9 research outputs found
Electricity system security in Jordan: A response for arab uprising
Jordan energy sector is characterized by the high dependency on imported energy and high growth rate of energy demands. The location of Jordan in a conflict hot spot makes the energy security of high interest for the Jordanian policy maker. This article investigates the impact of regional conflicts on Jordanian energy sector and tracks the development of electricity system security before and after the first wave of Arab uprising and the turmoil associated with it. An electricity sector security framework consisting of eleven indices is built based on Stirling four properties of energy security, which are durability, stability, robustness and resilience. The framework is used to compare the security of the system in 2018 with 2010. This article argues that the development in the security during the study period is a response of the Arab uprising based on authoritarian learning phenomena. The results are validated by comparing the expected generation costs and CO2 emissions based on actual development with development scenarios found in literature. A forecasting model is reproduced for this purpose. The results of the forecasting model support the conclusion reached by the security framework. This is due to the responsive policies followed by the Jordanian government and the grants given by Gulf countries to enhance Jordanâs stability. It was concluded that even a specific conflict can have negative impacts on the energy sector in a neighboring country in short terms, it can have positive impacts in medium and long term if a rational and sustainable response plan is adopted
Enhancing the Geometrical Performance Using Initially Conical Cylinder Liner in Internal Combustion Engines - A Numerical Study
Reducing friction is an important aspect to increase the efficiency of internal combustion engines (ICE). The majority of frictional losses in engines are related to both the piston skirt and piston ringâcylinder liner (PRCL) arrangement. We studied the enhancement of the conformation of the PRCL arrangement based on the assumption that a suitable conical liner in its cold state may deform into a liner with nearly straight parallel walls in the fired state due to the impact of mechanical and thermal stresses. Combining the initially conical shape with a noncircular cross section will bring the liner even closer to the perfect cylindrical shape in the fired state. Hence, a significant friction reduction can be expected. For the investigation, the numerical method was first developed to simulate the liner deformation with advanced finite element methods. This was validated with given experimental data of the deformation for a gasoline engine in its fired state. In the next step, initially conically and/or elliptically shaped liners were investigated for their deformation between the cold and fired state. It was found that, for liners being both conical and elliptical in their cold state, a significant increase of straightness, parallelism, and roundness was reached in the fired state. The combined elliptical-conical liner led to a reduced straightness error by more than 50% compared to the cylindrical liner. The parallelism error was reduced by 60% to 70% and the roundness error was reduced between 70% and 80% at different liner positions. These numerical results show interesting potential for the friction reduction in the piston-liner arrangement within internal combustion engines
Cost Analysis of Implementing In-Pipe Hydro Turbine in the United Arab Emirates Water Network
Water transmission lines have potential reserved energy, which is usually lost. Therefore, targeting this clean energy to produce electricity to power up the auxiliaries and utilities of water plants or consumers is financially and environmentally beneficial. This paper aims to investigate the feasibility of installing an inline hydropower system in an existing transmission water pipe. It analyzes the feasibility of implementing a mini-hydropower plant in the transmission line of Liwaâs reservoir in the UAE. The maximum possible power harvested is 218.175 kW at the given water flow rate and net head. The payback period and the return on investment are analyzed based on different scenarios related to capital investment, operation, maintenance cost, and plant capacity factor. It is found that the payback period ranges between one to six years, where the return on investment can be as high as 85%. Furthermore, the expected CO2 emissions saving for this project is calculated to be between 395 and 1939 tons per year
Investigation of the trends of electricity demands in Jordan and its susceptibility to the ambient air temperature towards sustainable electricity generation
Background: Efficient production and reliable availability of electricity requires comprehensive understanding of load demand trends to plan and match production with consumption. Although electricity demand depends on a combination of cultural and economic conditions, weather conditions remain as the major driver. With increased capabilities of accurate predictions of weather, the importance of investigating and quantifying its impact on electricity demand becomes obvious. The electrical system in Jordan has been facing several challenges including the failure to respond to increased demands induced by extreme temperatures. This paper covers a clear gap in literature through presenting a detailed investigation of the electricity consumption trends and in identifying the susceptibility of these trends to weather. Methods: This study relies on the statistical processing and analysis, through modeling of hourly electricity demands in Jordan in the period of 10âyears between 2007 and 2016. Actual weather data was used employing the degree-day approach. The monthly, daily, and hourly seasonal variation indices were determined. Optimally formulated piecewise functions were used to track the thermal comfort zone and rate of increase in electricity demand for temperatures beyond it for each year. Moreover, the elasticity of polynomial functions was adopted to identify saturation points to thermally map the electricity consumption.
Results: The developed models successfully described the relationship between the daily electricity demand and the mean daily ambient temperature. The average comfort zone width was 4â°C and the average mean base temperature was 17.9â°C. The sensitivity of electricity demand to both high and low temperatures has increased on average, with 11% and 16.4% to hot and cold weather, respectively. Finally, the electricity demand in cooling was found to saturate at 32.9â°C, whereas it saturates for heating at 4.7â°C. Conclusions: The electricity demand in Jordan observes seasonal trends in a consistent and predictable manner. An optimally formulated piecewise function successfully tracked the thermal comfort zone and the rate of increase in electricity demand for temperatures beyond it for each year of the study period. Finally, saturation heating and cooling temperatures were acquired from the elasticity of the daily electricity demands modeled against daily HDD and CDD
Entwicklung innovativer Konzepte fĂŒr Zylinderlaufbuchsen von Verbrennungsmotoren mit numerischen Simulationsmethoden
Internal combustion engine (ICE) represents the main pillar of the powertrain in the majority of road, marine freight, and transportation worldwide. With the absence of a real alternative that can replace ICE over its full range of applications, enhancing the efficiency of ICE is of great interest to save energy and reduce greenhouse gas emissions. A great improvement potential is seen in the piston ring â cylinder liner (PRCL) coupling which is responsible to maintain the combustion pressure in the cylinder while preventing lubricant oil leak to it. Large frictional losses are associated with this sealing function. In order to improve the PRCL conformability with less friction, a rounder liner cross section is targeted in the hot operational state. The rounder the liner is, the better conformability exists. To achieve that, the engine must be started with a non-circular liner that deforms in a controlled manner under engine thermal and mechanical loads to form a circular liner bore during the fire operation. Further tribological improvement can be achieved by targeting a non-prismatic circular bore shape in the hot operational state. This cumulative thesis presents numerical investigations to this reverse engineering approach with the aim to reach a specific liner shape in the fire operation state from non-cylindrically produced liners in the cold state. It follows the relevant research hypothesis and provides quantitative analysis to show the advantages and limitations of such an approach. The presented numerical work is based on advanced simulation techniques established on the basis of finite element methods. Two physical models were considered; one for a series gasoline engine, and the second for a single cylinder diesel engine test rig. The models were validated using experimental data, then the local deformations of the liners were simulated. Harmonic analysis was used to investigate the orders of deformations and their trends over a set of operational points. Then different forms of non-circular liners were designed based on the reverse engineering concept. Geometrical performance indicators were developed and used in the comparative analysis. The results show a significant improvement in the geometrical performance when using non-circular liners. Special freeform liner can improve the bore roundness by 95% and the straightness by 75%. The concept of dominant deformation order can simplify the design significantly. For example, the elliptical conus liner is a good yet simpler alternative with 85% improvement in roundness and 65% in the straightness of the liner during fire operation. The freeform liner is susceptible to the engine load. However, some deformation orders are independent of operational points and can be considered in the liner design. The results presented here show a great potential of tribological improvement. A parallel experimental work shows a significant reduction of frictional losses by using one of the liners that was designed in this thesis.Ein erhebliches Potenzial zur Verbesserung von Verbrennungsmotoren liegt in der verbesserten Kopplung von Kolbenringen und Zylinder Laufbuchsen (Piston Ring Cylinder Coupling, PRCL). Um die KonformitĂ€t von PRCL zu verbessern und die Reibung zu verringern, wird in einem gefeuerter Betrieb eine möglichst kreisförmige Querschnittsform der Laufbuchse angestrebt. Je weiter sich der Querschnitt der Laufbuchse eines Kreises annĂ€hert, desto besser ist die KonformitĂ€t. Um dies zu erreichen, muss der Motor im kalten Zustand eine nicht-kreisförmige Laufbuchse haben, die sich unter thermischen und mechanischen Belastungen des gefeuerten Motors kontrolliert verformt und dann eine Laufbuchse mit ideal kreisförmigem Querschnitt bildet. DarĂŒber hinaus können weitere tribologische Verbesserungen erzielt werden, indem im gefeuerten Betrieb eine nicht-prismatische, kreisförmige Laufbuchse angestrebt wird. Diese kumulative Arbeit prĂ€sentiert numerische Untersuchungen fĂŒr diese Hypothese und liefert quantitative Analysen, um die Vor- und Nachteile mit nicht-kreisförmigen Laufbuchsen aufzuzeigen. DarĂŒber hinaus werden Richtlinien fĂŒr das Design nicht-kreisförmiger Freiformlaufbuchsen dargelegt.
Die Simulationsmodelle dieser Arbeit basieren auf der Finite-Elemente-Methode. Zwei physikalische Modelle wurden betrachtet: Eines fĂŒr einen Serien-Gasmotor und ein zweites fĂŒr einen Einzylinder-Forschungsmotor. Die Modelle wurden anhand experimenteller Daten validiert, woraufhin die lokalen Verformungen der Laufbuchsen simuliert wurden. Unter Anwendung der harmonische Analyse wurden die Deformationsordnungen fĂŒr definierte Betriebspunkte untersucht. Darauf aufbauend wurden verschiedene Formen von nicht-kreisförmigen Laufbuchsen basierend auf dem Konzept des Reverse Engineering ausgelegt. Geometrische Indikatoren wurden definiert und in vergleichenden Analysen verwendet. Die Ergebnisse zeigen eine signifikante Verbesserung des geometrie-bedingten Verhaltens bei Verwendung von nicht-kreisförmigen Laufbuchsen. Eine speziell entwickelte Freiformlaufbuchse kann die Rundheit der Bohrung um 95 % und die Geradheit um 75 % verbessern. Das Konzept der fĂŒhrenden Deformationsordnungen ermöglicht eine signifikante Vereinfachung des Designs. Als Beispiel hierfĂŒr ist eine elliptische Konuslaufbuchse eine gute, jedoch einfachere Alternative, die eine Verbesserung der Rundheit um 85 % und der Geradheit der Laufbuchse um 65 % wĂ€hrend des Betriebs aufweist. Die Freiformlaufbuchse ist empfindlich bezĂŒglich der Motorenlast. Da bestimmte Deformationsordnungen jedoch unabhĂ€ngig vom Betriebspunkt sind, können diese bei der Laufbuchsengestaltung besonders berĂŒcksichtigt werden. Die hier prĂ€sentierten Ergebnisse zeigen ein groĂes Potenzial zur tribologischen Verbesserung. Parallel stattfindende experimentelle Arbeiten zeigen eine signifikante Reduzierung der Reibungsverluste durch die Verwendung einer in dieser Arbeit entwickelten Laufbuchsen
Syrian Refugeesâ Integration Policies in Jordanian Labor Market
The Government of Jordan declared that there are more than one million Syrian refugees in Jordan while UNHCR statistics show that the number is about 700,000. Nonetheless, it is still a large problem for Jordan, especially since there is no real solution that seems to be looming on the horizon for the Syrian crisis. Consequently, that means that those refugeesâ stay in Jordan is indefinite. This fact requires Jordan to work towards solutions to avoid the warehousing of those refugees in camps and to integrate them in Jordanian community to ease their stay in Jordan. To achieve that integration, Jordan must facilitate the Syriansâ access to the Jordanian labor market so they can achieve self-reliance. In February 2016, donors gathered in London for the âSupporting Syria and the Regionâ conference, known as the London Conference, to mobilize funding for the needs of the people affected by the Syrian crisis. In that conference, Jordan pledged to facilitate Syrian refugeesâ access to the labor market. This paper will study the process of Syrian integration in Jordanian society by discussing the policies and the procedures that Jordan has developed to facilitate the Syriansâ access to the labor market. The event study method combined with interviews and desk research were used to evaluate the new policies and procedures developed to facilitate this access. It was found that Jordan succeeded in creating a legal and procedural environment that facilitates Syriansâ access to formal jobs, and the Syrians went a long way toward integration in Jordan. Nonetheless, they are still not fully integrated
Electricity system security in Jordan: A response for arab uprising
Jordan energy sector is characterized by the high dependency on imported energy and high growth rate of energy demands. The location of Jordan in a conflict hot spot makes the energy security of high interest for the Jordanian policy maker. This article investigates the impact of regional conflicts on Jordanian energy sector and tracks the development of electricity system security before and after the first wave of Arab uprising and the turmoil associated with it. An electricity sector security framework consisting of eleven indices is built based on Stirling four properties of energy security, which are durability, stability, robustness and resilience. The framework is used to compare the security of the system in 2018 with 2010. This article argues that the development in the security during the study period is a response of the Arab uprising based on authoritarian learning phenomena. The results are validated by comparing the expected generation costs and CO2 emissions based on actual development with development scenarios found in literature. A forecasting model is reproduced for this purpose. The results of the forecasting model support the conclusion reached by the security framework. This is due to the responsive policies followed by the Jordanian government and the grants given by Gulf countries to enhance Jordanâs stability. It was concluded that even a specific conflict can have negative impacts on the energy sector in a neighboring country in short terms, it can have positive impacts in medium and long term if a rational and sustainable response plan is adopted
Structural Performance of Additively Manufactured Cylinder LinerâA Numerical Study
Climate change is exacerbated by vehicle emissions. Furthermore, vehicle pollution contributes to respiratory and cardiopulmonary diseases, as well as lung cancer. This requires a drastic reduction in global greenhouse gas emissions for the automobile industry. To address this issue, researchers are required to reduce friction, which is one of the most important aspects of improving the efficiency of internal combustion engines. One of the most important parts of an engine that contributes to friction is the piston ring cylinder liner (PRCL) coupling. Controlling the linear deformation enhances the performance of the engine and, as a result, contributes positively to its performance. The majority of the tests to study the conformability between cylinder liner and piston were carried out on cylinder liners made of cast iron. It is possible to improve the performance of piston ring cylinder liner couplings by implementing new and advanced manufacturing techniques. In this work, a validated finite element model was used to simulate the performance when advanced manufactured materials were adapted. The deformation of the cylinder liner due to thermal and mechanical loads is simulated with five different additive manufactured materials (Inconel 625, Inconel 718, 17-4PH stainless steel, AlSi10Mg, Ti6Al4V). Simulated roundness and straightness errors, as well as maximum deformation, are compared with conventional grey cast iron liner deformation. Some additive manufactured materials, especially Ti6Al4V, show a significant reduction in deformation compared to grey cast iron, both in bore and circumferential deformation. Results show that Ti6Al4V can reduce maximum liner deformation by 36%. In addition, the roundness improved by 36%. The straightness error when Ti6Al4V was used also improved by 44% on one side, with an average of 20% over the four sides. Numerical results indicate that additive manufactured materials have the potential to reduce friction within the piston liner arrangement of internal combustion engines
Cost Analysis of Implementing In-Pipe Hydro Turbine in the United Arab Emirates Water Network
Water transmission lines have potential reserved energy, which is usually lost. Therefore, targeting this clean energy to produce electricity to power up the auxiliaries and utilities of water plants or consumers is financially and environmentally beneficial. This paper aims to investigate the feasibility of installing an inline hydropower system in an existing transmission water pipe. It analyzes the feasibility of implementing a mini-hydropower plant in the transmission line of Liwa’s reservoir in the UAE. The maximum possible power harvested is 218.175 kW at the given water flow rate and net head. The payback period and the return on investment are analyzed based on different scenarios related to capital investment, operation, maintenance cost, and plant capacity factor. It is found that the payback period ranges between one to six years, where the return on investment can be as high as 85%. Furthermore, the expected CO2 emissions saving for this project is calculated to be between 395 and 1939 tons per year