Heat transfer and flow analysis of a double-pass solar air heater with sandwich-structured PCM cylinders. - Ud Din, Sahibzada Imad; Ibrahim, Adnan; Fazlizan, Ahmad; Ludin, Norasikin Ahmad; Afham Rahmat, Muhammad Aqil; Shahid, Muhammad Ashhad; Al-Aasam, Anwer.B.; Mohd Rosli, Mohd Afzanizam; Aziat Bin Ishak, Muhammad Amir (Solar Energy, 2026)