In this paper, the numerical results of the study on geothermal-air heat exchanger in dry areas of Algeria (Ghardaia region) were presented. Computational fluid dynamics equations were solved using our specific code compilated with Fortran. The outputs of the numerical calculations were compared and validated with the experimental results and the outputs of a commercial CFD code. In these conditions, our results present good agreements with an error not exceeding 2%. By using our numerical model, we have calculated the optimum length, the internal diameter, the air velocity of the pipe in winter and summer periods and have determined the optimum depth at different depths. The comparison of two types of pipes making material (PVC and PEHD) has taken into account the characteristics of the Ghardaia-Algeria region (specific heat capacity, density, thermal conductivity and temperature) of the soil. The obtained results proved that the chosen model gives a satisfactory agreement in all the studied variables.

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Among the renewable energies there is geothermal energy, conventional air conditioning has negative consequences on the environment, to have an economical and sustainable solution: the EAHE respond to this concern. In the current study, the study of the thermal performance of the earth-air heat exchanger (EAHE) has been completed. For the impact of transient heat transfer in the ground near the hose, the thermal saturation of the ground is well mentioned. In addition, the role of the burial depth of the EAHE system is also taken into account during this work. The suitable depth of the buried tubes was determined by implementing the thermo-physical properties of the soil of the studied site located in Ghardaïa (Algeria) by writing a specific program. A parametric investigation was accomplished the effects of the length and the diameter of the pipe, in addition the speed of the inlet air on the temperature of the outlet of the EAHE system in both cases PVC and HDPE material. The results showed that the optimal parameters in order to obtain a good performance for the studied EAHE: maximal value of pipe length, and minimal values of diameter pipe and air velocity 30 mm and 1.2 m/s respectively.

The electronic and ionic effective potential of a fully ionized hydrogen plasma containing an impurity of electric charge (+Z m e) are calculated in a two-component plasma model under semiclassical conditions using classical statistical mechanics with a regularized electron-ion interaction. These effective potentials are coupled in a system of nonlinear integral equations (or coupled differential equations), which is solved numerically with two methods, namely the fixed-point method and the Runge-Kutta method. The Baranger-Moser electric microfield distributions are calculated and compared with those from molecular dynamics simulation. Agreement between theory and simulation is satisfactory, in general. KEYWORDSeffective potential, electric microfield distribution, electron-ion coupling 1 Z m e 2 r ∕(1 − e −r∕ T )e −r∕ De , [4][5][6] where De is the Debye length and T is the thermal De Broglie wavelength. The impurity-ion interaction is taken as the Debye interaction.