JP2011021807A - Heat accumulator and cooling method using the heat accumulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat accumulator capable of shortening cooling time, preventing drying and deterioration of a cooled object and enhancing energy efficiency by effectively storing and emitting heat. <P>SOLUTION: The heat accumulator 10 includes: a heat insulating case 12 forming a space 16 therein and having an inlet 12a and an outlet 12a; a thermal storage medium 20 arranged within the space 16, having a high thermal conductivity body with higher thermal conductivity and heat capacity than those of air and enabling heat storage; and a fan 18 arranged in the vicinity of the inlet 12a or the outlet 12a and promoting flowing of cooling air from the inlet 12a toward the outlet 12a. The cooling air can be made to flow in the thermal storage medium 20. The fan 18 suppresses flowing of the cooling air from the inlet 12a toward the outlet 12a up to a point near the freezing point of the cooled object, and promotes the flowing of the cooling air from the inlet 12a toward the outlet 12a upon arrival at the point near the freezing point of the cooled object. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat storage device used for rapid cooling of an object to be cooled such as food or maintaining the temperature of a temperature control space, and a cooling method using the heat storage device.

  As a cooling method for rapidly cooling an object to be cooled, a method described in Patent Document 1 proposed by the present inventor is known.

  In this patent document 1, drying and degeneration of an object to be cooled can be prevented while cooling and degassing problems such as a conventional vacuum cooling system, a blast chiller system, and an electromagnetic induction system cannot be avoided. The cooling method and cooling device which can shorten time are proposed.

  That is, in Patent Document 1, the cooling process is performed by precooling until the object to be cooled reaches a predetermined temperature just before reaching the temperature range where the object to be cooled is most likely to deteriorate in the vicinity of the solidification point of the object to be cooled or the physical property of the object to be cooled. In the pre-cooling step, the boundary between the cold insulation chamber and the cooling chamber is shielded by a partition member, and in the rapid freezing step, the partition member is at least one of the boundaries. The part is opened.

  More specifically, as shown in FIG. 15, the cooling device 100 is installed in the space 116 surrounded by the heat insulating wall body 112, the cold insulation chamber 122 in which the cooler 118 is installed, and the object to be cooled. A partition member 130 is provided at the boundary between the cold insulation chamber 122 and the cooling chamber 124 separately from the cooling chamber 124. In the pre-cooling step, by blocking the boundary with the partition member 130, the air flow between the cold insulation chamber 122 and the cooling chamber 124 is suppressed to prevent drying of the object to be cooled. By opening the partition member 130, the flow of air between the cold insulation chamber 122 and the cooling chamber 124 is promoted, and the time required to reach the target refrigeration temperature can be shortened as a whole.

  Further, in the pre-cooling process, the cool air generated in the cooler 118 in the cool storage chamber 122 is stored in the heat storage material 120, and in the quick freezing process, the partition member 130 is opened so that the cool air stored in the heat storage material 120 is stored in the cooling chamber 124. Liberated.

Japanese Patent No. 4260873

  In the vicinity of the freezing point of the object to be cooled, the heat capacity increases drastically, and an amount of heat about 80 times that of the freezing point or higher is required. The ice crystal zone, which is the temperature zone near the freezing point, is the temperature range in which the object to be cooled is most likely to deteriorate in terms of physical properties, and when the time passing through this temperature zone increases, ice crystals grow and the structure of the object to be cooled Destroys. If the temperature zone can be passed in a short time, the growth of ice crystals can be prevented, the ice crystals can be made smaller, and the structure of the object to be cooled can be prevented from being destroyed. And if this ice crystal zone with a large heat capacity can be passed in a short time, the time required for the whole cooling can also be shortened.

  The present inventor can reduce the cooling time, prevent drying / deterioration of the object to be cooled, and increase the energy efficiency by further effectively storing and releasing the heat during the cooling. In view of this, the present invention has been completed by conceiving a heat storage device suitable for achieving this object. The inventor of the present invention has also conceived a heat storage device capable of achieving energy efficiency by storing and releasing heat even during temperature adjustment, and has completed the present invention.

That is, the invention of claim 1 is a heat storage device installed in a cooling device that generates cooling air to cool an object to be cooled,
A heat insulating case that forms a space inside and has an inlet and an outlet;
A heat storage material capable of storing heat, including a high thermal conductivity body disposed in the space and having a higher thermal conductivity and heat capacity than air; and
A flow facilitating means disposed near the inflow port or the outflow port to promote the flow of cooling air from the inflow port toward the outflow port;
With
The heat storage material is capable of circulating the cooling air,
The flow promoting means suppresses the flow of cooling air from the inlet to the outlet from the start of cooling to the vicinity of the freezing point of the object to be cooled, and when it reaches the vicinity of the freezing point of the object to be cooled, it directs from the inlet to the outlet. It is characterized by promoting the circulation of cooling air.

  The invention according to claim 2 is characterized in that the high thermal conductivity body according to claim 1 has a large number of metal particles, and a gap through which air can flow is formed between the metal particles.

  According to a third aspect of the present invention, the heat storage material according to the second aspect of the present invention has a metal case that contains metal particles, and the metal case allows passage of the cooling air while preventing the passage of metal particles. A vent is provided.

  The invention according to claim 4 is characterized in that the heat storage material according to any one of claims 1 to 3 is detachable from the heat insulating case.

The invention according to claim 5 is a heat storage device installed in a cooling device that generates cooling air to cool an object to be cooled, and forms a space therein, and has an inlet and an outlet. A heat insulating case, a heat storage material that is disposed in the space and includes a high thermal conductivity body having a higher thermal conductivity and heat capacity than air, and is disposed in the vicinity of the inlet or the outlet. A cooling method for cooling an object to be cooled in the cooling device using a heat storage device provided with a flow promoting means for promoting the flow of cooling air from the inlet to the outlet,
From the start of cooling of the object to be cooled to the vicinity of the freezing point, a first cooling step for suppressing the flow of cooling air from the inflow port through the heat storage material toward the outflow port by the flow promoting means,
A second cooling step for accelerating the flow of cooling air from the inlet through the heat storage material toward the outlet when the vicinity of the freezing point of the object to be cooled is reached;
It is characterized by providing.

  According to a sixth aspect of the present invention, in the cooling method according to the fifth aspect, before the first cooling step, the circulation of the cooling air that passes through the heat storage material from the inflow port to the outflow port by the flow promoting means is promoted. And the pre-cooling process which cools the temperature of the said thermal storage material below to the freezing point of a to-be-cooled object is characterized.

  The invention according to claim 7 is the cooling method according to claim 5 or 6, further comprising a step of feeding the object to be cooled into the cooling device, the step of directing the outlet to the object to be cooled. It is characterized by.

  Invention of Claim 8 is the cooling method of any one of Claim 5 thru | or 7, When the temperature inside the said thermal storage apparatus becomes the same as the temperature outside a thermal storage apparatus after a 2nd cooling process. And a third cooling step for suppressing the flow of cooling air from the inflow port through the heat storage material toward the outflow port by the flow promoting means.

  The invention according to claim 9 is the cooling method according to any one of claims 5 to 8, wherein when the temperature outside the heat storage device reaches a temperature lower than the freezing point of the object to be cooled by a predetermined temperature. The method further comprises a step of promoting the circulation of the cooling air that passes through the heat storage material from the inflow port to the outflow port by the flow promoting means.

The invention according to claim 10 is a heat storage device arranged in a temperature control space adjusted to a set temperature by intermittent operation of an actuator,
A heat insulating case that forms a space inside and has an inlet and an outlet;
A heat storage material capable of storing heat, including a high thermal conductivity body disposed in the space and having a higher thermal conductivity and heat capacity than air; and
A flow facilitating means disposed near the inflow port or the outflow port to promote the flow of temperature-controlled air from the inflow port toward the outflow port;
With
The heat storage material is capable of circulating the temperature-controlled air,
The flow promoting means suppresses the flow of temperature-controlled air from the inlet to the outlet when the temperature of the temperature-controlled space becomes the first allowable limit temperature and the actuator starts to operate. When the temperature reaches the second allowable limit temperature before reaching the first allowable limit temperature, the circulation of the temperature-controlled air from the inlet to the outlet is promoted.

The invention according to claim 11 is a heat storage device installed in a cooling device that generates cooling air to cool an object to be cooled,
A heat insulating case that forms a space inside and has an inlet and an outlet;
A heat storage material capable of storing heat, including a high thermal conductivity body disposed in the space and having a higher thermal conductivity and heat capacity than air; and
A flow facilitating means disposed near the inflow port or the outflow port to promote the flow of cooling air from the inflow port toward the outflow port;
The heat storage material is capable of circulating the cooling air.

  According to the heat storage device and the cooling method using the heat storage device according to the present invention, when a large amount of heat is not required for cooling the object to be cooled until the object to be cooled reaches the vicinity of the freezing point, the flow promoting means is connected from the inlet to the outlet. By suppressing the flow of cooling air toward the heat storage, heat storage is maintained by the heat storage material in the heat insulation case, and when the object to be cooled reaches the vicinity of the freezing point, the flow promoting means moves the cooling air from the inlet to the outlet. By promoting the circulation, the amount of heat stored in the heat storage material can be released. As a result, the freezing point where the heat capacity increases drastically can be passed in a short time, enabling rapid cooling, preventing deterioration of the object to be cooled, and providing high resilience.

  Since the amount of heat can be confined in the heat storage material in the heat insulation case, heat can be stored effectively.

  By having a large number of metal particles as the heat storage material, the cooling air can pass through gaps formed between the large number of metal particles, and heat exchange between the cooling air and the metal particles can be performed efficiently.

  In addition, the heat storage material has a metal case that contains metal particles, and the metal case is provided with a ventilation portion that prevents the passage of the metal particles but allows the cooling air to flow. Loss can be prevented.

  By making the heat storage material detachable from the heat insulating case, the heat storage material can be used for cleaning, and the heat storage device can be kept hygienic.

  Moreover, in the cooling method by this invention, by providing the pre-cooling process which pre-cools a heat storage material, heat storage can be performed to a heat storage material previously, and a to-be-cooled object can be cooled more efficiently. Furthermore, by providing a charging process in which the outlet of the heat storage device is directed to the object to be cooled and the object to be cooled is input, the amount of heat is effectively supplied to the object to be cooled when the amount of heat stored in the heat storage material is released. be able to. Furthermore, after the second cooling step, when the temperature inside the heat storage device becomes the same as the temperature outside the heat storage device, the cooling air that passes through the heat storage material from the inflow port by the flow promoting means toward the outflow port By providing the 3rd cooling process which suppresses distribution | circulation, after the calorie | heat amount stored by the heat storage apparatus was discharge | released, cooling air can be exclusively applied to cooling of a to-be-cooled object, and cooling time can be shortened. Furthermore, when the temperature outside the heat storage device becomes a predetermined temperature lower than the freezing point of the object to be cooled, the circulation of the cooling air that passes through the heat storage material from the inflow port to the outflow port by the flow promoting means is promoted. By further providing the step, when the object to be cooled is sufficiently cooled, the heat storage material can be stored again to prepare for the next cooling cycle.

  Or, by arranging the heat storage device in the temperature control space that is adjusted to the set temperature by the intermittent operation of the actuator, the heat storage device stores the excess heat during operation of the actuator, and it becomes insufficient when the actuator is not operating By releasing the amount of heat from the heat storage device, the pause time in the intermittent operation of the actuator can be lengthened, and energy efficiency can be improved. Since the amount of heat can be confined in the heat storage material in the heat insulation case, heat can be stored effectively.

It is a perspective view of the heat storage apparatus by this invention. It is sectional drawing of the thermal storage apparatus by this invention. It is sectional drawing seen from the top which represents 1st Embodiment of the thermal storage apparatus by this invention, and shows the internal structure of the state installed and used in the cooling device. It is sectional drawing seen from the side which shows the internal structure of the state by which the thermal storage apparatus by this invention was installed and used in the cooling device. It is a graph showing the time change of various temperatures in a cooling process. It is sectional drawing showing the state of prior measurement in the cooling device of FIG. 2A shows a second embodiment of a heat storage device according to the present invention, and shows an internal structure in a used state installed in a temperature holding device, (a) is a sectional view seen from above, and (b) is seen from the side. It is sectional drawing. It is a cross-sectional view showing the modification 1 of the heat storage apparatus by this invention. It is a longitudinal cross-sectional view showing the modification 1 of the thermal storage apparatus by this invention. It is sectional drawing seen along the 10-10 line of FIG. It is sectional drawing showing the modification 2 of the thermal storage apparatus by this invention. It is sectional drawing showing the modification 3 of the thermal storage apparatus by this invention. It is sectional drawing showing the modification 4 of the thermal storage apparatus by this invention. (A) is an Example, (b) is a graph showing the relationship between the center temperature of the to-be-cooled object and time in the vicinity of the freezing point vicinity of a comparative example. (A) which shows the internal structure of the conventional cooling device is sectional drawing seen from upper direction, (b) is sectional drawing seen from the side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments do not limit the present invention.

(First embodiment)
As shown in FIG.1 and FIG.2, the thermal storage apparatus 10 by this invention has the heat insulation case 12 comprised from foaming material etc. and making a substantially rectangular parallelepiped shape. The heat insulating case 12 has openings 12a and 12a formed on two opposing surfaces thereof, respectively, and a door 12b is provided on a part of one surface thereof, and the openings 12a and 12a facing each other with the door 12b closed. Thus, a closed space 16 that can communicate with the outside is formed. One or more openings 12a can be provided.

  A fan 18 as a flow promoting means is attached to one or both of the openings 12a and 12a, and the fan 18 takes in cooling air from outside into the space 16, or a space. 16 acts as an exhaust fan for sending cooling air from the inside to the outside. The fan 18 generates a one-way air flow that flows from the outside through the space 16 through the opening 12a serving as one inflow port to the outside through the opening 12a serving as the other outflow port.

  The fan 18 is connected to a controller 70 (see FIGS. 3 and 4), and the number of rotations is controlled by a control signal from the controller 70.

  A heat storage material 20 is disposed in the heat insulating case 12. The heat storage material 20 can be taken into and out of the space 16 through the door 12b of the heat insulating case 12 so that it can be attached to and detached from the heat insulating case 12. In the state in which the heat storage material 20 is disposed, a gap may be formed between the surface of the heat storage material 20 facing each opening 12a and the opening 12a, and thereby air taken in from the opening 12a may be formed. The heat storage material 20 is rectified to enter the heat storage material 20, and the heat storage material 20 can exit from the rectification state. For example, the distance between the heat storage material 20 and the opening 12 a may be the same size as the thickness of the heat storage material 20. On the other hand, the other surface of the heat storage material 20 is preferably in close contact with the wall surface of the heat insulation case 12 in the space 16 so that there is no gap.

  The heat storage material 20 includes a metal case 22 and a large number of high thermal conductivity bodies 24 sealed in the metal case 22. At least a part of the surface of the metal case 22 facing the opening 12a of the heat insulating case 12 is a porous wall surface 22a as a ventilation portion. The porous wall surface 22a can be made of a metal such as punching metal, wire mesh, mesh or the like.

  As a large number of high thermal conductivity bodies enclosed in the metal case 22, for example, metal particles 24 can be used. Although the metal particles 24 overlap a plurality of layers in the metal case 22, due to the shape, a gap through which air can flow is formed between the adjacent metal particles 24.

  The shape of the metal particles 24 is not necessarily a true sphere, and may be an ellipsoid or some distortion, and may be a cylinder, a rectangular parallelepiped, a polyhedron, or the like. Preferably, the shape is such that there are few protrusions and a large surface area can be secured. The metal particles 24 have a diameter (or a minimum passing dimension) that cannot pass through the porous wall surfaces 22a, 22a, and cannot be dropped or lost from the heat storage device 10. If the diameter of the metal particle 24 (or the maximum dimension for passing) is too small, it is difficult to form a gap through which air can flow, and if it is too large, the contact area between the adjacent objects becomes small. The thickness may be about 2 mm to 10 mm, preferably about 3 to 8 mm. Further, the size or shape of the metal particles 24 need not be the same for all the metal particles 24, and metal particles 24 having different sizes or different shapes may be mixed. Alternatively, the metal particles 24 may be filled with an antifreeze liquid (not frozen at 0 ° C., hereinafter the same) inside the metal hollow body.

  The metal particles 24 are non-flowing solids that do not flow due to air flowing in the space 16 (flow rate: several m / s to 15 m / s, preferably about 0 to 6 m / s). Although a large number of metal particles 24 are constrained in the metal case 22, it is preferable that the metal particles 24 have a certain degree of freedom without being constrained in the metal case 22. It is preferable that a free arrangement can be made within the case 22.

  Both the metal case 22 and the metal particles 24 are made of a high thermal conductivity material having a high thermal conductivity and a large heat capacity. Specifically, the high thermal conductivity material can be selected from aluminum, copper, brass, gold, silver, or alloys thereof.

  The above heat storage device 10 is installed in a cooling device 40 that generates cooling air, such as a known freezer. As shown in FIGS. 3 and 4, the cooling device 40 includes a heat insulating wall body 42 and a door 44 formed on one side surface of the heat insulating wall body 42. A chamber 46 that is adiabatically isolated from the outside is defined.

  A cooler 48 composed of an evaporator or the like that generates cooling air and a fan 49 disposed in front of the cooler 48 are installed in a part of the interior 46. A to-be-cooled object support unit 50 is placed. The to-be-cooled object support unit 50 may be a movable wagon as illustrated, or may be a tray that is detachably mounted on a guide rail fixed to the interior 46.

  Further, the heat storage device 10 is arranged in the other part of the interior 46. Preferably, it is good to arrange | position so that the opening 12a used as the outflow port of the thermal storage apparatus 10 may face toward the to-be-cooled object P. FIG. One or a plurality of heat storage devices 10 can be arranged discretely or stacked or arranged side by side as shown. Further, the heat storage device 10 can be supported by the legs 14 as appropriate. The legs 14 may be appropriately provided with casters so that the heat storage device 10 itself can be easily inserted into and removed from the interior 46.

  The refrigerant circulation circuit 60 that passes through the cooler 48 includes a condenser 62, a refrigerant tank 64, a compressor 66, and an expansion valve 68 arranged outside the warehouse. The rotation of the compressor 66 can be controlled by the controller 67 and the inverter 69, and the operation of the compressor 66 can be controlled to change the refrigerant temperature according to the type of the object to be cooled. It is good to be.

  Next, in this embodiment, a cooling method for cooling an object to be cooled will be described. In this cooling method, the object to be cooled is cooled while controlling the rotational speed of the fan 18 of the heat storage device 10. The rotational speed of the fan 18 is controlled depending on the state of the object to be cooled, and more specifically, contained in the object to be cooled from the cooling start temperature to the point before the object reaches the freezing point or until it reaches the freezing point. The liquid phase region where the moisture is in the liquid phase state (first cooling step), the region near the freezing point where the moisture contained in the object to be cooled changes from the liquid phase to the solid phase (second cooling step), mainly the object to be cooled The number of rotations of the fan 18 is controlled in accordance with the solid phase region (third cooling step) in which the contained moisture becomes a solid phase (ice). Hereinafter, the cooling method and the control will be described with reference to FIG.

(Pre-cooling process)
The inside 46 of the cooling device 40 is cooled in advance. And in the heat storage apparatus 10 previously installed in the store | warehouse | chamber 46, the fan 18 is driven at high speed, the cooling air produced | generated by the cooler 48 is flowed in into the heat storage apparatus 10 from one opening 12a, and a heat storage material. 20 is allowed to pass through in a rectified state, and a slight gap formed between a large number of metal particles 24 in the heat storage material 20 is passed through to exchange heat with the metal particles 24. Since the metal particles 24 are made of a metal having good heat conductivity, heat exchange between the metal particles 24 and the cooling air is performed, and the animal heat material 20 made of the metal particles 24 is cooled. After rotating the fan 18 for a certain period of time, the heat storage material 20 is stored by setting the rotation speed of the fan 18 to a low speed (including 0), and low-temperature heat is maintained in the heat insulating case 12. The
At this time, the temperature of the heat storage material 20 or the space 16 of the heat storage device 10 is lower than the freezing point of the object P to be cooled (for example, a temperature lower by 10 ° C. or more).

(Subject to be cooled)
The object to be cooled is placed on the object to be cooled support unit 50, the door 44 is opened, and the container 46 is put in. The object to be cooled can be put in an unwrapped state or packaged in a hard synthetic resin container, a soft synthetic resin film, or a soft synthetic resin bag. The cooling start temperature at the time of charging is arbitrary and can be set to a temperature of 0 to 100 ° C. After the object to be cooled is charged, the door 44 is closed. In the case where the object to be cooled is not one having a property of being scattered by the wind (for example, powdery or granular), the object to be cooled may be in a position facing the outlet 12 a of the heat storage device 10.

(Liquid phase process)
Immediately after the charging process, the internal temperature rises, but the rotation speed of the fan 18 of the heat storage device 10 is maintained at a low speed (including 0), and the flow rate of cooling air passing through the heat storage device 10 is small, and the passage is suppressed. Therefore, the heat storage device 10 holds the low-temperature heat stored in the pre-cooling step, and the temperature of the heat storage material 20 or the space 16 is kept lower than the freezing point of the object P to be cooled.

  In this step, as shown in FIG. 5, any one selected from the center temperature of the object to be cooled, the temperature of the interior 46, the surface temperature of the object to be cooled, and the temperature of the refrigerant passing through the cooler 48 is selected. Cooling should be performed so that the difference from the temperature is as small as possible. Preferably, cooling is performed while controlling the temperature or flow rate of the refrigerant by the controller 67 so that the center temperature of the object to be cooled and the surface temperature of the object to be cooled become zero as much as possible. Preferably, except for the initial stage, the difference between the center temperature and / or surface temperature of the object to be cooled and the temperature of the interior 46 is constant (for example, a temperature difference of 10 ° C. to 40 ° C.), or the center of the object to be cooled Cooling may be performed so as to have a process in which the difference between the temperature and / or the surface temperature and the refrigerant temperature is constant (for example, a temperature difference of 30 to 60 ° C.).

  That is, as described above, the temperature difference between the center temperature and the surface temperature is 0 immediately after the introduction of the object to be cooled at the cooling start temperature, and thereafter the surface temperature becomes lower. Then, it is preferable to control the temperature or flow rate of the refrigerant so that the temperature difference becomes substantially zero. For example, in the liquid phase process, up to a predetermined temperature (for example, around + 5 ° C.), the process of reducing the temperature difference between the center temperature of the object to be cooled and the surface temperature, and below the predetermined temperature (for example, + 5 ° C. or lower) The process may be divided into two processes so that the temperature difference between the center temperature of the object to be cooled and the surface temperature is substantially zero.

  In the above liquid phase region process, the supply of cold air to the object to be cooled utilizes heat radiation from the portion facing the cooler 48 and natural convection to the interior 46. The heat transfer rate is proportional to the temperature difference, and since this temperature difference is small in the liquid phase process, cooling takes place over a relatively long time.

  Since cooling is performed at a low speed so as to reduce the temperature difference Δt between the center temperature and the surface temperature of the object to be cooled, moisture evaporation from the object to be cooled is prevented. This is because moisture does not move between the center temperature of the object to be cooled and the surface temperature. Furthermore, since the inside 46 is maintained at high humidity, the object to be cooled is further prevented from drying.

Until the freezing point is reached, the amount of heat required to lower the temperature of the object to be cooled is small. When considering the heat quantity Q required in this liquid phase region process, the heat quantity Q is Q∝Δt, and since Δt is small, Q is small.
Thus, the object to be cooled is cooled to a temperature in the vicinity of the freezing point, that is, in the vicinity of the temperature range where the physical properties are most likely to deteriorate due to the liquid phase process.

(Process near freezing point)
When the vicinity of the freezing point of the object to be cooled is reached, the rotational speed of the fan 18 is set to a high speed. Therefore, the flow rate of the air passing through the heat storage device 10 increases and the passage is promoted. When the cooling air passes through the heat storage material 20, it releases the low-temperature heat stored in the large number of metal particles 24 filled in the heat storage material 20 at a stretch, and generates the amount of heat necessary for the object to be cooled to freeze. compensate. As a result, the object to be cooled can pass through the ice crystal zone in a short time.

  In the vicinity of the freezing point of the object to be cooled, the heat capacity increases drastically, and an amount of heat about 80 times that of the freezing point or higher is required. As is well known, an ice crystal zone, which is a temperature zone near the freezing point, is a temperature region in which the object to be cooled is most likely to deteriorate in terms of physical properties. When the time for passing through this temperature zone becomes longer, ice crystals grow and the structure of the object to be cooled is destroyed. If the temperature zone can be passed in a short time, the growth of ice crystals can be prevented, the ice crystals can be made smaller, and the structure of the object to be cooled can be prevented from being destroyed.

  By supplementing the necessary amount of heat with the heat accumulator 10, the ice crystal band can be passed in a short time, and the time required for the entire cooling can be shortened.

  When the opening 12a serving as the outlet of the heat storage device 10 is arranged to face the object P to be cooled, the low-temperature heat stored in the heat storage device 10 is directly directed to the object to be cooled. Thus, low temperature heat is supplied to the object P to be cooled.

  Ideally, it should pass through the vicinity of the freezing point at 3 minutes / ° C. or less. For this reason, the heat capacity and precooling temperature of the heat storage material 20 are determined so as to match the heat capacity determined from the total mass and specific heat of the object to be cooled. When the temperature of the heat storage material rises and the temperature of the heat storage material 20 or the space 16 of the heat storage device 10 becomes equal to the internal temperature, the rotation speed of the fan 18 is set to a low speed (including 0), The release of low temperature heat is stopped.

(Solid phase process)
After the object to be cooled freezes after passing through the ice crystal zone, the heat capacity for cooling the object to be cooled is further smaller than that in the liquid phase region, and is about ½ of that. The rotation speed of the fan 18 is set to a low speed. Thereby, the cooling air can be exclusively applied to the cooling of the object to be cooled to shorten the cooling time.

  When the cooling cycle for another object to be cooled is continuously repeated, when the temperature of the object to be cooled P becomes sufficiently lower than the freezing point (for example, −10 ° C. from the freezing point), the fan 18 is raised again for a predetermined time. It is preferable to drive at a speed and introduce cooling air into the heat storage device 10 to perform heat storage, whereby the next cooling process can be started from the object input process without a pre-cooling process.

(Preliminary measurement)
The flow rate of the cooling air passing through the heat storage device 10 described above is switched by the controller 70 when the object to be cooled reaches just before or near the freezing point and when the temperature in the heat storage device 10 becomes equal to the internal temperature. It is done. The condition for performing the switching by the controller 70 can be that the elapsed time from the start of cooling has passed a predetermined time, or that the temperature at an arbitrary point has been cooled to a predetermined temperature. The time or the predetermined temperature can be specified by prior measurement.

  Specifically, as shown in FIG. 6, any reference point of the heat storage device 10 (the temperature of the space 16 on the inlet side of the heat storage material 20, the temperature of the space 16 on the outlet side of the heat storage material 20, or The temperature sensor 72-1 to 72-5 is attached to an arbitrary reference point of the heat storage material 20) or an arbitrary reference point in the storage 46 and the inside or outside surface portion of the object to be cooled, and these measurement data are collected by the analyzer 74. With the fan 18 set at a low speed, the object to be cooled is cooled from the cooling start temperature, and the passage of time between the internal temperature or the external temperature of the object to be cooled and the temperature of the reference point is measured.

  Since the freezing point of the object to be cooled is known, it is possible to determine whether the temperature near the freezing point has passed or passed through the freezing point from the internal or external temperature of the object to be cooled. Or the conditions which the controller 70 switches can be calculated | required by calculating | requiring the temperature of a reference | standard point.

  In the actual cooling process, when the temperature at the reference point is used as the switching condition, the temperature signal from the temperature sensor is sent to the controller, leaving the temperature sensor 72-1, 72-2, or 72-3 at the reference point. When the elapsed time is used as a switching condition, a timer is provided in the controller 70. When the switching condition is satisfied, the controller 70 can control the motor of the fan 18 using an inverter as necessary. The temperature signal from the temperature sensor is also supplied to the controller 67, and the temperature and / or flow rate of the refrigerant is controlled.

  Alternatively, the temperature sensors are left at the reference point provided in the heat storage device 10 and the reference point provided in the warehouse 46, and the temperature signals from these temperature sensors are supplied to the controller 70, and the difference between these temperature signals. Thus, the controller 70 can also control the motor of the fan 18.

  As described above, according to the present invention, the heat storage material 20 including a high thermal conductivity material such as the metal particles 24 is used. Since the metal particles 24 have high thermal conductivity, heat exchange with cooling air is efficient. It performs well and can store heat effectively.

  The metal thermal conductivity is compared to air, antifreeze, and water as follows.

Thus, aluminum, metals such as copper, having 10 ⁴ times the air, water, a high thermal conductivity 300 times or more liquid like ethanol. Therefore, rapid cooling can be achieved by storing heat in the metal particles 24 having a thermal conductivity higher than that of air and having a heat capacity higher than that of the air, and releasing the stored heat amount in the vicinity of the freezing point that requires the most energy. Done.

  Moreover, since an appropriate gap can be formed by using a large number of metal particles, heat exchange between the air passing through the heat storage device 10 and the metal particles can be performed efficiently.

  In this way, the ice crystal band can be passed in a short time, so that deterioration or alteration of the object to be cooled can be prevented and high restoration property can be provided.

  Furthermore, since this invention has accommodated the above heat storage material 20 in the heat insulation case 12, the heat quantity stored by the heat storage material 20 can be reliably enclosed in the heat insulation case 12, and when needed. In addition, the amount of heat contained by the fan 18 can be released.

  Furthermore, since the heat storage material 20 itself is detachable from the heat insulating case 12, the heat storage material 20 can be taken out and washed, and the heat storage device 10 can be kept hygienic.

  Furthermore, since the location where the amount of heat is released can be concentrated by the opening 12a, the amount of released heat can be effectively supplied to the object to be cooled by directing the opening 12a toward the object to be cooled.

(Second Embodiment)
FIG. 7 is a diagram illustrating a second embodiment of the heat storage device 10 of the present invention. In the figure, the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this example, the heat storage device 10 is used for maintaining the temperature in the storage in the temperature holding device 80 such as a cold storage or a heat storage, not the cooling method of the object to be cooled.

  In the case of a cold storage, the temperature holding device 80 has substantially the same configuration as the cooling device 40 and includes a heat insulating wall body 82 and a door 84 formed on one side surface of the heat insulating wall body 82. The interior 86 is defined as a temperature control space that is insulated from the outside by the body 82 and the door 84 and whose temperature is to be adjusted to be constant.

A cooler 88 composed of an evaporator or the like that generates temperature-controlled air is installed in a part of the interior 86, and the heat storage device 10 is disposed in another part of the interior 86. In the chamber 86, a cooled object to be cooled can be stored as appropriate.
The refrigerant circulation circuit 60 passing through the cooler 88 is the same as the circulation circuit 60 of FIG.

  Further, any reference point of the heat storage device 10 (the temperature of the space 16 on the inlet side of the heat storage material 20, the temperature of the space 16 on the outlet side of the heat storage material 20 or the temperature of the heat storage material 20) A temperature sensor 92 is installed at an arbitrary reference point to constantly monitor the temperature at the reference point, and the signal is sent to the controllers 67 and 70.

  In the above embodiment, the operation when the temperature holding device 80 holds the temperature will be described.

  The signal from the temperature sensor 92 at the reference point in the chamber 86 is supplied to the controller 67 and compared with the set temperature signal, and it is determined whether or not the temperature difference is within the first allowable value range. Has been. Then, when the internal 86 temperature rises beyond the first allowable value upper limit, the compressor 66 starts to operate under the control of the controller 67 to cool down, and when the first allowable value lower limit is reached, the compressor 66 is stopped. To do. The compressor 66 repeats such intermittent operation.

  On the other hand, the signal from the temperature sensor 92 is also supplied to the controller 70 and compared with the set temperature signal, and it is determined whether or not the temperature difference is within the second allowable value range. The second tolerance range is smaller than the first tolerance range.

  When the internal chamber 86 temperature rises and exceeds the second upper limit (<first upper limit), the controller 70 sets the rotational speed of the fan 18 to a high speed. At this time, the compressor 66 has not yet started operation. By driving the fan 18, the amount of heat stored in the heat storage material 20 in the heat storage device 10 is released to the outside of the heat storage device 10 to compensate for temperature changes. The rotational speed of the fan 18 at this time can be adjusted as appropriate.

  When the heat radiation effect from the heat storage device 10 is weakened and the internal temperature 86 exceeds the first allowable value upper limit again, the operation of the compressor 66 is started by the control of the controller 67 and the internal space 86 is cooled by the cooler 88. At the same time, the rotational speed of the fan 18 is set to a low speed (including 0).

  Next, when the internal 86 temperature decreases and exceeds a second allowable value lower limit (> first allowable value lower limit), the controller 70 sets the rotational speed of the fan 18 to a high speed again, and the heat storage device. 10 heat storage starts. The cooling air from the cooler 88 exchanges heat with the heat storage material 20 having a higher thermal conductivity than air, and heat storage is quickly performed on the heat storage material 20.

  Then, when the inside 86 temperature decreases and reaches the first allowable value lower limit, the controller 67 stops the compressor 66. At this time, the controller 70 may also set the rotational speed of the fan 18 to a low speed (including 0), or when the temperature in the cabinet 86 further increases and then reaches the first allowable lower limit again. In addition, the rotational speed of the fan 18 may be set to a low speed (including 0).

  Even if an attempt is made to control to the set temperature only by the intermittent operation of the compressor 66 in the circulation circuit 60, overshoot (undershoot) always occurs and overcooling occurs. However, the heat storage device 10 stores the excessively cooled amount. In addition, when the internal temperature of the compressor 66 rises during the pause period, the low temperature heat stored in the heat storage device 10 is released, thereby extending the pause time of the intermittent operation of the compressor 66. Can reduce the cost.

  Alternatively, the compressor 66 is operated at midnight when the power is low, and the heat storage device 10 performs heat storage exclusively. During the day when the power is high, the fan 18 of the heat storage device 10 is driven weakly. Costs can be reduced by radiating heat little by little.

  In addition, the above example is a case where the set temperature to be temperature-controlled by the temperature holding device 80 is higher than the atmospheric temperature, and the case where a heater as an actuator that generates temperature-controlled air is provided in the temperature holding device 80 also stores heat. The apparatus 10 can be similarly applied by installing the apparatus 10 in the temperature holding apparatus 80.

(Modification 1 of heat storage device)
8-10 represents the modification of the thermal storage apparatus 10. FIG. The heat storage material 20 of the heat storage device 10 of this example includes a case 26 and a liquid 28 such as an antifreeze liquid filled in the case.

  The case 26 has a plurality of through holes 26a. The case 26 is preferably made of a metal having a high thermal conductivity, but is not limited thereto, and may be made of a synthetic resin. The case 26 may be formed with an inlet and a drain port (not shown).

  The antifreeze liquid can be injected into the case 26 through the inlet, and the antifreeze liquid can be discharged from the case 26 through the drain port. As the antifreeze, liquids such as methanol, ethanol, and salt water can be used. As shown in Table 1, antifreeze also has a higher conductivity than air, and can exhibit a heat storage effect in order to exhibit a higher heat capacity than air.

  In this example, air can flow from one opening 12a through the through hole 26a to the other opening 12a, and heat exchange between the antifreeze and air can be performed through the through hole 26a. ing.

  During normal times, heat is stored by the antifreeze and the case 26, and when the process near the freezing point or the internal temperature changes, the amount of stored heat is released to the outside, thereby effectively providing heat when a large amount of heat is required. it can.

  Also, if the antifreeze liquid is to be thawed at the freezing point of the object to be cooled, the latent heat (minus heat) released for the antifreeze liquid to thaw is used as the amount of heat necessary to pass the object to be cooled through the freezing point. Can do.

(Modification 2 of heat storage device)
FIG. 11 shows another modification of the heat storage device 10. The heat storage material 20 of the heat storage device 10 of this example includes a plurality of plates 30 of a high thermal conductivity body arranged in the space 16. The plurality of plates 30 are appropriately separated from each other, and an air flow can be generated from one opening 12a to the other opening 12a through the portion. Exchange is possible.

(Modification 3 of heat storage device)
FIG. 12 shows still another modified example of the heat storage device 10. The heat storage material 20 of the heat storage device 10 of this example has a plurality of fins 32 of a high thermal conductivity body aligned in a direction parallel to the direction from the one opening 12a to the other opening 12a. including. It is possible to generate an air flow from one opening 12a to the other opening 12a through a portion between adjacent fins 32, and heat exchange can be performed between the air and the fins 32. Yes.

(Modification 4 of heat storage device)
In the above-described example, air passes through the heat storage device 10 in the lateral direction (from right to left, from left to right, from front to back, and from back to front), but is not limited thereto. As shown in FIG. 13, air can be passed in the vertical direction (from top to bottom and from bottom to top) according to the shape of the heat storage material 20. Preferably, air is allowed to pass in the shortest direction in the heat storage material 20.

  Since the various heat storage devices 10 described above can be used by being installed in the cooling device 40 or the temperature holding device 80 such as an existing freezer, existing facilities can be used. The cooling device 40 does not control the flow rate and temperature of the refrigerant during the cooling of the object P, and the refrigerant is always in a constant amount or constant in the liquid phase process, the near freezing point process, and the solid phase liquid process. It may flow through the refrigerant circulation circuit 60 at a temperature. Since the heat storage device 10 can supply heat in the process near the freezing point where the most heat is required, it can pass through the freezing point in a short time, shorten the cooling time, and maintain the quality of the object to be cooled. It can be carried out.

  In the above-described embodiment, it is possible to configure a single component from a plurality of components, or to configure a single component from a plurality of components.

  When the object to be cooled is cooled according to the cooling device and the cooling method in which the heat storage device according to the first embodiment is installed (Example), the object to be cooled is cooled according to the cooling device and the cooling method according to Patent Document 1. A comparative experiment with the case (comparative example, FIG. 15) was conducted.

Conditions (same for both example and comparative example)
[Subject to be cooled]
・ Cherry (Sato Nishiki)
Average mass: 12 ± 1 g / piece Sugar content: 25.6 ° Bx
[Cooling system]
・ 1.5kW / -45 ℃
・ Internal volume: about 400L
・ Heat storage material: Aluminum alloy (metal grains in the examples, metal plates in the comparative examples)
・ Mass of heat storage material: 5kg

  From the preliminary measurement, it was found that the vicinity of the freezing point of the cherries was a region where the central temperature was -3.2 ° C to -2.8 ° C. Therefore, a point for switching from the liquid phase region process to the process near the freezing point in the embodiment (that is, a point for switching the operation of the fan 18), and a point for switching from the precooling process to the quick freezing process in the comparative example (that is, a point for opening the partition member). ) Was adjusted to the point where the center temperature of the cherry was -3 ° C.

[result]
FIG. 14 shows the time course of the surface temperature of the object to be cooled in the vicinity of the freezing point of the example and the comparative example. The ice crystal zone transit time in the vicinity of the freezing point of −3.2 ° C. to −3.8 ° C. was compared as follows.

  The example was able to pass through the freezing point at a rate approximately three times that of the comparative example. One reason for this large shortening is that, in the embodiment, the wind passing through the heat storage material 20 can pass through the heat storage material uniformly, and the heat stored in the heat storage material 20 can be reduced. It can be confined in a heat insulating case, and the heat storage effect is considered high. Further, as another reason, it is conceivable that low-temperature heat can be directly released from the heat storage device 10 toward the object to be cooled, as compared with the comparative example in which heat is stored in the cold storage chamber.

10 thermal storage device 12 heat insulation case 12a opening (inlet, outlet)
16 Space 18 Fan (Distribution Promotion Means)
20 Thermal storage material 22 Metal case 22a Porous wall surface (ventilation part)
24 Metal grain 40 Cooling device 66 Compressor 86 Inside (temperature control space)
P Object to be cooled

Claims (11)

A heat storage device installed in a cooling device that generates cooling air to cool an object to be cooled,
A heat insulating case that forms a space inside and has an inlet and an outlet;
A heat storage material capable of storing heat, including a high thermal conductivity body disposed in the space and having a higher thermal conductivity and heat capacity than air; and
A flow facilitating means disposed near the inflow port or the outflow port to promote the flow of cooling air from the inflow port toward the outflow port;
With
The heat storage material is capable of circulating the cooling air,
The flow promoting means suppresses the flow of cooling air from the inlet to the outlet from the start of cooling to the vicinity of the freezing point of the object to be cooled, and when it reaches the vicinity of the freezing point of the object to be cooled, it directs from the inlet to the outlet. A heat storage device that promotes circulation of cooling air.   The heat storage device according to claim 1, wherein the high thermal conductivity body has a large number of metal particles, and a gap through which air can flow is formed between the metal particles.   3. The heat storage material has a metal case for storing metal particles, and the metal case is provided with a ventilation portion that prevents the passage of the metal particles but allows the cooling air to flow therethrough. Cooling system.   The heat storage device according to any one of claims 1 to 3, wherein the heat storage material is detachable from a heat insulating case. A heat storage device installed in a cooling device that generates cooling air to cool an object to be cooled, wherein the heat storage device forms a space inside and has an inflow port and an outflow port; And a heat storage material capable of storing heat, including a high thermal conductivity body having a higher thermal conductivity and heat capacity than air, and disposed in the vicinity of the inflow port or the outflow port, and directed from the inflow port to the outflow port. A cooling method for cooling an object to be cooled in the cooling device using a heat storage device including a flow promoting means for promoting the flow of cooling air,
From the start of cooling of the object to be cooled to the vicinity of the freezing point, a first cooling step for suppressing the flow of cooling air from the inflow port through the heat storage material toward the outflow port by the flow promoting means,
A second cooling step for accelerating the flow of cooling air from the inlet through the heat storage material toward the outlet when the vicinity of the freezing point of the object to be cooled is reached;
A cooling method comprising:   Prior to the first cooling step, the flow of cooling air is directed from the inlet to the outlet through the heat inlet by the flow promoting means, and the temperature of the heat storage is reduced below the freezing point of the object to be cooled. The cooling method according to claim 5, further comprising a precooling step of cooling.   The cooling method according to claim 5, further comprising a step of feeding the object to be cooled into the cooling device, the step of directing the outlet to the object to be cooled.   After the second cooling step, when the temperature inside the heat storage device becomes the same as the temperature outside the heat storage device, the cooling air flows through the heat storage material from the inflow port to the outflow port by the flow promoting means. The cooling method according to any one of claims 5 to 7, further comprising a third cooling step to be suppressed.   A step of promoting the circulation of cooling air from the inflow port through the heat storage material toward the outflow port when the temperature outside the heat storage device reaches a predetermined temperature lower than the freezing point of the object to be cooled. The cooling method according to claim 5, further comprising: A heat storage device arranged in a temperature control space that is adjusted to a set temperature by intermittent operation of an actuator,
A heat insulating case that forms a space inside and has an inlet and an outlet;
A heat storage material capable of storing heat, including a high thermal conductivity body disposed in the space and having a higher thermal conductivity and heat capacity than air; and
A flow facilitating means disposed near the inflow port or the outflow port to promote the flow of temperature-controlled air from the inflow port toward the outflow port;
With
The heat storage material is capable of circulating the temperature-controlled air,
The flow promoting means suppresses the flow of temperature-controlled air from the inlet to the outlet when the temperature of the temperature-controlled space becomes the first allowable limit temperature and the actuator starts to operate. When the temperature of the first temperature reaches the second allowable limit temperature before reaching the first allowable limit temperature, the circulation of the temperature-controlled air from the inlet to the outlet is promoted. A heat storage device installed in a cooling device that generates cooling air to cool an object to be cooled,
A heat insulating case that forms a space inside and has an inlet and an outlet;
A heat storage material capable of storing heat, including a high thermal conductivity body disposed in the space and having a higher thermal conductivity and heat capacity than air; and
A flow facilitating means disposed near the inflow port or the outflow port to promote the flow of cooling air from the inflow port toward the outflow port;
The heat storage material is a heat storage device in which the cooling air can flow.

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