Estimation of daily flow rate of photovoltaic water pumping systems using solar radiation data

This paper presents a simple model which allows us to contribute in the studies of photovoltaic (PV) water pumping systems sizing. The nonlinear relation between water flow rate and solar power has been obtained experimentally in a first step and then used for performance prediction. The model proposed enables us to simulate the water flow rate using solar radiation data for different heads (50 m, 60 m, 70 m and 80 m) and for 8S × 3P PV array configuration. The experimental data are obtained with our pumping test facility located at Madinah site (Saudi Arabia). The performances are calculated using the measured solar radiation data of different locations in Saudi Arabia. Knowing the solar radiation data, we have estimated with a good precision the water flow rate Q in five locations (Al-Jouf, Solar Village, AL-Ahsa, Madinah and Gizan) in Saudi Arabia. The flow rate Q increases with the increase of pump power for different heads following the nonlinear model proposed. Keywords: Photovoltaic water pumping system, Solar radiation data, Simulation, Flow rat

The economic feasibility analysis of generated photovoltaic energy in the USTO campus

The aim of this study is to analyze the economic impact of photovoltaic energy generation by a prospective campus microgrid to be installed at the University of Science and Technology (USTO). In this work, hourly solar irradiation and temperature data provided from the local weather office is used to study the distribution and duration of solar radiation over the campus. The generated solar photovoltaic energy is analyzed taking into account the economic aspects such as the photovoltaic system capital investment cost and the annual power generation cash flow. The installed power of the photovoltaic plant was calculated and the generated energy estimed. The feasility analysis shows a payback year of of 10,3, an internal rate of return of 5% and a profitability index of 1. © 2019, Wydawnictwo SIGMA-NOT. All rights reserved

A renal registry for Africa: first steps.

There is a dearth of data on end-stage renal disease (ESRD) in Africa. Several national renal registries have been established but have not been sustainable because of resource limitations. The African Association of Nephrology (AFRAN) and the African Paediatric Nephrology Association (AFPNA) recognize the importance of good registry data and plan to establish an African Renal Registry. This article reviews the elements needed for a successful renal registry and gives an overview of renal registries in developed and developing countries, with the emphasis on Africa. It then discusses the proposed African Renal Registry and the first steps towards its implementation. A registry requires a clear purpose, and agreement on inclusion and exclusion criteria, the dataset and the data dictionary. Ethical issues, data ownership and access, the dissemination of findings and funding must all be considered. Well-documented processes should guide data collection and ensure data quality. The ERA-EDTA Registry is the world's oldest renal registry. In Africa, registry data have been published mainly by North African countries, starting with Egypt and Tunisia in 1975. However, in recent years no African country has regularly reported national registry data. A shared renal registry would provide participating countries with a reliable technology platform and a common data dictionary to facilitate joint analyses and comparisons. In March 2015, AFRAN organized a registry workshop for African nephrologists and then took the decision to establish, for the first time, an African Renal Registry. In conclusion, African nephrologists have decided to establish a continental renal registry. This initiative could make a substantial impact on the practice of nephrology and the provision of services for adults and children with ESRD in many African countries

A Low Cost Concept for Data Acquisition Systems Applied to Decentralized Renewable Energy Plants

The present paper describes experiences of the use of monitoring and data acquisition systems (DAS) and proposes a new concept of a low cost DAS applied to decentralized renewable energy (RE) plants with an USB interface. The use of such systems contributes to disseminate these plants, recognizing in real time local energy resources, monitoring energy conversion efficiency and sending information concerning failures. These aspects are important, mainly for developing countries, where decentralized power plants based on renewable sources are in some cases the best option for supplying electricity to rural areas. Nevertheless, the cost of commercial DAS is still a barrier for a greater dissemination of such systems in developing countries. The proposed USB based DAS presents a new dual clock operation philosophy, in which the acquisition system contains two clock sources for parallel information processing from different communication protocols. To ensure the low cost of the DAS and to promote the dissemination of this technology in developing countries, the proposed data acquisition firmware and the software for USB microcontrollers programming is a free and open source software, executable in the Linux and Windows® operating systems

Strengthening Renal Registries and ESRD Research in Africa

CITATION: Davids, M. R., et al. 2017. Strengthening renal registries and ESRD research in Africa. Seminars in Nephrology, 37(3):211-223, doi:10.1016/j.semnephrol.2017.02.002.The original publication is available at http://www.seminarsinnephrology.orgENGLISH ABSTRACT: In Africa the combination of non-communicable diseases, infectious diseases, exposure to environmental toxins and acute kidney injury related to trauma and childbirth are driving an epidemic of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Good registry data can inform the planning of renal services and can be used to argue for better resource allocation, audit the delivery and quality of care, and monitor the impact of interventions. Few African countries have established renal registries and most have failed due to resource constraints. In this paper we briefly review the burden of CKD and ESRD in Africa then consider the research questions which could be addressed by renal registries. We describe examples of the impact of registry data and summarise the sparse primary literature on country-wide renal replacement therapy (RRT) in African countries over the past 20 years. Finally, we highlight some initiatives and opportunities for strengthening research on ESRD and RRT in Africa. These include the establishment of the African Renal Registry and the availability of new areas for research. We also discuss capacity-building, collaboration, open access publication and the strengthening of local journals, all measures which may improve the quantity, visibility and impact of African research outputs.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaarhttp://www.seminarsinnephrology.org/article/S0270-9295(17)30002-5/fulltextPostprin

Measurement of meteorological data based on wireless data acquisition system monitoring

Estimation of solar energy potential of a region requires detailed solar radiation climatology, and it is necessary to collect extensive radiation data of high accuracy covering all climatic zones of the region. In this regard, a wireless data acquisition system (WDAS) would help to estimate solar energy potential considering the remote region's energy requirement. This article explains the design and implementation of WDAS for assessment of solar energy. The proposed system consists of a set of sensors for measuring meteorological parameters. The collected data are first conditioned using precision electronic circuits and then interfaced to a PC using RS232 connection via wireless unit. The LabVIEW program is used to further process, display and store the collected data in the PC disk. The proposed architecture permits the rapid system development and has the advantage of flexibility and it can be easily extended for controlling the renewable energy systems like photovoltaic system. The WDAS with executive information systems and reporting tools helps to tap vast data resources and deliver information.Wireless data acquisition system Remote weather station LabVIEW monitoring Micro-controller Renewable energy sources

Optimization of tilt angle for solar panel: Case study for Madinah, Saudi Arabia

This article analyzes the optimal choice of the tilt angle for the solar panel in order to collect the maximum solar irradiation. In this paper, the collector surface is assumed to be facing toward equator. The study is based upon the measured values of daily global and diffuse solar radiation on a horizontal surface. It is shown that the optimal angle of tilt ([beta]opt) for each month, allows us to collected the maximum solar energy for Madinah site. Annual optimum tilt angle is found to be approximately equal to latitude of the location. It is found that the loss in the amount of collected energy when using the yearly average fixed angle is around 8% compared with the monthly optimum tilt [beta]opt.Solar panel Solar radiation Optimum tilt angle Modeling Isotropic models Anisotropic models