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Load Flow Solution of the Tanzanian Power Network Using Newton-Raphson Method and MATLAB Software
Issue:
Volume 3, Issue 6, December 2014
Pages:
277-286
Received:
15 November 2014
Accepted:
27 November 2014
Published:
5 December 2014
Abstract: Load flow studies are the backbone of power system analysis and design. They are necessary for planning, operation, optimal power flow and economic scheduling and power exchange between utilities. This paper describes modelling procedure and present models of system components used in performing load flow analysis. The developed models are joined together to form a system network representing an approximate Tanzanian power network model. A load flow problem is formulated using the model and a MATLAB program developed using Newton-Raphson algorithm is applied in solving the problem. Simulation results are presented and analysed. The results indicate that the voltage magnitude and voltage phase angle profiles are within the operating limits of the system; it means that the selection of system components and modelling process is appropriate and accurate. The results will form the basis of other critical power system studies of the network in the future such as power system state estimation, optimal power flow and security constrained optimal power flow studies.
Abstract: Load flow studies are the backbone of power system analysis and design. They are necessary for planning, operation, optimal power flow and economic scheduling and power exchange between utilities. This paper describes modelling procedure and present models of system components used in performing load flow analysis. The developed models are joined t...
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Assessment on Passive Cooling Techniques to Improve Steel Roof Thermal Performance in Hot Tropical Climate
Madi Kabore,
Etienne Wurtz,
Yézouma Coulibaly,
Adamah Messan,
Patrice Moreaux
Issue:
Volume 3, Issue 6, December 2014
Pages:
287-295
Received:
25 November 2014
Accepted:
9 December 2014
Published:
18 December 2014
Abstract: In African hot tropical climate countries, due to climate and the unsuitability of construction materials, building’s indoor environment remains over the thermal comfort acceptable limit over long periods of time during the year. Among the building envelope components, roof is a critical part that is highly susceptible to solar radiation. Solutions like passive cooling and low energy consumption systems are not explored enough in those countries. These techniques and systems can be used to meet a large part of the cooling needs and reduce the overheating period in buildings, but their applicability depends on the climate zone. In this paper, investigations were conducted to determine their potential to improve steel roof performance for free running buildings under tropical climatic conditions. The case studies are two configurations (with and without attic) of typical steel roof in Burkina Faso. Using dynamic simulation, we have evaluated the impacts of radiant barrier, insulation, cool paint and ventilation for two configuration of roofing. For both configurations, high reflective solutions perform very well. It also appears that the attic case due to its actual configuration (shape and design) and to the climate conditions ventilation does not perform very well. These results can help building actors during the design process.
Abstract: In African hot tropical climate countries, due to climate and the unsuitability of construction materials, building’s indoor environment remains over the thermal comfort acceptable limit over long periods of time during the year. Among the building envelope components, roof is a critical part that is highly susceptible to solar radiation. Solutions...
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Heating and Cooling Hybrid System and Method for Its Calculation and Design
Issue:
Volume 3, Issue 6, December 2014
Pages:
296-307
Received:
8 December 2014
Accepted:
24 December 2014
Published:
31 December 2014
Abstract: In this article newly developed heating and cooling hybrid system is discussed. The system combines a heat pump, heating boiler and solar air heater. Low temperature source of heat pump is a gas mixture composed of waste warm gases, like inside used ventilation air, flue gases of heating boiler (smock), as well as outside air, heated in solar air heater. The evaporator of heat pump is installed in waste warm gases mixing chamber, aiming at avoiding the main disadvan¬tage of ordinary air sourced heat pump, in case of which the evaporator surface in wintertime is covered with ice crust that obstructs movement of air through the evaporator of heat pump. To solve the problem it is suggested to create a mixture of waste warm gases gathered in a gas mixing chamber and serving as heat source. A method for calculation and design of the new system was developed for both winter heating and summer cooling of a building. The energy and economic investigation based on mathematical model proved rather high cost effectiveness and energy efficiency of developed heating and cooling hybrid system.
Abstract: In this article newly developed heating and cooling hybrid system is discussed. The system combines a heat pump, heating boiler and solar air heater. Low temperature source of heat pump is a gas mixture composed of waste warm gases, like inside used ventilation air, flue gases of heating boiler (smock), as well as outside air, heated in solar air h...
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A System Dynamics Model for Energy Planning in Niger
Yacouba Moumouni,
Sajjad Ahmad,
R. Jacob Baker
Issue:
Volume 3, Issue 6, December 2014
Pages:
308-322
Received:
15 December 2014
Accepted:
6 January 2015
Published:
19 January 2015
Abstract: This paper proposes an energy management model using system dynamics (SD) modeling approach. The time span of the model extends from 2003 to 2030. The Model was calibrated and used for the evaluation of six policy scenarios. Population, per capita electricity consumption, and the industrial sectors were identified as key components and used as inputs to predict future electricity supply and demand needs. Particular attention was paid, in the proposed model, to the individual and total amounts of carbon released into the atmosphere. Finally, to demonstrate the usefulness of the model, it was applied to Niger’s electricity sector. The raw data from the past ten years was used as a benchmark for the study. A key factor in this study was Niger’s fast growing population. The quick increase in population will add uncertainties to both the projections and the accuracy of the results. Model results show that by putting a particular emphasis on the national supply, Niger may be energy self-sufficient from 2018 through 2030. The model also indicates that the bond between Nigeria and Niger must be firmly re-strengthened for the latter to be able to meet its future electricity challenges. The proposed model can be used in guiding public policy in developing regions.
Abstract: This paper proposes an energy management model using system dynamics (SD) modeling approach. The time span of the model extends from 2003 to 2030. The Model was calibrated and used for the evaluation of six policy scenarios. Population, per capita electricity consumption, and the industrial sectors were identified as key components and used as inpu...
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Thermal Analysis of the Combustion Chamber of an Industrial Hot Water Spray Washing Machine
Ashimedua Ogochukwu Godwin,
Enibe Samuel Ogbonna,
Kebodi Chiedu Lawrence
Issue:
Volume 3, Issue 6, December 2014
Pages:
323-330
Received:
17 December 2014
Accepted:
30 December 2014
Published:
20 January 2015
Abstract: The thermal analysis of an industrial hot water spray washing machine using hot air from the combustion of diesel fuel to heat up water that flows through a spirally coiled steel tube heat exchanger inside a steel shell combustion chamber was analyzed. The working fluids used are water and air. The spirally coiled tube is made by bending a 15mm diameter and 3 mm thick straight pipe into 4 turns and 9 layers respectively. The total length of the tube is approximately 20m. Water at ambient temperature flows into the coil through the outermost turn and flows out through the innermost turn. The adiabatic flame temperature of the fuel was determined. The in-tube and the outside convective heat transfer coefficients were determined using the appropriate correlations available in literature. A mathematical model of the heat transferred to the water was formulated and solved using the Engineering Equation Solver (EES). The results obtained are in reasonable agreement with measured data. Parametric study was done to determine the effects of each parameter on the outlet water temperature.
Abstract: The thermal analysis of an industrial hot water spray washing machine using hot air from the combustion of diesel fuel to heat up water that flows through a spirally coiled steel tube heat exchanger inside a steel shell combustion chamber was analyzed. The working fluids used are water and air. The spirally coiled tube is made by bending a 15mm dia...
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Resource Assessment and Optimization Study of Efficient Type Hybrid Power System for Electrification of Rural District in Ethiopia
Samuel Tesema,
Getachew Bekele
Issue:
Volume 3, Issue 6, December 2014
Pages:
331-340
Received:
19 December 2014
Accepted:
6 January 2015
Published:
30 January 2015
Abstract: The Somali region in Ethiopia enjoys an average wind speed of 5m/s at 10m elevation and an average daily solar radiation of 7.5kwh/m2/day. Within this perspective, a remote rural village in Somali region calledWerder district (6050'N 45030' E) can be electrified with a stand-alone hybrid renewable energy system. The village is far away from the national electric grid and the electrical load density in the village is low. Extension of national grid to this village which is located 576km away from national grid is not economically feasible. Therefore, this study aims to explore techno-economic analysis of electrifying the village with hybrid renewable energy. The software HOMER was used in this study to evaluate the technical and economic feasibility of various hybrid energy alternatives to the village. The economic analysis compares the levelized cost of electricity generation for the three option; wind/PV/diesel generator, diesel generator only system and national grid extension. The levelized cost focusing on the elements causing differences such as fuel price, PV modules, with battery or generator rather than the elements that are similar across the technology choices (distribution, metering, etc). The finding indicate that photovoltaic/wind/diesel generator hybrid system was feasible systems based on some important parameters such as high renewable penetration, less annual diesel consumption, less carbon dioxide emission, less unmet load, less capacity shortage and cost of energy. A thermal load (boiler) is added to the system that uses the excess power generation during the night rather than dissipating it to the dump load; which greatly improved the efficiency of the system at small cost of diesel to the boiler.
Abstract: The Somali region in Ethiopia enjoys an average wind speed of 5m/s at 10m elevation and an average daily solar radiation of 7.5kwh/m2/day. Within this perspective, a remote rural village in Somali region calledWerder district (6050'N 45030' E) can be electrified with a stand-alone hybrid renewable energy system. The village is far away from the nat...
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