Annexes.

In the present work of this thesis, experimentally and modeling investigations of the effect of mass flow rate on the performance of a Helicoidal Water Air Heat Exchanger (HWAHE) in the region of El-Oued (south-east of Algeria), were undergone. On the basis of the obtained results, an experimental study of the refreshing strategy (HWAHE) system in the El Oued region, it was shown that a great potential of the earth to air heat exchanger technique for buildings and agricultural greenhouses in arid regions preheating or precooling may be ensured. The HWAHE made of PVC piping with 30 m of length and 0.06 m of diameter was immersed into the bottom of a water well at 5 m depth. In addition, a theoretical model was developed to determine the evolution of the air temperature inside the HWAHE as function of the main operating parameters. It is found that the exchanger is mainly depending on the mass flow rate. As results, the maximum heat exchange reached nearly 418 W at 0.035 kg. s?1 of mass flow rate while the maximum of temperature gap between the inlet and the outlet air was 14.1 o C. The HWAHE efficiency decreased with the increase of the mass flow rate. The efficiency of heat exchanger was obtained to be 82%, 81% and 80% for the average velocity value of 0.035, 0.05 and 0.07 kg. s?1, respectively. In addition, exergitical and economical investigate were carried out. The HWAHE energy and exergy efficiencies are maximal, and they reach to 92% and 89%, respectively.