Abstract: Aiming at the problem of space-time mismatch of solar heat utilization,a kind of heat accumulator of phase change with radial fins is designed and fabricated. The characteristics of the heat discharge power of the heat accumulator and the solid fraction of the phase change material during the heat discharge process are studied experimentally and numerically. The effects of cooling water flow rate,water influent mode and fin type on the heat discharge performance are discussed. The results show that the heat discharge process of the heat accumulator can be divided into three stages:liquid sensible heat stage,latent heat stage and solid sensible heat stage. The latent heat release of phase change materials during the latent heat stage makes the heat discharge power decrease relatively slowly. The case with the higher flow rate of water behaves,the faster decrease rate of heat discharge power and the shorter solidification time. The effect of water influent mode on the heat transfer feature is not obvious,but it can improve the heat transfer uniformity of heat accumulator. Compared with the flat fin,the heat conduction of phase change material between each fin element for the radial fin is more uniform,the solidification time for that is reduced by 31%,and the heat transfer rate for that is improved.