Abstract: Determining the optimum angle for a solar panel is important if tracking systems are not used and a tilt angle remains constant. This article determines the sensitivity of the optimum angle to surface reflectivity at different latitudes using a mathematical model that accounts for direct, diffuse and reflected radiation. A quadratic correlation is also developed to compute the optimal angle and maximum energy as a function of latitude and reflectivity. We also seek to determine how sensitive the optimal tilt angle is to cloud cover using the 35° latitude of the Prosperity solar facility in Albuquerque, NM.
Abstract: It is well known that the Low-Voltage DC (LVDC) distribution system is a promising topology as a future smart distribution system due to its high efficiency and reliability. However, there are still some challenges in the construction and implementation of an LVDC system. For practical application of the LVDC system, therefore, it is necessary to perform any simulation in advance by considering various conditions that can occur in an LVDC system. In order to provide a foundation for analyzing a DC system, this paper presents an LVDC distribution system model including essential components such as power electronic devices, Distributed Energy Resource (DER), and Energy Storage System (ESS), which can be considered for implementation in an LVDC system using Electro-Magnetic Transient Program (EMTP) software. Moreover, an analysis of the characteristic in both the steady state and the transient state is conducted in an LVDC distribution system.
Abstract: The paper presents a Supervision, Control, Data Acquisition and Simulation (SCADA & Simulator) system that allows for real-time training in the actual operation of a modular PEM fuel cell system. This SCADA & Simulator system consists of a free software tool that operates in real time and simulates real situations like failures and breakdowns in the system. This developed SCADA & Simulator system allows us to properly operate a fuel cell and helps us to understand how fuel cells operate and what devices are needed to configure and run the fuel cells, from the individual stack up to the whole fuel cell system. The SCADA & Simulator system governs a modular system integrated by three PEM fuel cells achieving power rates higher than tens of kilowatts.
Abstract: Many people in African countries lack access to sufficient electricity supply due to missing infrastructure of the centralized conventional power generation system. In order to provide electricity to a wider part of the population, it is necessary to exploit the vast renewable resources in African countries. Therefore, this paper scrutinizes the economic advantages of photovoltaic-based hybrid systems over fossil fuel-based power generation. A simulation model is applied in order to calculate the cost advantage of hybrid systems compared to diesel-only systems for the entire continent on a long term basis by applying two scenarios: one based on world market diesel prices and the other one based on national diesel prices. The results indicate that average power generation costs per country can be reduced by up to 0.11 €/kWh considering world market diesel prices and by up to 0.48 €/kWh considering national diesel prices. Furthermore, the effect of diesel fuel subsidies and taxes on the renewable energy potential and the respective savings are examined. These findings may ameliorate the policy development according to fossil fuel subsidies and taxes and demonstrate the advantages of decentralized renewable hybrid systems especially in rural areas of Africa.
Abstract: In the Silurian Dolostone region of eastern Wisconsin, the combination of thin soils and waste application (animal manure, organic waste) has led to significant groundwater contamination, including Brown Water Incidents (BWIs—contamination resulting in a color or odor change in well water) and detections of pathogen indicator bacteria such as E. coli and others. In response, a Karst Task Force (KTF) was convened to identify risks and recommend solutions. This article looks at the impact eight years after the 2007 Karst Task Force report—both the actions taken by local resource managers and the changes to water quality. We present the first regional analysis of the 2007 Karst Task Force report and subsequent regulatory changes to determine if these regulations impacted the prevalence of wells contaminated with animal waste and the frequency of BWIs. While all of the counties in the KTF area promoted increased awareness, landowner/manager and waste applicator education alone did not result in a drop in BWIs or other water quality improvements. The two counties in the study that adopted winter manure spreading restrictions on frozen or snow-covered ground showed statistically significant reductions in the instances of BWIs and other well water quality problems.
Abstract: The microbiological and chemical drinking water quality of 20 vulnerable Finnish small groundwater supplies was studied in relation to environmental risk factors associated with potential sources of contamination. The microbiological parameters analyzed included the following enteric pathogens: Giardia and Cryptosporidium, Campylobacter species, noroviruses, as well as indicator microbes (Escherichia coli, intestinal enterococci, coliform bacteria, Clostridium perfringens, Aeromonas spp. and heterotrophic bacteria). Chemical analyses included the determination of pH, conductivity, TOC, color, turbidity, and phosphorus, nitrate and nitrite nitrogen, iron, and manganese concentrations. Giardia intestinalis was detected from four of the water supplies, all of which had wastewater treatment activities in the neighborhood. Mesophilic Aeromonas salmonicida, coliform bacteria and E. coli were also detected. None of the samples were positive for both coliforms and Giardia. Low pH and high iron and manganese concentrations in some samples compromised the water quality. Giardia intestinalis was isolated for the first time in Finland in groundwater wells of public water works. In Europe, small water supplies are of great importance since they serve a significant sector of the population. In our study, the presence of fecal indicator bacteria, Aeromonas and Giardia revealed surface water access to the wells and health risks associated with small water supplies.