National Energy and Water Research Center

Abu Dhabi, United Arab Emirates

National Energy and Water Research Center

Abu Dhabi, United Arab Emirates
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Al Jallad F.,National Energy and Water Research Center | Al Katheeri E.,National Energy and Water Research Center | Al Omar M.,National Energy and Water Research Center
Sustainable Environment Research | Year: 2013

In this study, data describing PM10 concentrations, atmospheric temperature, relative humidity and wind speed for 2007 to 2009 were analyzed and evaluated. The data were collected from an ambient air quality station in Al Samha, Abu Dhabi, United Arab Emirates. The variation patterns of PM10 concentrations were explored, and their relationships with meteorological parameters were identified. It was found that the studied area is characterized by low wind speeds, hot and humid conditions. Daily mass concentrations of PM10 ranged from 13 to 1526 μg m-3 with a mean value of 172 ± 196 μg m-3, and about 36% of days had concentrations above the national standard limit (150 μg m-3). High diurnal concentrations of PM10 were found to be associated with the traffic rush hours, with a primary peak occurring in the afternoon and a secondary peak occurring at 17:00. The highest level of PM10 was observed on Saturdays, while the lowest level was on Wednesdays. Dry seasons showed higher PM10 levels than those during wet seasons, where the maximum monthly average concentration of 517 ± 445 μg m-3 was recorded in June 2008, and the lowest value was 38 ± 28 μg m-3 recorded in December 2009. Pearson analysis revealed strong positive correlations between PM10 and temperature, low humidity and wind speed. Conversely, there was a strong inverse correlation between PM10 and relative humidity levels greater than 25%.


Al-Sabounchi A.,National Energy and Water Research Center | Gow J.,De Montfort University | Al-Akaidi M.,De Montfort University
IET Renewable Power Generation | Year: 2014

Unlike traditional distribution generation (DG) units, the production of photovoltaic DG (PVDG) units is nondispatchable and largely driven by the rates of solar irradiance fall on its PV array. In this work, a suitable procedure for optimal sizing and location of single PVDGs on radial distribution feeders has been developed. It goes along with the current trend of interfacing renewable energy generators with the grid due to global warming concern. The procedure applies single PVDG unit at points on the feeder while allowing reverse power flow (RPF) within the feeder line sections. The optimisation objective is to minimise the accumulated line power loss over the day (line energy loss) along the feeder, while keeping the voltage profile along the feeder within permissible limits. A method has been applied to rate the line energy loss considering one time interval, namely feasible optimisation interval. The procedure has been applied to an actual 11 kV feeder in Abu Dhabi city. The application showed obvious benefits in terms of line loss reduction and improvement of the voltage profile. The procedures also resulted in alternative feasible solutions in case the optimal solution cannot be applied for any reason - like inconvenience/limitation of land or investment. © The Institution of Engineering and Technology 2014.


Al-Sabounchi A.M.,National Energy and Water Research Center | Yalyali S.A.,National Energy and Water Research Center | Al-Thani H.A.,National Energy and Water Research Center
Renewable Energy | Year: 2013

A pilot photovoltaic (PV) grid-connected system rated at 36 kWp has been designed and installed at the 0.4 kV level of the Abu Dhabi distribution network. The performance of the system under the actual weather conditions has been evaluated in terms of power and energy production, conversion efficiency, consistency of voltage and frequency, along with the impact of ambient temperature. Additionally, the influence of accumulated dust deposition on the production of the PV array has been evaluated. The evaluation showed consistent operation of the system with a moderate conversion efficiency even with the high ambient temperatures at the site. However, the dust deposition on the glazing of PV modules was found to seriously degrade the performance of the PV system.The outcome of this work is deemed important in assisting accurate PV system design, and also in scheduling suitable cleaning cycles for the PV strings. In this regard, cleaning the strings on a monthly basis was found to give reasonable results. © 2012 Elsevier Ltd.


Al-Thani H.A.,National Energy and Water Research Center | Hasoon F.S.,National Energy and Water Research Center
Conference Record of the IEEE Photovoltaic Specialists Conference | Year: 2012

(In,Ga)2Se3 (IGS) thin films were deposited on Molybdenum (Mo) coated soda lime glass (Mo/SLG) substrates, using physical vapor deposition (PVD) technique, resembling only the first stage of the typical 3-stage growth process of CIGS thin film. The Mo thin films were sputtered on SLG substrates using DC planar magnetron sputtering at working gas (Ar) pressure that varies from 0.6 mT to 16 mT. The sputtering pressure of Mo thin films was varied in order to induce variations in the sputtered films' morphology and microstructure; as well as to subsequently induce variations in the rate of Na out-diffusion from SLG substrate. The IGS thin film deposition process was carried out with the same conditions of substrate temperature (Ts ∼ 400°C) and deposition rate that are required to accomplish the first stage of the complete typical 3-stage process of a CIGS thin film growth. To gain an understanding of the structural correlation between Mo and IGS films, and the effect of this correlation on Na out-diffusion process from SLG substrate. The Mo and IGS films' structures were examined by θ/2θ X-Ray Diffraction (XRD) characterization technique. Secondary-ion mass spectrometry (SIMS) was also applied to depth profile the Na, Se, and O in the IGS/Mo films. Whereas, the root-mean-square (RMS) surface roughness of both Mo and IGS films, was determined using Atomic Force Microscopy (AFM). © 2012 IEEE.


Phok S.,National Energy and Water Research Center | Al Wahshi F.S.,National Energy and Water Research Center | Al Baity S.M.,National Energy and Water Research Center | Abdulla Yalyali S.A.,National Energy and Water Research Center
Materials Research Society Symposium Proceedings | Year: 2014

Bismuth selenide (BixSey) films are deposited onto glass substrate using chemical bath deposition at room temperature. The reacting bath contained bismuth nitrate, triethanolamine and sodium selenosulfate as selenium (Se) source. Ammonium hydroxide is used to adjust the pH of the bath. The films deposited in solutions containing Se source solution of 10 ml and 15 ml are characterized by surface morphological, compositional and structural, properties. The optimum deposition time is about 3 hours for both solutions. Films deposited up to 24 hours in bath with 10 ml Se source solution had thickness ranging up to 232 nm. The deposition rate is found to increase up to 61 nm/h for 3-hour deposition. In the case of bath with 15 ml Se source solution, the film thickness ranged from 45 nm to 632 nm for 1-hour to 24-hour deposition, respectively; with a deposition rate increasing up to 123 nm/h for 3-hour deposition. Film roughness of about 6.6 nm to 22.8 nm is measured by atomic force microscope for films deposited in bath containing 10 mL Se source and 15 ml of Se source, respectively. Crack free layers are observed with randomly large plate-like particles on top of the layer for some films. The films with typical composition of Bi21.8Se78.2 are found to be rich in Se when deposited for 6 hours, whereas the composition of a film deposited in the same bath (10 mL Se source) for 3 hours is found at Bi 60.3Se39.6. Additionally, structural analysis performed by x-ray diffraction (XRD) did not reveal well-defined XRD patterns, which indicates that BixSey films were constituted mostly of nanocrystalline grains. Copyright © Materials Research Society 2014.


Al-Sabounchi A.M.,National Energy and Water Research Center | Al-Hammadi E.,National Energy and Water Research Center | Yalyali S.,National Energy and Water Research Center | Al-Thani H.A.,National Energy and Water Research Center
Renewable Energy | Year: 2013

Connection of utility-interactive PV generators at the distribution level, namely PV distributed generation (PVDG), could bring many benefits to the distribution network. However, deployment of PVDG systems, in any country, requires actual data on the performance of these systems under actual weather conditions. Additionally, it needs compliance with the electrical structure and regulations of the power distribution network in that country. Hence, applying PVDG technology in the UAE brings forth many considerations and this work aims at tackling potential technical ones. Among these is the role of daily load curve and PV production curve in determining feasible locations and capacities of PVDG systems. The analyses are based on existing case study feeders at the 11 kV level of Abu Dhabi distribution network. Accordingly, the work results in suitable recommendations on feasible locations of PVDG systems. Also it defines rational objectives and constraints for optimal sizing and location of such systems. The other consideration tackled in this work is the performance of PVDG systems in actual UAE weather conditions. Actual data from two pilot PVDG systems installed in Abu Dhabi are collected and analyzed. The production of PV array, consistency of voltage and frequency and the conversion efficiency of PV modules and inverters along with the impact of ambient temperature are considered. In the same connection, the influence of accumulated dust deposition on the production of PV array in UAE is also taken over in this work. © 2012 Elsevier Ltd.


Agashichev S.P.,National Energy and Water Research Center
Desalination and Water Treatment | Year: 2011

Model describing the impact of degree of membrane rejection on behavior of concentration profile has been proposed. The model is based on the following physical assumptions: (1) the fluid was assumed to be incompressible, continuous and isothermal with uniform density field under the steady-state (time-independent) conditions; (2) transverse velocity was approximated by parabolic profile. Proposed model can be used for analysis of behavior of concentration profile. It can be applied for analysis of performance characteristics of membrane processes and laboratory- scale data at variable values of the observed degree of rejection. Sets of calculated profiles at different membrane rejection and temperature are attached. © 2011 Desalination Publications. All rights reserved.


Helal A.M.,National Energy and Water Research Center | Al-Jafri A.,National Energy and Water Research Center | Al-Yafeai A.,National Energy and Water Research Center
Desalination | Year: 2012

This study investigates the possibility of capacity enhancement of two brine recycle-MSF (Multi-Stage Flash) plants. The first has a conventional design whereas in the other the distillate from the heat recovery section is diverted, after cooling, to the town water tank. Thus the distillate from the recovery section is prevented from successive re-flashing in the heat rejection section. Also the distillate corridor from the heat rejection section is removed and condensate from heat rejection stages is collected individually into a common header after flashing and cooling to form a second product stream. Both plants incorporate a nanofiltration unit for the partial removal of bivalent scale forming ions from the makeup stream to enable operation at elevated TBT. Under the same operating conditions, it was found that the modified design exceeds the conventional one only by about 2% increase in distillate capacity. At the maximum recycle rate, 85% of the maximum recycle pump capacity, the increase in top brine temperature from 110. °C to 130. °C results in product capacity increase of 49.1 and 49.74% for the conventional and modified plants respectively. In many instances it was necessary to install additional pumping capacity to one or more of the process streams. © 2012 Elsevier B.V.


Al-Sabounchi A.,De Montfort University | Al-Sabounchi A.,National Energy and Water Research Center | Gow J.,De Montfort University | Al-Akaidi M.,De Montfort University | Al-Thani H.,National Energy and Water Research Center
2011 IEEE Electrical Power and Energy Conference, EPEC 2011 | Year: 2011

A suitable procedure for optimal sizing and location of a single Photovoltaic Distributed Generation (PVDG) unit on three-phase unbalanced radial distribution feeder has been developed. The procedure avoids reverse power flow along the feeder. It considers the peak mismatch of the feeder load curve and the PVDG production curve. With such mismatch, the PVDG system can produce only part of its capacity at the time the feeder meets its peak demand. Hence, solving the optimization problem for maximum line peak power loss reduction could make no sense. Alternatively, minimization of the accumulated line power losses over the day (line energy loss) is more appropriate in this application. A suitable derivation has been developed to rate the line energy loss reduction considering only one time interval, namely Feasible Optimization Interval (FOI). Thus, the optimization procedure can be solved for maximum line energy-based benefits considering only the FOI. This avoids running the calculations for each time interval over the whole duration. The procedure has been applied successfully on two 11kV feeders within the Abu Dhabi Distribution network. © 2011 IEEE.


Al Jallad F.,National Energy and Water Research Center | Al Katheeri E.,National Energy and Water Research Center | Al Omar M.,National Energy and Water Research Center
WIT Transactions on Ecology and the Environment | Year: 2013

Levels of particulate matter and meteorological variables (atmospheric temperature, relative humidity and wind speed) for 2009 to 2011were analyzed and evaluated. Data used in this paper were obtained from an ambient air quality station located in the western desert of Abu Dhabi Emirate-United Arab Emirates. The variation patterns of PM10 concentrations were explored, and their relationships with meteorological parameters were identified. The study area is characterized by relatively low wind speed, high temperatures and humidity and elevated levels of suspended particle concentrations. Hourly levels of PM10 were found to range between 4 to 3474μg/m3 with 27% of the daily average values exceeding the national standard limit of 150μg/m3. The diurnal variation pattern of PM10 showed two concentration peaks, the first of which occurred in the afternoon whereas the second peak occurred at 16:00. The highest level of PM10 was observed on Tuesdays, while the lowest level was on Fridays. The highest main value of PM10 was observed on July where a level of 204μg/m3 was reported and lowest level of 47μg/m3 was reported in January. Pearson's analysis revealed a positive correlation between PM10 and temperature, low humidity (≤13%) and wind speed conditions. On the other hand, a strong inverse relationship was observed between PM10 concentrations and relative humidity higher than 13%. © 2013 WIT Press.

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