Investigation on the energy efficiency of a geo-sol adsorption heat transformer in the Algerian context

Abstract

The demand for energy is growing rapidly due to the industrial and socio-economic development experienced by many emerging countries including Algeria. Therefore, the use of renewable energy is a good alternative to fossil fuels. Renewable energies are very economical, permanently available and are environmentally friendly. This work concerns the study and numerical simulation analysis of a solar-geothermal adsorption heat transformer (AHT) using zeolite 13X/H2O as a couple adsorptive (adsorbent/adsorbate). The findings were presented and interpreted over two periods respectively for summer (July 15th) and winter (December 15th). A numerical simulation was carried out on TRNSYS which made it possible to analyze the influence of the parameters on the system, namely, the surface of the solar collector, the depth, the climate in Algerian cities (Sidi Bel Abbès, Algiers, Adrar), and soil conductivity (clay, sand and limestone) on the outlet temperature of the geo-solar system. Moreover, a second calculation code has been developed using energy and mass conservation equations as well as the Dubinin-Astakhov equation of state which considers the influence of various parameters on the (AHT) system such as the GEO-SOLAR system outlet temperature, the generation, adsorption and evaporation temperatures. The results showed that the solar collector surface type, the test period, the depth and nature of the soil have significant effects on the thermal behavior of the geo-solar combined system. The performance of the AHT system is proportional to the outlet and adsorption temperatures. Moreover, the COP_AHT ranged from 0.40 to 0.48 and from 0.30 to 0.38 for the COP_sys, unlike the evaporation temperature.