“Experimental Study on the Effect of Insertion of Copper Lessing Rings in Phase Change Material (PCM) on the Performance of Thermal Energy Storage Unit”, alkej, vol. 11, no. 4, pp. 60–72, Dec. 2015, Accessed: May 02, 2024. [Online]. Available: https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/265