IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask A Report, November 2009
containers from buoying upwards once they are frozen. Fig. 16 shows a schematic diagram
of an encapsulated ice storage system.
Fig. 16: Schematic diagram of an encapsulated ice storage system
During the charging process the plastic containers are floating in the heat transfer medium
(e.g. water/glycol mixture) which has a temperature between −3 °C and −6 °C. The ice
grows from the inside of the plastic container walls to their centre.
During the discharging process the ice inside the plastic containers starts to melt, at first at
the container walls. Once the ice is completely detached from the container wall the heat
transfer rate decreases since there is no direct contact between ice and plastic container
wall anymore (Fig. 17). Because of this effect the discharging rate decreases and the
discharging temperature increases.
Fig. 17: Solidification and melting processes in a plastic container during charging and
discharging of an encapsulated ice system
5.2.1.3 Sheet Ice Harvester System
A sheet ice harvester system (SIHS), shown in Fig. 18, generates the ice outside of the
storage tank. Water extracted from the bottom of the storage tank is sprayed over
evaporator plates. An additional recirculation circuit is needed. A thin ice layer is formed at
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