To offer the essential basic information for analyzing the thermal-energy storage system based on the form-stable phase change of plastics, particle-to-fluid heat transfer coefficients in fixed beds packed with cross-linked cylindrical plastic particles subjected to melt-freeze cycles were evaluated experimentally using the extended Schumann＇s theory, and a formula for estimating the heat transfer coefficient was presented. The resulting heat transfer coefficients were found to be definitely lower than those predicted from previously published work, due to the melt adhesion between adjacent plastic particles, which increases their contacting surface area and, consequently, increases the dead space in the interstitial flow region.