High‐Performance Charging Method for Cold Energy Storage Using Foam Freezing

Phase change cold energy storage can effectively stabilize the peak value of the power grid, but the cold energy charging rate of phase change material decreases seriously which will reduce the energy efficiency of the system. The cold energy charging performance can be effectively improved by foam freezing, and the foam freezing model is proposed to explore the influence factors and the advantages of this method. Foam freezing is compared with other methods based on the novel concept of cold energy charging coefficient which is carried on the analogy to heat transfer coefficient. It is found that the cold energy charging rate of foam freezing are exponential functions of the height based on e . The foam cold energy charging coefficient is affected by the superposition of convective heat transfer intensity and bubble terminal velocity. The technical path of increasing the cold energy charging coefficient by continuously reducing the bubble size is not feasible. When foam freezing at the radius of 0.6 mm, the cold energy charging coefficient is 237.1 W m −2 K −1 , the water equivalent height is 18 mm, and it is the most economical. Foam freezing has advantages over the ice ball and ice‐on‐coil in cold energy charging performance.