Search Results (127)

Steam is widely used in industry as a heat carrier for thermal processes and is primarily generated by gas-fired steam boilers. The decarbonization of industrial thermal demand relies on the capability of clean and renewable technologies to provide steam through reliable and cost-effective systems. Concentrating solar thermal technologies are attracting attention as a heat source for industrial steam generation. In addition, electricity-driven high-temperature heat pumps can provide heat using either renewable or grid electricity by upgrading ambient or waste heat to the required temperature level. In this study, linear Fresnel solar collectors and high-temperature heat pumps driven by photovoltaics are considered heat sources for steam generation in industrial processes. Energetic and economic analyses are performed across the European countries to assess and compare their performances. The results demonstrate that for a given available area for the solar field, solar thermal systems provide a higher annual energy yield in southern countries and at lower costs than heat pumps. On the other hand, heat pumps driven by photovoltaics provide higher annual energy for decreasing solar radiation conditions (central and northern Europe), although it leads to higher costs than solar thermal systems. A hybrid scheme combining the two technologies is the favorable option in central Europe, allowing a trade-off between the costs and the energy yield per unit area. Full article

The development of ultrahigh-concentration photovoltaic (UHCPV) systems plays a pivotal role in advancing sustainable solar energy technologies. As the demand for clean energy grows, the need to align concentrated photovoltaic (CPV) system design with high-efficiency solar cell production becomes critical for maximizing energy yield while minimizing resource use. Despite some experimental efforts in UHCPV development, there remains a gap in integrating Fresnel lens-based systems with the comprehensive thermal modeling of key components in improving system sustainability and performance. To bridge this gap and promote more energy-efficient designs, a detailed numerical model was established to evaluate both the thermal and optical performance of a UHCPV system. This model contributes to the sustainable design process by enabling informed decisions on system efficiency, thermal management, and material optimization before physical prototyping. Through COMSOL Multiphysics simulations, the system was assessed under direct normal irradiance (DNI) ranging from 400 to 1000 W/m². Optical simulations indicated a high theoretical optical efficiency of ~93% and a concentration ratio of 1361 suns, underscoring the system’s potential to deliver high solar energy conversion with minimal land and material footprint. Moreover, the integration of thermal and optical modeling ensures a holistic understanding of system behavior under varying ambient temperatures (20–50 °C) and convective cooling conditions (heat transfer coefficients between 4 and 22 W/m².K). The results showed that critical optical components remain within safe temperature thresholds (<54 °C), while the receiver stage operates between 78.5 °C and 157.4 °C. These findings highlight the necessity of an effective cooling mechanism—not only to preserve system longevity and safety but also to maintain high conversion efficiency, thereby supporting the broader goals of sustainable and reliable solar energy generation. Full article

Cooking food is a factor that contributes to global energy consumption and greenhouse gas emissions. This research proposes the design, simulation using thermal resistances with MATLAB Simulink, and experimental evaluation of an automated double-concentrated solar cooking system operable from inside a home. Water was used as a cooking load. Each test for 25 min was entered into a system integrated by a programmable elevator to transport the food to the roof, a configurable temperature display, a photovoltaic power source, and double solar collection (direct through a modified box oven and reflected by a parabolic dish collector). When both solar components operated simultaneously, the system reached a temperature of 79 °C, representing a 57.34 °C increase. On average, the solar concentrator provided 78.02% more energy than the oven alone. This approach is expected to reduce cooking time and contribute to sustainable home design aimed at mitigating greenhouse gas emissions. Full article

The aim of this study is to address the lack of comprehensive analysis methods for multi-functional Trombe wall systems. The objective is to establish an integrated evaluation system that assesses thermal, purification, and power generation performance. This study introduces a novel multi-objective analysis method coupling energy and exergy efficiency for three types of Trombe wall structures: traditional, thermal-catalytic (TC), and TC–photovoltaic (TC-PV). This study simultaneously monitors heat transfer, formaldehyde degradation, and photovoltaic power generation performance. A key novelty is the introduction of a quantitative index for “purification efficiency” and the revelation of the co-evolution law between PV (photovoltaic) coverage and the three types of efficiency for the first time. This study evaluates three cases: traditional, TC, and TC-PV Trombe walls. The results show that the thermal efficiencies of the three Trombe walls are 47.2%, 41.9%, and 51.7%, respectively, with corresponding thermal exergy efficiencies of 0.59%, 0.49%, and 0.63%. The TC and TC-PV Trombe walls achieve purification efficiencies of 57.0% and 53.0% and purification exergy efficiencies of 2.53% and 2.42%, respectively. The TC-PV Trombe wall has electrical and electrical exergy efficiencies of 16.0% and 12.84%, respectively. System structure optimization analysis indicates that the system achieves the best exergy efficiency when the solar irradiation is 400 W/m² and the air channel thickness is 0.05 m. Additionally, the purification exergy efficiency increases with higher formaldehyde concentrations, while thermal, purification, and electric exergy efficiencies all increase with greater PV coverage. Exergy loss analysis reveals that the TC layer and heat-absorbing plate are major sources of loss. Therefore, developing catalytic materials with high absorptivity and high catalytic activity could enhance the system’s exergy efficiency. Full article

This paper reviews recent advancements in integrated thermoelectric power generation and water desalination technologies, driven by the increasing global demand for electricity and freshwater. The growing population and reliance on fossil fuels for electricity generation pose challenges related to environmental pollution and resource depletion, necessitating the exploration of alternative energy sources and desalination techniques. While thermoelectric generators are capable of converting low-temperature thermal energy into electricity and desalination processes that can utilize low-temperature thermal energy, their effective integration remains largely unexplored. Currently available hybrid power and water systems, such as those combining conventional heat engine cycles (e.g., the Rankine and Kalina cycles) with reverse osmosis, multi-effect distillation, and humidification–dehumidification, are limited in effectively utilizing low-grade thermal energy for simultaneous power generation and desalination, while solid-state heat-to-work conversion technology, such as thermoelectric generators, have low heat-to-work conversion efficiency. This paper identifies a key research gap in the limited effective integration of thermoelectric generators and desalination, despite their complementary characteristics. The study highlights the potential of hybrid systems, which leverage low-grade thermal energy for simultaneous power generation and desalination. The review also explores emerging material innovations in high figure of merit thermoelectric materials and advanced MD membranes, which could significantly enhance system performance. Furthermore, hybrid power–desalination systems incorporating thermoelectric generators with concentrated photovoltaic cells, solar thermal collectors, geothermal energy, and organic Rankine cycles (ORCs) are examined to highlight their potential for sustainable energy and water production. The findings underscore the importance of optimizing material properties, system configurations, and operating conditions to maximize efficiency and output while reducing economic and environmental costs. Full article

The global energy demand is experiencing a rapid surge, necessitating a heightened focus on renewable energy sources for a sustainable future. Among these sources, solar energy has emerged as a promising candidate; however, it often suffers from intermittent and unreliability issues. In light of these challenges, implementing low concentrating photovoltaic (LCPV) systems presents a potential solution for enhancing solar energy utilization and improving efficiency. In the present work, a numerical investigation of the opto-thermoelectric performance of different types of V-trough-based concentrators is performed. A new Enhanced Double V-trough Concentrator (EDVC) design is proposed using COMSOL Multiphysics simulations and tested to enhance the overall efficiencies of such technology, contributing to more reliable and cost-effective solar energy harvesting. This advancement aims to support the transition toward sustainable and scalable photovoltaic solutions. The overall performance of the EDVC is compared against the existing V-trough designs, i.e., the conventional V-trough, double V-trough, and pyramidal concentrators. The numerically obtained findings show that the EDVC can achieve the highest optical efficiency and optical concentration ratio of 89% and 4.77 suns, respectively. Moreover, the short-circuit current and output power of the EDVC are higher than those of conventional designs without concentration by 488% and 450%, respectively, despite an open-circuit voltage drop of 11%. Full article

Floating photovoltaic (FPV) systems represent a promising advancement in renewable energy technology; however, a comprehensive understanding of their environmental impacts is essential. The effects of FPV installation on lake water temperature remain unclear, potentially hindering the development of the technology due to associated negative implications for aquatic ecosystems. Furthermore, the rise in water temperature associated with climate change poses additional threats to open-water bodies. In this context, the current study endeavors to develop a machine learning (ML)-based framework to assess the combined impact of climate change and the installation of FPV systems on the water quality of open-water lakes. This framework involves the creation of three predictive models and a forecasting model utilizing various ML algorithms, concentrating on temperature and water quality predictions. The framework was applied to a case study assessing the impact of installing three distinct FPV systems on the water quality of Oostvoornse Lake in the Netherlands, employing water quality data available in the literature. The findings indicate a temporal increase in both air and water temperatures at the site, underscoring the ramifications of climate change. Additionally, the results suggest that FPV installations can influence lake thermal dynamics, leading to variations in water temperature and dissolved oxygen concentration, which presents both opportunities and challenges in addressing the impacts of climate change. The proposed framework will be an effective tool for evaluating the effects of FPV systems on water quality throughout their operational lifespan while addressing significant climate change issues. Full article

This study explores the feasibility and potential of integrating dish–Stirling systems (DSSs) into multigeneration energy systems, focusing on their ability to produce both thermal and electrical energy. By leveraging the concentrated solar power capabilities of DSSs, this research examines their performance relative to alternative solutions such as photovoltaic (PV) systems and solar heating. A 25 kW Stirling Energy Systems (SES) DSS served as the basis for the analysis. Simulations were performed for local 2022 weather conditions in Germany. The study employed a detailed modeling approach using the NREL System Advisor Model (SAM) to quantify the energy outputs and evaluate the system efficiencies. The results indicate that the DSS achieved an electrical efficiency of 25% and a combined efficiency of 78% when accounting for the maximum thermal energy generated. Seasonal analysis highlights the adaptability to fluctuating energy demands, with advantages in winter heating applications. Comparative evaluations revealed DSSs as a viable cogeneration alternative to standalone PV systems and solar heaters, offering reduced environmental impacts and enhanced energy efficiency. Future work will address real-world operational conditions, including thermal storage and multigeneration integration, positioning the DSS as a sustainable solution for renewable energy generation. Full article

A photovoltaic-thermal side-absorption concentrated module (PT-SACM) based on spectrum division for photovoltaic-thermal hybrid applications is carried out. In order to reduce the absorption by materials and the axial-chromatic aberration caused by the transmissive optical system and to improve the performance of the entire system, a reflective system, the parabolic mirror array, fabricated by the ultra-precision diamond turning technology, is proposed herein. For the purposes of spectrum division, thinner volume, lightweight, and wide acceptance angle, the proposed module is designed with a diffraction optical element (DOE), a light-guide plate with a micro-structure array and a parabolic mirror array. Among them, the DOE can separate the solar spectrum into the visible band, which is converted to electrical energy via photovoltaics, and the infrared band, whose thermal energy is collected. Experimental measurements show that the overall optical efficiency of the entire system reached 38.32%, while a deviation percentage of 3.5% is calculated based on the simulation. The system has successfully demonstrated the separation of visible and infrared bands of the solar spectrum. Meanwhile, the lateral displacement between the micro-structures of the light-guide plate and the focus of the parabolic mirror array can be used to compensate for the angular deviation of the sun incidence, thereby achieving wide-angle acceptance via the proposed solar concentration system. Full article

A concentrated photovoltaic system is evaluated as a thermal energy source employing phase change material to meet the domestic water heating demand. A paraffin wax-based phase change material is selected with a 58 °C melting point to store enough thermal energy to match the hot water demand in the buildings. The energy performance of the concentrated photovoltaics containing phase change materials is compared to that of the reference to determine the increased energy outputs due to the heat removal by the material. The concentrated photovoltaics-phase change material achieved 30% higher energy output compared to the reference concentrated photovoltaic, thus providing a strong justification for the improved thermal management design. An enthalpy-based thermal model is developed to compare the experimental results with model predictions, confirming a reasonable agreement between the results. The model is used determine the optimum melting point and container size for different phase change materials under different radiation concentrations for the hot climate of the United Arab Emirates. Full article

This research addresses the need for enhanced thermal management in building-integrated photovoltaic systems, specifically focusing on semi-transparent PV panels based on luminescent solar concentrator (LSC) technology. In pursuit of optimal thermal regulation, the cooling effect of a paraffin PCM was investigated via finite element simulations developed with COMSOL Multiphysics. The PCM was thermally coupled with the PV cells situated in the frame of a south-facing window. Due to the seasonal difference between winter and summer, the PCM latent heat capacity and melting temperature were optimized to ensure the maximum nominal operating cell temperature (NOCT) reduction during summer months. PCM latent heat capacities equivalent to 120 kJ/kg, 180 kJ/kg, and 240 kJ/kg have been investigated, whereas for the melting temperature a range from 20 °C to 42 °C was spanned. The combination of higher latent heat and 36 °C melting point showed the most significant thermal benefits, by reducing the NOCT from 42 °C to 36 °C, which led to an 11.80% increase in power output across the whole PV window. Considering the same latent heat, the other melting temperature resulted in more moderate benefits, namely an enhancement of 7.88% and 3.94%, for 38 °C and 40 °C, respectively. The lower latent heat capacities resulted in an NOCT reduction that ranged between 2.7 °C and 5.3 °C, according to the associated melting point. These results testify that the presented solution could significantly enhance energy production in semi-transparent PV applications based on LSC panels. Full article

The effects of global warming are severely recognizable and, according to the OECD, 47% of the world’s population will soon live in regions with insufficient drinking water. Already, many countries depend on desalination for fresh water supply, but such facilities are often powered by fossil fuels. This paper presents an energy self-sufficient desalination system that runs entirely on solar power. Sunlight is harvested using parabolic trough collectors with an effective aperture area of 1.5 m × 0.98 m and a theoretical concentration ratio of 150 suns, in which a concentrator photovoltaic thermal (CPV-T) hybrid-absorber converts the radiation to electricity and heat. This co-generated energy runs a multi-effect distillation (MED) plant, whereby the waste heat of multi-junction concentrator solar cells is used in the desalination process. This concept also takes advantage of synergy effects of optical elements (i.e., mirrors), resulting in a cost reduction of solar co-generation compared to the state of the art, while at the same time increasing the overall efficiency to ~75% (consisting of an electrical efficiency of 26.8% with a concurrent thermal efficiency of 48.8%). Key components such as the parabolic trough hybrid absorber were built and characterized by real-world tests. Finally, results of system simulations, including fresh water output depending on different weather conditions, degree of autonomy, required energy storage for off-grid operation etc. are presented. Simulation results revealed that it is possible to desalinate around 2,000,000 L of seawater per year with a 260 m² plant and 75 m³ of thermal storage. Full article

The depletion of fossil fuels has become a significant global issue, prompting scientists to explore and refine methods for harnessing alternative energy sources. This study provides a comprehensive review of advancements and emerging technologies in the desalination industry, focusing on technological improvements and economic considerations. The analysis highlights the potential synergies of integrating multiple renewable energy systems to enhance desalination efficiency and minimise environmental consequences. The main areas of focus include aligning developing technologies like membrane distillation, pervaporation and forward osmosis with renewable energy and implementing hybrid renewable energy systems to improve the scalability and economic viability of desalination enterprises. The study also analyses obstacles related to desalination driven by renewable energy, including energy storage, fluctuations in energy supply, and deployment costs. By resolving these obstacles and investigating novel methodologies, the study enhances the understanding of how renewable energy can be used to construct more efficient, sustainable, and economical desalination systems. Thermal desalination technologies require more energy than membrane-based systems due to the significant energy requirements associated with water vaporisation. The photovoltaic-powered reverse osmosis (RO) system had the most economically favourable production cost, while MED powered via a concentrated solar power (CSP) system had the highest production cost. The study aims to guide future research and development efforts, ultimately promoting the worldwide use of renewable energy-powered desalination systems. Full article

Growing environmental concerns have driven the installation of renewable systems. Meanwhile, the continuous decline in the levelized cost of energy (LCOE), alongside the decreasing cost of photovoltaics (PVs), is compelling the power sector to accurately forecast the performance of energy plants to maximize plant profitability. This paper presents a comprehensive analysis and optimization of a hybrid power generation system for a remote community in the Middle East and North Africa (MENA) region, with a 10 MW peak power demand. The goal is to achieve 90 percent of annual load coverage from renewable energy. This study introduces a novel comparison between three different configurations: (i) concentrated solar power (parabolic troughs + thermal energy storage + steam Rankine cycle); (ii) fully electric (PVs + wind + batteries); and (iii) an energy mix that combines both solutions. The research demonstrates that the hybrid mix achieves the lowest levelized cost of energy (LCOE) at 0.1364 USD/kWh through the use of advanced transient simulation and load-following control strategies. The single-technology solutions were found to be oversized, resulting in higher costs and overproduction. This paper also explores a reduction in the economic scenario and provides insights into cost-effective renewable systems for isolated communities. The new minimum cost of 0.1153 USD/kWh underscores the importance of integrating CSP and PV technologies to meet the very stringent conditions of high renewable penetration and improved grid stability. Full article

Concentrated photovoltaic (CPV) technology is based on the principle of concentrating direct sunlight onto small but very efficient photovoltaic (PV) cells. This approach allows the realization of PV modules with conversion efficiencies exceeding 30%, which is significantly higher than that of the flat panels. However, to achieve optimal performance, these modules must always be perpendicular to solar radiation; hence, they are mounted on high-precision solar trackers. This requirement has led to the predominant use of CPV technology in the construction of solar power plants in open and large fields for utility scale applications. In this paper, the authors present a novel approach allowing the use of this technology for residential installations, mounting the system both on flat and sloped roofs. Therefore, the main components of cell and primary lens have been chosen to contain the dimensions and, in particular, the thickness of the module. This paper describes the main design steps: thermal analysis allowed the housing construction material to be defined to contain cell working temperature, while with deep optical studies, experimentally validated main geometrical and functional characteristics of the CPV have been identified. The design of a whole CPV system includes thermal storage for domestic hot water and a 1 kWh electrical battery. The main design results indicate an estimated electrical conversion efficiency of 30%, based on a cell efficiency of approximately 42% under operational conditions and a measured optical efficiency of 74%. The CPV system has a nominal electric output of 550 W_p and can simultaneously generate 630 W of thermal power, resulting in an overall system efficiency of 65.5%. The system also boasts high optical acceptance angles (±0.6°) and broad assembly tolerances (±1 mm). Cost analysis reveals higher unit costs compared to conventional PV and CPV systems, but these become competitive when considering the benefit of excess thermal energy recovery and use by the end user. Full article