Abstract: A phase change thermal storage unit having has at least one conformational feature selected from (i) a fill port located proximate a corner of the of the panel, (ii) internal contouring that alters the thickness of the phase change material retention chamber for creating an average thickness of the chamber within a central portion of the chamber which is less than the average thickness of the chamber within a peripheral portion of the chamber, and (iii) fingertip indentation handles proximate each and every edge.