Search Results (344)

Lhasa combines abundant solar resources with a high heating demand and low winter solar altitude, making residential morphology simultaneously important to operational energy use and roof–façade photovoltaic (PV) generation. Based on a residential-area inventory covering more than 80 residential areas and 15 typical slab-type blocks, this study developed locally constrained parametric prototypes and generated 2186 valid physics-based samples. Thirteen morphological predictors were retained for surrogate modelling, followed by sunlight-constrained bi-objective optimization at floor area ratio (FAR) = 1.5, 1.8, and 2.2. On the independent test set, the selected energy and PV surrogate models achieved R² values of 0.999 and 0.989, respectively. The Pareto fronts at FAR = 1.5 and 1.8 included near-zero annual net-energy solutions, whereas FAR = 2.2 retained a minimum deficit of 0.682 × 10⁶ kWh. Low-energy solutions generally favoured a lower site coverage, continuous elongated slabs, and a greater mean height, whereas high-generation solutions favoured larger building footprints, a lower height, and controlled shading. As FAR increased, façade PV made a larger contribution, but this was insufficient to offset the decline in the rooftop supply and the rise in total energy demand. Energy-balance-oriented solutions generally concentrated the building orientation within 5–15° and the building depth within 14.0–15.5 m, with the density and height requiring a joint adjustment across FAR scenarios. The results provide an interpretable basis for the early-stage morphology screening and planning control of slab-type residential development in Lhasa. Full article

This research presents an integrated techno-energetic framework to decouple electric vehicle (EV) fleet growth from urban grid instability, using Bogotá, Colombia, as a case study. As emerging megacities confront rising charging demands, conventional reactive grid reinforcements are becoming technically and economically constrained. To address this, we develop a multi-layered optimization model that transforms urban Voronoi polygons into operational energy catchment units. Utilizing a Monte Carlo Tree Search (MCTS) algorithm, the framework determines infrastructure deployment sequences under two operational thresholds: a target high-resilience EV-to-charger ratio and a conservative scenario. Each localized node is technically dimensioned as a Representative Charging Station (RCS) equipped with a photovoltaic array and a Battery Energy Storage System (BESS). The results reveal spatial heterogeneity; high-density polygons in specific commercial and residential districts exhibit elevated infrastructure utilization alongside a stable solar resource baseline. Furthermore, the model demonstrates that this distributed architecture alleviates transformer thermal stress during the peak nocturnal charging period, mitigating localized overload risks and supporting distribution grid operational reliability. This study provides a scalable decision-making tool that bridges geospatial urban planning with renewable energy engineering to support the transition of constrained electrical networks. Full article

The rapid expansion of residential photovoltaics (PV) increases the need for long-term evidence on system performance under real operating conditions. This study compared four grid-connected rooftop PV microinstallations (4.69–5.04 kWp) located in the Sandomierz Basin, southeastern Poland, over 2022–2025. Monthly alternating-current production from SolarEdge monitoring was combined with regional sunshine duration and mean air temperature from the IMGW Sandomierz station, providing 192 installation–month observations. Specific yield, capacity factor, a model-based estimate of the performance ratio (PR_AP), Pearson correlations, ordinary least-squares regression, and sensitivity analysis of a documented failure were applied. Mean annual specific yields were 1077.7, 1061.7, 908.6, and 779.6 kWh/kWp for PV-I–PV-IV, respectively, while mean PR_AP estimates were 82.2%, 82.5%, 70.6%, and 65.5%. Sunshine duration was strongly correlated with monthly specific yield (r = 0.830–0.983; p < 0.001), and the combined model explained 88.8% of its variability. Excluding the zero-output failure month of PV-IV increased R² for the sunshine–yield relationship from 0.689 to 0.812 and improved the combined-model fit from 0.888 to 0.921. Greater nominal capacity did not guarantee higher normalized productivity. Regional solar-resource information should therefore be complemented by monitored operational data to support design, benchmarking, fault detection, and local distributed-energy planning. The findings also support SDG 7 by providing evidence for more reliable, locally adapted planning and operation of household photovoltaic systems. Full article

The integration of photovoltaic generation, battery storage, electric vehicles, smart appliances, and dynamic electricity pricing has made residential energy management a challenging real-time optimization problem. Conventional demand-side management methods often depend on fixed rules and are less effective under uncertain solar generation, changing tariffs, and variable user demand. To address this issue, this paper proposes a Proximal Policy Optimization-based deep reinforcement learning framework for smart home energy management. The proposed PPO controller learns adaptive scheduling decisions using real-time PV output, electricity price, battery state of charge, EV charging status, and appliance operating conditions. The controller coordinates shiftable, controllable, and non-shiftable loads while reducing electricity cost and maintaining user comfort. The proposed method is compared with DDPG and TRPO. Simulation results show that PPO reduces the average daily energy cost by 4.7% compared with TRPO and 8.3% compared with DDPG. The results confirm that PPO is an effective and stable approach for real-time residential demand-side management. Full article

Building-applied photovoltaics (BAPV) offer a practical retrofit pathway for the prefabricated social housing estates of Central and Eastern Europe. This study assesses the solar and photovoltaic potential of post-WW II housing districts in Poznań, Poland, through a multi-scale workflow spanning the city, district, and building levels. Measured municipal rooftop data for 336 residential buildings in four districts were combined with tree-inclusive parametric solar simulations, calibrated against the rooftop solar cadastre (normalized mean bias error of +0.4% after calibration), to select South Winogrady and two representative buildings. Three PV design scenarios were then evaluated in roof, facade, and combined configurations using a techno-economic model that incorporates manufacturer-warranted degradation, maintenance, inverter replacement, and a ±25% electricity price and installation cost sensitivity envelope. Roof configurations pay back in 6.6–7.2 years (30-year return on investment of 286–321%), facade systems are economically defensible only on the best-exposed surfaces (8.9–13.8 years), and all configurations remain profitable even under the pessimistic bounding case. ENVI-met simulations of the same scenarios show localized pedestrian-level reductions in the Universal Thermal Climate Index of up to 2.41 °C near the PV-equipped buildings, persisting under 2050 climate projections. The results provide a transferable evidence chain for prioritizing BAPV retrofits in standardized post-war housing stock. Full article

Cold-climate dwellings can face coincident electricity and domestic hot-water shortfalls in winter, when solar availability is at its lowest. This study evaluates an integrated residential system for Aomori, Japan, combining photovoltaics, evacuated-tube solar water heating, and battery storage with electrolysis, compressed-hydrogen storage, and a PEM fuel cell operated in combined-heat-and-power mode. Building on a screening-level annual-balance analysis, a coupled annual TRNSYS simulation with a 0.125 h time step resolved battery dispatch, electrolyzer part-load operation, hydrogen compression and finite storage, seasonal fuel-cell operation, and heat recovery. The results show that the principal value of seasonal hydrogen lies in improving winter supply adequacy, dispatchability, and heat recovery rather than annual conversion efficiency. Fuel-cell heat recovery increased the number of days satisfying the hot-water screening indicator—a daily mean tank temperature of at least 43 °C—from 221 to 332. A reserve-aware criterion identified a 225 W electrolyzer operating-power cap as the positive-reserve case; 205 W was near-cyclic with a negligible margin, whereas the original 475 W cap was substantially oversized. The hydrogen pathway remained markedly less efficient than direct photovoltaic and solar-thermal use, and the estimated storage hardware’s lower bound substantially exceeded the break-even capital ceiling supported by the annual operating value. Seasonal hydrogen can therefore strengthen winter energy adequacy and heat recovery but is not yet cost-effective at the single-dwelling scale under the investigated conditions. Full article

Rural houses in cold regions of China usually have high energy demands, particularly for space heating and domestic hot water. Passive design can reduce building energy demand, but additional renewable energy systems are still needed to improve on-site energy supply. This study evaluates the performance and limitations of photovoltaic (PV) and solar water heating (SWH) systems in a passive-designed rural house in Xi’an, China. Hourly simulations were conducted for PV-only and PV–battery configurations with different south-facing roof coverage ratios and battery capacities, together with an evacuated-tube SWH system. The results show that PV electricity supply was limited by the mismatch between household electricity demand and PV generation. Household demand mainly occurred in the morning and evening, whereas PV generation was concentrated around noon. The 13 m² PV case achieved approximately 11% electricity supply capacity with a utilization ratio of 62%, while increasing the PV area to 50 m² raised the supply capacity to only 15% and reduced the utilization ratio to 23%. With battery storage, the largest PV–battery configuration supplied 48% of annual household electricity demand, while the overall electricity utilization ratio was 73%, indicating a trade-off between household electricity self-supply and system utilization. The SWH system showed better applicability for domestic hot water supply, with an annual average hot water supply capacity of 60.2% and an average device efficiency of 43.5%, but its winter performance remained weak. These results indicate that PV and SWH are useful but insufficient solar energy strategies for passive-designed rural houses. PV is mainly constrained by daily time mismatch, while SWH is mainly constrained by seasonal climate variation. Full article

Solar photovoltaic (PV) expansion in fast-growing tropical regions requires engineering-based frameworks that compare deployment pathways in terms of electricity generation, spatial footprint, and economic performance. This study develops a techno-spatial and economic assessment of rooftop versus land-based PV deployment in a biodiversity-sensitive region of the Mexican Caribbean. The novelty lies in linking the technical, spatial, ecological, and financial dimensions of rooftop and land-based PV deployment within a single place-based framework. The framework uses a common annual electricity-output basis and integrates three modules: rooftop PV technical potential estimated from housing-census data and conservative performance assumptions; an equivalent-generation land-based PV counterfactual to estimate spatial footprint and conditional ecological exposure; and a household-scale discounted cash-flow assessment under Mexico’s subsidized residential tariff category 1C and high-consumption residential tariff (DAC, Doméstica de Alto Consumo). Under baseline assumptions, rooftop PV could provide approximately 227 megawatt-peak ($\mathrm{M}{\mathrm{W}}_{\mathrm{p}}$) of installed capacity and 330 gigawatt-hours per year ($\mathrm{G}\mathrm{W}\mathrm{h} {\mathrm{y}\mathrm{r}}^{-1}$) without additional land occupation. Producing the same output through land-based PV would require about 486 hectares ($\mathrm{h}\mathrm{a}$) and, under a forest-overlap scenario, could imply 89,600–95,300 tonnes of carbon dioxide (${\mathrm{t} \mathrm{C}\mathrm{O}}_2$) in potential conversion-related emissions. Rooftop PV showed positive economic performance under both tariffs, with stronger returns under DAC conditions. The study provides a bounded engineering-oriented comparison of PV deployment pathways rather than predictions of siting, land conversion, or adoption. Full article

Rising electricity prices, grid instability, and climate concerns are increasing the need for sustainable residential energy solutions in developing countries. This study evaluates four residential photovoltaic (PV) configurations for a household in Karachi, Pakistan, to identify a suitable option for sustainable urban energy transition and climate mitigation. The assessed systems include daytime PV with grid supply, daytime PV with 6 h battery backup and grid supply, daytime PV with full battery backup, and daytime PV with net metering. Energy requirements, installed capacity, area demand, and battery storage were calculated using household load data, while economic performance was assessed through payback period, net present value (NPV), and levelized cost of electricity (LCOE). Environmental benefits were evaluated using avoided CO₂, CH₄, and N₂O emissions, and the best-performing system was further simulated in PVsyst. Case C, comprising daytime PV with full battery backup, achieved the highest NPV of USD 25,104.3 and a payback period of approximately 4 years. Case B achieved the second-highest NPV of USD 19,183.58 while providing a more practical balance between battery backup and grid support. Case D achieved the lowest LCOE of USD 0.0307/kWh. Fully solar-dependent configurations provided the greatest emission reductions. The findings support residential PV deployment as a practical pathway for improving urban energy security and reducing climate impacts. Full article

Grid-connected photovoltaic (PV) systems paired with battery storage are becoming a core element of low-carbon distribution networks. This paper develops a complete closed-form formulation together with an independent, simulation-based verification of a single-phase grid-connected PV-battery microgrid sized for high-irradiance residential conditions in Saudi Arabia, using measured solar-resource and tariff data for Riyadh. A 6.25 kW monocrystalline array feeds a 400 V DC link through a perturb-and-observe boost stage; a bidirectional converter couples a 13.5 kWh LiFePO₄ battery; and an IEEE 1547 smart inverter interfaces a 230 V grid through an LCL filter. Governing equations for every subsystem are derived and evaluated numerically, and a Python re-implementation of the phasor power-flow model verifies the analysis over a 24 h cycle run to periodic steady state, reproducing the reference design values with a mean absolute error of 0.5%. Using measured monthly solar-resource and temperature data for Riyadh, a full twelve-month analysis gives an annual self-sufficiency of 51.8% and a PV self-consumption of 72.9% for the optimised energy-management scheme. A dedicated time-domain switching simulation with FFT analysis shows that the LCL filter limits grid-current total harmonic distortion to 0.8%, far below the L-filter value of 6.2% and below the 5% current-distortion reference of IEEE 519 (full compliance additionally requires the PCC short-circuit ratio). Twelve-month, battery-size and load-sensitivity studies confirm robustness, and a techno-economic assessment based on the Saudi Electricity Company residential tariff quantifies levelized cost, payback and battery degradation, showing that economic viability hinges on tariff reform. Full article

The practical performance of building-integrated solar systems in cold climates is strongly governed by temperature-grade matching between solar energy output and space-heating demand. However, year-round field evidence comparing solar thermal collectors, photovoltaic systems, and photovoltaic/thermal systems under the same building, climatic, and heating-network boundary conditions remains limited. This study conducted a year-round field evaluation of solar collector (SC), photovoltaic (PV), and photovoltaic/thermal (PVT) systems installed in an office building in Tianjin, China. Continuous operating data collected from November 2022 to October 2023 were used to assess seasonal thermal output, electricity generation, effective heat supply, solar utilization efficiency, carbon reduction, and payback period. During the heating season, SC exhibited the strongest direct-heating capability among the investigated systems, delivering 817.50 MJ/m² of useful heat. In contrast, under the investigated system configuration without heat-pump assistance, the outlet temperature of the PVT subsystem remained below the 45 °C direct-heating threshold, and its thermal output could not be directly utilized for winter space heating. This result is specific to the investigated operating conditions and does not exclude the potential application of PVT systems coupled with heat pumps or low-temperature heating terminals. During the non-heating season, the investigated PVT subsystem simultaneously produced electricity and usable low-temperature heat, with heat and electricity accounting for 61.3% and 38.7% of its useful output, respectively, indicating its potential for combined energy harvesting. Under the investigated climatic, system, cost, and energy-demand conditions, the entropy-weighted TOPSIS assessment ranked SC highest when non-heating-season heat demand was present, whereas PV was more suitable when such heat demand was absent. Furthermore, a demand–output matching method was developed to support SC/PV area allocation for different building types. Under the investigated climatic and energy-demand assumptions, the recommended PV area ratios were 54.5%, 67.4%, and 79.7% for residential, office, and commercial buildings, respectively. These results provide field evidence for effective heat evaluation, temperature-grade matching, and component selection in solar-assisted heating systems for cold-climate buildings. Full article

This scientific article presents a comprehensive case study detailing the design of a fully off-grid household in Poland, utilizing an energy solution that combines high-pressure hydrogen energy storage and photovoltaic (PV) technology. In response to the growing demand for sustainable and self-sufficient energy sources, the current study investigates the efficiency and yearly energy balance of this innovative system. The off-grid household is powered by a hybrid system that seamlessly integrates PV panels to harness solar energy and a high-pressure hydrogen energy storage system for long-term energy management. The presented case study examines the design and performance of a system integrating solar energy production with hydrogen storage. Through an analysis of real-world data and operational parameters, this research contributes valuable insights into the viability of such an off-grid solution in Polish environmental conditions. These findings provided an interesting approach to off-grid residential systems, offering a glimpse into the possible future of residential energetic autonomy in the pursuit of a greener and more resilient energy landscape. Full article

Amid the global drive for carbon peaking and carbon neutrality, integrating renewable energy into building energy systems to mitigate photovoltaic (PV) intermittency and realize low-carbon energy supply has become a critical research frontier. This study proposes a novel dual-storage renewable energy system integrating solar energy storage system (SES), hydrogen energy storage system (HES), and an alkaline fuel cell (AFC). The model was validated using a two-story single-family residence as the case study, with residential load profiles and Xi’an’s climatic conditions considered under real-world scenarios. An adaptive energy management strategy is developed to dynamically coordinate PV utilization, hydrogen dispatch, and grid interaction, while recovering AFC waste heat to enhance overall efficiency. Targeting minimized lifecycle cost (LCC) and levelized cost of energy (LCOE), the GenOpt multi-objective optimization model optimizes key design parameters. Key results show 74.2% annual renewable energy penetration, 68.5% carbon reduction versus conventional systems, and robust seasonal operation: PV dominates summer supply (81.3% self-sufficiency), while AFC compensates in winter (62.4% hydrogen contribution). The system reduces annual grid dependence by 43.7% with a minimum LCOE of ~12.9 USD/MWh, bridging technical feasibility and economic practicality to provide actionable insights for building-scale renewable integration. Full article

This study presents a technical assessment of solar energy systems for integrated agricultural use and rural electrification. A model village comprising 30 households was considered, and high-resolution hourly load profiles were developed to characterize consumption dynamics, including peak demand and sectoral distribution across residential, agricultural, public, healthcare, and commercial users. A 60 kW photovoltaic (PV) system was designed in conjunction with an independent solar thermal installation for hot water supply. The system configuration was established through component sizing and numerical modeling, incorporating heat transfer mechanisms and operational constraints. Time-dependent simulations performed in MATLAB (R2022b) evaluated PV power output, battery storage cycling, and thermal system performance over a 24-h horizon. A comparative analysis of standalone PV, hybrid PV/T, and decoupled PV–thermal configurations was conducted based on performance and operational criteria. The results indicate that separated electrical and thermal subsystems achieve improved cost-effectiveness, enhanced reliability, and reduced maintenance requirements. The proposed approach demonstrates the technical viability of solar-based energy systems for rural applications, supporting energy autonomy, reduced fossil fuel dependence, and sustainable agricultural development. Full article

This study investigates an integrated ecological strategy to reduce electricity consumption in semi-collective housing located in the hot–arid climate of Biskra, Algeria, a region with high solar potential. The research combines photovoltaic (PV) electricity generation with passive thermal insulation using a locally sourced bio-based material derived from date palm fibers. The case study includes 104 dwellings within a residential complex of 350 units. Results show that monocrystalline PV panels (350 W) can produce approximately 479 kWh/panel/year. To meet the total annual electricity demand (504,712 kWh), around 1052 panels are required, corresponding to 1714 m² (13.8%) of the available building envelope. This installation area demonstrates the significant photovoltaic potential of the residential complex under hot–arid climatic conditions. Thermal analysis indicates that integrating a 5 cm palm fiber insulation layer increases thermal resistance from 2.06 to 2.62 m²·°C/W and reduces heat flux from 2.18 to 1.72 W/m². This improvement decreases conductive heat transfer through the envelope by approximately 21%, while numerical simulations indicate indoor temperature reductions of 4–8 °C during summer conditions. These findings demonstrate that combining PV systems with bio-based insulation significantly enhances energy efficiency and thermal comfort in residential buildings under desert climatic conditions. Full article