Ahmad Sakhrieh

Optimized cleaning and cooling for photovoltaic modules based on the output performance

This study aimed to design and implement a smart automatic cleaning and cooling system for photovoltaic modules to be activated based on power drop resulting from dust accumulation and high temperature conditions. This was tested by installing two side by side identical photovoltaic modules. The first module was equipped with the prototype cleaning system while the second one was considered as standard. An optimized cleaning and cooling procedure was adopted using data acquisition system. The operational performance of both panels was recorded and analyzed. An increase in energy yield of 8.7% was obtained as a result of minimizing the operational disturbances of dust accumulation and high surface temperature of the photovoltaic panel.

Performance of diesel engine using gas mixture with variable specific heats model

Abstract A thermodynamic, one-zone, zero-dimensional computational model for a diesel engine is established in which a working fluid consisting of various gas mixtures has been implemented. The results were compared to those which use air as the working fluid with variable specific heats. Most of the parameters that are important for compression ignition engines, such as equivalence ratio, engine speed, maximum temperature, gas pressure, brake mean effective pressure and cycle thermal efficiency, have been studied. Furthermore, the effect of boost pressure was studied using both the gas mixture and dependent temperature air models. It was found that the temperature dependent air model overestimates the maximum temperature and cylinder pressure. For example, for the air model, the maximum temperature and cylinder pressure were about 1775 K and 93·5 bar respectively at 2500 rev min−1, and the fuel/air equivalence ratio Φ = 0·6. On the other hand, when the gas mixture model is used under the same con...

A comparative analysis of energy indicators and CO2 emissions in 15 Arab countries

This study presents a comparative energy and emissions analysis of 15 Arab countries. The relation between energy consumption, CO2 emissions, Gross Domestic Product (GDP), and population is analysed in each of these countries through various energy and CO2 emission indicators: GDP Per Capita (GDPPC), TPES per capita (TPESPC), TPES/GDP, CO2/TPES, CO2 per capita and CO2/GDP. This study also analyses the final energy consumption in these countries according to the type of energy used in addition to its distribution in different sectors.

Two-dimensional numerical modeling of combustion of Jordanian oil shale

ABSTRACT A two-dimensional (2-D) modeling of the burning process of Jordanian oil shale in a circulating fluidized bed (CFB) burner was done in this study. The governing equations of continuity, momentum, energy, mass diffusion, and chemical combustion reactions kinetics were solved numerically using the finite volume method. The numerical solution was carried out using a high-resolution 2-D mesh to account for the solid and gaseous phases, k-ε turbulence, non-premixed combustion, and reacting CFD model with the same dimensions and materials of the experimental combustion burner used in this work. The temperature distribution and evolution of species were also computed. Proximate and ultimate analyses were also performed to evaluate the air–fuel ratio and ash content. The required thermophysical properties, such as heating value, density, and porosity were obtained experimentally, while the activation energy was obtained from published literature. It was found that the temperature contours of the combustion process showed that the adiabatic flame temperature was 1080 K in a vertical burner, while the obtained experimental results of maximum temperature at various locations of the burner in actual, non-adiabatic, non-stoichiometric combustion reached 950 K, showing good agreement with the model.

Combustion characteristics of solid waste biomass, oil shale, and coal

ABSTRACT In this study, a developed two-dimensional mathematical model was used to represent the physical model of the combustion process of olive cake and date seed, and solve the governing equations using finite-volume method. The simulation was performed using ANSYS/Fluent software in order to estimate maximum temperature, heating values and pollutants concentrations. The obtained results were compared with experimental results, and corresponding values of oil shale and coal. The experimental work of direct burning of olive cake and date seeds was performed using an existing circulated fluidized bed (CFB) unit. It was found that the adiabatic flame temperatures were 1380 K and 839 K for olive cake and date seed, and 2260 K and 1080 K for coal and oil shale, respectively. The experimental results showed that the maximum temperatures were 1126 K and 723 K for olive cake and date seed, respectively. The lower heating values were 19,500 kJ/kg and 16,400 kJ/kg for olive cake and date seed, and 29,000 kJ/kg and 7000 kJ/kg for coal and oil shale, respectively. Thus, biomass such as date seed and olive cake may be used as an alternative fuel in electrical power plants in olive- or date-producing countries, which may save 40% of fuel cost.

Enhancement of Thermal Energy Storage Using Phase-Change Material under Jordanian Climate

AbstractIn this paper, the effect of using a phase-change material (PCM) on the storage capacity of a conventional solar storage system was carried out. This was obtained by using encapsulated spheres that contain paraffin wax as PCM; this enables the control of the quantity of the PCM. The quantity of the solar energy stored was indicated by the rise in both inlet and outlet water temperatures of the collectors used in the system. Hourly storage temperatures were recorded during the charging of the system. The maximum increase in water temperature was recorded when the volume flow rate of the water was found to be 4  L/min; this value was used throughout the work to study the enhancement of thermal energy storage using PCM. It was found that the amount of energy stored increases with the quantity of phase-change material, with a percent increase in the inlet and outlet water temperatures of 8 and 9%, respectively.

A study on the Jordanian oil shale resources and utilization

Jordan has significant oil shale deposits occurring in 26 known localities. Geological surveys indicate that the existing deposits underlie more than 60% of Jordans territory. The resource consists of 40 to 70 billion tones of oil shale, which may be equivalent to more than 5 million tones of shale oil. Since the 1960s, Jordan has been investigating economical and environmental methods for utilizing oil shale. Due to its high organic content, is considered a suitable source of energy. This paper introduces a circulating fluidized bed combustor that simulates the behavior of full scale municipal oil shale combustors. The inside diameter of the combustor is 500 mm, the height is 3000 mm. The design of the CFB is presented. The main parameters which affect the combustion process are elucidated in the paper. The size of the laboratory scale fluidized bed reactor is 3 kW, which corresponds to a fuel-feeding rate of approximately 1.5 kg/h.

EXPERIMENTAL STUDY OF USING EMULSIFIED DIESEL FUEL ON THE PERFORMANCE AND POLLUTANTS EMITTED FROM FOUR STROKE WATER COOLED DIESEL ENGINE

A water‐cooled, four stroke, four cylinder, direct injection diesel engine was used to study the effect of emulsified diesel fuel on the engine performance and on the main pollutant emissions. Emulsified diesel fuels of 0%, 5%, 10%, 15%, 20%, 25% and 30% water by volume were used. The experiments were conducted in the speed range from 1000 to 3000 rpm. It was found that, in general, using emulsified fuel improves the engine performance and reduces emissions. While the BSFC has a minimum value at 5% water and 2000 rpm, the torque, the BMEP and efficiency are found to have maximum values under these conditions. CO2 was found to increase with engine speed and to decrease with water content. NOx produced from emulsified fuel is significantly less than that produced from pure diesel under the same conditions.

Electro-Hydrodynamic Control of Premixed Turbulent Methane Flames at Pressures Above 1 ATM

Electric field control of combustion offers the potential of stabilizing flames and reducing emissions with comparatively little effort. Previous investigations of the effects of electric fields on flames were restricted to atmospheric pressure and the question whether field effects persist at higher pressures remained open. In the present work effects of electric fields on flame behavior are established for pressures up to 10 bar without any indication that this should be an upper limit. Voltage-current measurements and optical emission spectroscopy gave clear evidence that at all experimental conditions under investigation electric field induced ionization and dissociation reactions were negligible with regard to the combustion process. Thus it is concluded that all observed effects are due to electro-hydrodynamic distortions of the gas flow caused by electrostatic forces acting on the ions generated in the reaction zones of the flames. The concentration of pollutants such as CO, NO and NO2 in the presence of an electric field depends on the ratio U/p of electrode voltage U and pressure p which implies that the electric field strength required to obtain a given effect increases linearly with pressure. In an electric field directed towards the burner CO emissions could be reduced by about 90%, irrespective of pressure. The decrease of CO was accompanied by an increase of NOx by about 20%. The electric power required for a CO reduction of 90% amounted to 0.1% of the thermal power. The improvement of the lean blow-off limit upon application of an electric field observed so far ranges from 1 to 3% and increases with pressure.Copyright