Fathi M.,Solar Equipments Unit UDES |
Chikouche A.,Solar Equipments Unit UDES |
Abderrazak M.,Solar Equipments Unit UDES
Energy Procedia | Year: 2011
The use of white LEDs in photovoltaic standalone lighting systems requires knowledge of electrical, optical and thermal characteristics. These parameters allow us to improve and develop this type of system. Luminous intensity and life time of LEDs components are functions of the current intensity. To have stable LEDs characteristics various configurations are proposed for the Driver circuit (Direct Current "DC" mode, Pulse Width Modulation "PWM" mode). Various selection criteria are discussed such as: the simplicity of the circuit, the cost of manufacturing, energy consumption and losses (thermal and electrical) generated by this specific LED's Driver. This study allowed us to implement a command control (DC Driver) to solar LEDs lamp based on white diodes of phosphorus GaN semiconductors. This system is applied to street lighting by means of photovoltaic standalone system. The aim of this work is to obtain a stable LEDs control command by using a minimum of electric power for operation with long service life and stable illumination. © 2010 Published by Elsevier Ltd.
Laidi M.,Solar Equipments Unit UDES |
Laidi M.,Dr. Yahia Fares University Center of Médéa |
Hanini S.,Dr. Yahia Fares University Center of Médéa |
Abbad B.,Solar Equipments Unit UDES |
And 4 more authors.
Journal of Renewable and Sustainable Energy | Year: 2012
This paper describes the design and development stages followed to convert a conventional vapour compression refrigerator to a solar powered one. A conventional refrigerator ENIEM 160 l was chosen and some changes were introduced on it to reduce the cooling load and consequently the power it required. Three prototypes were designed and tested; AC (alternative current) electrical power drives the first one using a converter, the Danfoss compressor that works with DC (direct current) was set up in the second, and BDF35 with Eutectic evaporator AC15 were used in the third refrigerator. The hermetic compressor was switched on and off to maintain an average inside air temperature between a maximum and minimum air temperature established by the thermostat. Many tests were carried out over 1 yr to study the performance of each of the refrigerators components and especially the compressor, the eutectic evaporator, as well as the system as a whole. These prototypes were installed and tested in Algeria, in two different climate types: mild, along the Mediterranean coast, and arid, in the Sahara. The data gathered as well as the analysis processes enabled our team to evaluate pertinent system components and optimize the equipment to specific environments and load requirements. It can be concluded that the performance of the eutectic refrigerator is very stable and it can serve for perishable food storage, vaccine, and drug depositing at low temperatures in remote areas using half energy and a low number of battery. © 2012 American Institute of Physics.
Fathi M.,Solar Equipments Unit UDES |
Mougas A.,Solar Equipments Unit UDES
Journal of Renewable and Sustainable Energy | Year: 2011
With the rapid development of silicon photovoltaic power generation systems in recent years, the silicon wafer material becomes more and more expensive. Large quantities of defective solar cells are rejected from production lines. By this study, we explore the methods for reusing silicon wafers of defective solar cells using metal insulator semiconductor (MIS) technology. For this, the insulating layers and the electrically conductive contacts must be totally etched. Also, we have to assure the removal of all alkali metal ions. In order to provide new operating MIS solar cells, we have deposited new layers into the etched silicon base material. These recycled wafers are chemically polished beforehand to remove all impurities and defects. Optionally, the layers to be stripped off can be etched selectively. We have applied hot phosphoric (H 3 PO4) acidic solution for MIS solar cells delayering. To permit a time-saving process, H3 PO4 solution is heated at temperature around 120 °C. By using this process, all insulating and contact layers are stripped off. © 2011 American Institute of Physics.