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[Display omitted] • Various carbon nanotube-based devices are developed for solar energy utilization. • The water evaporation system can generate freshwater (1.28 kg m−2h−1). • The solar-thermoelectric system can output a voltage and charge a cellphone. • The supercapacitor performs an areal specific capacitance of 19.6 mF cm−2. • The hybrid energy system can produce freshwater, generate and store electric power. Nowadays, multi-functional systems driven by solar energy have been explored to alleviate the crisis of energy and freshwater scarcity. However, it remains a great challenge to integrate multi-functions into one hybrid system with a monolithic material, which can harvest, convert and store solar energy synergistically. Here, we firstly propose a multi-functional carbon nanotube paper, which starts from a material level to solve these problems. The carbon nanotube paper is fabricated by vacuum filtration. It exhibits high efficiency of solar-thermal conversion. Secondly, three types of energy conversion/storage systems (e.g., solar-thermal evaporation system, solar-thermoelectric generation system, and supercapacitor) are constructed based on the carbon nanotube paper, which extend the research to a device level. The solar-thermal evaporation system shows an evaporation rate of 1.28 kg m-2h−1 under simulated sunlight irradiation of 1 kW m−2. The solar-thermoelectric generation system demonstrates a stable electric power generation with an output voltage of 100 mV under light irradiation of 1 kW m−2. The supercapacitors perform the energy storage function with an areal specific capacitance of 19.6 mF cm−2. These devices and systems can be used in freshwater generation (0.84 kg m-2h−1, sunlight irradiation of 1 kW m−2), water purification/desalination (inorganic ions rejection larger than 99.9%) and portable solar charging system (maximum output voltage of 5 V). Finally, a hybrid energy system is innovatively proposed from the system level to simultaneously produce freshwater, generate and store electric power. Through the synergetic coupling of solar conversion and storage technologies, the hybrid energy system can supply sustainable freshwater and electricity for remote areas in daily life, highlighting the superiority of multi-energy (thermal energy, electrical energy, and electrochemical energy) complementary. [ABSTRACT FROM AUTHOR]

Design of hybrid Nano-Grid system (HNGS) necessitates a careful thought to benchmark reliable and cost effective solutions for remote areas. Optimal sizing of HNGS using Honey Badger Algorithm (HBA) for futuristic residential area in Mahendragarh, Haryana, India is presented in this paper. The HNGS comprise combination of solar panels, wind turbines, storage batteries, diesel generator, inverter and residential load components. The primary objective functions considered in this paper are Cost of Electricity (COE) and Net Present Cost (NPC), in continuation these problems are stated as multi objective optimization issues. Numerous permutations of diverse resources were examined to assess parameters such as NPC, COE, battery storage, land utilization, emission and potential employment opportunities. HBA is almost independent of traps in the local minimum, therefore the results obtained are superior as compared with Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Biogeography Basic Optimization (BBO), Improved Artificial Ecosystem Optimization (IAEO) and Grey Wolf Optimization (GWO) as well as HOMER software, in order to determine the quality of solution the proposed HBA algorithm has obtained. HNGS system can be readily and efficiently optimized using the suggested HBA algorithm a detailed sensitivity analysis is done to better understand the system behavior for a wider region use. • A well optimized HNGS design is cost-effective, highly reliable and simple system for remote areas. • An optimization problem is formulated and solved by means of Honey Badger algorithm. • The optimization aim is to find HNGS size in terms of number of individual sources which supplies demand successfully. • Outcomes show that HBA effectively optimizes HNGS by lowering the NPC and CoE, ensuring the electricity supply. • The HBA's results has been compared to GA, PSO, BBO, IAEO, and GWO, as well as HOMER software. • Sensitivity analysis has been used to explore the impact of weather and component parameters on COE and NPC. [ABSTRACT FROM AUTHOR]

• Proposed a novel advanced solar-driven combined heat and power system. • Constructed the overall heat current model and exergy analysis expression. • Analyzed the exergy loss and efficiencies of each component and the system. • Analyzed the influences of various parameters on the system exergy efficiency. Conducting research on advanced cycle of distributed energy system and improving energy utilization efficiency is an important approach to promote the development of distributed energy systems. The paper proposed a novel solar-driven supercritical carbon dioxide-heat pump cogeneration system based on solar power tower system and performed the overall modeling of the system using the heat current method. The overall exergy loss calculation model of the system was established by applying the exergy analysis method incorporating the standard thermal resistance-based entropy generation rate expression. The calculation results present that under rated condition, irreversible loss mainly occurs in the solar energy conversion part, accounting for 73.83 %, and the system exergy efficiency is 34.69 %. Besides, the paper investigated the steady state performance of the system under different working conditions and the influence of the turbine inlet temperature and the intermediate pressure on the system performance. When the direct normal irradiance increases, the proportion of exergy loss in solar energy conversion part increases by 62.13 %, while the change of system exergy efficiency depends on the operating state of the system. The optimum intermediate pressure is 11.72 kPa, when the net power output and the exergy efficiency of the whole system reaches the maximum. Finally, the proposed system contributes to the improvement of cascade utilization of energy, and the modeling method is effective for solar-driven supercritical carbon dioxide cogeneration systems. [ABSTRACT FROM AUTHOR]

• The thermal, rheological, and optical properties of ferrofluids and how they change with magnetic fields were discussed. • The utilization of ferrofluids in solar energy systems was detailed in a state-of-the-art analysis. • The recommendations aimed to optimize the use of ferrofluids and magnetic fields in energy systems to enhance performance. Solar energy technologies play a crucial role in the transition to sustainable energy sources; however, there is an ongoing challenge in optimizing their efficiency and performance. This review paper thoroughly exposes the potential for enhancing solar systems by incorporating ferrofluids and utilizing magnetic fields. It provides a comprehensive examination of the rheological, thermal, and optical properties of ferrofluids, as well as their behavior when exposed to magnetic fields. The paper emphasizes the ability of ferrofluids to improve heat transfer efficiency, adapt to changing conditions, and enable precise control in the conversion of solar energy. Furthermore, the review addresses the obstacles and limitations associated with integrating ferrofluids into solar technologies, proposing potential solutions and outlining future research directions. [ABSTRACT FROM AUTHOR]

• A novel photovoltaic-thermal vapor injection heat pump is raised. • The operation characteristics of the novel system are analyzed by simulation method. • 4E performance of the novel and economized vapor injection heat pump are compared. • The novel system owns obvious performance improvement over convenient system. A novel photovoltaic-thermal vapor injection heat pump (PVHP) is proposed and analyzed in this paper, which owns remarkably superior performance by realizing cogeneration of electricity and thermal energy from solar energy. The operation characteristics of PVHP are evaluated based on built simulation model. It indicates that the solar assisted mode is suitable for extremely low or no solar radiation conditions, while the vapor injection mode is preferable to other conditions. There exists optimal combination of intermediate pressure and split ratio for PVHP to achieve the maximal comprehensive COP (coefficient of performance). The energy, exergy, economic and environmental performance of PVHP and traditional economized vapor injection heat pump (VIHP) are compared based on genetic algorithm. Thereinto, the heating COP and comprehensive COP of PVHP respectively exceed the heating COP of VIHP by averages of 18.4 % and 4.1 % under evaporating temperature range of −20 ∼ 5 °C. Moreover, PVHP can produce 4.2 % more heat exergy output with 12.2 % less net electricity consumption compared with VIHP. PVHP yields about 8.5 years payback periods in four northern China cities when adopted to replace VIHP in the considered application scenario, and significantly reduces the pollutant emissions. In addition, the optimal combination of comprehensive COP and levelized cost of energy is located at [5.55, 0.132 $ kWh−1] by multi-objective optimization. [ABSTRACT FROM AUTHOR]

• Synergistically manage the operation of hydro-photovoltaic (HPV) power systems. • Develop a mission chain-based performance efficiency model of HPV power systems. • Quantify the capacity of the power supply mission fulfilment to satisfy the power demand. • Propose an importance measure-based restoration strategy to optimise the HPV performance. • Give a large-scale hydro-photovoltaic plant in China in winters and summers. Synergistically and complementarily managing the operation of hydropower plants and other weather-dependent renewable energy generation plants (e.g., solar energy plants) provides an effective measure to improve the performance efficiency (PE) of renewable energy. However, environmental uncertainty and physical system unavailability pose challenges in assessing the PE of the power generation. This paper proposes an approach to synergistically and complementarily managing the operation of hydro-photovoltaic (HPV) power systems in IoT under uncertain environments and develops a mission chain-based PE model for quantifying the capacity of the fulfilment of a power supply mission to satisfy users' demand for power. An importance measure-based restoration strategy is then proposed to enhance the PE of an HPV power system (PEPS). The approach is examined by taking a large-scale HPV in China in the case study. The results show that, in winters and in summers, the PEPS is higher than PE of a photovoltaic power system and a hydropower system, respectively, and the PEPS with the importance measure-based restoration strategy is higher than that under the random restoration strategy, respectively. The findings not only lay the foundation for the complementary operation of hybrid renewable energy power systems but also provide a reference for the restoration in case of power cuts. [ABSTRACT FROM AUTHOR]

Due to the inherent variability of the power output of offshore wind farms, their integration into electrical grids poses a challenge to their stability and leads to significant balancing costs. Combining wind and solar power may be expected to mitigate the power output variability. In addition, a number of synergies can be realised—shared infrastructure, shared crews and vessels for operations and maintenance, and last but not least, optimum use of scarce marine space. The objective of this work is to investigate this hybrid approach and, in particular, to determine the optimum capacity of the solar energy subsystem given a certain installed capacity of the wind energy subsystem. Three case studies are considered in Europe and China. Each of them is an existing wind farm that could be retrofitted with floating solar PV. After assessing the local wind and solar energy resources, the optimal size of the floating solar array is calculated with a view to smooth the aggregated power output of each farm. Subsequently, the benefits of this hybrid approach are demonstrated from various perspectives. It is found that a much larger solar array is required for a wind farm with a large installed capacity, but the specific optimal size depends more on the local wind and solar resources. The novelty of this paper lies in its exploration of retrofitting existing offshore wind turbines with floating solar PV systems from the perspective of addressing the variability challenge for the currently operating wind farms. This study could serve as a guideline for project designs aiming to retrofit existing offshore wind farms with solar PV technology, thus reducing balancing costs and facilitating the penetration of offshore renewable energy into national power grids. [Display omitted] • Reduced power output variability through hybrid offshore wind–solar farms. • Three offshore wind farms in Europe and China selected for retrofitting with solar PV. • Optimum capacity of solar energy subsystem for minimum power variability. • Differences between the three farms in Europe and China due to resources. [ABSTRACT FROM AUTHOR]

Highlights • Comprehensive review on heat transfer, device design and limitation of Concentrated Photovoltaic Thermal system. • Component wise thorough discussion on design and limitations of Concentrated Photovoltaic Thermal system. • Discussion on economic feasibility and recent novel applications of Concentrated Photovoltaic Thermal system. • Presents recent trends and move in Concentrated Photovoltaic Thermal system research. Abstract The need of the hour in present world scenario is to reduce the emission of greenhouse gases and environmental pollution whilst satisfying the world energy demands. The most promising and readily available source of energy over the whole world is solar energy. One of the ways of taping this energy into useful energy is using Concentrated Photovoltaic Thermal systems. The paper presents the advanced comprehensive review on the design components of Concentrated Photovoltaic Thermal, heat transfer medium, recent application area such as Tissue Dyeing, domestic hot water, Organic Rankine Cycle, and the economic aspect of the Concentrated Photovoltaic Thermal system. Furthermore, the review paper simplifies the classification into two systems namely thermally coupled and thermally decoupled systems. Concentrated Photovoltaic Thermal shows potential to deliver better gains compared to Concentrated Photovoltaic, Photovoltaic and Photovoltaic Thermal. But matching the different components like the heat transfer component and the medium for specific use is an area that requires research. Therefore, this review concentrates more on the advantages and limitations of using different heat transfer components and heat transfer medium. The benefits of this paper would be the understanding of the components of the heat transport system like fins, microchannel, storage tank and underground heat exchangers and the fluid used in the Concentrated Photovoltaic Thermal integrated system like water, air, nanofluids, Phase Change Materials. It is found that the heat transfer device performance is limited due to its large area, thermal losses, mirror effect on the thermal and electrical efficiencies, and the temperature difference between the sink and device. Likewise, the performance of the heat transfer fluid is dependent on the mass flow rate, thermal mass, viscosity, density, time and the required temperature. Finally, for economic feasibility of the Concentrated Photovoltaic Thermal system requires the need for a grid connected system with properly sized system with feed-in-tariff and carbon incentives. Furthermore, the recommendation for heat transfer device, medium and economic aspect is also presented. However, more experimental research is required to further understand the compatibility of each components with Concentrating Photovoltaic Thermal System as presented in way forward. [ABSTRACT FROM AUTHOR]

Highlights • A background of HPSCs, their principles of operation, modelling, and applications. • A comprehensive review of strategies to enhance the performance of HPS systems. • Identification of research gaps and recommendations for future research potentials. Abstract Invention of evacuated tube heat pipe solar collectors (HPSCs) was a huge step forward towards resolving the challenges of conventional solar systems due to their unique features and advantages. This has led to their utilization in a wide range of solar applications surpassing other conventional collectors. However, relatively low thermal efficiency of heat pipe solar (HPS) systems is still the major challenge of solar industry evidenced by numerous studies conducted mainly during the last decade to improve their efficiency. To date, several review papers have been published summarizing studies relevant to utilization of HPSCs in various thermal applications. However, to the authors' knowledge, a comprehensive review which surveys and provides an overview of the studies undertaken to improve the thermal performance of HPS systems (mainly during the last decade) by implementing different strategies has not been published to date. This review paper summarizes all the proposed strategies to improve the thermal efficiency of different industrial, domestic, and innovative HPS systems. First, the concept, structure, and operational principles of HPSCs are introduced concisely. Then, novel structures and designs of HPSCs aiming to increase the thermal efficiency of the collector as the most important component of the solar system is reviewed. This is followed by a comprehensive review of various methods to store solar energy more efficiently, increase solar system's operation time, increase overall efficiency by turning the solar system into a multi-purpose system, enhance heat transmission in the solar system, and implement new solar loop and heat pipe working fluids with better heat transfer characteristics. Finally, research gaps in this field are identified and some future research trends and directions are recommended. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes a solar-assisted combined power and cooling (SCPC) system. • Cascade utilization of natural gas and solar energy has been established. • Thermal efficiency of the SCPC system is 70.35% with renewable energy ratio of 18.1%. • Two different cooling temperature levels are achieved in the same system. • Key parameters were investigated to provide guidance to the system optimization. Abstract Distributed energy system has received increasing attention nowadays because of its great advantages on utilizing waste heat in cascade and renewable energy flexibly. This paper proposed a solar-assisted combined power and cooling system (SCPC) which supplies power and cooling capacity at two different temperature levels for a cold storage. The cogeneration system is composed of an internal combustion engine, evacuated tube collectors, a heat storage tank and an ammonia-water combined power and cooling system. The exhaust gas of the internal combustion engine is used to generate superheated ammonia-water vapor in the ammonia-water power generation subcycle. The jacket water waste heat is recovered and assisted by the solar collector field to drive the absorption-compression subcycle. Simulation work of the proposed system was conducted, and its performance was analyzed and evaluated from the aspects of energy and exergy. Thermal efficiency of the SCPC system is 70.35% with the renewable energy ratio of 18.1%, and its exergy efficiency is 45.52%. Combined with the coefficient of exergy destruction, average energy level difference was proposed and defined to analyze the energy saving mechanism and further improvement potential of the proposed system. The effects of key parameters including turbine inlet pressure and generation pressure in low-pressure reboiler at different condensation/absorption temperatures have been investigated, providing guidance for the system's optimal design. [ABSTRACT FROM AUTHOR]

Highlights • Focus on a thermal storage wind-concentrated solar power hybrid system. • A capacity configurations optimization method for the hybrid system is proposed. • The effects of the key parameters on the performances of the system are revealed. • Integrating the electric heat could significantly reduce the wind curtailment. • The stability of the output power is improved by integrating electric heater. Abstract In order to reduce wind curtailment, a wind-turbine coupled with a solar thermal power system to form a wind-solar hybrid system is proposed in this paper. In such a system, part or all of the curtailed wind power is turned into heat through an electric heater and stored in the thermal storage sub-system of the solar thermal power plant. To simulate and study the performance of the hybrid system, a simulation model of the hybrid system, which consists several modules/sub-models is developed. In addition, a capacity configurations optimization model based on particle swarm optimization algorithm is proposed to maximize the economic performance. An 80 MWe hybrid system in Zhangbei China is selected as the study case. The result shows that when the capacity ratio of the wind power generation to solar thermal power generation, thermal energy storage system capacity, solar multiple and electric heater capacity are 1.91, 13 h, 2.9 and 6 MW, respectively, the hybrid system has the highest net present value of $27.67 M. Correspondingly, compared to the conventional coal-fired power plant, it could reduce carbon dioxide emission by 15,470 tons per year. Besides, the sensitivity of each capacity parameter on the annual performances of hybrid system is analyzed in this paper. The results show that the electric heater can effectively reduce the wind curtailment and improve the overall system stability. The results also show that the hybrid system with bigger thermal storage system capacity and smaller solar multiple has better performance in reducing wind curtailment. And when the solar multiple is constant, mean power change rate decreases with the increase of thermal storage system capacity. The bigger the solar multiple is, the faster the decrease of mean power change rate is. [ABSTRACT FROM AUTHOR]

Graphical abstract System output power along with solar irradiance and SWP power. Highlights • Isolated continuous power generation system at constant voltage using solar energy. • A novel technique using PHES with solar photovoltaic system for reliable and quality power. • Power generation absolutely unaffected by variations or absence of solar irradiation. • System is suitable for rural as well as other areas having open well or other water sources. • Mathematical modelling and simulation using real solar irradiation for performance evaluation. Abstract A novel off-grid small power generation system using locally available sources is proposed in this paper for the areas, where the open-wells or the permanent sources of water are available. Although, the system can be installed anywhere, but its installation in remote and rural areas, where there is no access of electricity, can be an interesting application. The proposed system comprises of a solar photovoltaic (SPV) system, solar water pump, pico-hydro turbine-generator and pumped-hydro energy storage system. Its operation is quite different from all other existing SPV power generating systems. In this paper, an innovative power generation technique is developed, due to which the output power of the proposed system is absolutely unaffected by the changes that occur in solar irradiation. The proposed system does not require the use of batteries, inverter, transformer, and charging or controlling circuits at all. The attractive features of the system are simplicity, reliability and ability to generate continuous power at constant voltage irrespective of variations or absence of solar irradiation. The mathematical model of the proposed system has been developed in the paper. The simulation is carried out using real solar irradiation for performance evaluation of the proposed model. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The solar action to biomass was proposed for "breaking" the biomass to fuels. • The breaking temperature was greatly lowered via solar thermolysis plus electrolysis. • The solar chemical process achieved a high solar utilization and biomass conversion. • The mechanism can be revealed by the thermo/electro-induced free radical reactions. • The process features a renewable and sustainable system of solar and biomass to fuel. Abstract In this paper, secondary solar action to biomass, focused on the conceptualized intersection of solar energy and biomass, is presented to illustrate how "breaking" of biomass to biofuels plus hydrogen can be utilized for the adaptation of Solar Thermal Electrochemical Process (STEP) chemistry. This Solar Thermal Electrochemical Process (STEP) system was designed and employed for the synergetic solar energy and corresponding chemistry to provide an action of biomass for efficient solar and biomass utilization - production of biofuels plus hydrogen. The control and modulation of solar fields and sub-chemical reactions were adopted to achieve a high utilization of solar energy, high chemical conversion rate, and high selectivity of the biomass to achieve rich biofuels and abundant hydrogen. The Solar Thermal Electrochemical Process (STEP) temperature of the breakdown reaction was greatly lowered by using electrolysis, as compared with the conventional pyrolysis. Based on their structural complexity and thermal stability, cellulose and lignin are well-suited for the production of biofuel and hydrogen. Through the coupling of thermolysis and electrolysis, the Solar Thermal Electrochemical Process (STEP) hydrogen production from cellulose was 7.2 times higher under a current of 100 mA and 8.8 times higher at 400 mA compared with pyrolysis at 200 °C. The Solar Thermal Electrochemical Process (STEP) lignin conversions were significantly improved by reaching 87.22%, 21.78%, 57.72%, and 7.22% (340 °C, 400 mA), while the pyrolysis achieved only 52.39%, 19.48%, 25.81%, and 7.10% (340 °C, 0 mA), respectively, for the total rate, solid, liquid, and gas fractions. With electrochemical synergy to help, the Solar Thermal Electrochemical Process (STEP) process efficiently and selectively produced gas hydrocarbons, liquid biofuel, and hydrogen. The light hydrocarbons in the gas phase, such as methane, ethane, and n-pentane, became more abundant via thermo-electrolysis. The Solar Thermal Electrochemical Process (STEP) chemistry for converting biomass to biofuels and hydrogen was also elucidated in this paper. The simplified mechanism can best be described by a series of thermo/electro-induced free radical reactions. The system, built on solar energy and specific chemical reactions, features a perfect, green, sustainable, and recyclable operation to transform solar biomass to biofuels and hydrogen. [ABSTRACT FROM AUTHOR]

• A medium–high temperature solar-integrated energy system is proposed. • CO 2 is used for the thermal conductivity medium in the solar collector. • Electroanalysis system is introduced to treat concentrated brine. • 4E analysis are adopted to evaluate the system's performance. • The system's annual income is 27645$, with a simple payback period of 8.62 years. This paper proposes a solar-integrated energy system at medium–high temperature (i.e., working temperature >300 °C) for power generation, desalination, and sodium hydroxide (NaOH) production. The system consists of four subsystems, including parabolic trough collector (PTC), organic Rankine cycle (ORC), multi-effect distillation (MED), and electrodialysis. The PTC system uses CO 2 gas as the working medium to obtain medium–high temperature heat sources. The electrodialysis system electrolyzes the brine to obtain NaOH and HCl , thus avoiding environmental pollution. Energy, exergy, economic and environmental analysis were adopted to evaluate the system's performance, and six critical parameters were investigated. The results showed that the system production of desalinated water, NaOH, and HCl was 106.75 kg/h, 10.61 kg/h, and 48.46 kg/h, respectively, when the direct normal irradiance was 500 W/m2. The net output power of the ORC and the power consumption of the electroanalysis system reached 23.07 kW and 5.00 kW, respectively. The power consumption of the PTC compressor was 8.01 kW. The exergy destruction of solar collector accounted for the most significant proportion, reaching 76.98%. The exergy efficiency of the system reached 12.42%. Among the six different ORC working mediums (R134a, R152a, R600, R600a, R717, and Pentane), Pentane performed the best in the integrated system, while R134a performed the worst. The annual income of the system could reach 27,645 $, with a simple payback period and payback period of 8.62 years and 10.12 years, respectively. The net present value could reach 1,103,722 $. The system could reduce CO 2 emissions by 5.64 tons per year. The research in this paper contributes to understanding the overall characteristics of solar-integrated energy systems when using gaseous working mediums to achieve medium and high-temperature thermal storage. It provides a reference for the development of more efficient solar-integrated energy systems. [ABSTRACT FROM AUTHOR]

• An optimization analysis was performed between water flux and Gain output ratio. • Study of effect of operating and geometric parameters on performance of the system. • Solar thermal energy is utilized to power a desalination process. • Polyethylene membrane exhibit the highest permeate water flux. • Polytetrafluoroethylene membrane provides the maximum Gain output ratio. In this paper, a mathematical model was developed, and numerical simulations were conducted to analyze the direct contact membrane distillation process (DCMD) utilizing solar energy. The objective is to identify the optimal operating point, flow parameters, dimensions, and membrane properties of membrane module in terms of permeate water flux and GOR. The novel aspect of this paper is to analyze the flow patterns in the feed and permeate regions on performance of DCMD to maximize water production by optimizing the balance between permeate water flux and GOR. Additionally, the study will identify the most suitable location for installing the MD system based on factors such as solar energy availability and average annual temperature. The results show that the polyethylene (PE) membrane provides the highest permeate water flux, while the polytetrafluoroethylene (PTFE) membrane provides the highest GOR. A significant increase in permeate water flux and GOR is observed when the flow changes from laminar to turbulent. The study also examines the effect of membrane module dimensions, where increasing the length decreases flux but increases GOR, while increasing the width increases flux but decreases GOR. The study also reveals that countries with high annual average temperatures produce higher permeate water flux and GOR. The paper also delves into the effect of membrane properties on water flux and GOR. It is observed that a membrane with high porosity, low thickness, and having a pore size greater than 0.14 µm is desirable. [ABSTRACT FROM AUTHOR]

• A continuous 24-hour power generation method enabled by solar photovoltaic/thermal conversion and sky radiative cooling; • The design, optimization and manufacture of PV-TEG-PCM hybrid system; • A full-day experimental test and numerical analysis on the electrical, thermal and radiative cooling performance of system; • PV electrical efficiency up to 19.6, TEG voltage up to 0.29 V during diurnal hours and 0.15 V at nocturnal hours. A novel concept of energy harvesting method for continuous 24-hour power generation enabled by solar diurnal photovoltaic/thermal conversion and nocturnal sky radiative cooling by conventional photovoltaic (PV) combined with thermoelectric generator (TEG) and phase change material (PV-TEG-PCM system). The system generated photovoltaic power during diurnal hours, and TEG utilized temperature difference between PV and PCM to achieve full-day power generation. PCM avoided PV overheating during diurnal hours and increased the temperature difference during nocturnal hours. In this paper, the PV-TEG-PCM system was designed, optimized, and manufactured. Firstly, full-day electrical, thermal and radiative cooling experiments on four commercial PV cell were tested. The crystalline silicon solar cell exhibited high solar absorption performance in PV conversion band of 0.3–1.1 μm and strong thermal emission/absorption performance within thermal radiation band of 4–25 μm. In addition, the electrical, thermal and radiative cooling experiments were done under constant light and cold side. The thermoelectrical model was established and verified. By structure optimization, the system achieved peak efficiency and power generation at phase-transition temperature of 38 °C and layer thickness of 30 mm. Thirdly, the full-day electrical, thermal and radiative cooling performance of PV-TEG-PCM system was tested outdoors. The electrical efficiency of PV reached up to 19.6 %, and total maximum electrical efficiency of TEG throughout the day reached 1.2 %, with overall system efficiency reaching up to 20.8 %. The voltage of TEG reached up to 0.29 V during diurnal hours and up to 0.15 V at nocturnal hours, which was used for solar streetlighting and urban building power supply-lighting composite energy system. [ABSTRACT FROM AUTHOR]

• A new integrated system of solar-assisted jet enthalpy pump is proposed. • The performances of the new system and the traditional system are compared. • The new integrated system enhances the jet effect and low-temperature adaptability. • The new integrated approach improves heat output by 45.8% and COP by 22.5% • The new system is superior to the traditional systems within the scope of the study. Solar energy and air source heat pumps are common heat sources for clean heating, but at lower ambient temperatures, the performance of solar energy and air source heat pumps will decline significantly, which can be ameliorated by integrating the two heat sources. However, the range of solar radiation and ambient temperature variation is very wide, and the existing integration methods cannot guarantee that they are optimal over a wide range. Therefore, this paper proposes a novel integration method of solar energy and jet enthalpy air source heat pump suitable for cold regions, where solar energy is used to heat the refrigerant in the jet branch to increase the flow rate of the jet branch, which enhances the effect of jet enthalpy. Under varying outdoor temperatures and solar radiations, the performances of the new integrated system and the traditional integrated systems are compared by simulation method. The results show that within the scope of this study (outdoor temperatures ranging from −30 °C to 10 °C, and radiations from 200 to 800 W/m2), the heat output and coefficient of performance of the new system are higher than those of the existing integrated systems. At an outdoor temperature of −30 °C and a radiation of 500 W/m2, the new system increases heat output by 45.8 % and coefficient of performance by 22.5 % compared with the existing two systems. This research can promote the application of solar energy and air source heat pump heating in cold regions. [ABSTRACT FROM AUTHOR]

This paper proposes a new strategy for implementing the Reconfigurable Solar Photovoltaic array or Dynamic Photovoltaic array under repeating shade conditions. The repeating shades are mainly caused by the civil structures, buildings, poles, etc., present in the vicinity of a Dynamic Photovoltaic array. This paper presents a new algorithm to minimize the processing time in case of repeating shades. According to which, the controller does not have to perform the exhaustive calculations at each shade condition. Instead, the algorithm compares the present shade response with the previous shade responses. Simulation of 4-by-4 size Dynamic Photovoltaic array has been carried out. Experimental tests of a Dynamic Photovoltaic array under resistive load conditions have been conducted. A switch-network of double pole double throw switches has been proposed and is used in the Dynamic Photovoltaic array experimental test. Switch-count of the proposed switch-network is one-third and significantly less compared to the conventional semiconductor switch-network. [ABSTRACT FROM AUTHOR]

The small-scale compressed air energy storage system (CAES) combined with renewable energy sources (RES) is becoming increasing popular in distributed energy system (DES), which allows RES uninterrupted and improves the supply capacity of power system. In order to balance the electricity load and improve the energy efficiency of CCHP system in combined cooling, heating and power (CCHP) system, the paper described a CCHP system combined with solar and compressed air energy storage (CCHP-S-CAES). Solar energy was coupled with the CAES in this paper to heat the high-pressure air from air storage cavern. The proposed system consists of a conventional CCHP, a CAES and a solar energy collector/storage system, which stores the surplus electric power of gas turbine during off-peak time and releases it during on-peak time. Sensitivity analysis on the CCHP-S-CAES system was conducted to investigate the effects of the key parameters on its performances. It is clear that the performances of the CCHP-S-CAES system are mainly determined by the pressure ratio of compressor, the inlet pressure and temperature of turbine and the effectiveness of heat exchangers. In addition, a multi-objective optimization based on the Non-dominated sorting Genetic Algorithm-II (NSGA-II) is performed for obtaining the optimum performance of the CCHP-S-CAES system from the view of investment cost and exergy efficiency. The results show that the optimal exergy efficiency of the proposed system is about 53.10% and 45.36% in maximum heating condition and maximum cooling condition respectively. [ABSTRACT FROM AUTHOR]

Solar photovoltaic plants are widely integrated into most countries worldwide. Due to the ever-growing utilization of solar photovoltaic plants, either via grid-connection or stand-alone networks, dramatic changes can be anticipated in both power system planning and operating stages. Solar photovoltaic integration requires the capability of handling the uncertainty and fluctuations of power output. In this case, solar photovoltaic power forecasting is a crucial aspect to ensure optimum planning and modelling of the solar photovoltaic plants. Accurate forecasting provides the grid operators and power system designers with significant information to design an optimal solar photovoltaic plant as well as managing the power of demand and supply. This paper presents an extensive review on recent advancements in the field of solar photovoltaic power forecasting. This paper aims to analyze and compare various methods of solar photovoltaic power forecasting in terms of characteristics and performance. This work classifies solar photovoltaic power forecasting methods into three major categories i.e., time-series statistical methods, physical methods, and ensemble methods. To date, Artificial Intelligence approaches are widely used due to their capability in solving the non-linear and complex structure of data. The performance analysis shows that these methods outperform the traditional methods. Recently, the ensemble methods were also developed by researchers to extract the unique features of single models to enhance the forecast model performances. This combination produces accurate results compared to individual models. This paper also elaborates on the metrics assessment which was implemented to evaluate the forecast model performances. This work provides information which is beneficial for researchers and engineers who are involved in the modelling and planning of the solar photovoltaic plant. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mathematical modeling of membrane distillation considering concentration polarization. • Integration of membrane distillation into a liquid desiccant air conditioning system. • The hybrid system driven by solar energy with a batch-wise operation. • Feasibility analysis of the hybrid system in a hot and humid climate area. • System performance evaluation in terms of air dehumidification and water production. Membrane distillation (MD) is a promising method for liquid desiccant (LD) regeneration as it can mitigate LD carryover and produce freshwater as a by-product. Previous research on MD regeneration was mainly focused on performance evaluation and optimization of the regenerator itself. This paper proposed a hybrid solar-driven direct contact MD (DCMD) regeneration-assisted liquid desiccant air conditioning (LDAC) system for air dehumidification, cooling, and freshwater production. A mathematical model for the DCMD regenerator was first developed by considering both temperature and concentration polarizations. This model was validated against the experimental data in terms of the outlet channel temperature and LD solution concentration in the feed tank with relative deviations of ± 9.8 % and ± 0.5 %, respectively. The DCMD model was further integrated into an LDAC system with a batch-wise operation. To investigate the technical feasibility of the proposed system, a one-week simulation was conducted in a residential house during summer in a tropical climate area of Australia. The results showed that the latent heat load was effectively removed from the process air and the regenerated liquid desiccant solution can meet the dehumidification requirement with a concentration over 30.0 wt%. The dehumidification rate and regeneration rate were at 0.49–1.25 kg/h and 0.95–4.25 kg/h, respectively. Solar energy contributed to 52 %-78 % of the total system thermal energy consumption. Furthermore, this system can produce 11.0–12.8 kg of water daily. [ABSTRACT FROM AUTHOR]

• A novel model of solar thermal power system is conceptualized. • Power density of 44.33 W m−2 and efficiency of 4.43 % are reported under AM 1.5. • Influential laws of key design parameters and operation conditions are revealed. • A maximum of 9.38 % is achieved by optimizing the thermal conductivity. • The most and least sensitive factors are identified by local sensitivity analyses. While solar energy offers a promising solution for sustainable energy, there's a continuous drive to explore alternative methods of solar power generation. This paper introduces a novel solar power generation hybrid system that merges an angle-independent evacuated U-tube solar collector (EUSC) with a thermally regenerating thermocapacitive cycle (TRTC). Under AM 1.5 conditions, the hybrid system is anticipated to achieve a power density of 44.33 W m−2, accompanied by an efficiency of 4.43 %, underscoring its great prospect for practical applications. To unlock the performance potential, considerable parametric studies are conducted to find out diverse strategies to boost the hybrid system's efficacy, encompassing the elevation of EUSC's inlet temperature, reduction of external environmental temperature, moderation of fluid velocity within EUSC, and enhancement of thermal conductivity in the TRTC. Through meticulous optimization of thermal conductivity between TRTC and the environment, the hybrid system's theoretical efficiency can attain a maximum of 9.38 %. A gradient-based local sensitivity analysis pinpoints that the EUSC's internal fluid flow velocity is the most sensitive while the thermal conductivity coefficient between the TRTC and EUSC is the least sensitive. These results uncover key information critical for efficiently designing and operating the hybrid system. [ABSTRACT FROM AUTHOR]

Operational flow chart strategy of solar monofacial (mPV) and bifacial (bPV) on-grid renewable energy systems. [Display omitted] • Optimal energy management of an on-grid mPV and bPV systems are investigated. • Realistic measured data are obtained from formal institutions. • Marine Predators Optimization algorithm minimizes Loss of Power Supply Probability. • The bPV is more reliable, feasible and more ecological than the mPV solar systems. • The bifacial PV technology is recommended for future PV installations. This paper introduces an optimal energy management and a comprehensive innovative comparison between on-grid monofacial and bifacial solar photovoltaic systems in terms of energy production, reliability, economic feasibility, ecological impact, footprint area, and other performance indicators. This is to satisfy the load demand of Al-Husainya city, Jordan. Realistic measured data are obtained from authoritative companies in Jordan. This includes ambient temperature, solar irradiance, and a utility-scale load demand. The optimal sizing and energy management strategy are achieved using Marine Predators optimization algorithm. This is done by minimizing Loss of Power Supply Probability. The decision variable is the number of photovoltaic modules. The unit investigation shows that the maximum power of the bifacial panel is increased compared with a monofacial module. So, this will highly affect system size and hence reliability, footprint required area, cost and ecological indicators are impacted too. Results show that the minimized values of the objective function of Loss of Power Supply Probability for monofacial and bifacial systems are 0.3534 % and 0.2511 %, respectively. The number of monofacial and bifacial panels are 12,940 and 11,584 respectively. In addition, the area required to install the bifacial array is decreased by 10.4791 % compared with the monofacial array. Finally, four additional optimization algorithms were used to validate and compare with the obtained results using the Marine Predators algorithm. The methodology described in this paper, which adopts the bifacial photovoltaic technology, is recommended and it can be applied anywhere to get highly reliable, feasible, and more environmentally friendly solar energy systems. [ABSTRACT FROM AUTHOR]

• A comparison method between energy-only and energy and reserve model. • Higher revenue for flexible technologies was achieved for joint model. • The down reserve proved to be more required in high RES systems. • The study showed significant difference in operation between two models. The requirements for ancillary services in energy systems are growing as the amount of renewable energy sources such as solar and wind increases. On the other hand, the system can benefit from extra sources of flexibility thanks to the increased digitalization that enables successful integration of demand response and energy storage. The majority of recent energy system analysis research did not consider the regulation markets. As a result, these investigations preclude the ability to fully evaluate the advantages of energy storage and flexible cooling loads. With the method outlined in this paper, it is possible to compare the two strategies and assess the advantages of energy storage and flexible cooling loads for each strategy. In addition to the energy storage systems, the case study in this paper focuses on flexible cooling loads as a significant consumer in the system. According to the findings, the system's operating costs increased by 19.4% when reserve limitations were placed. Furthermore, the findings demonstrated that when flexible assets were permitted to participate in the reserve market, they generated significantly higher incomes. According to the findings, mechanisms that will allow energy storage and demand response to provide reserve capacities as well as the growth of reserve markets are both necessary. [ABSTRACT FROM AUTHOR]

In this paper, an alternative renewable energy concept, i.e. concept of solar power plant with short diffuser (SPD) was investigated through the development of a numerical model with simplifications due to general complexity. The mentioned alternative energy concept is based on the possibility of utilizing an artificially created and maintained convective vortex system in the surrounding atmosphere. Finally, it is assumed that the specific vortex system would able to deliver useful mechanical work which then can be used to produce carbon-free electricity via turbine assembly. Preliminary numerical results were presented as a case study for SPD plants using a solar collector diameter of 600 m with a diffuser of 30 m in maximal and 25 in minimal diameter. According to the obtained numerical simulations, for the considered case, it was found that pressure potential should be below 5 kPa in general (with mass air flow rates less than 31 t/s) in order to enable reasonable operating conditions for commercial wind turbine technologies (a specific pressure potential range was defined in order to provide reasonable parameters related to the vortex system). Namely, for pressure potentials ranging between 3.5 kPa to 5.0 kPa, and mass air flow rates from 26 to 31 t/s, the plant would be able to deliver between 5.17 MW to 16.95 MW of nominal electric power output with an associated range of wind turbine operating air velocities from 30 m/s to 50 m/s. A comparison of the numerical results was obtained by using available observation data and reasonable matching was achieved, i.e. partial validation of the developed numerical model due to the non-existence of an experimental plant. Current research related to SPD concept development is still in the stage of numerically based experiments, which are crucial and important towards the consideration of a prototype plant. Therefore, the gained and presented findings in this paper are certainly valuable for the further development of the herein analyzed alternative renewable energy concept and provide a base for the final experimental realization of a prototype plant. [ABSTRACT FROM AUTHOR]

The use of zeotropic fluid mixtures in refrigeration cycles and heat pumps has been widely studied in the last three decades or so. However it is only in the past few years that the use of zeotropic mixtures in power generation applications has been analysed in a large number of studies, mostly with low grade heat as the energy source. This paper presents a review of the recent research on power cycles with zeotropic mixtures as the working fluid. The available literature primarily discusses the thermodynamic performance of the mixture power cycles through energy and exergy analyses but there are some studies which also consider the economic aspects through the investigation of capital investment costs or through a thermoeconomic analysis. The reviewed literature in this paper is divided based on the various applications such as solar energy based power systems, geothermal heat based power systems, waste heat recovery power systems, or generic studies. The fluid mixtures used in the various studies are listed along with the key operation parameters and the scale of the power plant. In order to limit the scope of the review, only the studies with system level analysis of various power cycles are considered. An overview of the key trends and general conclusions from the various studies and some possible directions for future research are also presented. [ABSTRACT FROM AUTHOR]

This paper presents thermodynamic modelling and simulation study of a small scale saturated solar organic Rankine cycle (ORC) which consists of a stationary, flat plate solar energy collector that is utilised as a vapour generator, a vane expander, a water-cooled condenser and a pump. Simulations are conducted under constant condensing temperature/pressure and various cycle pressure ratios (PR) for 24 organic thermofluids including Hydrocarbons (HCs), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), Hydrofluoroethers (HFEs) and Hydrofluoroolefins (HFOs). Special attention is given to the influence of PR and fluids’ physical properties on the solar ORC performance as well as fluids’ environmental and safety impacts including global warming potential (GWP), flammability and toxicity. The simulation results indicate that when the same fluid is considered, pressure ratio of the cycle leads to various operating conditions such as collector (evaporating) pressure which results in various collector, expander and cycle efficiency. For instance, increasing the pressure ratio of the cycle enhances the net work output and the thermal efficiency of the cycle, whereas it decreases the flat plate collector efficiency. The results also indicate that the proposed system produces the maximum net work output of 210.45 W with a thermal efficiency of 9.64% by using 1-butene. Furthermore, trans -2-butene, cis -2-butene, R600, R600a, R601, R601a and neopentane (HC), R227ea and R236fa (HFC), RC318 (PFC) and R1234ze (HFO) show promising solar ORC thermal performances. However, the flammability problem of HCs and global warming potential issue of HFCs and PFCs limit their applications, owing to the safety and environmental concerns. On the other hand, in terms of the environmental impact, thermofluids such as RE347mcc, RE245fa2 (HFEs) and R1234ze, R1233zd (HFOs) offer an attractive alternative, yet they were neither the most efficient, nor generated the highest amount of net work output. This paper provides thermofluids’ selection guidelines to achieve maximum efficiency within solar thermal energy technologies while keeping environmental impacts into considerations. [ABSTRACT FROM AUTHOR]

The solar array layout is one of the critical factors affecting the output performance of a solar array on a stratospheric airship. Optimizing the layout to improve output energy per day is very important for a long endurance vehicle, but the research about this subject is rare. This paper outlines a numerical method based on a rotating model of a stratospheric airship to optimize the solar array layout. Combined with the solar radiation model, the solar array layout optimization model applying genetic algorithm is developed using a MATLAB computer program in this paper. Compared with the design parameters of three stratospheric solar-powered airships, the theoretical model is proved to be feasible. In the course of the study, the effects of the starting point and the central angle of solar array are discussed in detail. In addition, the optimal results of the solar array layout for four common situations are investigated using the method. The results indicate that this method is helpful in the preparation stage for installing large area flexible solar arrays. [ABSTRACT FROM AUTHOR]

Significant penetration of renewable generations (RGs) and mass roll-out of plug-in electric vehicles (PEVs) will pay a vital role in delivering the low carbon energy future and low emissions of greenhouse gas (GHG) that are responsible for the global climate change. However, it is of considerable difficulties to precisely forecast the undispatchable and intermittent wind and solar power generations. The uncoordinated charging of PEVs imposes further challenges on the unit commitment in modern grid operations. In this paper, all these factors are comprehensively investigated for the first time within a novel hybrid unit commitment framework, namely UCsRP, which considers a wide range of scenarios in renewable generations and demand side management of dispatchable PEVs load. UCsRP is however an extremely challenging optimisation problem not only due to the large scale, mixed integer and nonlinearity, but also due to the double uncertainties relating to the renewable generations and PEV charging and discharging. In this paper, a meta-heuristic solving tool is introduced for solving the UCsRP problem. A key to improve the reliability of the unit commitment is to generate a range of scenarios based on multiple distributions of renewable generations under different prediction errors and extreme predicted value conditions. This is achieved by introducing a novel multi-zone sampling method. A comprehensive study considering four different cases of unit commitment problems with various weather and season scenarios using real power system data are conducted and solved, and smart management of charging and discharging of PEVs are incorporated into the problem. Test results confirm the efficacy of the proposed framework and new solving tool for UCsRP problem. The economic effects of various scenarios are comprehensively evaluated and compared based on the average economic cost index, and several important findings are revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new method for EROI calculation by stocks/flows-funds/services. • Case study " green hydrogen " by water electrolysis EROI = 0.97. • Energy sustainability for Energy Carrier production technologies. • Strong sustainability vs. weak sustainability the N.G. Roegen approach. • Energy embedded evaluation in Net Energy Analysis procedure. Nowadays there is a considerable interest in studying the direct and indirect energies involved in products and services. This is particularly critical when novel energy resources are exploited by complex technological chains and to determine if they can indeed guarantee an useful energy societal supply. Unfortunately, there is no universally accepted procedure for doing this. The present paper aims to suggest a new procedure to evaluate the EROI of technologies producing energy carriers based on the stocks/flows-funds/services production model of N.G. Roegen. The suggested method can uniquely identify the energy flows involved in the technology consistent with biophysical and anthropological boundaries. This analytical formulation can be used either for single technologies or combination of them in series or parallel using different energy resources. Specific recommendations in the use of the Cumulative Energy Demand and Global Energy Requirements in the Net Energy Analysis, as well as in the evaluation of both for an electrical system are reported. The approach is here applied to the analysis of electrolytic H 2 production using electricity produced by a photovoltaic panel ("green hydrogen"). The resulting EROI = 0.97 means that the technology is not sustainable, requiring 3% energy from the anthropological sphere to support it. The paper is organized as follows: providing a narrative model for EROI evaluation consistent with anthropological and biophysical spheres; covering the definition of stocks/flows - funds/services model for EROI evaluation; analysing and suggesting uses of the model for energy technologies scoring and selection based on sustainability and presenting a numerical case study. [ABSTRACT FROM AUTHOR]

The installation of photovoltaic power plants in 2015 compared to 2014 registered a growth of 25.6%, reaching a cumulative power equal to 229 GW. In developed solar markets, as many European countries, the sector is pushed by the alignment between the electric power demanded and the one offered. Consequently, self-consumption makes consumers active players of the energy transition. Italy is evaluated as a case study in this paper, in fact is the first country in the world where solar energy contributes largely to the national energetic demand. This paper aims to evaluate photovoltaic systems in residential sector without subsidies. Economic and environmental results are proposed and the indicators used are Net Present Value, Discounted Payback Time and Reduction in the Emissions of Carbon Dioxide. Three sizes (3 kW, 6 kW and 20 kW) are evaluated. In addition, a sensitivity analysis of critical variables (investment cost, annual electricity purchase price, annual electricity sales price, opportunity cost, tax deduction unitary, period of fiscal deduction, average annual insolation and percentage of energy self-consumption) demonstrates the robustness of the economic results. Also for environmental evaluation, alternative scenarios are proposed varying the value of emissions released by source energy analysed (photovoltaic, coal, oil and gas). Economic and environmental results suggest that small-scale photovoltaic systems can support the transition towards a sustainable energy mix. [ABSTRACT FROM AUTHOR]

[Display omitted] • Theoretical and run-test evaluation of the 50 MW beam-down power plant is conducted. • The variation in heliostat efficiency, flux density, and power generation is analyzed. • The average outlet temperature of the molten salt was up to 559℃ for 50 min. • The flux density of hyperboloid mirror on four typical days is 10.2/11.2/10.9/9 kW/m2. • The flux density of receiver on four typical days is 353.6/399.1/381.7/314.2 kW/m2. The beam-down concentrating solar power plant has the advantages of high concentrating ratio, low installation and maintenance requirements, and low pump consumption. To conduct further theoretical and run-test evaluations of the optical and thermal performance of the beam-down concentrating solar power system, the Yumen Xinneng 50 MW beam-down power plant is analyzed in this research. The variation of the heliostat field efficiency, hyperboloid mirror flux density, receiver flux density, and annual power generation under various operating parameters is discussed. The run-test results from June 12th indicated an average outlet temperature of molten salt reached 559°C between 13:07 and 13:56 under an average direct normal irradiation of 739.7 W/m2. The corresponding inlet temperature increased from 302.3°C to 307.6°C due to the rewarming effect caused by the increase in hot molten salt. Regarding the simulation results, the recommended design parameters for the vertex ratio of the hyperboloid mirror are between 0.775 and 0.8 to mitigate the contradiction between initial investment and optical efficiency. The maximum values of cosine efficiency, shading and blocking efficiency, shading efficiency of the hyperboloid mirror, and attenuation efficiency for the heliostat field are 85.56%, 99.96%, 99.35%, and 97.46% on June 1st for the maximum solar elevation angle of 70.72°. Consequently, the maximum values of the average hyperboloid mirror flux density and receiver flux density are 11.2 kW/m2 and 399.1 kW/m2 on June 1st. The maximum power generation for a 7-day period is 4674.22 MWe in June with a duration time of 100 hours. This paper can further expand research on the comprehensive performance of beam-down power plants. [ABSTRACT FROM AUTHOR]

The solar and wind power generation is stochastic in nature. Consequently, it is difficult to obtain steady power output from these renewable sources. Storage element (mainly battery) used in typical solar/wind hybrid system has also its inherent shortcomings. However, power generation from renewable energy sources like solar and wind is having paramount significance in the context of impending fossil fuel shortage, environmental degradation, remote electricity supply, etc. Hence, an alternate mechanism for hybridization of solar and wind resources to obtain a steady power output could undoubtedly be a great accomplishment in prevailing energy scenario across the world. The present paper analyses the performance of such an eccentric solar–wind hybridized model with spring storage system which is capable of delivering steady power yield despite intermittency of the sources. The likely annual performance of this unusual solar–wind hybridized model is evaluated under a sub-tropical climatic condition in north-east India in terms of various characteristics and effective performance indicators such as energy generation characteristics, effect of storage capacity, efficiency of the generating system, capacity factor of the plant, energy to load ratio, normalized power yield, and plant utilization factor. The considered system in the paper has been designed and simulated in LabVIEW graphical programming environment. It has been found for the given climatic condition that maximum wind energy and solar energy fraction of the plant reaches up to 84% and 16% respectively with annual average efficiency of 24.21% for wind turbine unit and 65.52% for solar thermal unit. To make evident the success of the system, a performative comparison has been drawn with obtained results in the proposed scheme and the testified results in existent solar–wind renewable energy system. The analysis in the study substantiates that performance of the proposed hybridized model is considerably superior to that of conventional and established solar–wind based hybrid technologies. [ABSTRACT FROM AUTHOR]

The negative environmental impacts of burning fossil fuels have forced the energy research community seriously to consider renewable sources, such as naturally available solar energy. Thermally powered refrigeration technologies are classified into two categories: thermo-mechanical technology and sorption technology (open systems or closed systems). This paper provides a detailed review of the solar closed sorption (absorption and adsorption) refrigeration systems, which utilise working pairs (fluids). After an introduction of the basic principles of these systems, the history of development and recent advances in solar sorption refrigeration technologies are reported. The adsorption cooling typically has a lower heat source temperature requirement than the absorption cooling. Based on the coefficient of performance (COP), the absorption systems are preferred over the adsorption systems, and the higher temperature issues can be easily handled with solar adsorption systems. The thermodynamic properties of most common working fluids, as well as the use of ternary mixtures in solar-powered absorption systems, have been reviewed in this study. The paper also refers to new approaches to increase the efficiency and sustainability of the basic adsorption cycles, such as the development of hybrid or thermal energy storage adsorption systems. This research shows that solar-powered closed sorption refrigeration technologies can be attractive alternatives not only to serve the needs for air-conditioning, refrigeration, ice making, thermal energy storage or hybrid heating and cooling purposes but also to meet the demands for energy conservation and environmental protection. [ABSTRACT FROM AUTHOR]

In this paper, a new experimental approach is proposed to enhance the performances of the conventional solar still using the natural circulation effect inside the still. The idea consists in generating air flow by a rectangular natural circulation loop appended to the rear side of the still. The proposed still was tested during summer period and the experimental data presented in this paper concerns four typical days. The convective heat transfer coefficient is evaluated and compared with Dunkle’s model. The comparison shows that convective heat transfer is considerably improved by the air convection created inside the still. The natural circulation phenomenon in the still is studied and a good agreement between the experimental data and Vijajan’s laminar correlation is found. Therefore, natural circulation phenomenon is found to have a good effect on the still performances where the still daily productivity is of 3.72 kg/m 2 and the maximum efficiency is of 45.15%. [ABSTRACT FROM AUTHOR]

• A CCHP system based on solar energy and thermochemical energy storage is proposed. • Increasing the share of solar energy used in combined cooling, heating and power (CCHP) systems. • The 4E analysis and parameter study of the system are carried out. • The SPECO method is done and provides direction for the optimization of the system. • The effects of the main parameters on the system performance were evaluated. The combination of calcium looping and concentrating solar power (CSP) is a promising energy conversion technology that can greatly increase the share of solar energy used in combined cooling, heating and power (CCHP) systems. This paper designs a CCHP system based on solar energy and thermochemical energy storage. The system runs all day through day and night modes. Under basic working conditions, the energy and exergy efficiencies of the system could reach 56.92 % and 35.94 %, respectively. The system is evaluated by multiple approaches including parametric sensitivity analysis and 4E (energy, exergy, economy and environment)) analyses. The results demonstrate that the system could produce 2618.09 MW of electricity, 305.56 MW of heat and 523.88 MW of cooling capacity per day, respectively. At the same time, the reductions of CO 2 emissions and fossil fuel consumption could reach 2222.76 tons and 696.41 m3 per day, respectively. Furthermore, the increasing mass flow of main turbine inlet could increase both the system efficiency and the exergy efficiency. Thus, it is beneficial to reduce the environmental impact but with the increasing investment cost. In the meanwhile, the exergoeconomic factor and exergoenvironment factor of the system were 55.65 % and 0.139, respectively. Besides, as the extraction flow rate of the intermediate pressure turbine increases, the energy efficiency increases but the exergy efficiency descends. This is unfavorable to reducing the environmental impact, yet it could decrease the investment cost of the system. These results reveal that the hybrid system has the characteristics of high efficiency and emission reduction in energy storage, power generation, heating and cooling, and has great development potential. [ABSTRACT FROM AUTHOR]

• A combined cooling, heating, hydrogen and power multi-generation system is proposed; • Low-grade solar energy in long wavelength is converted to high-grade chemical energy; • Up to 18.8% energy storage ratio and high dispatchability are achieved； • Primary energy saving ratio is 81.78% when compared to the reference system. Solar photovoltaic/thermal (PV/T) hybrid systems are considered energy-efficient and eco-friendly. However, conventional PV/T systems generate electricity with high power fluctuations and low-grade thermal energy. In this paper, dry reforming of methane (DRM) is introduced to convert low-grade thermal energy through chemical reaction and enhance the dispatchability of the PV/T system. A combined cooling, heating, hydrogen and power (CCHHP) multi-generation system that integrates the PV/T, DRM and CCHP (combined cooling, heating and power) is proposed to use the full-spectrum solar energy. Energy and exergy analysis under design and variable working conditions are conducted to analyze the system performance. The results reveal that the proposed system can achieve a high energy conversion efficiency of 61.34 % and 18.8 % energy storage ratio at direct normal irradiance (DNI) of 800 W·m−2. In addition, the system can save up to 81.78 % primary energy when compared with the reference system. This study can facilitate the better design and performance evaluation of PV/T hybrid systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Current approaches in CO 2 conversion and enhancing strategies for solar fuel generation via artificial photosynthesis. • Strategies for improving the photocatalytic activity in solar fuel generations. • Application of biochar-based photocatalysts (BSPs) in CO 2 conversion and H 2 production. • Investigating the Biochar's role in biochar-based photocatalysts. • Challenges and prospects for the future of biochar-based photocatalysts in environmental applications. The imperative of solar-driven methodologies, harnessing the virtually boundless power of sunlight, cannot be overstated in our battle against climate change and the imperative to propel clean fuel production. Photocatalytic innovation, which employs catalysts to initiate eco-friendly chemical reactions, stands out as one of these effective techniques. Biochar, a carbon-rich material derived from organic substances, enhances photocatalytic activity through its porous structure and functional groups. Using biochar as a photocatalyst support reduces electron-hole pair recombination rates, narrows band gaps, improves charge separation, and enhances electron transport. This study explores four main objectives: 1) Current approaches in CO 2 conversion and strategies, including the management perspective of light, the utilization of solar concentrators, and thermal methods for enhancing solar fuel generation via artificial photosynthesis. 2) Critical role of photocatalysis and analyzing the metals and nonmetals doping and the strategic deployment of carbon materials to increase the efficacy in solar fuel generation. 3) Methods and parameters that affect the synthesis of biochar. 4) The role of biochar as a support for improving photocatalytic activity in CO 2 conversion and H 2 production for solar fuel generation. This paper outlines a vision for advancing biochar-based photocatalysts, emphasizing the need to enhance their efficiency and stability. It also highlights the potential for innovative design concepts and the exploration of scalable production techniques. Ultimately, this vision aims to drive progress in solar fuel generation technology for practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bifacial solar modules on rooftops offer up to 22.6% energy yield gains. • Rooftop reflectivity plays a crucial role in maximizing the bifacial potential. • Higher optimal tilt angles for bifacial modules, influenced by rooftop reflectivity. • Parallel intra-module interconnection supports achieving high bifacial yield gains. • Module-level optimizers enhance bifacial energy generation potential by up to 1.4% Bifacial solar modules have emerged as a promising technology in utility-scale photovoltaic systems, experiencing significant growth and capturing a substantial market share worldwide, as reported by the International Technology Roadmap for Photovoltaic (ITRPV) 2023. Despite this progress, the potential of bifacial modules in rooftop applications remains largely unexplored. This paper aims to address this knowledge gap by conducting a comprehensive study utilizing Monte Carlo Ray Tracing techniques coupled with detailed electrical modelling. The primary objective of this study is to investigate the viability of implementing bifacial solar modules on rooftops by examining the potential energy yield gains. By conducting a detailed analysis on a representative rooftop in Canberra, Australia, real-world conditions, and variations are incorporated, providing a more accurate assessment of the energy yield gains achievable in such settings. The simulation results reveal that the implementation of bifacial solar modules on rooftops within Australia can result in energy yield gains of up to 22.6%. These findings demonstrate the considerable potential of bifacial technology in maximizing solar energy production in rooftop applications. The analysis shows significant implications of module and system design on the potential gain. For example, electrical optimisation of individual modules in a system accounted for 1.4% of the bifacial gain. The analysis considers full annual time-step simulation, typical mechanical mounting components, installation orientations and module characteristics, ensuring practical relevance and reliability of the results. [ABSTRACT FROM AUTHOR]

• Novel control method of solar-assisted SMR with no thermal storage. • Designed system produces 148.6 tonne/d of H 2 with heat cogeneration rate of 1.28 MW. • Dried product output is 121 tonne/day, and 931.2 kW of power generation. • The estimated payback period of the proposed system is 9.4 years. • Daily-averaged energy and exergy efficiencies are 65.1% and 46.4%, respectively. This paper proposes a multigeneration plant to produce hydrogen, heat and power, and achieve product drying using the heat recovered from the solar-thermochemical system and a pyrolysis system where biomass and petroleum cokes are utilized to manage those sources for an environmentally benign operation. The developed system is then applied for a case study in the Kingdom of Saudi Arabia and uses three energy sources: biomass, petroleum coke and solar thermal energy. The biomass and petroleum coke blend is first hydro-gasified adiabatically, and then the product gas is steam-reformed in a reactor installed atop a solar tower of a large heliostat field. The steam-methane reactor is maintained hot and producing during nighttime by setting the reaction conditions to autothermal mode. Through the AspenPlus simulations performed, the optimum H 2 /C ratio in an adiabatic hydro-gasifier is found to be 1.5, which maximizes synthetic methane production at about 1300 °C. Most of the exergy destructions takes place in the system components, mainly the compressors with 53%, followed by the reactors with 38%, and heat exchangers with 9% at nighttime operation. The proposed system produces 148.6 tonne/d of H 2 with a heat cogeneration rate of 1.28 MW. Moreover, the dried product output is 121 tonnes/day and 931.2 kW of power generation. The average energy and exergy efficiencies of the present system for over a 24-hour period are obtained to be 65.1% and 46.4%, respectively. [ABSTRACT FROM AUTHOR]

• Introducing a new hybrid cascaded network structure for solar power generation forecasting. • Proposing the MRIG feature selection technique to enhance the forecasting performance. • Implement a deep learning time series prediction model combined of LSTM, NARX, ELM, MRIG methods. • Using the Wavelet Transform module eliminate fluctuation behaviors solar power generation time series. • Validating the performance of the proposed model for short term solar power generation forecasting by a real data sets from Iran. Today, renewable energies have a key role in sustainable and clean power generation. On the other hand, solar energy is available in most regions in developing economies. Therefore, photovoltaic power forecasting is crucial for low-carbon power operation, planning, and trading. In this paper, the proposed hybrid cascaded forecasters network model combines LSTM, NARX, ELM, MRIG feature selection, and WT techniques, enabling accurate Solar Power Generation Forecasting (SPGF) for the next 24 h. By integrating these diverse models, the hybrid approach capitalizes on the strengths of each model and compensates for their weaknesses. This synergy significantly enhances the efficiency and accuracy of the forecasting method, leading to improved SPGF performance. The results of day-ahead SPGF for this case study demonstrate the hybrid model's impressive accuracy. For instance, the average prediction error for SPGF of the Mahan PV power plant resulted in a MAPE of 4.7213%, MAE of 0.0100 MW, and RMSE of 0.0198 MW. [ABSTRACT FROM AUTHOR]

• A novel polygeneration liquid air energy storage system is presented. • An alternative strategy for cold energy utilization is proposed. • Hydrate based processes are integrated to coproduce potable water. • Electrical round-trip and exergy efficiencies of 145.57 % and 72.34 % are achieved. • The advanced system has a high positive net present value of 158.17 million USD. Energy management and freshwater production are recent social concerns due to the population explosion. However, conventional liquid air energy storage (LAES) systems and desalination approaches face low efficiency and high energy consumption challenges. The present paper proposes a novel LAES system coupled with LNG cold energy, solar energy, and hydrate based desalination (HBD) to bridge the research gap at the intersection of electricity and freshwater production. The system develops the respective integration of external cold and heat sources in energy storage and release processes to strengthen the operational characteristics. Additionally, the proposed LAES employs HBD systems in LNG regasification and energy release processes, thus taking advantage of underutilized cold energy. The non-dominated sorting genetic algorithm II is developed to obtain the optimum operating parameters regarding peak shaving and water production. The optimized system is thoroughly analyzed from the energy, exergy, and economic perspectives. The results indicate that the system with 2805.26 tons of daily freshwater production has an electrical round-trip efficiency of 145.57% and an exergy efficiency of 72.34%. A high positive net present value of 158.17 million USD is achieved. Overall, the efficient system, with superior techno-economic performance, provides an extraordinary alternative to enhance the energy management-water nexus in grid dimensions. [ABSTRACT FROM AUTHOR]

• Hybrid system with PEMFC and solar photovoltaic-thermochemical reforming of methanol is proposed. • A novel hydrothermal management method involving methanol and water as coolants is proposed. • The exergy of hybrid system improves by 76.36% compared to the solar thermochemical system. • The efficiency of hybrid system can reach up to 59.15% at the highest efficiency of the PEMFC. The proton exchange membrane fuel cell (PEMFC) is an efficient and clean power unit that has become a research hotspot for scholars around the world, but the hydrothermal management of the PEMFC limits the cell performance and hinders its large-scale application. In the paper, a hybrid system combining solar-assisted reforming of methanol and fuel cell power generation is proposed, in which methanol is used as a coolant in the hydrothermal management of the PEMFC subsystem to take away the waste heat, and further reformed for hydrogen production with the assistance of the solar energy subsystem to improve the hybrid system efficiency. The study is carried out at both the single cell level and system level to investigate the effect of solar energy on the performance of the hybrid system by simulation results, which are obtained from the finite element software, such as the performance of the PEMFC. The results show that the novel hydrothermal management method using methanol and water in the single cell can control the temperature at 60–80 ° C. The highest power density of the single cell reaches 0.595 W/cm2 at a water-to-alcohol ratio of 1:1 and a coolant flow rate of 2.846 mol/s. In addition, the exergy of this hybrid system improves by 76.36% compared to the exergy of the solar thermochemical methanol reforming system at a reaction temperature of 200 ° C when the methanol reforming reaction is more complete. The system efficiency can reach up to 59.15%, compared to the solar thermochemical methanol reforming system and the methanol reforming system heated by combustion of methanol, which can only reach 51.10% and 43.18%, respectively. This study provides a novel method for addressing the hydrothermal management issue of PEMFC and a new idea for the efficient utilization of solar energy. [ABSTRACT FROM AUTHOR]

• A new reactor using concentrated solar power for hydrogen production is proposed. • The thermal performance of the reactor is numerically investigated in detail. • The reactor efficiency can be increased by 2.63–30.21% using the integrated design. • The control strategy is discussed to stabilize the outdoor reactor efficiency. Concentrated solar power and solid oxide electrolysis cells (SOEC) can be combined to produce green hydrogen efficiently. However, heat loss due to fluid transport can be significant. In this paper, a volumetric receiver is first integrated with a tubular SOEC as a whole reactor to reduce the transport heat loss. Numerical investigation shows that the SOEC temperature, in a reference condition, ranges from 760 to 920 °C, which is qualified for regular operation. The efficiency analysis is conducted under different conditions and shows that the reactor efficiency is highly affected by the operating temperature. Therefore, increasing the incident power, decreasing the inlet velocity, or increasing the steam mass fraction would lead to a higher outlet temperature and thus a higher reactor efficiency. Based on the validated model, the integrated design presented in this paper can increase energy conversion efficiency by 2.63–30.21% compared with the separate structure, depending on the operation condition. The last section of this paper discusses the control strategy for the integrated reactor briefly, which aims to stabilize the reactor efficiency in outdoor situations. Compared with the steam mass fraction, the inlet velocity is preferred as a control variable to keep the cathode stable. [ABSTRACT FROM AUTHOR]

• Three new solar aided molten carbonate fuel cell-steam turbine-combined cooling, heating and power (MCFC-ST-CCHP) systems are proposed. • Thermal performances of different MCFC-ST-CCHP systems are studied and compared. • Solar aided MCFC-ST-CCHP systems have obvious advantages than reference system. • Effects of the direct normal irradiance (DNI) of solar energy on the best solar aided MCFC-ST-CCHP system (Scheme 2) are revealed. The efficient use of solar energy and fuel cells has become an important way to achieve the goal of "carbon neutral" power generation. This paper firstly proposes a new molten carbonate fuel cell-steam turbine-combined cooling, heating and power (MCFC-ST-CCHP) system. In order to further improve the performance of the MCFC-ST-CCHP system, three solar aided MCFC-ST-CCHP systems with different solar energy integration modes are proposed in this paper. Solar energy is used to drive the methane dry reforming reaction or replace part of the heating load of high pressure boiler drum or high pressure economizer in heat recovery steam generator. The performances of different systems are studied and compared. The results show that the energy efficiencies, the exergy efficiencies and the specific CO 2 emission rates of three systems are 65.89%, 63.77%, 480.79 g/kWh; 66.25%, 65.12%, 477.93 g/kWh; and 65.86%, 64.88%, 481.08 g/kWh, respectively. The best solar integration mode is to replace part of the heating load of high pressure boiler drum. The impact of solar irradiation intensity on new solar aided MCFC-ST-CCHP system with the best solar integration mode further investigated. The results show that when the direct normal irradiance (DNI) of solar energy changes throughout the day, the new system's solar heat collection efficiency, solar power generation and solar-to-electricity efficiency increase first and then decrease, and the specific CO 2 emission rate of the system decreases first and then increases. [ABSTRACT FROM AUTHOR]

• A novel hydrogen production approach by full spectrum solar energy was proposed. • It combined photothermal synergistic reaction with photovoltaic electrolysis water. • Mathematic model of the approach was developed. • Hydrogen production efficiency of the approach at various conditions was analyzed. • It improved energy conversion efficiency and the efficiency can reach 21.05%. For the development of hydrogen energy, it is very important to find a green and efficient hydrogen production approach. By comparing the existing hydrogen production methods, it can be found that using clean and inexhaustible solar energy to produce hydrogen is very promising. Therefore, for efficient hydrogen production from solar energy, a novel hydrogen production approach using full spectrum solar energy by combining photothermal synergistic reaction with photovoltaic power generation electrolysis water is proposed in the paper. And the relevant hybrid hydrogen production model is also established for calculation and discussion. The simulation results show that the efficiency of the proposed hydrogen production approach can reach 21.05% when the elementary reaction time is 1 ns. However, under the same solar radiation conditions and parameters, if the photothermal synergistic reaction and photovoltaic power generation electrolytic water are simulated separately, the hydrogen production efficiency using only the photothermal synergistic reaction is 7.9% and the hydrogen production efficiency using only photovoltaic power generation electrolytic water is 19.19%. Compared with these two methods, the hydrogen production efficiency of this hybrid hydrogen production approach has been greatly improved. And the hydrogen production efficiency curves of this approach under different conditions (including different separation wavelengths, different photovoltaic panel materials, and different electrolysis temperatures) have been also studied in the paper. Therefore, this study can provide a new train of thought for solar hydrogen production approaches, which may provide guidance for realizing green and efficient hydrogen energy production. [ABSTRACT FROM AUTHOR]

• Advancement in solar thermal technologies and industrial process heating system. • Design and integration of solar heat in the industrial process. • Prospects of solar process heating systems in industries. Energy is the essential need for the development, modernization and economic growth of any nation in the industrial sector. About 32–35% of the total energy of the world is used in the industrial sector. Solar thermal energy application is an initiative towards the sustainable and zero-carbon energy future. Solar thermal collectors are recognized as promising alternatives for fossil fuels in the industrial sector for process heat due to energy security, economic feasibility and environmental benefits. This work is an extensive compilation and review of the recent literature concerning research works carried out to solar thermal collectors and its industrial applications, global advancements in solar thermal technologies, collectors and the solar thermal energy storage system with a focus on the sun tracking system, thermal performance, and modeling techniques. In this review paper, current industrial process-heat systems are classified based on solar collector technologies and heat demand temperatures for the identification of typical applications for solar process heat. These classifications are pertinent to every country within the same industry type along with similar weather and economic conditions. Moreover, future prospects to integrate solar heat in the heat supply level of an industrial company in Pakistan is outlined for a sustainable energy system. It is found that solar thermal technologies can be used for a variety of industrial applications for sustainable energy system in industries and these should be used for industrial applications which are more compatible to be integrated. [ABSTRACT FROM AUTHOR]

• A hybrid system integrating direct steam generation and molten salt is proposed. • The thermodynamic and economic evaluation model are established and validated. • The electricity production of the hybrid system in Tonopah is increased by 14.0%. • Levelized cost of electricity is decreased to 0.116 €/kWh by hybrid system in Tonopah. A novel hybrid parabolic trough power system that integrates direct steam generation and molten salt systems is proposed in this study to stably and efficiently operate solar power plants. The feedwater from the power block is preheated and evaporated in a low temperature direct steam generation solar field. A high-temperature solar field using molten salt as heat transfer fluid is employed to superheat and reheat the steam to 540 °C. The heat transfer model based on energy conversion and balance is applied to numerically investigate the overall performance of various power plants. This paper presents a comparative study of the effects of different locations, steam turbines, and system configurations on the outputs of the power plants. The hybrid systems exhibit favorable system stability and reliability and an excellent overall performance. The molten salt loop percentages of hybrid systems with and without reheat section are only 45.1% and 37.4%, which lead to low energy loss in the operation period and low molten salt freezing protection energy. The annual thermal energy productions of the hybrid systems with and without the reheat section in Tonopah are 685.1 and 691.7 GWh, and the percentages of energy required for freezing protection of those systems are 3.2% and 2.7%, respectively. The hybrid systems with reheat section exhibit optimal electricity production and economic performances compared with those of other configurations. The electricity production increments of novel systems in Tonopah and Lhasa are 14.0% and 14.8%, respectively, compared with those of molten salt systems. [ABSTRACT FROM AUTHOR]

• Design and construction of a new low-cost air-based photovoltaic/thermal collector. • New simulation model for energy and economic performance assessments. • Description of the successful experimental validation of the simulation model. • Case studies for different weather zones by using the heated air in a heat pump. • Energy savings: 52–80%; avoided carbon dioxide: 4.6–10 t/y; pay-back: 3.2–4.8 years. This paper focuses on the design of an innovative low-cost air-based photovoltaic/thermal collector prototype, for which a novel dynamic simulation model is suitably developed in order to investigate its energy performance and economic feasibility under different operating conditions. The main novelty of this photovoltaic/thermal collector is the low-cost heat extraction system, implemented to reduce the photovoltaic cells temperature and to recover thermal energy. The prototype is tested under different operating conditions and the experimental data are used to validate the presented simulation model. The developed tool, implemented in a MatLab code, is used for analysing a suitable case study. The photovoltaic/thermal collectors are coupled to an air-to-air heat pump for space heating of a sample building. A novel performance map of such a coupled system is built with the aim of linking the heat pump coefficient of performance to both the outdoor air temperature and incident solar radiation. In addition, the system energy effectiveness and economic feasibility, compared to those of a traditional system, are assessed for the climate of 8 different European weather zones. Simulation results highlight the effectiveness of the proposed system, estimating primary energy savings (11.0–19.7 MWh/year corresponding to 52–80%), avoided carbon dioxide emissions (4.64–10.4 t CO2 /year), and simple pay-back periods (3.2–4.8 years). [ABSTRACT FROM AUTHOR]

• Hybrid solar photovoltaic-electrical energy storage systems are reviewed for building. • Global status of electrical energy storage for photovoltaic systems is highlighted. • Technical, economic, environmental performances of the hybrid systems are summarized. • Optimization methods and criteria of the hybrid systems are elaborated. Solar energy is globally promoted as an effective alternative power source to fossil fuels because of its easy accessibility and environmental benefit. Solar photovoltaic applications are promising alternative approaches for power supply to buildings, which dominate energy consumption in most urban areas. To compensate for the fluctuating and unpredictable features of solar photovoltaic power generation, electrical energy storage technologies are introduced to align power generation with the building demand. This paper mainly focuses on hybrid photovoltaic-electrical energy storage systems for power generation and supply of buildings and comprehensively summarizes findings of authorized reports and academic research outputs from literatures. The global installation capacity of hybrid photovoltaic-electrical energy storage systems is firstly examined to show the significant progress in emerging markets. Particularly, the latest installation status of photovoltaic-battery energy storage in the leading markets is highlighted as the most popular hybrid photovoltaic-electrical energy storage technology for building applications. The research progress on photovoltaic integrated electrical energy storage technologies is categorized by mechanical, electrochemical and electric storage types, and then analyzed according to the technical, economic and environmental performances. Moreover, extensive research on hybrid photovoltaic-electrical energy storage systems is analyzed and discussed based on the adopted optimization criteria for improving future applications in buildings. It is indicated that the lithium-ion battery, supercapacitor and flywheel storage technologies show promising prospects in storing photovoltaic energy for power supply to buildings. Potential research topics on the performance analysis and optimization evaluation of hybrid photovoltaic-electrical energy storage systems in buildings are identified in aspects of the local adaption, flexible control, grid integration, as well as building resilience and intelligence. This study provides an insight of the current development, research scope and design optimization of hybrid photovoltaic-electrical energy storage systems for power supply to buildings and can serve as an explicit guide for further research in the related area. [ABSTRACT FROM AUTHOR]