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The solar collector is the heart of any solar energy collection system designed for operation in the low to medium temperature ranges. So, an efficient design of solar collector system, giving optimum performance is required. Though system performance is optimized by many different techniques, however, intelligent system design is an useful technique to optimize the efficiency of such systems. One of the intelligence techniques is Artificial Neural Network (ANN), and it is used in modeling, simulation and control of the system. ANN tool is faster and more accurate to solve complex and nonlinear problems as compared to other conventional techniques. ANN technique is applied in the field of Science, Engineering, Medicine, Defense, Business and Manufacturing etc. The main task of ANN tool is training of structure, which is done by collected experimental data of solar energy systems and in this method separate programming is not required as in other conventional methods. The aim of this study is to review the applications of ANN to predict the performance of solar energy collector and to identify the research gap for future work. Published research works presented in this paper, show that the ANN technique is very appropriate tool to predict the performance of solar collector systems [ABSTRACT FROM AUTHOR]

Accurate information on global solar radiation is essential to design and operate the systems that are based on solar energy. However, global solar radiation measurement is very rare while the measurements of other meteorological parameters such as air temperature, relative humidity, sunshine duration and precipitation are common in meteorological stations all around the world. Therefore, modelling global solar radiation is an important issue to fill the gaps in database and to estimate global solar radiation in places where global solar radiation measurement is not available. There are many different approaches in the literature for modelling global solar radiation. Two new methodologies are presented in this paper to develop parametric models for estimation of daily global solar radiation based on sunshine duration and relative humidity as well as a review of fourteen different already exist parametric models which are based on air temperature, maximum temperature, minimum temperature, precipitation, sunshine duration and relative humidity. The proposed models improve the estimation results of the other fourteen models with average mean absolute error (MAE) of 0.947 MJ/m 2 for Adana station, 1.086 MJ/m 2 for Göksun station, 1.074 MJ/m 2 for Tarsus station and 1.060 MJ/m 2 for whole study area. Hence, the proposed models which significantly approximate to measurements from pyranometers can be useful for the modelling global solar radiation in Eastern Mediterranean Region. [ABSTRACT FROM AUTHOR]

Solar Energy is available in abundance and can be easily extracted using solar cells along with regular maintenance of solar panels. However, the efficiency of solar cells which is fairly low, is further affected by factors such as orientation of the panel, shade, wind speed, ambient temperature, precipitation and dust deposition. Especially, the maintenance of solar panels is challenging on account of soiling. Presently, manual and water-based cleaning solutions are generally used to remove the debris accumulated on the panels. In this paper, a detailed review of soiling prevention methods is presented with a view to increase the energy capture from solar panels. The technical details of an indigenously developed automated water-free cleaning device to remove soiling over the solar panels, is then discussed. The energy capture over the course of a month for PV panels regularly cleaned using automated solar panel cleaning solution is compared with that of the energy capture using soiled panels in a local solar panel installation, and the increased yield is measured. [ABSTRACT FROM AUTHOR]

Solar energy systems (SESs) are considered as one of the most important alternatives to conventional fossil fuels, due to its ability to convert solar energy directly into heat and electricity without any negative environmental impact such as greenhouse gas emissions. Utilizing nanofluid as a potential heat transfer fluid with superior thermophysical properties is an effective method to enhance the thermal performance of solar energy systems. The purpose of this review paper is the investigation of the recent advances in the nanofluids’ applications in solar energy systems, i.e., solar collectors (SCs), photovoltaic/thermal (PV/T) systems, solar thermoelectric devices, solar water heaters, solar-geothermal combined cooling heating and power system (CCHP), evaporative cooling for greenhouses, and water desalination. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the current state of the developments in sun position sensors used in solar technologies such as photovoltaic modules, satellites, solar collectors and other applications. The working principles and geometric designs of several types of sun position sensors are discussed in detail. The studio considers the evaluation of the advantages and limitations of different design requirements such as accuracy, solar tracking errors, desired properties, field of view (FOV) and commercialization, and the evaluation of outer parameters that affect the performance of sun position sensors (climatic conditions: solar radiation, contamination, and temperature); in order to combine the technologies, increase the efficiency and expand the use of sun position sensors. On the other hand, it was determined that the main barriers that this technology faces are: cost-effectiveness, the operational range of temperature and the effective data transmission, so the future researches should be concentrated around these issues. [ABSTRACT FROM AUTHOR]

The potential of solar energy is very promising. This type of energy is clean and derived from a sustainable source. The only significant disadvantage of this source of energy is its absence during the night. A potential solution would be to create a heat reservoir to be used once the sun has set. This principle is already being applied in solar power plants with the help of molten salt. The molten salt's beneficial thermal characteristics allow power production to continue even past the normal operating hours. In this paper, this principle along with others will be used to create a theoretical method of water purification utilizing molten salt. Additionally, the thermal characteristics of molten salt will be established and a link between stored energy and the maximum possible output of water will be recognized. Different nanoparticle additives (SiO 2 , Al 2 O 3 , TiO 2 , SiO 2 -Al 2 O 3 ) at different concentrations (0.5 wt, 1 wt, 1.5 wt) will also be examined and compared to clarify if they have any effect on the output yield during water purification. It will be seen that some specific mixtures possess thermal properties with more potential compared to others when contrasted with the base mixture of molten salt [NaNO 3 (60%)-KNO 3 (40%)]. These results show promise and will hopefully help address the issue of the severe deficiency of clean drinking water in many countries with the enhancement of the thermal capabilities of molten salt. [ABSTRACT FROM AUTHOR]

The efficiency of the photovoltaic (PV) system is directly proportional to the solar energy. The maximum efficiency from the PV systems can be achieved if the panel is kept perpendicular to the direction of the radiations of sun. Hence, in order to achieve maximum concentration, radiation and efficiency of the PV cell, tracking of the position of the sun with accuracy is extremely important. The various methods of sun tracking system have been discussed which includes two axes, one axis, polar axis, open loop, closed loop, hybrid model, azimuth and tilt roll mechanism. The comparison of existing solar tracking systems and methods has also been discussed. In this paper, various existing solar tracking systems in terms of the controller used like PLC, microcontroller, FPGA to design the system and their economic assessment have been studied. It is concluded that two axis solar tracking systems has more power gain with respect to fixed systems. The microcontroller based tracking system with same size, capacity and location as of PLC based systems are more economic. [ABSTRACT FROM AUTHOR]

This paper presents a comparative study of the experimental analysis of two heat pipe solar collectors with different numbers of heat pipes and a flow-through collector. For this purpose, three collectors were designed, constructed and tested side-by-side under various environmental conditions. In this study the three collectors selected were: first, a collector with six heat pipes, type(I); second, a collector with twelve heat pipes, Type (II); and third, one flow-through solar collector, type (III). These collectors were simultaneously tested outdoor according to ASHRAE standard 93–1986. Tests showed that the efficiency of collector type (II) was higher than the other two. The thermal efficiency of flow-through solar collector (III) at mid-day was higher than collector type (I); however, the efficiency of collector type (I) was higher than the conventional collector type (III) in the morning and in the afternoon. There are two methods to increase the efficiency of heat pipe collectors, the first is to increase the number of heat pipes and the second is to increase the effective absorber area by proper design of the heat pipe condenser. [ABSTRACT FROM AUTHOR]

Heat based vapour absorption cooling technology is the most appropriate, efficient and eco-friendly way of harnessing solar heat energy, as many cooling load requirements are always in phase with the accumulated solar heat. The performance improvement of such systems has currently become a high research priority, to ensure conservation of electrical energy. Performance of these systems depends on two important factors: i) selection of suitable working fluid pair and ii) adopting appropriate configurations and multiple cascaded ‘effects’ of the absorption cycles. The Thermodynamic analysis (TDA) or the first law analysis is the broad indicating tool to predict the performance behavior and suitability of a vapour absorption system for a particular application. In the present work, a detailed literature survey has been conducted on various water based working fluid pairs and their cascaded effects; single-effect, double-effect, triple-effect, 1.5-effect and half-effect vapour absorption cooling systems based on TDA. This review paper focuses on two areas: (1) the importance of conducting TDA and choosing right parameters in TDA for performance enhancement in order to overcome the drawbacks of conventional systems. This will help in finding out system for solar based applications, air-cooled applications and determining solutions to overcome crystallization, corrosion, compactness and initial cost; and, (2) as generator temperatures represent the amount of solar heat energy required, considered as key parameter. For various water based vapour absorption systems, the possible range of generator operating temperature requirements and its corresponding attainable COP values has been reviewed and tabulated. This review data can serve as a source of reference in selecting a suitable solar collector with available fluid pair and configuration or vice-versa. [ABSTRACT FROM AUTHOR]

India receives sun's energy over 300 days a year most of the time. About 5000 trillion kWh per year sun's energy is incident over India's land area. Theoretically, a small fraction of total incident solar energy can meet the entire country's power requirements. There are many government schemes to promote solar power generation. The government of India initiated solar PV/BIPV policies to encourage industries and individuals to use solar energy powered systems for electricity generations. This article provides an overview of the solar energy status and application of BIPV system in India. It includes an assessment of the region's solar energy potential and solar PV/BIPV installed capacity. This paper gives a brief description barriers and challenges facing solar BIPV development in India. This study also provides the solar PV/BIPV policies and recommendations with reference to the Indian context. [ABSTRACT FROM AUTHOR]

In this paper we study a community or firm considering to diversify its investment in two distinct renewable energy technologies, namely wind and solar PV electricity. We assume technological learning curves as a function of cumulative capital investment. A real options approach is applied as it takes into account uncertainty about prices and learning, as well as irreversibility associated with investment decisions. We investigate three different cases, dealing with uncertainty about future electricity prices, and uncertainty about the speed with which learning drives the costs of wind and solar electricity down. We assess the minimum threshold for the stochastic price and the maximum electricity production cost that makes it optimal for the firm to invest in the two technologies. The results show that the learning rate affects the option to invest in but reducing critical threshold for exercising it. The greater the amount of capital invested, the more learning stimulates earlier exercising of the option to invest. The firm will then anticipate the option to invest and exercise it for lower critical threshold values if all capital is invested in one technology. If capital investment is diversified, the option should be exercised at a higher critical threshold. More uncertainty in energy prices or technology costs postpones the option to invest. Although investing in both solar and wind may be profitable under particular conditions of price and cost uncertainty, the theoretically optimal strategy is generally investing in only one technology, that is, solar or wind, depending on their relative initial costs and learning rates. This suggests that the practice in most countries of diversifying renewable energy may reflect a mistaken strategy. [ABSTRACT FROM AUTHOR]

The Rankine cycle is considered the most common and competitive power generation cycle to produce electricity from solar thermal energy. This paper reviews the work done on the solar Rankine cycle systems for power generation and focuses on the working fluids investigated in the literature and the application of these systems in water pumping and water desalination. [ABSTRACT FROM AUTHOR]

In the last decade the demand of power in India has increased manifold, therefore Government has announced the National Solar Mission of generating 100 GW of solar power up to 2022. Around 60% of the total National Solar Mission target is allotted to the national/international large-scale solar power developers/investors. Hence, it becomes important to know the ground reality of large-scale solar PV developers/investors. This paper deeply analyzes the key barriers and bottlenecks faced by solar power developers in achieving the target and their growth. This article also suggests some motivational factors of solar energy which play an important role in attracting large solar players around the world to invest in Indian subcontinent. It concludes by highlighting some key policies of the Government that can help in addressing some identified barriers in order to ensure a secured sustainable energy future of India. [ABSTRACT FROM AUTHOR]

The Northeast region of Brazil has low levels of human development and a marginal environment subject to chronic water scarcity. This paper assesses the potential impacts of bioenergy production from local varieties of castor oil plant and jatropha that could reduce the import of energy in the region, while developing its economy. Biodiesel systems based on these crops can be suitable for the Northeast region as they have low water needs, and are either indigenous or have shown excellent adaptation to the local climate. Apart from biodiesel production, the residue from their processing can be a valuable resource usable for biogas production and bio-fertilizers. Using the ecosystem services approach, five land management alternatives are compared: (i) Caatinga woodland (a type of dry savannah native to the region), (ii) a scheme of local jatropha varieties and vegetation for Caatinga forest restoration, (iii) a crop rotation scheme of castor oil plant and cowpeas, (iv) cowpea mono-cropping, and (v) pasture. Based on the analysis of secondary data, some provisioning and regulating services were assessed quantitatively, while others qualitatively. The results suggest that the conversion of (i) cowpea mono-cropping to a rotation of cowpeas and castor and (ii) degraded pastures to a jatropha-Caatinga forest restoration scheme can provide a bundle of provisioning, regulating and supporting ecosystem services. Feedstock for bioenergy is the most important ecosystem service derived from these multi-functional landscapes. In particular converting pasture to a jatropha-Caatinga forest restoration scheme could provide per hectare 0.7 t of oilseeds for biodiesel production and 1.8 GJ of usable energy, in the form of biogas from the residual seedcake. The castor-cowpea rotation scheme could provide per hectare 1.5 t of oilseeds for biodiesel production together with 2.2 GJ of usable biogas energy, per hectare. [ABSTRACT FROM AUTHOR]

PV power plants have been built by public or private funds along some sections of the Korea Expressways to generate electricity since the early 2010s, but since the national highways have not been allowed to analyze potentials of the solar power generation based on by law or national standards, we aim at setting up new siting criteria to support decision makers to implement solar energy power generation projects on the national highways. This paper presents the formulation of siting criteria for photovoltaic (PV) power generation projects on the national highways in South Korea, which generate and use renewable energy for purposes such as traffic-facility operation. The feasibility of using candidate sites of the potential projects, selected according to the formulated criteria, in future solar highway projects is determined. An investigation of a database of spatial information of unused-highways was conducted. These data were set as the basic inputs for better-selecting with the project site criteria. The final formulated criteria were used to select two candidate sites and simulations of the topographic conditions, solar irradiance, and shade were performed to estimate the power-generation capacities of the candidate sites. In a feasibility analysis, each candidate site demonstrated an electricity-generation capacity more than 1 MW. These results can help in establishing PV power generation projects in South Korea using the national highways with a total length of about 140,000 km as the objective spatial data in the project-planning stage. Furthermore, it promotes the expansion of renewable energy supply sources in South Korea and elsewhere in the world. [ABSTRACT FROM AUTHOR]

Morocco imports about 96% of its required energy needs. Solar energy, as one of the most abundant and valuable renewable energy alternatives in the country, offers interesting opportunities for Morocco. In order to minimize its strong foreign energy dependence, Morocco hosts actually the largest Concentrated Solar Power (CSP) using parabolic trough collectors (PTC) as a technology for converting solar irradiation into thermal energy for electricity generation. The purpose of this paper is to assess the thermal performance of this technology and the potential projects concerned by Moroccan Solar Plan. A physical model is developed to determine flow parameters and heat transfer applied to PTC technology. Annual simulations in six climatic regions in Morocco were carried out. Several suggestions were drawn with regards to the design and parametric studies effectuated under Ouarzazate CSP project. It is found that the location and the climate are determinant parameters on the global performance of the parabolic trough solar collectors. [ABSTRACT FROM AUTHOR]

The conversion of solar energy into electricity is a viable response to address most of world's energy problems. Among the parameters affecting the performance of both photovoltaic (PV) cells and concentrating solar power (CSP) systems include their orientation and tilt angle with respect to the sun. Solar trackers (ST) are ideal devises for efficiency improvement. This paper aims to review the most commonly used ST and identify the systems that offer benefits such as greater efficiency, greater tracking accuracy, easy installation and cost effectiveness. There are mainly two types of ST viz. single and double axis ST. The optimization of these devices requires cumbersome specifications to avoid potential tracking errors that often lead to their poor performance. These specifications cannot be fulfilled by simple tracking methods due to different sources of tracking errors such as the misalignment of the tracking fixture, the level of pollution of the area, the shading of the sensors, the types of control schemes involved, the auxiliary units of the system, the lack of maintenance as well as the imperfection and power mismatch of connecting grids. The study reveals that double axis ST in form of polar-axis and azimuth/elevation featuring the solar movement models and the dynamic closed loop feedback control are the most effective and generally give more than a 40% improvement in energy return compared to fixed PV panels. Moreover, large systems significantly reduce the costs and save on materials. The energy consumed by the moving fixtures is mostly low (2–5% of the collected energy) but this could be higher if no optimization is performed. Lastly, all the hardware and software energy saving parameters must be optimized right from the early stages of the development of the system to prevent materials wastage and the energy over-consumption by the tracking units. [ABSTRACT FROM AUTHOR]

The technology of photovoltaic power generation has been increasingly regarded in many countries as an alternative to reduce the environmental impacts associated with climate changes and dependence on fossil fuels. Countries such as Germany and other European countries have been developed specific regulatory mechanisms to encourage its use either by government programs or by financial and/or tax incentives. In Brazil, despite the large existing solar potential, the encouragement to technology is still incipient. This paper aims to demonstrate the key aspects of the evolution of regulatory incentives to use photovoltaic solar energy in Brazil and present the technologies and characteristics of photovoltaic power generation. [ABSTRACT FROM AUTHOR]

Irrigation is one of the essential unit operations for agriculture and Sudan as an agricultural country with rich natural resources has an urgent need to optimize the utilization of energy, water, and land in a most sustainable way. The cost-effective irrigation pathway utilizing one of the clean energy technologies such as solar energy would contribute significantly to the sustainable development of agricultural sector in Sudan. This paper is intended to investigate the most cost-effective solar water pumping system for irrigation in Sudan. Three solar irrigation pumps were considered based on the collector configuration and type of energy conversion to include two thermal and one photovoltaic pump; parabolic trough pump (PTP), concentrating dish pump (CDP), and photovoltaic pump (PVP). Levelized energy cost (LEC) was used in this study as the economic indicator for the feasibility of solar water pumping systems. A comparative assessment model was developed based on weather conditions of Sudan and sensitivity analysis was conducted to study the effect of design parameters, weather conditions, and interest and inflation rates on the LEC of solar water pumping systems. The resulted LECs for PVP, CDP, and PTP in the base case were found to be 0.033 $/kWh, 0.062 $/kWh, and 0.075 $/kWh, respectively. PVP is the most feasible pathway among solar irrigation pumps in Sudan, and its initial cost per unit hydraulic power capacity is 1351 $/kW, compared to 4072 $/kW and 4884 $/kW for CDP and PTP, respectively. [ABSTRACT FROM AUTHOR]

Concentrating photovoltaic thermal (CPVT) collectors and systems are very popular in both domestic and industrial solar energy applications. CPVT collectors provides incomparably greater thermal and electrical outputs compared to stand alone PV or hybrid PVT systems as incoming solar energy is maximised inside the unit via energy-efficient concentrators. Within the scope of this paper, a comprehensive review on CPVT collectors and systems is proposed. For an easier assessment of the findings through state-of-the-art analyses on CPVT collectors, the review is presented in a thematic way. Historical overview of the technology is followed by the detailed description of a CPVT collector with main system elements and thermodynamic performance definitions. The review also covers thermal and electrical performance analysis of CPVT collectors using water or air as working fluid, analytical, numerical, simulation and experimental works for performance evaluation of different design configurations of CPVT systems and qualitative analysis of electrical and thermal energy generation. The impacts of concentrator type and concentration ratio on system efficiency, operating temperature and coefficient of performance (COP) are analysed in detail. It is observed from the findings that CPVT collectors are promising devices in market, and they have a good potential to be competitive with conventional power generation systems in the near future. [ABSTRACT FROM AUTHOR]

Cameroon produces 1292 MW of electricity out of which 57% is through hydraulic resources and the remaining 43% through fossil fuels resources. The access to this electricity is limited to 10% of population in the rural areas and 50% in the urban areas. To meet the demand of electricity for domestic purpose as well as for businesses, farms and manufacturing, the squeeze on resources will become unsustainable unless renewable resources become part of the mix. In this paper, the review of Building Integrated Photovoltaic (BIPV) systems and its potential in the tropical region is presented. An analysis is made for a residential apartment fitted with BIPV as roof top in tropical climate of Cameroon to meet principle energy demand of 3 kW per day. Modelling of the system is done to predict the indoor air temperatures and humidity (IATH) considering all the internal heat sources and thermal insulation of the envelope. The analysis shows that such system is capable of reducing annual primary energy consumption from 79.58 kW h/m 2 to 13.64 kW h/m 2 in addition to reduction in the amount spent on building materials for structured roof and the labour. [ABSTRACT FROM AUTHOR]

Poor air quality from coal combustion adversely impacts human health including mortality and morbidity effects on respiratory, cardiovascular, nervous, urinary, and digestive systems. However, the continued use of coal are no longer necessary to provide for society's electrical needs because of advances in solar photovoltaic (PV) technology. In order to inform health policy this paper reviews the data for quantifying the lives saved by a replacement of U.S. coal-fired electricity with solar PV systems. First the geospatial correlation with coal fired power plants and mortality is determined for the U.S. at the state level. Then, current life cycle mortality rates due to coal combustion are calculated and current energy generation data is collated. Deaths/kWh/year of coal and PV are calculated, and the results showed that 51,999 American lives/year could be saved by transitioning from coal to PV-powered electrical generation in the U.S. To accomplish this, 755 GW of U.S. PV installations are needed. The first costs for the approach was found to be roughly $1.45 trillion. Over the 25 year warranty on the PV modules the first cost per life saved is approximately $1.1 million, which is comparable to the value of a human life used in other studies. However, as the solar electricity has value, the cost per life is determined while including the revenue of the solar electric generation using a sensitivity analysis on the value of the electricity. These results found that for most estimations of the value, saving a life by offsetting coal with PV actually saved money as well, in some cases several million dollars per life. It is concluded that it is profitable to save lives in the U.S. with the substitution of coal-fired electricity with solar power and that the conversion is a substantial health and environmental benefit. [ABSTRACT FROM AUTHOR]

Due to the increasing awareness of environmental and social issues, many practitioners and researchers have paid much attention to the sustainable supply chain management (SSCM) in recent years. Sustainable supplier selection is one of the most critical activities in the SSCM which can affect supply chain performance. However, the previous literature rarely considers the interrelationships between economic, environmental, and social evaluation criteria in the supplier selection. Moreover, the effect of the criteria importance on the criteria interrelationships is scarcely discussed in previous researches. To deal with these problems, a novel integrated methodology is developed in this paper. The proposed method integrates the merit of pairwise comparison method in determining relative importance, the strength of decision making trial and evaluation laboratory (DEMATEL) in manipulating the complex and intertwined problems with fewer data, and the rough number's advantage in flexibly dealing with vague information. A case study in a solar air-conditioner manufacturer is provided to show the feasibility and effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

Power-to-heat solutions like heat pumps and electric boilers are foreseen to be possible future tools to stabilise international power markets with high proportions of variable power supply. Temporary low cost electricity can be used for heat generation at times with high availability of wind and solar power through substitution of ordinary heat supply, hence contributing to increased energy system sustainability. Power-to-heat installations in district heating systems are competitive due to low specific investment and installation costs for large electric boilers, heat pumps, and heat storages. Several large-scale heat pumps were installed in Swedish district heating systems during the 1980s, since a national electricity surplus from new nuclear power existed for some years. The aim of this paper is to summarise the accumulated operation experiences from these large Swedish heat pumps to support and facilitate planning of future power-to-heat solutions with heat pumps in district heating systems. Gained experiences consider; installed capacities, capacity utilisation, heat sources used, refrigerant replacements, refrigerant leakages, and wear of mechanical components. The major conclusion is that many of the large thirty-year-old heat pumps are still in operation, but with reduced capacity utilisation due to internal competition from waste and biomass cogeneration plants in the district heating systems. [ABSTRACT FROM AUTHOR]

The prediction of global solar radiation for the regions is of great importance in terms of giving directions of solar energy conversion systems (design, modeling, and operation), selection of proper regions, and even future investment policies of the decision-makers. With this viewpoint, the objective of this paper is to predict daily global solar radiation data of four provinces (Kırklareli, Tokat, Nevşehir and Karaman) which have different solar radiation distribution in Turkey. In the study, four different machine learning algorithms (support vector machine (SVM), artificial neural network (ANN), kernel and nearest-neighbor (k-NN), and deep learning (DL)) are used. In the training of these algorithms, daily minimum and maximum ambient temperature, cloud cover, daily extraterrestrial solar radiation, day length and solar radiation of these provinces are used. The data is supplied from the Turkish State Meteorological Service and cover the last two years (01.01.2018–31.12.2019). To decide on the success of these algorithms, seven different statistical metrics (R2, RMSE, rRMSE, MBE, MABE, t-stat, and MAPE) are discussed in the study. The results shows that R2, MABE, and RMSE values of all algorithms are ranging from 0.855 to 0.936, from 1.870 to 2.328 MJ/m2, from 2.273 to 2.820 MJ/m2, respectively. At all cases, k-NN exhibited the worst result in terms of R2, RMSE, and MABE metrics. Of all the models, DL was the only model that exceeded the t-critic value. In conclusion, the present paper is reporting that all machine learning algorithms tested in this study can be used in the prediction of daily global solar radiation data with a high accuracy; however, the ANN algorithm is the best fitting algorithm among all algorithms. Then it is followed by DL, SVM and k-NN, respectively. • Comparison of four machine learning algorithms in the prediction of daily global solar radiation. • Discussion of the performance success of the algorithms with seven metrics. • Different regions come different algorithms to the fore in terms of prediction success. • ANN is generally presenting better prediction results in comparison with those of DL, SVM, and k-NN. • k-NN algorithm is giving the worst prediction results for almost all metrics. [ABSTRACT FROM AUTHOR]

This paper offers perspectives on the development of low-carbon energy technology in Brazil, pinpointing changes that have occurred since our former publication in 2011. It takes a fresh approach in terms of how likely Brazil will achieve its Nationally Determined Contributions Commitments in the energy sector. Many countries have implemented national climate policies to accomplish their pledged NDC and contribute to the temperature objectives of the Paris Agreement on climate change. Based on official reports and databases of energy development projections in Brazil and the socioeconomic context, we discuss what can be expected for the future of the Brazilian energy sector, the probability of implementing selected technologies, and the prospects of reaching the NDC targets for 2025 and 2030. In addition, this paper provides an overview of the current stage of development of these technologies, main directions, and bottlenecks in Brazil. Analyses have shown that the Brazilian renewable matrix tends to remain significant, driven by the development of solar and mostly small hydroelectric power sources, as well as different types of biomass. In addition, the system will include the replacement of thermoelectric plants powered by diesel and fuel oil by natural gas plants. The prospects for Brazil's official energy plan for 2027 are aligned with the reference technology scenario, which represents the business as usual scenario. Despite this, low-carbon technologies could be implemented far beyond the NDC's goals, given the abundance of renewable natural resources in the country. • Prospects for low-carbon technologies in Brazil are lacking. • RenovaBio Law may promote bioelectricity production from sugarcane bagasse. • Small hydro will play an important role in the achievement of Brazilian NDC for the hydroelectric sector. • Wind power is developing rapidly, but still substantial room for growth. • Solar power is developing slower than expected. [ABSTRACT FROM AUTHOR]

Quantifying the economic risk associated with a solar power project is essential in order to secure financing. Quantitative risk assessment is often conducted by rerunning a model to calculate economic viability measures, including Internal Rate of Return (IRR) and Levelized Cost of Electricity (LCOE), for ranges of values of uncertain input parameters that determine capital cost, operating cost, energy yield and revenue. This paper provides an analytical approach that avoids this repetitive recalculation. The analytical approach is based on differentiating the economic viability measures with respect to the input parameters of interest. Using 20% changes in parameter values, the analytical approach is shown to agree within 0.875% for a behind-the-meter project. For an off-grid utility scale project the analytical approach is exact for five cost and energy yield parameters and agrees within 0.01% for degradation rate and 0.14% for discount rate. Moreover, the analytical approach is extended to provide differential importance measures that indicate which parameters are contributing most/least to the riskiness of the project. Results indicate that the ranking of parameters is identical for IRR and LCOE despite these being very different measures of economic viability, thus further supporting the analytical method provided in this paper. • Quantitative risk analysis is required to attract investment for solar power. • Models are often re-run over a range of uncertain input values to assess risk. • This paper derives a novel analytical approach that avoids re-running models. • The analytical approach is accurate to within 1% for a behind-the-meter project. • The analytical approach is accurate to within 0.1% for an off-grid project. [ABSTRACT FROM AUTHOR]

In the last four decades, greater attention has been paid to PV/T systems due to their advantages compared with PV or solar thermal systems alone. This paper aims to study various aspects of PV/T systems through the existing literature in order to highlight key points as future work in this field as well as illustrate different techniques used for such systems. In addition, PV/T systems are reviewed in terms of thermal and electrical side views. Furthermore, the analysis of solar thermal systems, various system applications such as air, water, air/water, phase change material PCM and Nanofluid systems are summarized. In light of most attempts to improve the PV/T system, more focus has been paid to the thermal rather than the electrical side. Furthermore, comparisons between PV/T systems in terms of performance parameters and efficiencies are presented. A critical review of many findings of previously conducted research is also discussed. It is found that the PV/T air heater system is promising for future preheating air applications. Moreover, it is suggested that the use of nanoparticles and water as base fluid improves the overall system efficiency. Furthermore, the PV side views require more attention in technical and cost terms. However, more research is essential to reduce the cost and, improve the effectiveness and technical design of such systems. [ABSTRACT FROM AUTHOR]

Solar energy potential analysis on oriented and tilted surfaces, such as building façades, is of capital importance to estimate the energy production potential in integrated systems, such as BIPVs. The spatial distribution of solar diffuse energy outstands as one of the most critical factors in order to improve performance simulations. Nevertheless, most wide spread models have been only evaluated on equator facing tilted surfaces and with daily mean or hourly mean time ranges. Thus, in this paper, 30 transposition solar diffuse irradiance models, from the semiphysical classical ones to the newest non-parametric models, are reviewed, classified according to their characteristics and evaluated against empirical 10-min averaged diffuse irradiance values gathered from high precision pyranometers placed on vertical positions facing the four cardinal directions. Models’ performance is evaluated by several statistical estimators and a benchmark has been carried out by a non-parametrical aggregating procedure. Results show that the most accurate models appear to be the non-parametric ones. From these, The Multi-Layer Perceptron obtains the best results. From the parametric models, the one whose estimations are closest to the measures is the Perez et al. with local optimized coefficients. Perez et al. model with the original coefficients, Skartveit and Olseth and Igawa et al. models also show a good performance. [ABSTRACT FROM AUTHOR]

Given the exponential cost decline trend of solar energy generation technologies, and the targeted tax incentives and loan guarantees for renewable energy in the American Recovery and Reinvestment Act of 2009, and other policy measures, solar energy generation has been enjoying rapid growth in the United States. This paper examines the incorporation of solar renewable energy into generation portfolios, and the effects of natural capital – specifically the geospatially calculated potential solar energy generation as measured by potential average annual kilowatt-hours per square meter per day − and respective state mandated “renewable portfolio standard” targets on utility-scale solar energy generation. Findings suggest that a state's natural solar energy potential is a predictor of solar energy generation development, and further this relationship is significantly moderated by state-specific renewable energy portfolio standard targets. [ABSTRACT FROM AUTHOR]

Mainstream economists have used various growth models to predict the interaction between sustainable economic growth and the endless accumulation of capital while environmental concerns and their negative externalities are left out, in most cases. In this paper, I present a structural economic model that explicitly allows for the interaction between an economy and an ecosystem. The proposed model indicates that—given a wide range of development and socio-economic infrastructure—while population growth might be a reason for the constant growth trajectory, it has an adverse effect due to the constraints of resources and the environment. This is because economic activities and population growth increase ecological disordering as they downgrade the environment, while the later element has a negative impact on living standards. The collected data focusing on different economic components show that the growth rate of GDP per capita may fall below zero as the population grows with the rate of capital accumulation and environmental depletion. Finally, considering different scenarios of utilizing solar energy for economic growth, a feasible endurance factor for sustainable development might promote the methods of using the substituted energy, focusing on solar energy. This, however, cannot be accomplished given the current speed and direction of technological progress and energy utilization. [ABSTRACT FROM AUTHOR]

Through the years using renewable energies become one of the interesting issues in each country. Among the renewable energies, solar energy is more attractive. Governments planned to install more solar power plants. Feasibility study is an important step of every solar energy project. This paper investigates the feasibility of using solar energy in different regions of South Korea. For this purpose, the maximum, minimum, and average values of yearly horizontal radiation were calculated for 24 stations for a five-year period. Monthly and annual clearness indices for these stations were then calculated. The annual average horizontal radiation map and Geographic Information Systems (GIS) maps of global horizontal radiation were prepared for each month of the year. Maps were then prepared for the annual average of monthly mean clearness index for the 24 stations. Furthermore, the sunshine hours were presented for 78 stations for a three-year period. The results show that the central and southern regions of South Korea receive higher quantities of horizontal radiation, but not the northern areas. [ABSTRACT FROM AUTHOR]

Despite about five decades of development, commercial solar energy has not yet unable to penetrate the electric and gas options. For this particular reason, designing compound parabolic concentrators-photovoltaic thermal solar collectors (CPC-PVT) continues until achieving similar or greater performance with a comparative cost. This paper outlines the various types of CPC-PV systems concerning design advantages and limitations. The article includes comparisons on used materials, optical tolerance and efficiency, and the range of the acceptance angle. The review focuses on the historical developments regarding the use of Fresnel lens for optimizing captured sunlight, 2- and 3-D CPC, parabolic trough, and materials used for coating. It is hoped that this review helps researchers to highlight the successful trends of designing CPC by sorting out the many layers and factors that are decisive in designing CPCs. It can be seen clearly the vast opportunities for developing better designs and utilizing the qualities of the material used for reflectance and absorbance. Flat plate collectors have shown an increasing drawback to deal with temperatures of more than 100 °C . The fixed orientation of CPC has a ydisadvantage due to the limitations of capturing sunlight; however, tracking mechanism could be employed to enhance the amount of the captured sunlight. The non-imaging system is also highlighted to show its efficiency over the imaging systems concerning larger accept angles, higher concentration ratios with less volume and shorter focal length, higher optical efficiency. However, for applications such as solar-to-electric conversion, imaging, and non-imaging Fresnel lens have shown almost same conversion factor. Throughout CPC designing, particular issues have to be considered such as the ratio of reflector-to-aperture size, the formation of hot spots, and the minimising of losing of multiple reflections concentrating photovoltaic (CPV) systems are still developing where new methods, designs, and materials are still being created in order to reach a low levelled cost of energy comparable to standard silicon-based PV systems. It is very important to note that non-imaging Fresnel lenses could bring a breakthrough in commercial solar energy concentration application technology very soon. [ABSTRACT FROM AUTHOR]

Solar energy plays a crucial and high-priority role in protecting and maintaining our future environment. One of the most important and outstanding factor in building a power plant is how to choose the appropriate and suitable site for solar power plants. The purpose of this research is to investigate the most felicitous locations in order to establish the photovoltaic power stations in Iran.it is highly recommended to closely consider the economical and geographical conditions. The required data were mostly obtained from satellite images and ground measurements. The principle in this paper forms some effective factors made up of in site selection and developed some guidelines about how to divide them into four categories including the value of solar radiation on earth's surface, the economic features, the technical factors and geographical considerations. It is extremely necessary to recognize the need to closely examine an important issue that these factors were analyzed and weighted by Analytical Hierarchy Process (AHP) and then the potential map was extracted. An understanding and appreciation of results represent appropriate locations namely Fars and Sistan and Baluchistan provinces which have higher potential to build Photovoltaic power plants. Ultimately, through research, it has been developed a model and map with maximum efficiency for gaining a deeper understanding of the most suitable location for the fixed panel power plant which was obtained. [ABSTRACT FROM AUTHOR]

Deployments of renewable energy technologies in the current century represent a critical approach to sustainable development. Renewable energy can be generated from sources with the backdrop to restock themselves based on timescale. The most important sources of renewable energy include solar photovoltaic conversion technologies, biomass and biofuel energy systems, wind energy turbines, geothermal energy technologies and hydroelectric power systems. Considerable investment in renewable energy in a country can lower the nation's dependency on imported fuels and purchase of energy from foreign market. It also drives technological innovation and generate employment scheme while enhancing clean development mechanism. Consequently, this paper presents the existing renewable energy technologies in the Nigeria and as well makes some critical recommendations to further induce development of renewable and sustainable energy systems based on autonomous energy systems and microgrid (µgrid) technologies. The recommendations are made based on varieties of energy technologies for solar power generation, biomass and bioenergy, wind energy, hydropower generation and the combined generation systems using hybrid energy mechanism. The structure of the study is concluded based on suggestions on how to pursue some impending socio-political, technological, investment policy and legislative issues for effective renewable energy development in the country. [ABSTRACT FROM AUTHOR]

This paper endeavors to provide the reader with an overview of the various tools needed to forecast photovoltaic (PV) power within a very short-term horizon. The study focuses on the specific application of a large scale grid-connected PV farm. Solar resource is largely underexploited worldwide whereas it exceeds by far humans’ energy needs. In the current context of global warming, PV energy could potentially play a major role to substitute fossil fuels within the main grid in the future. Indeed, the number of utility-scale PV farms is currently fast increasing globally, with planned capacities in excess of several hundred megawatts. This makes the cost of PV-generated electricity quickly plummet and reach parity with non-renewable resources. However, like many other renewable energy sources, PV power depends highly on weather conditions. This particularity makes PV energy difficult to dispatch unless a properly sized and controlled energy storage system (ESU) is used. An accurate power forecasting method is then required to ensure power continuity but also to manage the ramp rates of the overall power system. In order to perform these actions, the forecasting timeframe also called horizon must be first defined according to the grid operation that is considered. This leads to define both spatial and temporal resolutions. As a second step, an adequate source of input data must be selected. As a third step, the input data must be processed with statistical methods. Finally, the processed data are fed to a precise PV model. It is found that forecasting the irradiance and the cell temperature are the best approaches to forecast precisely swift PV power fluctuations due to the cloud cover. A combination of several sources of input data like satellite and land-based sky imaging also lead to the best results for very-short term forecasting. [ABSTRACT FROM AUTHOR]

This paper reports a review of various methods of solar tracking with gains in energy due to tracking and different MPPT algorithms. The fossil fuels are non-renewable, limited and deplete. Therefore, it is imperative to find alternative sources of energy. As solar energy is available abundantly in nature, it can be considered as a best alternative to meet the energy demand. It is sustainable, renewable and scalable. Increasing the efficiency of harnessing solar energy should be one of our foremost concerns as it is a renewable source. The challenge in tapping this energy is to increase the efficiency as well as to reduce the cost of production. Therefore an attempt is made to review the various Maximum Power Point Tracking (MPPT) algorithms, different solar tracking methods and the energy gained by using these methods. Further, a single axis microcontroller based automatic tracker is implemented and tested for its performance in real time. The work focusses on the orientation of solar panel towards the direction of maximum radiation by using a stepper motor interfaced with ARM processor. [ABSTRACT FROM AUTHOR]

According to energy policies, it is necessary to replace electrical energy or fossil fuels by renewable energy sources. Solar energy systems are recognized as one of these sources. In such systems, high-performance is one of the essential needs. Porous materials have been introduced as one of the most efficient and affordable techniques to improve the heat transfer and energy efficiency in solar energy systems. In this review, the applications of porous materials and their advantages and limitations on different types of solar energy systems are summarized. Moreover, the structures of each system with their applications are briefly introduced. Solar energy systems covered in this paper contains both energy conversion and energy storage systems. [ABSTRACT FROM AUTHOR]

This paper presents and analyzes Qatar's long-term solar resource potential to assess the power generation prospects of diverse solar plants in the country. Solar resource potential is obtained by applying kriging techniques to satellite-derived data to produce maps of monthly and yearly averages of global horizontal and direct normal irradiation. This analysis is based on eleven years of hourly satellite-derived solar radiation data calculated through a modified version of the Heliosat-3 model, where the satellite estimations have been improved and adapted to site using bias removal methods through a comparison with ground radiometric measurements. Solar resource data are then used in combination with local meteorological data as input to the System Advisor Model (SAM) in TMY3 format to simulate the solar plant operational prospects of various concentrating solar systems (CSP) and photovoltaic (PV) reference plants over eleven years. The ensuing simulation results show that parabolic troughs, molten salt tower plant with large thermal storage systems, and large grid-connected PV systems offer the best solutions in terms of interannual variability and long-term stability of the electricity produced. [ABSTRACT FROM AUTHOR]

According to the Vision 2023 agenda, the Turkish government plans to produce 30% of Turkey's electricity demand from renewable energy sources in 2023. This means hydroelectric, wind and solar energy capacities would increase to 36,000 MW, 20,000 MW and 3000 MW, respectively. Increased hydroelectric capacity would indeed benefit stability and flexibility of the existing energy infrastructure. However, increased wind and solar capacity could bring intermittency problems due to nature of these energy sources. Recently, pumped hydroelectric energy storage (PHES) has become a hot topic in Turkey. And, its potential applications via synergistic utilisation with wind and solar energy to solve the aforementioned intermittency problems is being discussed. Yet, detailed information in the literature about PHES in Turkey is scarce. Therefore, this paper was intended to provide this crucial information. Detailed analysis showed even if all obstacles are overcome and all potential PHES capacity is used PHES could only provide a storage capacity worth equivalent to 0.6-0.8% of Turkey's annual electricity demand in 2023. It is estimated that the overnight capital cost required to develop this PHES potential is between 3.6 and 6.5 billion US$. Even so, there would be serious economic risks of PHES plants. Because, PHES systems are currently net consumers of energy. Current study also showed that instead of focusing on PHES, flexibility of Turkish electricity market could be sustained by diversifying energy sources and increasing nuclear energy capacity. It is estimated that an additional 490 MW of nuclear capacity could provide the same potential PHES capacity. By this way, intermittency problems associated with increased share of solar and wind energy can be easily tackled without imperilling the Vision 2023 energy targets. [ABSTRACT FROM AUTHOR]

This paper surveys economic assessments of concentrated solar power (CSP) technologies and finds two dominant assessment methods. A majority of studies reported in the literature are based on the levelized cost of electricity (LCOE), while a small subset of studies consider time-varying meteorological and electricity market conditions. Several studies argue that LCOE undervalues dynamic flexibility provided by thermal energy storage and does not consider revenue opportunities provided by electricity markets at different time scales. As a result, some studies find that both LCOE and revenue can in fact be conflicting metrics for certain designs and market conditions. This review finds strong variations in LCOE and revenue estimates in the literature. As comparisons between CSP and other generation technologies (e.g., fossil, wind, and photovoltaic) are dictated by the chosen economic metric, it is imperative that policy and investment decisions should carefully consider time-varying effects and flexibility. Finally, research directions are proposed to increasing the fidelity of economic assessments and to mitigate discrepancies. [ABSTRACT FROM AUTHOR]

This paper debates the main reasons why Chinese and Brazilian energy policies have not focused on Concentrating Solar Power (CSP) deployment until now. Like most emerging economies, China and Brazil have registered large increases in energy demand, as well as considerable growth of energy-related greenhouse gas (GHG) emissions. On the other hand, both countries have played an important role on the expansion of renewable energy infrastructure and - considering that large portions of their territories present high levels of "Direct Normal Irradiation" (DNI) - CSP technologies might have figured as an important strategy for the mitigation of atmosphere pollution and global warming. Since large scale deployment of CSP technologies still implies high "Levelized Costs Of Electricity" (LCOE) that could affect the competitiveness of national industry in global markets, we argue that a comprehensive answer for this question must place national energy policies in the context of a "world-system" analysis. CSP has not benefited from the international demand that has boosted wind turbines and photovoltaic cells with their subsequent price reductions. Furthermore, we will discuss the "elective affinities" between thermal solar investments and the development of those regions that present the lowest performances in the Chinese and Brazilian socioeconomic realities. [ABSTRACT FROM AUTHOR]

As part of EU incentives, the UK government have set ambitious environmental targets relating to energy consumption including a reduction of carbon emissions of 80% by 2050. The use of various technologies can help meet these targets as well as providing a secure energy source for the UK in the future. This research took the UK as a case study and investigated where reduction measures are most suited to reduce energy consumption. This paper presents a review on the current state-of-the-art on the domestic technology available, in particular solar energy, heat pumps, phase changing materials (PCMs) and micro combined heat and power (micro-CHP) systems, aiming at identifying research and development opportunities for energy saving in these fields. Furthermore, the financial as well as environmental aspects are assessed as these are the two key considerations of typical household. A typical UK house design, including the floor plan, is created through the use of computer aided design (CAD) software. The house design gives a payback period between 8.7 years at best and 11.6 years at worst. [ABSTRACT FROM AUTHOR]

The current study concerns the fundamental problems of Legionnaires disease. Four decades after Legionnaires' bacteria was first identified there is still a low level of clinical awareness. Humans are infected by inhalation of aerosolized water and/or soil contaminated with the bacteria. Several control methods are available for water disinfection: biocide, ultraviolet light sterilization, copper-silver ionization, ozonation etc. but only thermal treatment can completely eliminate Legionella , which is killed almost instantly at 70 °C. The current paper describes Legionella disinfection by a solar concentrator combined with a heat recovery system that reduces the heat demand. Though this study is made for a small system (160 l of hot water per day) the system can be enlarged (more hot water and more solar collector area) and the results are thus valid also for such larger systems. Here experiments of water treatment by a solar concentrator are summarized and analyzed where the temperature exceeds 80 °C at the outlet of the heat exchanger. [ABSTRACT FROM AUTHOR]

Equality between economic progress and environmental sustainability is essential for a developing country like India. In the present time, the economy of India is growing rapidly in a vibrant mode and an efficient way, which in turn demands huge uninterrupted energy supplies. The country's energy needs are met mostly by the usage of fossil fuels and nearly 70% of electricity is generated from coal based power plants. In India, nearly 840 million people depend on traditional biomass to satisfy their energy necessities. Approximately 74 million rural people do not have access to modern lighting systems and around 81 million households do not have access to electricity, which is a major challenge to India's energy security. In order to achieve stable sustainable energy in the long-run, significant progress in renewable energy sectors is needed. Favorably, due to India's geographic location, the country is blessed with abundant renewable energy resources, which has not yet been exploited completely. So the central and state governments of the country have framed various policies and are providing subsidies to encourage the utilization of solar photovoltaic systems. In this paper, a comprehensive review of the potential, current developmental status and prospects of solar energy of India is briefed. The various applications of solar energy such as water heaters, desalination units, pasteurizers, food drying units, water purifier, space heating systems, air-conditioning units, cookers, water pumps, aerators, solar-wind hybrid systems and grid connected photovoltaic systems are explained. The study also mentions the current renewable energy policies, the barriers blocking the progress of the solar manufacturing units and some possible future recommendations that might speed up renewable energy developments in India. [ABSTRACT FROM AUTHOR]

In this paper, the potential of solar and wind energy-based distributed generation (DG) in Saudi Arabia is simultaneously analyzed with the aim of maximizing the utilization of available resources. It begins with an analysis of DG application potential for wind and solar energy resources in various regions of Saudi Arabia. The progress of DG applications in terms of research, planning, and exploitation of wind and solar energy resources is then presented. An assessment of the DG contribution to the energy sector of Saudi Arabia has been conducted and the barriers and challenges for the implementation of DG systems in the country are discussed with suggested measures to overcome the challenges. The main findings are that with the huge potential of wind and solar resources for DG applications the country has targeted 50 GW of wind and solar capacity by the year 2040. The Saudi government is expected to provide full support in the form of financial incentives for solar and wind energy projects in order to boost renewable energy development. [ABSTRACT FROM AUTHOR]

Hydrogen is one of the most important energy sources of the future; as well, it is the least harmful form of energy for the environment. Hydrogen is a clean and renewable energy supply and be used as non-toxic energy storage and transport medium. During electrolysis of water, a high power dissipation value is the most important problem of such systems. Several internal and external variables have an influence on both of electrical behavior of electrolysis cells and their efficiency namely: nature, concentration and purity of the electrolyte, electrodes type and their form, cell temperature and pressure…etc. This paper presents an experimental study regarding hydrogen production by water's electrolysis using a photovoltaic panel current. The study consists of seeing the effect of the electrolyte nature on the volume of hydrogen produced. The experiments conducted at Ouargla University which including a comparison between two alkaline electrolytes behaviors, show that potassium hydroxide (KOH 3 M) is more effective than sodium hydroxide (NaOH 3 M) for the same electrolysis conditions of pressure, temperature, load current and load voltage. Overall production of KOH and NaOH cells is 5122 cm 3 and 3279 cm 3 of hydrogen at standard conditions with recording maximum efficiencies of 90.25% and 83.33% respectively. [ABSTRACT FROM AUTHOR]

Preservation of the environment has become the main motivation to integrate more renewable energy sources (RESs) in electrical networks. However, several technical issues are prevalent at high level RES penetration. The most important technical issue is the difficulty in achieving the frequency stability of these new systems, as they contain less generation units that provide reserve power. Moreover, new power systems have small inertia constant due to the decoupling of the RESs from the AC grid using power converters. Therefore, the RESs in normal operation cannot participate with other conventional generation sources in frequency regulation. This paper reviews several inertia and frequency control techniques proposed for variable speed wind turbines and solar PV generators. Generally, the inertia and frequency regulation techniques were divided into two main groups. The first group includes the deloading technique, which allow the RESs to keep a certain amount of reserve power, while the second group includes inertia emulation, fast power reserve, and droop techniques, which is used to release the RESs reserve power at under frequency events. [ABSTRACT FROM AUTHOR]

The solar water heating system (SWHS) is one of the most common application of solar energy utilization system. The usage of solar water heating system is not commonly employed throughout the globe, due to its high initial cost. The advancement in SWHS will lead to be beneficial over conventional system over the long span of time. The eco-friendly nature of such system promotes these systems to be used frequently in both domestic and industrial heating. The investigators throughout the globe focusing on technical advancement as well as economic feasibility of SWHS. The present study focused on to report such studies, which demonstrates the economic feasibility of SWHS in the long run. The payback period of SWHS varies from one origin to other as it depends on numerous factors like price of fossil fuels, rate of subsidy, solar insolation etc. Initially the paper reported the basic components of SWHS, and their advancements, further the global scenario of SWHS is discussed, followed by the studies reported on a techno economic analysis of SWHS, which shows that the economic feasibility is equally important as technical feasibility for its implementation. The last section inculcates the recent studies on the technical advancement of SWHS and the future research trends of SWHS were discussed. [ABSTRACT FROM AUTHOR]

Photovoltaic water pumping system (PVPS) is an important and promising application of solar energy systems especially in remote areas. In this review paper, research work on PVPS modeling, reliability, feasibility, field performance, design procedures and control strategies is analyzed and reported. In addition, technical challenges to this science are concluded in this review. According to the results, the numerical method is recommended for sizing PVPS. In the meanwhile, incremental conductance and artificial intelligent (AI) based maximum power point tracking algorithms are the most recommended control strategies for PVPS. On the other hand, According to reported PVPS performance, the average overall system's efficiency is about 3.4% with average annual productivity rate of 6580.611 m 3 /kWp. In general PVPS have a number of challenges related to design procedure, modeling method, control strategy, availability of data and site obstacles such as shadow effects. [ABSTRACT FROM AUTHOR]