Experimental and numerical analyses are conducted to investigate the effect of the size of a form-stable phase change material (FS-PCM) on discharge characteristics of packed-bed latent heat storage columns. Two types of cross-linked polymer pellets having different dimensions are used as the FS-PCM and water is used as the heat transfer fluid (HTF). Experimental results on the heat transfer in the packed bed of each FS-PCM and the discharge characteristics of the packed bed are reported. By using the empirical equations for estimating the heat transfer coefficient between the FS-PCM and the HTF obtained in the present experiment, the transient variation of the temperature of the HTF at the outlet of the packed bed is calculated with a numerical method, and they agree with the experimental results under various operating conditions. It is also shown that by increasing the contact time between the FS-PCM and the HTF in the packed bed, the demerits caused by the thermal resistance in the FS-PCM and between the FS-PCM and the HTF are overcome.