IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask A Report, November 2009
Fig. 15: Schematic lay-out of an internal melt ice storage system
Hybrid systems
If an ice store can be discharged by external and internal melt simultaneously it is called a
hybrid system. The advantages of both systems are combined. The internal discharging
circuit melts the ice from the outer surface of the heat exchanger. Channels of liquid water
are generated between the heat exchanger surface and the ice mass. Simultaneously the
external discharging circuit circulates the liquid water.
Therefore hybrid systems allow a high discharging rate at a constant temperature level. Fig.
16 shows a schematic lay-out of a hybrid system.
Fig. 15: Schematic lay-out of a hybrid ice store system
5.2.1.2 Encapsulated Ice
An encapsulated Ice Storage System (EISS) consists of a steel containment filled up to 50-
70% with special plastic containers [Siemens Schweiz AG]. The containers have various
shapes and usually consist of polyethylene. The containers are filled with water or brine.
They are not completely filled to account for the volume expansion during the freezing
process. The containers are in direct contact with the heat transfer medium flowing through
the tank. For non pressurized systems a barrier has to be installed to keep the plastic
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