Refrigeration – Intermediate fluid container transferring heat to heat... – Flow line connected transfer fluid supply and heat exchanger
Patent
1995-02-06
1996-11-12
Sollecito, John M.
Refrigeration
Intermediate fluid container transferring heat to heat...
Flow line connected transfer fluid supply and heat exchanger
62393, 165110, F25D 1202
Patent
active
055728839
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to cold storage apparatus and in particular to ice storage apparatus.
Ice storage provides the means to shift electrical load for cooling for instance air conditioning systems. As shown in FIG. 1, during off peak periods the chiller plant runs to charge up the ice store and then during peak periods (day time periods) the store can be used to provide some or all of the buildings' cooling requirements.
Much work has been done in developing an efficient means of providing cold storage in the form of ice store. An efficient cold storage method for producing ice uses a direct contact evaporator. Such an arrangement is disclosed in U.S. Pat. No. 4,864,831. In this arrangement a refrigerant is brought into direct contact with water in a tank to form ice which is used for heat exchange to provide chilled water for use in air conditioning. The refrigerant is sprayed onto or into the water and evaporates to absorb its latent heat of evaporation from the water, thus forming ice. The evaporating gaseous refrigerant is then condensed and recirculated. Although this method has an advantage of direct contact between the refrigerant (heat transfer fluid) and the water (storage liquid), it is important to ensure that no water vapour is carried over with the refrigerant vapour to the compressor if conventional compressors are to be used. Otherwise, non-conventional compressors must be used.
Thus the object of the present invention is to provide a direct contact cold storage apparatus which avoids the problem of water vapour being carried over with the refrigerant vapour and provides for efficient heat transfer.
The present invention provides cold storage apparatus comprising a vessel containing a storage liquid and a heat transfer liquid in direct contact with said storage liquid to transfer heat thereto or therefrom, said liquids being immiscible and of different densities, said heat transfer liquid remaining liquid during heat transfer, said storage liquid comprising a liquid which solidifies when sufficiently cooled by said heat transfer livid, the solidified storage liquid having a different density to said storage liquid, said liquids forming by gravity sequentially within said vessel a first layer of said heat transfer liquid, a second layer of said storage liquid, and a third layer of said solidified storage liquid; said cold storage apparatus including heat transfer liquid circulating means to deliver said heat transfer liquid to and from said vessel, said heat transfer liquid circulating means being arranged to deliver said heat transfer liquid into said first layer or said second layer at a temperature below the freezing point of said storage liquid.
Preferably the heat transfer liquid circulating means is arranged to deliver the heat transfer liquid into said second layer.
Preferably said solidified storage liquid is less dense that said storage liquid, and said heat transfer liquid is denser than said storage liquid. Conveniently in such an arrangement said storage liquid comprises water.
In one embodiment said heat transfer liquid circulating means is arranged to inject said heat transfer liquid in the form of droplets into said second layer.
In one embodiment feed means are provided to inject the storage liquid from the second layer into the heat transfer liquid in the heat transfer liquid circulating means at a position before the heat transfer liquid enters said second layer.
In one embodiment said feed means includes a pump to pump said storage liquid into said heat transfer liquid.
In another embodiment said heat transfer liquid circulating means includes a circulating conduit, and said feed means comprises a venturi arranged in said conduit, said venturi having an opening in a wall of a constricted part thereof, through which in use said storage liquid passes into said heat transfer liquid.
Preferably the heat transfer liquid circulating means includes a pump and heat exchange means.
In one embodiment a refrigeration circuit is coupled to the heat exchanging means to cool the
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EA Technology Limited
Sollecito John M.
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