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To improve the energetic efficiency of an unvented Trombe wall and to maximize the heat transfer rate between this type of walls and the interior ambiance of the building, thermal innovation, consisting in adding vertical thermal fins to the internal Trombe wall surface, was studied. The thermal behavior of this new Trombe wall configuration was investigated in a Mediterranean region using a small scale test room, and compared to a classical Trombe wall. The results showed that thermal fins contribute to an internal room temperature rise and a decrease in the external Trombe wall temperature. This conducts to have a significant improvement of the thermal efficiency of this solar system compared to a similar context without thermal fins. As a result, the finned Trombe wall is more efficient than the classical one for high solar radiation up to 400 W/m 2 and the maximum difference in the thermal efficiency between the two cases can reach 7% at a solar radiation intensity of up to 800 W/m 2 . Then, using the TRNSYS simulation software a new numerical model of a modified finned Trombe wall was developed and validated by the experimental results. The numerical study of the thermal fin height effect, on a real scale building, showed that the optimum thermal fin height was equal to 0.2 m and a 2 m 2 finned unvented Trombe wall conducts to the same results, in term of annual heating loads, as a 4 m 2 classical unvented Trombe wall. [ABSTRACT FROM AUTHOR]

In order to take advantage of the local climate many passive solar design techniques were applied to reduce buildings energy demands. In term of reducing heating demands, the Trombe wall system appears as one of these effective passive techniques providing that it was properly conceived. In this study a numerical model of a Trombe wall system was developed using TRNSYS software and validated by a small scale experimental prototype, located at the Laboratory of Thermal Processes of the Research and Technology Center of Energy (CRTEn) of Borj Cedria. This model was then adopted for the numerical investigation of Tunisian typical buildings. The results of the simulation show that approximately 77% of the total heating demand of a 16 m 2 non-insulated simple typical Tunisian building, can be realized by a vented Trombe wall of 8 m 2 . A 97% reduction of the annual heating loads was attained by a 6 m 2 Trombe wall area when the external walls of the considered simple building were double walls insulated by 5 cm of expanded polystyrene. [ABSTRACT FROM AUTHOR]