Search

[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]

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]

• 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]

• 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 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]

[Display omitted] • A solar energy system with hydrogen energy storage and alkaline fuel cell is proposed. • An optimization model base minimum life cycle cost is developed by Getopt. • The performance of solar energy system without and with electrical storage device are compared. In this paper, a novel solar energy system with hydrogen energy storage and alkaline fuel cell is developed in TRNSYS. The solar energy system without electrical energy storage and solar energy system with battery energy storage are established as the reference systems. The life cycle cost is chosen as the optimal objective, and different operating strategies are developed for the proposed system and the reference systems. The optimal variables and dynamic analysis can be obtained after optimization. Various evaluation criteria, including electricity coverage ratio, annual carbon dioxide emission and levelized cost of energy, are used to comprehensively assess the overall performance of the proposed system and the reference systems. Beijing and Shanghai, which belong to cold region and hot-summer and cold-winter region respectively, are chosen as the study sites for case study. The results show that the proposed system has the lowest life cycle cost, which is 186,484.36 USD and 261,467.43 USD in Shanghai and Beijing, respectively. The proposed system has the highest electricity coverage ratio (which is more than 0.5 for most time of the year), the lowest annual carbon dioxide emission (which is 19,099.34 m3 in Shanghai and 31,525.96 m3 in Beijing) and the lowest levelized cost of energy (which is 0.12 USD/kWh in Shanghai and 0.08 USD/kWh in Beijing). [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]

Highlights • Conducted a theoretical analysis of solar still thermal performance with micro/nano particles. • Evaluated the energy and exergy efficiencies for modified and conventional solar still. • Determined the destructions exergy for different components of solar still. • Estimated the heat transfer coefficients of solar still with and without micro/nano particles. • Estimated the costs of solar still with and without micro/nano particles. Abstract In this paper, a theoretical comparative study between modified solar stills (MSSs) and classical solar still (CSS) was carried out, based on the productivity and the thermal properties. The MSSs contain brackish water mixed with either graphite or copper oxide (CuO) micro/nano particles. Cost estimations of solar still desalination by using micro/nano particles was estimated. exergy destruction in various components of the solar still (SS) were calculated, analyzed and discussed. The exergy loss during the day time comprises the exergy destruction in the main components of the SS like basin plate, brine water, glazier plate and insulation material. The hourly convective, evaporative and radiative heat transfer coefficients (HTCs) with and without micro/nano particles were determined. The exergy destruction in various components of the SS have been analyzed and a solution was suggested. Results revealed that the exergy of evaporation, energy efficiency and exergy efficiency of MSSs were higher than that of the classical one. The daytime energy efficiencies of MSSs with graphite and CuO were 41.18% and 38.61%, respectively, but for the CSS was only 29.17%. The diurnal productivity of the MSSs was increased by 41.18% and 32.35% for graphite and CuO, respectively, compared with CSS. Moreover, the diurnal exergy efficiencies of MSSs were 4.32% and 3.78% for graphite and CuO respectively, while exergy efficiency for CSS was 2.63%. Furthermore, the costs of water production were found to be approximately 0.20, 0.21 and 0.24 RMB/L (1 RMB = 0.15 US $) when using MSS with CuO, MSS with graphite and CSS, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel system is proposed for heating, electricity, fresh water, and ammonia production. • The PCMs are incorporated into the system to avoid performance fluctuations. • The effects of different parameters on the system outputs are investigated. • The solar-driven ammonia production shows a good potential for stabilizing non-dispatchable systems. This research paper designs and analyzes a novel integrated solar-driven system for ammonia synthesis, freshwater production and power generation. The trigeneration system contains a solar thermal subsystem, a thermal energy storage system where the molten salt is used as a heat transfer fluid and storage medium, a solar energy-driven Rankine cycle, a multistage flash distillation, a proton exchange membrane electrolyser array, and an ammonia synthesis unit. The proposed integrated system uses solar energy to charge the molten salt, which flows through a heat exchanger and generates steam for the topping cycle. The exhaust stream of the steam turbine provides heat for the multistage flash distillation (MFD) process. A 20 stage MFD unit is proposed where the seawater is utilized as the feedwater in this study. A portion of the produced freshwater is sent to the PEM electroylzer array for hydrogen production, which is used for ammonia production via the Haber-Bosch process. The thermodynamic analysis of the solar driven multigeneration system is analyzed through the Engineering Equation Solver (EES) and Aspen Plus software packages. The novelty of this study relies on the development of a new solar energy-based integrated system and its application for a selected community with over 10,000 residents to meet all of their needs to be self-sufficient and sustainable. Ammonia (for multiple purposes, such as fuel, energy carrier and feedstock), freshwater and electricity are the useful outputs as targeted in this paper. The study incorporates the phase change materials into the system for thermal energy storage purposes. The performance assessments based on energy and exergy efficiencies are carried out for the overall system and its components. Furthermore, the power, freshwater and ammonia production capacities are studied for better demand coverage. The overall exergy efficiency of the system is determined as 12.1 %, where the ammonia synthesis, power generation, and freshwater production capacities are 0.85 kg/s, 17.6 MW, and 143.97 kg/h respectively. Moreover, the study investigates the energy and exergy efficiencies with and without the presence of an air separation unit. The study results show that the air separation unit has less than 0.3% effect on the overall energy and exergy efficiencies. [ABSTRACT FROM AUTHOR]

• Satisfactory cooling met ratios are achieved with transient supply–demand matching. • A met ratio of 0.95 is obtained with a solar-to-cooling efficiency of 0.24. • The highest energy storage efficiency of the absorption thermal battery is 0.71. • The maximum energy storage density of 157.1 kWh/m3 is achieved. Efficient use of renewable energy, e.g., solar energy, is an important pathway towards net-zero energy buildings and carbon neutrality. However, renewable energy is difficult to be fully utilized due to its instability and intermittency. Thermal energy storage technologies applied in buildings can bridge the gap between renewable energy sources and heating/cooling demands. This study employs a solar absorption thermal battery (SATB) in a building for space cooling. The annual dynamic performance of the SATB is investigated and compared in four representative cities by simulation using an experimentally validated model, considering transient supply–demand matching. Besides, parametric studies are conducted for the SATB designed with different solar collector sizes and solution charges. Results indicate that the SATB achieves satisfactory cooling met ratios (MRs) in different climates when 0.49 m2 solar collector is equipped for each square meter of the serviced room. The highest cooling MR of 0.95 is obtained in Singapore, with an energy storage efficiency (ESE) of 0.66 for the ATB unit, a system ESE (solar-to-cooling) of 0.24, and an energy storage density (ESD) of 125.8 kWh/m3. The maximum ESEs of the ATB unit and the SATB system are 0.71 and 0.30, respectively. The highest ESD of 157.1 kWh/m3 is achieved by the SATB system, which is much higher than the sensible and latent thermal batteries for space cooling. This paper demonstrates a transient supply–demand matching operation scheme of the SATB system in different climates with excellent annual performance, which can facilitate the promotion and development of ATB technology. [ABSTRACT FROM AUTHOR]

Solar energy being intermittent in nature, can provide a sustainable, steady and high density energy source when converted into electrolytic hydrogen. However, in current photovoltaic market trend with 99% conventional single junction PV panels, this cannot be achieved efficiently and economically. The advent of the multi-junction solar cells (MJCs), with cell-efficiency exceeding 46%, has yet to receive wide spread acceptance in the current PV market in form of concentrated photovoltaic (CPV) system, because of its system design complexity, limiting its application scope and customers. The objective of this paper is to develop a low cost compact CPV system that will not only eliminate its application and installation related restrictions but it is also introducing a highly efficient and sustainable photovoltaic system for common consumer, to convert intermittent sunlight into green hydrogen. The developed CPV system negates the common conviction by showing two times more power output than the flat plate PV, in tropical region. In addition, sunlight to hydrogen conversion efficiency of 18% is recorded for CPV, which is two times higher than alone electricity production efficiency of flat plate PV. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct solar-driven thermochemical energy storage in operando fluidized thermogravimetric analyzer is demonstrated. • Excellent long-term stability with energy storage density of more than 85% of the initial value after 100 cycles. • In-situ X-ray diffraction analysis shows the underlying mechanism is attributed to the presence of (AlMgFeMn)O x crystals. • The solar-thermal efficiency of (AlMgFeMn)O x CaCO 3 pellets is significantly improved from 9% to 19%. Calcium looping (CaL) is one of the most promising thermochemical energy storage technologies for high-temperature applications such as next-generation concentrated solar power (CSP) systems. However, most previous investigations have mainly focused on optimizing Calcium-based materials to maintain their reactivity during cycling, while their behavior in reactors under direct solar irradiation has rarely been reported. In this paper, highly efficient and stable direct solar-driven thermochemical energy storage in fluidized reactors is demonstrated. (AlMgFeMn)O x CaCO 3 pellets demonstrated excellent long-term stability with an energy storage density of more than 85% of the initial value after 100 cycles. The underlying mechanism can be attributed to the presence of poly-oxide (AlMgFeMn)O x crystals , which prevent crystallite growth and sintering, as confirmed by in-situ X-ray diffraction analysis. Moreover, the solar-thermal conversion efficiency of (AlMgFeMn)O x CaCO 3 pellets in fluidized bed reactors is significantly improved from 9% to 19% thanks to the considerably increased average solar absorptance and fast reaction kinetics over white (AlMg)O x CaCO 3 pellets. The experimental analysis using an operando fluidized thermogravimetric analyzer (F-TGA) further revealed that the interparticle diffusion control limitation in traditional TGA or fixed bed and localized overheating due to Gaussian distribution of solar irradiation are successfully relieved in a fluidized bed. We further suggest that steam has a positive effect on enhancing reaction kinetics and stability by performing 10 energy storage/release cycles of (AlMgFeMn)O x CaCO 3 pellets under direct irradiation of concentrated light due to the increase of surface area after rehydration and the higher OH reactivity toward CaO. This work paves the way for the application of solar-driven fluidized bed reactors for scalable thermochemical energy storage. [ABSTRACT FROM AUTHOR]

Energy storage plays a vital role in shifting cooling energy load from period of peak demand to that of low demand. This paper reports performance data of an ice-storage unit in solar absorption cooling system for cooling an office space. The cooling system consists of ammonia-water absorption chiller, evacuated tube solar collectors and ice-storage. Experiments were carried out on two consecutive days in each of the month of March and October in Dhahran, Saudi Arabia. The ice-storage unit was charged on the first day and the cool energy discharged on the other day. The results showed average coefficient of performance (COP) of the chiller during charging as 0.43 and 0.47 for the months of March and October, respectively. The results also indicate that the ice-storage can provide a backup time of about 5–6 h, which is sufficient to cool the given space during the early hours of chiller warm-up. [ABSTRACT FROM AUTHOR]

• The off-design model of liquid air energy storage system is established. • The new strategy considers the synergistic regulation relationship between multiple variables. • The cold cycle strategy is helpful to recover cold energy and improve system performance fully. • The thermal cycle strategy achieves better heat coupling and prolongs the discharging time. • The off-design operation domains of the system under different molten salt temperatures are obtained. Liquid air energy storage (LAES) is a large-scale physical energy storage system with high energy storage density. At present, the coupling matching regulation mechanism of the cold and thermal cycles is unclear under off-design conditions, which makes the stable and efficient operation of the LAES system difficult. New multivariable control strategies for cold and thermal cycles are proposed based on the solar aided liquid air energy storage (SA-LAES) system. The study results show the "equal proportion cold recovery" strategy is superior to other strategies, improving the system performance and meeting the demand of the maximum capacity of the charging process. When the liquid air mass flow ratios are 0.7 and 0.4, the air liquefaction ratios increase by 20.20% and 86.43%, and the round-trip efficiency (RTE) values increase by 19.44% and 84.86%, respectively. The new thermal cycle control strategy achieves a good heat coupling matching and maximizes the discharging time and RTE in the zero-carbon environment. Under 70% load and 40% load, the discharging time increase by 16.26% and 53.83%. RTE values increase by 16.28% and 53.84%, respectively. Finally, the operation domains of SA-LAES at different molten salt temperatures are obtained with the optimal cold and thermal cycle strategies. The achievements in this paper will provide valuable reference for the stable operation of SA-LAES under off-design conditions. [ABSTRACT FROM AUTHOR]

The paper aims to demonstrate the improvement of power dispatchability that can be achieved with a suitable integration of Concentrating Solar Power (CSP) and Concentrating Photovoltaic (CPV) plants to mitigate the effects of the variability and intermittency of solar energy. In particular, the CSP–CPV plant analyzed here refers to the design data of the Ottana Solar Facility, which is currently under construction in the industrial district of Ottana (Sardinia, Italy). Since it is very difficult to know the power curves that are going to be required during the operation phases of the hybrid CSP–CPV plant, the present study has been carried out by assuming a reference daily power output curve, which is simply represented by a constant power output. Moreover, two different energy management strategies, fully integrated (F-INT) and partially integrated (P-INT), are analyzed and compared. The results of this study show the advantages of using an integrated management strategy to satisfy a constant power output curve. Optimization of the CSP and CPV power share leads to an effective use of the dispatch capabilities of the CSP plant owing to the TES section, while the CPV plant is fully exploited, especially during the hours of high solar radiation. Comparison of the results achieved with the F-INT and P-INT control strategies demonstrates that the F-INT one leads to better performance both in terms of annual energy production and hours of potential time duration. [ABSTRACT FROM AUTHOR]

Stand-alone photovoltaic (PV) water pumping systems effectively use solar energy for irrigation purposes in remote areas. However the random variability and unpredictability of solar energy makes difficult the penetration of PV implementations and complicate the system design. An optimal sizing of these systems proves to be essential. This paper recommends a techno-economic optimization model to determine optimally the capacity of the components of PV water pumping system using a water storage tank. The proposed model is developed regarding the reliability and cost indicators, which are the deficiency of power supply probability and life-cycle costs, respectively. The novelty is that the proposed optimization model is analytically defined for two-objectives and it is able to find a compromise solution. The sizing of a stand-alone PV water pumping system comprises a detailed analysis of crop water requirements and optimal tilt angles. Besides the necessity of long solar radiation and temperature time series, the accurate forecasts of water supply needs have to be determined. The calculation of the optimal tilt angle for yearly, seasonally and monthly frequencies results in higher system efficiency. It is, therefore, suggested to change regularly the tilt angle in order to maximize solar energy output. The proposed optimal sizing model incorporates all these improvements and can accomplish a comprehensive optimization of PV water pumping systems. A case study is conducted considering the irrigation of citrus trees yard located in Antalya, Turkey. The proposed model is also compared with a computational method and it is shown that sizing results are technically and economically more suitable than computational algorithm according to the applications on a 5-yearly basis. [ABSTRACT FROM AUTHOR]

Wind and solar energy introduced significant operational challenges in a Microgrid (MG), especially when renewable generations vary from forecasts. In this paper, forecast errors of wind speed and solar irradiance are modeled by related probability distribution functions and then, by using the Latin hypercube sampling (LHS), the plausible scenarios of renewable generation for day-head energy and reserve scheduling are generated. A two-stage stochastic objective function aiming at minimizing the expected operational cost is implemented. In the proposed method, the reserve requirement for compensating renewable forecast errors is provided by both responsive loads and distributed generation units. All types of customers such as residential, commercial and industrial ones can participate in demand response programs which are considered in either energy or reserve scheduling. In order to validate the proposed methodology, the proposed approach is finally applied to a typical MG and simulation results are carried out. [ABSTRACT FROM AUTHOR]

• A solar-driven chemisorption refrigeration/cold energy storage system is proposed. • Chemisorption refrigeration and sorption energy storage are coupled together. • The system can efficiently operate at a hot water temperature of above 70 °C. • Cooling capacity can be changed by adjusting the number of reactors in operation. • The system can meet precooling needs of freshly harvested fruits and vegetables. In rural regions, freshly harvested fruits and vegetables cannot be precooled in time, resulting in enormous economic losses. In this paper, a novel solar-driven compression-assisted desorption chemisorption refrigeration/cold energy storage system for refrigerated warehouses is proposed. Compression-assisted desorption allows flexible adjustment of the desorption temperature of composite sorbent to actively adapt to the instable solar hot water temperature. The desorption reaction can increase compressor suction pressure, which helps to reduce power consumption and improve the coefficient of performance (COP). The chemisorption energy storage module completes its regeneration by day and releases cold energy to refrigerated warehouse at night. This module can change the refrigerating temperature depending on the type of fruits and vegetables, superior to the phase change cold storage technology. Therefore, the system can effectively overcome the problems caused by the instability and intermittency of solar energy. According to the performance test results of the reactor, the COP is 5.5 at a hot water temperature of 90 °C, an evaporating temperature of −10 °C and a condensing temperature of 40 °C, which is higher than the 2.6 of the R404A vapor-compression system. Additionally, its refrigerating capacity can be changed by adjusting the number of reactors operating inside the sorption bed, ranging from 1.52 kW to 5.21 kW. Analysis results indicate that the system can efficiently and consistently meet the precooling needs of freshly harvested fruits and vegetables during the picking season. The payback period is less than one year, considering the economic benefits it brings. Ultimately, the novel system is suitable for refrigerated warehouses in sunny rural regions. [ABSTRACT FROM AUTHOR]

• Two novel S-CO 2 Brayton cycle SPT system with compressed CO 2 energy storage. • The thermo- and techno-economy of each system were compared. • The S-CO 2 Brayton cycle with T-CO 2 as the bottom cycle has the highest efficiency. • System combined compressed CO 2 energy storage and heat storage has lower LCOE. Two kinds of S-CO 2 Brayton cycle tower solar thermal power generation systems using compressed CO 2 energy storage are designed in this paper. The energy storage system uses excess solar energy to compress CO 2 near the critical point to a high-pressure state for energy storage during the day, and the high-pressure CO 2 is heated by a gas-fired boiler or the heat of stored high-temperature molten salt at night, so that it enters the turbine for work and drives the generator to generate electricity. The traditional molten salt heat storage scheme and the proposed compressed CO 2 energy storage system model are established with Ebsilon software, and then the equipment selection, structure layout, and parameter design processes are carried out for the energy storage and heating systems. The thermoeconomic and technoeconomic indexes of the three energy storage schemes are calculated under the operating conditions of a typical day. The results show that the efficiency of the combined cycle is higher than that of other organic working fluids when T-CO 2 is used as the bottom cycle working fluid. The integrated scheme of compressed CO 2 energy storage and auxiliary combustion has the highest average daily efficiency (26.62% on summer solstice and 23.04% on winter solstice) and the lowest initial equipment investment. However, due to the additional cost of natural gas, the scheme has the highest levelized cost of energy (LCOE) at $0.1168/kWh. The LCOE of the integrated scheme of compressed CO 2 energy storage and molten salt heat storage was the lowest at $0.1046/kWh. [ABSTRACT FROM AUTHOR]

Abstract: Most medium and small islands of the Aegean Archipelagos face serious infrastructure problems, strongly related with the limited electrical energy available at extremely high cost. On the other hand, the area is characterized by very high wind speeds and abundant solar energy, thus the exploitation of the available renewable energy sources (RES) may significantly contribute to the fulfillment of the local societies energy demand at minimum environmental and macroeconomic cost. However, the stochastic availability of wind energy and the variable availability of solar energy, the daily and seasonal electricity demand fluctuations, as well as the limited local electrical network capacity result in serious restrictions concerning the maximum renewable power penetration. In this context, the present paper investigates the possibility of creating a combined electricity generation facility based on the exploitation of wind or/and solar potential of an area as well as on the utilization of an appropriate energy storage configuration in order to replace the existing thermal power stations with rational investment requirements. For this purpose, the major parameters of the proposed integrated configuration are firstly calculated and its financial viability is accordingly analyzed. One of the main targets of the proposed solution is to maximize the RES exploitation of the area at a minimum electricity generation cost, while special emphasis is given in order to select the most cost-efficient energy storage device available. According to the results obtained the proposed solution is not only financially attractive but also improves the quality of the electricity offered to the local communities, substituting the expensive and heavily polluting existing thermal power stations. [Copyright &y& Elsevier]

• A detailed collector model was set up by using the finite difference method. • A dynamic model was established for absorption chiller with storage. • The average performance coefficient is increased by 3.5% for the proposed system. • Implement the integrated cooling system into a villa district. The use of a solar-powered absorption chiller for residential cooling is impeded by the instability and intermittency of solar energy with time. Integrating the absorption heat storage into the absorption refrigeration alleviates the mismatch between solar sources and the cold demand. This paper investigated a solar-powered absorption chiller with an absorption thermal energy storage system using a dynamic numerical model. The dynamic model is solved according to the nonlinear programming and the second-order iterative numerical integration program. Based on simulation and comparison results, the performance characteristics for the proposed system are discussed. The results indicate that the combination of an absorption chiller and absorption thermal energy storage is feasible. Compared with the reference system, the total refrigerating capacity and average performance coefficient for the proposed system are increased by 4.44% and 3.5%. Finally, the total cold storage capacity of the integrated system can reach 6890.4 MJ/day, which can extend the cooling time to about 14 h. This research provides insight into future work regarding the wide application for solar cooling. [ABSTRACT FROM AUTHOR]

Greenhouses provide a controlled environment that is suitable for plants growth and cultivation. In this paper the maximum temperature change inside the greenhouse is to be reduced by the use of energy storage in a phase change material PCM. A mathematical model is developed for the storage material and for the greenhouse. The coupled models are solved using numerical methods and Java code program. The effect of different parameters on the inside greenhouse temperature is investigated. The temperature swing between maximum and minimum values during 24 h can be reduced by 3–5°C using the PCM storage. This can be improved further by enhancing the heat transfer between the PCM storage and the air inside the greenhouse. [Copyright &y& Elsevier]

Abstract: This paper presents a comparative study of the total melting time of a phase change material (PCM) packed in three containers of different geometric configurations, viz. rectangular, cylindrical and cylindrical shell, having the same volume and surface area of heat transfer. Employing a slightly modified enthalpy method, which enables decoupling of the temperature and liquid fraction fields, the governing equation for one dimensional isothermal phase change is discretized using the Crank–Nicholson finite difference scheme. While the resulting system of algebraic equations for temperature is solved using the Thomas algorithm, the liquid fraction field is updated explicitly using the currently known temperature field. The results are presented for different masses of PCM filling the containers and inlet temperature of the heat transfer fluid (HTF). On the basis of detailed discussion of these results, it is concluded that for the same mass of PCM and surface area of heat transfer, cylindrical shell containers take the least time for equal amounts of energy storage, and this geometric effect is more pronounced with an increase in the mass of the PCM. It is also found that for cylindrical shell containers, an increase in the inlet temperature of the HTF from its lower range of values results in a drastic decrease in energy storage time, while this effect of inlet temperature of the HTF diminishes sharply at higher and higher values. Further, it is observed that as the mass of the PCM in the cylindrical shell container having a fixed surface area of heat transfer increases, the reduction in total melting time due to an increase in the inlet temperature of the HTF becomes more and more pronounced. [Copyright &y& Elsevier]

In the present paper, an attempt has been made to develop a computer model based on transient analysis of the greenhouse. The model predicts room air temperature, storage water temperature and the thermal energy storage effect of a water mass in a low cost, passive greenhouse. Analytical expressions, based on an energy balance for each component, have been derived in terms of climatic as well as design parameters. Numerical computations have been done on typical days for the months from December 1999 to June 2000 at New Delhi. It has been observed that (i) there is a significant thermal energy storage effect of the water mass on room temperature and (ii) TLL, which is found to decrease with an increase in the mass of storage water, varies with month of year. An experimental validation of the developed model has also been demonstrated. The predicted room and water temperature show fair agreement with experimental values. [Copyright &y& Elsevier]

• A novel freshwater, cooling, and power trigeneration system based on solar energy and molten salt storage is designed. • The proposed system aims to satisfy the water and power shortage in a southern city of Iran. • The performance of the system is evaluated under worst weather conditions in summer time. • The system is optimized in four different scenarios to identify optimum operating conditions. In summer, the coastal areas of southern Iran suffer from the freshwater shortage and electricity instability. Meanwhile, this region benefits from the high intensity of solar radiation and the huge potential of brackish water resources. Hence, this paper designs a novel cooling, power and pure water trigeneration system for application in this area to mitigate its energy and water crisis. The proposed system is composed of a solar-based Goswami power and cooling production cycle and a multistage flash seawater desalination process. Moreover, a molten salt heating energy storage unit is used to prove its steady operation under uncertain sunlight condition. A comprehensive parametric study is provided to evaluate the system performance by changing the key variables. The numerical results demonstrate that increasing the pressure ratio from 6 to18 causes 3.3% leads to an increase in system efficiencies and minimum total products cost experiences at the pressure ratio of 12.6. Additionally, as the superheating degree increases from 0 to 10 K, the energy efficiency decreases but the exergy efficiency increases. When the ammonia concentration at the rectifier exit is increased from 0.965 to 0.995, the energy efficiency increases 5%, the exergy efficiency has a decreasing trend from 28% to 25.9%, and the minimum total products cost is 131.2 $/GJ. Furthermore, the exergy efficiency gains its maximum, the energy efficiency has a minimum value, and the total products cost grows with higher values of the minimum approach temperature. Finally, the system is optimized under four different scenarios to identify its best operating condition in each condition: three single-objective and one multi-objective optimization cases. The results of the multi-objective optimization are trade-offs between the ones for single-objective optimization cases. In this case, the net power of 12 MW, cooling capacity of 15.74 kW, and the freshwater of 4.72 kg/s are attainable. [ABSTRACT FROM AUTHOR]

• Thermal storage using powders are hindered by the lack of powder flowability. • Two critical factors governing flowability are temperature and consolidation. • Powder cohesiveness has been measured for different powders. • Powder cohesiveness is enhanced with temperature and consolidation. • Nanosilica coating helps mitigating the loss of powder flowability. Solar technology has shown a keen interest in thermochemical storage to extend its operational timespan beyond a daily basis. Thermochemical solutions are operated by fine powders. Unlike regular granular media, fine powders become cohesive. However, despite the paramount importance of controlling powder flowability to integrate these solutions in solar technology, little research has focused on how powder cohesiveness shapes the flow regime through the storage circuit. This paper investigates two critical factors governing the granular flow through the storage route: temperature and consolidation. The experimental setup emulates the transition powders undergo from silos to reactors. Powders were consolidated before being fluidized at a given temperature, ranging from ambient to 500 °C. Tensile yield strength was then measured for different powders. The results exhibit the expected rising trend in the tensile yield strength of powders as temperature increases. But, interestingly, tensile yield strength skyrocketed when powders were subjected to higher consolidations. Backed by theoretical estimations based on mechanical models, the analysis unveils a cross effect between temperature and consolidation. A combined action that reinforces cohesion by promoting a plastic deformation; worsening, thus, powder flowability. In conclusion, consolidation introduces a multiplying effect on the powder cohesiveness as temperature increases, which represents a serious caveat to solar energy storage technology. To mitigate potential flowability issues, this work explores the use of nanoparticles of silica to layer limestone (calcium carbonate, CaCO 3) particles. The nanosilica coatings turned out to be a very promising solution to preclude the enhancement of cohesion induced at high temperatures. Coated samples showed powder cohesiveness at high temperatures similar to the values obtained at room temperature. A solution that offers a simple and reliable alternative to smooth the flow regime in solid-based energy storage technologies at production environments. [ABSTRACT FROM AUTHOR]

• A novel integration of compressed air energy storage, solar, and desalination units. • Comprehensive thermodynamic, exergoeconomic, and economic analyses of the system. • Multi-objective optimization based on artificial neural network and genetic algorithm. • A precise case study based on real solar radiation and electricity prices in San Fransisco. • Achieving a payback period of 2.67 years with total profit of 112 M$ for the case study. In this paper, a novel dual-purpose green energy storage system with the aim of power and potable water production is proposed and investigated from the thermodynamic and economic points of view. The proposed system is based on an innovative combination of compressed air energy storage with solar heliostat and multi-effect thermal vapor compression desalination units that provides power and clean water without any emissions. This system not only stores low price electricity as compressed air during off-peak times for peak shaving at high demand periods, but it also produces freshwater by recovering the waste heat that is a byproduct of the system at both charging and discharging periods. Exploiting solar energy for increasing the air turbine inlet temperature instead of using the conventional combustion chambers makes the system entirely environmentally friendly. Performing energy, exergy, and exergoeconomic analyses, an artificial neural network algorithm is developed to predict round trip efficiency and total cost rate as the leading indicators for energy and economic performance of the proposed system. Then, the obtained relations are introduced to the genetic algorithm for multi-objective optimization that considers both technical and economic aspects. The round trip efficiency and total cost rate are calculated to be 48.7% and 3056 $/h under the optimal design condition, respectively. Finally, utilizing the proposed system in the case study of San Francisco, United States of America, a total potable water production of 226,782 m3 and power generation of 27,551 MWh in a year with a payback period of 2.65 years were achieved. [ABSTRACT FROM AUTHOR]

• A novel multi-objective optimization model is proposed for a biogas-solar-wind IES. • A multitasking multi-objective optimization algorithm, MO-MFEA-II, is proposed. • Digester heating is applied to improve the efficiency of biogas production. • Online parameter estimation technology is used to boost the efficacy of MO-MFEA-II. The optimal operation of integrated energy systems (IESs) is of great significance to facilitate the penetration of distributed generators and improve its overall efficiency. A grid-connected IES is proposed in this paper for the synergetic interactions of electricity, thermal and gas energy flows, in which the biogas-solar-wind complementarities are fully considered and the digester heating is applied to provide an appropriate temperature for biogas production from anaerobic digestion. Its multi-objective optimization (MOO) model is constructed to optimize the operational cost, carbon dioxide emission and energy loss while considering digesting thermodynamic effects for anaerobic digester and uncertainty of wind and solar power, which is then compared to that of a natural gas-solar-wind IES. Thereafter, we develop an improved realization of multitasking paradigm within the domain of MOO to simultaneously solve the multi-objective operation optimization of the two IESs. In the associated multitasking algorithm, the underlying similarities of distinct optimization tasks are learned online to mitigate the harmful inter-task interactions and thereby facilitate improved convergence characteristics. The efficacy of the proposed multitasking algorithm has been comprehensively assessed on a novel biogas-solar-wind IES and a natural gas-solar-wind IES. Simulation results validated that the proposed IES can be operated in a more cost-efficient and environmentally friendly manner by comparing to the natural gas-solar-wind IES; the developed multitasking MOO algorithm can provide a better performance than other state-of-art multitask and single-task optimization algorithms. [ABSTRACT FROM AUTHOR]

• Hybrid solar solid oxide electrolyzer hydrogen production process is investigated. • The system is capable of producing 50.4 kg of hydrogen per hour. • Rankine cycle has the capability to provide 42.78% of the electrical power. • LFR solar system provides 83% of the required energy in the process. Hydrogen has been hailed as a fuel due to growing energy requirements, as well as environmental considerations. So far, no research has been conducted on the simultaneous use of linear Fresnel collector and solid oxide electrolyzer cell with thermochemical storage tanks to produce hydrogen. In this paper, a newly developed system with the purpose of producing a constant flow of hydrogen using solar energy is proposed. The system includes four main subsystems. These subsystems include linear Fresnel solar collectors, solid oxide electrolyzer cell, Rankine power generation cycle, and thermochemical energy storage unit. Modeling of subsystems is done using MATLAB and Aspen HYSYS software. The system is studied from the perspective of the first and second laws of thermodynamics. Also, the effect of thermal energy storage with different periods on the overall performance is investigated. Four thermal energy storage scenarios and their effect on energy and exergy efficiency, solar fraction, thermochemical storage tank dimensions, and auxiliary heater load variations are presented as results. The system is capable of producing 50.4 kg of hydrogen per hour. Results show that the Rankine cycle has the capability to provide 42.78% of the electrical power consumed by the electrolyzer. Also, with the increase of thermal energy storage period up to one year, the energy and exergy efficiencies will reach to 20.17% and 13.73%, respectively. In this case, 0.83 of the energy required for the system, is supplied by the solar energy. [ABSTRACT FROM AUTHOR]

• Thermal analysis helps to choose the best performance enhancement technique. • Performance augmentation methods try to minimize thermal losses from collectors. • Use of nanofluids significantly enhances the thermal performance of collectors. • Integration of collectors with PCMs can both increase efficiency and save energy. Solar energy as a plentiful and environment-friendly source of energy has an acceptable potential in nearly most of the regions around the world. Thermal technologies are commonly used to provide heat requirements of different domestic, agricultural, residential, and industrial applications from the sun. This paper reviews thermal performance enhancement techniques of the most widely-used low-temperature solar collectors (LTSCs) including flat-plate collectors (FPCs), evacuated tube collectors (ETCs), and compound parabolic concentrators (CPCs) by introducing challenges and discussing future research potentials. In this regard, energy analysis of each collector type along with the latest advancements to boost the heat collection capability of the LTSCs reported in the previous studies is presented. The discussed methods in this study broadly cover structural modifications, absorber coatings, integration with reflectors, using alternative working fluids including nanofluids, and employing thermal energy storage (TES) systems. This comprehensive review is reflecting the level of technical maturity of each type of LTSCs and is expected to serve scientists, engineers, and developers with the latest achievements in this technology. [ABSTRACT FROM AUTHOR]

• Solar transcritical carbon dioxide Rankine cycle with compressed air energy storage. • Evaluation of the system performance in the charging process of compressed air. • Air compression heat recovery for the enhancement of system performance. Solar thermal power generation is a promising technique in renewable energy utilization with the advantages of techno-economic, energy storability, power continuity, and stability. The present paper designed a solar transcritical carbon dioxide Rankine cycle integrated with compressed air energy storage, which could resolve the impact of solar energy intermittence and enhance the technical flexibility in solar thermal power and storage. An original system configuration with heat recovery of the compressed air was proposed to improve the system performance. The effects of carbon dioxide mass flow rate and heat source temperature on the performances of Rankine cycle and energy storage system were evaluated in the charging process. The results indicate that the air compression heat recovery could enhance the Rankine cycle performance, and weakened the negative effect of pump power at high carbon dioxide mass flow and air storage pressure. As the carbon dioxide mass flow and the air storage pressure increase, the system performance decreases severely due to the negative effect of pump power. The positive impact of expander power on system performance is more evident at the low mass flow of carbon dioxide, especially at high air storage pressure. As the heat source temperature decreases, the negative effect of pump power on the system performance gets severe, especially at the high mass flow. The air storage pressure has a more visible impact on the exergy efficiency at the low mass flow. Compression heat recovery results in a low exergy efficiency of the energy storage system in the initial charging process. The exergy efficiency is also affected by the air exergy in the isothermal storage chamber with a constant volume with a rapid heat transfer from the chamber to the environment. [ABSTRACT FROM AUTHOR]

• Mechanical energy storage systems are very efficient in overcoming the intermittent aspect of renewable sources. • Flywheel, pumped hydro and compressed air are investigated as mechanical energy storage. • Parameters that affect the coupling of mechanical storage systems with solar and wind energies are studied. Mechanical energy storage systems are among the most efficient and sustainable energy storage systems. There are three main types of mechanical energy storage systems; flywheel, pumped hydro and compressed air. This paper discusses the recent advances of mechanical energy storage systems coupled with wind and solar energies in terms of their utilization. It also discusses the advances and evolution in each type and compares them in terms of performance, capacity, response and utilizations. The reviewed studies exhibit all parameters that affect the performance of each storage type in which the configuration of the system has the major effective role. Choosing the suitable mechanical storage type depends on the requirements of each application such as using the flywheel for short duration applications. If long duration is needed, then it is preferred to use either pumped hydro or compressed air storage systems, knowing that the former has higher efficiency while the latter provides a faster start up. For the sake of the environment, it is recommended to use the adiabatic or isothermal compressed air storage. In all cases that combine MESSs with solar or wind energy, the series connection is preferred in order to provide stability and better control strategy. [ABSTRACT FROM AUTHOR]

• Seasonal solar energy storage using the hybrid thermochemical sorption technology. • Maximise recovery and usage of low temperature solar heat for building heating. • Compared the system performance that used a compressor or an electric heater. • Using a compressor efficiently improved the storage capacity and energy efficiency. • Carbon intensity of the studied system was much lower than conventional systems. The present paper investigated the seasonal solar thermal energy storage (SSTES) using solid-gas thermochemical sorption technology that has inherently combined function of heat pump and energy storage. The thermochemical reactions that can discharge heat at a higher temperature usually requires a relatively higher desorption temperature during charging process, which could be problematic to efficiently recover solar energy in high-latitude regions like the UK when using the most mature and economic solar thermal collector (flat-plate or evacuated tube type). The present work studied two hybrid concepts where an electric-driven compressor or an electric heater was introduced to supplement the thermochemical desorption process in terms of pressure rise and temperature lift, respectively, when the available solar heat was not sufficiently high. The SrCl 2 -8/1NH 3 chemisorption was selected from 230 ammonia-chemisorption reactions due to its suitable adsorption/desorption temperature and large energy storage density. The performance of two hybrid systems using SrCl 2 -8/1NH 3 chemisorption were evaluated and compared to determine the optimal solution. The results revealed that the hybrid thermochemical sorption with a compressor substantially improved the storage capacity compared to that with electric heater. With a compression ratio of 4, the SSTES system with 20 m2 solar collector under the weather condition of Newcastle upon Tyne can store 3226.8 kWh chemisorption heat in summer by charging 4465.4 kWh solar heat and 848.2 kWh electricity, indicating 60.7% storage efficiency; the corresponding energy density based on the overall system volume is 147.3 kWh/m3. Because of using the renewable solar heat and low carbon intensity electricity in summer, the proposed hybrid SSTES system has noteworthy reduction on carbon emission compared to gas boiler and conventional heat pump. [ABSTRACT FROM AUTHOR]

• The absorption thermal energy storage cycles and systems are presented. • The integrated absorption thermal energy storage and systems are reviewed. • The working pairs for absorption thermal energy storage are discussed. • Perspectives for the development of absorption thermal energy storage are forwarded. Due to the high energy storage density and long-term storage capability, absorption thermal energy storage is attractive for the utilization of solar energy, waste heat, off-peak electricity, and etc. In recent years, absorption thermal energy storage has been intensively studied from thermodynamic cycles, working pairs, and system configurations for various purposes. In this paper, first, the absorption thermal energy storage cycles are discussed in detail. Then, storage integration with a conventional absorption chiller/heat pump, which can be driven by solar energy or compressor, is presented in a way of valorizing absorption systems. Next, working pairs including water-based working pairs, ammonia-based working pairs, alcohol-based working pairs, and others are reviewed. Finally, future perspectives are forwarded to realize the absorption thermal energy storage in practice, which encompasses developing of new absorption cycles and system configurations, new working pairs, and new reactor and heat exchanger design. [ABSTRACT FROM AUTHOR]

• Hybrid solar-hydro-hydrogen-fuelcell is developed in net zero energy building. • Solar power, hydro power, and load demand modeled by Gaussian distribution. • Hydrogen storage and fuelcell smooth out energy volatility and uncertainty. • Solar-hydro systems compensate each other during summer and winter. • Optimal power and operation pattern is found for hydrogen, fuelcell, solar units. The net-zero energy buildings are often supplied by renewable resources and energy storage systems. These energy resources have different seasonal and daily patterns of power production. Their output power is also uncertain. This paper aims to study these issues including daily-seasonal operation patterns, uncertainty, and cogeneration of various renewable resources and storage systems. These issues are investigated at net-zero energy building supported by renewable resources (i.e., solar energy, hydro energy, and fuelcell) and energy storage systems (i.e., hydrogen storage system). The uncertain parameters of the model are solar-hydro-load powers. The model minimizes the investment cost on solar system. The plan finds optimal sizing and operation for solar, hydro, hydrogen, and fuel-cell. The cooperation of hydrogen storage and fuelcell is optimized to level the uncertainty. The surplus of energy is fed into water electrolyzer to produce hydrogen and the fuelcell consumes the hydrogen to produce electricity. The seasonal operation is dealt by cogeneration of hydro-solar systems. The proposed plan installs 73 kW solar panel. The hydrogen storage system is charged at hours 7–17. When hydro power is increased to 39 kW, the building does not need the solar energy. The proposed model decreases the Carbon Dioxide by about 39546 kg. The model also reduces the total cost by about 50.3%. [ABSTRACT FROM AUTHOR]