The integration of pumped hydro storage systems into PV microgrids in rural areas

Photovoltaic (PV) systems are popular in rural areas because they provide low cost and clean electricity for homes and irrigation systems. The primary challenge of PV systems is their intermittent nature. The typical solution is storing energy in batteries; however, they are expensive and possess a short lifespan. This research proposes a new type of pumped hydro storage (PHS) which can be implemented as an alternative to batteries. The components of the system are modelled to consider losses of the system accurately. The mathematic model developed in this project assists the management system to make more efficient decisions. The proposed storage is integrated into a farmhouse that has a PV pumping system where economic aspects of implementing the proposed storage is investigated. The integration of the proposed PHS into a microgrid needs a management system to make this system efficient and 3 cost-effective. This research proposes a multi-stage management system to schedule and control the microgrid components for optimal integration of the PHS. The designed management system is able to manage the pump, turbine, and irrigation time on real-time taking into account both present and future conditions of the microgrid. This study investigates the technical aspects of the proposed system. The PHS and the management system are tested experimentally in a setup installed at smart energy laboratory at Edith Cowan university. Data used in this project are real data collected in the laboratory in order to have a realistic analysis. Economic analysis is done in different sizes with different conditions. Results indicate that the proposed system has a short payback period and a large lifetime benefit, featuring as a cost-effective and sustainable energy storage system for use in rural areas. Video abstract: https://youtu.be/VuyEvHRY7W

Comparison of Microscopic Endodontic Techniques: A Systematic Review and Meta-Analysis

Objective: To evaluate the success rates of resin-based endodontic surgery (RES) and endodontic microsurgery (EMS), and compare their results. Material and Methods: A total of 19 and 34 full-text papers were reviewed, and finally, 2 and 6 studies were selected for RES and EMS, respectively. The stages of the study selection process were illustrated in Figure 1. The demographic characteristics were also described using the IBM SPSS Software, and the meta-analysis was fulfilled via Stata V.14. Results: A total number of 811 teeth were analyzed in this systematic review and meta-analysis, with a mean follow-up of 38.63 months. Besides, the results of the meta-analysis indicated that both methods not only differed in terms of implementation but also produced varying outcomes. Accordingly, EMS demonstrated a higher success rate likelihood with a significant difference from that of RES. Conclusion: An excellent proof was made available through this meta-analysis regarding the resin-based endodontic surgery success rate likelihood (79.9%) and an update for the endodontic microsurgery success rate possibility (100%)

Investigation of Scale-Forming and Corrosiveness Potential of Drinking Water (Case Study of Shiraz Drinking Water Distribution System)

This research was conducted to investigate the potential of scale forming and corrosiveness of drinking water in the reservoirs and drinking water distribution network in Shiraz, Iran.The area under study was divided into 17 zones. During winter, spring, and summer 2011, 144 water samples were collected from the water reservoirs and the various sites of water distribution system. The chemical parameters were measured. Then, values of the Langelier (LI), Rayznar (RI), Larson (LI) and aggressive (AI) indices were calculated for each sample. In this research, 41 samples of home pipes were collected from different zones of Shiraz and the rate of scale formation was calculated for each sample. The scale composition of 33 home pipe samples and 8 network pipe samples were analyzed by X-ray diffraction method. Results showed that the mean values of LI, RI, LS, and AI were 0.07 (considered as slightly scale forming), 7.1 (non-scale forming), 1.2 (corrosive), and 14 (non-corrosive) respectively. The average rate of scale formation and their values for the drinking water of Shiraz pipes is 0.26 mm/yr. The research found that the main compositions in the scale samples were calcium carbonate, calcium sulfate, magnesium carbonate, magnesium sulfate, hematite, maghemite, magnetite, goethite, zinc oxide, gypsum, vivianite, dolomite, hydroxyapatite, and troilite. The main elements in the scale samples were magnesium, silicon, phosphorus, sulfur, zinc, copper, and lead. According to the results of this research, zones located in the east, south, and southeast of Shiraz, because of high levels of hardness and sulfate exhibit more scale formation as a problem

Quantifying techno-economic indicators\u27 impact on isolated renewable energy systems

Addressing climate change with the rising global energy usage necessitates electricity sector decarbonization by rapidly moving toward flexible and efficient off-grid renewable energy systems (RESs). This paper analyzes the wind and solar micro-grids, with batteries and pumped hydro storage for a robust off-grid RES techno-economic operation, while considering diverse multi-objective optimization cases. This research has considered the RES variable operational losses in the developed methodology and relations between different indicators are evaluated, revealing a basic understanding between them. The results reveal that the reliability index is inversely related to the oversupply index, while directly related to the system self-sufficiency index. The cost of energy is more sensitive to technical indicators rather than the storage cost and so can be used as a primary monetary index. Energy and cost balance analysis showed that 16%-20% of the used energy was drained in RES operational losses, which were usually ignored in previous studies

Optimal sizing design and operation of electrical and thermal energy storage systems in smart buildings

Photovoltaic (PV) systems in residential buildings require energy storage to enhance their productivity; however, in present technology, battery storage systems (BSSs) are not the most cost-effective solutions. Comparatively, thermal storage systems (TSSs) can provide opportunities to enhance PV self-consumption while reducing life cycle costs. This paper proposes a new framework for optimal sizing design and real-time operation of energy storage systems in a residential building equipped with a PV system, heat pump (HP), thermal and electrical energy storage systems. For simultaneous optimal sizing of BSS and TSS, a particle swarm optimization (PSO) algorithm is applied to minimize daily electricity and life cycle costs of the smart building. A model predictive controller is then developed to manage energy flow of storage systems to minimize electricity costs for end-users. The main objective of the controller is to optimally control HP operation and battery charge/discharge actions based on a demand response program. The controller regulates the flow of water in the storage tank to meet designated thermal energy requirements by controlling HP operation. Furthermore, the power flow of battery is controlled to supply all loads during peak-load hours to minimize electricity costs. The results of this paper demonstrate to rooftop PV system owners that investment in combined TSS and BSS can be more profitable as this system can minimize life cycle costs. The proposed methods for optimal sizing and operation of electrical and thermal storage system can reduce the annual electricity cost by more than 80% with over 42% reduction in the life cycle cost. Simulation and experimental results are presented to validate the effectiveness of the proposed framework and controller

Prevalence and attributable health burden of chronic respiratory diseases, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Previous attempts to characterise the burden of chronic respiratory diseases have focused only on specific disease conditions, such as chronic obstructive pulmonary disease (COPD) or asthma. In this study, we aimed to characterise the burden of chronic respiratory diseases globally, providing a comprehensive and up-to-date analysis on geographical and time trends from 1990 to 2017. Methods Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, we estimated the prevalence, morbidity, and mortality attributable to chronic respiratory diseases through an analysis of deaths, disability-adjusted life-years (DALYs), and years of life lost (YLL) by GBD super-region, from 1990 to 2017, stratified by age and sex. Specific diseases analysed included asthma, COPD, interstitial lung disease and pulmonary sarcoidosis, pneumoconiosis, and other chronic respiratory diseases. We also assessed the contribution of risk factors (smoking, second-hand smoke, ambient particulate matter and ozone pollution, household air pollution from solid fuels, and occupational risks) to chronic respiratory disease-attributable DALYs. Findings In 2017, 544.9 million people (95% uncertainty interval [UI] 506.9- 584.8) worldwide had a chronic respiratory disease, representing an increase of 39.8% compared with 1990. Chronic respiratory disease prevalence showed wide variability across GBD super-regions, with the highest prevalence among both males and females in high-income regions, and the lowest prevalence in sub-Saharan Africa and south Asia. The age-sex- specific prevalence of each chronic respiratory disease in 2017 was also highly variable geographically. Chronic respiratory diseases were the third leading cause of death in 2017 (7.0% [95% UI 6.8-7 .2] of all deaths), behind cardiovascular diseases and neoplasms. Deaths due to chronic respiratory diseases numbered 3 914 196 (95% UI 3 790 578-4 044 819) in 2017, an increase of 18.0% since 1990, while total DALYs increased by 13.3%. However, when accounting for ageing and population growth, declines were observed in age-standardised prevalence (14.3% decrease), agestandardised death rates (42.6%), and age-standardised DALY rates (38.2%). In males and females, most chronic respiratory disease-attributable deaths and DALYs were due to COPD. In regional analyses, mortality rates from chronic respiratory diseases were greatest in south Asia and lowest in sub-Saharan Africa, also across both sexes. Notably, although absolute prevalence was lower in south Asia than in most other super-regions, YLLs due to chronic respiratory diseases across the subcontinent were the highest in the world. Death rates due to interstitial lung disease and pulmonary sarcoidosis were greater than those due to pneumoconiosis in all super-regions. Smoking was the leading risk factor for chronic respiratory disease-related disability across all regions for men. Among women, household air pollution from solid fuels was the predominant risk factor for chronic respiratory diseases in south Asia and sub-Saharan Africa, while ambient particulate matter represented the leading risk factor in southeast Asia, east Asia, and Oceania, and in the Middle East and north Africa super-region. Interpretation Our study shows that chronic respiratory diseases remain a leading cause of death and disability worldwide, with growth in absolute numbers but sharp declines in several age-standardised estimators since 1990. Premature mortality from chronic respiratory diseases seems to be highest in regions with less-resourced health systems on a per-capita basis