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This paper presents a study on energy performance of an earth air heat exchanger (EAHE) for buildings in Maghreb climatic context (Oran, Bechar and Adrar cities in Algeria). In order to check the influence of the material, two air conducts (one of galvanized sheet metal and the other in polyvinyl chloride–PVC) are considered under the same geometric conditions (a 20 m conduct length, 120 mm diameter and 2 m burial depth). They are used separately for the ventilation in simple current flow of two adjoining rooms constituting a test cell located at the university campus IGCMO-USTOMB (Oran, Algeria). An experimental device has been set up to measure the temperature at different points (air inlet/outlet air duct). Measurements were run in August 2015, and the monitoring of both exchangers allowed us to evaluate their cooling performance: 35.41% for the Zinc pipe and 58.42% for the PVC pipe. Experimental results were compared to those obtained from the simulation (under the Trnsys 16) and a fair similarity is obtained. In order to optimize the energy performance of the exchanger (EAHE), numerical simulations are carried out by varying different parameters: climate, burial depth, length and diameter of the duct. Other simulations have shown that the energy supplied by the cooling exchanger (EAHE) is more significant in the south of the country (Adrar and Bechar) than in the north (Oran). [ABSTRACT FROM AUTHOR]

• Combined solar heating system (SSTC): DSF and storage tank. • Energy performance of a SSTC for heating needs in the Maghreb climatic context. • A storage tank with integrated double exchangers as a back-up heater in the evening. • A numerical model of the SSTC system was developed under the TRNSYS environment. • A two-stage regulation strategy of the storage tank function, between day and night, where the efficiency of the storage tank as an energy booster has been adapted. This paper presents the study of the energy performance of a solar thermal combined system (STCS) composed of: a solar thermal collector; a storage tank with double heat exchangers and a floor heating system to meet the heating needs of a local taken in the Maghreb climate context. The original idea of this study is the consideration of a storage tank with integrated double exchangers allowing on the one hand the accumulation of heat under the action of the exchanger1 connected to the circuit of the collector, to receive the surplus of solar thermal energy during the day and on the other hand to supply it under the action of the exchanger2 as auxiliary heating in the evening to the heating floor. A numerical model of the STCS system was developed under the TRNSYS simulation program. For the validation of the model of the heating floor coupled with the solar thermal collector (DSF), the results obtained by simulation were compared to those from the experiment conducted on a test cell equipped with a heating floor in the climatic conditions of the city of Oran. Other simulations of the STCS system were performed by integrating the storage tank and considering a function regulation strategy, in two stages of the storage tank, between day and night where the efficiency of the tank as a back-up heater was evaluated. The results obtained by simulation show the reliability of the model and the efficiency of the storage tank used as a back-up heater with a coverage rate of 91%. The combined solar thermal system STCS provides energy savings by substituting electric or gas back-up with active solar storage, under the application of an energy management strategy. [ABSTRACT FROM AUTHOR]