Browsing by Author "Abdelmalek Atia"

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A State of the Art : Heat Transfer within a MOSFET System
(university Of Eloued جامعة الوادي, 2020-02-23) Oussama Zobiri; Abdelmalek Atia
The FET (field effect transistor) is the backbone of today's semiconductor electronics. The Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is the most popular type of isolated gate FET used in a variety of electronic circuits. In recent years, the MOSFET miniaturization has gained considerable interest. As the size of the device decreases ( nano-scale) , the heat generated influences the efficiency of the device. There have been many thermal studies to improve the operation of the device. This paper gives an idea on the MOSFET and heat transfer phenomena within it.
Experimental and numerical analysis of helical geothermal heat exchanger operating in hot climates
(university Of Eloued جامعة الوادي, 2020-02-23) Nacer Lebbihiat; Abdelmalek Atia; Noureddine Meneceur
With the onset of the warm and cold season, the temperature inside the building goes far away from the human comfort condition, the geothermal heat exchanger systems can be used to refresh the buildings. various configurations especially single U-tube ground heat exchangers have been studied to improve the thermal performance of ground heat exchangers. Although helical type has better thermal performance than the others. The present paper provides experimental and numerical analysis of helical geothermal heat exchanger tested in El-Oued region (Algeria). A PVC pipe was used as a Helicoidally Water-Air Heat Exchanger (HWAHE), with 30 m of length and 0.6 m of diameter. The HWAHE was emerged in the bottom of water well of 5 m of depth. A mathematical model was developed to test thermal efficiency of the system and a parametric analysis was carried out taking into account the length and the radius of the pipe and the velocity of the air in the pipe. The results of performance show that the inlet air temperature has significant effect mainly when the difference in temperature between the ambient air and the water borehole increases. Therefore, the gained temperature gap between the inlet and the outlet air of the exchanger increases with the increasing of air inlet temperature. However, at air velocity of 10 m/s the efficiency of the exchanger reached 89%.
Experimental and numerical analysis of helical geothermal heat exchanger operating in hot climates
(university Of Eloued جامعة الوادي, 2020-02-23) Nacer Lebbihiat; Abdelmalek Atia; Noureddine Meneceur
With the onset of the warm and cold season, the temperature inside the building goes far away from the human comfort condition, the geothermal heat exchanger systems can be used to refresh the buildings. various configurations especially single U-tube ground heat exchangers have been studied to improve the thermal performance of ground heat exchangers. Although helical type has better thermal performance than the others. The present paper provides experimental and numerical analysis of helical geothermal heat exchanger tested in El-Oued region (Algeria). A PVC pipe was used as a Helicoidally Water-Air Heat Exchanger (HWAHE), with 30 m of length and 0.6 m of diameter. The HWAHE was emerged in the bottom of water well of 5 m of depth. A mathematical model was developed to test thermal efficiency of the system and a parametric analysis was carried out taking into account the length and the radius of the pipe and the velocity of the air in the pipe. The results of performance show that the inlet air temperature has significant effect mainly when the difference in temperature between the ambient air and the water borehole increases. Therefore, the gained temperature gap between the inlet and the outlet air of the exchanger increases with the increasing of air inlet temperature. However, at air velocity of 10 m/s the efficiency of the exchanger reached 89%.
Influence of parameters on performance of earth air heat exchanger in arid and hot climate
(university Of Eloued جامعة الوادي, 2020-02-23) Abdessamia Hadjadj; Abdelmalek Atia; Boubaker Benhaoua; Abderrahmane Khechekhouche
This paper presents a study influence parameter on the performance of an earth air heat exchanger (EAHE) in arid and hot climate. The effect of velocity, length and drop in temperature of the air is studied at the inlet and outlet of the pipe. The results show that maximum temperature drop available at low velocities because air gets larger time to get heat transfer in the underground pipe in soil and also the greater length of the pipe of earth air heat exchanger has more effect on performance of earth air heat exchanger. The temperature drops of air increases with decrease in air velocity, as in this study the temperature drop is 7.9 °C corresponding to 10 m/s velocities and 4.9 °C corresponding to 20 m/s velocities.