Search Results (75)

Facing rapid urbanization, rising temperatures, and a residential sector that accounted for 38% of Egypt’s electricity use in 2022, middle-income housing presents a critical yet underexplored opportunity for energy efficiency improvements. This study investigates how the integration of passive design strategies and rooftop photovoltaic (PV) systems can enhance energy performance in this segment, using the Sakan Masr housing project in New Cairo as a case study. Addressing a research gap—namely the limited analysis of combined strategies in Egypt’s middle-income housing—the study follows a four-phase methodology: identifying dominant building orientations; simulating electricity demand and thermal comfort using DesignBuilder; optimizing the building envelope with passive measures; and evaluating PV system performance across south-facing and east–west configurations using PV-SOL. Results reveal that passive strategies such as improved glazing and shading can enhance thermal comfort by up to 10% and reduce cooling loads. Also, east–west PV arrays outperform south-facing ones, producing over 14% more electricity, reducing costs by up to 50%, and avoiding up to 168 tons of CO₂ emissions annually. The findings highlight that passive improvements with smart PV integration—offer a cost-effective pathway toward Net Zero Energy goals, with significant implications for national housing policy and Egypt’s renewable energy transition. Full article

With the rapid development of science and technology, the global demand for renewable energy is increasing. In the urban context, solar energy has become one of the key ways to increase urban energy self-sufficiency and reduce carbon emissions due to its flexibility in installation and ease of expansion of applications. Therefore, based on Geographic Information System (GIS) and deep learning modeling, this paper proposes a method to efficiently assess the potential of urban rooftop solar photovoltaic (PV), which is analyzed in a typical area of Lanzhou New District, which is divided into 8774 units with an area of 87.74 km². The results show that the method has a high accuracy for the identification of the roof area, with a maximum maxF_β of 0.889. The annual solar PV potential of industrial and residential buildings reached 293.602 GWh and 223.198 GWh, respectively, by using the PV panel simulation filling method for the calculation of the area of roofs where the PV panels can be installed. Furthermore, the rooftop PV potential of the industrial buildings in the research area provided can cover 75.17% of the industrial electricity consumption. This approach can provide scientific guidance and data support for regional solar PV planning, which should prioritize the development of solar potential of industrial buildings in the actual consideration of rooftop PV deployment planning. Full article

This study presents a comprehensive Life Cycle Assessment (LCA) of the NENGOUE residence, a multi-occupancy building located in Yaoundé, Cameroon, over an 80-year lifespan. The analysis encompasses four life cycle phases—construction, use, renovation, and deconstruction—and evaluates twelve environmental impact categories. The results reveal that the use phase contributes overwhelmingly to environmental burdens, accounting for over 96% of total impacts. To mitigate this dominance, two alternative scenarios were assessed: a sustainable transport model and the integration of a photovoltaic system. In the first scenario, environmentally friendly commuting strategies, such as increased walking, cycling, and public transport, led to a 17.10% reduction in greenhouse gas (GHG) emissions. In the second, rooftop photovoltaics offset 69.29% of the building’s electricity needs, resulting in a 26.72% GHG reduction. A third, combined scenario demonstrated the highest environmental gains, achieving a 42.97% reduction in GHG emissions, alongside substantial improvements across other impact categories, including acidification (−38.4%), cumulative energy demand (−28.3%), and photochemical ozone formation (−40.18%). In addition to the environmental benefits, the study highlights the importance of considering social acceptance, behavioral change, and economic feasibility for real-world implementation. The willingness of residents to adopt sustainable mobility practices, cultural preferences, safety concerns, and the initial cost barriers associated with photovoltaic technology are identified as critical factors. These findings underscore the need for integrated strategies that combine technological innovation with inclusive urban planning and stakeholder engagement. The proposed approach demonstrates that aligning environmental measures with local socio-economic realities can significantly enhance the sustainability of residential buildings, contributing meaningfully to climate change mitigation in Sub-Saharan African cities. Full article

This article attempts to estimate the potential of supplying a residential building in Europe with energy exclusively from RESs during a whole year, including the heating period. The aim of the tests carried out was to minimize the purchase of energy required to achieve the thermal comfort (HVACR + DHW) of a residential building powered solely by electricity. During the tests carried out, the EVs were used by the residents as their daily means of transport, topped up during working hours, and the excess energy remaining in their batteries was discharged into the building when they returned home. Energy for the EVs/PHEVs was sourced from RESs (mostly for free) while they were parked at the workplace, and also on the way home. Two one-month tests in the spring and autumn resulted in a state where, instead of purchasing a significant volume of black energy from the grid, the building was mostly powered by green energy from roof-top PVs and RES energy brought in by the PHEVs/EVs. This study identified days when the building became a real nZEB, which was not possible in previous years. The results of economic gains and carbon footprint reduction were calculated. After a period of testing, the degree of degradation of traction batteries used to carry the energy of EVs/PHEVs was checked. A high potential for such an operation was identified, especially in areas where there are periodic shutdowns (due to a call from the grid operator) of local RESs situated near the residential areas. The proposed solution may be of interest to all countries where the use of grid energy is associated not only with a doubling of costs (grid charges), but also with significant emissions, particularly in the heating period (e.g., Poland). Full article

Rising temperatures are intensifying residential cooling demands in hot–arid regions, with national building codes playing a pivotal role in mitigating these effects. This study evaluates the energy performance of two high-density residential buildings, Noor City in Cairo and Banan City in Riyadh, using DesignBuilder version 7.0.2.006 simulations for 2023, 2050, and 2080 under RCP 4.5 projections, followed by comparative and code-swapping analysis that assessed the role of envelope design parameters. All parameters were constant, except for those dictated by each country’s code. Results show that under future climate conditions, cooling loads in the uninsulated Noor City rise by 69% by 2080, compared to a 32% increase in Banan City. A code-swapping analysis confirmed the regulatory impact; applying the Saudi envelope to Noor City reduced annual energy use by over 40%, while using the Egyptian code in Banan City increased it by more than 50%. Solar exposure analysis further revealed that Noor City’s unshaded façades contribute to elevated thermal loads. Additionally, a 20.48 kWp rooftop photovoltaic system offsets 32:35% of annual energy consumption in both cases. While operational benefits are evident, no full life cycle cost (LCC) analysis was conducted; future studies should address economic feasibility to guide code adaptation in lower-income contexts. Full article

The Baltic countries are exploring diverse ways to achieve renewable energy objectives, with a particular emphasis on utilizing photovoltaic (PV) technologies in urban areas. Despite the northerly geographical location, PV energy has proven effective, particularly in individual households under the net metering scheme. Energy communities (EC) in urban areas have the potential to support sustainable energy transition by promoting local generation and increasing resilience. However, the broader adoption of rooftop PV systems faces numerous challenges, including technical limitations and legislative gaps. This study examines challenges encountered by community energy projects in residential apartments through a case study in the Latvian context. The paper provides a comparative analysis of PV community implementation scenarios across the three types of typical apartment buildings. The study demonstrates a number of fundamental obstacles that hamper the development of ECs in apartment buildings. The results indicate that the economic benefits of ECs largely depend on electricity market price, and that selection of optimal community design is the key aspect for minimizing investment risks amid market and legislative uncertainty. Results indicate that individual households may have limited motivation to form ECs under current policies. Finally, the insights provided help shape suggestions for future research. Full article

The integration of photovoltaic (PV) systems in buildings is crucial for reducing reliance on conventional energy sources while promoting sustainability. This study evaluates and compares three energy generation systems: rooftop PV, building-integrated photovoltaics (BIPV), and a hybrid combination of both. The analysis covers energy production, economic feasibility through the levelized cost of electricity (LCOE), and environmental impact by assessing unreleased carbon dioxide (UCD). A residential building in Kerman, Iran, serves as the case study. The results indicate that rooftop PV exhibits the lowest LCOE at USD 0.023/kWh, while BIPV has a higher LCOE of USD 0.077/kWh due to installation complexities. The hybrid system, combining both technologies, achieves a balance with an LCOE of USD 0.05/kWh while maximizing energy generation at 16.2 MWh annually. Additionally, the hybrid system reduces CO₂ emissions by 9.7 tons per year, surpassing the standalone rooftop PV (5.0 tons) and BIPV (4.7 tons). The findings highlight the synergistic benefits of integrating both PV systems, ensuring higher self-sufficiency and enhanced environmental impact. This research underscores the necessity of comprehensive urban energy planning to optimize renewable energy utilization and accelerate the transition toward zero-energy buildings. Full article

Rural areas are ideal for renewable energy facilities, supporting sustainable development and energy transition. Egypt aims to reduce greenhouse gas emissions in the electricity sector by 37% and energy consumption by 17% by 2030. Rural Egypt, hosting two-thirds of the population and building stock, consumes one-third of the total electricity. Thus, this paper provides an exploratory study to diagnose and benchmark the energy-use intensity of rural buildings and quantify the correlation between residential electricity consumption, built environment elements, and socio-economic factors, in addition to promoting techno-economic assessments of renewable energy from photovoltaic panels in rural Egypt, supporting national policies amid rapid rural development. The study utilized different analytical and field methods and statistical analyses. A typical agriculture-based rural village in the Delta region, northern Egypt, was selected; the built environment, building types, and socio-economic factors were examined. The results revealed a significant correlation between lifestyle, built-up area, household size, and floor numbers with residential buildings’ electricity consumption. The average annual electricity use intensity was benchmarked at 2.5–92.3 kWh/m² for six non-residential building typologies and at 22 kWh/m² and 6.67 kWh/dwelling for residential buildings. Under current regulations, rooftop solar panels can generate electricity significantly, but are not profitable. Eventually, insights for policymakers to inform energy transition policies and national initiatives for rural regeneration were provided. The research focused on a local context, but the methodology can be applied to rural settlements in similar contexts. Full article

Thermal comfort is a fundamental goal of architecture aiming at protecting individuals from harsh weather conditions. In Nigeria’s savanna climate zone, such as Kaduna, poor indoor thermal comfort leads to over-reliance on air-conditioning systems. There is limited research on the application of passive design strategies in the Nigerian savanna climate, which creates a barrier to their widespread implementation in residential buildings. In response to the increased awareness of climate change and the need for sustainable design, this study explores the potential of passive design strategies, focusing on the combination of rooftop insulation and reflective materials with mechanical ventilation as a means of improving indoor thermal comfort solutions. This study conducted a 3-day field experiment of typical dwellings in Kaduna, a major city in the Nigerian savanna climate zone. The data collected from this experiment served as the basis for a simulation study using EnergyPlus software, which tested and evaluated 3 different strategies: passive design (roof insulation + reflective materials), mechanical ventilation, and a combination of passive design and mechanical ventilation. This study highlights the potential for passive design strategies to provide a more sustainable, cost-effective solution, reducing dependence on air conditioning while supporting indoor comfort. Additionally, the research methodology and insights gained offer a basis for developing future building codes in Nigeria that emphasize sustainable practices. Such codes would guide architects, builders, and policymakers in designing homes that respond to local climate needs and align with broader sustainability goals. Further research could explore additional passive measures, including advanced window technologies, shading, and natural ventilation, to maximize sustainable residential design potential in tropical savanna climates. Full article

Domestic electricity consumption in the Kingdom of Bahrain accounts for 48% of total national electricity consumption, increasing between 1.5 and 3.5% annually. This increase is due to indoor cooling electricity accounting for up to 80% of domestic electricity consumption. The Kingdom is aiming for a reduction in carbon emissions of 30% by 2035 and to achieve carbon neutrality by 2060. Hence, reducing electricity consumption is necessary. Recently, the Kingdom’s Electricity and Water Authority has issued updated building regulations regarding the maximum thermal transmittance allowed for residential buildings. This study employed a quantitative simulation of a typical housing unit (T8) in the Kingdom of Bahrain, assessing building envelope materials and air conditioning efficacy following the updated building regulations via DesignBuilder V. 7.0.2.006 software. Additionally, this study examined the potential of building regulations to facilitate the transition to net-zero energy buildings by comparing electricity consumption with renewable energy generated from rooftop photovoltaic panels. It was determined that electricity consumption could be reduced by up to 52% by following building regulations and relying on current materials in the residential sector. Furthermore, this reduction may facilitate the Kingdom’s attainment of net-zero energy status through onsite power generation of 12,500 kWh/year. This study concluded that achieving net-zero energy status is possible by following building regulations and relying on commercially accessible construction materials; however, guidelines for energy storage or a feed-in tariff for the residential sector must be established. Full article

In this paper, an optimization-based analysis approach is presented to cost-effectively improve the energy efficiency of residential buildings in Morocco. This study introduces a unique focus on the Moroccan context, where a comprehensive application of energy efficiency optimization has not yet been undertaken. This analysis considers the interactive effects among various energy efficiency measures to determine optimal combinations for designing high-energy performance, as well as net-zero energy, residential buildings for six climate zones in Morocco. In particular, the design analysis approach combines a whole-building simulation with the sequential search technique, providing a novel, integrated cost–benefit analysis that minimizes lifecycle costs (LCC) while maximizing energy savings for each climate zone. This study also includes an unprecedented comparison of optimized designs, reference designs, and current Moroccan building regulations (RTCM), highlighting potential improvements to the existing regulatory framework. While the sequential search method has been applied elsewhere, its specific application to achieve net-zero energy homes in the Moroccan context with comparable LCC is a new contribution. The analysis results show that houses in Morocco can be cost-effectively designed to achieve annual energy savings of 51% for Zone 1, 53% for Zone 2, 60% for Zone 3, 67% for Zone 4, 54% for Zone 5, and 56% for Zone 6 compared to the current construction practices considered as reference designs. Moreover, the results indicate that houses can reach net-zero energy building designs with almost the same LCC as the reference design cases for all the climate zones in Morocco. Full article

As the world increasingly embraces renewable energy as a sustainable power source, accurately assessing of solar energy potential becomes paramount. Photovoltaic (PV) systems, especially those integrated into urban rooftops, offer a promising solution to address the challenges posed by aging energy grids and rising fossil fuel prices. However, optimizing the placement of PV panels on rooftops remains a complex task due to factors like building shape, location, and the surrounding environment. This study introduces the Roof-Solar-Max methodology, which aims to maximize the placement of PV panels on urban rooftops while avoiding shading and panel overlap. Leveraging geographic information systems technology and 3D models, this methodology provides precise estimates of PV generation potential. Key contributions of this research include a roof categorization model, identification of PV-ready rooftops, optimal spatial distribution of PV panels, and innovative evaluation technology. Practical implementation in a real urban setting demonstrates the methodology’s utility for decision making in the planning and development of solar energy systems in urban areas. The main findings highlight substantial potential for PV energy generation in the studied urban area, with capacities reaching up to 444.44 kW. Furthermore, implementing PV systems on residential rooftops has proven to be an effective strategy for reducing CO₂ emissions and addressing climate change, contributing to a cleaner and more sustainable energy mix in urban environments. Full article

Urban expansion and fossil fuel dependence have led to energy and environmental concerns, highlighting the need for sustainable solutions. Rooftop photovoltaic (RPV) systems offer a viable solution for urban energy transition by utilizing idle rooftop space and meeting decentralized energy needs. However, due to limited information on building function attributes, detailed assessments of RPV potential at the city scale are still complicated. This study introduces a cost-effective framework that combines big Earth data and deep learning to evaluate RPV potential for various investment entities. We introduced a sample construction strategy that considers built environment and location awareness to improve the effectiveness and generalizability of the framework. Applied to Shanghai, our building function recognition model achieved 88.67%, 88.51%, and 67.18% for accuracy, weighted-F1, and kappa, respectively. We identified a potential installed capacity of 42 GW with annual electricity generation of 17 TWh for industrial and commercial, 16 TWh for residential, and 10 TWh for public RPVs. The levelized cost of electricity ranges from 0.32 to 0.41 CNY/kWh, demonstrating that both user-side and plant-side grid parity was achieved. This study supports sustainable development by providing detailed urban energy assessments and guiding local energy planning. The methods and findings may offer insights for similar studies globally. Full article

The present study investigates the incorporation of renewable rooftop photovoltaic systems in fully electrified residential buildings and estimates the zero-energy demand building potential in relation to the climatic data of Greece. Specifically, the aim of the analysis is to calculate the maximum possible number of stories and therefore the total building height for a complete transformation to zero-net-energy building. The energy analysis, which is conducted using the DesignBuilder software, focuses on single-floor up to seven-story buildings. The importance of the present work lies in the acknowledgment of the diversity of the Greek residential sector, the adherence to national energy policies, and the European goal of fully electrified buildings. The examined case studies are equipped with electrically driven air-to-air heat pumps serving the space heating and cooling demands and with an air-to-water heat pump covering the domestic hot water requirements. The investigated locations are the four main cities of Greece, Athens, Thessaloniki, Chania, and Kastoria, which represent the country’s four climatic categories. The conducted analysis allows for the mapping of the zero-energy building potential for the climatic data of Greece, demonstrating the possibility of striking a positive building energy balance through the integration of on-site renewable energy sources and the production of necessary electrical energy. The novelty of the present work lies in the identification of a key factor, namely, the building height, which determines the feasibility of transforming multifamily buildings into zero-energy buildings. According to the analysis results, the critical number of stories is calculated at six for Chania, five for Athens, four for Thessaloniki, and two for Kastoria. Regarding a three-story residential building, the incorporation of a renewable photovoltaic system can result in an annual surplus electricity production of 13,741 kWh (Chania), 10,424 kWh (Athens), and 6931 kWh (Thessaloniki), and a corresponding coverage of 100% (Chania), 69.0% (Athens), 38.9% (Thessaloniki) and 0% (Kastoria). Full article

Australia, like many other countries around the world, is undergoing a transition toward net zero emissions. It requires changes and development in many sectors, which not only bring benefits but also challenges. The rapid growth in renewable energy sources (RESs) is necessary to decarbonise electricity generation but negatively affects grid stability. Residential buildings also contribute to this issue through specific load profiles and the high penetration of rooftop photovoltaic (PV) installations. Maintaining grid balance will be crucial for further emissions reductions. One of the potential solutions can be the replacement of conventional heating and cooling systems in houses with solutions capable of storing energy and shifting the electrical load. As presented in this paper, heat pumps and hydronic systems can significantly improve the electrical load of a typical South Australian household when they are controlled by algorithms reacting to the current grid conditions and household-generated electricity compared to conventional solutions. TRNSYS 18 simulations of air source and ground source heat pump systems with smart control based on measured electricity consumption and domestic hot water usage data showed the possibility of total energy consumption reduction, shifting the load from peak periods towards periods of excessive RES generation and increasing self-consumption of rooftop PV electricity. These improvements reduce the amount of emissions generated by such a household and allow for further development of other sectors. Full article