Showing papers on "Photovoltaic thermal hybrid solar collector published in 2015"

Types of Solar Cells and Application

Abstract: A solar cell is an electronic device which directly converts sunlight into electricity. Light shining on the solar cell produces both a current and a voltage to generate electric power. This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state, and secondly, the movement of this higher energy electron from the solar cell into an external circuit. The electron then dissipates its energy in the external circuit and returns to the solar cell. A variety of materials and processes can potentially satisfy the requirements for photovoltaic energy conversion, but in practice nearly all photovoltaic energy conversion uses semiconductor materials in the form of a p-n junction. With regard to the development of sustainable energy, such as solar energy, in this article we will Study types of solar cells and their applications

A review on the applications of nanofluids in solar energy systems

Abstract: The negative impact of human activities on the environment receives tremendous attention, especially on the increased global temperature. To combat climate change, clean and sustainable energy sources need to be rapidly developed. Solar energy technology is considered as one of the ideal candidates, which directly converts solar energy into electricity and heat without any greenhouse gas emissions. In both areas, high-performance cooling, heating and electricity generation is one of the vital needs. Modern nanotechnology can produce metallic or nonmetallic particles of nanometer dimensions which have unique mechanical, optical, electrical, magnetic, and thermal properties. Studies in this field indicate that exploiting nanofluid in solar systems, offers unique advantages over conventional fluids. In this paper, the applications of nanofluids on different types of solar collectors, photovoltaic systems and solar thermoelectrics are reviewed. Beside the wide range of energy conversion, the efforts done on the energy storage system (ESS) have been reviewed. In the field of economics, nanotech reduces manufacturing costs as a result of using a low temperature process.

Solar Cells: In Research and Applications—A Review

Abstract: The light from the Sun is a non-vanishing renewable source of energy which is free from environmental pollution and noise. It can easily compensate the energy drawn from the non-renewable sources of energy such as fossil fuels and petroleum deposits inside the earth. The fabrication of solar cells has passed through a large number of improvement steps from one generation to another. Silicon based solar cells were the first generation solar cells grown on Si wafers, mainly single crystals. Further development to thin films, dye sensitized solar cells and organic solar cells enhanced the cell efficiency. The development is basically hindered by the cost and efficiency. In order to choose the right solar cell for a specific geographic location, we are required to understand fundamental mechanisms and functions of several solar technologies that are widely studied. In this article, we have reviewed a progressive development in the solar cell research from one generation to other, and discussed about their future trends and aspects. The article also tries to emphasize the various practices and methods to promote the benefits of solar energy.

Flat plate solar photovoltaic–thermal (PV/T) systems : A reference guide

Abstract: The increasing installed area of solar technologies around the world gives us an idea about the unlimited potential available in solar energy. This combined with the rising fossil fuel prices and frequent power outages, favor decentralized power generation among domestic consumers and small industries. However, the low energy of the solar PV module, the low exergy of the solar flat plate thermal collector and limited usable shadow-free space on building roof-tops could be overcome by the high overall (electrical and thermal) efficiency of a solar Photovoltaic Thermal (PV/T) system, which combines the electrical and thermal components in a single unit area. This paper gives a brief overview of the different solar flat plate PV/T technologies, their efficiencies, applications, advantages, limitations and research opportunities available.

Advancements in hybrid photovoltaic systems for enhanced solar cells performance

Abstract: Photovoltaic (PV) cells can absorb up to 80% of the incident solar radiation available in the solar spectrum, however, only a certain percentage of the absorbed incident energy is converted into electricity depending on the conversion efficiency of the PV cell technology. The remainder of the energy is dissipated as heat accumulating on the surface of the cells causing elevated temperatures. Temperature rise of PV cells is considered as one of the most critical issues influencing their performance, causing serious degradation and shortening the life-time of the cells. Hence cooling of PV modules during operation is essential and must be an integral part of PV systems particularly in sun-drenched locations. Many researches have been conducted investigating a range of methods that can be employed to provide thermal management for PV systems. Among these designs, systems utilizing air, liquid, heat pipes, phase change materials (PCMs), and thermoelectric (TE) devices to aid cooling of PV cells. This paper provides a comprehensive review of various methods reported in the literature and discusses various design and operating parameters influencing the cooling capacity for PV systems leading to an enhanced performance.

Phase change materials for photovoltaic thermal management

Abstract: This comprehensive review discusses methods that have been used for the thermal management of photovoltaic modules. Particular attention has been paid to the use of phase change material (PCM) in the heat management of photovoltaic (PV), concentrating photovoltaic (CPV) and building integrated photovoltaic (BIPV) systems. Regulating the temperature of PV systems comprised of crystalline silicon cells appears to be the most economically viable for the use of PV/PCM systems, as increases in temperature have the most detrimental effect on the efficiency of silicon solar cells compared to organic or thin film cells. Studies have shown that the use of PCM helps to improve the performance of PV although there is still more to be explored and improved particularly the solidification and discharge of PCM.

A thermodynamic review of solar air heaters

Abstract: Solar air heaters (SAHs) form the foremost component of solar energy utilization system. These air heaters absorb the irradiance and convert it into thermal energy at the absorbing surface and then transfer this energy to a fluid flowing through the collector. SAHs are inexpensive and most used collection devices because of their inherent simplicity. SAHs are found in several solar energy applications, especially for space heating, timber seasoning and agriculture drying. It has been observed by studying the previous literature that all the elements of a solar air heater such as; an absorber tray, the ducts, glazing, insulation, extended surfaces, as well as the tilt angle, have a significant effect on the thermal performance of the system. This review article focus on the developments that has followed round the globe in various aspects of solar air heating systems since 1877 up to now, with a glimpse of some novel patents of SAHs. The various methods that are used to improve the thermal performance of SAHs such as; optimizing the dimensions of the air heater construction elements, use of extended surfaces with different shapes and dimensions, use of sensible or latent storage media, use of concentrators to augment the available solar radiation, integrating photovoltaic elements with the heaters, etc, are also reported. Besides this, some benefits by using the SAHs has been discussed.

Concentrated photovoltaic thermal (CPVT) solar collector systems: Part I – Fundamentals, design considerations and current technologies

Abstract: Concentrated photovoltaic thermal (CPVT) solar collectors have been gaining ever-increasing attention from the scientific community and industrial developers due to their promising potential to pave the way for the penetration of solar energy into modern day power generation technologies. CPVTs׳ flexibility, manufacturability, high efficiency, and multi-output nature inspired many innovative designs and design improvements available in the literature. In this study, a comprehensive, up-to-date review of the governing scientific basics, system variations, and technological advances in CPVT systems will be presented. The study is split into two parts. The first part covers CPVTs׳ characteristics and design considerations in addition to a review of the principals and technological advances in the solar components that compose a CPVT (i.e., photovoltaic cells, solar thermal collectors, concentrator optics, tracking mechanisms, concentrated photovoltaics, and concentrated solar thermal systems). While the second part thoroughly covers CPVTs׳ published studies, application areas, performance assessment, commercial initiatives, and research prospects.

A Hybridized Power Panel to Simultaneously Generate Electricity from Sunlight, Raindrops, and Wind around the Clock

Abstract: With the solar panels quickly spreading across the rooftops worldwide, solar power is now very popular. However, the output of the solar cell panels is highly dependent on weather conditions, making it rather unstable. Here, a hybridized power panel that can simultaneously generate power from sunlight, raindrop, and wind is proposed and demonstrated, when any or all of them are available in ambient environment. Without compromising the output performance and conversion efficiency of the solar cell itself, the presented hybrid cell can deliver an average output of 86 mW m−2 from the water drops at a dripping rate of 13.6 mL s−1, and an average output of 8 mW m−2 from wind at a speed of 2.7 m s−1, which is an innovative energy compensation to the common solar cells, especially in rainy seasons or at night. Given the compelling features, such as cost-effectiveness and a greatly expanded working time, the reported hybrid cell renders an innovative way to realize multiple kinds of energy harvesting and as an useful compensation to the currently widely used solar cells. The demonstrated concept here will possibly be adopted in a variety of circumstances and change the traditional way of solar energy harvesting.

Historical and recent development of photovoltaic thermal (PVT) technologies

Abstract: In the context of climate change in the world at the global level, various actions are taken for the development of renewable Energy and particularly solar energy which have potential for future energy applications. The current popular technology converts solar energy into electricity and heat separately. The photovoltaic thermal (PVT) system is designed to generate thermal and electrical energy simultaneously. A major research and development work on the photovoltaic thermal (PVT) hybrid technology has been done since last 30 years. Different types of solar thermal collector and new materials for PV cells have been developed for efficient solar energy utilization. The photovoltaic (PV) cells suffer efficiency drop as their operating temperature increases especially under high insolation levels. The overall electrical efficiency of the photovoltaic (PV) module can be increased by reducing the temperature of the PV module by withdrawing the thermal energy associated with the PV module. Both water and air either by forced or natural flow has been used for PV cooling through a thermal unit attached to the back of the module yielding photovoltaic thermal (PVT) collector. The main purpose of heat extraction unit is to extract heat from the photovoltaic system and keep its temperature at satisfactory level so that it can work efficiently. Till date many researchers have done a lot of work and number of studies have been carried out in designing, simulation, modeling, and testing of these systems. This paper reviews on the state and development of PVT technology around the world but the studies includes experimental and analytical are mainly focused on photovoltaic thermal technologies at the Indian subcontinent.

Input Parameters for the Simulation of Silicon Solar Cells in 2014

Abstract: Within the silicon photovoltaics (PV) community, there are many approaches, tools, and input parameters for simulating solar cells, making it difficult for newcomers to establish a complete and representative starting point and imposing high requirements on experts to tediously state all assumptions and inputs for replication In this review, we address these problems by providing complete and representative input parameter sets to simulate six major types of crystalline silicon solar cells Where possible, the inputs are justified and up-to-date for the respective cell types, and they produce representative measurable cell characteristics Details of the modeling approaches that can replicate the simulations are presented as well The input parameters listed here provide a sensible and consistent reference point for researchers on which to base their refinements and extensions

Phase change materials for solar thermal energy storage in residential buildings in cold climate

Abstract: Heating accounts for a large proportion of energy consumption in residential buildings located in cold climate. Solar energy plays an important role in responding to the growing demand of energy as well as dealing with pressing climate change and air pollution issues. Solar energy is featured with low-density and intermittency, therefore an appropriate storage method is required. This paper reports a critical review of existing studies on thermal storage systems that employ various methods. Latent heat storage using phase change materials (PCMs) is one of the most effective methods to store thermal energy, and it can significantly reduce area for solar collector. During the application of PCM, the solid–liquid phase change can be used to store a large quantity of energy where the selection of the PCM is most critical. A numerical study is presented in this study to explore the effectiveness of NH 4 Al(SO 4 ) 2 ·12H 2 O as a new inorganic phase change material (PCM). Its characteristics and heat transfer patterns were studied by means of both experiment and simulation. The results show that heat absorption and storage are more efficient when temperature of heat source is 26.5 °C greater than the phase transition temperature. According to heat transfer characteristics at both radial and axial directions, it is suggested to set up some small exchangers so that solar energy can be stored unit by unit in practice. Such system is more effective in low density residential buildings.

Experimental investigation of CuO nanofluid-based Direct Absorption Solar Collector for residential applications

Abstract: Solar water heating systems are the most economical and large scale application of solar energy in residential buildings. In order to enhance the efficiency of these systems, Direct Absorption Solar Collector (DASC) which used nanofluids with appropriate optical and heat transfer properties as absorbing medium, has been recently proposed. In this study, a prototype of this new type of collector was built with applicability for domestic solar water heater. Different volume fractions of copper oxide nanoparticles in water and ethylene glycol mixture (70%:30% in volume) as the base fluid were prepared and their thermo-physical and optical properties were presented. The procedure of EN 12975-2 standard was used for testing the thermal performance of the collector. The tests were performed in different flowrates from 54 to 90 l/h (0.015–0.025 kg/s) and two different internal surfaces (black and reflective) of bottom wall. The efficiency of the collector with black internal surface is about 11.4% more than that of with reflective internal surface using the base fluid at 90 l/h flowrate. The collector efficiency is increased by increasing nanofluid volume fraction and flowrates. The nanofluids improved the collector efficiency by 9–17% than the base fluid. Based on the results, the performance of this new kind of collector as the main part of solar water heater appears promising, leading to considerably higher efficiencies.

A review of thermal energy storage technologies and control approaches for solar cooling

Abstract: This paper presents a review of thermal storage media and system design options suitable for solar cooling applications. The review covers solar cooling applications with heat input in the range of 60–250 °C. Special attention is given to high temperature (>100 °C) high efficiency cooling applications that have been largely ignored in existing reviews. Sensible and latent heat storage materials have been tabulated according to their suitability for double effect and triple effect chillers. A summary of system designs for water storage (sensible heat), and phase change material storage (latent heat) has been provided. The article summarizes literature related to solar thermal air-conditioning systems from a material level as well as plant level considerations. This includes evaluating various control strategies for managing the thermal store, that aid in optimal functioning of a solar air conditioning plant. Modeling approaches are reviewed for sizing the solar thermal store, highlighting the large difference seen in specific storage size when applied in different applications.

Dynamic Energy Management of Hybrid Energy Storage System With High-Gain PV Converter

Abstract: In this paper, fast acting dc-link voltage-based energy management schemes are proposed for a hybrid energy storage system fed by solar photovoltaic (PV) energy. Using the proposed control schemes, quick fluctuations of load are supplied by the supercapacitors and the average load demand is controlled by the batteries. Fast dc-link voltage, effective energy management, and reduced current stress on battery are the main features achieved from the proposed control schemes. The effectiveness of the proposed control schemes are compared with the unified cascaded control. Small-signal control gains are formulated to design the voltage and current loops of the proposed energy management schemes. Detailed stability analysis is also presented to find the boundary values of compensator gains. In addition, a high-gain PV converter is proposed for extraction of maximum power from the solar panels. High voltage gain, reduced reverse recovery of diodes, and less duty cycle operation are the key features obtained from the proposed high-gain converter. The validity of the proposed energy management schemes with high-gain converter is verified by the detailed simulation and experimental studies.

Understanding the Outstanding Power Conversion Efficiency of Perovskite-Based Solar Cells.

Abstract: Currently most solar cells are based on silicon and show efficiencies over 15 %. Since the production of silicon-based solar panels is expensive, alternative technologies for energy conversion have evolved in the last decades based on organic materials (OPVs; organic photovoltaics) and hybrid materials (DSSCs; dye-sensitized solar cells). OPVs and DSSCs have the prospect of cheap large-scale production but still suffer lower power conversion efficiencies (8–13%). In the commercially available silicon solar cells, when a photon from the solar spectrum is absorbed, the exciton binding energy is so small that the electron and hole can separate, and thus a current can be produced. However, in an organic material, the absorption of a photon creates a strongly bound exciton, basically a neutral electron–hole pair. This means that absorbed photons produce a neutral excitation, not free carriers, and thus a dissociation interface is required. Within organic solar cells, for example, the well-known P3HT/ PCBM heterojunction (Figure 1: Donor/Acceptor), the necessary steps to transform sunlight into electricity are: 1) absorption of sunlight and formation of the exciton; 2) exciton diffusion to the donor–acceptor interface; 3) exciton dissociation into free charges (electrons and holes), and 4) charge transport to and collection at the electrodes. In the past few years the photovoltaic field has experienced a dramatic boost due to the development of perovskitebased solar cells (PSCs). They have shown an unprecedented speed of evolution and outperform established organic and hybrid materials already after only few years of investigation. PSCs were initially introduced as type of DSSC, but subsequent studies indicated they have a unique working mechanism. Consequently, these so-called “third-generation solar cells” have been one of the hottest topics in sustainable energy science. However, since the first highly efficient devices were published, their working principle has been matter of debate. One of the first research papers dealing with this issue was written by Mora-Sero, Park et al. They observed charge