Prospects of Back Surface Field Effect in Ultra-Thin High-Efficiency CdS/CdTe Solar Cells from Numerical Modeling

Polycrystalline CdTe shows greater promises for the development of cost-effective, efficient, and reliable thin film solar cells. Results of numerical analysis using AMPS-1D simulator in exploring the possibility of ultrathin, high efficiency, and stable CdS/CdTe cells are presented. The conventional baseline case structure of CdS/CdTe cell has been explored with reduced CdTe absorber and CdS window layer thickness, where 1 μm thin CdTe and 50 nm CdS layers showed reasonable efficiencies over 15%. The viability of 1 μm CdTe absorber layer together with possible back surface field (BSF) layers to reduce minority carrier recombination loss at the back contact in ultra thin CdS/CdTe cells was investigated. Higher bandgap material like ZnTe and low bandgap materials like Sb2Te3 and As2Te3 as BSF were inserted to reduce the holes barrier height in the proposed ultra thin CdS/CdTe cells. The proposed structure of SnO2/Zn2SnO4/CdS/CdTe/As2Te3/Cu showed the highest conversion efficiency of 18.6% (Voc = 0.92 V, Jsc = 24.97 mA/cm2, and FF = 0.81). However, other proposed structures such as SnO2/Zn2SnO4/CdS/CdTe/Sb2Te3/Mo and SnO2/Zn2SnO4/CdS/CdTe/ZnTe/Al have also shown better stability at higher operating temperatures with acceptable efficiencies. Moreover, it was found that the cells normalized efficiency linearly decreased with the increased operating temperature with relatively lower gradient, which eventually indicates better stability of the proposed ultra thin CdS/CdTe cells

Review of materials for adsorption refrigeration technology

Purpose: During the last 20 years, interest in the closed adsorption heat pump and refrigeration systems has increased steadily. In this paper, consideration is given to aspects of adsorption refrigeration in terms of existing materials used in adsorption refrigeration, heat transfer characteristics of materials, and cost of materials and manufacturing. Design/methodology/approach: The paper is a general review of adsorption refrigeration technology. Findings: In recent years several papers have been published in this area and many aspects of the system have been addressed. Much effort has been devoted to enhance materials properties. Originality/value: The paper provides information of value to those involved with heat pump and refrigeration systems technology

Research and Development Aspects on Chemical Preparation Techniques of Photoanodes for Dye Sensitized Solar Cells

The importance of dye sensitized solar cells (DSSCs) as a low-cost and environmentally friendly photovoltaic (PV) technology has prompted many researchers to improve its efficiency and durability. The realization of these goals is impossible without taking into account the importance of the materials in DSSCs, so the focus on the preparation/deposition methods is essential. These methods can be either chemical or physical. In this study, the chemical applied methods that utilize chemical reaction to synthesize and deposit the materials are covered and categorized according to their gas phase and liquid phase precursors. Film processing techniques that can be used to enhance the materials' properties postpreparation are also included for further evaluation in this study. However, there is a variety of consideration, and certain criteria must be taken into account when selecting a specific deposition method, due to the fact that the fabrication conditions vary and are unoptimized

Parametric study on the thermal performance and optimal design elements of solar air heater enhanced with jet impingement on a corrugated absorber plate

Previous works revealed that cross-corrugated absorber plate design and jet impingement on a flat absorber plate resulted in a significant increase in the performance of a solar air heater (SAH). Involving these two designs into one continuous design to improve the SAH performance remains absent in the literature. This study aimed to evaluate the achieved enhancement on performance parameters of a SAH with jet impingement on a corrugated absorber plate. An energy balance model was developed to compare the performance parameters of the proposed SAH with the other two SAHs. At a clear sky day and a mass flow rate of 0.04 kg/s, the hourly results revealed that the max fluid outlet temperatures for the proposed SAH, jet-to-flat plate SAH, and cross-corrugated plate SAH are 321, 317, and 313 K, respectively; the max absorber plate temperatures are 323.5, 326.5, and 328 K, respectively; the maximum temperature differences between the absorber plate and fluid outlet are ~3, 9, and 15 K, respectively; the max efficiencies are 65.7, 64.8, and 60%, respectively. Statistical t -test results confirmed significant differences between the mean efficiency of the proposed SAH and SAH with jet-to-flat plate. Hence, the proposed design is considered superior in improving the performance parameters of SAH compared to other designs

Experimental study of the effect of fully shading on the Solar PV module performance

Experimental tests were performed to study the effects of shading for different string inside the photovoltaic (PV) panels, power equipped with different number of diodes from the same manufacturer as of solar panel. The IV curve for all cases were recorded to see how the bypass diodes will reduce the effects of shading .The case for 3 by pass diode show the best performance of solar PV module under shading phenomena

Wind Energy Potential of Jordan

The daily mean wind speed data for 5 locations in Jordan over a period of 9 years are collected and analyzed. Data are fitted to the Weibull distribution function. Weibull parameters are derived from the cumulative function of the observed data records (1989-1997), and used to calculate the mean wind speed and variance of the theoretical distribution. The goodness of representing the observed distribution with the Weibull distribution is determined using the Kolmogorov-Smirnov (K-S) test. At the 1% and 5% levels of confidence the observed data are well represented by the Weibull distribution. The annual mean values of the wind speed of the observed and theoretical distributions are 6.10ms-1 and 6.26ms-1 for Ras.Monief, 4.79ms-1 and 4.77ms-1 for Aqaba, 3.07ms-1 and 3.15ms-1 for Amman and 3.09ms-1 and 3.13ms-1 for Irbid and 2.34ms-1 and 2.40ms-1 for Der Alla respectively. Based on the annual wind speed, wind resource forRas.Monief, Aqaba, Amman, Irbid and Der Alla are varied from very good to poor. The annual mean power density of Ras.Monief, Aqaba, Amman, Irbid and Der Alla are 261.76 Wm-2, 118.95 Wm-2, 57.45 Wm-2, 40.95 Wm-2, and 24.97 Wm-2 respectively. Values of the power density obtained from the manufacturer’s power distribution curve of a 300MW wind turbine at a hub height of 10 meters are also given for comparison. The result of the analysis showed that only Ras.Monief and Aqaba have good wind energy potential

The role of climatic-design-operational parameters on combined PV/T collector performance: a critical review

PV/T technology attracted numerous researchers and professionals during the last decades. There are many review papers in the literature evaluated the R&D aspects of PV/T collectors. In fact, there are abundant of case studies discussed the parameters of climate, design and operational conditions affected the PV/T collector performance. But, a comprehensive compilation of the information of those case studies is still a missing link in the literature. Hence, this paper intended to review thoroughly the information regarding the parameters affecting the PV/T collector performance mainly and PV module performance partially. The parameters are supported with the most available R&D to measure the accurate influence of each parameter on the performance. The outcomes from the study are highlighted in lessons learned section

Characteristics and outcomes of 627 044 COVID-19 patients living with and without obesity in the United States, Spain, and the United Kingdom

Altres ajuts: This research received partial support from the National Institute for Health Research (NIHR) Oxford Biomedical Research Center (BRC), US National Institutes of Health, US Department of Veterans Affairs, Janssen Research & Development, and IQVIA. The University of Oxford received funding related to this work from the Bill & Melinda Gates Foundation (Investment ID INV016201 and INV-019257). APU has received funding from the Medical Research Council (MRC) [MR/K501256/1, MR/N013468/1] and Fundación Alfonso Martín Escudero (FAME) (APU). VINCI [VA HSR RES 13-457] (SLD, MEM, KEL). JCEL has received funding from the Medical Research Council (MR/K501256/1) and Versus Arthritis (21605). MR is funded by Wereld Kanker Onderzoek Fonds (WKOF), as part of the World Cancer Research Fund International grant program [grant number: 2017/1630]A detailed characterization of patients with COVID-19 living with obesity has not yet been undertaken. We aimed to describe and compare the demographics, medical conditions, and outcomes of COVID-19 patients living with obesity (PLWO) to those of patients living without obesity. We conducted a cohort study based on outpatient/inpatient care and claims data from January to June 2020 from Spain, the UK, and the US. We used six databases standardized to the OMOP common data model. We defined two non-mutually exclusive cohorts of patients diagnosed and/or hospitalized with COVID-19; patients were followed from index date to 30 days or death. We report the frequency of demographics, prior medical conditions, and 30-days outcomes (hospitalization, events, and death) by obesity status. We included 627 044 (Spain: 122 058, UK: 2336, and US: 502 650) diagnosed and 160 013 (Spain: 18 197, US: 141 816) hospitalized patients with COVID-19. The prevalence of obesity was higher among patients hospitalized (39.9%, 95%CI: 39.8−40.0) than among those diagnosed with COVID-19 (33.1%; 95%CI: 33.0−33.2). In both cohorts, PLWO were more often female. Hospitalized PLWO were younger than patients without obesity. Overall, COVID-19 PLWO were more likely to have prior medical conditions, present with cardiovascular and respiratory events during hospitalization, or require intensive services compared to COVID-19 patients without obesity. We show that PLWO differ from patients without obesity in a wide range of medical conditions and present with more severe forms of COVID-19, with higher hospitalization rates and intensive services requirements. These findings can help guiding preventive strategies of COVID-19 infection and complications and generating hypotheses for causal inference studies