Thermal performance analysis of a 20-feet latent cold energy storage device integrated with a novel fin-plate unit for building cooling

A 20-feet latent cold energy storage device integrated with a novel fin-plate unit was used to cool a 400 m² building space, in which the cold energy could be generated from renewable energy, industrial waste cold, or off-peak electricity. Due to the low thermal conductivity of n-pentadecane, a novel fin-plate unit was designed to improve the heat transfer rate of PCMs especially for the restricted charging process. Meanwhile, energy storage efficiency of the device under different operating parameters was analyzed. The results showed that the introduction of straight fin significantly accelerated the solidification process of encapsulated PCMs. Compared with straight fin, the branch fin (l_Branch = 30 mm, α = 120°) that had the same volume was found to shorten 27.7% of the charging time. While such branch fin could only shorten 2.8% of the discharging time, which might be attributed to the balance between the contribution and the restrictiveness for heat transfer caused by the fin. The small inlet velocity of 0.03 m/s was shown to contribute to a high energy storage efficiency of 86.83% and a long output time of 12.08 h. The results of this work were expected to provide the foundation for building the low-carbon architecture.