Experimental investigation of ice melting system with open and closed ice-storage tanks combined internal and external ice melting processes.

• A new ice-storage experimental system with closed and open ice-storage tanks is developed. • The cold release rate of the CIST is more stable than that of the OIST under the same conditions. • The cumulative discharging capacity of CIST with 0 ∘C–3 ∘Cis a certain larger than that of OIST. • The problem of "millennium ice" is solved by combination of the external and internal ice melting. A new ice-storage experimental system with a closed (CIST) and an open (OIST) ice-storage tank has been exploited, with which the external ice melting processes are studied experimentally. Furthermore, the researches on combinations of external and internal ice melting have been carried out. The experiments indicate that the cold release rate of CIST is more stable than that of OIST under the same conditions, especially, the cold release rate of OIST decreases significantly at the later stage of the discharging process. The outlet temperature of the discharge water flowing from the bottom-to-top (Mode 1) is lower than that from the top-to-bottom of the ice-storage tank (Mode 2). With the relatively lower volumetric-flow rate, the outlet temperatures of the discharge water rise slowly, meanwhile, the cold release rate is also relatively lower. To solve the problem of "millennial ice" in the external system without an air-agitation device, two types of the combination of external and internal ice melting have been adopted, one is to adopt internal ice melting at first, and then external ice melting, the other is to adopt simultaneously the internal and external ice melting. The experiments show that the cumulative discharging capacity of the latter has been significantly improved. [ABSTRACT FROM AUTHOR]