**Abstract**

This Science article summarizes the preliminary work carried out by the Renewable Energy Development Centre under the National Research Project in the Central North of Algeria from 2013 to 2016 to explore for geothermal resources and hydrogeology and hydrogeochemical and therapeutic aspects. The geology is very complex in this region and it determines the thermal water reservoirs. The value and importance of the thermal springs in Algeria is very significant. This study will be addressed by means of conventional chemical analyzes of the main hot springs major elements in the north central region of Algeria. Hydrogeochemical prospecting was carried out in detail is briefly exposed and the main results are described in particular regarding the hot springs of the Centre North of Algeria. The existing geothermal potential in Algeria is operated primarily for the balneotherapy and some applications for aquaculture. In this study, we will apply the hydrogeochemical techniques to the hot springs of the Centre North of Algeria. To promote this energy source which will certainly have a socio-economic interest, it is important to know the geothermal gradient in this region and the hydrogeological and physico chemical characteristics of the main hot springs particularly temperature, flow rate and the elements major chemical. The thermal springs of north central Algeria belong to the Tellian domain, characterized by a complex geological structure and active tectonics. The thermal spring of Hammam Bouira is strongly mineralized, it presents a sodium chloride chemical facies. These facies are generally linked to Triassic evaporites. The thermal waters of the study area are characterized by a hyper mineralized facies (4 to 20 mS/cm at 25° C), sodium chloride type source Hammam Melouane and source Hammam Bouira. The mineralization of these thermal springs is acquired from contact with the evaporite formations of the Triassic, mainly by the dissolution of halite and gypsum. Known for its geological, structural and tectonic complexity, the northwestern region of Algeria has very important thermal manifestations. The presence of thermal springs in this region are linked to the existence of faults. Ten sources of spas were analyzed in the laboratory of the National Tourist Company in 1984. The chemical analysis of the major element concentrations (Ca2 +, Mg2 +, Na +, K +, Cl-, SO4 2-, HCO3 - and NO3 -) and the physico-chemical variables (temperature, electrical conductivity, dry residue and pH). The physico-chemical composition of warm waters in this region shows a very

## *Geothermal Energy*

varied chemical facies due to the complexity of geology. The geothermal applications are very diverse: - The balneology, aquaculture, heating greenhouses, air conditioning habitat and production of electricity. The use of geothermal energy helps to preserve natural resources while reducing CO2 emissions related to energy production and to cure certain diseases. Direct use of geothermal energy in agriculture, spas and domestic heating is possible.

**Keywords:** Hydrogeology, Hydrogeochemistry, Geothermal gradient, Therapeutic aspects, geothermal potential, low-energy, direct applications, health
