Patent Application
20190390921
The present invention relates to a cooling device using a latent heat storage material, a distribution packaging container, a distribution system, and a distribution method.
During transportation of foods, medical and pharmaceutical products, electronic parts, and the like, in order to prevent deterioration of their freshness or quality, distribution systems or services are employed that perform continuous temperature control to constant temperature from shippers to receivers, which provide current comfortable lives.
In such a constant-temperature logistics system, in general, a transported object is packaged within a thermally insulated box for suppressing heat transfer between the ambient temperature and the transported object; furthermore, in case of a large temperature difference from the ambient temperature and the resultant large heat transfer, a heat storage material (cold storage material) for absorbing or releasing the heat is added; and the resultant package is transported.
Currently, in constant-temperature logistics systems, transportation is often not directly performed from shippers to receivers, but is performed via transfer points because of, for example, arrangement of transport schedules, inspection of articles, or re-sorting of transported objects. Also in the transfer points, temperature control is required, and the articles are temporarily stored within equipment having electrical temperature-regulation and refrigerating functions such as freezing or refrigeration warehouses. In addition, when transportation, for example, from shippers to transfer points takes a long time, it is performed with vehicles having electrical temperature-regulation and refrigerating functions.
In the existing distribution systems, for the proper holding temperature ranges of transported objects, the heat-release or heat-absorption temperatures of heat storage materials and holding temperatures during transportation or at transfer points have been considered. However, no consideration has been given between heat storage materials and temperatures during transportation or at transfer points.
Thus, heat storage materials unnecessarily release heat or absorb heat during transportation or at transfer points, which is waste of energy. This necessitates an increase in the amount of cold storage materials and exchange of cold storage materials at transfer points. Thus, there has been a demand for a reduction in the costs.
Patent Literature 1 discloses a technique relating to a refrigerator storage including a refrigerator storage body for containing articles, and a cold storage device for internally cooling the storage, wherein the cold storage device is designed such that cold storage materials composed of a fluid having a cold storage function are freely insertable and removable, and cold storage material exchange apparatuses are disposed in all transfer points, to thereby achieve a reduction in the time taken for cold storage in the refrigerator storage.
Patent Literature 2 discloses a technique relating to a method for, without using any refrigerator cars, transporting refrigerated goods being held at a target refrigerating temperature that is a positive temperature during refrigerating transportation, the method including placing a cold storage material and refrigerated goods within a refrigerating box, preliminarily cooling (without freezing) a first cold storage member to a positive temperature, and placing a heat insulating material and the first cold storage member between a frozen second cold storage member and the refrigerated goods.
PTL 1: Japanese Unexamined Patent Application Publication No. 2001-66028
PTL 2: Japanese Unexamined Patent Application Publication No. 2005-300052
However, the technique described in PTL 1 requires exchange of cold storage materials at all points, and transportation needs to be routed through points having cold storage material exchange apparatuses, which strictly limits transportation routes. In addition, the cold storage materials are composed of fluid, which store sensible heat energy, hence a very small amount of energy. For this reason, the cold storage materials are indispensably exchanged in every point.
The technique described in PTL 2 employs the cold storage members having a melting temperature lower than refrigerated goods. Even when transportation is routed through a refrigeration warehouse, the temperature within the warehouse needs to be set higher than the melting temperature of the cold storage members, which accelerates melting of the cold storage members. In order to perform transportation for a long time, a large amount of cold storage members need to be mounted. This causes a decrease in the volume of transportable refrigerated goods for the volume of the packaging container.
Under such circumstances, an embodiment of the present invention has been made. An object is to provide a cooling device in which a latent heat storage material is at least made dormant during physical distribution, to thereby cause the cooling function to last longer.
The above-described object is achieved by an embodiment of the present invention having the following features. Specifically, a cooling device according to an embodiment of the present invention is a cooling device used for a distribution packaging container and configured to perform temperature adjustment of a cooling target article, the cooling device including: a latent heat storage material having a supercooling characteristic, and having a temperature range of a dormant period between a solidification temperature of start of a phase change from a liquid phase to a solid phase and a melting start temperature of start of a phase change from a solid phase to a liquid phase; and a containing region containing the latent heat storage material, wherein the latent heat storage material is selected in accordance with a proper holding temperature range of the cooling target article such that a main melting temperature falls within the proper holding temperature range of the cooling target article, and the temperature range of the dormant period and the proper holding temperature range of the cooling target article at least have an overlapping range.
According to an embodiment of the present invention, during a time period in which temperature control is not performed, the latent heat of the latent heat storage material keeps the cooling target article cool at or about the main melting temperature. In a case where the lower limit of the proper holding temperature of the cooling target article is lower than the solidification temperature, during a time period in which temperature control is performed, the temperature can be controlled by cooling to a temperature lower than the solidification temperature and higher than the lower limit, so that the latent heat storage material is subjected to a phase change from the liquid phase to a solid phase and thus regenerated. Alternatively, in other cases, during a time period in which temperature control is performed, the temperature can be controlled to a temperature within an overlapping range between the temperature range of the dormant period and the proper holding temperature range of the cooling target article, so that the latent heat storage material is at least made dormant, to thereby cause the cooling function to last longer.
Hereinafter, the definitions of terms in the present application will be described. The terms are construed as having the following definitions unless otherwise specified.
(1) The solidification temperature is a temperature at which a latent heat storage material in a liquid state held at the temperature starts to form crystal nuclei. In the present invention, the temperature is measured with a thermocouple: at least 50 ml of a latent heat storage material is charged into a polyethylene bottle, placed in a cool storage (including a refrigerator, a freezer, and a programmable thermostat), and measured while the temperature of the cool storage is decreased. The supercooling phenomenon is known to depend on volume; the inventors performed experiments and have demonstrated that, with volumes of 50 ml or more, the phenomenon is less likely to be affected by volume.
(2) The melting start temperature is a temperature determined: differential scanning calorimetry (DSC) provides a DSC curve, and the endothermic peak is extrapolated from the temperature of its start to the baseline.
(3) The main melting temperature is, in a DSC curve obtained by differential scanning calorimetry (DSC), the temperature of the endothermic peak. When a latent heat storage material in a solid phase is set at a temperature equal to or higher than the main melting temperature, during the phase change of the latent heat storage material to a liquid phase, the latent heat storage material remains at or about the main melting temperature.
(4) The temperature range of the dormant period (dormant period temperature range) is a temperature range between the solidification temperature and the melting start temperature of the latent heat storage material.
(5) The temperature range of a regeneration period is a temperature range equal to or lower than the solidification temperature of the latent heat storage material.
(6) Making the latent heat storage material dormant is to set the latent heat storage material in the temperature range of the dormant period, so that, when the latent heat storage material is in a solid phase, the solid phase is maintained; alternatively, when the latent heat storage material is in a liquid phase, the liquid phase is maintained. Alternatively, when both of the solid phase and the liquid phase are present, in other words, the latent heat storage material in the solid phase is exposed to an environment at a temperature higher than the melting temperature for a short period and partially melted, and the latent heat storage material is set to the temperature range of the dormant period, it is substantially maintained in that state; however, depending on conditions, for example, when the latent heat storage material is set at a temperature of the dormant period close to the solidification temperature, particles in the solid phase may function as crystal nuclei, to cause a phase change of a liquid phase region to a solid phase. By contrast, in the case of a latent heat storage material not having a dormant period, such a state in which both of a solid phase and a liquid phase are present is the phase transition state; even when the latent heat storage material is placed in an environment at a temperature equal to the phase change temperature, melting of the solid phase accelerates from the interface between the solid phase and the liquid phase.
(7) The regeneration of the latent heat storage material is to set the latent heat storage material at a temperature equal to or lower than the solidification temperature, to thereby cause a phase change from the liquid phase to a solid phase. In addition, in the temperature range of the dormant period, a phase change of a liquid phase region to a solid phase is also referred to as regeneration.
The inventors of the present invention have found the following findings: in the case of using a cooling device including a latent heat storage material to perform temperature adjustment of a cooling target article, a latent heat storage material is used that has a supercooling characteristic and has a temperature range of a dormant period between a solidification temperature of start of a phase change from a liquid phase to a solid phase and a melting start temperature of start of a phase change from a solid phase to a liquid phase, and the temperature is controlled to fall within the temperature range of the dormant period, so that the latent heat storage material is at least made dormant. Thus, the present invention has been made.
As a result, the inventors of the present invention enable, by at least making the latent heat storage material dormant during physical distribution, the cooling function to last longer. Hereinafter, embodiments according to the present invention will be specifically described with reference to drawings.
A cooling device according to an embodiment of the present invention is a cooling device used for a distribution packaging container and configured to perform temperature adjustment of a cooling target article, the cooling device including: a latent heat storage material having a supercooling characteristic, and having a temperature range of a dormant period between a solidification temperature of start of a phase change from a liquid phase to a solid phase and a melting start temperature of start of a phase change from a solid phase to a liquid phase; and a containing region containing the latent heat storage material.
The cooling device main body 110 has the containing region 120 that is a hollow structure for containing the heat storage layer 130. The cooling device main body 110 may be formed of a resin material such as polyethylene, polypropylene, polyester, polyurethane, polycarbonate, polyvinyl chloride, or polyamide; a metal such as aluminum, stainless steel, copper, or silver; or an inorganic material such as glass, pottery, or ceramic. From the viewpoint of ease of formation of the hollow structure and durability, preferred is a resin material. To the cooling device main body 110, a thermosensitive sticker indicating temperature is preferably affixed, which enables determination of the temperature of the cooling device.
The heat storage layer 130 includes a latent heat storage material 150 having a supercooling characteristic, and having a temperature range of a dormant period between a solidification temperature of start of a phase change from a liquid phase to a solid phase and a melting start temperature of start of a phase change from a solid phase to a liquid phase. The latent heat storage material 150 is preferably formed of a material that contains at least water molecules, which tends to provide a supercooling characteristic, and tends to provide a dormant period.
Specific examples include semi-clathrate hydrates of a C1-6 alkyl quaternary salt such as tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium nitrate, tetrabutylammonium benzoate, tributylpentylammonium bromide, and tetrabutylphosphonium bromide; clathrate hydrates of organic compounds having a molecular weight of 200 or less such as tetrahydrofuran, dioxane, cyclopentane, cyclohexane, and acetone; aqueous solutions of inorganic salts such as sodium chloride, potassium chloride, and ammonium chloride; and inorganic salt hydrates such as sodium acetate trihydrate and sodium sulfate decahydrate. From the viewpoint of use for physical distribution, that is, safety and sanitation, the latent heat storage material 150 is preferably formed of a low toxic and non-flammable material such as a semi-clathrate hydrate of a C1-6 alkyl quaternary salt, an aqueous solution of an inorganic salt, or an inorganic salt hydrate. In particular, preferred are aqueous solutions of semi-clathrate hydrates including alkyl quaternary salts as guests because they tend to have a supercooling characteristic, and have low toxicity and non-flammability. The latent heat storage material may be an aqueous solution of a semi-clathrate hydrate including an alkyl quaternary salt as a guest, the aqueous solution further including an inorganic salt such as potassium chloride, potassium bromide, cesium bromide, or potassium nitrate. A latent heat storage material that is an aqueous solution of a semi-clathrate hydrate including an alkyl quaternary salt as a guest or that is such an aqueous solution further including an inorganic salt is preferred because a latent heat storage material is easily provided so as to have a main melting temperature in a temperature zone higher than 0° C., in particular, a chilled temperature zone (more than 0° C. and 10° C. or less) or a temperature zone suitable for preservation of vegetables and fruits (more than 0° C. and 15° C. or less; in particular, in the case of vegetables and fruits that discolor or are damaged due to refrigeration at about 0° C. for a long time, such as green vegetables, 2° C. or more and 15° C. or less), and adjustments are easily performed using species of the alkyl quaternary salt and the concentration of the aqueous solution. A latent heat storage material that has a melting start temperature of 5° C. or more and a main melting temperature of less than 10° C. is preferred because it can be made dormant in a temperature zone of ordinary refrigeration equipment (more than 0° C. and 5° C. or less), and can be used for refrigeration and transportation for chilled goods and vegetables and fruits.
To the material for forming the heat storage layer 130, a supercooling inhibitor may be added in order to adjust the temperature range of the dormant period. The supercooling inhibitor is preferably a substance whose solubility sharply drops at a specific temperature equal to or more than the solidification temperature of the latent heat storage material 150 included in the heat storage layer 130, to precipitate as crystals, to thereby promote generation of nuclei of the latent heat storage material 150. In addition, from the viewpoint of safety and sanitation, the substance preferably has low toxicity. From such viewpoints, examples include salts soluble at room temperature in the latent heat storage material, such as potassium alum, ammonium alum, sodium carbonate, and disodium hydrogenphosphate. Alternatively, the supercooling inhibitor may be a powder that promotes generation of nuclei of the latent heat storage material, and is slightly soluble or insoluble in the latent heat storage material. From such viewpoints, examples include active carbon, aluminum oxide, titanium oxide, silver iodide, and sodium tetraborate. To the material for forming the heat storage layer 130, an antiseptic or an antimicrobial agent is preferably added. To the material for forming the heat storage layer 130, a thickener such as xanthan gum, guar gum, carboxymethylcellulose, or sodium polyacrylate may be added. Incidentally, materials in an embodiment of the present invention are not limited to the materials described above as examples.
The latent heat storage material 150 is selected in accordance with the proper holding temperature range specified for every cooling target article. In this case, the latent heat storage material 150 is selected such that the main melting temperature of the latent heat storage material 150 falls within the proper holding temperature range of the cooling target article, and the temperature range of the dormant period of the latent heat storage material 150 and the proper holding temperature range of the cooling target article at least have an overlapping range. As a result of such a selection, during a time period in which temperature control is not performed, the latent heat of the latent heat storage material 150 keeps the cooling target article refrigerated at or about the main melting temperature. During a time period in which temperature control is performed, the temperature can be controlled to be within the overlapping range between the temperature range of the dormant period and the proper holding temperature range of the cooling target article, so that the latent heat storage material 150 is at least made dormant, to thereby cause the cooling function to last longer.
When the latent heat storage material 150 is selected in accordance with the proper holding temperature range specified for every cooling target article, the latent heat storage material 150 is more preferably selected such that the main melting temperature of the latent heat storage material 150 falls within the proper holding temperature range of the cooling target article, and the solidification temperature of the latent heat storage material 150 is higher than the lower limit of the proper holding temperature range of the cooling target article. As a result of such selection, during a time period in which temperature control is performed, the temperature can be controlled to be a temperature within an overlapping range between the temperature range of the regeneration period and the proper holding temperature range of the cooling target article, so that the latent heat storage material 150 is subjected to a phase change from a liquid phase to a solid phase and thus regenerated. In this case, the temperature range of the dormant period is included in the proper holding temperature range of the cooling target article; thus, during a time period in which temperature control is performed, the temperature can be controlled to be within the temperature range of the dormant period, to make the latent heat storage material 150 dormant. In both of the case of regenerating the latent heat storage material 150 and the case of making the latent heat storage material 150 dormant, the cooling function is made to last longer.
In the latent heat storage material 150 used for the cooling device 100, the temperature range of the dormant period preferably spans 1° C. or more. As a result of using such a latent heat storage material 150, during a time period in which temperature control is performed, the temperature to which the latent heat storage material 150 is controlled in order to make it dormant can be flexibly set within the temperature range of the dormant period.
The distribution-packaging-container main body 210 includes a container part 240 and a lid part 250. The container part 240 has an opening for inserting and removing the article and the cooling device 100. The lid part 250 is used to seal the opening. The container part 240 and the lid part 250 may be connected together or separated from each other. In order to reduce heat transfer into or from the distribution packaging container 200, the lid part 250 is preferably configured to seal the container part 240.
The distribution-packaging-container main body 210 is preferably formed of a heat insulating material such as polystyrene foam, urethane foam, or a vacuum insulation material. Alternatively, on the inside or outside of a main body formed of a material without consideration of heat insulation, a heat insulating layer formed of a heat insulating material may be disposed. The distribution-packaging-container main body 210 may have such a size that a person can carry; alternatively, for example, a huge case such as a container may have the function of the distribution-packaging-container main body 210. The distribution packaging container may be a container equipped with a cooling apparatus, such as a reefer container. Such reefer containers can contain large amounts of articles, and can function as cool storages in a time period with power supply during transportation. Thus, the reefer containers are preferably used for import and export, which take a long time for transportation of articles. Existing reefer containers have difficulty in holding of the temperature of articles in a time period with no power supply, for example, during customs inspection; thus, deterioration of the freshness or quality of articles has been problematic. However, consider a case where a reefer container is used as a distribution packaging container according to an embodiment of the present invention, and a shipper places a cooling device according to an embodiment of the present invention and articles into the reefer container; as a result, in a time period with power supply, the cooling device according to an embodiment of the present invention goes into the dormant period, whereas, in a time period with no power supply, the latent heat storage material of the cooling device becomes active to hold the temperature of the articles to be in the proper holding temperature range. Thus, articles that undergo serious deterioration of freshness or quality due to deviation from the proper holding temperature ranges, such as wine, chocolate, and fruits, can be imported or exported in a time-consuming manner, or can be transported via flexibly selected routes.
The cooling-device holder 220 is disposed within the distribution-packaging-container main body 210. The distribution packaging container 200 is used such that the cooling device 100 is placed on the cooling-device holder 220. As a result, the inside of the distribution-packaging-container main body 210 is held at a temperature depending on the cooling device 100. The cooling-device holder 220 may have a structure so as to fix the cooling device 100. The cooling device 100 may be included within the distribution-packaging-container main body 210; alternatively, the cooling device 100 itself may serve as the distribution packaging container 200.
The cooling device 100 used for the distribution packaging container 200 is selected in accordance with the proper holding temperature range of the article to be packaged. The cooling device 100 is selected such that the latent heat storage material 150 used for the cooling device 100 has a main melting temperature falling within the proper holding temperature range of the article, and the temperature range of the dormant period of the latent heat storage material 150 and the proper holding temperature range of the article at least have an overlapping range. As a result of such selection, in a time period in which temperature control is not performed during physical distribution, the latent heat of the latent heat storage material 150 keeps the article refrigerated at or about the main melting temperature. In another time period in which temperature control is performed, the temperature can be controlled to be within the overlapping range between the temperature range of the dormant period and the proper holding temperature range of the cooling target article, so that the latent heat storage material 150 is at least made dormant, to thereby cause the cooling function to last longer.
The cooling device 100 is preferably selected such that the main melting temperature of the latent heat storage material 150 used for the cooling device 100 falls within the proper holding temperature range of the article, and the solidification temperature of the latent heat storage material 150 is higher than the lower limit of the proper holding temperature range of the article. As a result of such selection, in a time period in which temperature control is performed during physical distribution, the temperature can be controlled to be within the overlapping range between the temperature range of the regeneration period and the proper holding temperature range of the cooling target article, so that the latent heat storage material 150 is subjected to a phase change from a liquid phase to a solid phase and thus regenerated. In this case, the temperature range of the dormant period is included in the proper holding temperature range of the article; as a result, in a time period in which temperature control is performed, the temperature may be controlled to be within the temperature range of the dormant period, to thereby make the latent heat storage material 150 dormant. In both of the case of regenerating the latent heat storage material 150 and the case of making the latent heat storage material 150 dormant, the cooling function is made to last longer.
When the cooling device 100 is selected so as to employ the latent heat storage material 150 having the above-described temperature range, the cooling device 100 is more preferably selected such that the control temperature (setting temperature) such as refrigeration temperature or freezing temperature ordinarily set for cooling apparatuses (such as refrigeration (freezing) cars, refrigeration (freezing) warehouses, refrigeration (freezing) lockers, and reefer containers) commonly used for physical distribution falls within the overlapping range between the temperature range of the dormant period and the proper holding temperature range of the article, or in the overlapping range between the temperature range of the regeneration period and the proper holding temperature range of the article. Such selection is not necessarily possible; however, this selection enables physical distribution using the distribution packaging container 200 in physical distribution using a cooling apparatus set at an ordinary temperature, and transportation routes can be flexibly set.
When the cooling device 100 is selected such that the solidification temperature of the latent heat storage material 150 used for the cooling device 100 is lower than the lower limit of the proper holding temperature range of the article, in order to prevent direct contact between the article and the cooling device 100 and to prevent the temperature of the article-containing region 230 from decreasing to less than the lower limit of the proper holding temperature range of the article, the cooling device 100 is placed with a heat insulating material disposed between the article and the cooling device 100. In this case, the latent heat storage material 150 cannot be set to the solidification temperature or less for refrigeration during physical distribution; however, as described in the definition of the dormancy of the latent heat storage material, the latent heat storage material 150 may be regenerated while it is made dormant.
The article-containing region 230 is provided within the distribution-packaging-container main body 210, and an article having a predetermined proper holding temperature range is placed therein. Thus, the article is held at a temperature in the proper holding temperature range.
The distribution system according to this embodiment is a distribution system in which an article having a predetermined proper holding temperature range is packaged together with the cooling device 100 in a distribution packaging container 200, and transported from a shipper through a transporter to a receiver, the distribution system including a cooling apparatus configured to control the external temperature of the distribution packaging container 200 to the proper holding temperature range of the article before and/or after a time period in which temperature control is not performed, wherein the cooling apparatus is configured to cool the distribution packaging container 200 to an overlapping range between the temperature range of the dormant period of the latent heat storage material 150 used for the cooling device 100 and the proper holding temperature range of the article.
In the distribution system according to this embodiment, the cooling apparatus is preferably configured to cool the distribution packaging container 200 to a temperature that is lower than the solidification temperature of the latent heat storage material, and that is higher than the lower limit of the proper holding temperature range of the article, to thereby cause the latent heat storage material 150 to undergo a phase change from a liquid phase to a solid phase.
Hereinafter, a method for producing the cooling device 100 according to this embodiment will be described.
Subsequently, as illustrated in
Finally, the cooling device 100 is left at stand in an environment at a temperature equal to or lower than the solidification temperature of the latent heat storage material 150, to solidify the latent heat storage material 150. As a result of such steps, the cooling device 100 according to this embodiment is produced. As described here, the latent heat storage material 150 may be solidified before the cooling device 100 is placed in the distribution packaging container 200; alternatively, when the distribution packaging container 200 can be placed in an environment at a temperature equal to or lower than the solidification temperature of the latent heat storage material 150 in the initial stage of physical distribution, in this stage, the latent heat storage material 150 of the cooling device 100 may be solidified. Note that the technical scope of the present invention is not limited to the above-described embodiments; the embodiments can be modified in various ways without departing from the spirit and scope of the present invention.
Example 1 is an example of the cooling device according to the first embodiment. First, as illustrated in
In Comparative Example 2, a cooling device was prepared: to the same blow-molded container as in Example 1, water was injected in the same amount of 800 g as in Example 1, and the container was tightly plugged. The water was solidified in a freezer at about −18° C. to provide Comparative Example 2. This latent heat storage material was evaluated in terms of solidification temperature, melting start temperature, and main melting temperature by the same method as in Example 1. As a result, the solidification temperature was −10° C., the melting start temperature was −1° C., and the main melting temperature was 0° C.
An experiment was performed in which the ambient temperature was changed in accordance with a simulation: in accordance with the time schedule and temperatures described in
As illustrated in
By contrast, the cooling device of Comparative Example 2 exhibited a sharp temperature rise after 17 hours elapsed from the start of measurement, and, after 20 hours elapsed, the temperature reached the ambient temperature, 25° C. This is probably because the latent heat storage material composed of water has a main melting temperature of about 0° C.; even in refrigeration warehouses or refrigerator cars, the ambient temperature is the main melting temperature or higher, so that melting gradually proceeds; the latent heat has been used up at the time when about 17 hours elapsed, which resulted in the temperature rise. Thus, the temperature has deviated from the proper holding temperature range in a short time, so that it is difficult to keep freshness and quality for a long time.
In other words, in the case of employing water as a latent heat storage material, as described in the experiment, even when the article and the latent heat storage material are kept refrigerated in refrigeration warehouses or the like during physical distribution, the melting start temperature is lower than the temperature of the refrigeration warehouses (such as 3° C. to 10° C.); thus, the latent heat storage material needs to be appropriately exchanged, and the exchange causes transportation delay, which is problematic. By contrast, the cooling device and the distribution system employing the cooling device in Example 1, such a problem has been addressed, and the latent heat storage material is set by the shipper only in the initial stage of packaging of the article. In addition, as in Example 1, in the case of employing the latent heat storage material having the temperature range of the dormant period, equipment of regenerating (freezing) the latent heat storage material can be set at a refrigeration temperature of as high as 0° C. or more, which leads to energy conservation of the whole distribution system.
In the case of employing, as a latent heat storage material, water, which has the temperature range of the dormant period of −10° C. to −1° C. (values in the above-described experiment, but can be adjusted by addition of a supercooling inhibitor, for example), the latent heat storage material can be made dormant or regenerated by, during transportation of an article in which its proper holding temperature range and the range of −10° C. to −1° C. have an overlapping range, using a freezing warehouse or the like set in the overlapping range during physical distribution, as in Example 1. However, as in Comparative Example 2, when water is used for transportation of an article not having an overlapping range between the temperature range of the dormant period and the proper holding temperature range of the article, a period is present from the shipper to the receiver in which the controlled/held temperature range is higher than the main melting temperature; thus, the period of dormancy or regeneration is not present, so that melting proceeds, and the cooling period cannot be extended. In other words, even when a latent heat storage material has the temperature range of the dormant period, it needs to be selected in accordance with the proper holding temperature range of an article such that the main melting temperature falls within the proper holding temperature range of the article, and the temperature range of the dormant period and the proper holding temperature range of the article at least have an overlapping range.
Example 2 is an example of the cooling device according to the first embodiment. In Example 2, two cooling devices having a heat storage layer having the same configuration as in Example 1 were produced by the same method as in Example 1.
As illustrated in
Example 3 is an example of the distribution system according to the first embodiment. Example 3 is a simulation of a distribution system in which an electronic commerce dealer as a shipper ships vegetables and fruits having an article's proper holding temperature range of more than 0° C. and 15° C., and the receiver receives the vegetables and fruits via a refrigeration locker at 3° C. to 10° C. as a cooling apparatus, and carries them to the receiver's home. The simulation is, for example, a transaction in which the receiver receives goods from a refrigeration locker disposed in a station on the commuting route. First, the electronic commerce dealer packaged the cooling device of Example 1 and vegetables and fruits into the distribution packaging container illustrated in
Example 4 is an example of the cooling device according to the first embodiment. In Example 4, two cooling devices were prepared that were produced by the same method as in Example 1 except for use of, as the latent heat storage material, an aqueous solution containing 37 wt % tetrabutylammonium bromide and 8 wt % potassium nitrate. This latent heat storage material was evaluated in terms of solidification temperature, melting start temperature, and main melting temperature by the same method as in Example 1, and the solidification temperature was −12° C., the melting start temperature was 6° C., and the main melting temperature was 7° C. The cooling devices prepared were frozen in a freezer at −18° C., and subsequently stored in a refrigerator at 3° C. to 5° C., to bring the temperature of the cooling devices to 3° C. to 5° C.
An experiment of transportation from a shipper to a receiver was performed in accordance with ambient temperature and a time schedule of refrigeration in a refrigeration warehouse at an ambient temperature of 5° C. for 12 hours and subsequent transportation in an atmosphere at 30° C. for 24 hours, with mixed loading of dairy products as chilled goods having a proper holding temperature of more than 0° C. and 10° C. or less and green vegetables as vegetable goods having a proper holding temperature range of more than 0° C. and 15° C. or less, preferably 2° C. or more and 15° C. or less, with cooling devices of Example 4 and Comparative Example 2 placed into the distribution packaging containers illustrated in
As illustrated in
By contrast, in Comparative Example 2, after the lapse of about 3 hours from the start of measurement, the temperature neared 0° C., which is the main melting temperature of the Comparative Example 2; the temperature was held at about 0° C. until about 26 hours elapsed from the start of measurement, and then sharply increased to more than 10° C. after the lapse of about 33 hours. This is because the latent heat storage material composed of water has a main melting temperature of about 0° C., hence melting proceeds even within the refrigeration warehouse in which the ambient temperature is more than the main melting temperature; thus, the latent heat storage material completely melts after the lapse of about 26 hours from the start of measurement, so that refrigeration for a long time is difficult to achieve. The green vegetables after the transportation and after the lapse of 36 hours contained a large amount of water, and underwent noticeable discoloration and damage. This is because the green vegetables were refrigerated at about 0° C. for a long time of about 26 hours, and inferentially affected by cold damage.
In summary, the cooling device of Example 4 enables transportation for a long time during which deviation from the proper holding temperature range does not occur and freshness and quality are retained.
Example 5 is an example of the distribution system according to the first embodiment. In Example 5, a fishery producer as the shipper placed fresh fish, which was a perishable article having an article's proper holding temperature range of more than −10° C. and 5° C. or less, into a distribution packaging container in which cooling devices were disposed as illustrated in
Finally, the receiver received at the restaurant the distribution packaging container having been left at stand in the environment at an average temperature of 25° C. for 5 hours, and unpacked it. At this time, the article that was the fresh fish retained the initial freshness with no noticeable deterioration of freshness. In the cooling devices, the latent heat storage material included both of a solid phase and a liquid phase and did not completely melt. Thus, the cooling devices of Example 5 are dormant in the transportation period in the refrigerator car at 2° C. to 3° C., which enables extension of the refrigeration period.
By contrast, in a case of employing ice as the latent heat storage material of Example 5, melting proceeds also in the transportation period in the refrigerator car at 2° C. to 3° C.; as a result, at the time of receiving by the receiver, the ice completely melts, and the temperature increases beyond the upper limit of the proper holding temperature range. In summary, in the distribution system according to an embodiment of the present invention, the transportation period in the refrigerator car is provided in a range overlapping the temperature range of the dormant period of the latent heat storage material, which enables transportation for a long time.
An embodiment of the present invention has the following features: (1) a cooling device according to an embodiment of the present invention is a cooling device used for a distribution packaging container and configured to perform temperature adjustment of a cooling target article, the cooling device including: a latent heat storage material having a supercooling characteristic, and having a temperature range of a dormant period between a solidification temperature of start of a phase change from a liquid phase to a solid phase and a melting start temperature of start of a phase change from a solid phase to a liquid phase; and a containing region containing the latent heat storage material, wherein the latent heat storage material is selected in accordance with a proper holding temperature range of the cooling target article such that a main melting temperature falls within the proper holding temperature range of the cooling target article, and the temperature range of the dormant period and the proper holding temperature range of the cooling target article at least have an overlapping range.
As a result, during a time period in which temperature control is not performed, the latent heat of the latent heat storage material is used to refrigerate the cooling target article at or about the main melting temperature. In a case where the cooling target article has a proper holding temperature having a lower limit lower than the solidification temperature, during a time period in which temperature control is performed, the temperature can be controlled by cooling to a temperature lower than the solidification temperature and higher than the lower limit, so that the latent heat storage material is subjected to a phase change from a liquid phase to a solid phase and thus regenerated. Alternatively, in other cases, during a time period in which temperature control is performed, the temperature can be controlled to a temperature within the overlapping range between the temperature range of the dormant period and the proper holding temperature range of the cooling target article, to thereby make the latent heat storage material at least dormant, to cause the cooling function to last longer.
(2) In the cooling device according to an embodiment of the present invention, the latent heat storage material is selected such that the solidification temperature is higher than a lower limit of the proper holding temperature range of the cooling target article.
As a result, during a time period in which temperature control is performed, the temperature can be controlled to a temperature lower than the solidification temperature of the latent heat storage material, and higher than the lower limit of the proper holding temperature range of the cooling target article, so that the latent heat storage material is subjected to a phase change from a liquid phase to a solid phase, and thus regenerated.
(3) In the cooling device according to an embodiment of the present invention, in the latent heat storage material, the temperature range of the dormant period spans 1° C. or more.
In this case, the temperature range of the dormant period spans 1° C. or more, so that, during a time period in which temperature control is performed, the temperature to which the latent heat storage material is controlled in order to make it dormant can be flexibly set within the temperature range of the dormant period.
(4) In the cooling device according to an embodiment of the present invention, the latent heat storage material uses formation energy of a semi-clathrate hydrate having an alkyl quaternary salt as a guest.
As a result, a cooling device employing a latent heat storage material having a dormant period can be specifically produced.
(5) In the cooling device according to an embodiment of the present invention, the latent heat storage material is non-flammable.
As a result, even when such a cooling device employing the latent heat storage material is used in physical distribution, higher safety can be achieved.
(6) In the cooling device according to an embodiment of the present invention, in the latent heat storage material, the melting start temperature is 5° C. or more and less than 10° C., and the main melting temperature is more than 5° C. and 10° C. or less.
As a result, the cooling device can be made dormant in ordinary refrigeration equipment, and can be applied to physical distribution of vegetables and fruits and chilled goods.
(7) A distribution packaging container according to an embodiment of the present invention is a distribution packaging container for packaging an article, the distribution packaging container including: a distribution-packaging-container main body; the cooling device according to any one of (1) to (6) selected in accordance with a proper holding temperature range of the article to be packaged; a cooling-device holder disposed within the distribution-packaging-container main body and holding the cooling device; and an article-containing region disposed within the distribution-packaging-container main body and configured to contain the article.
As a result, the cooling device employing a latent heat storage material having a dormant period can be used for physical distribution.
(8) A distribution system according to an embodiment of the present invention is a distribution system in which an article having a predetermined proper holding temperature range is packaged in the distribution packaging container according to (7), and transported from a shipper through a transporter to a receiver, the distribution system including: a cooling apparatus configured to control an external temperature of the distribution packaging container to the proper holding temperature range of the article before and/or after a time period in which temperature control is not performed, wherein the cooling apparatus is configured to cool the distribution packaging container to an overlapping range between the temperature range of the dormant period and the proper holding temperature range of the article.
As a result, in the distribution system employing the distribution packaging container employing the latent heat storage material having a dormant period, the latent heat storage material is at least made dormant, to thereby cause the cooling function to last longer.
(9) A distribution system according to an embodiment of the present invention is a distribution system in which an article having a predetermined proper holding temperature range is packaged in the distribution packaging container according to (7), and transported from a shipper through a transporter to a receiver, the distribution system including: a cooling apparatus configured to control an external temperature of the distribution packaging container to the proper holding temperature range of the article before and/or after a time period in which temperature control is not performed, wherein the cooling apparatus is configured to cool the distribution packaging container to a temperature that is lower than the solidification temperature of the latent heat storage material and higher than a lower limit of the proper holding temperature range of the article, to cause the latent heat storage material to undergo a phase change from a liquid phase to a solid phase.
As a result, in the distribution system employing the distribution packaging container employing the latent heat storage material having a dormant period, the latent heat storage material can be regenerated, to thereby cause the cooling function to last longer.
(10) A distribution method according to an embodiment of the present invention is a distribution method in which an article having a predetermined proper holding temperature range is packaged in the distribution packaging container according to (7), and is transported from a shipper through a transporter to a receiver, the distribution method including: a step of using a cooling apparatus to control an external temperature of the distribution packaging container to the proper holding temperature range of the article before and/or after a time period in which temperature control is not performed, wherein the cooling apparatus cools the distribution packaging container to an overlapping range between the temperature range of the dormant period and the proper holding temperature range of the article.
As a result, in the distribution method employing the distribution packaging container employing the latent heat storage material having a dormant period, the latent heat storage material can be at least made dormant, to thereby cause the cooling function to last longer.
(11) A distribution method according to an embodiment of the present invention is a distribution method in which an article having a predetermined proper holding temperature range is packaged in the distribution packaging container according to (7), and is transported from a shipper through a transporter to a receiver, the distribution method including: a step of using a cooling apparatus to control an external temperature of the distribution packaging container to the proper holding temperature range of the article before and/or after a time period in which temperature control is not performed, wherein the cooling apparatus cools the distribution packaging container to a temperature that is lower than the solidification temperature of the latent heat storage material and higher than a lower limit of the proper holding temperature range of the article, to cause the latent heat storage material to undergo a phase change from a liquid phase to a solid phase.
As a result, in the distribution method employing the distribution packaging container employing the latent heat storage material having a dormant period, the latent heat storage material can be regenerated, to thereby cause the cooling function to last longer.
The present international application claims priority to Japanese Patent Application No. 2017-019962, filed Feb. 6, 2017, and the entire contents of Japanese Patent Application No. 2017-019962 are herein incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-019962 | Feb 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/003948 | 2/6/2018 | WO | 00 |
