volume-07-Issue 1 (2014)
Heat Transfer Enhancement by Using Porous Heat Exchangers
IJTEE, volume-07, Issue 1 (2014) , PP 51 - 54
Published: 15 Jul 2014
by Mohammadreza Azimi, Mojtaba Aghajani Delavar from Faculty of Engineering, Aerospace Group, Tarbiat Modares University, Tehran, Iran, 14115-111 Department of Mechanical Engineering, Babol University of Technology, Babol, Iran, 47148-71167
Abstract: Effective heat transfer is essential in a variety of energy technologies in order to enable the maximum possible power density and power conversion efficiency needed for economic competitiveness and fuel conservation. The goal of enhanced heat transfer is to encourage or accommodate high heat fluxes. This results in a reduction of heat exchanger size, which generally leads to less capital cost. Recently tremendous works have been conducted on heat transfer enhancement and a large number of techniques for heat transfer enhancement have been developed. This work concerns the investigation of the effect of porous media on heat transfer rate in heat exchangers. read more... read less...
Keywords: Heat transfer enhancement, Porous heat exchanger, Porous material, Heat exchanger.
Reduction a Particulate Matter of Diesel Emission by the Use of Several Oxygenated Diesel Blend Fuels
IJTEE, volume-07, Issue 1 (2014) , PP 45 - 50
Published: 16 Apr 2014
by Ali Alahmer from Department of Mechanical Engineering, Tafila Technical University, Tafila, Jordan, P. O. Box 179, 66110
Abstract: Oxygenated diesel fuel blends have a prospective effectiveness to reduce a particulate matter (PM) emissions and powerfully to be an effective alternative instead of diesel fuel. This manuscript investigates the emission characteristics of four combinations of oxygenated diesel fuel blends in terms of ethanol, TGME, Glyme and Diglyme. Two blended fuels containing 5% and 15 % by volume for each oxygenated additive were prepared. Pure diesel fuel was used as a base fuel for all oxygenated diesel blends. The experiments were conducted using four cylinders, four stroke compression ignition Toyota Hilux Pickup of engine capacity (2494 cc) model 2006, inline DOHC 16 Valve. The experimental results showed that (i) the higher engine speed is produced lower PM emissions; (ii) the PM emitted by all the oxygenated diesel blends is significantly lower than of the corresponding pure diesel fuel; (iii) the increase of oxygenated percentage in the diesel blends, the PM emission decreases; (iv) A maximum and minimum of PM reduction was occurred when the engine fueled by 15 % by volume for ethanol and by 5 % by volume for TGME respectively. read more... read less...
Keywords: Diesel, emission, oxygenated additive, particulate matter, ethanol, Glyme, Diglyme
Towards a Clean and Sustainable Distributed Energy: The Potential of Integrated PEMFC-CHP
IJTEE, volume-07, Issue 1 (2014) , PP 33 - 44
Published: 15 Apr 2014
by I. Aleknaviciute, T. G. Karayiannis, M. W. Collins and C. Xanthos from School of Engineering and Design, Brunel University, London, Uxbridge, Middlesex, UB8 3PH, UK
Abstract: The use of fossil fuels within the current infrastructure for domestic energy supply is one of the main causes of anthropogenic emissions. The mitigation options to meet the ambitious carbon reduction targets set by the UK government are discussed in this paper, including the use of carbon capture and storage technology, clean renewable energy integration and a proposed system of integrated fuel cell combined heat and power (FC-CHP) technology. Analysis shows that the use of carbon capture and storage (CCS) technology within the current infrastructure can abate half the electricity associated CO2 emissions; however, this comes at a high cost penalty. The emissions associated with domestic heat cannot be prevented without changes in the energy infrastructure. Hydrogen powered fuel cells can provide clean energy at a range of scales and high efficiencies, especially when employed with a CHP system. However, production of CO2 free hydrogen is essential for fuel cell technology to contribute substantially to a low carbon economy globally. In this work three methods were investigated for small scale distributed hydrogen production, namely steam methane reforming, water electrolysis and cold plasma jet. The criteria used for comparisons include the associated CO2 emissions and the cost of energy production. Cold plasma jet decomposition of methane shows a high potential when combined with integrated FC-CHP technology for economically viable and CO2 free generation of energy, especially in comparison to water electrolysis. Including the value of the solid carbon product makes the plasma system most attractive economically. read more... read less...
Keywords: Clean energy, Hydrogen generation, Cold plasma jet
Analysis of Ocean Thermal Energy Conversion Power Plant using Isobutane as the Working Fluid
IJTEE, volume-07, Issue 1 (2014) , PP 25 - 32
Published: 12 Aug 2014
by A. Alkhalidi, M. Qandil, H. Qandil from Department of Energy Engineering, German Jordanian University, Amman, 11180 Jordan, Mechanical Engineering Department, Hashemite University, Zarqa, Jordan, Field Engineer at Schlumberger, Mumbai, India
Abstract: The use of organic isobutane will be investigated for a closed-cycle Ocean Thermal Energy Conversion (OTEC) onshore plant that delivers 110 MW electric powers. This paper will cover concept, process, energy calculations, cost factoids and environmental aspects. In isobutane cycle, hot ocean surface water is used to vaporize and to superheat isobutane in a heat exchanger. Isobutane vapor then expands through a turbine to generate useful power. The exhaust vapor is condensed afterwards, using the cold deeper ocean water, and pumped to a heat exchanger to complete a cycle. Results show the major design characteristics and equipment's of the OTEC plant along with cycle efficiency and cycle improvement techniques. read more... read less...
Keywords: Ocean Thermal Engineering Conversion (OTEC), isobutene, thermal plant, energy convergence.
Portable Solar Charger with Controlled Charging Current for Mobile Phone Devices
IJTEE, volume-07, Issue 1 (2014) , PP 17 - 24
Published: 15 Apr 2014
by Hussain A. Attia, Beza Negash Getu, Hasan Ghadban, Ahmed K. Abu Mustafa from Electronics and Communications Engineering Department, American University of Ras Al Khaimah, UAE
Abstract: In this paper, we design, construct as well as test and analyze an electronic circuit that can be used as a solar portable charger for mobile phone devices using the solar energy as a source of electric power. A suitable small size solar cell panel is selected that is easy to carry to any locations farther from city electric grids. The alternative use of the solar energy as power source is helpful in outdoor emergency situations and avoids the traditional way of waiting beside an electrical sockets or outlets for charging. We suggest here a special electronic design and construction with an important merit related to controlling battery charging currents. Software verification and simulations, laboratory experiments on the circuit, practical testing to the charging capabilities; all these are discussed in this paper. read more... read less...
Keywords: Solar power, photovoltaic, solar panel, mobile phone, portable charger, mobile battery, charging current
Heat Transfer Enhancement of Forced Convection in Horizontal Channel with Heated Block due to Oscillation of Incoming Flow
IJTEE, volume-07, Issue 1 (2014) , PP 11 - 16
Published: 15 Apr 2014
by Abdelouahab Bouttout, Smail Benissaad, Farid Berrahil from Laboratoire d’Energétique Appliquée et de Pollution, Département de Génie Mécanique, Université Mentouri Constantine, Route d’Ain El. Bey, Constantine 25000, Algérie, Algeria
Abstract: The study in question consists to amplify the hydrodynamic and thermal instabilities by imposed pulsation during forced convection of air cooling of nine identical heated blocks simulate electronic components mounted on horizontal channel. The finite volume method has been used to solve the governing equations of unsteady forced convection. This approach uses control volume for velocities that are staggered with respect to those for temperature and pressure. The numerical procedure called SIMPLER is used to handle the pressure-velocity coupling. The results show that the time averaged Nusselt number for each heated block depends on the pulsation frequencies and is always larger than in the steady-state case. The new feature in this work is that we obtained a short band of frequencies which the enhancement of heat transfer of all electronic components is greater than 20 % compared with steady non pulsation flow. In addition, the gain in heat transfer Emax attainted the maximum value for the central blocks. Our numerical results were compared with other investigations and found to agree well with experimental data. read more... read less...
Keywords: Hydrodynamic, Convective Heat Transfer, Oscillation in Fluid Flow
Electronically Controlled Expansion Valve for Use in a Geothermal Heat Pump System
IJTEE, volume-07, Issue 1 (2014) , PP 1 - 10
Published: 01 Jul 2014
by H. I. Abu-Mulaweh, D. W. Mueller, H. Oloomi from Department of Mechanical Engineering, Purdue University at Fort Wayne, IN, 46805, USA b Department of Electrical Engineering, Purdue University at Fort Wayne, IN, 46805, USA
Abstract: This paper presents a detailed design of a development control board that can control an electronic expansion valve in a geothermal heat pump. The design utilized a microcontroller based system with a fuzzy control algorithm, and a temperature and pressure sensor configuration at the inlet of the compressor. The fuzzy control was designed and simulated using Simulink in Matlab. The control algorithm takes the information that the microcontroller obtained from the pressure and temperature sensor and adjusts the valve accordingly to control the amount of superheat. The controller was able to bring the superheat to the desired set point of 10°F ±2°F and maintain it. read more... read less...
Keywords: Expansion valve, Geothermal, Electronic control, Heat pump