JP2024078818A - Cooling device and cooling method - Google Patents

Abstract

To provide a cooling device which can stably maintain a minus temperature zone and a high-humidity environment, and a cooling method.SOLUTION: A cooling device 1 for cooling food in a refrigerator at high humidity in a minus temperature zone has a plurality of cooling coils 51, 61 for cooling air in the refrigerator by a refrigerant which circulates in the cooling device, and a plurality of fans 10, 20 for blowing air toward the plurality of cooling coils by taking in the air in the refrigerator in which the food is cooled at high humidity.SELECTED DRAWING: Figure 2A

Description

The present invention relates to a cooling device and a cooling method, and in particular to a cooling device and a cooling method for cooling food at a negative temperature and with high humidity.

After harvest, most fruits and vegetables deteriorate through respiration, drying, changes in composition, and putrefaction by microorganisms. In other words, quality (freshness) can be maintained for a long period of time by suppressing all of these. On the other hand, the proliferation of microorganisms such as bacteria and mold can be suppressed by lowering temperature and humidity, but lowering the humidity of fruits and vegetables is not recommended as it leads to drying out. For this reason, it is desirable to store fruits and vegetables at low temperatures where microorganisms cannot reproduce, while maintaining a high humidity environment and suppressing respiration and changes in composition, without causing the fruits and vegetables to dry out or freeze.

As a method of high humidity cooling, refrigerated storage units equipped with a refrigerator and a humidifier have been put to practical use. The refrigerator is composed of, for example, a compressor, a condenser, an expansion valve, and an evaporator. The humidifier is not particularly limited, but for example, a water spray type humidifier.

In such a refrigerated storage unit, vegetables and other items are stored inside the storage unit, the air inside the storage unit is cooled by the refrigerant of the freezer, and the cold air is forced to circulate by a fan to cool the vegetables and other items. At this time, a humidifier sprays water to maintain a high humidity level inside the storage unit.

Another method of high humidity cooling is the gas-liquid contact system, which cools by contacting cold air with antifreeze sprayed into a cooler or circulated through a cooler.

JP 2015-175553 A

Among fruits and vegetables, vegetables and fruits with high sugar content will not freeze even if stored at -2 to -1°C. Meat will drip when thawed if stored frozen, compromising its quality, but if stored at -2 to -1°C, it will not freeze and its quality will be maintained, and the yield after processing will also improve. In other words, if a high humidity environment in the negative temperature range (above the freezing point of the target food and below 0°C, and with a relative humidity of 85% or more) can be achieved, it will be possible to further suppress the growth of microorganisms, respiration of fruits and vegetables and foods, and changes in their components, and it is believed that this will enable fruits and vegetables and foods to be stored for longer periods with higher quality. However, it is known to be extremely difficult to stably maintain a high humidity environment in the negative temperature range.

For example, when trying to maintain high humidity conditions in the negative temperature range using conventional technology, in the case of humidification cooling, the evaporation temperature of the cooling device must be kept below 0°C, which causes frost to form on the cooling coil, reducing the relative humidity and cooling capacity. Periodic defrosting is required to remove this, during which the temperature inside the cabinet rises. Also, the water in the humidification device freezes, so a heater or other treatment is required. Another problem is that below 0°C, the mist does not easily turn into water vapor, and the relative humidity does not increase. On the other hand, in the case of the gas-liquid contact type, the humidity in the air decreases as the concentration of the antifreeze increases, and a water tank, pump, watering nozzles, etc. are required, which means that the equipment costs are higher than with humidification cooling.

The present invention was invented to solve the above problems, and aims to provide a cooling device and cooling method that can stably maintain a negative temperature and high humidity environment.

The cooling device of the present invention, which achieves the above-mentioned objective, is a cooling device that cools food in a refrigerator at a high humidity in the negative temperature range, and has multiple cooling coils for cooling the air in the refrigerator using a refrigerant that circulates through the cooling device, and multiple fans that take in the air in the refrigerator that has cooled the food at a high humidity and blow it toward each of the multiple cooling coils.

The cooling method according to the present invention, which achieves the above-mentioned objective, is a cooling method for cooling food in a refrigerator at a negative temperature range with high humidity, and in a refrigeration cycle having multiple cooling coils for cooling the air circulating in the refrigerator by a refrigerant circulating in a cooling device, one of the cooling coils performs a cooling operation and the other cooling coil performs a defrosting operation.

According to the cooling device and cooling method described above, even if one of the cooling coils is performing a cooling operation, the other cooling coil can perform a defrosting operation, so that a cooling device and cooling method can be provided that can stably maintain a negative temperature and high humidity environment for a long period of time.

FIG. 2 is a schematic diagram showing a flow of a refrigerant in a cooling device according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing a cooling device according to a first embodiment of the present invention, illustrating a state in which a cooling operation is performed on the first cooling coil side. FIG. 2 is a schematic diagram showing the cooling device according to the first embodiment of the present invention, illustrating a state in which a cooling operation is performed on the second cooling coil side. FIG. 11 is a schematic diagram showing a cooling device according to a second embodiment of the present invention, illustrating a state in which a cooling operation is performed on the first cooling coil side. FIG. 11 is a schematic diagram showing a cooling device according to a second embodiment of the present invention, illustrating a state in which a cooling operation is performed on the second cooling coil side. FIG. 11 is a schematic diagram showing a cooling device according to a third embodiment of the present invention, illustrating a state in which a cooling operation is performed on the first cooling coil side. FIG. 11 is a schematic diagram showing a cooling device according to a third embodiment of the present invention, illustrating a state in which a cooling operation is performed on the second cooling coil side. 1 is a schematic diagram showing a situation in which a microchannel heat exchanger is arranged at an angle to the vertical direction and a fan blows sideways. FIG. FIG. 1 is a schematic diagram showing a state in which a microchannel heat exchanger is arranged at an angle to the vertical direction and a fan blows downward. FIG. 1 is a schematic diagram showing a horizontally oriented microchannel heat exchanger.

First Embodiment
A cooling device 1 according to a first embodiment of the present invention will be described with reference to Figures 1, 2A, and 2B. In the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions will be omitted. The dimensional ratios in the drawings are exaggerated for the convenience of explanation, and may differ from the actual ratios.

Figure 1 is a schematic diagram showing the flow of refrigerant in a cooling device 1 according to an embodiment of the present invention. Figures 2A and 2B are schematic diagrams showing a cooling device 1 according to a first embodiment of the present invention.

The cooling device 1 according to this embodiment is a device for cooling food in a refrigerator at a negative temperature and high humidity. The temperature inside the refrigerator varies depending on the food being stored, but is set to, for example, -2 to -1°C, and the humidity inside the refrigerator is, for example, 85% or higher.

As shown in Figures 1, 2A, and 2B, the cooling device 1 according to the first embodiment has a first fan 10, a second fan 20, a first prefilter 30, a second prefilter 40, a first refrigeration cycle 50, a second refrigeration cycle 60, a housing 70, and a first static pressure sensor 81 to a fourth static pressure sensor 84. Each component will be described below.

As shown in Figures 2A and 2B, the first fan 10 is provided upstream of the air flow of the first cooling coil 51 of the first refrigeration cycle 50. That is, the first fan 10 takes in the air inside the refrigerator after cooling the food to a high humidity level, and blows it toward the first cooling coil 51 of the first refrigeration cycle 50.

It is preferable to use a centrifugal fan rather than an axial fan as the first fan 10. By using a centrifugal fan, the variation in the front wind speed of the air passing through the first cooling coil 51 can be suppressed, and the entire surface of the first cooling coil 51 can be used efficiently as an evaporator.

The first fan 10 may be arranged so that the direction of the rotation axis is horizontal, as shown in FIG. 5A, or may be arranged so that the direction of the rotation axis is vertical, as shown in FIG. 5B.

As shown in Figures 2A and 2B, the second fan 20 is provided upstream of the air flow of the second cooling coil 61 of the second refrigeration cycle 60. In other words, the second fan 20 takes in the air inside the refrigerator after cooling the food to a high humidity level, and blows it toward the second cooling coil 61 of the second refrigeration cycle 60.

It is preferable to use a centrifugal fan rather than an axial fan for the second fan 20. By using a centrifugal fan, it is possible to suppress the variation in the wind speed at the front of the air passing through the second cooling coil 61, and it is possible to efficiently use the entire surface of the second cooling coil 61 as an evaporator.

The second fan 20 may be arranged so that the direction of the rotation axis is horizontal, as shown in FIG. 5A, or so that the direction of the rotation axis is vertical, as shown in FIG. 5B.

The first fan 10 and the second fan 20 are arranged inside the housing 70.

As shown in Figs. 2A and 2B, the first prefilter 30 is provided upstream of the air flow of the first cooling coil 51 of the first refrigeration cycle 50 and downstream of the first fan 10. The first prefilter 30 collects dust and rectifies the air moving inside the housing 70. For example, a nonwoven fabric filter can be used as the first prefilter 30.

The first prefilter 30 is arranged so as to be inclined with respect to the vertical direction, as shown in Figs. 5A and 5B. The first prefilter 30 is arranged so as to be approximately parallel to the first cooling coil 51, as shown in Figs. 5A and 5B.

2A and 2B, the second prefilter 40 is provided upstream of the air flow of the second cooling coil 61 of the second refrigeration cycle 60 and downstream of the second fan 20. The second prefilter 40 collects dust and straightens the air moving inside the housing 70. For example, a nonwoven fabric filter can be used as the second prefilter 40.

The second prefilter 40 is arranged so as to be inclined with respect to the vertical direction, as shown in Figs. 5A and 5B. The second prefilter 40 is arranged so as to be approximately parallel to the second cooling coil 61, as shown in Figs. 5A and 5B.

The first prefilter 30 and the second prefilter 40 are disposed inside the housing 70.

As shown in Figures 2A and 2B, the first refrigeration cycle 50 has a first cooling coil 51 as an evaporator, a first compressor 52, a first condenser 53, a first receiver 54, a first expansion valve 55, a first evaporation pressure control valve 56, a first circulation line 57, and a first hot gas bypass flow path 90 (see Figure 1).

In the first cooling coil 51, the refrigerant evaporated by cooling the air taken in by the first fan 10 is compressed by the first compressor 52, and the high-temperature, high-pressure refrigerant is cooled and condensed in the first condenser 53. The condensed refrigerant is stored in the first receiver 54 and sent from the first receiver 54 to the first expansion valve 55 where it is expanded. The expanded refrigerant is sent to the first cooling coil 51 and used to cool the air taken in by the first fan 10.

The first cooling coil 51 is disposed inside the first region 71 of the housing 70, as shown in Figures 2A and 2B. The first cooling coil 51 is a microchannel heat exchanger. With this configuration, the fin pitch is narrow and the cooling area per unit volume is large, making it easy to keep the temperature difference ΔT between the temperature of the air sucked in from inside the cabinet and the evaporation temperature as small as possible, and even in the negative temperature range, dehumidification of the air passing through the first cooling coil 51 can be suitably suppressed. The first cooling coil 51 can also be made smaller.

As shown in Figures 5A and 5B, the first cooling coil 51 is arranged to be inclined with respect to the vertical direction. With this configuration, accumulation of condensed water on the microchannel heat exchanger, which causes freezing, can be effectively suppressed during cooling operation, and frozen condensed water can be melted and then allowed to fall downward by gravity during defrosting operation, so that freezing on the first cooling coil 51 can be effectively suppressed after the cooling operation is resumed. Note that the angle at which the first cooling coil 51 is inclined with respect to the vertical direction is preferably 45 to 90 degrees. With this configuration, by increasing the inclination, water adhering to the fins of the microchannel heat exchanger can be more effectively allowed to fall downward by gravity.

The refrigerant circulating through the first refrigeration cycle 50 may be, for example, fluorocarbon or _CO2 , but is not particularly limited thereto.

The first evaporation pressure regulating valve 56 maintains the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the first cooling coil 51, thereby suppressing dehumidification of the air inside the storage unit in the negative temperature range.

2A and 2B, the second refrigeration cycle 60 has a second cooling coil 61 as an evaporator, a second compressor 62, a second condenser 63, a second receiver 64, a second expansion valve 65, a second evaporation pressure control valve 66, a second circulation line 67, and a second hot gas bypass flow path 91 (see FIG. 1). The second compressor 62 of the second refrigeration cycle 60 is also used as the first compressor 52 of the first refrigeration cycle 50. The second condenser 63 of the second refrigeration cycle 60 is also used as the first condenser 53 of the first refrigeration cycle 50. The second receiver 64 of the second refrigeration cycle 60 is also used as the first receiver 54 of the first refrigeration cycle 50. It should be noted that they may not be used together and may be provided separately.

In the second cooling coil 61, the refrigerant evaporated by cooling the air taken in by the second fan 20 is compressed by the second compressor 62, and the high-temperature, high-pressure refrigerant is cooled and condensed in the second condenser 63. The condensed refrigerant is stored in the second receiver 64 and sent from the second receiver 64 to the second expansion valve 65 where it is expanded. The expanded refrigerant is sent to the second cooling coil 61 and used to cool the air taken in by the second fan 20.

The second cooling coil 61 is disposed inside the second region 72 of the housing 70, as shown in Figures 2A and 2B. The second cooling coil 61 is a microchannel heat exchanger. With this configuration, the fin pitch is narrow and the cooling area per unit volume is large, making it easy to keep the temperature difference ΔT between the temperature of the air sucked in from inside the cabinet and the evaporation temperature as small as possible, and even in the negative temperature range, dehumidification of the air passing through the second cooling coil 61 can be suitably suppressed. The second cooling coil 61 can also be made smaller.

As shown in Figures 5A and 5B, the second cooling coil 61 is arranged so as to be inclined with respect to the vertical direction. With this configuration, accumulation of condensed water on the microchannel heat exchanger can be suitably suppressed during cooling operation, and frozen condensed water can be melted and then allowed to fall downward by gravity during defrosting operation, so that freezing on the second cooling coil 61 can be suitably suppressed after the cooling operation is resumed. Note that the angle at which the second cooling coil 61 is inclined with respect to the vertical direction is preferably 45 to 90 degrees. With this configuration, by increasing the inclination, water adhering to the fins of the microchannel heat exchanger can be more suitably allowed to fall downward by gravity.

The refrigerant circulating through the second refrigeration cycle 60 may be, but is not limited to, freon or _CO2 .

The second evaporation pressure adjustment valve 66 maintains the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the second cooling coil 61, thereby suppressing dehumidification of the air inside the storage unit in the negative temperature range.

As shown in Figures 2A and 2B, the housing 70 has a first region 71 in which the first fan 10, the first prefilter 30, and the first cooling coil 51 are arranged, a second region 72 in which the second fan 20, the second prefilter 40, and the second cooling coil 61 are arranged, and a mixing region 73 in which the air that has passed through the first cooling coil 51 and the air that has passed through the second cooling coil 61 are mixed.

In the mixing area 73, the air that has passed through the first cooling coil 51 during cooling operation and the air that has passed through the second cooling coil 61 during defrosting operation are mixed (see FIG. 2A). At this time, in the first cooling coil 51, dehumidification during cooling is suitably suppressed, while in the second cooling coil 61, water melted by defrosting adheres to the fins, so the air that has passed through each coil maintains a high humidity state, and these are mixed in the mixing area 73 to generate high-humidity cooled air. In addition, in the mixing area 73, the air that has passed through the second cooling coil 61 during cooling operation and the air that has passed through the first cooling coil 51 during defrosting operation are mixed (see FIG. 2B). At this time, in the second cooling coil 61, dehumidification during cooling is suitably suppressed, while in the first cooling coil 51, water melted by defrosting adheres to the fins, so the air that has passed through each coil maintains a high humidity state, and these are mixed in the mixing area 73 to generate high-humidity cooled air.

The housing 70 is preferably constructed with insulated walls.

The first static pressure sensor 81 to the fourth static pressure sensor 84 are provided to switch between cooling operation and de-icing operation of the first cooling coil 51 and the second cooling coil 61.

As shown in Figures 2A and 2B, the first static pressure sensor 81 is provided upstream of the first cooling coil 51. The second static pressure sensor 82 is provided downstream of the first cooling coil 51. The first static pressure sensor 81 and the second static pressure sensor 82 are disposed within the first region 71 of the housing 70.

The third static pressure sensor 83 is provided upstream of the second cooling coil 61, as shown in Figures 2A and 2B. The fourth static pressure sensor 84 is provided downstream of the second cooling coil 61. The third static pressure sensor 83 and the fourth static pressure sensor 84 are disposed within the second region 72 of the housing 70.

The static pressure rise of the first cooling coil 51 can be measured by subtracting the value measured by the second static pressure sensor 82 from the value measured by the first static pressure sensor 81. Also, the static pressure rise of the second cooling coil 61 can be measured by subtracting the value measured by the fourth static pressure sensor 84 from the value measured by the third static pressure sensor 83.

For example, when the difference between the value measured by the first static pressure sensor 81 and the value measured by the second static pressure sensor 82 during cooling operation on the first cooling coil 51 side becomes 160 Pa or more from 60-80 Pa, it is determined that ice has formed on the first cooling coil 51, and the first cooling coil 51 side is switched to de-icing operation.

On the other hand, when the cooling operation is being performed on the second cooling coil 61 side, if the difference between the value measured by the third static pressure sensor 83 and the value measured by the fourth static pressure sensor 84 becomes 160 Pa or more from 60 to 80 Pa, it is determined that ice has formed on the second cooling coil 61, and the second cooling coil 61 side is switched to de-icing operation.

Next, the flow of refrigerant in the cooling device 1 according to this embodiment will be described with reference to FIG.

The refrigerant coming out of the first condensing unit (corresponding to the first compressor 52, the first condenser 53, and the first receiver 54) passes through the first expansion valve 55 and flows to the first cooling coil 51. The refrigerant that has passed through the first cooling coil 51 merges with the first hot gas bypass flow path 90, which guides a portion of the refrigerant (hot gas) compressed by the first compressor 52 from downstream of the first compressor 52 to upstream of the first evaporation pressure regulating valve 56, passes through the first evaporation pressure regulating valve 56, and then returns to the first condensing unit.

The refrigerant coming out of the second condensing unit (corresponding to the second compressor 62, the second condenser 63, and the second receiver 64) passes through the second expansion valve 65 and flows to the second cooling coil 61. The refrigerant that has passed through the second cooling coil 61 merges with the second hot gas bypass flow path 91, which guides a portion of the refrigerant (hot gas) compressed by the second compressor 62 from downstream of the second compressor 62 to upstream of the second evaporation pressure regulating valve 66, passes through the second evaporation pressure regulating valve 66, and then returns to the second condensing unit.

In order to effectively utilize the entire surfaces of the first cooling coil 51 and the second cooling coil 61, the opening of the first expansion valve 55 and the second expansion valve 65 is adjusted based on the degree of superheat calculated by the temperature sensors 92, 93 after the first and second hot gas bypass flow paths 90, 91 join and the pressure sensors 94, 95 located upstream of the joining point of the first and second hot gas bypass flow paths 90, 91. Specifically, the opening of the first expansion valve 55 and the second expansion valve 65 is adjusted so that the steam at the outlet of the first cooling coil 51 and the second cooling coil 61 is as wet as possible while ensuring the degree of superheat by controlling the amount of hot gas flowing through the first and second hot gas bypass flow paths 90, 91 with the adjustment valves 96, 97.

Next, the cooling method of the cooling device 1 according to the first embodiment will be described with reference to Figures 2A and 2B. Figure 2A is a diagram showing a state in which a cooling operation is performed on the first cooling coil 51 side and a defrosting operation is performed on the second cooling coil 61 side, and Figure 2B is a diagram showing a state in which a cooling operation is performed on the second cooling coil 61 side and a defrosting operation is performed on the first cooling coil 51 side.

First, in the first refrigeration cycle 50 and the second refrigeration cycle 60, the refrigerant is circulated to perform cooling operation inside the storage unit (first operating state). At that time, the set temperature inside the storage unit during cooling operation is set to 0°C or higher.

After the first operating state continues for a predetermined time, the first refrigeration cycle 50 stops operating, and the second refrigeration cycle 60 starts cooling operation. After that, if ice formation on the second cooling coil 61 is confirmed, as shown in FIG. 2A, cooling operation starts on the first cooling coil 51 side, and de-icing operation is performed on the second cooling coil 61 side (second operating state). As described above, the method for confirming ice formation is to measure differential pressure using the static pressure sensors 81-84.

In cooling operation on the first cooling coil 51 side, the first evaporation pressure regulating valve 56 is controlled to maintain the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the first cooling coil 51, thereby minimizing the temperature difference ΔT between the surface temperature (evaporation temperature) of the first cooling coil 51 and the temperature of the air taken in (suction temperature). By reducing the temperature difference ΔT in this way, it is possible to effectively suppress dehumidification of the air inside the storage unit that accompanies cooling as it passes through the first cooling coil 51, and it is possible to maintain high humidity (e.g., 85% or higher) even in the negative temperature range.

In the defrosting operation on the second cooling coil 61 side, the defrosting operation is performed without stopping the supply of refrigerant. Specifically, the second cooling coil 61 is operated with the refrigerant evaporation temperature in the range of 0 to 3°C to defrost. In the defrosting operation, the second evaporation pressure regulating valve 66 is controlled to increase the evaporation pressure in the second cooling coil 61, increasing the saturation temperature of the refrigerant, and defrosting the second cooling coil 61 by warming it from the inside. At this time, if the suction temperature is lower than the evaporation temperature, the refrigerant does not evaporate, the degree of superheat becomes 0, the second expansion valve 65 is fully closed, and the refrigerant does not flow through the cooling coil 61. Therefore, the minimum opening (for example, 10% or less) is set to prevent the second expansion valve 65 from fully closing.

In the second operating state, air is sent to the second cooling coil 61 to which some of the drain water melted by the defrosting operation in the second cooling coil 61 is attached, causing the drain water to evaporate, and the drain water is then mixed in the mixing area 73 with the air that has passed through the first cooling coil 51 by the cooling operation of the first refrigeration cycle 50, generating high-humidity cooled air, which allows the food inside the refrigerator to be cooled with high humidity.

Furthermore, according to this embodiment, high humidity cooling air can be generated in the negative temperature range with a simple device configuration.

Next, after the defrosting operation on the second cooling coil 61 side in the second operating state is completed, defrosting operation is performed on the first cooling coil 51 side and cooling operation is performed on the second cooling coil 61 side (third operating state) as shown in FIG. 2B. Switching from the second operating state to the third operating state can be determined by fluctuations in differential pressure using the static pressure sensors 81-84 as described above.

In cooling operation on the second cooling coil 61 side, the second evaporation pressure regulating valve 66 is controlled to maintain the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the second cooling coil 61, thereby minimizing the temperature difference ΔT between the surface temperature (evaporation temperature) of the second cooling coil 61 and the temperature of the air taken in (suction temperature). By reducing the temperature difference ΔT in this way, it is possible to effectively suppress dehumidification of the air inside the storage unit that accompanies cooling as it passes through the second cooling coil 61, and it is possible to maintain high humidity (e.g., 85% or higher) even in the negative temperature range.

In the defrosting operation on the first cooling coil 51 side, the defrosting operation is performed without stopping the supply of refrigerant. Specifically, the first cooling coil 51 is operated with the evaporation temperature of the refrigerant in the range of 0 to 3°C to defrost. In the defrosting operation, the first evaporation pressure regulating valve 56 is controlled to increase the evaporation pressure in the first cooling coil 51, increasing the saturation temperature of the refrigerant, and defrosting the first cooling coil 51 by warming it from the inside. At this time, if the suction temperature is lower than the evaporation temperature, the refrigerant does not evaporate, the degree of superheat becomes 0, the first expansion valve 55 is fully closed, and the refrigerant does not flow through the cooling coil 51. Therefore, the minimum opening (for example, 10% or less) is set to prevent the first expansion valve 55 from being fully closed.

In the third operating state, air is sent to the first cooling coil 51 to which some of the drain water melted by the defrosting operation in the first cooling coil 51 is attached, causing the drain water to evaporate, and the drain water is then mixed in the mixing area 73 with the air that has passed through the second cooling coil 61 by the cooling operation of the second refrigeration cycle 60, generating high-humidity cooled air, which allows the food inside the refrigerator to be cooled with high humidity.

Next, if ice formation on the first cooling coil is confirmed in the third operating state, the third operating state is switched to the second operating state. Switching from the third operating state to the second operating state can be determined by fluctuations in differential pressure using static pressure sensors 81-84 as described above. Thereafter, the second operating state and the third operating state are alternately repeated. With this method, switching can be performed immediately if ice formation occurs, making it possible to continuously and stably supply high humidity cooled air to the interior of the storage facility.

As described above, the cooling device 1 according to the first embodiment is a cooling device 1 that cools food in a refrigerator at a negative temperature and high humidity. The cooling device 1 has a first cooling coil 51 and a second cooling coil 61 for cooling the air in the refrigerator by a refrigerant circulating in the cooling device 1, and a first fan 10 and a second fan 20 for taking in the air in the refrigerator that has cooled the food at a high humidity and blowing it toward the first cooling coil 51 and the second cooling coil 61. With the cooling device 1 configured in this way, one cooling coil (e.g., the first cooling coil 51) performs a cooling operation, and the other cooling coil (e.g., the second cooling coil 61) performs a defrosting operation alternately, so that a negative temperature and high humidity environment can be stably maintained.

The first cooling coil 51 and the second cooling coil 61 are microchannel heat exchangers. With the cooling device 1 configured in this way, it is possible to ensure a sufficient cooling area, and by keeping the temperature difference ΔT between the suction temperature and the evaporation temperature as small as possible, it is possible to achieve high humidity even in the negative temperature range.

The microchannel heat exchanger is also positioned at an angle to the vertical direction. With the cooling device 1 configured in this way, water that is attached to and held on the fins of the microchannel heat exchanger can be allowed to fall downward by gravity during the defrosting operation, so that freezing in the first cooling coil 51 can be effectively suppressed when the cooling operation is performed after the defrosting operation is completed.

The angle at which the microchannel heat exchanger is inclined relative to the vertical is 45 to 90 degrees. With the cooling device 1 configured in this way, water that is attached to and held on the fins of the microchannel heat exchanger can be more effectively allowed to fall downward by gravity during the defrosting operation, and therefore freezing in the first cooling coil 51 can be more effectively prevented when the cooling operation is performed after the defrosting operation is completed.

The first fan 10 and the second fan 20 are centrifugal fans. With the cooling device 1 configured in this way, the variation in the front wind speed of the air passing through the first cooling coil 51 and the second cooling coil 61 can be suppressed, and the entire surfaces of the first cooling coil 51 and the second cooling coil 61 can be used efficiently as evaporators.

The cooling device 1 further includes a mixing area 73 that is provided downstream of the first cooling coil 51 and the second cooling coil 61 and generates high humidity cooling air by mixing the air that has passed through the cooling coil on the cooling operation side and the air that has passed through the cooling coil on the defrosting operation side. With the cooling device 1 configured in this manner, the simple device configuration makes it easy to switch operating states, and it is possible to stably maintain an environment in the negative temperature range and a relative humidity of 85% or higher.

As described above, the cooling method of the cooling device 1 according to this embodiment is a cooling method for cooling food in the refrigerator at a negative temperature and high humidity, and includes a first refrigeration cycle 50 and a second refrigeration cycle 60, each of which includes a first cooling coil 51 and a second cooling coil 61 for cooling the air circulating in the refrigerator by the refrigerant circulating in the cooling device 1. The first cooling coil 51 performs a cooling operation, and the second cooling coil 61 performs a defrosting operation. This cooling method makes it possible to stably maintain an environment in the negative temperature range and a relative humidity of 85% or more.

Second Embodiment
Next, the configuration of a cooling device 2 according to a second embodiment will be described with reference to FIGS. 3A and 3B.

Figures 3A and 3B are schematic diagrams showing a cooling device 2 according to a second embodiment of the present invention.

Explanations of parts common to the first embodiment will be omitted, and only features unique to the second embodiment will be explained. Note that the same members as those in the first embodiment described above will be denoted by the same reference numerals, and duplicate explanations will be omitted. The second embodiment differs from the first embodiment in the configuration of the housing, etc.

As shown in Figures 3A and 3B, the cooling device 2 according to the second embodiment has a first fan 10, a second fan 20, a first prefilter 30, a second prefilter 40, a first refrigeration cycle 50, a second refrigeration cycle 60, a first housing 170, a second housing 180, and a first static pressure sensor 81 to a fourth static pressure sensor 84. The first fan 10, the second fan 20, the first prefilter 30, the second prefilter 40, the first refrigeration cycle 50, the second refrigeration cycle 60, and the first static pressure sensor 81 to the fourth static pressure sensor 84 have the same configuration as the cooling device 1 according to the first embodiment described above, and therefore a description thereof will be omitted.

The first housing 170 is disposed inside the second housing 180. As shown in Figures 3A and 3B, the first housing 170 has a first region 171 in which the first fan 10, the first prefilter 30, and the first cooling coil 51 are disposed, and a second region 172 in which the second fan 20, the second prefilter 40, and the second cooling coil 61 are disposed.

In the first region 171 of the first housing 170, a first outlet region 173 is formed downstream of the first cooling coil 51. In the first outlet region 173, as shown in Figs. 3A and 3B, a first opening/closing device 11 capable of switching between communication and cut-off with the interior of the storage unit, and a second opening/closing device 12 capable of switching between communication and cut-off with a mixing region 181 formed at the most upstream of the second housing 180 are arranged. The opening/closing device is not particularly limited, but for example, a damper valve can be used.

In the second region 172 of the first housing 170, a second outlet region 174 is formed downstream of the second cooling coil 61. In the second outlet region 174, as shown in Figures 3A and 3B, a third opening/closing device 13 capable of switching between communication and cut-off with the interior of the storage unit and a fourth opening/closing device 14 capable of switching between communication and cut-off with a mixing region 181 formed at the most upstream of the second housing 180 are arranged.

The second housing 180 is formed to surround the first housing 170. As shown in Figs. 3A and 3B, the second housing 180 is provided upstream of the first cooling coil 51 and the second cooling coil 61, and has a mixing area 181 in which the air taken in by the first fan 10 and the second fan 20 and the high humidity air generated by sending air to the second cooling coil 61 during defrosting operation are mixed, a first return flow path 182 connecting the first outlet area 173 and the mixing area 181, and a second return flow path 183 connecting the second outlet area 174 and the mixing area 181.

Next, the cooling method of the cooling device 2 according to the second embodiment will be described with reference to Figures 3A and 3B. Figure 3A is a diagram showing a state in which a cooling operation is performed on the first cooling coil 51 side and a defrosting operation is performed on the second cooling coil 61 side, and Figure 3B is a diagram showing a state in which a cooling operation is performed on the second cooling coil 61 side and a defrosting operation is performed on the first cooling coil 51 side.

First, in the first refrigeration cycle 50 and the second refrigeration cycle 60, the refrigerant is circulated to perform cooling operation inside the storage unit (first operating state). At that time, the set temperature inside the storage unit during cooling operation is set to 0°C or higher.

After the first operating state continues for a predetermined time, the first refrigeration cycle 50 stops operating, and the second refrigeration cycle 60 starts cooling operation. After that, when ice formation on the second cooling coil 61 is confirmed, as shown in FIG. 3A, cooling operation starts on the first cooling coil 51 side, and de-icing operation is performed on the second cooling coil 61 side (second operating state).

In cooling operation on the first cooling coil 51 side, the first evaporation pressure regulating valve 56 is controlled to maintain the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the first cooling coil 51, thereby minimizing the temperature difference ΔT between the surface temperature (evaporation temperature) of the first cooling coil 51 and the temperature of the air taken in (suction temperature). By reducing the temperature difference ΔT in this way, it is possible to effectively suppress dehumidification of the air inside the storage unit that accompanies cooling as it passes through the first cooling coil 51, and it is possible to maintain high humidity (e.g., 85% or higher) even in the negative temperature range.

During cooling operation on the first cooling coil 51 side, the first opening/closing device 11 is opened to connect the first outlet area 173 to the inside of the cabinet, and the second opening/closing device 12 is closed to isolate the first outlet area 173 from the mixing area 181. As a result, the air cooled in the first cooling coil 51 is blown out from the first outlet area 173 through the first opening/closing device 11 into the cabinet.

In the de-icing operation on the second cooling coil 61 side, the de-icing operation is performed without stopping the supply of refrigerant. Specifically, de-icing is performed in the second cooling coil 61 by operating the coil with the refrigerant evaporation temperature in the range of 0 to 3°C. In the de-icing operation, the second evaporation pressure adjustment valve 66 is controlled to increase the evaporation pressure in the second cooling coil 61, increasing the saturation temperature of the refrigerant, and de-icing the second cooling coil 61 by heating it from the inside.

During the defrosting operation on the second cooling coil 61 side, the third opening/closing device 13 is closed to isolate the second outlet area 174 from the inside of the refrigerator, and the fourth opening/closing device 14 is opened to connect the second outlet area 174 to the mixing area 181. As a result, in the second operating state, air is sent to the second cooling coil 61 to which the drain water melted by the defrosting operation of the second cooling coil 61 is attached, causing the drain water to evaporate and generating high humidity air, which returns to the mixing area 181 via the second return flow path 183. Then, in the mixing area 181, the air is mixed with the air inside the refrigerator sucked in by the first fan 10 to generate high humidity cooled air, which allows the food inside the refrigerator to be cooled with high humidity.

Next, after the de-icing operation on the second cooling coil 61 side in the second operating state is completed, de-icing operation is performed on the first cooling coil 51 side, and cooling operation is performed on the second cooling coil 61 side (third operating state), as shown in FIG. 3B.

In cooling operation on the second cooling coil 61 side, the second evaporation pressure regulating valve 66 is controlled to maintain the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the second cooling coil 61, thereby operating so as to minimize the temperature difference ΔT between the surface temperature (evaporation temperature) of the second cooling coil 61 and the temperature of the air taken in (suction temperature). By reducing the temperature difference ΔT in this way, it is possible to effectively suppress dehumidification that accompanies cooling when passing through the second cooling coil 61, and it is possible to maintain high humidity (e.g., 85% or higher) even in the negative temperature range.

During cooling operation on the second cooling coil 61 side, the third opening/closing device 13 is opened to connect the second outlet area 174 to the inside of the cabinet, and the fourth opening/closing device 14 is closed to isolate the second outlet area 174 from the mixing area 181. As a result, the air cooled in the second cooling coil 61 is blown out from the second outlet area 174 through the third opening/closing device 13 into the cabinet.

In the de-icing operation on the first cooling coil 51 side, the de-icing operation is performed without stopping the supply of refrigerant. Specifically, de-icing is performed in the first cooling coil 51 by operating the refrigerant at an evaporation temperature in the range of 0 to 3°C. In the de-icing operation, the first evaporation pressure regulating valve 56 is controlled to increase the evaporation pressure in the first cooling coil 51, increasing the saturation temperature of the refrigerant, and de-icing the first cooling coil 51 by heating it from the inside.

During the defrosting operation on the first cooling coil 51 side, the first opening/closing device 11 is closed to isolate the first outlet area 173 from the inside of the refrigerator, and the second opening/closing device 12 is opened to connect the first outlet area 173 to the mixing area 181. As a result, in the third operating state, air is sent to the first cooling coil 51 to which the drain water melted by the defrosting operation of the first cooling coil 51 is attached, causing the drain water to evaporate and generating high-humidity air, which returns to the mixing area 181 via the first return flow path 182. Then, in the mixing area 181, the air is mixed with the air inside the refrigerator sucked in by the second fan 20 to generate high-humidity cooled air, which allows the food inside the refrigerator to be cooled with high humidity.

Next, if ice formation on the first cooling coil is confirmed in the third operating state, the operating state is switched from the third operating state to the second operating state. Switching from the third operating state to the second operating state can be determined by fluctuations in the differential pressure using the static pressure sensors 81 to 84, as described above. Thereafter, the second operating state and the third operating state are alternately repeated.

As described above, the cooling device 2 according to the second embodiment has a mixing area 181 provided upstream of the first cooling coil 51 and the second cooling coil 61, in which the air taken in by the first fan 10 and the high humidity air generated by sending air to the second cooling coil 61 during defrosting operation are mixed, a first outlet area 173 provided downstream of the first cooling coil 51, a second outlet area 174 provided downstream of the second cooling coil 61, a first opening/closing device 11 provided in the first outlet area 173 and capable of switching between communication and blocking with the interior of the refrigerator, a second opening/closing device 12 provided in the first outlet area 173 and capable of switching between communication and blocking with the mixing area 181, a third opening/closing device 13 provided in the second outlet area 174 and capable of switching between communication and blocking with the interior of the refrigerator, and a fourth opening/closing device 14 provided in the second outlet area 174 and capable of switching between communication and blocking with the mixing area 181. With the cooling device 2 configured in this way, the load on the second cooling coil 61 side affects the first cooling coil 51 side, so the one-sided operation time until freezing occurs on the first cooling coil 51 side can be extended.

Third Embodiment
Next, the configuration of a cooling device 3 according to a third embodiment will be described with reference to FIGS. 4A and 4B.

Figures 4A and 4B are schematic diagrams showing a cooling device 3 according to a third embodiment of the present invention.

Explanations of parts common to the first embodiment will be omitted, and only features unique to the third embodiment will be explained. Note that the same members as those in the first embodiment described above will be denoted by the same reference numerals, and duplicate explanations will be omitted. The third embodiment differs from the first embodiment in the configuration of the housing, etc.

As shown in Figures 4A and 4B, the cooling device 3 according to the third embodiment has a first fan 10, a second fan 20, a first prefilter 30, a second prefilter 40, a first refrigeration cycle 50, a second refrigeration cycle 60, a first housing 270, a second housing 280, and a first static pressure sensor 81 to a fourth static pressure sensor 84. The first fan 10, the second fan 20, the first prefilter 30, the second prefilter 40, the first refrigeration cycle 50, the second refrigeration cycle 60, and the first static pressure sensor 81 to the fourth static pressure sensor 84 have the same configuration as the cooling device 1 according to the first embodiment described above, and therefore a description thereof will be omitted.

The first housing 270 is disposed inside the second housing 280. As shown in Figures 4A and 4B, the first housing 270 has a first region 271 in which the first fan 10, the first prefilter 30, and the first cooling coil 51 are disposed, and a second region 272 in which the second fan 20, the second prefilter 40, and the second cooling coil 61 are disposed.

In the first region 271 of the first housing 270, a first inlet region 273 is formed upstream of the first fan 10, and a first outlet region 274 is formed downstream of the first cooling coil 51. In the first inlet region 273, as shown in Figs. 4A and 4B, a first opening/closing device 21 capable of switching between communication and cut-off with the interior of the refrigerator and a second opening/closing device 22 capable of switching between communication and cut-off with the first outlet region 274 are arranged. In the first outlet region 274, as shown in Figs. 4A and 4B, a third opening/closing device 23 capable of switching between communication and cut-off with the interior of the refrigerator and a fourth opening/closing device 24 capable of switching between communication and cut-off with the first inlet region 273 are arranged.

In the second region 272 of the first housing 270, a second inlet region 275 is formed upstream of the second fan 20, and a second outlet region 276 is formed downstream of the second cooling coil 61. In the second inlet region 275, as shown in Figs. 4A and 4B, a fifth opening/closing device 25 capable of switching between communication and cut-off with the interior of the refrigerator and a sixth opening/closing device 26 capable of switching between communication and cut-off with the second outlet region 276 are arranged. In the second outlet region 276, as shown in Figs. 4A and 4B, a seventh opening/closing device 27 capable of switching between communication and cut-off with the interior of the refrigerator and an eighth opening/closing device 28 capable of switching between communication and cut-off with the second inlet region 275 are arranged.

The second housing 280 is formed to surround the first housing 270. As shown in Figures 4A and 4B, the second housing 280 has a first return flow passage 281 connecting the first inlet region 273 and the first outlet region 274, and a second return flow passage 282 connecting the second inlet region 275 and the second outlet region 276.

Next, the cooling method of the cooling device 3 according to the third embodiment will be described with reference to Figures 4A and 4B. Figure 4A is a diagram showing a state in which a cooling operation is performed on the first cooling coil 51 side and a defrosting operation is performed on the second cooling coil 61 side, and Figure 4B is a diagram showing a state in which a cooling operation is performed on the second cooling coil 61 side and a defrosting operation is performed on the first cooling coil 51 side.

First, in the first refrigeration cycle 50 and the second refrigeration cycle 60, the refrigerant is circulated to perform cooling operation inside the storage unit (first operating state). At that time, the set temperature inside the storage unit during cooling operation is set to 0°C or higher.

After the first operating state continues for a predetermined time, the first refrigeration cycle 50 stops operating, and the second refrigeration cycle 60 starts cooling operation. After that, when ice formation on the second cooling coil 61 is confirmed, as shown in FIG. 4A, cooling operation starts on the first cooling coil 51 side, and de-icing operation is performed on the second cooling coil 61 side (second operating state).

In cooling operation on the first cooling coil 51 side, the first evaporation pressure regulating valve 56 is controlled to maintain the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the first cooling coil 51, thereby minimizing the temperature difference ΔT between the surface temperature (evaporation temperature) of the first cooling coil 51 and the temperature of the air taken in (suction temperature). By reducing the temperature difference ΔT in this way, it is possible to effectively suppress dehumidification of the air inside the storage unit that accompanies cooling as it passes through the first cooling coil 51, and it is possible to maintain a high humidity level (e.g., 85% or higher).

In the cooling operation on the first cooling coil 51 side, as shown in FIG. 4A, the first opening/closing device 21 is opened to connect the first inlet area 273 to the inside of the refrigerator, and the second opening/closing device 22 is closed to isolate the first inlet area 273 from the first outlet area 274. The third opening/closing device 23 is opened to connect the first outlet area 274 to the inside of the refrigerator, and the fourth opening/closing device 24 is closed to isolate the first outlet area 274 from the first inlet area 273. As a result, the air that has entered the first inlet area 273 via the first opening/closing device 21 is cooled with high humidity in the first cooling coil 51, and then blown out from the first outlet area 274 via the third opening/closing device 23 into the refrigerator.

In the de-icing operation on the second cooling coil 61 side, the de-icing operation is performed without stopping the supply of refrigerant. Specifically, de-icing is performed in the second cooling coil 61 by operating the coil with the refrigerant evaporation temperature in the range of 0 to 3°C. In the de-icing operation, the second evaporation pressure adjustment valve 66 is controlled to increase the evaporation pressure in the second cooling coil 61, increasing the saturation temperature of the refrigerant, and de-icing the second cooling coil 61 by heating it from the inside.

In the defrosting operation on the second cooling coil 61 side, as shown in FIG. 4A, the fifth opening/closing device 25 is closed to isolate the second inlet area 275 from the inside of the refrigerator, and the sixth opening/closing device 26 is opened to connect the second inlet area 275 to the second outlet area 276. The seventh opening/closing device 27 is closed to isolate the second outlet area 276 from the inside of the refrigerator, and the eighth opening/closing device 28 is opened to connect the second outlet area 276 to the second inlet area 275. In this embodiment, the flow paths for the cooling operation and the defrosting operation are independent, and the flow path on the defrosting operation side is looped, so that all of the sensible heat of the fan can be used as a heat source for defrosting, and the defrosting operation can be performed without mixing in the cooling air generated by the cooling operation, which shortens the defrosting time.

Next, after the de-icing operation on the second cooling coil 61 side in the second operating state is completed, de-icing operation is performed on the first cooling coil 51 side, and cooling operation is performed on the second cooling coil 61 side (third operating state), as shown in FIG. 4B.

In cooling operation on the second cooling coil 61 side, the second evaporation pressure regulating valve 66 is controlled to maintain the evaporation temperature of the refrigerant at a temperature 0.1 to 3.0°C lower (e.g., -1.0°C) than the temperature of the air passing through the second cooling coil 61, thereby minimizing the temperature difference ΔT between the surface temperature (evaporation temperature) of the second cooling coil 61 and the temperature of the air taken in (suction temperature). By reducing the temperature difference ΔT in this way, it is possible to effectively suppress dehumidification of the air inside the storage unit that accompanies cooling as it passes through the second cooling coil 61, and it is possible to maintain a high humidity level (e.g., 85% or higher).

In the cooling operation on the second cooling coil 61 side, as shown in FIG. 4B, the fifth opening/closing device 25 is opened to connect the second inlet area 275 to the inside of the refrigerator, and the sixth opening/closing device 26 is closed to isolate the second inlet area 275 from the second outlet area 276. The seventh opening/closing device 27 is opened to connect the second outlet area 276 to the inside of the refrigerator, and the eighth opening/closing device 28 is closed to isolate the second outlet area 276 from the second inlet area 275. As a result, the air that has entered the second inlet area 275 via the fifth opening/closing device 25 is cooled in the second cooling coil 61, and then blown out from the second outlet area 276 into the refrigerator via the seventh opening/closing device 27.

In the de-icing operation on the first cooling coil 51 side, the de-icing operation is performed without stopping the supply of refrigerant. Specifically, de-icing is performed in the first cooling coil 51 by operating the refrigerant at an evaporation temperature in the range of 0 to 3°C. In the de-icing operation, the first evaporation pressure regulating valve 56 is controlled to increase the evaporation pressure in the first cooling coil 51, increasing the saturation temperature of the refrigerant, and de-icing the first cooling coil 51 by heating it from the inside.

In the defrosting operation on the first cooling coil 51 side, as shown in FIG. 4B, the first opening/closing device 21 is closed to isolate the first inlet area 273 from the inside of the refrigerator, and the second opening/closing device 22 is opened to connect the first inlet area 273 to the first outlet area 274. The third opening/closing device 23 is closed to isolate the first outlet area 274 from the inside of the refrigerator, and the fourth opening/closing device 24 is opened to connect the first outlet area 274 to the first inlet area 273. As a result, in the third operating state, air is sent to the first cooling coil 51 to which the drain water melted by the defrosting operation on the first cooling coil 51 is attached, and the drain water evaporates to generate high humidity air, which returns to the first inlet area 273 via the first return flow path 281.

Next, if ice formation on the first cooling coil is confirmed in the third operating state, the operating state is switched from the third operating state to the second operating state. Switching from the third operating state to the second operating state can be determined by fluctuations in the differential pressure using the static pressure sensors 81 to 84, as described above. Thereafter, the second operating state and the third operating state are alternately repeated.

As described above, the cooling device 3 according to the third embodiment includes a first inlet region 273 provided upstream of the first cooling coil 51, a second inlet region 275 provided upstream of the second cooling coil 61, a first outlet region 274 provided downstream of the first cooling coil 51, a second outlet region 276 provided downstream of the second cooling coil 61, a first opening/closing device 21 provided in the first inlet region 273 and capable of switching between communication and blocking with the interior of the storage unit, a second opening/closing device 22 provided in the first inlet region 273 and capable of switching between communication and blocking with the first outlet region 274, and a second opening/closing device 23 provided in the first outlet region 274 and capable of switching between communication and blocking with the interior of the storage unit. The cooling device 3 has a third opening/closing device 23 that can be switched between open and closed, a fourth opening/closing device 24 that is provided in the first outlet area 274 and can be switched between open and closed with the first inlet area 273, a fifth opening/closing device 25 that is provided in the second inlet area 275 and can be switched between open and closed with the interior of the refrigerator, a sixth opening/closing device 26 that is provided in the second inlet area 275 and can be switched between open and closed with the second outlet area 276, a seventh opening/closing device 27 that is provided in the second outlet area 276 and can be switched between open and closed with the interior of the refrigerator, and an eighth opening/closing device 28 that is provided in the second outlet area 276 and can be switched between open and closed with the second inlet area 275. The cooling device 3 configured in this way can shorten the defrosting time.

The configuration of the cooling device has been described above through the embodiments, but the present invention is not limited to the above-mentioned embodiments and can be modified in various ways within the scope of the claims.

For example, in the above embodiment, switching from the second operating state to the third operating state was performed by measuring the differential pressure, but it may also be performed by measuring the temperature with a thermometer, measuring the time with a timer, taking a picture with a camera, etc. These methods make it easy to switch operating states, and one cooling coil can continue to perform cooling operation while the other cooling coil is in de-icing operation, so that high-humidity cooled air can be continuously supplied to the interior of the storage unit.

In the above-described embodiment, the de-icing operation is performed without stopping the supply of refrigerant, and the evaporation pressure control valve is controlled to increase the evaporation pressure in the cooling coil, thereby increasing the saturation temperature of the refrigerant and warming the cooling coil from the inside to de-icing. However, the de-icing operation may also be performed in the off-cycle by using the sensible heat of the first fan 10 or the second fan 20 as a heat source.

In addition, in the above-described embodiment, the cooling device 1 has a first fan 10 and a second fan 20, but a single fan may be used to take in the air from inside the cabinet after cooling the food to a high humidity level, and blow it toward the first cooling coil 51 and the second cooling coil 61.

In the above-described embodiment, the first cooling coil 51 and the second cooling coil 61 are microchannel heat exchangers. However, the first cooling coil and the second cooling coil may be plate fin coils.

In addition, in the above embodiment, two refrigeration cycles are provided, but three or more may be provided.

In addition, in the above-mentioned embodiment, a direct expansion type cooling device is used, but an indirect expansion type may also be used.

In addition, in the above-described embodiment, the first cooling coil 51 and the second cooling coil 61 are arranged so as to be inclined with respect to the vertical direction, but the first cooling coil 51 and the second cooling coil 61 may be arranged in the horizontal direction as shown in FIG. 6. With this configuration, the water adhering to and retained on the fins of the microchannel heat exchanger can be more effectively caused to fall downward by gravity, so that freezing on the first cooling coil 51 and the second cooling coil 61 can be more effectively prevented when performing the cooling operation after the de-icing operation is completed.

In addition, in the above-described embodiment, a damper valve is used as the opening and closing device, but a shutter may also be used.

1, 2, 3 Cooling device,
10. First fan,
11, 21 First opening/closing device,
12, 22 Second opening/closing device,
13, 23 Third opening/closing device,
14, 24 Fourth opening and closing device,
25 Fifth opening and closing device,
26 sixth opening and closing device,
27 Seventh opening and closing device,
28 8th opening and closing device,
20. Second fan,
51 first cooling coil,
61 second cooling coil,
73 Mixed region,
173 first exit area,
174 second exit area;
181 mixed region,
273 first inlet region,
274 first exit area,
275 second inlet region;
276 Second exit area.

Claims (9)

A cooling device that cools food in a storage compartment at a negative temperature and high humidity,
A plurality of cooling coils for cooling the air inside the storage compartment by a refrigerant circulating through the cooling device;
a plurality of fans that take in the air inside the storage compartment after cooling the food to a high humidity level and blow it toward the plurality of cooling coils. The cooling device of claim 1, wherein the cooling coil is a microchannel heat exchanger. The cooling device according to claim 2, wherein the microchannel heat exchanger is disposed at an angle relative to the vertical direction. The cooling device according to claim 3, wherein the angle at which the microchannel heat exchanger is inclined relative to the vertical direction is between 45 and 90 degrees. The cooling device according to claim 1 or 2, wherein the fan is a centrifugal fan. The cooling device according to claim 1 or 2, further comprising a mixing area provided downstream of the cooling coils, in which air passing through one of the cooling coils during cooling operation and air passing through the other cooling coil during defrosting operation are mixed to generate high humidity cooling air. A mixing zone is provided upstream of the cooling coil, in which the air taken in by one of the fans and the high humidity air generated by sending air to the cooling coil during defrosting operation are mixed;
a first outlet region provided downstream of one of the cooling coils;
a second outlet region downstream of the other cooling coil;
A first opening/closing device provided in the first outlet area and capable of switching communication/cut-off with the interior of the container;
A second opening/closing device provided in the first outlet area and capable of switching communication/cut-off with the mixing area;
A third opening/closing device provided in the second outlet area and capable of switching communication/cut-off with the interior of the container;
The cooling device according to claim 1 or 2, further comprising: a fourth opening and closing device provided in the second outlet region and capable of switching between communication with the mixing region and being cut off. a first inlet region provided upstream of one of the cooling coils;
a second inlet region provided upstream of the other cooling coil;
a first outlet region provided downstream of one of the cooling coils;
a second outlet region downstream of the other cooling coil;
A first opening/closing device provided in the first inlet area and capable of switching communication/cut-off with the interior of the container;
a second opening/closing device provided in the first inlet area and capable of switching between communication and cut-off with the first outlet area;
A third opening/closing device provided in the first outlet area and capable of switching communication/cut-off with the interior of the container;
a fourth opening/closing device provided in the first outlet area and capable of switching between communication with the first inlet area and disconnection;
A fifth opening/closing device provided in the second inlet area and capable of switching communication/cut-off with the interior of the container;
a sixth opening/closing device provided in the second inlet area and capable of switching between communication and cut-off with the second outlet area;
A seventh opening/closing device provided in the second outlet area and capable of switching communication/cut-off with the interior of the container;
The cooling device according to claim 1 or 2, further comprising: an eighth opening/closing device provided in the second outlet area and capable of switching between communication and cut-off with the second inlet area. A cooling method for cooling food in a refrigerator at a negative temperature and high humidity, comprising:
A cooling method in which a refrigeration cycle has a plurality of cooling coils for cooling air circulating inside the storage compartment by a refrigerant circulating through a cooling device, in which a cooling operation is performed in one of the cooling coils and a de-icing operation is performed in the other cooling coil.