Thin Film Photovoltaic Panels Research Articles

A methodology to liberate critical metals in waste solar panel

The availability of critical metals is one of the driving factor to secure the transition of energy production to a renewable, low carbon one because of the material requirement in photovoltaic technology (PV), wind power generation and batteries. For example, precious metals are vital to manufacture crystalline silicon solar panel and tellurium, germanium, indium and gallium are essential in thin film photovoltaic panels. However, the pressure on the supply of critical metals increases with the growth of photovoltaics. Considering the resource availability, the recycling of critical metals from waste solar panels can enhance the sustainability of end-of-life management, although the recycled metal input is limited in present state. Among the recycling techniques, the separation and liberation of metals from non-metals are crucial. This study investigate a methodology to liberate thin film materials from copper indium gallium selenide (CIGS) thin-film solar panel to recycle photovoltaic material including indium and gallium via a mechanical process.An experimental technique using mineral processing techniques, crushing and grinding, are proposed to recycle critical metals from CIGS solar panel. In this study, the crushing experiments were conducted and the size based elemental distribution was analysed. The results showed crushing is capable to delaminate glass substrate and Fuerstenau upgrading curves and the ore separation degree were used to show that selective liberation occurs and the critical metals concentrate in coarse size fraction but may not be fully liberated. The morphology test using SEM-EDS to observe the surface of broken panel and the classification of broken particle based on size, metal concentration and surface morphology were conducted. The results suggested that approximately 90 w% of functional materials are still laminated on EVA in the size fraction larger greater than 2360 μm. It shows crushing alone will not fully liberate the material. Grinding can be used as a second stage recycling method, de-coating the target materials. The grinding test resulted in a more than 80 w% recovery rate of indium and the fine particle less than 38 μm contains more than 1500 ppm indium, more than 480 ppm gallium and 1500 ppm molybdenum. It could show that the combination of crushing and grinding is suitable to delaminate the panel and de-coat the critical metals to liberate and concentrate the metals.

Effect of parasitic resistances on CdTe solar cell and validation with datasheet of FS-6450A in Matlab/Simulink

Cadmium telluride (CdTe) is the second popular choice after silicon for the solar cell in photovoltaic (PV) technology. Among the thin-film photovoltaic panels, CdTe reaches its first position to surpass crystalline silicon PV in cheapness and confined a large space in the PV market. Before constructing CdTe PV panels its operating characteristics should be properly judged. Any solar cell being related to a high level of nonlinearity, the model parameter is to be chosen judiciously. The operating characteristics can be well considered after the model circuit parameter comes accurately. In this paper operating characteristics of a thin-film CdTe solar module is shown with the variation of series and shunt resistance. Also considering parasitic resistances, the output characteristics of the solar cell varying climate condition is shown. Validation with FS-6450A PV module and all the simulation works are done in Matlab/Simulink environment. In the end, it is concluded with possible outcomes.

Fingerprinting fluid evolution by trace elements in epithermal pyrite, Vatukoula Au-Te deposit, Fiji

Tellurium (Te) is an important element for green technologies, including thin film photovoltaic panels. Stagnating supply caused by its by-product dependency together with an increasing demand will likely lead to a shortage in the near future. Pyrite may represent a potential target for the direct recovery of Te, since the concentrations of Te can reach weight percent levels under specific, but poorly constrained hydrothermal conditions. The Vatukoula (formerly Emperor) epithermal Au-Te deposit is currently mined for Au and ~ 75% are recovered from Au-tellurides and pyrite. Tellurium has been processed in the past, but is now sent to tailings despite of concentrations reaching 1.4 wt. % in pyrite, which makes this system a natural laboratory to investigate key Te enrichment processes.The epithermal mineralisation at Vatukoula consists of an early low-grade disseminated host-rock and a later high-grade Ag-Au-Te vein-type stage. Pyrite occurs in both ore-types with diverse As contents including concentrations < 0.5 wt. % in pure pyrite, 0.5 to 13 wt. % in low-As and 23 to 43 wt. % in high-As pyrite, reflecting increasing fluid As with system evolution towards the high-grade mineralisation. Tellurium contents in pyrite increase from pure pyrite (up to 220 ppm) to low-As pyrite (up to 1.4 wt. %), but with a decrease towards high-As pyrite (up to 185 ppm). This is a yet unknown relation, since trace element incorporation in pyrite is usually facilitated by increasing As. Instead, the presented results suggest a threshold between 13 and 23 wt. % As, above which the incorporation of Te and related elements (e.g., Ag, Au) may be less favourable. Mineral stabilities, trace element ratios (e.g., Sb/Pb, Tl/Pb) and LA-ICP-MS mapping of texturally distinct pyrite indicate that fluid boiling was a critical process for the Ag, Au and Te enrichment in the Vatukoula epithermal system. Fluid sulphidation states decreased with proceeding evolution of the epithermal system from initially intermediate- to late low-sulphidation conditions, which led to the diverse chemical character of pyrite. Early pure pyrite primarily formed as a replacement product of magnetite in the altered host rocks, whereas low- and high-As pyrite precipitated in the direct vicinity of Ag-Au-telluride veins, from which most of the As, Ag, Te and Au hosted in pyrite was derived from. Consequently, the trace element composition of pyrite allows the fingerprinting of the fluid evolution of Te-rich ore-forming systems like Vatukoula, Fiji.

Comparative analysis of the SolWat photovoltaic performance regarding different PV technologies and hydraulic retention times

SolWat is a hybrid photovoltaic (PV) and photochemical technology, which integrating a PV module and a water disinfection reactor on top of it, was developed to meet the needs of safe drinking-water and electricity in developing countries. This paper assessed the effects of the water disinfection reactor on the electrical performance of the PV module integrated into the SolWat system regarding different hydraulic retention times (HRT) and PV technologies. With this aim, several tests were conducted outdoors under natural climatic conditions. Results showed that while no clear benefits were observed from the water disinfection reactor and reduced HRT on the electrical performance of both monocrystalline and multicrystalline technologies, the final energy output of a-Si thin film PV panels benefited from the cooling effect of water on its front surface being able to produce even more energy than a single PV panel when working at shorter HRT. In addition, the working module temperature was always lower when HRT was shorter; its efficiency under the diffuse light conditions created by the water disinfection reactor was better than monocrystalline and multicrystalline technologies; and its black surface enhanced the absorption of far infrared light and heat by the water disinfection reactor favouring higher water temperatures and thus higher disinfection rates. In conclusion, thin film PV technology is the most suitable to be integrated into the hybrid SolWat systems when comparing with monocrystalline and multicrystalline technologies.

Techno-economic performance comparison of crystalline and thin film PV panels under varying meteorological conditions: A high solar resource southern hemisphere case

Photovoltaic panel technologies have evolved considerably over a limited period. The most popular PV panel technologies can be divided into two main groups, the first being crystalline technologies and second, thin film technologies. This investigation compares the financial performance of three different photovoltaic (PV) panel technologies, namely, monocrystalline, polycrystalline and thin film copper indium gallium selenide (CIGS), based on measurements from a test facility and for varying meteorological conditions. The yield measurements of the panels from the site over a two-year period are used to develop the techno-economic indicator performance, for a proposed commercial installation. Measurements of solar irradiation and temperature are incorporated into a regression model for yield sensitivity analysis, which in turn is used to investigative the sensitivity of financial performance.It was seen that CIGS panels delivered on average 11.6% more yield when compared to monocrystalline technologies per kWp, with sustained outputs even during relatively colder periods. The improved financial performance of CIGS panels over monocrystalline panels was seen via a 24% increase in discounted return on investment, 7.8% reduction in payback period and 21% improvement in net present value. The regression model indicates that CIGS panel yields are less sensitive to lower solar irradiation and more sensitive towards higher temperatures. Overall variation of financial indicators for a range of yield outputs, is lowest for CIGS panels compared to both types of crystalline panels. CIGS panels show lower variability in financial returns particularly in conditions with higher temperatures that makes the results valid in geographical locations with higher temperatures and higher solar irradiation. The findings are useful for multiple stakeholders within the PV industry who have an interest in sub-Saharan Africa and the southern hemisphere, where such investigations are limited though solar resource is abundant.

Experimental examination of a thin-film photovoltaic panel power characteristics under constant load during October-March period in Mersin province

In this study, the power generated by a thin-film photovoltaic panel was measured under real atmospheric conditions in Mersin between October and March. The experimental setup involves a stand with adjustable inclination around a single axis, current meter and voltage meter, pyrometer, and two computers on a mobile rack. The power generated was determined as a function of solar irradiance using the data recorded with three minutes intervals in each measured day, during the six months period. The average generated power, irradiance, and efficiency were calculated for each measured month using the data collected. The generated power and efficiency values are found to be different from that of the values provided in photovoltaic panel manufacturer specifications.

Thermal regulation of photovoltaic panel installed in Upper Egyptian conditions in Qena

High ambient temperature and excessive solar radiation, especially in Upper Egypt, are essential factors in photovoltaic (PV) panel overheating, which in turn reduce its efficiency in such regions. Therefore, this study aims to develop a cooling system for the proposed thin-film PV panel installed in a harsh climate region in Qena City in Upper Egypt to obtain practically reasonable electrical efficiency. To achieve this target, three different cooling systems and operating modes were investigated: open-loop water-based cooling system, closed-loop water-based cooling system with free-convection air-cooled heat exchanger, and closed-loop water-based cooling system with forced-convection air-cooled heat exchanger using a DC fan. All these systems were supplemented with a fourth operating mode without cooling, i.e., normal conditions. The PV panel efficiency was experimentally investigated using the proposed cooling systems, and the experimental results demonstrated that without cooling, the daily average efficiency reached only approximately 6.2%, whereas it increased to 11.3% when the open-loop system was used. However, the daily average efficiency reached 8.5% using the closed-loop free-convection cooling system, and it reached 10.5% when the closed-loop forced-convection cooling system was used. Therefore, these cooling systems are highly recommended for application as effective techniques to increase the PV panel performance. The entire experimental data were obtained during a 10-h period from 7:00 a.m. to 5:00p.m.

Determination of a mathematical model of the thin-film photovoltaic panel (CIS) based on measurement data

Determination of a mathematical model of the thin-film photovoltaic panel (CIS) based on measurement data

Evaluation of the economic impact of a new high value process for the management of the end of life of thin film photovoltaic modules

This paper presents the evaluation of the economic impact in terms of valuable material recovered, and cost associated to the recycling, of a new method proposed for managing the end of life of thin film photovoltaic panels that has been developed by the Industrial Engineering and Mathematical Science Department of Universita Politecnica delle Marche. The revenues associated to the recovery of valuable and common materials, the avoided cost for landfill disposal, the recycling costs have been assessed for evaluating the sustainability of the process. Other aspects such as the potential damages for health and environment due to an improper management of the PV panels end of life phase, have been considered.

Recovery of valuable materials from end-of-life thin-film photovoltaic panels: environmental impact assessment of different management options

Abstract The present study deals with the management of end-of-life copper indium gallium selenide (CIGS) and cadmium telluride (CdTe) thin-film photovoltaic (PV) panels. We quantitatively compare the impacts and environmental weak points of the recycling processes of such panels, and their disposal in a landfill site. Two scenarios of recycling are considered: conventional and innovative. In the conventional recycling, the modules are crushed, glass is recovered, ethylene-vinyl acetate (EVA) is sent to thermal treatment to gain energy and the residual material is disposed of in a landfill site. Conversely, the innovative recycling option goes beyond conventional technologies and it allows to recover also selenium, indium and gallium from the CIGS panels, and tellurium from the CdTe panels. The potential impacts on the environment are similar for the conventional recycling processes of both the typologies of PV panels. Conversely, the innovative recycling of the CdTe panels creates a net production of environmental credits thanks to the recovery of valuable materials. The innovative recycling of CIGS panels has a higher impact than the recycling of CdTe panels (e.g. 2.5 vs 0.7 kg CO 2 -eq., respectively, for global warming potential). In any case, the disposal of end-of-life panels is not advantageous for the environment according to life cycle assessment. Data obtained with the recycling processes currently available suggest that the innovative recycling is environmentally beneficial only for the CdTe panels, due to the very low content of valuable elements in the CIGS panels. More effort should be directed to the development of a pre-treatment that can effectively concentrate the valuable elements. Overall, the results of this study give a quantitative basis to support the recycling of PV panels and the recovery of secondary raw materials like tellurium, indium, gallium and selenium.

Integration and Operation of a Single-Phase Bidirectional Inverter With Two Buck/Boost MPPTs for DC-Distribution Applications

This study is focused on integration and operation of a single-phase bidirectional inverter with two buck/boost maximum power point trackers (MPPTs) for dc-distribution applications. In a dc-distribution system, a bidirectional inverter is required to control the power flow between dc bus and ac grid, and to regulate the dc bus to a certain range of voltages. A droop regulation mechanism according to the inverter inductor current levels to reduce capacitor size, balance power flow, and accommodate load variation is proposed. Since the photovoltaic (PV) array voltage can vary from 0 to 600 V, especially with thin-film PV panels, the MPPT topology is formed with buck and boost converters to operate at the dc-bus voltage around 380 V, reducing the voltage stress of its followed inverter. Additionally, the controller can online check the input configuration of the two MPPTs, equally distribute the PV-array output current to the two MPPTs in parallel operation, and switch control laws to smooth out mode transition. A comparison between the conventional boost MPPT and the proposed buck/boost MPPT integrated with a PV inverter is also presented. Experimental results obtained from a 5-kW system have verified the discussion and feasibility.

Evaluation of the environmental benefits of new high value process for the management of the end of life of thin film photovoltaic modules

Abstract This paper presents the preliminary results of an environmental evaluation carried out by the application of Life Cycle Analysis (LCA), to a new method proposed for managing the end of life of thin film photovoltaic panels that is being developed by a company leader in design and installation of photovoltaic solutions. The new method is being developed in an experimental test facility established by the company for implementing a series of mechanical and hydro mechanical treatments to thin film panels at the end of their life before the ultimate material recovery phase. The main innovation of the method consists in the elimination of the thermal treatments and the reduction of chemicals needed for recovering valuable materials, in favor of mechanical processes. The results demonstrate that the mechanical treatments used in the pre-treatment phase of the module has a positive effect in almost all the damage categories defined in the LCA and contribute significantly to the reduction of the global warming and the carbon footprint of the photovoltaic technology.

Design, development and deployment of a hybrid renewable energy powered mobile medical clinic with automated modular control system

Abstract A renewable energy powered mobile medical clinic has been designed, developed and deployed in the Dominican Republic. The portable renewable energy system consists of a 46.5 m 2 (500 ft 2 ) tent powered by a suite of renewable energy technologies including a hybrid wind and photovoltaic system with a lithium-iron-phosphate (LiFePO 4 ) battery bank for energy storage. Thin-film photovoltaic panels integrated into the thermal fly of the tent are designed to generate 4.8 kW of power. In addition, the system consists of two wind turbines each capable of generating 1 kW, and are supported on portable towers which do not require guy wires or mountings into the ground. The system provides 3 kW of power continuously with a maximum renewable energy power generation of 6.8 kW. The Mobile Medical Clinic (MMC) was deployed in Mao, Dominican Republic. Due to the environmental conditions at this particular location a majority of the power generated by the renewable energy system came from the photovoltaic panels. The renewable energy system and energy storage system are backed up by a gasoline generator, which serves solely as a source of power in the absence of wind or solar energy and when the battery bank is discharged. The control system of the MMC automatically turns on and shuts off the generator as needed in order to minimize fuel consumption. The entire MMC including the renewable energy system was designed to be portable, scalable and all components man-liftable. The system is controlled by state-of-the-art off the shelf components and does not require a complex computer control system. The control system consists solely of the inverters and the charge controllers. The system has remained extremely effective and yet simple to operate which is beneficial since the purpose of the MMC is to operate in austere conditions with minimal training for the operators. The system has been donated to the Dominican Republic to be used for deployment during emergency response situations.

Fluorine Doped Tin Oxide Coatings - Over 50 Years and Going Strong

Thin film coatings of fluorine doped tin oxide on glass were first produced in the 1940’s as part of the World War II effort. Generically known as TCO (Transparent Conductive Oxide) Coatings, the primary use was for antifogging coatings for aircraft transparencies using an electrical current to heat the glass assembly. Nearly 60 years later, these coatings are still used in cockpit glazings. Although the first generation coatings were applied using spray pyrolysis on heated glass panes, by 1990 these coatings were being applied directly on the float glass ribbon during the primary glass manufacturing operation, using Atmospheric Pressure Chemical Vapor Deposition (APCVD). As part of a color suppressed multi-layer structure, these coatings met the aesthetic and performance criteria for architectural low E glazings, and spawned new applications in electrochromic devices, heated freezer doors, radiant glass heaters, EMI/RFI Shielding, and the largest growing segment in glass – thin film photovoltaic panels. In this paper we discuss the characteristics of the on-line production, the performance characteristics of the coatings, the end use requirements, and the massive infrastructure in place worldwide to support the volume requirements. We compare the properties of SnO2:F to other emerging TCO materials such as zinc oxide.