Search Results (167)

Modernizing irrigation systems (ISs) from traditional gravity methods to sprinkler and drip technologies has significantly improved water use efficiency. However, it has simultaneously increased electricity demand and operational costs. Integrating photovoltaic generators into ISs represents a promising solution, as solar energy availability typically aligns with peak irrigation periods. Despite this potential, photovoltaic pumping systems (PVPSs) often face reliability issues due to fluctuations in solar irradiance, resulting in frequent start/stop cycles and premature equipment wear. The IEC 62253 standard establishes procedures for evaluating PVPS performance but primarily addresses steady-state conditions, neglecting transient regimes. As the main contribution, the current paper proposes a non-intrusive, high-resolution monitoring system and a methodology to assess the performance of an isolated, high-power PVPS, considering also transient regimes. The system records critical electrical, hydraulic and environmental parameters every second, enabling in-depth analysis under various weather conditions. Two performance indicators, pumped volume efficiency and equivalent operating time, were used to evaluate the system’s performance. The results indicate that near-optimal performance is only achievable under clear sky conditions. Under the appearance of clouds, control strategies designed to protect the system reduce overall efficiency. The proposed methodology enables detailed performance diagnostics and supports the development of more robust PVPSs. Full article

Improving the energy efficiency of residential buildings is essential for achieving global climate goals and reducing environmental impact. This study analyzes the Total Performance approach using the example of a modern semi-detached house built by a Polish developer, as an example. The building is designed with integrated systems that minimize energy consumption while maintaining resident comfort. The building is equipped with an air-to-water heat pump, underfloor heating, mechanical ventilation with heat recovery, and automatic temperature control systems. Energy efficiency was assessed using ArCADia–TERMOCAD 8.0 software in accordance with Polish Technical Specifications (TS) and verified by monitoring real-time electricity consumption during the heating season. The results show a PED from non-renewable sources of 54.05 kWh/(m²·year), representing a 23% reduction compared to the Polish regulatory limit of 70 kWh/(m²·year). Real-time monitoring conducted from December 2024 to April 2025 confirmed these results, indicating an actual energy demand of approximately 1771 kWh/year. Domestic hot water (DHW) preparation accounted for the largest share of energy consumption. Despite its dependence on grid electricity, the building has the infrastructure to enable future photovoltaic (PV) installation, offering further potential for emissions reduction. The results confirm that Total Performance strategies are not only compliant with applicable standards, but also economically and environmentally viable. They represent a scalable model for sustainable residential construction, in line with the European Union’s (EU’s) decarbonization policy and the goals of the European Green Deal. Full article

This study focuses on the optimization of valve assemblies in downhole rod pumping units (DRPUs), which remain the predominant artificial lift technology in oil production worldwide. The research addresses the critical issue of premature failures in DRPUs caused by leakage in valve pairs, i.e., a problem that accounts for approximately 15% of all failures, as identified in a statistical analysis of the 2022 operational data from the Uzen oilfield in Kazakhstan. The leakage is primarily attributed to the accumulation of mechanical impurities and paraffin deposits between the valve ball and seat, leading to concentrated surface wear and compromised sealing. To mitigate this issue, a novel valve assembly design was developed featuring a flow turbulizer positioned beneath the valve seat. The turbulizer generates controlled vortex motion in the fluid flow, which increases the rotational frequency of the valve ball during operation. This motion promotes more uniform wear across the contact surfaces and reduces the risk of localized degradation. The turbulizers were manufactured using additive FDM technology, and several design variants were tested in a full-scale laboratory setup simulating downhole conditions. Experimental results revealed that the most effective configuration was a spiral plate turbulizer with a 7.5 mm width, installed without axis deviation from the vertical, which achieved the highest ball rotation frequency and enhanced lapping effect between the ball and the seat. Subsequent field trials using valves with duralumin-based turbulizers demonstrated increased operational lifespans compared to standard valves, confirming the viability of the proposed solution. However, cases of abrasive wear were observed under conditions of high mechanical impurity concentration, indicating the need for more durable materials. To address this, the study recommends transitioning to 316 L stainless steel for turbulizer fabrication due to its superior tensile strength, corrosion resistance, and wear resistance. Implementing this design improvement can significantly reduce maintenance intervals, improve pump reliability, and lower operating costs in mature oilfields with high water cut and solid content. The findings of this research contribute to the broader efforts in petroleum engineering to enhance the longevity and performance of artificial lift systems through targeted mechanical design improvements and material innovation. Full article

Global building energy consumption is significantly increasing. Utilizing renewable energy sources may be an effective approach to achieving low-carbon and energy-efficient buildings. A combined system incorporating solar photovoltaic–thermal (PV/T) components with an air-source heat pump (ASHP) was studied for simultaneous heating and power generation in a real residential building. The back panel of the PV/T component featured a novel polygonal Freon circulation channel design. A prototype of the combined heating and power supply system was constructed and tested in Fuzhou City, China. The results indicate that the average coefficient of performance (COP) of the system is 4.66 when the ASHP operates independently. When the PV/T component is integrated with the ASHP, the average COP increases to 5.37. On sunny days, the daily average thermal output of 32 PV/T components reaches 24 kW, while the daily average electricity generation is 64 kW·h. On cloudy days, the average daily power generation is 15.6 kW·h; however, the residual power stored in the battery from the previous day could be utilized to ensure the energy demand in the system. Compared to conventional photovoltaic (PV) systems, the overall energy utilization efficiency improves from 5.68% to 17.76%. The hot water temperature stored in the tank can reach 46.8 °C, satisfying typical household hot water requirements. In comparison to standard PV modules, the system achieves an average cooling efficiency of 45.02%. The variation rate of the system’s thermal loss coefficient is relatively low at 5.07%. The optimal water tank capacity for the system is determined to be 450 L. This system demonstrates significant potential for providing efficient combined heat and power supply for buildings, offering considerable economic and environmental benefits, thereby serving as a reference for the future development of low-carbon and energy-saving building technologies. Full article

Hydropressor systems are of paramount importance in keeping water supplies running properly. A typical such device consists of two (or more) identical electropumps operating alternately, so as to avoid downtime as much as possible. We consider a dual pump configuration to identify the ideal usage proportion of each pump (from 0%-100%, meaning interchange only upon failure, to 50%-50%, where each pump works half the time) in order to improve availability, accounting solely for corrective maintenance. We also address the possibility of improving the availability of a single pump under the hazard of failure in three different ways (with their own occurrence frequencies), while also accounting for preventive maintenance. Both settings are tackled through Monte Carlo simulation and the models are implemented with the Python 3.12 programming language. The results indicate that significant improvements to standard industry practices can be made. Full article

The management of municipal solid waste remains a critical environmental and energy challenge across the European Union (EU), where a significant portion of waste still ends up in landfills, generating landfill gas (LFG) rich in methane and harmful impurities. In Latvia, despite national strategies to enhance circularity, untreated LFG is underutilized due to inadequate purification infrastructure, particularly in meeting biomethane standards. This study addressed this gap by proposing and evaluating an innovative, multistep LFG purification system tailored to Latvian conditions, with the aim of enabling the broader use of LFG for energy cogeneration and potentially biomethane injection. The research objective was to design, describe, and preliminarily assess a pilot-scale LFG purification prototype suitable for deployment at Latvia’s largest landfill facility—Landfill A. The methodological approach combined chemical composition analysis of LFG, technical site assessments, and engineering modelling of a five-step purification system, including desulfurization, cooling and moisture removal, siloxane filtration, pumping stabilization, and activated carbon treatment. The system was designed for a nominal gas flow rate of 1500 m³/h and developed with modular scalability in mind. The results showed that raw LFG from Landfill A contains high concentrations of hydrogen sulfide, siloxanes, and volatile organic compounds (VOCs), far exceeding permissible thresholds for biomethane applications. The designed prototype demonstrated the technical feasibility of reducing hydrogen sulfide (H₂S) concentrations to <7 mg/m³ and siloxanes to ≤0.3 mg/m³, thus aligning the purified gas with EU biomethane quality requirements. Infrastructure assessments confirmed that existing electricity, water, and sewage capacities at Landfill A are sufficient to support the system’s operation. The implications of this research suggest that properly engineered LFG purification systems can transform landfills from passive waste sinks into active energy resources, aligning with the EU Green Deal goals and enhancing local energy resilience. It is recommended that further validation be carried out through long-term pilot operation, economic analysis of gas recovery profitability, and adaptation of the system for integration with national gas grids. The prototype provides a transferable model for other Baltic and Eastern European contexts, where LFG remains an underexploited asset for sustainable energy transitions. Full article

The short-term scheduling of pumped-storage hydropower plants is characterised by high dimensionality and nonlinearity and is subject to multiple operational constraints. This study proposes an intelligent scheduling framework that integrates an Atomic Orbital Search (AOS)-optimised Long Short-Term Memory (LSTM) network with the Deep Deterministic Policy Gradient (DDPG) algorithm to minimise water consumption during the generation period while satisfying constraints such as system load and safety states. Firstly, the AOS-LSTM model simultaneously optimises the number of hidden neurons, batch size, and training epochs to achieve high-precision fitting of unit flow–efficiency characteristic curves, reducing the fitting error by more than 65.35% compared with traditional methods. Subsequently, the high-precision fitted curves are embedded into a Markov decision process to guide DDPG in performing constraint-aware load scheduling. Under a typical daily load scenario, the proposed scheduling framework achieves fast inference decisions within 1 s, reducing water consumption by 0.85%, 1.78%, and 2.36% compared to standard DDPG, Particle Swarm Optimisation, and Dynamic Programming methods, respectively. In addition, only two vibration-zone operations and two vibration-zone crossings are recorded, representing a reduction of more than 90% compared with the above two traditional optimisation methods, significantly improving scheduling safety and operational stability. The results validate the proposed method’s economic efficiency and reliability in high-dimensional, multi-constraint pumped-storage scheduling problems and provide strong technical support for intelligent scheduling systems. Full article

Air–water heat pumps are gaining interest in modern architectures, and they are a suitable option as a replacement for fossil fuel-based heating systems. These systems consume less electricity by combining solar panels, a heat pump, thermal storage, and a smart control system. This study was applied to a completely ecological rural health sub-center built on the basis of recycled bottles, and that, for its regular operation, requires an energy system according to the needs of the patients in the rural community. Detailed analyses were performed for heating and hot water preparation in two scenarios with different conditions (standard and fully integrated). From a technical perspective, different strategies were analyzed to ensure its functionality. If the photovoltaic system is sized to achieve advanced control, the system can even operate autonomously. However, due to the need to guarantee the energy efficiency of the center, the analyses were performed with a grid connection, and it was determined that the photovoltaic system guarantees at least two-thirds of the energy required for its autonomous operation. The results show that the system can operate normally thanks to the optimal size of the photovoltaic system, which positively influences the rural population in the case under analysis. Full article

Rapid suburbanization can alter catchment flow regime and increase stormwater runoff, posing threats to sensitive ecosystems. Applications of Nature-based Solutions (NbS) have increasingly been adopted as part of integrated water management efforts to tackle the hydrological impact of urbanization with co-benefits for improved urban resilience, sustainability, and community well-being. However, the implementation of NbS can be hindered by gaps in performance assessment. This paper introduces a physically based dynamic modeling approach to assess the performance of a nature-based storage facility designed to capture excess runoff from an urbanizing catchment (Armstrong Creek catchment) in Geelong, Australia. The study adopts a numerical modelling approach, supported by extensive field monitoring of water levels over a 2.5-year period. The model provides a decision support tool for Geelong local government in managing stormwater runoff to protect Lake Connewarre, a Ramsar-listed wetland under the Port Phillip Bay (Western Shoreline) and Bellarine Peninsula. Runoff is currently managed via a set of operating rules governing gate operations that prevents flows into the ecological sensitive downstream waterbody from December to April (drier periods in summer and most of autumn). Comparison with observed water level data at three monitoring stations for a continuous simulation period of May 2022 to October 2024 demonstrates satisfactory to excellent model performance (NSE: 0.55–0.79, R²: 0.80–0.89, ISE rating: excellent). Between 1670 × 10³ m³ and 2770 × 10³ m³ of runoff was intercepted by the nature-based storage facility, representing a 56–70% reduction in stormwater discharge into Lake Connewarre. Our model development underscores the importance of understanding and incorporating user interventions (gate operations and emergency pumping) from the standard operation plan to better manage catchment runoff. As revealed by the seasonal flow analysis for consecutive years, adaptive runoff management practices, capable of responding to rainfall variability, should be incorporated. Full article

Background: Over the past decade, Shanghai primary and middle schools have installed and updated direct-drinking water facilities in compliance with local policies, but few studies have assessed the schools providing direct-drinking water access. Methods: A cross-sectional study was conducted with 167 public primary, middle, and high schools across Pudong New Area, Shanghai during Autumn 2024. The type, location, and working condition of all direct-drinking water facilities throughout each school were documented by trained research staff using a direct observation protocol. Information on school direct-drinking water quality was obtained from the routine monitoring program. Data were analyzed for comprehensive assessment of direct-drinking water facilities in the schools. Results: On average, each school had one faucet of direct-water facility per 41 students; 70% of the schools met the requirement for minimum direct-drinking water access, and >90% placed facilities in high-traffic areas. In addition, 83% of the schools selected water facilities with nanofiltration and a hot water system, and most only provided hot water (above 50 degrees Celsius). For school direct-drinking water quality, the concentrations of hardness, chemical oxygen demand (COD), and total dissolved solids (TDS), as well as pH values, were improved significantly, but the total bacteria count was prone to not meeting the requirement for standards in middle and high schools, which could be caused by insufficiency of chlorination in pumping stations or neglecting to clean facilities promptly. Conclusions: Wide usage of school direct-drinking water facilities could help most public schools to meet local policies for minimum student drinking water access in Shanghai, but microbial contamination was the potential threat. Water temperature is the key factor affecting students’ drinking water, providing an optional water temperature for students’ preferences and concerns. National sanitary standards of direct-drinking water quality and relevant additional regulations should be established and implemented in China. Full article

This study investigates the relative benefits of solar thermal (ST) and photovoltaic (PV) systems integrated with air-source heat pumps for domestic hot water production in newly built residential buildings. Using calibrated DesignBuilder simulations of “The Future Home” located in Energy House 2.0, an environmental chamber, the study analyzes energy performance and carbon emissions for eight scenarios: (1) baseline heat pump only, (2) heat pump with 4 m² PV panels, (3) heat pump with 4 m² ST panels, (4) heat pump with 2 m² PV + 2 m² ST panels, and (5–8) variants with increased hot water demand. While ST systems directly heat water through thermal energy transfer, PV systems contribute to water heating indirectly by providing electricity to power the heat pump. The results show that the ST system provides 964.6 kWh of thermal energy annually, increasing to 1528 kWh with enhanced hot water demand, while a similarly sized PV system generates 532.5 kWh of electricity. The research reveals that Standard Assessment Procedure methodology’s fixed hot water demand assumptions could significantly underpredict solar thermal benefits, potentially discouraging UK house builders from adopting this technology. Full article

The present work addresses the critical challenge of assessing building facade watertightness against wind-driven rain, a major threat to structural integrity and durability. The current evaluation methods rely heavily on standardized test outcomes, neglecting a disconnect between test conditions and real-world exposure, leading to subjective judgments. To bridge this gap, this paper developed a quantitative method linking key inspection parameters (pump pressure, water spray distance) to wind-driven rain characteristics (wind speed, rainfall intensity) in the Shanghai area using statistical return periods. The calculation process encompasses regression models that correlate extreme rainfall and wind velocity values over sub-daily intervals, as well as a method for extrapolating maximum wind velocities using wind data coinciding with rainfall events. This approach enables specification-compliant performance assessment and tailored inspection protocols, such as JGJ/T 299, EN 12155, and ASTM E547. Applied to two Shanghai buildings, the method demonstrated a robust framework for translating environmental data into actionable inspection criteria. The results show a direct correlation between test parameters and extreme weather statistics. For instance, the watertightness performance of an old building is quantitively assessed as a return period of 1.02 years, while a new office building aiming for 50-year waterproofing could be inspected at a pump pressure of 900 kPa and a spraying distance of 0.15 m using the proposed method. This paper offers a data-driven alternative to empirical assessments, enhancing reliability in facade design and regulatory compliance, and provides a scientific basis for decision-making in building maintenance and renovation. Full article

The increasingly severe energy crisis and associated environmental issues pose new challenges for the efficient and rational utilization of renewable energy. The solar-assisted ground-source heat pump (SAGSHP) system is a novel heating system that effectively combines the advantages of both solar and geothermal energy. In this study, an SAGSHP system was established through TRNSYS simulation software to provide winter heating and year-round domestic hot water for a residential building. By varying the area of solar collectors (A) and the number (n) and the depth (H) of the borehole heat exchangers (BHEs), the system operational performance, including the system energy consumption, ground temperature attenuation, and heat pump efficiency, was investigated. A comparison with a single ground-source heat pump (GSHP) system was also conducted. After 20 years of operation, the parameter optimization resulted in a reduction of approximately 60 MWh and 70 MWh in system energy consumption, equivalent to saving 7.37 t and 8.60 t of standard coal, respectively. At the same time, the total costs over 20 years can be reduced by 48.20% and 33.77%, respectively. The proposed design method and simulation results can serve as the reference for designing and analyzing the performance of the SAGSHP system. Full article

In the present paper, the idea of regulating the vacuum level by means of a variable frequency drive (VFD) in order to control the speed of the vacuum pump of a milking system was considered. Wet tests (using water instead of milk) were performed in order to tune the PID controller, which drives the VFD; then, the virtual instrument built using the LabVIEW environment was adapted in order to regulate the vacuum level as a function of the flow rate. The system was tested in order to verify vacuum stability and system response time. Wet tests have proven that the vacuum level in the system was affected by presence of the liquid column in the milk line; as a result, the standard deviation of the vacuum level was comprised between 0.067 kPa and 1.43 kPa (depending on the flow rate and vacuum level), while in the previous dry tests the standard error was comprised between 0.186 kPa and 0.194 kPa. Nevertheless, vacuum fluctuations did not exceed the imposed limit of ±2 kPa relative to the nominal vacuum in the flow-controlled vacuum system. In order to reduce the vacuum fluctuations, the original claw of the installation was replaced with a larger one, with a volume of 330 cm³; under these conditions, the standard deviation of the vacuum level decreased to 0.134–0.288 kPa. Full article

Energy efficiency represents a strategic priority in both Italian and European legislation to mitigate the energy consumption of buildings, which are significant contributors to greenhouse gas emissions. Currently, about 75% of the EU building stock is considered to be energy inefficient and requires substantial retrofitting. This study examines the energy redevelopment of a large building complex, which currently has an energy class E label. The aim is to achieve a significant improvement in energy efficiency and reduce fossil fuels usage, in line with sustainability standards. The intervention includes replacing the existing air-conditioning and heating systems with high-efficiency air-to-water heat pumps, powered by electricity generated, in part, by an integrated photovoltaic system. Through the analysis of available technological solutions and the application of a Building Information Modeling (BIM) methodology, the research proposes strategies to optimize the energy efficiency of buildings while minimizing the environmental impact and ensuring compliance with current regulations. The results highlight the effectiveness of such approaches in supporting the energy transition, with the implemented measures reducing the non-renewable energy demand from 191,684 kWh/m²/year to 76,053 kWh/m²/year. This led to a decrease in CO₂ emissions of 604 tons/year, representing a 78% reduction compared to initial levels, a clear contribution toward achieving European sustainability goals. Full article