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The chemical characteristics of the typha-starch composite have been investigated in this study to optimize the component of the habitat insulation panel obtained from the two bio sourced materials. Four mixtures have been formulated and tested (starch 0g + typha 620 g; starch 62g + typha 558 g; starch 93g + typha 527 g; starch 124g + typha 496 g). The panels were made up of six different granulometries (0.125 mm; 0.250 mm; 0.425 mm; 1.25 mm 1.70 mm; 3.15 mm). A total of 72 panels were made and tested. The density of the panels varies from 515.6 kg.m-3 to 809.74 kg.m-3. Chemical characterisation reveals that typha particles contain a high content of organic matter and dry matter, as well as a significant proportion of water and volatile components. The typha which contains very little protein, little minerals and lipids, could contribute to the thermosetting during the manufacturing process of insulating panels. Formulations with low mass density such as L91 (1.70 mm + 124 g starch) and G62 (1.25 mm + 0 g starch) show good thermal properties according to literature.

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In developing countries, institutions that have to operate continuously during daylight hours consume relatively large amounts of electrical energy for lighting and air conditioning, leading to high bills. Untimely power cuts lead to a fluctuation in the voltage delivered by the conventional network, which induces the malfunctioning of electrical equipment and the discontinuity of judicial work. The use of photovoltaic solar energy makes it possible, on the one hand, to ensure continuity of service in the event of damage, and on the other hand to stem greenhouse gas emissions through the sustainable nature of this energy.  Solar installations also make it possible to maintain the permanent power supply in the event of instability of the electrical network and to correct the voltage variations undergone by the energy equipment. Thus, this  (case) study  is based on the energy balances evaluated on the buildings of the jurisdiction of the city of Kandi (Benin) to propose effective solutions of electrification according to six (6) technical scenarii. Each component of the back up system has been sized considering technical requirements and an economic and environmental study has been carried out. The results indicate that the integrated scenario 6 of a "back-up" system with a solar fraction of up to 37% (49.5 kWc) seems to be the most suitable conf iguration for the current needs of the Kandi jurisdiction due to the shortest time to return on investment (5.1 years) and the maximum annual savings generated (33,674 USD). The environmental impact study has made it possible to determine the CO2  emissions avoided as well as the contribution of Carbon credits that this jurisdiction would reap has been evaluated at 115.8 tCO2  equivalent, or 10.6 hectares of forest carbon preserved over the life of the project. This configuration is therefore strongly recommended for a sustainable energy mix in the jurisdictions of Benin as well as for administrative or similar sites where electricity consumption is maximum during the day.

The results show that the variation in the swelling rate of some samples analysed describes a sinusoid with values higher than those recommended by the AINSI A 208.1 1999 standard. The use of these panels in a dry environment is therefore strongly recommended. The Young's modulus of elasticity (YME) and the breaking Modulus of Rupture (MOR) of the composite materials are between 0.91 and 2.31 GPa and 5.39 and 16.43 MPa. These values meet the 1999 ANSI 208.1 standard, which requires that the YEM and MOR of insulation boards in buildings be greater than or equal to 550 MPa and 3 MPa, respectively. Deformation at break varies between 8.40 and 13.05 mm. These values explain the non-ductile behaviour of these materials. Finally, the evolution of the mechanical properties of the material (Flexural Modulus of Elasticity (FME), MOR and deformation) as a function of the binder rate and the particle size distribution indicate that the presence of starch in the small particle sizes (≤ 0.425mm) favours the increase in the rigidity of the material. The breaking strength of the material (small granulometry) is greater with starch proportions ranging from 10 to 15%. The presence of the binder in the composite, whatever the granulometry, changes the behaviour of the material by increasing its deformation at breakage. With regard to flexural behaviour, typha particles with a particle size between 0.425 mm and 1.25 mm with a binder content of 10% to 15% are therefore more ductile. With these characteristics, the formulations M1 (10% starch; 0.425 mm) and M4 (15% starch; 0.425 mm) indicate the best mechanical properties.