JP2008082580A - Freezer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator capable of jetting large flow of cold air in a normal operation and a defrosting operation. <P>SOLUTION: This freezer comprises a heat pump 10 capable of reaching -30°C or lower, a cooler 11 disposed in a heat absorbing portion of the heat pump 10, a first cold storage member 20 having a melting point in a temperature range of lower than -30°C to which the heat pump can reach, a first storage compartment 38 for storing a first cooled object, a circulation passage for circulating the cold air, bypass means 51-53 for separating the first cold storage member 20 and the first storage compartment 38 from the cooler 11, a defrosting means performing defrosting when the circulation passage is separated, and a circulation fan 58 for circulating the cold air. By applying the cold storage member having a melting point near a target cooling temperature, a large amount of cold air of approximately constant temperature can be supplied for a long time by utilizing heat of melting. Accordingly, the inside of the first storage compartment can be kept at a very low temperature even during the defrosting operation while stopping the heat pump 10. The temperature stability in the normal operation can be also improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a freezer capable of realizing high performance for quick freezing, deep temperature storage, constant temperature maintenance, and the like.

  In order to store foods frozen in high quality, quick freezing, deep temperature storage, and constant temperature maintenance are required.

  As a conventional freezer, when food is rapidly frozen, the air is blown into the freezer compartment through a cold storage member provided with a through hole to disturb the heat transfer boundary film (temperature boundary layer) on the food surface. An apparatus for improving the freezing rate by reducing the heat transfer resistance between the air and the cold is disclosed (Patent Document 1, FIG. 1, etc.).

In order to rapidly freeze food, it is necessary to reduce the heat transfer resistance between the food and cold air on the food surface. At the same time, it is effective to lower the temperature of the cold air applied to the food to increase the temperature difference between the freezing progress point inside the food and the food surface and the temperature difference between the food surface and the cold air. . As a result, heat conduction from the inside of the food to the food surface and heat transfer from the food surface to the cold air can be promoted, and quick freezing can be realized.
Japanese Patent Laid-Open No. 2004-77088

  However, in the freezer of Patent Document 1, the temperature in the freezer compartment is set to about −20 ° C., and at that temperature, the thickness inside the food is about 30 to 50 mm thick. The temperature gradient in the vertical direction becomes small, heat transfer is not performed sufficiently, and it takes time to freeze around the food center, making rapid freezing difficult.

  Moreover, in the freezer of patent document 1, although the aluminum block is used as a cool storage member, the specific heat of aluminum in the vicinity of −20 ° C. is about 0.9 J / g · ° C., and sufficient heat absorption is possible. I couldn't say that.

  For example, the amount of heat that can be absorbed while a 1 kg −20 ° C. aluminum block rises to −16 ° C. is 0.9 J / g · ° C. × 1 kg × 4 ° C. = 3.6 kJ. On the other hand, when beef is taken as an example of fast-frozen food, its freezing latent heat is 188 J / g. To freeze two pieces of 150 g of beef steak, a total of 300 g, only the freezing latent heat is 188 J / g × 300 g = The heat of 56.4 kJ must be removed. In order to absorb 28.2 kJ, half of the freezing latent heat, by increasing the temperature from -20 ° C to -16 ° C with an aluminum block, as much as 7.8kg of aluminum is required. Cost increases.

  On the other hand, if the amount of aluminum is reduced, in order to absorb the latent heat of freezing in a short time, a heat pump device having a large cooling capacity is required, which makes the device large and heavy, and increases the component cost.

  By the way, the cooling of the cold air is performed by circulating and contacting the cold air to the cooler installed in the heat absorption part of the heat pump, so the moisture in the cold air gradually adheres to the cooler surface as ice and the cooling capacity Decreases. Therefore, a defrosting operation is periodically performed in which the temperature of the cooler is raised to melt and remove the attached ice.

  However, if defrosting operation is performed, cooling during that time cannot be performed, so that it is difficult to realize deep temperature storage and constant temperature maintenance.

  This invention makes it the subject which should be solved to provide the freezer which can eject cold air with low temperature continuously with a large flow rate not only at the time of normal operation but also at the time of defrosting operation.

  The freezer of the present invention that solves the above problems is a heat pump that can reach −30 ° C. or less, a cooler installed in the heat absorption part of the heat pump, and within a temperature range that can be reached by the heat pump at −30 ° C. or less. A first storage member having a melting point, a first storage chamber having a space for storing the first object to be cooled, the cooler, the first cool storage member, the first storage chamber, and the cooler. In this order, a circulation path for circulating the cool air, and between the downstream side of the cooler and the upstream side of the first cool storage member, the downstream side of the first storage chamber and the upstream side of the cooler in the circulation path. By connecting the first cool storage member and the first storage chamber, the bypass means for separating the cooler, and when the circulation path is separated by the bypass means, Defrost by adjusting the temperature Characterized in that it has means to take, and a circulation fan for circulating the cold air in the circulation path.

  By adopting a cold storage member having a melting point near the intended cooling temperature, it is possible to supply a large amount of cold air at a substantially constant temperature for a long time using the heat of fusion. That is, until the cool storage member is melted, it is possible to supply cold air of the same temperature to the first storage chamber, and it is possible to keep the first storage chamber at a very low temperature even during the defrosting operation in which the heat pump is stopped. It becomes possible. Further, since the cold air that has passed through the first cold storage member is introduced into the first storage chamber, the temperature stability can be increased even during normal operation.

  A second storage chamber having a space for storing the second object to be cooled, and a temperature higher than the first cold storage member disposed in the second storage chamber or a position upstream of the second storage chamber; A second regenerator member having a melting point, wherein the second storage chamber and the second regenerator member are connected to the circulation path in parallel with the first storage chamber. it can. In particular, it is desirable that the second storage chamber and the second cold storage member be connected to the circulation path at a position parallel to the first cold storage member and the first storage chamber. In this case, the circulation path has circulation path switching means for switching the flow of the cold air between the first storage chamber and the second storage chamber, and the heat pump includes the first storage chamber and the second storage chamber. The operation is switched so that the temperature reached by the cooler becomes appropriate with the switching of the flow of the cool air by the circulation path switching means between the storage chambers.

  Furthermore, the second storage chamber having a space for storing the second object to be cooled, and the second storage chamber or a position upstream of the second storage chamber and higher temperature than the first cold storage member. A second cold storage member having a melting point, and the second storage chamber and the second cold storage member are connected to the circulation path at a position downstream of the first storage chamber. You can also.

  That is, the refrigeration performance in each storage chamber can be improved by selecting each of the cold storage members having a melting point corresponding to a different temperature for each required number of storage chambers. Even if there are four or more types of storage chambers, they can be provided for each required temperature.

  For example, a third storage chamber having a space for storing a third object to be cooled, and a temperature higher than the second cold storage member disposed in the third storage chamber or at a position upstream of the third storage chamber. A third regenerator member having a melting point, and the third storage chamber and the third regenerator member are connected to the circulation path at a position parallel to or downstream of the second storage chamber. Can be adopted.

  Here, as the first cold storage member and / or the second cold storage member, a material having a melting point near the desired freezing temperature and having as much heat of fusion as possible is appropriately selected. For example, the first regenerator member is any one of a mixture of ethylene glycol and water, a mixture of propylene glycol and water, a mixture of ethanol and water, a mixture of potassium carbonate and water, and a mixture of calcium chloride and water. It is desirable to be. The third cold storage member can be selected from ethylene glycol and a mixture of sodium chloride and water.

  In addition, the first cold storage member, the second cold storage member and / or the third cold storage member includes an outer box and heat transfer fins that are in contact with the outer box and disposed in the outer box. It is desirable to be housed in the cold storage member housing case. Heat can be effectively transferred to the cold storage member, and melting and solidification can proceed evenly.

  The freezer of the present invention can supply a large amount of cold air by selecting an appropriate cold storage member, and can realize quick freezing at a lower cost than the prior art. In addition, since the cold storage member has a melting point, it is possible to reduce the temperature fluctuation of the supplied cold air, and even if the cooler is not expected to function sufficiently during defrosting operation, the temperature inside the storage room is high. Can be maintained.

  The freezer of this embodiment can be operated with a heat pump having a relatively small capacity relative to the required quick freezing capacity as compared with a conventional freezer. In addition, when a heat pump having the same or larger capacity as that of a conventional freezer is employed, a higher rapid freezing capacity can be exhibited.

(Constitution)
The freezer of this embodiment has a heat pump, a cooler, a first cool storage member, a first storage chamber, a circulation path, a bypass means, a defrosting means, a circulation fan, and other necessary means.

  The heat pump has the ability to reach the temperature of the cooler below -30 ° C. Although the structure is not particularly limited, a pulse tube refrigerator or a Stirling refrigerator having a relatively small size and a low ultimate temperature is desirable.

  The first cold storage member is a member having a melting point within a temperature range of −30 ° C. or lower and reachable by the heat pump. The first cold storage member may be a pure substance or a mixture. A large amount of heat can be absorbed when the first cold storage member melts.

  That is, the first cold storage member can absorb a large amount of heat in the vicinity of the melting point. Therefore, it is desirable to set the melting point of the first cold storage member in the vicinity of the operating temperature at which it is desired to reach and maintain. For example, in the case of a freezer used at about −30 ° C., the temperature to be used is set to be around −30 ° C., and in the case of a freezer used near −40 ° C. It is desirable to set the temperature around 50 ° C, -60 ° C, and -70 ° C. It is more desirable to set the melting point to a temperature several degrees lower than the use temperature.

  In addition, when adopting a mixture as the first cold storage member, the melting point may have a width, but it is sufficient if the range of the melting point where the width is generated overlaps the range required for the first cold storage member. Furthermore, it is desirable that the range of the melting point is included in the range required for the first cold storage member.

  It is desirable to employ a material having a large heat of fusion as the first cold storage member. Specifically, a mixture of propylene glycol, ethylene glycol and water, a mixture of propylene glycol and water, a mixture of ethanol and water, a mixture of potassium carbonate and water, and a mixture of calcium chloride and water, a mixture of formic acid and water, Any of a mixture of acetic acid and water can be exemplified, and any mixture thereof can be exemplified.

  For example, the melting point of an aqueous solution containing 70% by mass of ethylene glycol is −65 ° C., the melting point of an aqueous solution containing 60% by mass of propylene glycol is −48 ° C., the melting point of an aqueous solution containing 70% by mass of ethanol is −55 ° C., The melting point of an aqueous solution containing 40% by mass of potassium is −37 ° C., and the melting point of an aqueous solution containing 30% by mass of calcium chloride is −55 ° C. And it is possible to change melting | fusing point to desired temperature vicinity by changing these mixing ratios.

  The first cold storage member can be stored and used in some kind of container (cool storage member storage case). When the first cold storage member is housed in a container, heat exchange is performed through the wall of the container. Therefore, it is desirable that the material constituting the container is made of a material (metal such as aluminum or copper) having excellent thermal conductivity. Moreover, in order to advance heat exchange efficiently, a heat-transfer fin can be formed in the wall of a container and a surface area can be increased. By forming heat transfer fins on the outside of the container, heat exchange can be efficiently performed with the gas (cold air) flowing outside the container, and heat transfer fins are formed on the inside of the container. Thus, efficient heat transfer in the first cold storage member can be performed.

  The first storage chamber has a space for storing an object to be cooled. The wall of the first storage chamber is preferably formed of a heat insulating material. Moreover, you may arrange | position the 1st cool storage member mentioned above to the wall surface. It is desirable to form an outlet through which cool air can be blown out on the upper, lower, left and right walls of the first storage chamber. In particular, it is desirable to form a large number of jet outlets on both the bottom surface and the top surface so that cool air can be jetted from the vertical direction of the object to be cooled. A door can be provided in the first storage chamber in order to facilitate taking in and out of the object to be cooled in and out of the internal space.

  The circulation path is a flow path for circulating cold air in the order of the cooler, the first cold storage member, the first storage chamber, and the cooler. The flow of cool air in the circulation path is formed by a circulation fan. The circulation fan is a fan that circulates cold air in the circulation path. Regardless of the state of the circulation path (regardless of whether the circulation fan is separated by a bypass means described later), the circulation fan preferably has a mode in which cool air flows from the first cold storage member toward the first storage chamber in the circulation path. . For example, it can arrange | position between a cooler and a 1st cool storage member.

  The cold air cooled by the cooler cools the first cold storage member. The cold air that has cooled the first cold storage member flows into the first storage chamber, and cools the space inside the first storage chamber and the object to be cooled disposed in the space. The cool air whose temperature has risen is returned to the cooler again.

  A bypass means is provided in the circulation path. The bypass means is means for separating the circulation path into two or more by a bypass path that bypasses a part of the circulation path for the purpose of performing the defrosting operation. The circulation path separated by passing through the bypass means forms one flow path again by closing the bypass means.

  Specifically, the bypass means connects the first cool storage unit between the downstream side of the cooler and the upstream side of the first cool storage member and the downstream side of the first storage chamber and the upstream side of the cooler. It is a means to isolate | separate a member and a 1st storage chamber, and a cooler. As the bypass means, a combination of a bypass flow path and a damper that is operated by an electromagnetic force and switches the flow path can be adopted.

  The defrosting means is a means for adjusting the temperature of the cooler and defrosting when the circulation path is separated by the bypass means. Specifically, heating with a heater or the like, stopping the operation of the heat pump, introducing hot air or outside air, alone or in combination, etc., raised the temperature of the cooler to 0 ° C. or higher and adhered to the cooler. It melts and removes ice.

  As other means, a combination of the second storage chamber and the second cold storage member and a combination of the third storage chamber and the third cold storage member can be adopted. The second cold storage member and the third cold storage member are members having the same melting point as that of the first cold storage member except that the second cold storage member and the third cold storage member are members having melting points selected according to the operating temperatures in the second storage chamber and the third storage chamber, respectively. Can be selected. The second storage chamber is used at a higher temperature than the first storage chamber, and the third storage chamber is used at a higher temperature than the second storage chamber.

  Specifically, when the second storage chamber is used at about −30 ° C., a substance having a melting point at a temperature of −30 ° C. or lower is adopted as the second cold storage member, and the second storage chamber is about −20 ° C. Is used, the melting point is set in the vicinity of the working temperature such that a substance having a melting point at a temperature of −20 ° C. or lower is adopted for the second cold storage member.

  Here, the object to be cooled is stored by selecting the first to third storage chambers according to the required freezing temperature, freezing speed, and the like. For example, an object to be cooled that requires long-term storage and needs to be quickly frozen is stored as a first object to be cooled in a first storage chamber capable of rapid freezing. Similarly, the other storage chambers are selected according to the refrigeration conditions required for the object to be cooled.

  Here, the “first to third objects to be cooled” used in this specification are distinguished from the first to third storage chambers that are chambers for storing the objects to be cooled. It does not change with the type or number of objects. For example, even if the first object to be cooled stored in the first storage chamber is transferred to the second storage chamber, it is called the second object to be cooled. Even an object to be cooled can be stored.

  As a material desirable as the second cold storage member, the same material as the first cold storage member can be adopted. A desirable material for the third cold storage member is any one of ethylene glycol, propylene glycol, and a mixture of sodium chloride and water. For example, the melting point of ethylene glycol is −13 ° C., the melting point of propylene glycol is −28 ° C., and the melting point of a 23 mass% aqueous solution of sodium chloride is −21 ° C.

  The second storage chamber can be provided on the downstream side of the first storage chamber, and can also be provided in parallel with the first storage chamber. The third storage chamber can be provided on the downstream side of the first storage chamber and / or the third storage chamber, and can also be provided in parallel with the first storage chamber and / or the second storage chamber.

  In the case where the second storage chamber (third storage chamber) is provided in parallel to the first storage chamber (first storage chamber and / or second storage chamber), the following configuration may be employed. First, the circulation path can have circulation path switching means for switching the flow of cold air between the first storage chamber and the second storage chamber. And it is desirable for the circulation path switching means to switch the operation of the heat pump so that the temperature reached by the cooler becomes appropriate with the switching of the flow of cold air between the first storage chamber and the second storage chamber. . Since the efficiency of the heat pump varies depending on the temperature reached by the cooler, high efficiency can be realized by controlling the heat pump so that the temperature becomes an appropriate temperature.

(Function and effect)
Since the freezer of this embodiment has the above composition, it demonstrates the following operation effects.

  The heat pump is operated and the temperature of the cooler is cooled to a target temperature not higher than −30 ° C. Since the circulation fan generates the circulating flow toward the cooler, the first cool storage member, the first storage chamber, and the cooler, the cool air cooled by the cooler is the first cool storage member. Then, it reaches the first storage chamber and cools. The first cold storage member is solidified by being cooled below the freezing point. After the solidification is completed, the first cold storage member stores cold, so that the temperature fluctuation in the first storage chamber can be reduced.

  More specifically, when the temperature rises by putting an object to be cooled in the first storage chamber, the cooler alone may not be sufficient to cool the cold air whose temperature has risen again to the target temperature. is there. In that case, the temperature fluctuation can be reduced by assisting cooling by the first cold storage member.

  Since the first cold storage member is solidified, it stays at the melting point until the whole is completely melted, and the temperature of the cold air can be maintained at a temperature near the melting point. In general, since the heat of fusion of a substance is greater than the specific heat of the substance, a large amount of heat can be absorbed before the first cold storage member is completely melted.

  Therefore, it becomes possible to inject a large amount of cool air having a low temperature onto the object to be cooled, which can contribute to the realization of quick freezing and constant temperature holding.

  Moreover, a required freezing temperature can be efficiently realized by adopting a second cold storage member having a melting point near the required freezing temperature and further providing a second storage chamber. That is, it is possible to keep the temperature of the cold air at a temperature near the melting point when the second cold storage member melts.

  Similarly, by adopting a third cold storage member having a selected melting point temperature and providing a third storage chamber, the cooling capacity in the vicinity of the melting point of the third cold storage member can be improved. Hereinafter, if necessary, the fourth and fifth cold storage members may be employed.

  And according to use of a freezer, the water | moisture content in atmosphere adheres to a cooler and it becomes ice. If ice adheres, heat transfer resistance will occur, so if ice adheres to some extent, it is necessary to defrost. Since defrosting requires the temperature of the cooler to be 0 ° C. or higher, cooling with a heat pump cannot be performed during defrosting. In the freezer of this embodiment, it becomes possible to isolate | separate the cooler of a circulation path by a bypass means, and only a cooler can be heated up to 0 degreeC or more. During defrosting, the temperature of the first storage chamber can be maintained by the first cool storage member (and the second cool storage member and the third cool storage member, if present), so the temperature change in the first storage chamber is minimized. Defrosting can be performed.

  When the second storage chamber (third storage chamber) is provided in parallel to the first storage chamber (first storage chamber and / or second storage chamber) and the circulation path is switched by the circulation path switching means In the first storage chamber and the second storage chamber (third storage chamber), the heat pump can be appropriately operated at different use temperatures. That is, by sequentially switching the circulation path between the first cold storage member and the first storage chamber, the second cold storage member and the second storage chamber, and the third cold storage member and the third storage chamber, for each temperature. It becomes possible to select an operating condition in which efficiency is high.

  In addition, since the first to third cool storage members can absorb a large amount of heat, the first to third cool storage members are solidified by using midnight power with a low power charge, etc., and stored in a time zone where the power charge is high. By performing heat absorption by the first to third cold storage members, it is possible to contribute to the suppression of electricity costs and the leveling of power usage.

  Hereinafter, the freezer of this invention is demonstrated in detail based on an Example.

(Example 1: Configuration)
As shown in FIGS. 1 and 2, the freezer of this embodiment includes a heat pump 10, a cooler 11, a first cool storage member 20, a first storage chamber, a circulation path 42, a bypass means, a defrosting means (not shown), and a circulation use. A fan 58 and a control circuit (not shown) are housed in a housing.

  The housing is provided so as to be openable and closable at a housing main body having a box-shaped inner container 61 whose front surface is open and a box-shaped outer box 62 whose front surface is open to store the container. And a door 63. Between the inner container 61 and the outer box 62, a heat insulating material such as a foamed polyurethane 64 and a vacuum heat insulating material 65 is filled. The door 63 is filled with a heat insulating material as in the case body. A space between the door and the housing main body is kept airtight by a packing 66 attached around the inner surface of the door.

  The housing defines the first storage chamber together with the first cold storage member 20. That is, the inside of the housing defined by the inner container 61 and the door 63 is partitioned by the cool storage container 21 in which the first cool storage member 20 is enclosed, and the front portion of the partitioned forms the first storage chamber. . The 1st cool storage member 20 is protrudingly provided from the ceiling part from the center inside a housing | casing and a little back.

  A cooler 11 and a circulation fan 58 installed in the heat absorption part of the heat pump 10 are arranged in the rear part inside the housing. The circulation fan 58 sends cool air toward the first cold storage member 20 from the rear inside the housing. The type of the circulation fan 58 is not particularly limited, and a propeller fan, a sirocco fan, a turbo fan, or the like is used.

  A circulation path partitioned by a partition plate 43 is formed in the rear part inside the housing. The circulation path is formed so that the cool air can circulate in the order of the cooler 11, the circulation fan 58, the first cool storage member 20, the front portion inside the housing, and the cooler 11. And the bypass flow path 53 as a bypass means which bypasses the part of the cooler 11 in a circulation path is formed, and it is formed in the damper 52 and bypass flow path 53 which were formed in the flow path by the side which flows through the cooler 11. The flow of the circulation path can be switched by alternately opening and closing the dampers 51. By opening the damper 52 and closing the damper 51, the cold air passes through the cooler 11, and by opening the damper 51 and closing the damper 52, the cold air flows without passing through the cooler 11. Defrosting is performed in a state where the cold air flows without passing through the cooler 11. The defrosting means is a heater for heating the cooler 11 to 0 ° C. or higher. The defrosting means is operated in a state where the damper 51 is opened and the damper 52 is closed and the cold air flows without passing through the cooler 11.

  The first cold storage member 20 is enclosed in a rectangular parallelepiped cold storage container 21 (cold storage member storage case: outer box) so that the specific surface area is large. The cold storage container 21 is arranged with the surface having a large thickness facing the front-rear direction inside the housing, and the partition plate 43 is arranged so as to form a circulation path 42 so that cold air flows along the surface of the cold storage container 21. ing.

  Heat transfer fins 22 are provided inside the cold storage container 21 for the purpose of promptly and uniformly exchanging heat with the first cold storage member 20 (FIG. 3). Here, for the purpose of efficiently exchanging heat with cold air, the cold storage container 21 may be provided with heat transfer fins 23 protruding outside the container as shown in FIGS. Furthermore, it is also possible to provide heat transfer fins 24 projecting inward as shown in FIG.

  As the 1st cool storage member 20, the mixed substance of 70 mass% of ethylene glycol and 30 mass% of water can be illustrated. This mixed material has an eutectic point at −65 ° C. and a heat of fusion of about 70 J / g. Considering the case of freezing two pieces of 150g beef steak chilled at a temperature of 5 ° C and a total of 300g as the object to be cooled, the freezing point of beef is about -2 ° C, the specific heat above the freezing point of beef Is 3.08 J / g · ° C., and the latent heat of freezing is 188 J / g. The amount of heat that must be removed to cool 300 g of beef from 5 ° C. to −2 ° C. is 3.08 J / g · ° C. × 300 g × 7 ° C. = 6.5 kJ, and 300 g of beef must be removed to freeze it. The amount of heat that must be obtained is 188 J / g × 300 g = 56.4 kJ, and a total of 62.9 kJ must be removed. This amount of heat can be absorbed by melting about 900 g of a mixed material of 70% by mass of ethylene glycol and 30% by mass of water.

  Practically, the amount of the first cold storage member 20 is set to about 2 kg with an allowance of about twice this. As the size of the cold storage container 21 at this mass, since the density of the mixed material of 70% by mass of ethylene glycol and 30% by mass of water is about 1.1 g / mL, for example, 300 mm in length, 300 mm in width, thickness It becomes compact about 20mm.

  The heat pump 10 is a Stirling refrigerator or a pulse tube refrigerator, and a heat absorption part in which a low-temperature heat exchanger is housed is inserted into a circulation path via a heat insulating material of a housing. A cooler 11 is installed in the heat absorption part of the heat pump 10, and a radiator 12 is installed in the heat dissipation part of the heat pump 10. The cooler 11 and the radiator 12 are formed of a material having high thermal conductivity such as an aluminum material and a copper material, and are members that have a large number of fins and allow air to flow through the gaps between the fins.

  Stirling refrigerators have a working fluid, for example helium, sealed in a pressure vessel at 3.0 MPa, and a cylindrical power piston made of resin material can reciprocate behind the cylinder located in the center of the pressure vessel. A displacer made of a resin material is installed in front of the power piston so as to reciprocate.

  A compression space between the upper surface of the power piston and the lower surface of the displacer is communicated with an expansion space on the upper surface of the displacer through an opening on the side surface of the cylinder, a room temperature heat exchanger, a regenerator, and a low temperature heat exchanger.

  A cooler 11 is installed around the heat absorption unit containing the low-temperature heat exchanger, and a radiator 12 is installed around the heat dissipation unit containing the room temperature heat exchanger. The power piston is supported via a rod by a leaf spring fixed to the pressure vessel and connected to a cylindrical member around which a coil is wound. The coil is placed in a magnetic field in a gap formed by a magnet and a yoke. When an alternating current is passed through the coil, the coil is reciprocated in the front-rear direction, and the connected power piston is reciprocated.

  The displacer is supported by a leaf spring fixed to the pressure vessel via a rod penetrating the center of the power piston, and reciprocates due to pressure fluctuations of the working fluid caused by the reciprocation of the power piston. The natural frequency of the displacer is set larger than the natural frequency of the power piston, and the displacer reciprocates with a phase advance of about 90 degrees from the power piston.

  By the movement of the power piston and the displacer, the working fluid that has been compressed in the compression space and raised in temperature dissipates heat to the room temperature heat exchanger, and is sent to the expansion space while being cooled by the regenerator, where it is expanded to lower the temperature, Heat is absorbed from the low-temperature heat exchanger and returned to the compression space while cooling the regenerator.

  By repeating this, the pumping of heat from the heat absorption part to the heat radiation part (heat pump) is continuously performed, and the cooler 11 installed in the heat absorption part in the freezer is cooled. The heat pumped up by the heat radiating part is transmitted to the air taken in from the air suction port at the lower rear surface of the housing by the heat radiating fan 14 via the radiator 12 installed in the heat radiating part. Is discharged from the air discharge port at the upper rear surface of the housing.

  The pulse tube refrigerator shortens the Stirling refrigerator's displacer to the room temperature side to form a room temperature displacer, and controls the displacement of the working fluid in the expansion space via the working fluid in the pulse tube. The room temperature displacer is a power piston. On the other hand, it is reciprocated with a phase advance of about 60 to 80 degrees.

  By the movement of the power piston and the room temperature displacer, the working fluid that has been compressed in the compression space and raised in temperature dissipates heat to the room temperature heat exchanger and is sent to the expansion space while being cooled by the regenerator, where it is expanded and the temperature drops. The heat is absorbed from the low-temperature heat exchanger and returned to the compression space while cooling the regenerator. By repeating this, the pumping of heat from the heat absorption part to the heat radiation part (heat pump) is continuously performed, and the cooler 11 installed in the heat absorption part in the freezer is cooled. A rectifier is installed at the low temperature end of the pulse tube so as not to disturb the uniform gas reciprocating flow in the pulse tube. In the pulse tube refrigerator, since the displacement of the working fluid in the expansion space is controlled via the working fluid in the pulse tube, heat transfer from the compression space at room temperature to the low temperature expansion space by the displacer present in the Stirling refrigerator. There is no heat transfer and heat penetration into the freezer can be kept small.

  The interior of the first storage chamber is partitioned into a plurality of spaces by partition plates 31, 32 and 33. Appropriate cooling performance is achieved by controlling the flow of cool air in each space. In the freezer of this embodiment, the first storage chamber is partitioned into a quick freezing chamber 37 and a deep cold storage chamber 38. The quick freezing chamber 37 is partitioned by partition plates 31 and 32 through which cool air can circulate, and a large amount of cool air is flowed through an object to be cooled that requires quick freezing. The cold air flowing into the quick freezing chamber 37 flows into the deep cold storage chamber 38 as it is, but a damper 35 and a damper 36 are provided to suppress temperature changes in the deep cold storage chamber 38.

  The damper 35 is formed at the entrance to the flow path 44 that bypasses from the quick freezing chamber 37 to the deep cold storage chamber 38. The damper 36 is formed at the entrance to the flow path 45 extending from the deep cold storage chamber 38 to the cooler 11.

  Normally, the damper 35 is closed so as to form a flow from the quick freezing chamber 37 to the cryogenic storage chamber 38 to stop the flow of cold air from the quick freezing chamber 37 to the flow path 44, and the damper 36 is opened to open the quick freezing chamber. The cool air is allowed to flow from 37 to the deep cold storage chamber 38.

  In the case of performing quick freezing, the damper 35 is opened and the damper 36 is closed, so that the cold air flowing into the quick freezing chamber 37 does not flow into the deep cold storage chamber 38 but passes through the flow path 44 returning to the cooler 11 as it is. To do. As a result, the cold air heated in the quick freezing chamber 37 does not flow into the deep cold storage chamber 38, and quick freezing and constant temperature holding of the deep cold storage chamber 38 can be achieved when freezing a high-temperature object to be cooled.

  A temperature sensor (not shown) is provided to grasp the state of the freezer. The temperature sensor is disposed in the quick freezing chamber 37, the deep cold storage chamber 38, and the first cold storage member 20. The output from the temperature sensor is input to the control circuit.

  It has an indicator for notifying the operation status of the freezer to the outside and an operation panel (not shown) for operating the operation status from the outside. The operation panel is connected to a control circuit to control input from the operation panel and output to the operation panel.

(Function / Effect: Normal operation)
By closing the damper 51 and opening the damper 52, a circulation path through which cool air flows through the cooler 11 is formed. By operating the circulation fan 58, the cold air circulates in the circulation path. The cooler 11 is cooled by operating the heat pump 10. The cool air is cooled by touching the cooler 11 with the cool air. The cooled cold air reaches the cold storage container 21. The first cold storage member 20 is cooled and solidified through the outer wall of the cold storage container 21 and the cooling fins 23. Whether or not the first regenerator member 20 has solidified is determined to be that the solidification has been completed when the temperature of the first regenerator member 20 is lower than the melting point by a predetermined temperature (for example, about 5 ° C.). In normal operation, the heat pump 10 is operated at a high output until the first cold storage member 20 is solidified.

  -Quick freezing: When an object to be cooled is put in the quick freezing chamber 37 and the quick freezing operation is selected by the operation panel (not shown), the control unit opens the damper 35 and closes the damper 36. The rotation speed of the circulation fan 58 is increased to increase the amount of cool air circulating in the circulation path.

  The cool air flows in the order of the cooler 11, the circulation fan 58, the cold storage container 21, the quick freezing chamber 37, and the cooler 11. Since the flow of cold air increases, the cooling capacity from the cooler 11 may not be sufficient. Even in such a case, the cold air that has not been sufficiently cooled by the cooler 11 can be absorbed by the first cold storage member 20 by contacting the outer wall of the cold storage container 21 to be sufficiently cold. Since the temperature of the first cold storage member 20 does not rise until the whole is completely melted, low-temperature cold air can be supplied for a long time.

  When the temperature sensor arranged in the quick freezing chamber 37 detects that the temperature in the quick freezing chamber 37 has sufficiently decreased, or there is a temperature difference between the cold air flowing into the quick freezing chamber 37 and the cold air flowing out. When the temperature falls below the predetermined value, it is determined that the rapid freezing of the object to be cooled in the quick freezing chamber 37 is finished, and the quick freezing operation is stopped and the operation is shifted to the constant temperature holding operation. In addition, when the temperature of the deep cold storage chamber 38 is high or high even during the quick freezing operation, an operation similar to the constant temperature holding operation described later is performed and the temperature of the deep cold storage chamber 38 does not exceed a predetermined value. Can be controlled.

  The actual temperature in the freezer can be exemplified as follows. Cold air with a large flow rate of −60 ° C. is ejected into the quick freezing chamber 37 to take heat away from the object to be cooled. For example, the cool air whose temperature has risen to −40 ° C. is returned from the open damper 35 (suction port) to the cooler 11 through the suction duct 44.

  Since the cost of the heat pump 10 adopted is low enough to maintain the constant temperature holding operation described later, a large amount of cold air that has risen to −40 ° C. can be obtained only with the cooler 11 − In some cases, the temperature can only drop to about 45 ° C. In that case, the cold air circulated by the circulation fan 58 reaches the outer wall of the cold storage container 21 without being sufficiently cooled.

  The large amount of cold air that has not been sufficiently cooled is cooled to about −60 ° C. by the first cold storage member 20 that melts at −65 ° C. while flowing on the surface of the cold storage container 21 having a large area, Is erupted. When the solidified first cold storage member 20 is melted and changed to a liquid, the first cold storage member 20 absorbs heat at a constant temperature until it is changed to a liquid. Therefore, even if the cooling capacity of the heat pump 10 is small, it becomes possible to continuously blow out cold air of −60 ° C. to the object to be cooled at a large flow rate, and the temperature between the surface of the object to be cooled and the internal freezing point. The difference can be increased. As a result, heat transfer from the inside of the object to be cooled to the surface is promoted, and quick freezing becomes possible regardless of the shape and thickness of the object to be cooled.

  FIG. 7 shows a blank flat plate freezing model (edited by the Japan Society of Refrigeration and Air Conditioning, “Food Freezing Technology for Food Related Persons” (2000). The calculation result under a certain realistic condition using “year issue” (see page 37) is schematically shown.

  (A) in FIG. 7 shows a case where the cold air temperature is −20 ° C. and the cold air jet is weak, and (b) shows a case where the cold air temperature is −20 ° C. and the cold air jet is strong for comparison. It is shown. In (a), the temperature boundary layer is not disturbed because the jet of cold air is weak, the surface temperature of the object to be cooled is high, the temperature gradient inside the object to be cooled is small, and quick freezing cannot be performed.

  (B) is a case of the refrigerating apparatus described in Patent Document 1, in which cold air is strongly ejected, the temperature boundary layer is disturbed, the temperature of the surface of the object to be cooled is lowered, and the temperature gradient inside is also compared with (a). And get bigger. However, the temperature difference between the surface of the object to be cooled and the freezing point remains at 7 ° C.

  (C) is a thing of the freezer of a present Example, and is a case where cold air temperature is -40 degreeC and ejection is strong. The temperature difference between the surface of the object to be cooled and the freezing point is 14 ° C, which is about twice that of (b), and the amount of heat transfer inside the object to be cooled is about twice that of (b). The latent heat of freezing generated inside the object to be cooled is quickly removed and quick freezing is performed. Further, (d) shows a case where the cold air temperature is −60 ° C. and the ejection is strong. The temperature difference between the surface of the object to be cooled and the freezing point is 22 ° C., which is about 3 times that in (b), and the amount of heat transfer inside the object to be cooled is about 3 times that in (b). Furthermore, quick freezing can be realized. (B ') and (d') show the temperature distribution when the thickness of the food is twice that of (b) and (d). When the cold air temperature is −20 ° C. (b ′), the temperature gradient inside the object to be cooled becomes small, but when the cold air temperature is −60 ° C. (d ′), the thickness of the object to be cooled Even if it becomes thicker, the temperature gradient inside the food can be kept large, and quick freezing is possible. As described above, by rapidly ejecting cool air having a sufficiently low temperature into the quick freezing chamber 37 at a large flow rate, even a thick object to be cooled can be quickly frozen.

  -Constant-temperature holding operation: The constant-temperature holding operation is an operation in which the temperature increase in the quick freezing chamber 37 and the deep cold storage chamber 38 is suppressed to maintain the constant temperature.

  The control circuit closes the damper 35 and opens the damper 36, so that the cool air flows in the order of the cooler 11, the circulation fan 58, the cold storage container 21, the quick freeze room 37, the deep cold storage room 38, and the cooler 11. Although the cooling capacity from the cooler 11 may be insufficient as in the quick freezing operation, the cold air is sufficiently cooled by contacting the cool storage container 21 as in the quick freezing operation.

(Function / Effect: During defrosting operation)
When the heat pump 10 is in operation, the damper 51 is closed and the damper 52 is opened, and cold air is circulated through the cooler 11 by the circulation fan 58. By the way, due to the circulation of cold air, the object to be cooled such as food and moisture from the environment adhere to the cooler 11 as ice. When the amount of ice attached increases, it becomes a heat transfer resistance and the cooling capacity decreases. Therefore, periodically, for example, once a day, the cooler 11 is heated to 0 ° C. or more to perform a defrosting operation for melting the attached ice. During this defrosting operation, the damper 52 is closed and the damper 51 is opened, so that cold air circulates without passing through the cooler 11. Therefore, even if the temperature of the cooler 11 increases, the first storage chamber is not affected. During the defrosting operation, cooling of the cool air by the cooler 11 is impossible, so the temperature of the cool air is lowered by absorbing heat to the first cool storage member 20 in the cool storage container 21. As described above, since the first cold storage member 20 can absorb a large amount of heat, not only can the temperature in the first storage chamber be maintained, but also the quick freezing operation can be performed even when the cooler is defrosting. Therefore, the temperature fluctuation of the object to be cooled stored in the deep temperature storage chamber 38 can be reduced, and quality deterioration due to the temperature fluctuation can be prevented.

(Function and effect: Use of nighttime power)
FIG. 8 shows an example of an operation method when the nighttime power of the freezer of this embodiment is used. A positive value on the vertical axis represents the heat load on the first storage chamber, and a negative value represents the cooling capacity of the first storage chamber.

  The heat load on the first storage room includes a static load that is substantially constant throughout the day and a dynamic load that changes depending on the use conditions. Examples of the static load include a load due to heating for preventing heat intrusion from outside through the heat insulating material and frosting of the door. Dynamic loads include door opening and closing load due to heat intrusion from outside when the door is opened and closed, deep cooling load by inserting an object to be cooled that is higher in temperature than the first storage room, latent heat of freezing by quick freezing operation, etc. A dynamic load such as a defrosting load that requires a large cooling capacity in a short time such as a quick freezing load and a heater load in a defrosting operation can be exemplified. The dynamic load often occurs in the daytime and is a large load in a short time.

  By the way, according to a contract with an electric power company, for example, at night from 23:00 in the night to 7:00 in the next morning, electric power can be used at an electricity rate of about one third of the daytime. The heat pump 10 is operated with a high cooling capacity of 30 W when the nighttime electricity rate is applied from 23:00 in the night to 7:00 in the next morning, the first cold storage member 20 is solidified, and this first load against the daytime dynamic load. An operation method in which heat is absorbed by melting the cold storage member 20 can be considered.

  Since it is desired to suppress the consumption of electricity as much as possible during the daytime, the heat pump 10 is operated with a cooling capacity as low as about 10 W, which is balanced with a static load. However, the heat pump 10 is stopped for about 2 hours for defrosting the cooler.

  For example, assuming that the cooling efficiency of the heat pump 10 is 1, the power consumption during the night from 23:00 to 7:00 the next morning is 30 W, and the power consumption from 7:00 to 21:00 is 10 W. For example, calculating the daily electricity charge with a daytime electricity charge of 21 yen / kWh and a nighttime electricity charge of 7 yen / kWh would result in 4.62 yen.

  On the other hand, if the heat pump 10 is operated with a constant cooling capacity throughout the day except for about 2 hours when the cooler is defrosted without a night power contract, the power consumption is calculated assuming that the cooling efficiency is 1. It becomes 17.3W, and the electricity bill per day is 7.98 yen. In other words, it becomes possible to use the nighttime power by moving the cooling load necessary for the freezer in time, and it is possible to use the freezer at an electricity rate of about 58% compared to when not using it. is there.

(Modification 1: Configuration)
As shown in FIG. 9, the freezer of this modification has a freezing temperature of −30 in addition to the −60 ° C. first storage chambers 37 and 38 including the quick freezing chamber 37 and the deep temperature storage chamber 38 of the first embodiment. It is a freezer in which the 2nd storage room 39 which is ° C. was installed below. Corresponding to the second storage chamber 39, there is provided a second cold storage container 27 in which a second cold storage member 26 having a melting point of about −30 ° C. or lower is enclosed. As the 2nd cool storage member 26, the aqueous solution (melting | fusing point-37 degreeC) etc. which contain 40 mass% of potassium carbonate etc. are employable. Since the freezing temperature required for the second storage chamber 39 is about −30 ° C., the melting point required for the second cold storage member 26 is desirably a temperature that is not so far from −30 ° C. to −30 ° C.

  The first storage chambers 37 and 38 and the second storage chamber 39 are insulated from each other, and heat-insulating doors 63 and 67 are provided so as to be freely opened and closed. Duct openings 71 and 72 are respectively provided on the downstream side and the upstream side of the cooler 11. The duct opening 71 is connected to the duct opening 73, and the duct opening 72 is connected to the duct opening 74. .

  The part where the duct opening 73 opens, the circulation fan 59, the second cold storage container 27, the second storage chamber 39, the part where the duct opening 74 opens, the part where the duct opening 72 opens, the cooler 11, the duct opening A second circulation path that circulates in the order of the part where the part 71 opens and the part where the duct opening 73 opens is formed.

  A damper 76 is provided on the downstream side of the duct opening 73, and a bypass channel 77 is formed to communicate between a portion where the duct opening 74 opens and a portion where the duct opening 73 opens. A damper 75 is provided at 77.

(Function and effect)
When the dampers 51 and 76 are opened and the dampers 52 and 75 are closed, the cold air cooled by the cooler 11 flows through the second circulation path that flows to the second storage chamber 39 side. As a result, the second cold storage member 26 housed in the second cold storage container 27 is solidified. In this case, it is sufficient for the heat pump 10 to reach a temperature of about −30 ° C. to −40 ° C., so that the operation efficiency can be improved. When the flow of cool air cooled by the cooler 11 flows toward the second storage chamber 39, the cooling can be continued by heat absorption by the first cold storage member 20 on the first storage chambers 37 and 38 side.

  Since the dampers 51 and 76 are closed and the dampers 52 and 75 are opened, the same operational effects as those of the first embodiment can be realized for the first storage chambers 37 and 38. In this case, the second storage chamber 39 can continue to be cooled by heat absorption by the second cold storage member 26.

  Appropriate refrigeration performance can be achieved by switching the dampers 51, 52, 75 and 76 in order so that the storage chambers 37, 38 and 39 can be cooled to the required temperature and / or when quick freezing is performed. It can be demonstrated.

(Modification 2)
As shown in FIG. 10, in the freezer of this modification, in addition to Modification 1, a third storage room 88, which is a refrigerating room having a refrigeration temperature of −2 ° C., is provided above the first storage rooms 37 and 38. Freezer.

  Corresponding to the third storage chamber 88, there is provided a third cold storage container 87 in which a third cold storage member 86 having a melting point of about 0 to 20 ° C. is enclosed. As the third cold storage member 86, ethylene glycol (melting point: -13 ° C) or the like can be adopted.

  The first storage chambers 37 and 38 and the third storage chamber 88 are insulated from each other, and a heat insulating door 89 is provided in the third storage chamber 88 so as to be freely opened and closed. The duct opening 71 provided on the downstream side and the upstream side of the cooler 11 is connected to the duct opening 81, and the duct opening 72 is connected to the duct opening 82.

  The part where the duct opening 81 opens, the circulation fan 85, the third cool storage container 87, the third storage chamber 88, the part where the duct opening 82 opens, the part where the duct opening 72 opens, the cooler 11, the duct opening A third circulation path that circulates in the order of the part where the part 71 opens and the part where the duct opening 81 opens is formed.

  A damper 83 is provided on the downstream side of the duct opening 81, and a bypass flow path is formed to communicate between a portion where the duct opening 81 opens and a portion where the duct opening 82 opens. A damper 84 is provided.

(Function and effect)
When the dampers 51, 75, and 83 are opened and the dampers 52, 76, and 84 are closed, the cold air cooled by the cooler 11 flows through the third circulation path. As a result, the third cold storage member 86 housed in the third cold storage container 87 is solidified. In this case, since it is sufficient for the heat pump 10 to reach a temperature of about -20 ° C, the operation efficiency can be further improved.

  When the flow of the cool air cooled by the cooler 11 flows toward the third storage chamber 88, the first storage chambers 37 and 38, and the first storage member 20 and the second cold storage member on the second storage chamber 39 side. Cooling can be continued by the endothermic heat generated by 26.

  By closing the dampers 51, 76 and 83 and opening the dampers 52, 75 and 84, the same operational effects as those of the first embodiment can be realized for the first storage chambers 37 and 38. In this case, in the second storage chamber 39 and the third storage chamber 88, the cooling can be continued by the heat absorption by the second cool storage member 26 and the third cool storage member 86.

  The dampers 51, 52, 75, 76, 83, and 84 are appropriately switched in order so that each of the storage chambers 37, 38, 39, and 88 can be cooled to a necessary temperature and / or when performing quick freezing. Can demonstrate proper refrigeration performance.

It is a schematic sectional drawing of the freezer of Example 1. FIG. It is a schematic sectional drawing of the freezer of Example 1. FIG. It is a schematic perspective view of the cool storage container which accommodates a cool storage member. It is a schematic perspective view of the cool storage container which accommodates a cool storage member. It is AA sectional drawing of the cool storage container shown in FIG. It is AA sectional drawing of the cool storage container shown in FIG. It is a figure which shows the simulation result of the temperature distribution of the foodstuff in a freezer. It is the figure which showed the example of the method of driving | operating using night electric power. It is a schematic sectional drawing of the freezer of the modification 1. It is a schematic sectional drawing of the freezer of the modification 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Cooler 12 ... Radiator 20 ... 1st cool storage member 21, 27 ... Cold storage container 22, 23, 24 ... Cooling fin 26 ... 2nd cool storage member 31, 32, 33, 34, 43 ... Partition plate 35, 36, 51, 52, 75, 76, 83, 84 ... damper 58, 59, 85 ... circulating fan 71, 72, 73, 74, 81, 82 ... duct opening 37, 38, 39, 88 ... first to third storage Chamber 61, 62 ... Housing body 63, 64, 67, 68, 89, 90 ... Door 86 ... Third cold storage member

Claims (9)

A heat pump that can reach −30 ° C. or lower;
A cooler installed in the heat absorption part of the heat pump;
A first cold storage member having a melting point within a temperature range of −30 ° C. or lower and reachable by the heat pump;
A first storage chamber having a space for storing a first object to be cooled therein;
A circulation path for circulating cold air in the order of the cooler, the first cold storage member, the first storage chamber, and the cooler;
By connecting between the downstream side of the cooler and the upstream side of the first cool storage member and the downstream side of the first storage chamber and the upstream side of the cooler in the circulation path, A bypass means for separating the cold storage member and the first storage chamber from the cooler;
Defrosting means for adjusting the temperature of the cooler and defrosting when the circulation path is separated by the bypass means;
A freezer comprising a circulation fan for circulating the cold air in the circulation path. A second storage chamber having a space for storing a second object to be cooled, and a melting point at a temperature higher than that of the first cold storage member disposed at a position upstream of the second storage chamber or the second storage chamber. A second regenerator member having
The freezer according to claim 1, wherein the second storage chamber and the second cold storage member are connected to the circulation path at a position parallel to the first storage chamber.   The freezer according to claim 2, wherein the second storage chamber and the second cold storage member are connected to the circulation path at a position parallel to the first cold storage member and the first storage chamber. The circulation path has a circulation path switching means for switching the flow of the cold air between the first storage chamber and the second storage chamber,
The heat pump switches operation between the first storage chamber and the second storage chamber so that the temperature reached by the cooler becomes appropriate as the cooling air flow is switched by the circulation path switching means. The freezer according to claim 2 or 3. A second storage chamber having a space for storing a second object to be cooled, and a melting point at a temperature higher than that of the first cold storage member disposed at a position upstream of the second storage chamber or the second storage chamber. A second regenerator member having
The freezer according to claim 1, wherein the second storage chamber and the second cold storage member are connected to the circulation path at a position downstream of the first storage chamber.   The first regenerator member and / or the second regenerator member comprises a mixture of ethylene glycol and water, a mixture of propylene glycol and water, a mixture of ethanol and water, a mixture of potassium carbonate and water, and a mixture of calcium chloride and water. The freezer according to claim 1 which is any one of the above. A third storage chamber having a space for storing the third object to be cooled, and a melting point at a temperature higher than that of the second cold storage member disposed in the third storage chamber or at a position upstream of the third storage chamber. A third regenerator member having
The said 3rd storage chamber and the said 3rd cool storage member are connected to the said circulation path in the position of a parallel position or a downstream side with respect to the said 2nd storage chamber. freezer.   The freezer according to claim 7, wherein the third cold storage member is any one of ethylene glycol, propylene glycol, and a mixture of sodium chloride and water.   The first cold storage member, the second cold storage member, and / or the third cold storage member has an outer box and a heat storage fin that is in contact with the outer box and disposed in the outer box. The freezer according to any one of claims 1 to 8, which is stored inside the storage case.

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