volume-07-Issue 2 (2014)
IJTEE, volume-07, Issue 2 (2014) , PP 133 - 138
Published: 13 Jun 2014
by Isam Janajreha, Dana Suwwana, Hassan Fath from Mechanical Engineering Program, Masdar Institute of Science& Technology, Abu Dhabi, UAE, Environmental Engineering, Egypt-Japan University of Science and Technology (E-JUST), Alexandria, Egypt
Abstract: Computational Fluid Dynamics (CFD) is used to study the steady state performance of Low Energy Direct Contact Membrane Distillation (DCMD). Two-dimensional numerical model with parallel and counter flow is developed. A case of fully developed pressure driven parabolic flow is considered entering the domain at the feed and the permeate sides at 40 C and 25 C, respectively. The model parameters were measured in the consideration of two dimensional fluid flow governed by the complete Navier-Stokes coupled with the energy equation for non-isothermal laminar flow. The feed stream is water at water 4% salinity, whereas the permeate stream is comprised of pure water. Across the membrane the temperature difference creates a pressure gradient responsible for the transport of vapor mass through the pours of the permeable membrane. The vapor flow is driven by two mechanisms, Knudson and Poiseuille flow. The membrane’s coefficients of DCMD membrane is evaluated along with the mass flux, heat flux, and temperature polarization factor and results showed a good agreement with the published theoretical work. In view of these plausible results, parametrical study is carried out accounting for parallel and counter flow, different flow rates and inlet temperature in an attempt to achieve optimal or better yield to the Multi stage flashing method. read more... read less...
Keywords: Desalination, Direct Contact Membrane Distillation, Mass Transfer, Heat Transfer, Temperature Polarization
Polar Auxin Transport: Understanding the Effects of Temperature and Precipitation on Polar Auxin Transport in Polytrichum Ohioense Could Develop a Moss into a Climate Change Bioindicator
IJTEE, volume-07, Issue 2 (2014) , PP 125 - 131
Published: 13 Jun 2014
by Dorothy Belle Poli, Bryan T. Piatkowski, Geoffrey A. Bader, Jessica N. Branning, Laura E. Kellam from Roanoke College, Salem, Virginia, 24153, USA
Abstract: In an attempt to better understand polar auxin transport in the sporophytes of Polytrichum ohioense, a 5.3 fold increase in basipetal and acropetal transport was observed when temperature and precipitation varied significantly throughout the growing seasons. Wild plants were transferred into cultures and allowed to develop in temperatures that represented a “Warm Summer, Cold Winter” condition. Spores were grown on soil and watered to represent precipitation of a “Wet Fall, Winter” year. Traditional polar auxin transport assays were done on all sporophytes to calculate the amount of auxin transported in a polar fashion. The amount of water available to the developing sporophyte appears to be critical to polar auxin transport physiology; the temperature has less of an effect. This study also suggests that as climate change occurs, moss will be unequally affected by environmental factors. An additional benefit of this study suggests that polar auxin transport assays may be developed to monitor climatic change read more... read less...
Keywords: Polar auxin transport, Bryophytes, Polytrichum ohioense, climate change, monitoring
IJTEE, volume-07, Issue 2 (2014) , PP 109 - 124
Published: 13 Jun 2014
by Yousif Al-Abd, Toufic Mezher from Masdar Institute of Science and Technology, Abu Dhabi, UAE
Abstract: United Arab Emirates (UAE) is one of the developing countries that depend on hydrocarbon products in supporting its economy, where oil activities counted for 49.38 % of its total GDP (Gross Domestic Product) in 2009. Therefore, Abu Dhabi (AD), the capital of the UAE, has a vision wherein 2030 the country will decrease its dependency on fossil fuel to 36% in order to stabilize the economy. Through AD strategy, a number of new industries have been planned to enter in order to diversify the economy. Some of the investments are believed to be a very high tech and innovation driven industries, such as the aerospace manufacturing industry. The aim of this paper is to analyze different countries' national systems of innovation, which have been selected based on literature where innovation is measured through the number of KPIs (Key Performance Indices; R&D expenditures, number of research institutions, patents, number of engineers, new companies established, exports, etc). KPIs will be mapped from an innovation system perspective including the ones from UAE. Then a gap analysis will be conducted to determine where the country lags in terms of establishing a healthy national innovation system. A number of strategies will be suggested to enhance the UAE national innovation system. read more... read less...
Keywords: Innovation, Networks, Technology, Knowledge, R&D, Institutions, Universities, Engineering
IJTEE, volume-07, Issue 2 (2014) , PP 101 - 107
Published: 13 Jun 2014
by Jordi Ortiga, Joan Carles Bruno and Alberto Coronas from Universitat Rovira i Virgili, CREVER-Group of Applied Thermal Engineering, Tarragona, Spain, 43007
Abstract: Polygeneration systems refers to highly efficiency integrated systems characterized by the simultaneously production of different services (electricity, heating, cooling, water, etc) by means of several technologies using fossil and/or renewable energy sources. In many cases it is difficult to promote polygeneration projects due to its complexity. This complexity mainly comes from the high energy integration of the technologies involved in polygeneration plants and the high variability in the energy demand in many applications in the building sector that makes the design and optimal operation of these systems quite complex. The result is that without a very careful design and operation of these plants the economic viability is in many cases not clear. In this paper is presented an economic, energetic and environmental analysis of a polygeneration system in Cerdanyola del Vallès (Spain) built in the framework of the Polycity project of the European Concerto Program. This polygeneration system comprises three high efficient natural gas cogeneration engines with a total power capacity of about 10 MW with advanced thermal cooling facilities including a single effect hot water driven chiller and a double effect chiller of 5 MW driven directly by the exhaust gases of the engines. This plant provides electricity, heating and cooling to a new Science and Technological Park in development including a Synchrotron Light Facility through a district heating and cooling network with a total length of more than 30 km. The operational data for the energy performance analysis was taken using the plant SCADA system and a monitoring system specific for the cooling units in order to study in detail its performance. The results show that the polygeneration plant is an efficient way to reduce the primary energy consumption and CO2 emissions although it is not yet at its full capacity. read more... read less...
Keywords: polygeneration, trigeneration, modular design, high efficiency, district heating and cooling
IJTEE, volume-07, Issue 2 (2014) , PP 95 - 99
Published: 13 Jun 2014
by T. Tabazah, M. A. Hamdan, O. Abo Deyab and E. Abdelhafez from Department of Mechanical Engineering, Al-Zaytoonah University of Jordan, Amman, 11733 Department of Mechanical Engineering, University of Jordan, Amman, Jordan, 11942
Abstract: In this work an electrolyzer is used to produce Brown gas (HHO) from water by supplying a DC electrical power to it. the produced HHO was fed directly into the diesel line before being introduced into a domestic boiler. The effect of the added amounts of HHO to the diesel fuel on both the performance of the boiler and on the amount of emitted pollutants during the combustion process was investigated. It was found that the combustion efficiency of the boiler is improved with the amount of the HHO added, also it was found that the emitted pollutants was noticeably reduced with the added amounts of HHO. read more... read less...
Keywords: Brown gas, Hydrogen,Domestic heating, Water electrolysis
IJTEE, volume-07, Issue 2 (2014) , PP 87 - 93
Published: 13 Jun 2014
by Mohammad Hamdan, Lubna Badri and Eman Abdelhafez from Department of Mechanical Engineering, Al-Zaytoonah University of Jordan, Amman, Jordan Department of Computer and Communication Engineering, Al-Zaytoonah University of Jordan, Amman, Jordan
Abstract: The objective of the study was to assess the sensitivity of the Artificial Mural Networks (ANN) predictions to different combinations of input parameters as well as to determine the minimum amount of inputs necessary to accurately model solar still performance. Satisfactory results for the triple solar still suggest that, with sufficient input data, the ANN method could be extended to predict the performance of other solar still designs in different climate regimes. To accomplish this objective, a study has been performed to determine the effectiveness of triple solar still efficiency (η) using ANNs. The study used the following parameters as an input to the ANN: time, hourly variation of cover glass temperature (Tg), water temperature in the upper basin (Tw1), water temperature in the middle basin (Tw2) and water temperature in the lower basin of the triple basin still (Tw3), distillate volume, ambient temperature (Ta), plate temperature (TP) and hourly solar intensity (Is). read more... read less...
Keywords: Artificial Neural Network, sensitivity test, Feed forward, Solar Still
IJTEE, volume-07, Issue 2 (2014) , PP 79 - 85
Published: 16 Jun 2014
by R. Benelmir, N. Ghilen, M. El Ganaoui, D. Descieux and S. Gabsi from Faculty of Sciences and Technology Lab. LERMAB (UdL/INRA/Labex ARBRE) University of Lorraine, France
Abstract: Energy cogeneration is a way to improve global efficiency of energy production systems since it consumes a unique resource in order to supply heat and electrical power through optimal use of heat fluxes associated to power production. Energy trigeneration enlarges the concept to the production of cold also. It consumes a unique resource to produce electricity, heat and cold. Nevertheless, we could go more ahead by substituting a part of the primary fuel resource by renewable energy as solar energy in order to reduce the carbon impact. This is conducted through the use of adsorption refrigeration which needs hot water to produce cold water. However, even if energy utilities are provided with the best efficient way, the final use of energy could make all the efforts fall. Cooling ceilings present one of the best solutions to be coupled to solar cooling since it needs a medium range cold temperature of the fluid in order to avoid condensation if the wall ceiling temperature drops below the ambient air dew point temperature. All these constraints need to be checked experimentally and confronted to numerical simulation. For this purpose, an experimental platform has been developed combining an internal combustion gas engine (cogenerator), a refrigerating adsorption machine, thermal solar collectors and wooden construction split in two compartment, a cold one conditioned by cooling ceilings and a hot one conditioned by heating floors. The platform is completely instrumented. In this paper we focus only on the refrigeration machine for which we developed a simulation model that is confronted to experimental measurements. read more... read less...
Keywords: tri-generation, solar cooling, adsorption machine
IJTEE, volume-07, Issue 2 (2014) , PP 73 - 78
Published: 13 Jun 2014
by Rana El-Guindy, Maged K. Mahmoud from Regional Center for Renewable Energy and Energy Efficiency, Cairo, Egypt
Abstract: Most of the Arab countries energy systems are currently characterized at the same time by an increasing growth in electricity demand coupled with a high reliance on conventional fossil fuels in their electric power generation. This trend is expected to continue in the near and medium terms. Relying on conventional fossil fuels for electricity generation causes generally un- priced side-effects through their impacts on climate, human health, crops, structures and biodiversity, which are typically expressed as externalities. Unfortunately, externalities cost estimations are often based on quite diverse assumptions, making comparisons difficult. The main objective of this paper is to quantify for the first time the externalities of electric power generation in RCREEE Arab Member States. The paper summarizes recent literature in this area and addresses the question of environmental externalities of electric power generation, showing that estimates of external costs resulting from fossil fuels technologies if internalized into the price of the produced electricity, could lead to the result that some renewable energy projects are financially competitive with conventional power plants. Recognition of externalities costs and their “hidden” impact can actually serve to accelerate the process of transition towards more deployment of renewable energy projects in the Arab region. read more... read less...
Keywords: Externalities, electricity generation, fossil fuel, renewable energy
IJTEE, volume-07, Issue 2 (2014) , PP 65 - 72
Published: 13 Jun 2014
by Syed Shabbar Raza, Isam Janajreh from Masdar Institute of Science and Technology, Abu Dhabi, UAE
Abstract: Gasification is a high temperature thermo-chemical pathway that is used to convert a solid fuel/feedstock into combustible syngas (CO and H2) and chemicals. The gasified species derive their formation energy by combusting 20- 30% of the feedstock. The combustion resulted in emission of soot, particulate matter, NOx and SOx. Therefore, an attempt is made in this work to offset the energy required for gasification through the use of concentrated solar power, i.e. solar to enthalpy. The system consists of a parabolic and hyperbolic reflector using Cassegrain configuration to concentrate 5 kW of solar flux for the gasifier. Furthermore, a high fidelity computational fluid dynamics (CFD) simulation is established based on the results of thermodynamic and optical models. The CFD simulation couples the effect of heat transfer through solar radiation and reaction kinetics in the participating media. The results demonstrate a cold gasification efficiency of 90% with the product mole fraction of CO and H2 of 0.22 and 0.32, respectively, thereby suggesting the viability and large scale implementation of the system read more... read less...
Keywords: solar assisted gasification, cassegrain configuration, solar to chemical
IJTEE, volume-07, Issue 2 (2014) , PP 57 - 64
Published: 13 Jun 2014
by Chaouki Ghenai from Ocean and Mechanical Engineering Department, College of Engineering and Computer Science, Florida Atlantic University, 777 Glades Road, 36-177, Boca Raton, Florida, 33431 U.S.A.
Abstract: This paper presents information on the interconnections or linkages between the energy, water and carbon foot prints. The concerns, issues and challenges regarding the energy production, water consumption and climate change for the Middle Eastern and North African (MENA) countries will be discussed. The population and economic growth will drive the MENA energy demand. The energy demand is expected to double by 2030. The MENA electrical power generation sector relies on fossil fuels (natural gas and oil) and it is producing high greenhouse gas (GHG) emissions per capita. MENA countries have the lowest per capita water resources but the water consumption is very high. Sustainable solution methods and strategies with respect to water use and management, electrical power generation and CO2 emissions are needed. Water is a key element in energy resource (coal, natural gas, oil, and uranium) extraction, refining and processing; electric power generation using conventional and alternative energy systems (fossil fuel and nuclear power plants using steam turbines, concentrated solar power CSP and hydro power); cooling of power plants; and CO2 emission control technology (CO2 scrubbing process – remove of CO2 from power plant gas stream). Sustainable energy systems for power generation (solar PV and wind power or water free electrical power generation), and new alternative cooling systems for fossil and nuclear power plants are needed to reduce water consumption and CO2 emissions. A large amount of energy is also used and high CO2 emissions are produced to extract, supply, treat and use fresh water and for desalination plants. A water oriented strategies (conservation, efficiency, reuse, smart fresh water use and renewable energy systems for desalination plants) can significantly reduce the energy consumption and CO2 emissions. The development of sustainable and water free electrical power generation systems and smart water management strategies will contribute to the mitigation of the climate change caused by increasing greenhouse gas (GHG) emissions. read more... read less...
Keywords: Water-Energy-Carbon Nexus, MENA Countries, Water for Energy, Energy for Water, Sustainable Solutions and Strategies, Renewable Energy, Energy Efficiency, Water Management, Climate Change
Special Issue Devoted to Selected Papers from the Eleventh Arab Academy of Sciences International Conference on "Water-Energy Nexus and Waste Water Treatment for a Sustainable Arab World"
IJTEE, volume-07, Issue 2 (2014) , PP 55 - 56
Published: 30 Sep 2014
by Isam Janajreh from Mechanical and Materials Engineering Dept., Masdar Institute of Science and Technology, Abu Dhabi, UAE
Abstract: This is the 11th annual Meeting of the Arab Academy of Sciences. It was attended by experts in the areas of renewable energy, water treatment, as well as waste recycling and treatment from the Middle East and North Africa, Europe and North America. Following the opening welcome of the Arab Academy secretary by, Prof. Elias Baydoun, the president of the Academy His Excellency Prof. Adnan Badran delivered an inspiration speech addressing the water-energy thread in Arab world. Over the two days, four thematic sessions were targeted: (i) Innovative Water Treatment Technologies for the Arab World, (ii) Alternate and Efficient Energy Systems for the Arab Middle East (iii) Environmental Remediation Strategies (iv) Smart Grids which was entrained in the form of a panel discussion, Two Keynote talks were addressed during the technical sessions: The 1st was “Alternate Energy: Geothermal Energy, Alternate Solid Fuels”, and the 2nd was “Educational Programs on Sustainable Energy and Entrepreneurship”. Fifty-six delegates representing over 25 nationalities attended the meeting which included 26 invited talks. The panel session on, “Smart Grids” had participants from both academia and industry and government which included a lively discussion on electricity conservation by minimizing both technical and nontechnical losses in the electric grid and sharing the experience of the transformation part of Lebanon to smart metering. read more... read less...
Keywords: Water Treatment, geothermal energy, Smart Grids