Fahad A. Al-Sulaiman

Applications of wind power on the east coast of Saudi Arabia

Assessment of wind power on the east coast of Saudi Arabia has been made. A comparison between the wind and solar power shows that the mean attainable wind power is 70.6 W/m2, while the mean attainable solar power is 500 W/m2. However, the mean producible wind power is about 50 W/m2—using Cp = 0.42, while the mean producible solar power through photovoltaic cells is 90 W/m2 (using 18% efficiency). The availability of wind power in this area is 55% while the availability of solar power is 39%. The use of shrouded walls to improve the performance of WEC is feasible due to the narrow band wind direction, (280° to 30°).

Effects of weathering on failure pressure of filament-wound GFRP thermoset pipes:

Burst tests have been performed on the glass fiber-reinforced (GFR) thermoset pipes before and after exposure to natural and accelerated environmental conditions. The main objective of this study was to explore the effects of long-term natural outdoor and artificial accelerated environmental conditions on the burst resistance of the vinyl-based and epoxy-based GFR filament wound thermoset pipes which are targeted for use in crude oil transportation. The pipes were exposed to natural outdoor and accelerated dry heat conditions. The results show that these environments did not produce any noticeable degradation in the hydrostatic burst resistance of the pipes up to 24 months of natural exposure and up to 10,000 h of dry heat exposure.

Surface Characteristics of Silicon Nanowires/Nanowalls Subjected to Octadecyltrichlorosilane Deposition and n-octadecane Coating

In this study, nanowires/nanowalls were generated on a silicon wafer through a chemical etching method. Octadecyltrichlorosilane (OTS) was deposited onto the nanowire/nanowall surfaces to alter their hydrophobicity. The hydrophobic characteristics of the surfaces were further modified via a 1.5-μm-thick layer of n-octadecane coating on the OTS-deposited surface. The hydrophobic characteristics of the resulting surfaces were assessed using the sessile water droplet method. Scratch and ultraviolet (UV)-visible reflectivity tests were conducted to measure the friction coefficient and reflectivity of the surfaces. The nanowires formed were normal to the surface and uniformly extended 10.5 μm to the wafer surface. The OTS coating enhanced the hydrophobic state of the surface, and the water contact angle increased from 27° to 165°. The n-octadecane coating formed on the OTS-deposited nanowires/nanowalls altered the hydrophobic state of the surface. This study provides the first demonstration that the surface wetting characteristics change from hydrophobic to hydrophilic after melting of the n-octadecane coating. In addition, this change is reversible; i.e., the hydrophilic surface becomes hydrophobic after the n-octadecane coating solidifies at the surface, and the process again occurs in the opposite direction after the n-octadecane coating melts.

Silicone oil impregnated nano silica modified glass surface and influence of environmental dust particles on optical transmittance

The behavior of environmental dust particles on a silicone oil impregnated glass surface is examined in relation to optical transparent surfaces for self-cleaning applications. The characteristics of environmental dust, collected in the local area, are analyzed using analytical tools. Functional silica particles are synthesized and deposited on the glass surface prior to silicone oil impregnation. Optical properties of functionalized silica particle deposited glass surfaces are examined prior to and after oil impregnation. Further tests are conducted in the open environment to assess dust settlement in silicone oil and dust particle sedimentation on the glass surface. It is found that dust particles have various sizes and shapes, and they are composed of various metallic, alkaline, and alkaline earth metallic compounds. The average size of the dust particles is of the order of 1.2 μm. Silicone oil impregnation considerably improves the optical transmittance of functionalized silica particle deposited glass. A high spreading rate gives rise to a cloaking of dust particles on the oil surface, which gradually reduces the surface tension force and modifies the vertical force balance. Consequently, dust particles immerse into the oil film and sediment on the glass surface. This, in turn, lowers the optical transmittance of the oil impregnated glass surfaces greatly.

Energy and Exergy Analyses of an Air Membrane Heat and Mass Exchanger for Air Conditioning Applications

AbstractA comparison of energy and exergy analyses for an air conditioning system with and without an air membrane heat and mass exchanger was performed. The study considered several key performanc...

Nanowires: a new pathway to nanotechnology-based applications

AbstractThe synthesis and the characterisation of silicon nanowires (SiNWs) have recently attracted great attention due to their potential applications in electronics and photonics. As yet, there are no practical uses of nanowires, except for research purposes, but certain properties and characteristics of nanowires look very promising for the future. Graphical abstractSemiconductor nanowires are attracting more and more interest for their applications in nanoscience and nanotechnology. The characteristic of the nanowires is their geometry with a diameter in the range of a few nanometers and a length far greater than their diameter. The structural defects often lead to mechanical defects. By reducing the number of defects per unit length, decreasing the lateral dimensions, crystalline nanowires are expected to be more resistant than the solid. Recently nanowires are attracting intense interest for solar energy conversion. In this review, we summarize the different methods of nanowires production and their applications. Special focus will be kept on silicon nanowires.

Fabrication and optical simulation of vertically aligned silicon nanowires

Silicon nanowires (Si-NWs) have been considered widely as a perfect light absorber with strong evidence of enhanced optical functionalities. Here we report finite-difference time-domain simulations for Si-NWs to elucidate the key factors that determine enhanced light absorption, energy flow behavior, electric field profile, and excitons generation rate distribution. To avoid further complexity, a single Si-NW of cylindrical shape was modeled on c-Si and optimized to elucidate the aforementioned characteristics. Light absorption and energy flow distribution confirmed that Si-NW facilitates to confine photon absorption of several orders of enhancement whereas the energy flow is also distributed along the wire itself. With reference to electric field and excitons generation distribution it was revealed that Si-NW possesses the sites of strongest field distributions compared to those of flat silicon wafer. To realize the potential of Si-NWs-based thin film solar cell, a simple process was adopted to acquire vertically aligned Si-NWs grown on c-Si wafer. Further topographic characterizations were conducted through scanning electron microscope and tunneling electron microscope-coupled energy-dispersive spectroscopy.

Techno-economic evaluation of different types of solar collectors for water heating application in domestic sector of Saudi Arabia

Electric water heaters consumes major part of energy in residential sector and hence there is a need to find an economical solution. One potential solution is to use solar water heating (SWH) systems. The aim of this work is to assess the techno-economic viability of SWH technologies for domestic purpose. In this study, different types of SWH collectors like evacuated tube and glazed collectors are simulated using RETScreen software whose credibility is widely accepted for calculating energy production, life cycle assessment, greenhouse gas emissions, and fuel savings for SWH applications. Calculations are performed to obtain at least 50 % solar fraction on the basis of number of SWH collectors. Other considerations involve collectors types, slope angle, tracking mode, collector thermal loses, collector optical efficiency, and back up fuel which is electricity in our case. Simulations are performed for five different cities of Saudi Arabia. Choices are being made to cover different geographical coordinates of the kingdom that involve Jeddah (western coast), Dhahran (eastern coast), Tabuk (north), Riyadh (center), and Bisha (south). Simulated results based on solar radiations on the horizontal and tilted surface, solar fraction, greenhouse gas emissions, and energy savings are used for comparative analysis of different types of solar collectors while net present value, payback period, benefit to cost ratio, and annual life cycle savings are the deciding factors for economic viability of these systems. Results indicate that under same prevailing conditions Bisha is the most attractive while Tabuk is the least suitable place for solar SWH technology.

Global solar radiation and energy yield estimation from photovoltaic power plants for small loads

ABSTRACT Daily global solar radiation on a horizontal surface and duration of sunshine hours have been determined experimentally for five meteorological stations in Saudi Arabia, namely, Abha, Al-Ahsa, Al-Jouf, Al-Qaisumah, and Wadi Al-Dawaser sites. Five-years of data covering 1998–2002 period have been used. Suitable Angstrom models have been developed for the global solar radiation estimation as a function of the sunshine duration for each respective sites. Daily averages of monthly solar PV power outputs have been determined using the Angstrom models developed. The effect of the PV cell temperature on the PV efficiency has been considered in calculating the PV power output. The annual average PV output energy has been discussed in all five sites for small loads. The minimum and maximum monthly average values of the daily global solar radiation are found to be 12.09 MJ/m2/d and 30.42 MJ/m2/d for Al-Qaisumah and Al-Jouf in the months of December June, respectively. Minimum monthly average sunshine hours of 5.89 hr were observed in Al-Qaisumah in December while a maximum of 12.92 hr in Al-Jouf in the month of June. Shortest range of sunshine hours of 7.33–10.12 hr was recorded at Abha station. Minimum monthly average Solar PV power of 1.59 MJ/m2/day was obtained at Al-Qaisumah in the month of December and a maximum of 3.39 MJ/m2/day at Al-Jouf in June. The annual PV energy output was found to be 276.04 kWh/m2, 257.36 kWh/m2, 256.75 kWh/m2, 245.44 kWh/m2, and 270.95 kWh/m2 at Abha, Al-Ahsa, Al-Jouf, Al-Qaisumah, and Wadi Al-Dawaser stations, respectively. It is found that the Abha site yields the highest solar PV energy among the five sites considered.

Transparent Conductive Oxide Films for High-Performance Dye-Sensitized Solar Cells

In this paper, atmospheric pressure chemical vapor deposition of fluorine-doped tin oxide (FTO) thin films of various thicknesses and dopant levels is reported. The deposited coatings are used to fabricate dye-sensitized solar cells, which exhibited reproducible power conversion efficiencies in excess of 10%. No surface texturing of FTOs or any additional treatment of dye-covered films is applied. In comparison, the use of commercial FTOs showed a lower cell efficiency of 7.11%. Detailed analysis showed that the cell efficiencies do not simply depend on the resistivity of FTOs but instead rely on a combination of carrier concentration, thickness, and surface roughness properties.