Applied Solar Energy最新文献

Solar drying is a sustainable option for preserving horticultural products, but cover material strongly affects thermal behavior and drying efficiency. This work experimentally compares two identical natural-convection parabolic greenhouse solar dryers operated side-by-side in Ghardaïa (Algeria): one covered with polyethylene (PE) and the other with polycarbonate (PC). Drying kinetics were analyzed using Fick’s second law and empirical thin-layer models, effective moisture diffusivity was estimated, and internal temperatures were predicted using machine-learning models (feedforward ANN, NAR, and NARX) driven by ambient inputs. The PC-covered dryer exhibited higher internal air and absorber temperatures (by 15.5 and 18.8%, respectively) and shortened mint drying time by 68% relative to PE. The Midilli–Kucuk model best captured the drying curves, and the NARX architecture yielded the most accurate temperature forecasts (R ≈ 0.9998; MSE < 0.11). Overall, polycarbonate cladding materially enhances thermal retention and drying performance compared with polyethylene, while ANN-based prediction—especially NARX—provides reliable thermal behavior estimates that can support control and optimization of solar dryers in arid climates.

Semitransparent polymer solar cells are considered promising photovoltaic devices that can be applied to power-generating windows and facades of modern buildings and have achieved great progress in the past few years. Different from silicon-based solar cells, the optical properties of devices with organic and perovskite active layer materials can be easily tuned by modifying the chemical structure and adjusting the halide types or contents, respectively, to meet the demands of energy-generating windows. In this paper, the development progress of semitransparent polymer solar cells in terms of the selection of active layer materials, top transparent electrodes, and strategies for enhancing the performance of semitransparent polymer solar cells are introduced. Meanwhile, the challenges and outlooks for the future development of semitransparent polymer solar cells are discussed.

This study examines the evolution and advancement of solar cleaning robot technology, focusing on the development trajectory from the initial prototype to the most recent iteration. The context is set within the Middle East and North Africa (MENA) region, where the adoption of solar power initiatives is rapidly expanding. The need for efficient solar panel maintenance solutions is discussed, driven by dust and soiling accumulation challenges. The Sultanate of Oman’s ambitious renewable energy targets underscore the importance of innovative technologies like the Autonomous Solar Cleaning Robot (ASCR) in maintaining optimal photovoltaic (PV) system performance. It discusses the iterative design, functionality, and operational efficiency improvements, addressing challenges such as inaccurate brush contact and mechanical failures. The ASCR performance was tested through multiple testing and experimental conditions and was demonstrated by evaluating the solar system’s performance utilizing real-time data from irradiance, temperature, and dust sensors. The analysis performed revealed strong correlations between irradiance sensors and solar power production, with up to 100% correlation for both groups of panels. Additionally, a 90% correlation was found between the temperature readings and the power output data. The impact of dust and soiling on the solar system’s efficiency was also analyzed in this study, and a 30% energy reduction was recorded due to dust and soiling accumulation, which increasingly affects energy outcomes. Alongside the ASCR integration on the solar system, a DustIQ sensor was also integrated into the system to quantify the soiling ratios and identify the optimal cleaning interval, which, as a result, maximizes the ASCR efficiency. The findings from this study suggest that in order to ensure optimal solar panel efficiency is have an automated system responsive to real-time data generation, which helps manage dust and soiling accumulation and minimize downtime, thus ensuring more reliable renewable energy integration in the Oman region.

Nearly Zero Energy Buildings (nZEBs) are essential in sustainable construction, aiming to significantly reduce energy consumption and enhance the integration of renewable energy sources (RES). Given their critical importance in achieving global sustainability targets, this paper thoroughly reviews the existing literature on nZEBs, identifying notable gaps that may hinder their broader effectiveness and implementation. Through the application of cosine similarity and Term Frequency–Inverse Document Frequency (TF-IDF) methodologies, the exploration of research gaps in nZEBs reveals significant thematic intersections and divergences across five main research domains: renewable energy integration and optimisation; retrofitting and rehabilitation for energy efficiency; sustainable materials and technologies; analysis, optimisation, and modelling; and policy, economic, and social considerations. Demonstrating a general consensus regarding their significance, the findings indicate a high degree of thematic congruence concerning regional applicability, climate-driven optimisation, and incorporating advanced sustainable technologies. However, topics such as heat pump optimisation, ventilated roof desiccant systems, embodied energy considerations, nano-insulation technologies, and fuzzy cognitive mapping exhibit lower thematic congruence, indicating these as specialised and emerging areas that require further investigation and multidisciplinary integration. While lower cosine similarities reveal specialised and underrepresented subjects that present opportunities for future exploration, higher cosine similarities underscore critical, widely acknowledged research domains. This comprehensive examination of the subject emphasises the need for holistic, integrated strategies to achieve global sustainability objectives within the built environment while offering clear recommendations for forthcoming academic pursuits and policy formulation.

Crop yields in arched greenhouses are affected by solar energy and ambient temperature. These factors affect the temperature and heat exchange inside the greenhouse. To maintain optimum air temperature inside the greenhouse, special matrix tubes installed at different depths of the soil are used to transfer the temperature of the lower soil layers to the upper layers, thus balancing the air temperature inside the greenhouse. The study focused on the addition of phase transition materials to thermal energy accumulators. We conducted an experiment for ten days in a greenhouse with matrix tubes inside. To monitor the results, the soil was divided into 6 sections with depths of 10, 30 and 50 cm, and the height of the center of the greenhouse was 0, 30, 60, 90, 120, 150 and 180 cm. The experimental results confirm that the heat exchange device can actively regulate the thermal environment in the greenhouse. The results show that the deeper the soil, the smaller the temperature fluctuations in the soil and the more efficient the energy storage with phase transition materials. The findings indicate that heat exchangers using working fluids that can effectively improve soil temperature stability and play a role in regulating indoor air temperature through “peak shifting and valley filling”.

Photovoltaic solar power generation has shown remarkable growth. Understanding the influence of climatic factors and variables on energy production enables the development of predictive models and the assessment of generation potential across different regions. In countries such as Brazil, the availability of surface solar radiation (R_s) data can be limited, making models based on more widely available climatic variables highly relevant. The aim of this study was to use data from a conventional climatological station to develop multiple linear regression (MLR) models that are easy to implement and provide good predictive performance for estimating energy generation in a residential on-grid photovoltaic system located in Minas Gerais, Brazil. Surface radiation was estimated from sunshine duration using the Angström-Prescott model, and several climatic and derived variables were evaluated. MLR models were built and tested for their predictive ability using both daily and monthly energy generation data. Estimated R_s alone explained 81% of the variability in energy generation. The best-performing MLR models, which included R_s, sunshine duration, and Julian day, achieved an R² of 0.854. A model relying solely on the station’s native variables, without the need to calculate R_s, also showed similar performance. Compared with XGBoost, MLR models achieved comparable results while requiring fewer variables, offering greater simplicity and interpretability. The findings demonstrate the applicability of the proposed approach, particularly in regions lacking radiation data, and provide a foundation for the development of predictive models in other regions and photovoltaic systems, while also highlighting the most relevant variables.

The present study is devoted to the technoeconomic assessment of constructing a 50 MW solar photovoltaic power plant (SPPP) in the Sughd Region of the Republic of Tajikistan. In the context of growing energy deficits and decreasing availability of hydropower resources, the use of solar generation is proposed as a sustainable and economically viable solution. The study provides a comprehensive analysis of the SPP’s parameters, including site selection, technical characteristics of the equipment, performance forecasts, and the project’s financial and economic indicators. Calculations show that the use of horizontal single-axis tracker (HSAT) mounting systems reduces the nominal levelized cost of electricity (Nom LCOE) to 3.49 cents/kWh and the discounted cash flow levelized cost of electricity (DCF LCOE) to 5.08 cents/kWh, which are 7.9 and 9.1% lower, respectively, compared to fixed-tilt structures. The simple payback period for the HSAT configuration is 8 years, and the discounted payback period is 17 years, which are more favorable than the respective values for fixed-tilt systems (9 and 21 years, respectively). The results confirm the feasibility of constructing an SPPP in the Sughd Region, which will help reduce pressure on hydropower resources and enhance the region’s energy security.

This study assessed the feasibility of performing a technical and economic analysis of solar-powered irrigation systems (SPIS), electric-powered irrigation systems (EPIS), and diesel-powered irrigation systems (DPIS) for irrigating crops in different locations in Bangladesh. Twenty-two samples (twelve for the SPIS, two for the SPIS with household electrical-grid supply, four for the EPIS, and four for the DPIS) were randomly selected to assess and compare the performance of the different irrigation systems. The capacity of the solar panel varied from 4.2 to 14 kW. The study also identified the constraints of using a SPIS. Compared with SPIS and DPIS, the gross margin of various crops was greater for EPIS. On the other hand, a lower gross margin from the DPIS was obtained because there was less gross irrigated area for the production of crops. Among the case studies, the benefit-cost ratios (BCR) were 0.10 and 0.05 for SPIS and SPIS with household electrical-grid supply systems, respectively, whereas the internal rate of return (IRR) and net present value (NPV) were negative, which indicates that these irrigation systems were not economically profitable at this time. The power sources of DPIS were not found to be profitable. The DPIS induces equivalent CO₂ emissions of approximately 6% of the total agricultural land, which the SPIS can substitute. The BCR, IRR, and NPV were approximately 1.39, 44%, and USD 2369, and NPV were approximately 1.39, 44%, and USD2369 in EPIS compared with other power sources. This indicates that an EPIS with a centrifugal pump is economically viable and profitable compared with solar and diesel-powered irrigation systems for the sustainability of crop production in the current era of a changing climate.

A comparative numerical computational fluid dynamics (CFD) study is carried out to improve the design and overall performance of a locally manufactured flat-box photovoltaic (PVT) collector at low cost. The numerical study shows that the design of the solar collector in the form of a flat-box with internal blades (fins and perforated baffles) integrated with the absorber, has the maximum enhanced efficiency. The longitudinal fins increase the heat transfer area without significantly affecting the turbulence of the flow, while the transverse perforated baffles contribute to an increase of the time for the water to stay within the flat-box collector, thus increasing water temperature. Experimental assessment shows that the proposed design achieves a worthy increase in the water temperature compared to the ambient temperature. In concerning to photovoltaic (PV) module, measurements show that the temperature of the integrated PV module is higher than the temperature of the separate PV module at limited water flow of 500 mL/min. Consequently, the integrated solar module produces a reduced voltage and a reduced current. Indeed, for the limited water flow, the temperature of the absorber remains high, resulting in some heat being transferred from the absorber to the PV module and aggravated performance. In contrast, the performance of integrated PV module has been slightly improved at water flow of 1200 mL/min due to the reduction of PV module temperature. As a result, the integrated flat-box PVT systems have a critical value of water flow to improve the performance of the PV module.

A method for estimating film thickness based on the color painting of the non-absorbing film-absorbing substrate system is proposed. The method can be useful for developing the technology of applying anti-reflective coatings to solar cells. The thickness of a dark blue anti-reflective SiO film applied to a silicon wafer was determined to illustrate the method.