Flat plate solar air collectors can further increase their overall thermal conductivity and heat storage capacity by using phase change materials (PCM) and refining their structural design, which will increase their stability and effectiveness of heat collection. Based on sodium sulfate decahydrate (SSD, Na2SO4·10H2O) and sodium acetate trihydrate (SAT, CH3COONa·3H2O), this research proposes a novel manufacturing procedure to manufacture a new binary mixed hydrated salt (SSD/SAT), which addresses phase separation and undercooling difficulties.The latent heat of phase transition hits 229 J/g−1 when the material's phase transition temperature is 61.71 °C. Furthermore, the numerical modeling of the SSD/SAT material's heat collection performance was conducted when it was integrated into a V-corrugated flat plate solar collector (VC-FPSC). The collector has been found to be able to extend the heat and boost the efficiency. •A preparation method has been proposed that can reduce the phase separation of binary mixed hydrated salts.•The manufactured SSD/SAT can efficiently lessen sodium sulfate decahydrate's phase separation and significant subcooling.•The V-corrugated flat plate collector with SSD/SAT can increase the effectiveness of heat collecting and lengthen the heating time.