Food storage

Abstract

To provide a storage warehouse or a storage room capable of drying food with one simple cooling device even when a dehumidification amount is increased due to an increase in food to be dried.SOLUTION: A storage warehouse or a storage room comprises: a storage compartment to store food; a cooling section to cool the storage compartment; a defrosting section to melt frost attached to the cooling section; a temperature detection section to detect an inner temperature of the storage compartment; and a control section which controls the inner temperature of the storage compartment. In the storage warehouse or the storage room, a drying process to increase the inner temperature of the storage compartment in stages has: a drying process to keep a temperature inside the storage compartment in a first temperature range less than 0°C for a predetermined period; and a drying process to keep the temperature inside the storage compartment in a second temperature range equal to or higher than 0°C for a predetermined period. The number of times of defrosting operation to melt the frost attached to the cooling section executed by the defrosting section in the first temperature range is controlled to be larger than the same in the second temperature range. Thus, the storage warehouse or the storage room enhances drying of food inside the storage compartment regardless of an amount of the food and thereby producing dried food which has healthy colors, good external appearances and enables a consumer to realize tastes close to fresh food.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a storage or storage room in which food drying is carried out.

Background Art

[0002] Conventionally, in a storage or storage room in which food drying is carried out, in the case of having a cooler in the cooling section, when the amount of food to be dried increases and the dehumidification amount increases, frosting occurs on the cooler, and the dehumidification performance deteriorates. Therefore, there are those that have two coolers and perform defrosting to melt the frosted frost while the other is performing dehumidification, and alternately and independently perform dehumidification and defrosting operations (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-mentioned conventional storage or storage room, having two coolers makes it large-scale and the system also becomes complicated. In addition, the device itself becomes more expensive, and it becomes impossible to dry food easily or inexpensively. There is also room for improvement regarding the nutritional components, functional components contained in the food, and the "tastiness" of the dried food.

Means for Solving the Problems

[0005] In order to solve the above-mentioned conventional problems, the storage of the present invention The storage, a storage compartment for storing food, a cooling unit for cooling the storage compartment, a defrosting unit for melting the frost adhering to the cooling unit, a temperature detection unit for detecting the internal temperature of the storage compartment, and a control unit for controlling the internal temperature of the storage compartment. By providing these components, the cooler can be used in a simple device with a single unit to perform drying. As a drying process for gradually increasing the internal temperature of the storage compartment, there are a drying process of maintaining the temperature within a first temperature range below 0°C for a predetermined time and a drying process of maintaining the internal temperature of the storage compartment within a second temperature range of 0°C or higher for a predetermined time. The first temperature zone includes a freezing temperature zone of -18°C or lower. In the first temperature zone, defrosting to melt the frost on the cooling part performed by the defrosting part is carried out at predetermined intervals. When switching from the first temperature zone to the second temperature zone, defrosting is started. In the second temperature zone, no defrosting is performed As a result, drying can be completed more efficiently in a shorter time, and it is possible to obtain dried food that can provide a sense of "tastiness" while retaining as much as possible the nutrients and functional components contained in the food.

Advantages of the Invention

[0006] In the refrigerator or storage room of the present invention, there are provided a storage compartment for storing food, a cooling unit for cooling the storage compartment, a defrosting unit for melting the frost adhering to the cooling unit, a temperature detection unit for detecting the internal temperature of the storage compartment, and a control unit for controlling the internal temperature of the storage compartment. As a drying process for gradually increasing the internal temperature of the storage compartment, there are a drying process of maintaining the temperature within a first temperature range below 0°C for a predetermined time and a drying process of maintaining the internal temperature of the storage compartment within a second temperature range of 0°C or higher for a predetermined time. In the first temperature range, by controlling the number of defrosting operations for melting the frost on the cooling unit performed by the defrosting unit to be more than that in the second temperature range, drying is performed while maintaining the temperature from the freezing range for a predetermined time. Therefore, drying can be performed in an environment where the growth of spoilage bacteria is suppressed. In the drying process, drying can proceed easily with a single cooler, and by efficiently defrosting the frost that forms, drying is promoted, and drying is completed in a short time. Drying can proceed without the growth of spoilage bacteria and while suppressing the reactivity of chemical reactions.

Brief Description of the Drawings

[0007]

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[0008] The first invention includes a storage section for storing food, a cooling section for cooling the storage section, a defrosting section for melting the frost adhering to the cooling section, a temperature detection section for detecting the internal temperature of the storage section, and a control section for controlling the internal temperature of the storage section. As a drying process for gradually increasing the internal temperature of the storage section, it has a drying process of maintaining for a predetermined time in a temperature range below 0°C which is the first temperature zone, and a drying process of maintaining for a predetermined time in a temperature range of 0°C or higher which is the second temperature zone. In the first temperature zone, the number of defrosting times for melting the frost on the cooling section performed by the defrosting section is controlled to be more than that in the second temperature zone. By using a refrigerator or storage room characterized in this way, it is possible to easily dry food with a single cooler device. By improving the efficiency of defrosting, drying can be completed in a shorter time, the nutritional and functional components contained in the food are retained, and it is possible to obtain dried food that can also give a sense of "tastiness". Also, even if the weight of the food to be dried increases, it can be easily dried regardless of the amount.

[0009] The second invention includes a cooler temperature detection unit that detects the temperature of the cooling unit. The defrosting unit is the refrigerator or storage room according to claim 1, and starts defrosting when the rate of decrease in the temperature detected by the cooler temperature detection unit increases. By predicting an increase in frosting on the cooler from the rate of decrease in the cooler temperature and performing defrosting, defrosting can be controlled more accurately.

[0010] The third invention includes an air temperature detection unit that detects the temperature on the downwind side of the cooling unit. The defrosting unit is the refrigerator or storage room according to claim 1, and starts defrosting when the temperature detected by the air temperature detection unit rises. By predicting an increase in frosting on the cooler from the temperature rise and performing defrosting, defrosting can be controlled more accurately.

[0011] The fourth invention includes an air humidity detection unit that detects the humidity on the downwind side of the cooling unit. The defrosting unit is the refrigerator or storage room according to claim 1, and starts defrosting when the humidity detected by the air humidity detection unit rises. By predicting an increase in frosting on the cooler from the humidity rise and performing defrosting, defrosting can be controlled more accurately.

[0012] The fifth invention is the refrigerator or storage room according to any one of claims 1 to 4, which includes a discharge port that discharges the moisture generated when the frost adhering to the cooling unit melts to the outside of the storage compartment, and an opening and closing means that opens and closes the discharge port. By doing so, it is possible to suppress an increase in humidity in the storage compartment due to defrosting moisture, and drying can be performed in a shorter time.

[0013] The sixth invention includes a storage compartment for storing food, a cooling unit for cooling the storage compartment, a blower for circulating the air cooled by the cooling unit to the storage compartment, a temperature detection unit for detecting the internal temperature of the storage compartment, and a control unit for controlling the cooling unit using the information from the temperature detection unit to control the internal temperature of the storage compartment. As a drying process for gradually raising the internal temperature of the storage compartment, there is a drying process of maintaining for a predetermined time in a temperature range below 0°C which is the first temperature zone, and a drying process of maintaining for a predetermined time in a temperature range of 0°C or higher which is the second temperature zone. By providing a dehumidifying unit for dehumidifying the passing air upstream of the cooling unit in a storage or storage room, drying can be performed in a shorter time without defrosting the cooler.

[0014] The seventh invention is the storage or storage room according to claim 6, characterized in that the dehumidifying unit is a desiccant type dehumidifying means. Since it can dehumidify regardless of temperature, it can exhibit effects in a wide temperature range and drying can be performed in a shorter time.

[0015] The eighth invention is the storage or storage room according to claim 6, characterized in that the dehumidifying unit is a moisture permeable membrane type total heat exchanger. Since dehumidification can be performed with a simple configuration, drying can be performed more easily.

[0016] The ninth invention is the storage or storage room according to claim 6, characterized in that the dehumidifying unit is a small cooler. Since it has excellent dehumidifying ability at high temperatures, drying can be performed in a shorter time.

[0017] (Embodiment 1) FIG. 1 is a cross-sectional view of the drying storage 1 of the present Embodiment 1.

[0018] In Figure 1, the dry storage cabinet 1 is partitioned vertically by a heat-insulating partition wall 2. Inside the dry storage cabinet 1, there is a dry storage chamber (storage compartment) 3 arranged above the heat-insulating partition wall 2 and a freezer compartment 4 arranged below the heat-insulating partition wall 2. Also, inside the dry storage cabinet 1, a control unit 5 for driving and controlling each part and device of the dry storage cabinet 1 is arranged.

[0019] The refrigeration cycle 6 is formed by connecting a compressor 7, a radiator 8, an expansion means 9, and a cooler 10 in a loop, and a refrigerant such as isobutane is enclosed therein. The cooler 10 is located at the back of the freezer compartment 4.

[0020] The compressor 7 can increase or decrease its capacity by changing the rotational speed of the motor, for example, by an inverter power supply, and its capacity is controlled by the control unit 5.

[0021] Similarly, at the back of the freezer compartment 4, a blower 11 for forcibly ventilating the cold air generated by the cooler into the dry storage chamber 3 is arranged, and a dry chamber duct 12 for guiding the cold air into the dry storage chamber 3 is provided.

[0022] Inside the dry chamber duct 12, there are a damper 13 for selectively flowing the cold air into the dry storage chamber 3 and a dry chamber heater 14 for heating the cold air in the dry chamber duct 12, which is composed of, for example, fins and a pipe heater.

[0023] Also, inside the dry storage chamber 3, an air temperature and humidity detection unit 15 for detecting the internal temperature and humidity of the dry storage chamber 3 is provided.

[0024] Also, when frost adheres to the cooler 10, a defrosting unit 16 for melting the frost is provided.

[0025] Also, an operation panel 17 is arranged on the dry storage cabinet 1. The control unit 5 performs drive control of each part and device according to the instructions of the user input via the operation panel 17.

[0026] The operation of the drying storage cabinet 1 configured as described above will be described below. During the operation of the refrigeration cycle 6, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 7 dissipates heat to the outside air as it flows through the radiator 8, becoming a low-temperature and high-pressure liquid refrigerant. Then, as it flows through the expansion means 9 such as a capillary tube, it becomes a low-temperature and low-pressure gas-liquid two-layer refrigerant and flows into the cooler 10.

[0027] The liquid refrigerant flowing through the cooler 10 exchanges heat with the air in the freezer compartment 4, generates cold air by the latent heat of evaporation, and is circulated through the freezer compartment 4 and the drying storage compartment 3 by the blower 11. By this action, the freezer compartment 4 is cooled and maintained in a refrigeration temperature range of about -18°C or lower.

[0028] The drying storage compartment 3 is normally maintained in a temperature range of -18°C or lower. This refrigeration temperature of -18°C is set based on the concept of T-TT (Time-Temperature-Tolerance: storage period - storage temperature and quality tolerance). In T-TT, it is said that the time for maintaining the freshness of food and the time for maintaining the quality of food (from the viewpoints of microorganisms and taste) are different.

[0029] The drying storage compartment 3 is normally maintained in a refrigeration temperature range of about -18°C or lower. However, when the user puts food in and starts the drying operation mode in response to the user's instruction input via the operation panel 17, the control unit 5 controls the compressor 7, the blower 11, the damper 13, and the drying chamber heater 14 according to the temperature detected by the air temperature and humidity detection unit 15, so that the air volume and temperature of the air flowing into the drying storage compartment 3 are controlled to be in a predetermined pattern.

[0030] Here, taking the case of storing in the drying storage compartment 3 as an example, the drying process of the storage cabinet in the first embodiment will be described.

[0031] First, place the tomatoes cut in half in the drying storage compartment 3, operate the switch on the operation panel 17 to select "Drying Course 1", and further input the information of the tomatoes to be placed (such as size, thickness, weight, etc.) using the food information input means (17a) on the operation panel 17, and then operate it.

[0032] FIG. 2 is a diagram showing the temperature and defrosting pattern of the first embodiment. FIG. 3 is a diagram showing the mechanism by which the food in the first embodiment dries.

[0033] In FIG. 3, the air flow is indicated by arrows. First, the saturated air flowing out from the cooler is heated by the drying chamber heater, so that the relative humidity decreases and it becomes dry air and enters the storage section by the cooling fan. By this dry air, the moisture of the food installed in the storage section sublimates and evaporates into the air, becomes moist air, and returns to the cooler again. This series of cycles is repeated and drying progresses.

[0034] On the other hand, as drying progresses, frost gradually forms on the cooler due to the moist air. This frosting hinders the air flow in the cooler and makes heat exchange in the cooler difficult, making it difficult to lower the temperature and humidity of the circulating air and resulting in a decrease in the drying efficiency of the food.

[0035] In the drying example without defrosting in FIG. 4, the temperature, humidity, cooler temperature, and weight of the food in the drying storage chamber are shown when drying tomatoes of the same lot as in the first embodiment in the same form (for example, size, thickness, weight, etc.) in the same storage as in the first embodiment without performing any defrosting.

[0036] If no defrosting is performed from the start of drying, the cooler will be clogged by the frost adhering to it, the cooler temperature will continue to drop, and eventually the humidity in the drying storage chamber will rise to 100%, the weight of the food will not decrease, and the drying of the food will not progress. (FIG. 4) Therefore, defrosting is always necessary as drying progresses.

[0037] Using FIG. 2, the operations of each device during the drying operation of the first embodiment, the changes in various temperatures and humidities in the drying storage, and the defrosting timing will be described.

[0038] When the drying operation is started, in the first temperature zone, the control unit 5 maintains the internal temperature of the drying storage chamber 3 in the refrigeration temperature zone of -18°C or lower (for example, -25°C as an example). For example, the compressor 7 and the blower 11 are operated at maximum capacity, the damper 13 is fully opened, and the drying chamber heater 14 is not energized, thereby stabilizing the refrigeration temperature zone (for example, -25°C).

[0039] When a predetermined time has elapsed (for example, 480 minutes as an example), for example, by energizing the drying chamber heater 14, in order to lower the internal humidity of the drying storage chamber 3, the internal temperature is raised (for example, -3°C), and the control unit 5 controls each device to maintain the temperature, and appropriate defrosting is performed. In the first temperature zone, the humidity drops from 50% to 20%.

[0040] In the first temperature zone in the first embodiment, the defrosting timing is performed every predetermined time (for example, every two days as an example).

[0041] When a predetermined time has elapsed in the first temperature zone (for example, 7800 minutes as an example), the operation shifts to the second temperature zone, and the internal temperature of the drying storage chamber 3 rises (for example, 3°C), and the control unit 5 controls each device to maintain that temperature.

[0042] When a predetermined time has elapsed (for example, 120 minutes as an example), for example, by energizing the drying chamber heater 14, in order to lower the internal humidity of the drying storage chamber 3, the internal temperature further rises (for example, 8°C), and the control unit 5 controls each device so that the humidity drops to 8% in the second temperature zone.

[0043] The reduction of moisture from the food is less in the second temperature zone than in the first temperature zone. Therefore, defrosting is not performed, the drying operation ends in a predetermined time (for example, 6000 minutes as an example), and dried tomatoes are completed in about 10 days.

[0044] As shown in Fig. 5, in the same storage as in Embodiment 1, using tomatoes of the same lot and the same form (e.g., size, thickness, weight, etc.) with the same temperature pattern in the same drying chamber, the humidity in the drying and storage chamber and the weight of the food when defrosting is performed every day are shown.

[0045] In Fig. 5, defrosting is performed every day. By performing defrosting, the frost adhering to the cooler melts, the weight gradually decreases, and drying progresses. However, with each defrosting, the air is humidified, the humidity increases, and as a result, the drying efficiency decreases, and it takes 14 days to complete drying.

[0046] In Embodiment 1, defrosting is performed every predetermined time (2 days as an example) in the first temperature zone. Thereby, while moderately suppressing frosting on the cooler, by also suppressing the increase in humidity in the drying and storage chamber, drying progresses efficiently, and the drying time can be shortened to 10 days.

[0047] Also, as shown in Fig. 3, when provided with a cooler temperature detection unit for detecting the temperature of the cooler, as shown in Fig. 6, when the temperature decrease width △T1 per 30 minutes of the cooler temperature increases like △T2, that is, at the timing when the decrease rate of the cooler temperature increases, the defrosting unit starts defrosting, so that defrosting can be controlled more accurately, drying is made more efficient, and the drying time is shortened.

[0048] Also, as shown in Fig. 3, when provided with an air temperature detection unit for detecting the temperature on the leeward side of the cooler, as shown in Fig. 7, by starting defrosting at the timing when the air temperature downstream of the cooler rises by 1K or more in 30 minutes, defrosting can be controlled accurately, drying is made more efficient, and the drying time is shortened.

[0049] Also, as shown in Fig. 3, when provided with an air humidity detection unit for detecting the humidity on the leeward side of the cooler, as shown in Fig. 8, by starting defrosting at the timing when the air humidity downstream of the cooler rises by 1% or more in 30 minutes, defrosting can be controlled accurately, drying is made more efficient, and the drying time is shortened.

[0050] Also, as shown in Fig. 3, when the opening and closing means is provided, after defrosting, the opening and closing means is opened, and the high-temperature and high-humidity air generated by defrosting can be discharged from the discharge port to the outside of the drying storage. Thereby, an increase in humidity in the storage section after the defrosting operation can be suppressed, drying is made more efficient, and the drying time is shortened.

[0051] Fig. 9 shows the sensory evaluation results of tomatoes dried by the above-described method. As a conventional example, tomatoes dried by osmotic dehydration with normal-temperature sugar of the same lot as that of the first embodiment were used.

[0052] As shown in Fig. 9, compared with the conventional example, the halved tomatoes of the first embodiment increased by 1 point or more in the items "Appearance (large or small discoloration)", "Fragrance (strong or weak)", and "Overall (good or bad)", had less discoloration, had a strong fresh raw fragrance, and overall had a better taste.

[0053] Since a difference of 1 point in the sensory evaluation is clearly recognized, the halved tomatoes dried with the temperature pattern of the first embodiment can realize a level at which the difference in "tastiness" can be felt in a shorter time compared with the conventional example after drying and storage.

[0054] In the first embodiment, by appropriately performing defrosting, drying is completed efficiently in a short time. Therefore, compared with tomatoes dried by osmotic dehydration with normal-temperature sugar, denaturation is suppressed, the "appearance" and "fragrance" before storage are maintained, there is less discoloration, the fragrance becomes stronger, and a healthy dried product without the addition of sugar can be obtained.

[0055] Also, in the first embodiment, since drying in a temperature range of 0°C or lower is used, compared with tomatoes dried by osmotic dehydration with sugar at normal temperature in the vicinity of 20 to 30°C above 0°C, it is also expected that the loss of nutrient components that are denatured by oxidation such as vitamin C and total polyphenols is small.

[0056] In Embodiment 1, in the first temperature zone, after a predetermined time (e.g., 480 minutes) has elapsed in the freezing temperature zone (e.g., -25°C), the internal temperature of the storage compartment rises (e.g., -3°C), and the humidity drops from 50% to 20%.

[0057] In the first temperature zone, defrosting is performed every predetermined time (e.g., 2 days).

[0058] Thereafter, it is maintained for a predetermined time (e.g., 7800 minutes), then shifted to the second temperature zone. When the internal temperature rises (e.g., 3°C) and a predetermined time (e.g., 120 minutes) elapses, the internal temperature further rises (e.g., 8°C). In the second temperature zone, the humidity drops to 8%.

[0059] In the second temperature zone, defrosting is not performed, and the drying operation ends in a predetermined time (e.g., 6000 minutes), and dried tomatoes are completed in about 10 days.

[0060] As is clear from the above description, the storage or storage room of Embodiment 1 includes a storage compartment for storing food, a cooling unit for cooling the storage compartment, a defrosting unit for melting the frost adhering to the cooling unit, a temperature detection unit for detecting the internal temperature of the storage compartment, and a control unit for controlling the internal temperature of the storage compartment. As a drying process for gradually raising the internal temperature of the storage compartment, there are a drying process of maintaining for a predetermined time in a temperature range below 0°C which is the first temperature zone, and a drying process of maintaining for a predetermined time in a temperature range of 0°C or more which is the second temperature zone of the internal temperature of the storage compartment. By controlling the number of defrosting times for melting the frost of the cooling unit performed by the defrosting unit in the first temperature zone to be more than that in the second temperature zone, regardless of the amount of food, the drying of the food installed in the storage compartment is promoted, and the dried tomatoes after drying have less discoloration, are brightly colored, have a good appearance, have a strong fresh raw aroma, have a natural sweetness close to raw, and a dried product with a "deliciousness" that can be felt can be obtained.

[0061] (Embodiment 2) FIG. 10 is a front view of the storage of Embodiment 2. In Embodiment 2, a dehumidifying unit is provided upstream of the cooler.

[0062] For other content that overlaps with the content described in Embodiment 1, the description will be omitted.

[0063] Also, FIG. 11 is a diagram showing the mechanism by which the food of the second embodiment dries.

[0064] In FIG. 11, the flow of air is indicated by arrows. First, the saturated air flowing out from the cooler is heated by the drying chamber heater, so that the relative humidity decreases and it becomes dry air and enters the storage section by the cooling fan. Due to this dry air, moisture sublimates and evaporates from the food placed in the storage section into the air, becoming moist air. This moist air is dehumidified by the dehumidifying section upstream of the cooler, upwind, on the way back to the cooler and returns to the cooler. This series of cycles is repeated and drying progresses.

[0065] In the second embodiment, since the dehumidified air flows into the cooler, defrosting during drying becomes unnecessary, and drying can be carried out more efficiently.

[0066] Also, the drying time can be further shortened, and the quality of the dried product is improved so that a better taste can be felt.

[0067] Also, by making the dehumidifying section a desiccant type, dehumidification can be performed regardless of the temperature, so that the effect can be exhibited in a wide temperature range and drying can be performed in a shorter time.

[0068] Also, by making the dehumidifying section a moisture permeable membrane type total heat exchanger, dehumidification can be performed with a simple configuration, and drying can be performed more easily.

[0069] Also, by making the dehumidifying section a small cooler, it has excellent dehumidifying ability at high temperatures, and drying can be performed in a shorter time.

[0070] As is apparent from the above, the storage or storage room of the second embodiment includes a storage section for storing food, a cooling section for cooling the storage section, a blower for circulating the air cooled by the cooling section to the storage section, a temperature detection section for detecting the internal temperature of the storage section, and a control section for controlling the cooling section using the information from the temperature detection section to control the internal temperature of the storage section. As a drying process for gradually increasing the internal temperature of the storage section, it has a drying process of maintaining for a predetermined time in a temperature range below 0°C, which is the first temperature zone, and a drying process of maintaining the internal temperature of the storage section for a predetermined time in a temperature range of 0°C or higher, which is the second temperature zone. By providing a dehumidifying section for dehumidifying the air passing above the cooling section, regardless of the amount of food, the drying of the food installed in the storage section is promoted. After drying, a dried product with less discoloration, vivid color, good appearance, a strong fresh raw aroma, a natural sweetness close to raw, and a sense of "deliciousness" can be obtained.

Industrial Applicability

[0071] As described above, since the refrigerator or storage room according to the present invention can appropriately control the temperature and humidity during storage, it can also be applied to uses for controlling and storing chemical reactions by changing the storage temperature and maintenance time of organic substances other than food.

Explanation of Reference Numerals

[0072] 1 Drying refrigerator 2 Heat insulation partition wall 3 Drying storage room (storage section) 4 Freezer 5 Control section 6 Refrigeration cycle 7 Compressor 8 Radiator 9 Expansion means 10 Cooler 11 Blower 12 Drying room duct 13 Damper 14 Drying room heater 15 Air temperature and humidity detection section 16 Defrosting section 17 Operation panel (17a)

Claims

1. A storage compartment for storing food, a cooling unit for cooling the storage compartment, a defrosting unit for melting frost adhering to the cooling unit, a temperature detection unit for detecting the internal temperature of the storage compartment, and a control unit for controlling the internal temperature of the storage compartment, As a drying process for gradually increasing the internal temperature of the storage compartment, a drying process of maintaining for a predetermined time in a temperature range below 0°C which is the first temperature zone, It has a drying process of maintaining for a predetermined time in a temperature range of 0°C or higher which is the second temperature zone of the internal temperature of the storage compartment, The first temperature zone includes a freezing temperature zone of -18°C or lower, In the first temperature zone, defrosting for melting the frost on the cooling unit performed by the defrosting unit is carried out at predetermined time intervals, When switching from the first temperature zone to the second temperature zone, the defrosting is started, A refrigerator characterized in that defrosting is not performed in the second temperature zone.

2. Comprising a cooler temperature detection unit for detecting the temperature of the cooling unit, and the defrosting unit starts defrosting when the rate of decrease in the temperature detected by the cooler temperature detection unit increases. The refrigerator according to Claim 1.

3. Comprising an air temperature detection unit for detecting the temperature on the downstream side of the wind of the cooling unit, and the defrosting unit starts defrosting when the temperature detected by the air temperature detection unit rises. The refrigerator according to Claim 1.

4. Comprising an air humidity detection unit for detecting the humidity on the downstream side of the wind of the cooling unit, and the defrosting unit starts defrosting when the humidity detected by the air humidity detection unit rises. The refrigerator according to Claim 1.

5. A refrigerator according to any one of Claims 1 to 4, comprising an exhaust port for discharging the warm and humid air generated when melting the frost adhering to the cooling unit to the outside of the storage compartment, and an opening and closing means for opening and closing the exhaust port.

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