14 research outputs found
Experimental and theoretical study of Parabolic trough collector (PTC) with a flat glass cover in the region of algerian sahara (Ouargla)
No full textOPPORTUNITES ET CHALLENGES DE LA PROMOTION DES ENERGIES RENOUVELABLES EN ALGERIE
No full textLe développement économique d’un pays ne peut se reposer que sur l’exploitation d’un seul type de source d’énergie, comme c’est le cas pour l’Algérie avec les énergies fossiles. Ces dernières ne peuvent être exploitées indéfiniment. Notre pays doit impérativement diversifier son bouquet énergétique, en exploitant les énergies renouvelables et notamment le solaire et l’éolien. A cet effet, une panoplie de loi et de textes ont été concoctés dans ce sens et des moyens financiers mis à disposition ; néanmoins ces engagements seront-ils suffisants pour aboutir à nos objectifs si on n’associe pas d’une façon sérieuse les ressources humaines. Toute la problématique est là
Architectural Design Strategies for Enhancement of Thermal and Energy Performance of PCMs-Embedded Envelope System for an Office Building in a Typical Arid Saharan Climate
No full textThe literature showed many studies that evaluated single or multiple Phase change materials (PCMs) layers in passive, active, or in hybrid configurations for building applications. However, little attention has been given to evaluating the energy performance of buildings when PCMs are used together with other passive design strategies. In this work, the energy performance of an office building in a typical arid Saharan climate is simulated using EnergyPlus when a PCMs-embedded envelope is implemented. The office building was analyzed without/with PCMs using various thicknesses. Results indicated that the annual electrical energy for heating, ventilation and air conditioning (HVAC) could be reduced between 3.54% and 6.18%, depending on the PCM thickness. The performance of the office building, including PCMs, was then simulated using two practical architectural design strategies, namely windows-to-wall ratio (WWR) and rezoning of the interior spaces. Outcomes revealed that the annual energy consumption for HVAC can be reduced from 10% to 15.5% and from 6.1% and 8.54% when WWR is reduced by half to three-quarters, and the perimeter zones are enlarged by one-third to two-thirds of the original space area, respectively. By combining both architectural design strategies and PCM, the annual electrical HVAC energy can be reduced between 12.08% and 15.69%, depending on the design configuration and PCM thickness. This design option provides additional benefits also since it reduces the vulnerability of increasing the lighting and fuel gas heating energy because more perimeter zones are exposed to daylighting and solar radiation, respectively
Computational modeling of the transport and electrochemical phenomena in solid oxide fuel cells
No full textAbstractA mathematical model for a planar solid oxide fuel cell (SOFC) was constructed. The chemical species, the temperature distribution and the cell performance were calculated using unit model with double channels of co-flow pattern. The governing equations for mass continuity, momentum conservation, energy conservation and species conservation were discretized with the finite volume method. The equations are implemented in FORTRAN language. The water production and the hydrogen in the anode were taken into consideration in the model. The effects of the anode thickness, the operating conditions and various losses on the calculated results were investigated. Parametric analyses showed that all temperatures decreased with increasing losses. Another important finding is that the anode thickness has significant effect on gases distribution, along the main flow channel. For gas flow rate of 80.10-8 m3 s−1, the peak power density was 37508Wm−2, which was about 7.5% higher than that of 80.10-9 m3 s−1 gas flow rate. The results of this paper provide better understanding on the coupled heat/mass transfer and electrochemical reaction phenomena in an SOFC. The model developed can serve as a useful tool for SOFC design optimizatio
Experimental performance characterization and economic efficiency of 16.28 kWp grid-tied PV systems in semi-arid climate
No full textThe study of the paper aims to present a solar power plant performances and economic benefits of 16.28 kWp grid-tied solar PV systems under the real outdoor conditions of Ghardaïa, located in semi-arid area of the Algeria desert. The main goal of this study is to investigate the effectiveness, suitability, feasibility and reliably of these plants on the level of desert areas and under the influence of harsh conditions (desert environment) in the first part. In the second part, the contribution of solar PV plant to conventional networks in the arid and semi-arid environment to assess the rate of integration. Based on experimental measurement data, the paper also shows economic benefits of three photovoltaic plants. It was found that from the first January to last August 2019, the total produced energy by all PV arrays was 171.422 MWh which supplied to the internal grid and while, the consumed energy by the URAER unit was 159,094 kWh. Approximately 10, 95 % of the 159,094 MWh energy consumed in the whole year is provided from the generated PV solar energy that is 17,422 MWh. The total energy fed to the internal grid has grown from 27 MWh in 05/04/2018 to a maximum of 67.28 MWh recorded in 31/10/2019. The rate of integration of solar energy by all PV arrays in the internal network of the URAER varied between 6, 60% in January and 22, 96% in April. The integration of this renewable energy generation into the local grid in the URAER unit considered satisfactory over this period of operation. From the first January to last August 2019, the cost of electrical energy produced by solar plants is 2090,64 euro(277706,68 Algerian dinars) while the cost of energy consumed by the Applied Research Unit in renewable energies is 4772,82 euro(664853,826 Algerian dinars)
Solar flat plate collector enhanced by two reflectors: optimum tilts of reflectors
Get PDFIntroduction. In some solar concentrating system applications, in which the incoming sunlight is augmented by using commercial flat plate reflectors placed on different sides of the planar collector, it is very important to choose the optimum tilts of boosters (attached edge-to-edge on the top and bottom sides of the solar collector) for each month, to enhance their received solar irradiation over the year in the southern Algeria. The novelty of the proposed work consists of the development of a novel mathematical model in which the reference of the reflector’s tilt angles is the collector plane, and optimal tilts are optimized on the average day of each month. Purpose. This paper proposes a novel analytical model of two identical planer reflectors, placed on the top and bottom of a latitude tilted flat plate solar collector, for optimizing their optimal inclination angles during the daytime throughout the year in Ouargla city, southeast of Algeria. Methods. Optimal tilt angles of reflectors were obtained by searching for the optimum captured solar irradiation on the collector’s surface from each reflector in the representative day of each month of the year. After that, the obtained tilts were used for calculating incoming solar irradiation on the received area and comparing them to the solar collector without reflectors. Results. The findings of this paper showed that the reflector’s inclination angles were variable from one month to another in which the upper reflector’s tilts reached its maximum in June and minimum in December, contrarily for the lower reflector. Again, an increase of 28.05 % in the daily received solar irradiation on the collector surface with reflectors compared to the conventional one.Вступ. У деяких сонячних концентруючих системах, в яких сонячне світло, що падає, посилюється за рахунок використання комерційних плоских відбивачів, розміщених по різні сторони плоского колектора, дуже важливо вибрати оптимальні нахили підсилювачів (прикріплених кромкою до кромки зверху). і нижні сторони сонячного колектора для кожного місяця, щоб збільшити одержуване ними сонячне випромінювання протягом року в південному Алжирі. Новизна запропонованої роботи полягає у розробці нової математичної моделі, в якій еталоном кутів нахилу рефлектора є площина колектора, а оптимальні нахили оптимізуються у середній день кожного місяця. Мета. У цій статті пропонується нова аналітична модель двох ідентичних плоских відбивачів, розміщених зверху та знизу плоского сонячного колектора з нахилом по широті, для оптимізації їх оптимальних кутів нахилу вдень протягом року у місті Уаргла, на південний схід від Алжиру. Методи. Оптимальні кути нахилу рефлекторів були отримані шляхом пошуку оптимального сонячного випромінювання на поверхню колектора від кожного рефлектора в репрезентативні дні кожного місяця року. Після цього отримані нахили використовувалися для розрахунку сонячної радіації на отриману площу і порівняння їх з сонячним колектором без відбивачів. Результати цієї статті показали, що кути нахилу рефлектора змінювалися від місяця до місяця, коли нахил верхнього рефлектора досягав максимуму в червні і мінімуму в грудні, на відміну від нижнього рефлектора. Знову ж таки, збільшення на 28,05 % щоденно одержуваного сонячного випромінювання на поверхню колектора з відбивачами порівняно зі звичайним
REVIEW ON THERMAL ENERGY STORAGE SYSTEMS
No full textIn the past five thousand years human energy consumption per capita has risen from 9 to 230 kWh/capita.day. At thecurrent rate of usage, taking into consideration population increases, natural resources will be depleted within a fewdecades. One must therefore endeavour to take precautions today for a viable world for coming generations. There aremany situations where available energy is wasted because it is in the wrong place and/or at the wrong time. Therefore, there is a desperate need for energy storage and a very wide range of techniques is used for this purpose. Most methods involve high capital investment; however, so a cheaper alternative has been widely exploited in whichthermal energy is stored in a suitable medium. Sensible and latent heat thermal storage systems in general have beenamong main topics in research for the last two decades or so, but although the information is quantitatively enormous, itis also widely spread in the literature, and often quite difficult to find. This work provides a survey of studies dealingwith thermal energy storage (TES) using sensible and solid–liquid phase change thermal energy storage units. Threeaspects have been the focus of this review: storage media, heat transfer analysis and applications. The work describedbelow falls within an area of international interest as it deals with energy saving, the efficient and rational useof available resources and the optimum use of renewable energies
POTENTIAL USE OF SMALL-SCALE DESALINATION UNITS IN REMOTE ARID LOCALITIES
No full textWater and energy are the two most fundamental ingredients of modern civilization. As the world’s population grows innumber and affluence, the demands for both resources are increasing faster than ever. According to the World HealthOrganization, approximately 2.4 billion people live in highly water-stressed areas. Reports on the availability of potablewater in Africa have listed Algeria among 17 African countries affected by water shortage. In theory, the current wateravailability per capita in Algeria is 500 m3, down from 1, 500 m3 in 1962. It is projected that it will further reduce to 450m3in 2020. Algeria abounds with natural resources such as oil and gas. However, Algeria is lacking in one veryessential resource: water. The lack of fresh water in different remote parts of Algeria hinders the development of thecommunities in these areas. Fortunately, the solar potential of Algeria ranks among the highest in the world. The annualsunshine duration reaches 2000 hrs all over the territory and 3900 hrs in the Sahara. The received energy is 1700 kWh/m2/year in the north, 1900 kWh// m2/year in high plains and 3000 kWh// m2/year in the Sahara. This makes solardistillation a feasible solution to the problem in these areas. Several techniques for sea water (brackish water)desalination are now in use. But solar distillation remains the most economic and effective technique for plants withsmall capacities, having low investment and operation costs. Considerable attention has recently been given to the useof solar energy in sea and brackish water distillation. The work described below falls within an area of internationalinterest as it deals with the optimum use of renewable energies. This work provides studies dealing with smallscale distillation for low-density population areas using solar energy
