using peak off-peak tariffs and an hourly emission factor for the electricity consumed, we demonstrate the 5GDHC operational flexibility in pursuing different objectives, such as minimising cost or emissions, respectively. The results suggest that 5GDHC systems are an economically and environmentally viable solution in milder climates, and a successful implementation of 5GDHC in Australia can create new market opportunities and pave the way for its adoption in other countries with similar climatic conditions and no established history of district heating systems.

Adopting Renewable Energy Systems (RES) in Multi-Owned Buildings (MOBs) is critical for achieving sustainability goals, yet the equitable allocation of energy from a jointly-owned RES to individual apartments remains overlooked in practice and literature. Current practices, rooted in models of common cost allocation, fail to address the dynamic traits of energy allocation and disregard the energy entitlement of each apartment, necessitating a tailored approach for renewable energy allocation in MOBs. This paper emphasises energy entitlement and introduces a novel, evidence-based decision-making framework assessing nine distinct energy allocation models for their suitability in diverse MOB typologies, characterised by physical and social factors, and presents a ranked list. Our findings reveal extensive variation in model suitability depending on the building typology. Equal energy allocation minimised financial disparities, while demand-based allocation was significantly effective for older, mid-rise buildings with fewer tenants. Conversely, the flat-fee model was found unsuitable regardless of building type. Furthermore, the study demonstrates that the suitable model for a building typology may not always align with the objectives of RES installation, thus endorsing an ‘objective proximity’ analysis. The proposed framework serves as a valuable guide for stakeholders, including the owners’ corporations, policymakers, and industries, to make well-informed decisions for a smooth transition to renewable energy. It lays the foundation for potential expansion to other building types while underscoring the necessity for adaptive policies in promoting RES adoption.

With the growing global demand for cooling, there is a critical need for sustainable solutions that efficiently provide both heating and cooling. Fifth-generation district heating and cooling (5GDHC) systems present a promising option, integrating renewable energy and enabling energy sharing. Despite their potential, the environmental performance of 5GDHC systems has not been comprehensively studied until now. This study addresses this critical gap by conducting the first comprehensive cradle-to-grave life cycle assessment of 5GDHC systems, uniquely incorporating hybrid environmental flow coefficients. This approach significantly enhances the coverage and accuracy of the analysis compared to traditional assessment methods. Using the University of Melbourne’s proposed Fishermans Bend campus as a case study, we compare different 5GDHC configurations with a state-of-the-art traditional system. Our findings reveal that 5GDHC systems can reduce total life cycle GHG emissions by up to 52%, particularly when suitable heat sources and sinks are available. This study underscores the importance of considering life cycle impacts in the early planning stages of energy systems, positioning 5GDHC as a viable solution for the energy transition.

Most energy exchanges take place through the building skin. The skin characteristics play a decisive role in the extent of these exchanges, but they are somewhat more varied in the double skin façade (DSF). Among these characteristics, cavity segmentation has a noticeable effect on the implementation of the DSF in different directions during the hot and cold seasons. The aim of this study was to investigate the role of DSF segmentation in energy consumption and natural ventilation of high-rise buildings in hot and dry climates. This study used DesignBuilder software to study sixty-four segmentation component scenarios in an eight-story residential building in Isfahan, Iran. Moreover, a proposed hybrid model utilizing the hybridization of the Hunger Game Search and Gradient Boosting (HGS-GB) algorithm was employed to estimate energy consumption in various scenarios involving lighting, heating, cooling, and total scenarios. The available outcomes revealed that the HGS-GB model had a better performance in comparison with other individual models, such as Gradient Boosting (GB), Random Forest (RF), and K-nearest neighbors (KNN). The R2 values for lighting, heating, cooling, and total energy estimation were 0.9993, 0.9958, 0.9991, and 0.9922, respectively. The findings of this study suggest the significance of DSF segmentation in energy consumption and natural ventilation in high-rise buildings in hot and dry climates.

The increasing energy demand for space cooling, projected to triple by mid-century and surpassing a quarter of today's global electricity usage, underscores the urgent need for innovative, more energy-efficient air-conditioning technologies. The research introduces phase change material (PCM) embedded radiant cooling (PCMRCC) as a promising solution, offering enhanced energy efficiency and indoor environmental quality. Despite its potential, PCM-RCC remains in the developmental stage, requiring further research to fully unlock its benefits. This work aims to analyse the operational performance of PCM-RCC and develop an advanced rule-based control strategy to enhance its efficiency further. The analysis was conducted using a validated PCM-RCC transient system simulation model. To quantify the advantages of PCM-RCC over typical radiant cooling and evaluate the effectiveness of the proposed control strategy, two reference cases are defined: (1) basic-controlled PCM-RCC, and (2) radiant cooling without PCM. Results reveal that PCM-RCC with advanced control demonstrates higher load flexibility (-93% off-peak time operation), 12% less electricity usage, a 5% coefficient of performance improvement, and a 30% decrease in operational costs compared to radiant cooling. Furthermore, the proposed system shows 9% lower energy usage with a 20% improvement in thermal comfort compared to basic-controlled PCM-RCC.

Many smart technologies have been introduced in buildings with the aim to reduce the energy and GHG emissions associated with their operation, particularly through improved control systems for regulating heating, ventilation and air conditioning (HVAC) equipment. Despite their energy saving potential, only a few studies have comprehensively assessed the costs associated with their practical implementation from a life cycle perspective. Accordingly, this study quantifies and compares the life cycle costs of a smart HVAC control system with that of a traditional control system, in the context of an Australian office building. For both systems, the required hardware are specified based on the characteristics of these systems and the layout of the serviced spaces in the reference building. The costs incurred over the period of assessment are quantified using the net present cost (NPC) approach. To evaluate the effects of these control systems on the operational energy costs of the building HVAC system, the control logics of both these systems are modelled through building energy simulations. The results show that, over the period of assessment, the smart control system incurred a higher total cost compared to the traditional control system. However, the findings from the simulations show that the HVAC energy cost savings achieved through the specification of the smart control system offset the additional cost incurred to deploy this system over the traditional control system. The smart control system resulted in HVAC operational cost savings between 9 % and 10 % compared to the traditional control system. Sensitivity analyses indicated that the total life cycle costs varied between -27 % and +50 %, with the discount rate and energy price increase rate being the most influential parameters.

Growth in renewable energy generation leads to an urgent need of expanding energy storage capacity. While large pumped hydro storage remains the most established and prevalent energy storage method, there is potential for evaluating its applicability on a micro scale in urban areas. This study develops a multi-objective optimisation model in Python to assess the feasibility of micro pumped-storage (MPS) for high-rise buildings up to 300 m in height, considering different future energy market conditions. The findings indicate that increasing electricity tariff values lead to improved solutions from both environmental and financial perspectives across all building heights. However, for buildings 50 m or less, the MPS is currently considered economically unviable. In a world first, this study examines the techno-economic viability of MPS systems as a function of building height and different water storage types, including modular tanks, multilayer green roofs, blue roofs, and nearby streams. The MPS system using modular tanks and nearby streams boasts the shortest payback period (4.8 years) and Net Present Value of A$ 600 k over the MPS lifetime. The study provides insights into feasible flow rates and storage sizes. The findings are valuable for designers, helping them decide if MPS is feasible based on the building's height and features.

Urban Green Space management requires a multi-dimensional, evidence-based approach to effectively balance social, environmental, and economic objectives. City administrators currently lack a data-driven framework for allocating resources during constraint scenarios, leading to subjective decisions. Existing literature lacks objective solutions for managing city-scale green spaces, each with its distinct characteristics. Another challenge is handling varied spatial scales required for urban applications. This study proposes a novel goal programming-based model for urban green space management wherein multiple benefit objectives, such as conserving sequestered carbon in trees and enhancing quality and accessibility of parks, as well as handling demand constraints on available resources like water and personnel, are included. The proposed method was demonstrated in two cities with diverse conditions, Berlin and Melbourne, and evaluated on various benefit metrics, such as allocated green space units, resources consumed, and goals achieved. The model was analyzed with resource allocation decisions and goals at different spatial scales. The highest benefit achievement and resource allocation were observed when resources were allocated at the sub-district scale with a city-level target. Alternatively, setting targets at the district level provided a more even resource distribution; however, at the cost of reduced overall benefits. Results show that the proposed method increased the total benefits gained while effectively balancing conflicting goals and constraints. Additionally, it allows incorporating the city’s preferences and priorities, offering a scalable solution for informed decision-making in varied urban applications. Depending on data availability, this approach can be scaled to other cities, including additional benefits and resource constraints as required.

Expanding the sustainable energy storage capacity is important due to the growth of renewable energy supplies. As pumped storage and utility-scale batteries are two important methods of energy storage, this study investigates the sustainability of micro pumped storage (MPS) units compared to lithium-ion (Li-ion) batteries for electricity storage. The analysis focuses on the levelised cost of storage (LCOS) and levelised embodied emissions (LEE) for small-scale energy storage solutions within the Australian context. This research aims to identify MPS configurations that are economically and environmentally competitive with Li-ion batteries, determine the minimum rooftop area for MPS efficiency, and assess MPS energy storage capacity at an urban scale. The analysis includes three upper water storage options: Modular Tank (T), Green Roof (GR), and Blue Roof (BR); and two lower storage configurations: Modular Tank and Nearby Stream (S). These configurations are coded by the notation: upper storage type/lower storage type, and are evaluated across buildings of varying heights. The results show that MPS has a significant economic advantage over Li-ion batteries as storage capacity increases, particularly in configurations applied T for upper water storage. MPS outperforms Li-ion in buildings over 150, 50, 100, and 50 m height for T/T, T/S, GR/T, and GR/S configurations respectively. Environmentally, MPS configurations generally have lower LEE than Li-ion batteries, with GR setups demonstrating the most significant benefits, while BR configurations have higher emissions. The study also identifies the minimum rooftop area required for MPS installations to be viable, showing that incorporating nearby streams can enhance the feasibility of MPS in buildings with smaller rooftops. However, the findings reveal that MPS systems are generally less advantageous than battery systems for buildings with rooftop areas smaller than 1,175 m2. Finally, despite only up to 28 buildings in Melbourne meeting the optimal MPS criteria, the ability to store up to 14 MWh/day confirms MPS as a viable, sustainable alternative to Li-ion batteries under specific conditions, contributing to global sustainable energy efforts.

This work presents an in-depth systematic literature review of the strategies used to characterise and quantify thermal comfort conditioned by mechanical HVAC systems. The model development is paramount for the study on the stability and robustness of the ventilation process control. They are required to establish supervisory and local control loops to improve the component sequence of the HVAC systems, and the interaction among the indoor environment, occupants, and the HVAC system response. Over the past decade, innovative technologies and artificial intelligence revamped the HVAC control research with a reluctancy of application in practice due to complex computations and lack of understanding for these innovations. However, the need to find the balance between the functionality of the HVAC system and suitable comfort levels of occupants still persisted. This work examines three research clusters of HVAC systems: zone thermal conditions representation, the inherent nonlinearity of HVAC complex systems and model reduction strategies, and HVAC processes optimisation and control methods. This enables a holistic view of the complexities folded in delivering occupants’ thermal comfort. Central to constructing these research clusters, existing studies were investigated following the four-step protocol based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines: identification of relevant literature based on keywords, screening of the chosen literature quality, setting eligibility criteria for scoping the objectives of the study and lastly inclusion of literature categories into one set. Based on the findings of this work, the application of linearisation and model reduction is found to be a promising area of research in the field of HVAC system control and optimisation. This is because emerging deep learning methods could facilitate the integration of linearisation to high-dimensional data of zone thermal interactions presented by computational fluid dynamics. Finally, this work discusses the challenges faced in the data-driven control strategies of HVAC systems, opens future direction of evaluating occupants’ comfort and highlights the importance of interpretability and tracking of control process in relation to thermal comfort.

Climate change is posing a growing threat to cultural heritage buildings, and many cities lack the capacity to manage these risks. One significant challenge is flooding, which can cause significant damage to heritage buildings. A literature review identified gaps in current research on heritage adaptation, including: a lack of tools for assessing the vulnerability of asset-specific cultural heritage buildings to flooding and providing recommendations for adaptation; limited examples of successful architectural adaptation of cultural heritage buildings to flooding impacts; and insufficient consideration of values, such as aesthetic, in adaptation tools. In response to these gaps, we developed a Heritage Building Flood Robustness Toolkit that incorporates both architectural and engineering considerations. The Toolkit is designed as a decision support tool to assist asset owners and key stakeholders, such as community groups, to make more quantified and informed decisions on heritage adaptation. The Toolkit includes three key advancements: an enhanced component-based methodology for individual cultural heritage building flood vulnerability assessments; improved recommendation of adaptation strategies aided by component-based risk assessments; and integration of user values, including aesthetic implications, into adaptation recommendations through adopting a Structured Decision-Making process. The Toolkit was tested on two buildings in Cockatoo Island, Sydney (Australia) with different materials and construction techniques. The results highlight the Toolkit's ability to support decision-making through more precisely assessed adaptation strategies based on asset-specific flood damage assessments and its sensitivity to user preferences, particularly aesthetic impacts from adaptation implementation. The Toolkit can be used as an instrument by planners, designers, and councils to enhance the protection of cultural heritage against flooding in the future.(c) 2023 The Author(s). Published by Elsevier Masson SAS on behalf of Consiglio Nazionale delle Ricerche (CNR). This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )