JP7560053B2 - Refrigerants, refrigeration equipment, cargo, transport equipment, transport method and refrigeration method - Google Patents

Description

This disclosure relates to ice packs, ice packs, cargo, transport equipment, transport methods, and ice pack methods.

There is known a cooling agent (sometimes called a cooling storage agent or ice pack, etc.) that is used to transport food and the like in a cooled state (for example, Patent Document 1). Note that, conventionally, the term cooling agent may refer not only to the cooling agent but also to the entire container in which the cooling agent is enclosed, but in this disclosure, the cooling agent refers to the cooling agent itself, and the entire combination of the cooling agent and the container in which the cooling agent is enclosed is referred to as a cooling device.

In commonly available cooling devices, the ice pack is made by adding various additives to water. Examples of additives include preservatives, freezing point depressants, thickeners, antifreeze, and colorants. In cooling devices, the ice pack is frozen in a freezer, for example, and then packed together with the object to be kept cold (e.g., food). The temperature of the freezer is generally set to -20°C to -10°C, and therefore the ice pack is set to a temperature of -20°C to -10°C when it is first used.

Patent Document 1 discloses an ice pack containing water, lithium chloride, and sodium chloride. This ice pack has a melting temperature (sometimes called the melting point) of -74°C, and is characterized by using latent heat to keep things cool near this temperature.

JP 2017-128622 A

In recent years, the demand for cryogenic cooling has increased due to the need to transport vaccines at extremely low temperatures (for example, below -70°C). Therefore, it is desirable to increase the variety of ice packs that can be used for cryogenic cooling.

The ice pack according to one embodiment of the present disclosure contains methanol.

In one example, the ice pack further contains water, and the mass of the methanol in relation to the mass of the water and the methanol is 40% or more.

In one example, the mass of the methanol in the total mass of the water and the methanol is 60% or less.

In one example, the mass of the water and the methanol in the ice pack is 90% or more.

In one example, the ice pack further comprises xanthan gum.
The ice pack according to any one of claims 1 to 4.

In one example, the ice pack further includes a water-absorbing polymer.

The cooling device according to one aspect of the present disclosure includes the above-mentioned cooling agent and an enclosure in which the cooling agent is enclosed.

The cargo according to one aspect of the present disclosure includes the above-mentioned cooling device, an object to be kept cold, and a storage container that contains both the cooling device and the object to be kept cold.

A transport device according to one aspect of the present disclosure includes the above-mentioned cooling device, an object to be kept cold, and a storage container that contains both the cooling device and the object to be kept cold.

A transportation method according to one aspect of the present disclosure includes the steps of storing the cooling device and the object to be kept cold together in a storage container, and transporting the storage container that contains both the cooling device and the object to be kept cold.

In one example, the temperature of the cooling device during the storing step is below -80°C or below -100°C.

The cooling method according to one aspect of the present disclosure includes a step of storing the above-mentioned cooling device and the object to be cooled together in a storage container.

The above configuration or procedure makes it possible to, for example, keep things cold at extremely low temperatures.

FIG. 4 is a diagram showing temperature changes in a cooling agent according to an embodiment of the present invention at different methanol concentrations. FIG. 11 is another diagram showing the temperature change in the ice pack according to the embodiment at different methanol concentrations. FIG. 11 is yet another diagram showing the temperature change in the ice pack according to the embodiment for each concentration of methanol. FIG. 4 is a diagram showing temperature changes for different types of thickeners in a cooling agent according to an embodiment. 5(a), 5(b) and 5(c) are schematic diagrams for explaining application examples of ice packs.

(Overview of ice packs)
The ice pack according to the embodiment of the present disclosure contains methanol (sometimes abbreviated as "MeOH" in the drawings). Examples of such ice packs include the following ice packs:
(1) A cooling agent consisting only of methanol,
(2) A cooling agent consisting only of an aqueous methanol solution, and (3) A cooling agent obtained by adding other components to the cooling agent (1) or (2) above.

The methanol aqueous solution contains water and methanol. For convenience, in the description of this embodiment, the term "methanol aqueous solution" refers to an aqueous solution consisting of only water and methanol, unless otherwise specified. In other words, the methanol aqueous solution does not contain any components other than water and methanol.

The concentration of methanol in the aqueous methanol solution or ice pack may be set as appropriate. In the description of this embodiment, concentrations are in mass percent unless otherwise specified. As described above, in the description of this embodiment, the term aqueous methanol solution refers to a solution containing only water and methanol, and therefore the concentration of methanol in the aqueous methanol solution refers to the proportion of the mass of methanol to the mass (total mass) of water and methanol. For convenience, methanol may be expressed as an aqueous methanol solution with a methanol concentration of 100%.

The concentration of methanol in the aqueous methanol solution contained in the ice packs (1) to (3) above may be, for example, 10% or more and 100% or less, more than 30% and 100% or less, more than 30% and less than 70%, or 40% or more and 60% or less (or 55% or less). These concentration range examples may also be applied to the range of methanol concentration in the ice pack (the mass of methanol in the mass of the ice pack).

Other components in the cooling agent of (3) above can include, for example, one or more additives. Examples of additives include thickeners, preservatives, and colorants. Examples of thickeners include xanthan gum, water-absorbent polymers, and carboxymethylcellulose (CMC).

In the ice pack (3) above, the mass of the methanol aqueous solution may be, for example, 50% or more, 90% or more, or 95% or more relative to the mass of the ice pack. For example, the mass of the thickener may be 0.5% to 5%, 1% to 3%, or 1.5% to 2% relative to the mass of the ice pack. The mass of the preservative may be 0.005% to 0.02% relative to the mass of the ice pack. The mass of the colorant may be 0.05% to 0.2% relative to the mass of the ice pack.

In the description of this embodiment, numerical values that do not include decimals include values rounded to the nearest tenth. For example, a range of 40% or more includes 39.5%. A range of 60% or less includes 60.4%. Numeric values that include decimals include values rounded to the nearest tenth. For example, a range of 0.5% or more includes 0.45%.

(Temperature change of methanol aqueous solution)
An experiment was carried out to examine the temperature change of a frozen aqueous methanol solution (or, from another point of view, the cooling agent of (1) and (2) above). As a result, it was confirmed that the aqueous methanol solution is useful as an ice pack. Specifically, the results are as follows.

The experimental method is as follows. Various concentrations of aqueous methanol solutions were prepared. For each concentration, 400 g of aqueous methanol solution was sealed in a bag made of flexible resin film. The bag containing the aqueous methanol solution was placed in a freezer maintained at -130°C for a sufficient amount of time. This caused the aqueous methanol solution to freeze and its temperature to become equal to the temperature inside the freezer. The bag containing the aqueous methanol solution was then removed from the freezer and placed in a foaming container placed at room temperature. The container had internal dimensions of 300 mm x 200 mm x 120 mm, and was approximately sealed after the bag containing the aqueous methanol solution was placed inside. The temperature of the aqueous methanol solution (not the atmospheric temperature inside the container) was then continuously measured by a thermocouple in contact with the bag containing the aqueous methanol solution from below.

When the methanol concentration was 100%, 25 g of carbon was added to the methanol aqueous solution, and a total of 425 g of ice pack was sealed in the bag. Therefore, the methanol concentration in the methanol aqueous solution was 100%, but the methanol concentration in the ice pack was about 94% (= 400/425). This carbon was added as a nucleating agent to reduce the likelihood of supercooling occurring.

Figures 1 to 3 show the measurement results. In these figures, the horizontal axis t indicates the elapsed time in units of hours (h) and minutes. The vertical axis T indicates the temperature (unit: °C). The multiple lines in the figures show the relationship between the elapsed time and the temperature of the aqueous methanol solution obtained by measurement.

As indicated by the legend, Figure 1 shows results for aqueous methanol solutions with concentrations of 10%, 20%, and 30% methanol. Figure 2 shows results for aqueous methanol solutions with concentrations of 40%, 45%, 50%, and 55% methanol. Figure 3 shows results for aqueous methanol solutions with concentrations of 60%, 65%, 70%, and 100% methanol.

Two measurement targets were prepared for the methanol aqueous solution with a methanol concentration of 50%. For this reason, two measurement results, "MeOH 50% (A)" and "MeOH 50% (B)," are shown in Figure 2. These two are intended to be basically the same conditions, but the conditions, such as the position in the freezer, are different. In other words, these two can be used to consider the error in the measurement results.

The temperature suddenly rises a little after time t has passed 0. This is the measurement when the bag containing the methanol solution is transferred from the freezer to a container, and occurs when the thermocouple is temporarily separated from the bag. Therefore, this temperature change around time t can be ignored.

As shown in Figures 1 to 3, the temperature was maintained at 0°C or below for more than three hours at each concentration. This confirmed that the methanol aqueous solution can be used as a cooling agent.

As shown in Figure 1, when the methanol concentration is 30% or less, the higher the concentration, the longer the time during which the temperature of the aqueous methanol solution is maintained at or below a specified temperature (e.g., -60°C, -70°C, or -80°C) (hereinafter sometimes referred to as the "specified temperature maintenance time"). From another perspective, the higher the concentration, the lower the temperature at the same point in time.

As can be seen from a comparison of Figures 1 and 2, when the methanol concentration increases from 30% to 40%, the time during which the specified temperature is maintained becomes longer. From another perspective, the temperature at the same point in time becomes lower.

As shown in Figure 2, when the methanol concentration is 40% or more and 55% or less, the time during which a specific temperature is maintained (for example, the time during which a temperature of -60°C, -70°C or less, or -80°C or less is maintained) is basically the longest when the concentration is 50% or 55% (when the time t is in the range of 0 to 2 hours and 30 minutes). From another perspective, except for the vicinity of the melting temperature described below, the temperature at the same point in time is basically the lowest when the concentration is 50% or 55%.

As can be seen from a comparison of Figures 2 and 3, when the methanol concentration increases from 55% to 60%, the time for which a given temperature is maintained (for example, the time for which a temperature of -60°C, -70°C or below, or -80°C or below is maintained) becomes shorter. From another perspective, the temperature at the same point in time becomes higher.

As shown in Figure 3, when the methanol concentration is between 60% and 90%, the higher the concentration, the shorter the time for which a specific temperature is maintained (for example, the time for which a temperature of -60°C, -70°C or below, or -80°C or below is maintained). From another perspective, the higher the concentration, the higher the temperature at the same point in time, except near the melting temperature described below. Also, when the methanol concentration is 100%, roughly the same results are obtained as when the methanol concentration is between 60% and 90%.

As shown in region R1 of Figure 2, when the methanol concentration is between 40% and 55%, the temperature of the aqueous methanol solution remains roughly constant. This phenomenon occurs because the aqueous methanol solution absorbs the latent heat generated when changing from a solid to a liquid. The temperature at this time is roughly between -100°C and -90°C (more specifically, -95°C or lower). The melting point of methanol is roughly -96°C. The freezing point of methanol is roughly -65°C.

As shown in Figure 3, when the methanol concentration is 60% and 100%, the temperature of the aqueous methanol solution is maintained roughly constant in the range of -100°C to -90°C, similar to the results shown in Figure 2. However, when the methanol concentration is 60%, compared to Figure 2 (concentration is 40% to 55%), the temperature changes slightly in the range of -100°C to -90°C, and the temperature that is maintained constant is higher.

As shown in Figure 1, when the methanol concentration is 30% or less, the temperature is not maintained constant. Also, as shown in Figure 3, when the methanol concentration is 65% or 70%, the temperature is not maintained constant. However, when the methanol concentration is 30%, 65%, and 70%, the rate of change when the temperature rises in the range below -90°C is smaller than the rate of change thereafter, indicating that latent heat is having an effect.

As shown in Figure 2 (and other figures), the length of time that the temperature of the aqueous methanol solution is kept roughly constant in the range of -100°C to -95°C is longest when the methanol concentration is 50%, followed by 55%. There is no significant difference in the constant temperature when the methanol concentration is in the range of 40% to 55%.

(Effect of thickener)
A cooling agent in which a thickener was added to a methanol aqueous solution (the cooling agent described above in (3)) was prepared, and an experiment similar to that shown in Figs. 1 to 3 was carried out. As a result, it was confirmed that the function of the methanol aqueous solution as a cooling agent could be maintained even if a thickener was added. Specifically, the following is true.

The following three ice packs were prepared for measurement:
(i) an aqueous methanol solution having a methanol concentration of 50%;
(ii) a cooling agent in which xanthan gum is added as a thickener to the aqueous methanol solution of (i) above; and (iii) a cooling agent in which a water-absorbing polymer is added as a thickener to the aqueous methanol solution of (i) above.

The amount of xanthan gum added was 2% of the mass of the ice pack (methanol aqueous solution + xanthan gum) in (ii) above. In other words, of the 400 g of ice pack sealed in the bag, 8 g (= 400 g x 2%) was xanthan gum. The concentration of methanol in the ice pack was 49% (= 392 g x 50% / 400 g).

The amount of water-absorbing polymer added was 1.5% of the mass of the ice pack (methanol aqueous solution + water-absorbing polymer) in (iii) above. In other words, 6 g of the 400 g of ice pack sealed in the bag was water-absorbing polymer. The concentration of methanol in the ice pack was about 49% (= 394 g x 50% / 400 g). The product name "Himloc SS-120" manufactured by Hymo Co., Ltd. was used as the water-absorbing polymer. This water-absorbing polymer is a polyacrylamide-based and anionic polymer.

Figure 4 shows the measurement results and is similar to Figures 1 to 3.

As shown in this figure, even in ice packs to which xanthan gum or water-absorbing polymers were added in typical amounts (for example, 5% or less of the ice pack's mass), a temperature change similar to that of the methanol aqueous solution occurred, and no deterioration in the function of the methanol aqueous solution as an ice pack was confirmed. In addition, in this experiment, when a water-absorbing polymer was used, the function as an ice pack was improved.

However, when the main component of the ice pack is an aqueous methanol solution, not all thickeners can be used. In the inventor's experiments, various thickeners were tried and some did not provide sufficient thickening effect. This is thought to be due to the pH of the aqueous methanol solution. However, at least the thickeners exemplified above can provide a thickening effect. In addition, the pH of the aqueous methanol solution is 7, which means that the aqueous methanol solution is neutral. Therefore, for example, a thickener intended for aqueous solutions with a pH of 6 to 8 may be used.

(Effect of ice packs)
As described above, the ice pack according to this embodiment contains methanol.

The melting point of methanol is, for example, sufficiently lower than the melting point of water (ice). Therefore, by utilizing the latent heat in the temperature range below the melting point of water, it is possible to extend the cooling time in the temperature range below the melting point of water. Although water is given as a comparison, the same can be said for an ice pack made of water to which salt has been added.

Dry ice is an example of an ice pack used to keep things cold in a lower temperature range than the temperature range that ice (water) is intended to keep cold. Dry ice is usually used uncovered, without being enclosed in a bag or other container. Dry ice can keep the temperature of the part of the object it is in contact with at the sublimation temperature (approximately -79°C).

However, dry ice cannot keep something cold below -80°C, which is lower than its sublimation temperature. Dry ice also generates carbon dioxide when it sublimes. Therefore, if the object to be kept cold and dry ice are placed in a sealed container, the pressure inside the container will rise. For this reason, the container containing the object to be kept cold cannot be sealed. Furthermore, the carbon dioxide generated by sublimation expels the atmosphere (e.g., air) around the dry ice and the object to be kept cold. As a result, the atmosphere around the object to be kept cold cannot be kept cold continuously by dry ice. Ultimately, the temperature difference between the part of the object to be kept cold that is in contact with the dry ice and the part that is not in contact with the dry ice is likely to become large.

On the other hand, the methanol-containing ice pack of this embodiment can reduce the inconveniences that arise when dry ice is used as described above. For example, since the melting point of methanol is lower than -80°C, it is possible to perform cooling using latent heat at temperatures below -80°C. The methanol-containing ice pack may be sealed in a container (it does not have to be exposed). The methanol-containing ice pack may be housed in a sealed container together with the object to be kept cold. The methanol-containing ice pack can continuously keep the atmosphere around the ice pack and the object to be kept cold, and keep the object to be kept cold uniformly.

In addition, compared to aqueous solutions containing other alcohols such as ethanol, it is possible to achieve a cooling effect at a relatively low concentration. As a result, it is possible to prepare a cooling agent at a concentration lower than the concentration at which legal restrictions on handling arise (e.g., 60%).

The ice pack may further contain water. The mass of methanol in the mass of water and methanol may be 40% or more. In other words, the concentration of methanol in the aqueous methanol solution in the ice pack may be 40% or more.

In this case, for example, the time required to maintain the temperature of the ice pack at or below a specified temperature (e.g., -60°C, -70°C, or -80°C) is longer than when the concentration is less than 40%. In addition, the use of latent heat makes it easier to maintain the temperature of the ice pack at an extremely low temperature (e.g., -90°C or lower).

In the ice pack, the mass of methanol in the mass of water and methanol may be 40% or more and 60% or less. In other words, the concentration of methanol in the aqueous methanol solution in the ice pack may be 40% or more and 60% or less.

In this case, for example, the temperature of the ice pack can be kept extremely low (for example, below -90°C) by utilizing latent heat. This effect is significant compared to other concentrations.

The mass of water and methanol in the ice pack may be 90% or more (or 95% or more).

In this case, for example, the temperature change of the ice pack is highly dependent on the temperature change of the methanol aqueous solution, so the above-mentioned effects are reliably achieved.

The ice pack may further include xanthan gum. And/or the ice pack may further include a water-absorbing polymer.

In this case, it is possible to impart sufficient viscosity to the ice pack, the main component of which is a methanol aqueous solution, without impairing the cooling properties of the methanol aqueous solution. However, as mentioned above, not all thickeners can impart sufficient viscosity to the methanol aqueous solution.

The temperature of the ice pack may be -80°C or below (at the start of use and/or during use, at least temporarily).

-80°C is lower than the sublimation temperature of dry ice, and therefore lower than the temperature at which an object to be kept cold in contact with dry ice will be kept cold. Therefore, by keeping the temperature of the ice pack lower than -80°C, it is possible to provide a level of coldness that cannot be achieved with dry ice.

The temperature of the ice pack may be -100°C or below (at the start of use and/or during use, at least temporarily).

As can be seen from Figure 2, when the ice pack is cooled to -100°C or below, the latent heat can be used to keep the object cool. As a result, the temperature of the object can be kept at an extremely low temperature (for example, -70°C, -80°C, or -90°C or below) for a longer period of time.

(Examples of ice pack applications)
Hereinafter, application examples of the ice pack according to the present embodiment will be described. Specifically, the following describes ice packs, cargo, transport equipment, transport method, and ice pack method that use the ice pack.

Figure 5 (a) is a perspective view showing an example of a cooling device 3 that uses ice pack 1. Note that part of the cooling device 3 is shown broken away.

The cooling device 3 has an ice pack 1 and an enclosed container 5 in which the ice pack 1 is enclosed. The ice pack 1 is an ice pack according to this embodiment, and contains methanol. The ice pack 3 may be of a type that can be used repeatedly, or of a disposable type. The enclosed container 5 may contain a gas (e.g., air) together with the ice pack 1.

The size, shape, and material of the sealed container 5 may be set appropriately. For example, the sealed container 5 may be a sealed container of various known cooling devices. Specifically, for example, the sealed container 5 may be a bag-shaped container made of a flexible material (such as resin), or a hard-type container (as shown in the example) made of a non-flexible material (such as resin). For example, the sealed container 5 may not have an injection port (the ice pack 1 cannot be taken out without destroying the sealed container 5), or may have an injection port blocked by a cap as in the example shown in the figure. For example, the shape of the sealed container 5 may be a roughly rectangular parallelepiped (as shown in the example), or may have a unique shape depending on the application. For example, the volume of the sealed container 5 (maximum volume in the case of a flexible container) may be 10 ml or more and 1 liter or less.

Figure 5(b) is a cross-sectional view showing an example of cargo 11 using ice pack 1.

The cargo 11 includes, for example, one or more objects 13 to be kept cold, one or more cooling devices 3, and a box 15 that contains them all. The box 15 is an example of a storage container.

Examples of the object to be kept cold include food. Examples of the food include frozen foods, frozen sweets, fresh sweets, dairy products, and fresh foods. Frozen foods are foods that are frozen for the purpose of long-term storage, and before freezing, they may be unheated, heated, uncooked, or cooked. Examples of frozen sweets include ice cream. Examples of fresh sweets include cake. Examples of dairy products include yogurt. Examples of fresh foods include fresh fish (seafood), meat, and fruits and vegetables. In FIG. 5(b), a cup of ice cream is shown as an example of the object to be kept cold 13.

In addition to food and beverages, examples of objects to be kept cold include organs for transplantation and vaccines (containers containing organs for transplantation or vaccines). In recent years, the coronavirus vaccine, which needs to be kept at extremely low temperatures (e.g., -70°C or lower), has been a hot topic of discussion as a vaccine, and the coronavirus vaccine may be considered as an object to be kept cold. The term "cold storage" is generally used for food products, but as can be understood from the above examples, in this disclosure, objects to be kept cold are not limited to food products.

The size, shape, and material of the box 15 may be set as appropriate, and for example, various known boxes may be used. Representative examples include a relatively small box (e.g., 1 m or less x 1 m or less x 1 m or less) made of polystyrene foam or cardboard, and a cooler box (ice box) that combines a plastic case with insulating material. The material of the box 15 may be one with relatively high insulating properties, or one with low insulating properties.

The positions of the object 13 to be kept cool and the cooling device 3 within the box 15 may also be set appropriately. For example, the cooling device 3 may be located to the side of the object 13 to be kept cool (as in the illustrated example), above it, below it, or in a combination of two or more of these positions. Depending on the type of object 13 to be kept cool, its packaging, and/or the configuration of the box 15, it may be possible to directly house the ice pack 1 in the box 15 (without enclosing it in the enclosure 5) rather than housing the cooling device 3 in the box 15.

Figure 5 (c) is a side view showing an example of a transport device 21 that uses ice pack 1.

The transport equipment 21 has, for example, one or more cargoes 11 and one or more containers 23 that store the cargoes 11. Note that the containers 23 are also an example of a storage vessel, similar to the boxes 15.

Examples of transport equipment 21 include automobiles (as shown in the example), aircraft, trains, ships, and motorcycles. In FIG. 5(c), a refrigerated or freezer vehicle having an attached container 23 is shown.

The arrangement of the cargo 11 within the container 23 may be set as appropriate. Also, instead of storing the cargo 11 in the container 23, the object to be refrigerated 13 and the cooling device 3 may be directly stored in the container 23 (without being stored in a box 15). Depending on the type of object to be refrigerated 13, its packaging and/or the configuration of the container 23, it may also be possible to store the ice pack 1 directly in the container 23 (without being enclosed in an enclosure 5).

Here, the box 15 and its contents are described as cargo 11. In other words, the cargo is exemplified as being relatively small, so that it can be carried (manually) by one person or a small number of people. However, the cargo may be larger than this size. For example, in FIG. 5(c), the container 23 is shown attached to an automobile, but it may also be something that is loaded onto and unloaded from a container ship, truck, and/or train, and this container and its contents may be considered to be cargo.

The storage vessel (box 15 or container 23) may simply be insulated, or may be actively kept at a low temperature by a cooling device such as a chiller. In the latter case, the temperature of the object to be cooled is maintained at a temperature intermediate between the target temperature of the cooling device and the temperature of the ice pack, which is lower than the target temperature, for example.

Figures 5(a) to 5(c) also show a transportation method and a cold storage method according to the embodiment. The transportation method includes a step of cooling the cold storage device 3 (Figure 5(a)), a step of storing the cold storage device 3 and the object to be kept cold 13 together in a box 15 (Figure 5(b)), and a step of transporting the box 15 storing the cold storage device 3 and the object to be kept cold 13 together (Figure 5(c)). The cold storage method includes a step of cooling the cold storage device 3 (Figure 5(a)), and a step of storing the cold storage device 3 and the object to be kept cold 13 together in a box 15 (Figure 5(b)). The cold storage method may simply perform cold storage without transportation.

The cooling device 3 (ice pack 1) may be at an appropriate temperature, for example, when cooling of the cooling device 3 is completed, or when use of the cooling device 3 begins (for example, when it is packed together with the object to be cooled 13) or immediately before that (for example, within 10 minutes of beginning use). For example, the temperature of the cooling device 3 may be -50°C or lower, -70°C or lower, -80°C or lower, below the melting point of methanol, -100°C or lower, or -130°C or lower.

To cool the cooling device 3 to an extremely low temperature, for example, the "Ultra-Low Temperature Chiller Cold Wave" manufactured by ADD Co., Ltd. may be used. This ultra-low temperature chiller uses a multi-stage evaporator and a mixed refrigerant to cool the supplied gas (for example, air, freon gas, liquid nitrogen, or argon gas) to a temperature of about -130°C. Then, for example, by supplying the gas cooled by the chiller around the cooling device 3, the cooling device 3 (cooling agent 1) can be cooled to the various temperatures exemplified above.

Just to clarify, a chiller includes the concept of a freezer. Although not specifically illustrated, a chiller has, for example, as its basic components, a compressor that compresses a refrigerant, a condenser that cools the compressed refrigerant, an expansion valve that reduces the pressure of the cooled refrigerant before sending it out, and an evaporator that cools the object to be cooled (the ice pack or the gas supplied around the ice pack) with the reduced pressure refrigerant. Chillers may be installed, for example, at locations where the objects to be cooled are produced or wholesaled, or at each business office of a company that handles home delivery.

The technology disclosed herein is not limited to the above embodiments and may be implemented in various ways.

In the embodiment, the methanol concentration in the methanol aqueous solution is exemplified as 10% or more and 100% or less. However, the methanol concentration may be less than 10%. Even in this case, for example, by including even a small amount of methanol, which has a lower melting point than water, in the ice pack, the cooling effect is improved compared to an ice pack consisting of only water.

1... ice pack, 3... ice pack, 5... sealed container, 11... cargo, 13... object to be kept refrigerated, 21... transportation equipment.

Claims (9)

A cooling agent containing methanol and water ,
the mass of the methanol is 40% or more and 55% or less of the mass of the water and the methanol;
The mass of the water and the methanol in the ice pack is 90% or more,
The methanol solution is solidified at a specified temperature of -100°C or lower.
If heat is absorbed from the above-mentioned predetermined temperature state, the temperature will become constant in the range of -100°C to -95°C due to the absorption of latent heat.
Ice packs . The ice pack according to claim 1, further comprising xanthan gum. Further comprising a water-absorbing polymer,
The ice pack according to claim 1 . The ice pack according to any one of claims 1 to 3 ,
A container in which the cooling agent is enclosed;
A cooling device having the above structure. The cooling device according to claim 4 ,
An object to be kept cold;
A storage container that stores both the cooling device and the object to be cooled;
Cargo that has the following characteristics: The cooling device according to claim 4 ,
An object to be kept cold;
A storage container that stores both the cooling device and the object to be cooled;
A transportation device having the above structure. A step of storing both the cooling device according to claim 4 and an object to be cooled in a storage container;
A step of transporting the storage container that contains both the cooling device and the object to be cooled;
A transportation method having the above construction. The transportation method according to claim 7 , wherein the temperature of the cooling device is −100° C. or lower in the storing step. A cooling method comprising the step of housing both the cooling device according to claim 4 and an object to be cooled in a housing container.

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