The invention relates to a cold storage element retaining low temperatures in refrigeration system during power outages or power off. More particularly, the present invention relates to cold storage element for maintaining low temperatures in domestic refrigerators during power
failures.
Background of the Invention:
Refrigeration systems find widespread use in homes, offices and industries. Domestic refrigerators are used to store food, beverages and other products including medicines and cosmetics.
A refrigeration system provides a low temperature storage region that is known to help keep food edible for a longer period. Refrigeration involves the slowing down of bacterial activity present in most food products. Moreover, a refrigerator provides a closed storage zone that inhibits contamination of food.
For example, milk when left at room temperature for a period of 3 to 4 hours tends to curdle and spoil. However, milk when stored at low temperatures, of approximately 5 to 8 degrees, can be stored for a substantially larger period of time, sometimes as much as a week. Essentially, lower temperatures aid in food preservation and the domestic refrigerator is relied upon for that purpose.
Most refrigeration systems, especially domestic refrigerators, are not provided with power back up systems, and thus do not work in situations of power failure, refrigerator malfunctioning or even a power off for cleaning or other purposes.
In these situations, when the refrigerator is not functioning on account of any number of reasons some of which have been mentioned above, the temperature inside the refrigerator gradually starts increasing.
The power situation in developing countries such as India, Bangladesh, Sri-Lanka etc is unreliable at best. Cities and towns in countries such as India often face frequent power outages. This results in food and other products stored in the refrigerator undergoing a substantial variation in temperatures, during periods of power off and subsequent power on. The rise in temperature within the refrigerator also results in corresponding rise in the contents of the refrigerator thereby causing the bacterial activity to resume in the edible content.
European Patent. No. 0098052 describes freezers comprising an outer housing and a door inside which the said freezer contains a number of shelves upon which food products are stored. Each shelf comprises a casing filled with brine solution having a eutectic temperature a few degrees lower than the operating temperature of the freezer. An evaporator coil, forming part of a refrigeration system of the freezer, is immersed in the brine solution in each casing.
The aforementioned arrangement makes it difficult to change the storage capacity of a freezer. Moreover the afore-cited arrangement comprising the evaporator coils and the brine solution are integral part of the refrigeration system and are not removable. But the abovementioned arrangement is primarily used in commercial refrigeration systems.
European Patent Application No. 0152155 relates to a plurality of cold storage elements for chest freezers used for commercial purposes. Each cold storage element comprises of a casing of plastics material containing sodium or ammonium salts (brine solution), which are constructed so as to be removably mounted in a chest freezer.
The above references are incorporated herein where appropriate teachings of additional or alternative details, features and/or technical background.
Moreover the temperature retention capacity of the eutectic solution or brine solution used in
the patents cited above is less than the cross-linked hydrated salt solution as used in the
present invention. Also, in case of brine solutions, it is very difficult to maintain the shape of
the element, as there are points at which bulging effect is observed when the solution inside
solidifies.
The abovementioned Patents are for chest Freezers, the instant invention relates to domestic
refrigerators.
SUMMARY OF THE INVENTION
In order to obviate the aforementioned drawbacks, the present invention relates to a cold storage element for maintaining or retaining low temperatures in refrigeration systems during power failure or power off situation.
The invention provides for an cold storage element which absorbs heat during power failure or power off situation of the refrigeration system and helps in retaining temperature for lengthy time period
The invention provides for an improved feature useful in storing edible products for a longer period of time during power failure in refrigerators
The invention also provides for keeping the food edible for a lengthy time period.
It is further object of the invention that allows for saving of electricity by avoiding continuous operation of the refrigerator compressor.
The invention can also be shifted to the refrigeration section to preserve vegetables and other food item for a longer period of time
To achieve the aforementioned objects, the present invention, provides a plurality of cold-storage elements for refrigeration systems, each element comprising a casing of plastic material, characterized in that said casing has at least one opening through which the phase change material (PCM), is poured and a cap to seal the said openings. The phase Change material (PCM) is an inorganic hydrated salt solution having high heat of fusion such as a mixture of water and a super absorbent material. The casing is preferably made from Low Density Polyethylene and the super absorbent material is cross -linked Sodium Polyacrylate.
The storage element is constructed to be removably mounted in the refrigeration area. In particular, the storage element is used in such a way that the abovementioned solution becomes solid during the operation of the compressor. The above-mentioned arrangement of the present invention is called Ice Pack, which helps in retaining/maintaining low temperature during power failure for lengthy time period.
Brief description of the accompanying drawings:
The features of this invention are set forth with particularly in the appended claims. The invention, together with its objects and advantages thereof may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify substantially like elements in the several figures and in which:
Figure 1 illustrates a conventional refrigeration system for preserving edible products.
Figure 2 represents the portable cold storage element used to retain temperature in case of power failure or power off in refrigeration systems.
Figure 3 illustrates the Cold storage element sealed with a cap containing the cross-linked hydrated salt solution.
Figure 4 illustrates one of the possible positions where cold storage element is placed within the refrigeration systems.
Detailed description of the invention:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
Through out the patent specification, a convention employed is that in the appended drawings, like numerals denote like components.
Figure 1 illustrates a conventional refrigeration system consisting of two sections, the Freezer section (1) and the refrigeration section (2) highlighting the preferred positioning of the portable cold storage element (3) in the freezer section. This feature is very useful in storing food for a lengthy period of time during power failure. Alternatively, during power cut the portable cold storage element can be removed from the Freezer section and inserted in the refrigerator section to maintain the vegetables and other edible items in the refrigerator section at a lower temperature.
With reference now to figure 2, abovementioned cold storage element (3) is designed as a shelf in Freezer section where the temperature is around -15° C and remains in a solid state. The cold storage element is made out of a plastic material for example Low density Polyethylene (LDPE) and contains Phase Change Material (PCM), which is a Super absorbent Liquid named Sodium Polyacrylate, a crossed linked component having more temperature retention capacity as compared to the solutions mentioned in previous patents. Alternatively aforementioned cold storage element can also placed in the refrigerator section.
With reference now to figure 3, cold storage element (3) is made by blow moulding process using LDPE material and contains a Phase Change Material (PCM). It has an opening (4) through which the hydrated salt solution i.e. PCM is poured into the element. The solution is blue in color and the said cold storage element is sealed with a cap (5) so that the liquid does not come in contact with atmosphere. The PCM is maintained in solid state during the normal operation of the refrigeration system. When the power failure occurs, the PCM changes its state from solid to liquid. In the abovementioned situation, the PCM gradually starts absorbing heat from the freezer section and thus, maintains low temperature for around 60-65 minutes in the absence of power supply or refrigerator malfunctioning. The refrigeration section can preserve vegetables and other edible products for a period of 100-110 minutes approximately.
With reference now to figure 4,cold storage element as mentioned above is designed as a shelf (6) in the freezer section. Alternatively it can also be used in the refrigeration section. For example it can be used as a stand or as a shelf between the cabinet liner.
The present invention is not to be limited in scope by the specific embodiments and examples, which are intended as illustrations of a number of aspects of the invention and any embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described
herein. These and all other equivalents are intended to be encompassed by the following claims.

We Claim:
1) A cold-storage element for refrigeration system for maintaining or retaining low
temperatures during power failure or power off, each element comprising:
a casing, characterized in that said casing has at least one opening through which the phase change material (PCM), is poured and a cap to seal the said opening.
2) The cold-storage element as claimed in claim 1 wherein said phase change material
(PCM), is an inorganic hydrated salt solution having high heat of fusion.
3) The cold-storage element as claimed in claim 2 wherein, said hydrated salt solution is
a mixture of water and a super absorbent material.
4) The cold-storage element as claimed in claim 3 wherein, the said super absorbent
material is cross -linked Sodium Polyacrylate.
5) The cold-storage element as claimed in claim 1 wherein the casing is made from Low
Density Polyethylene.
6) The cold-storage element as claimed in claim 1 wherein the element is placed within
the freezer section or the refrigeration section of the refrigeration system.

7) The cold-storage element for refrigeration system maintaining or retaining low
temperatures during power failure, each element substantially as herein described with reference to the accompanying drawings.