Search

This paper reports the design, characterization and implementation of a fiber Bragg grating (FBG)-based temperature sensor for an insulted-gate Bipolar transistor (IGBT) in a solar panel inverter. The FBG is bonded to the higher coefficient of thermal expansion (CTE) side of a bimetallic strip to increase its sensitivity. Characterization results show a linear relationship between increasing temperature and the wavelength shift. It is found that the sensitivity of the sensor can be categorized into three characterization temperature regions between 26 °C and 90 °C. The region from 41 °C to 90 °C shows the highest sensitivity, with a value of 14 pm/°C. A new empirical model that considers both temperature and strain effects has been developed for the sensor. Finally, the FBG-bimetal temperature sensor is placed in a solar panel inverter and results confirm that it can be used for real-time monitoring of the IGBT temperature.

Purpose: There is a strong inducement to develop new inorganic materials to substitute the current industrial pigments, which are known for their poor ultraviolet absorbent and low photoluminescence (PL) properties. The purpose of this paper is to invent a better rare-earth-based pigment material as a spectral modifier with good luminescence properties to enhance the spectral response for photovoltaic panel application. Design/methodology/approach: Different phosphor samples made of nano-calcium carbonate (CaCO3) with varied wt.% of the dopant Dysprosium doped calcium borophosphate (CBP/Dy) as (W0 – 0%, W1 – 3,85%, W2 – 7.41%, W3 –10.71% and W4 –13.79%) were prepared via the solid-state diffusion method at 600 °C for 6 h using a muffle furnace. The structural, morphological and luminescence properties of the CaCO3:CBP/Dy powder samples were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and PL test. Findings: The XRD, SEM and FTIR results verified the crystalline formation, morphological behaviour and vibration bonds of synthesized CBP/Dy-doped CaCO3 powder samples. XRD pattern revealed that the synthesized powder samples exhibit crystalline structured materials, and SEM results showed irregular shape and porous-like structured morphologies. FTIR spectrum shows prominent bands at 712, 874 and 1,404 cm−1, corresponding to asymmetric stretching vibrations of CO32− groups and out-of-plane bending. PL characterization of CBP/Dy-doped CaCO3 (sample W) shows emission at 427 nm (λmax) under the excitation of 358 nm. The intensity of PL emission spectra drops due to the concentration quenching effect, while the maximum PL intensity is observed in the W3 phosphor powder system. Research limitations/implications: This phosphor powder is expected to find out the potential application such as a spectral modifier which is applied to match the energy of photons with solar cell bandgap to improve spectral absorption and lead to better efficiency. Originality/value: The introduction of a nano-CaCO3:CBP/Dy hybrid powder system with good luminescence properties to be used as spectral modifiers for solar cell application has been synthesized in the lab, which is a novel attempt. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to introduce the simple synthesis process of thermal-insulation coating by using three different nanoparticles, namely, nano-zinc oxide (ZnO), nano-tin dioxide (SnO2) and nano-titanium dioxide (TiO2), which can reduce the temperature of solar cells. Design/methodology/approach: The thermal-insulation coating is designed using sol-gel process. The aminopropyltriethoxysilane/methyltrimethoxysilane binder system improves the cross-linking between the hydroxyl groups, -OH of nanoparticles. The isopropyl alcohol is used as a solvent medium. The fabrication method is a dip-coating method. Findings: The prepared S1B1 coating (20 Wt.% of SnO2) exhibits high transparency and great thermal insulation property where the surface temperature of solar cells has been reduced by 13°C under 1,000 W/m2 irradiation after 1 h. Meanwhile, the Z1B2 coating (20 Wt.% of ZnO) reduced the temperature of solar cells by 7°C. On the other hand, the embedded nanoparticles have improved the fill factor of solar cells by 0.2 or 33.33%. Research limitations/implications: Findings provide a significant method for the development of thermal-insulation coating by a simple synthesis process and low-cost materials. Practical implications: The thermal-insulation coating is proposed to prevent exterior heat energy to the inside solar panel glass. At the same time, it can prevent excessive heating on the solar cell's surface, later improves the efficiency of solar cell. Originality/value: This study presents a the novel method to develop and compare the thermal-insulation coating by using various nanoparticles, namely, nano-TiO2, nano-SnO2 and nano-ZnO at different weight percentage. [ABSTRACT FROM AUTHOR]

Among the renewable energy resources, solar thermal is one of the technologies that significantly contribute to energy supply and reduce global greenhouse gas (GHG) emissions. Solar water heating (SWH) contributes a large proportion of the global solar thermal capacity, with 63% installation for domestic hot water (DHW) systems, 28% for large DHW systems, and the remaining 9% for other applications such as swimming pools heating, solar district heating, and space heating. Still, now, there are many challenges and limitations of those SWH technologies. The present work reviews the current challenges faced in the domestic SWH industry globally. The integration of thermal energy storage (TES) systems for better collector's radiation absorption and overall performance are also highlighted. Many countries worldwide seem to face similar challenges within the SWH technologies and industry. It is proven that these challenges and limitations can hinder the global capacity of solar thermal utilization. [ABSTRACT FROM AUTHOR]

Maximum power point tracking (MPPT) and battery charging control are two important functions for a solar battery charger. The former improves utilization of the available solar energy, while the latter ensures a prolonged battery life. Nevertheless, complete implementation of both functions can be complex and costly, especially for low voltage application such as standalone street lamps. In this paper, the operation of a solar battery charger for standalone street light systems is investigated. Using only one voltage sensor, the solar charger is able to operate in both MPPT and constant voltage (CV) charging mode, hence providing high performance at a low cost. Using a lab prototype and a solar simulator, the operation of the charger system is demonstrated and its performance under varying irradiance is validated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Low cost passive islanding is developed for single phase grid connected inverter. [•] Drastically improved disconnection time in the proposed method for single phase inverter. [•] Low cost, effective and minimal of external components are the forte for this method. [•] Effectively detect islanding for different loads, inverter output powers and quality factors. [Copyright &y& Elsevier]

The performance and commercialization of dye sensitized solar cells is very much dependent on cost effective and robust catalyst. In this study, polyaniline (PANi) nano-rods have been synthesized and the effect of tungsten disulfite (WS 2) nanosheets has been investigated for the catalytic and electronic properties of polyaniline. Various concentrations of WS 2 nanosheets i.e., 1 wt%, 2 wt%, 5 wt% and 7 wt% have been used to examine the effect of concentration of WS 2 on overall electronic properties of PANi. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (TEM) have been employed for morphological studies. X-ray diffraction (XRD) patterns have been studied for compositional analysis. Fourier transformed infrared (FTIR) along with cyclic voltammetry (CV) have been utilized to investigate the catalytic activity in specified electrolyte and to identify unsaturated redox-active functionalities respectively. Sun simulator has been employed to study incident photo conversion efficiency (IPCE), open circuit voltage (Voc) and short circuit current (Isc). Finally, electron impedance spectroscopy has been employed to study the electronic resistance at the interfaces. An increase in overall electronic and device performance has been observed. The specimens containing 5 wt% WS 2 in PANi exhibited 7.32% IPCE which is 92.14% equivalent to platinum (Pt) counter electrode based reference DSSC. • A PANi-WS 2 nanocomposite has been investigated to replace Pt based CE. • The nanocomposite displayed remarkable electro-catalytic properties. • The PANi-5wt%WS 2 nanocomposite is 92.14% equivalent to standard Pt. • The proposed catalyst is cost effective and corrosion resistant compared to standard Pt. [ABSTRACT FROM AUTHOR]

• Self-cleaning approach towards enhancement of electrical efficiency. • Performance evaluation at five different volume flow rates. • Electrical efficiency enhanced from 9.89% to 11.91% as compared to PV only. • Maximum thermal efficiency found to be 77.60% at a mass flow rate of 2 LPM. This study experimentally investigates the potency of the designed and developed a photovoltaic thermal energy storage with self-cleaning (SC) sub-systems in improving the electrical efficiency of a solar photovoltaic system with thermal energy storage (PV-TES). The photovoltaic system with thermal energy storage (PV-TES) absorber is called double serpentine-flow channel, wherein phase change materials (PCM) thermal storage system has been integrated for better temperature control. An automatic self-cleaning system has been mounted on PV glass cover to clean the dust and ensure higher absorption of incident solar energy. The performance of self-cleaning assisted photovoltaic system with thermal energy storage (PV-TES-SC) has been studied under varied flow rate of 0.5 to 4 L per minute (LPM). Results shows that the PV-TES-SC attained a maximum thermal efficiency of 77.60% at a mass flow rate of 2 LPM. Else ways, the average maximum electrical efficiency of 11.91% was found at a mass flow rate of 4 LPM, whereas a PV alone system could deliver only 9.89% electrical efficiency. From the experimental results it can be confirmed that the PV-TES-SC system is efficient than a PV alone as a result of the newly introduced PCM thermal energy storage and self-cleaning system. [ABSTRACT FROM AUTHOR]

Carbonaceous thermal energy storage involving PCMs has gained an increasing research interest owing to their higher thermal conductivity and energy storage density. The current work analyses the thermophysical properties of a nano-enhanced eutectic phase change material (NeUPCM) laden with different concentrations (ranges from 0 wt% - 0.7 wt%) of multi-wall carbon nanotube (MWCNT). Paraffin wax-palmitic acid (PW-PA) binary eutectic was produced initially by facile melt blending, and then MWCNTs were doped via standard two-step nanocomposite synthesis protocol. Nanocomposites showed a slower decomposition rate, and the thermal resistance index improved. MWCNT enhance the thermal conductivity of the eutectic base (140 %), which reaches a maximum value of 0.619 W/(m·K) for 0.5 wt% loadings, and the maximum increment of 13.2 % of latent heat was noted for 0.7 wt% loading of MWCNT (which is having a melting temperature of 53 °C). The sample doped with 0.5 wt% MWCNT(C3) showed the highest thermal effusivity. The NeUPCMs also displayed improved photothermal performance and solar absorptivity. Corrosion analysis against copper revealed that the composite is suitable for long-term usage. The NeUPCMs maintained good reliability even after 500 melt-freeze cycles. In short, the proposed NeUPCMs hold significant potential to be employed for thermal energy storage purposes. [Display omitted] • Maximal enhancement of 140 % in thermal conductivity for nanocomposite. • MWCNT-tailored eutectic PCM (PW-PA) showed excellent thermal stability. • Nanocomposite displayed improved latent heat. • Nanocomposites displayed improved photothermal capability. • Proven thermal reliability even after 500 melt-freeze cycles. [ABSTRACT FROM AUTHOR]

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

Photovoltaic (PV) modules convert a small portion of solar radiation into electrical energy and convert the rest into heat. As a result, the temperature of these modules is increased and their electrical efficiency is degraded. In this study, the effects of various operating parameters, such as solar cell temperature, irradiation intensity, mass flow rate of cooling water, humidity, and dust, on the output performance of a PV module are investigated under outdoor operating conditions. A finned tube is placed at the bottom of the PV module for cooling. Results show that the electrical efficiency of the module decreases by 5.82% as solar cell temperature increases by 26.10 °C. The electrical efficiency also decreases by approximately 0.22% as the temperature of the PV module increases by 1 °C. As irradiation intensity increases by 100 W/m 2 , the solar cell temperature increases by 3.82 °C and the output power increases by 3.14 W, but the efficiency decreases by 0.85%. In summary, solar cell temperature, solar irradiation intensity, mass flow rate of cooling fluids, humidity, and dust significantly affect the performance of PV modules. [ABSTRACT FROM AUTHOR]

Abstract Amalgamation of thermal collector at the back of PV overcomes with low energy conversion efficiency issue upto some extent and improves overall efficiency of the systems. Use of phase change materials (PCM) in PV/T collectors as an intermediate thermal storage media offers a promising solution to this problem by storing large amount of heat. The aim of this research work was to design and develop a photovoltaic/thermal-phase change materials (PV/T-PCM) system and evaluate its energy, exergy and economic performance. Lauric acid as PCM contained in leak-proof aluminum foil packets are placed around the flow channel allowing extended period of thermal storage. The PV/T-PCM system has been studied at different volume flow rates viz. 0.5–4 L per minutes (LPM) to get the optimized performance of the system. Maximum thermal efficiency of PV/T-PCM collector was found to be 87.72% at 2 LPM. Maximum electrical efficiency of PV and PV/T-PCM systems has been found to be 9.88% and 11.08% (4LPM) respectively. The maximum exergy efficiency of PV and PV/T-PCM system has been found 7.09% and 12.19% (0.5 LPM) respectively. An economic analysis of the proposed system has also been carried out with a view to examine the feasibility of its commercialization. Highlights • Study of novel two side serpentine flow based photovoltaic/thermal (PV/T) with PCM. • Self-sufficient PVT-PCM system with improved energy and exergy efficiencies. • Economic evaluation of the PV/T collector using cash flow analysis. • Maximum thermal and exergy efficiency is found to be 87.72% and 12.19% respectively. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a comparative analysis has been presented on various topologies of isolated and non-isolated DC-DC converters. Here, the major focus remains on transformer-less (TL) DC-DC converters, based on the conventional basic boost converter. In addition, to attain high voltage gain, a classification of non-isolated converters based on extendable and non-extendable design has been presented. For comparative and theoretical analysis, the parameters chosen are the number of components utilized by each converter topology, high voltage gain offered, voltage stresses on each component involved and the efficiency of the high gain topologies. For the converters under discussion, operation under ideal and non-ideal conditions has also been highlighted. Based on this study, authors present a guide for the reader to identify various high voltage gain topologies for photovoltaic (PV) systems. Highlights • Present a wide range of isolated and non-isolated Dc – Dc converters. • Classify non-isolated Dc - Dc converters based on the design for extendable or non-extendable voltage gain. • A comparative analysis of different Dc – Dc converters, particularly focusing the non-isolated design. • Guide for future work on Dc – Dc converter topologies. [ABSTRACT FROM AUTHOR]

Highlights • Explain the operation of the proposed high gain Boost and buck-boost converters based on extendable Switch Capacitor cells. • Highlight the modes of operation for the proposed converters to justify converter utility for stand-alone PV systems. • Comparatively analyse the voltage gain and efficiency of the proposed converters against the conventional converters. • Guide for future work on B-BBC with extendable SC cells. Abstract This paper presents transformerless high gain boost and buck-boost DC-DC converters (B-BBCs) with extendable switched capacitor cells (SCs), suitable for applications operating at high voltage, above 300 V. Boosting low voltage to a high-enough level, with low duty ratio, is beyond the practical capability of the conventional boost converter. In addition, high duty ratio needed for operation of the boost converter, results in higher component stress that suppresses the overall efficiency of the converter. Therefore, by a convenient integration of SCs with conventional B-BBCs, increased voltage gain is attained with fewer losses. Such converters can be employed for Photovoltaic (PV) systems. The operational principles and modes of operation are analyzed to justify the utility of converters for stand-alone PV systems. Moreover, the proposed modular structure allows to increase SC cells in order to obtain reduced voltage stress on switching components with a higher voltage gain. Simulation and experimental results based on 100 W laboratory prototype extol the theoretical analysis. [ABSTRACT FROM AUTHOR]