Feasibility Study of New Geothermal System for Heating Premises and Thermal Complexes: Experimental Investigation of Water-Air Heat Exchanger in the East of Algeria

Abstract

Abstract This paper constitutes a new technological solution for the exploitation of one of the most important geothermal deposits located in the locality of Biskra (South-east Algeria). This is the Albian aquifer whose hot waters from boreholes, hot springs and spas are poorly exploited while ambient temperatures during winter periods reach very low levels, especially at night. The principle of this geothermal system is to immerse a PVC tubular water-air exchanger in a pool permanently supplied with hot water from a low-energy geothermal borehole with a high flow rate. The choice of PVC material is attributed to the fact that hot geothermal waters are generally of an aggressive composition to steels and metals in general. The geothermal air heater allows the heating of the ambient cold air which is introduced into the exchanger and then extracted hot using an extraction fan. The hot air is then diffused into premises for heating during the winter season. The improvement in the performance of this type of exchanger is highlighted, in particular by acting on the number of pipes of the exchanger and the air flow rate using geothermal energy (low energy) as a source of renewable and clean energy. The experimental results obtained showed that the energy gain is a function of the length of the exchanger and the air flow rate. This gain can be up to 20°C between the inlet and outlet of the miniature exchanger model, which means that the proposed solution could be technically feasible.