JP7663025B2 - Cooling system - Google Patents

Description

This invention relates to a cooling device, and in particular to a cooling device that is configured to switch between cooling operation and defrosting operation of an evaporator.

Conventionally, there is known a freezer/refrigerator showcase (cooling device) that is configured so that the evaporator can be switched between cooling and defrosting operation (see, for example, Patent Document 1).

The above-mentioned Patent Document 1 discloses a cooling device that has multiple evaporators and can switch between cooling operation and defrosting operation of the multiple evaporators. The cooling device described in the above-mentioned Patent Document 1 is configured to cool the interior of the storage unit using the evaporators and remove frost from the evaporators (defrost) in parallel by alternately switching between cooling operation and defrosting operation of the multiple evaporators.

JP 2017-89901 A

However, in a cooling device such as that described in Patent Document 1, the cooling operation and defrosting operation of the multiple evaporators are alternately switched to allow the evaporators to cool the interior of the cabinet and remove frost from the evaporators (defrosting) in parallel. Therefore, when defrosting an evaporator, it is necessary to cool the air (cooling operation) to maintain the temperature inside the cabinet only with the evaporators that are not performing defrosting operation. Therefore, in a cooling device such as that described in Patent Document 1, if the amount of heat (heat load) required to maintain the cooling temperature inside the cabinet when defrosting the evaporators is large, the evaporators that are not performing defrosting operation alone will not be able to provide sufficient cooling, and the temperature inside the cabinet will not be easily maintained. In other words, if the heat load when defrosting the evaporators increases, there is a problem that it is not easy to maintain the temperature inside the cabinet.

This invention was made to solve the above problems, and one of the objectives of this invention is to provide a cooling device that can easily maintain the temperature inside the cabinet by suppressing the increase in heat load when defrosting the evaporator.

In order to achieve the above object, a cooling device according to one aspect of the present invention includes a compressor that compresses a refrigerant, a condenser that condenses the refrigerant discharged from the compressor, a main evaporator and a sub-evaporator that evaporate the refrigerant condensed by the condenser, a first air flow path in which the main evaporator is provided, and a second air flow path in which the sub-evaporator is provided and which is provided separately from the first air flow path, the cooling device is configured to switch between a cooling operation and a defrosting operation of the main evaporator, and during cooling operation of the main evaporator provided in the first air flow path, the cooling device is configured to cool a cooling space in which goods are stored in a state in which the temperature of the refrigerant flowing through the sub-evaporator provided in the second air flow path is set higher than the temperature of the refrigerant flowing through the main evaporator and a temperature at which frost forms on the sub-evaporator, and further includes a mixing region that mixes air flowing out of the first air flow path and air flowing out of the second air flow path .

In the cooling device according to the above aspect, as described above, during the cooling operation of the main evaporator provided in the first air flow path, the temperature of the refrigerant flowing through the sub-evaporator provided in the second air flow path is set higher than the temperature of the refrigerant flowing through the main evaporator and the temperature at which frost occurs on the sub-evaporator, and the cooling space in which the product is stored is cooled. As a result, during the cooling operation of the main evaporator, the sub-evaporator can assist the main evaporator in cooling the air while preventing frost on the sub-evaporator. As a result, there is no need to perform an operation for defrosting the sub-evaporator, and the amount of frost on the main evaporator can be reduced compared to when air is cooled only by the main evaporator, so that the main evaporator can be defrosted in a short time and with a low heat load. In addition, the main evaporator and the sub-evaporator are provided in the first air flow path and the second air flow path, which are provided separately from each other. As a result, the sub-evaporator can cool the air more efficiently when the main evaporator is defrosted, compared to when the main evaporator and the sub-evaporator are provided in the same air flow path. As a result, the temperature rise in the cooling space (inside the cabinet) during defrosting of the main evaporator can be suppressed compared to when the main evaporator and the sub evaporator are installed in the same air flow path. As a result, the increase in heat load during defrosting of the evaporator (main evaporator) can be suppressed, and the temperature inside the cabinet can be easily maintained.

In the cooling device according to the above aspect, the main evaporator and the sub-evaporator are preferably arranged so as not to overlap when viewed from the direction in which the first air flow path and the second air flow path are adjacent. This configuration makes it possible to suppress an increase in the size of the cooling device in the direction in which the first air flow path and the second air flow path are adjacent, compared to a case in which the main evaporator and the sub-evaporator overlap when viewed from the direction in which the first air flow path and the second air flow path are adjacent.

In the cooling device according to the above aspect, preferably, the first air flow path in which the main evaporator is provided is disposed closer to the cooling space than the second air flow path in which the sub-evaporator is provided. With this configuration, the first air flow path in which the main evaporator is provided is disposed closer to the cooling space than the second air flow path in which the sub-evaporator is provided, so that the main evaporator, in which the temperature of the refrigerant flowing through it is lower than the temperature of the refrigerant flowing through the sub-evaporator during cooling operation, can be disposed on the cooling space side. As a result, the cooling temperature of the cooling space (inside the cabinet) can be efficiently maintained.

In the cooling device according to the above aspect, the cooling device preferably further includes a discharge section that discharges air cooled by the main evaporator and the sub-evaporator, and a back air flow path that is provided on the back side of the cooling space and between the cooling space and the first air flow path , and the mixing area mixes the air flowing out from the first air flow path and the air flowing out from the second air flow path, and distributes the air to the discharge section side flow path and the back air flow path. With this configuration, the mixing area can mix the air flowing out from each of the first air flow path and the second air flow path, and distribute it to each of the discharge section side flow path and the back air flow path. As a result, even if the temperature of the refrigerant flowing through each of the main evaporator and the sub evaporator changes during the cooling operation and the defrosting operation of the main evaporator, the temperature of the air distributed to each of the discharge section side flow path and the back air flow path during each operation can be suppressed, so that the temperature of the cooling space (inside the storage unit) can be easily maintained.

The cooling device according to the above aspect preferably further includes a wall portion provided downstream of the mixing region so as to block a portion of the air flowing out from the first air flow path and the second air flow path to be mixed by the mixing region. With this configuration, the wall portion blocks a portion of the air flowing out from the first air flow path and the second air flow path downstream of the mixing region, thereby making it possible to circulate the air flowing out from each of the first air flow path and the second air flow path in a vortex manner in the mixing region. As a result, the air flowing out from each of the first air flow path and the second air flow path can be efficiently mixed in the mixing region.

In the cooling device according to the above aspect , preferably, the cooling device further includes an induction section for guiding the air flowing out from at least one of the first air flow path and the second air flow path to the mixing region. With this configuration, the induction section guides the air flowing out from at least one of the first air flow path and the second air flow path to the mixing region, so that the air flowing out from each of the first air flow path and the second air flow path can be mixed more efficiently in the mixing region. As a result, the temperature variation of the air distributed to each of the discharge side flow path and the rear air flow path can be more efficiently suppressed.

In the configuration in which the mixing area mixes the air flowing out from the first air flow path and the air flowing out from the second air flow path and distributes the air to the flow path on the discharge section side and the rear air flow path , preferably, a dividing member is further provided for dividing the air flow path between the mixing area and the discharge section into an outer air flow path and an inner air flow path arranged closer to the cooling space than the outer air flow path, the discharge section is configured to discharge cooled air from above downward, and includes an inner discharge section provided in communication with the inner air flow path for forming an inner air curtain that blocks the cooling space from outside air, and an outer discharge section provided in communication with the outer air flow path for forming an outer air curtain outside the inner air curtain that blocks the cooling space from outside air, the outer air flow path and the second air flow path are provided outside the inner air flow path and the first air flow path, respectively, with respect to the cooling space. With this configuration, even if the air is not sufficiently mixed in the mixing area during the cooling operation of the main evaporator, the air cooled by the auxiliary evaporator, whose flowing refrigerant has a higher temperature than the main evaporator, is likely to flow from the second air flow path into the outer air flow path. As a result, even if the air is not sufficiently mixed in the mixing area during cooling operation of the main evaporator, the temperature of the inner air curtain can be made lower than the temperature of the outer air curtain. This makes it possible to lower the temperature of the air curtain on the cooling space side (inside the cabinet) during cooling operation of the main evaporator, making it easy to maintain the temperature of the cooling space (inside the cabinet).

In the configuration in which the mixing area mixes the air flowing out from the first air flow path and the air flowing out from the second air flow path and distributes the air to the flow path on the discharge section side and the rear air flow path, the mixing area is preferably provided on the rear side of the cooling space and between the cooling space and the rear air flow path so as to extend in the vertical direction, and further includes a plate-shaped rear plate having rear air blowing holes for discharging the air mixed by the mixing area from the rear air flow path to the cooling space in the horizontal direction, and a horizontal discharge hole for discharging the air cooled by the main evaporator in the first air flow path from the first air flow path to the rear air flow path in the horizontal direction. With this configuration, the air flowing through the rear air flow path can be pushed out from the rear air blowing holes by discharging the air cooled by the main evaporator in the first air flow path from the first air flow path to the rear air flow path in the horizontal direction. As a result, the air mixed in the mixing area after cooling by the main evaporator and the sub evaporator and flowing through the rear air flow path can be easily sent from the rear air blowing holes to the cooling space, so that the cooling space (interior) can be cooled more effectively.

In the cooling device according to the above aspect, the temperature of the refrigerant flowing through the sub-evaporator during defrosting operation of the main evaporator is preferably configured to be lower than the temperature of the refrigerant flowing through the main evaporator during cooling operation of the main evaporator, and the sub-evaporator is configured to have a larger heat transfer area than the main evaporator. With this configuration, the sub-evaporator has a larger heat transfer area than the main evaporator provided in the first air flow path, so the heat transfer efficiency of the sub-evaporator is improved compared to when the heat transfer areas of the main evaporator and the sub-evaporator are approximately the same. As a result, even when the sub-evaporator cools the air during defrosting operation of the main evaporator, the cooling space S (inside the storage unit) can be stably cooled (temperature maintained).

In the cooling device according to the above aspect, preferably, the first air flow path and the second air flow path are formed to extend in the vertical direction so that the air to be cooled flows from the bottom to the top, and above the main evaporator in the first air flow path, an inclined portion is further provided that inclines inwardly as it moves upward. With this configuration, moisture contained in the air flowing through the first air flow path hits the inclined portion and condenses, thereby reducing the moisture content of the air flowing downstream of the inclined portion. As a result, an increase in humidity of the air flowing out of the first air flow path can be suppressed.

In the cooling device according to the above aspect, preferably, a temperature sensor is provided in the first air flow path at least one of downstream of the main evaporator and the outer surface of the main evaporator to detect temperature. With this configuration, when the temperature sensor is provided downstream of the main evaporator, the temperature sensor can detect the temperature change of the air cooled by the main evaporator, so that the completion of defrosting of the main evaporator can be easily detected. Also, when the temperature sensor is provided on the outer surface of the main evaporator, the temperature sensor can detect the temperature change of the outer surface of the main evaporator, so that the completion of defrosting of the main evaporator can be easily detected.

As described above, the present invention provides a cooling device that can easily maintain the temperature inside the refrigerator by suppressing the increase in heat load when defrosting the evaporator.

1 is a diagram showing an example of a schematic configuration of a cooling device according to a first embodiment of the present invention; 1 is a cross-sectional view of a cooling device according to a first embodiment. FIG. 4 is a cross-sectional view showing a first air flow path and a second air flow path. FIG. 4 is a partial enlarged view of the periphery of an inclined portion of FIG. 3 . FIG. 4 is a partially enlarged view of the periphery of a mixed region in FIG. 3 . FIG. 11 is a partial cross-sectional view of the periphery of an inclined portion of a cooling device according to a second embodiment. FIG. 11 is a partial cross-sectional view of the periphery of a discharge hole of a cooling device according to a third embodiment. FIG. 10 is a cross-sectional view of a cooling device according to a fourth embodiment. FIG. 11 is a cross-sectional view of a cooling device according to a modified example.

The following describes an embodiment of the present invention with reference to the drawings.

[First embodiment]
The overall configuration of a cooling device 100 according to a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the cooling device 100 includes a compressor 10 and a condenser 20. The compressor 10 is configured to compress a refrigerant. The compressor 10 is controlled by an inverter (not shown). As a result, the compressor 10 is configured to be able to adjust the flow rate of the refrigerant discharged from the compressor 10. The refrigerant is, for example, R410A, R404A, R32, carbon dioxide (CO ₂ ), or the like. The condenser 20 is configured to condense the refrigerant discharged from the compressor 10. In addition, the condenser 20 is provided with a blower fan 21. The blower fan 21 is configured to send air to the condenser 20. Then, heat is transferred from the refrigerant in the condenser 20 to the air sent by the blower fan 21.

The cooling device 100 also includes first expansion valves 31 and 32 and evaporators 41 and 42. The first expansion valves 31 and 32 are configured to expand the refrigerant condensed by the condenser 20. The compressor 10 and the condenser 20 are provided in common for the evaporators 41 and 42. The first expansion valves 31 and 32 are, for example, needle valves. The openings of the first expansion valves 31 and 32 are adjusted by stepping motors (not shown) attached to the first expansion valves 31 and 32. The flow rates of the refrigerant to the evaporators 41 and 42 provided downstream of the first expansion valves 31 and 32 are adjusted by adjusting the openings of the first expansion valves 31 and 32.

The evaporators 41 and 42 are configured to evaporate the refrigerant condensed by the condenser 20. The evaporators 41 and 42 are configured to evaporate the refrigerant expanded by the first expansion valves 31 and 32, respectively. The evaporators 41 and 42 are arranged in parallel with each other. The evaporators 41 and 42 include a refrigerant flow path through which the refrigerant flows and a heat transfer surface that transfers the temperature of the refrigerant. Specifically, the evaporators 41 and 42 include a plurality of flat plates arranged in parallel with each other and made of a metal such as aluminum. The flat plates are made of a metal such as aluminum. The front and back surfaces of the flat plates are heat transfer surfaces. The refrigerant flow path penetrates the plurality of flat plates and is arranged in a meandering manner. The evaporators 41 and 42 are examples of the "main evaporator" and "auxiliary evaporator" in the claims, respectively.

The evaporator 42 is configured to have a larger heat transfer area than the evaporator 41. In other words, as described above, the evaporator 42 is configured to have a larger heat transfer surface area (surface area) than the evaporator 41.

The cooling device 100 also includes a blower fan 43. The blower fan 43 is configured to send air to the evaporators 41 and 42. The blower fan 43 is also provided to circulate the taken-in outside air through a first air flow path A1 and a second air flow path A2, which will be described later. In other words, the blower fan 43 is provided in common to the evaporators 41 and 42 (the first air flow path A1 and the second air flow path A2).

The cooling device 100 also includes a second expansion valve 51 that expands the refrigerant flowing out of the evaporator 42. The second expansion valve 51 is, for example, a needle valve, similar to the first expansion valves 31 and 32. The opening of the second expansion valve 51 is adjusted by a stepping motor (not shown) attached to the second expansion valve 51. The flow rate of the refrigerant to the evaporator 42 provided upstream is adjusted (controlled) by adjusting the opening of the second expansion valve 51. That is, the refrigerant pressure (amount of refrigerant) in the evaporator 42 is controlled according to the opening of the second expansion valve 51. The second expansion valve 51 also throttles the refrigerant passing through it to create a pressure loss (pressure difference). That is, the evaporation pressure (evaporation temperature) and refrigerant temperature in the upstream evaporator 42 rise by the amount of the pressure loss caused by the second expansion valve 51, relative to the low pressure (suction pressure) determined by the rotation speed of the compressor 10.

The cooling device 100 also includes temperature sensors 61 and 62. The temperature sensor 61 is configured to detect the temperature in the first air flow path A1, which will be described later. The temperature sensor 62 is configured to detect the temperature downstream of the second air flow path A2, which will be described later. The signals (detection signals) based on the detection results of the temperature sensors 61 and 62 are also configured to be transmitted to the control unit 70.

The cooling device 100 also includes a control unit 70. The control unit 70 is configured to control the entire cooling device 100. Specifically, the control unit 70 is configured to control the opening degrees of the first expansion valve 31, the first expansion valve 32, and the second expansion valve 51. The control unit 70 is also configured to control the operation of the compressor 10, the blower fan 21, and the blower fan 43. The control unit 70 includes a CPU (Central Processing Unit) and a memory.

As shown in FIG. 2, the cooling device 100 is a vertical showcase that includes a plate-shaped back panel 80 extending in the vertical direction (Z direction) and multiple shelves 81 on which products are placed. The cooling device 100 is a refrigerated showcase in which multiple shelves 81 are arranged and that cools the cooling space S (interior) in which products are stored to a chilled temperature range. For example, the cooling device 100 is configured to cool the cooling space S in the range of -2°C to 6°C. In this specification, the vertical direction is the Z direction, the front-rear direction is the X direction, and the left-right direction is the Y direction. The upward direction is the Z1 direction, and the downward direction is the Z2 direction. The front side of the cooling device 100 is the X1 direction, and the back side (rear side) of the cooling device 100 is the X2 direction. When viewed from the front side (X1 direction) of the cooling device 100, the right side is the Y1 direction, and the left side is the Y2 direction.

As shown in FIG. 2, the cooling device 100 has an intake port 91 and an exhaust port 92. The cooling device 100 is configured to cool the outside air (air) sucked in through the intake port 91 by the evaporators 41 and 42. The exhaust port 92 is configured to exhaust the air cooled by the evaporators 41 and 42 from above downward (Z2 direction side). The exhaust port 92 is an example of the "exhaust section" in the claims.

As shown in FIG. 2, the cooling device 100 includes a first air flow path A1 in which an evaporator 41 is provided, and a second air flow path A2 in which an evaporator 42 is provided. The second air flow path A2 is provided separately from the first air flow path A1.

The cooling device 100 also includes a rear air flow path A3, as shown in FIG. 2. The rear air flow path A3 is provided on the rear side (X2 direction side) of the cooling space S, and between the cooling space S and the first air flow path A1.

The rear panel 80 is disposed on the rear side (X2 direction side) of the cooling space S, between the cooling space S and the rear air flow path A3, so as to extend in the vertical direction (Z direction).

As shown in FIG. 2, the blower fan 43 is provided in the flow path between the intake port 91 and the first air flow path A1 (second air flow path A2). As described above, the blower fan 43 is provided in common to the evaporators 41 and 42 (first air flow path A1 and second air flow path A2). Note that the blower fan 43 may be provided corresponding to each of the evaporators 41 and 42 (first air flow path A1 and second air flow path A2). Furthermore, a plurality of blower fans 43 may be provided adjacent to each other in the left-right direction (Y direction).

As shown in FIG. 2, the cooling device 100 also includes dividing members 93, 94, and 95. The dividing members 93, 94, and 95 are provided in the flow path between the intake port 91 (blower fan 43) and the exhaust port 92.

The dividing member 93 is provided between the evaporator 41 and the evaporator 42. The dividing member 93 is configured to divide the space in the flow path between the suction port 91 and the discharge port 92, and to branch the outside air drawn into the suction port 91 into the first air flow path A1 and the second air flow path A2.

The dividing member 94 is provided between the evaporator 41 and the rear plate 80. The dividing member 94 divides the space between the rear plate 80 and the dividing member 93 (evaporator 41), and is configured to form the first air flow path A1 together with the dividing member 93. The dividing member 94 is configured to form the rear air flow path A3 together with the rear plate 80.

The first air flow path A1, in which the evaporator 41 is provided, is disposed closer to the cooling space S (X1 direction side) than the second air flow path A2, in which the evaporator 42 is provided.

The first air flow path A1 and the second air flow path A2 are formed to extend in the vertical direction (Z direction) so that the cooling air flows from below to above.

The dividing member 95 is configured to form an inner air flow path A4 and an outer air flow path A5. As shown in FIG. 2, the dividing member 95 is configured to divide the air flow path between the mixing region M and the discharge port 92 described later into an outer air flow path A5 and an inner air flow path A4 that is arranged closer to the cooling space S than the outer air flow path A5. The outer air flow path A5 and the second air flow path A2 are provided outside the inner air flow path A4 and the first air flow path A1, respectively, with respect to the cooling space S (on the opposite side to the side where the cooling space S is arranged with respect to the inner air flow path A4 and the first air flow path A1, respectively).

As shown in FIG. 2, the evaporator 41 and the evaporator 42 are arranged so as not to overlap when viewed from the direction in which the first air flow path A1 and the second air flow path A2 are adjacent (the X1 direction side or the X2 direction side). The evaporator 41 is arranged below the evaporator 42 (the Z2 direction side). The evaporator 41 and the evaporator 42 are arranged so as to partially overlap when viewed from above (the Z1 direction side) or below (the Z2 direction side).

As shown in FIG. 2, the discharge port 92 includes an inner discharge port 92a and an outer discharge port 92b. The inner discharge port 92a is provided in communication with the inner air flow path A4. The air discharged from the inner discharge port 92a forms an inner air curtain C1 that blocks the cooling space S from the outside air. The outer discharge port 92b is provided in communication with the outer air flow path A5. The air discharged from the outer discharge port 92b forms an outer air curtain C2 that blocks the cooling space S from the outside air. The outer air curtain C2 is formed outside (X1 direction side) the inner air curtain C1. Specifically, the outer air curtain C2 is formed on the opposite side (X1 direction side) of the inner air curtain C1 from the side where the cooling space S is arranged. The inner discharge port 92a is an example of an "inner discharge portion" in the claims, and the outer discharge port 92b is an example of an "outer discharge portion" in the claims. Additionally, the inner air curtain C1 is an example of an "inner air curtain" in the claims, and the outer air curtain C2 is an example of an "outer air curtain" in the claims.

The rear plate 80 also has rear air blowing holes 80a (see Figures 2 and 3) for discharging the air mixed by the mixing area M described below from the rear air flow path A3 toward the cooling space S in the horizontal direction (X direction). Multiple rear air blowing holes 80a are provided on the rear plate 80.

The cooling device 100 maintains (cools) the temperature of the cooling space S (interior) where the products are stored by discharging air cooled by the evaporators 41 and 42 from the outlets 92 (inner outlets 92a and outer outlets 92b) and the rear blowing holes 80a provided in the rear panel 80.

(Inclined portion)
4, the first air flow path A1 is configured such that the flow path width W2 on the downstream side (Z1 direction side) is smaller (narrower) than the flow path width W1 at the portion where the evaporator 41 is disposed. The cooling device 100 includes inclined portions 93a and 94a that are inclined inwardly upward above the evaporator 41 in the first air flow path A1 (Z1 direction side). Specifically, the dividing members 93 and 94 have inclined portions 93a and 94a, respectively, that are inclined inwardly upward on the downstream side (Z1 direction side) of the evaporator 41 so that the distance between them becomes narrower.

The flow path width W1 of the first air flow path A1 at the portion where the evaporator 41 is disposed is configured to be larger (wider) than the flow path width W3 upstream (Z2 direction side) of the portion where the evaporator 42 is disposed in the second air flow path A2. In the first embodiment, the flow path width W3 is configured to be larger (wider) than the flow path width W2.

In the first embodiment, as described above, the blower fan 43 is provided in common for the first air flow path A1 and the second air flow path A2. Therefore, in the cooling device 100, the flow rate of air flowing through the first air flow path A1 and the second air flow path A2 is adjusted (air volume ratio is adjusted) by the flow path width (duct width) of each of the first air flow path A1 and the second air flow path A2. For example, if too much air flows through one of the first air flow path A1 and the second air flow path A2, the flow path width of one is made smaller (narrower) than the flow path width of the other to cause a pressure loss and adjust the air volume ratio.

The temperature sensor 61 is provided on the outer surface of the evaporator 41 in the first air flow path A1, as shown in FIG. 4. Specifically, the temperature sensor 61 is provided on the outer surface (outer surface 41a) of the evaporator 41 downstream (Z1 direction side) of the first air flow path A1. The temperature sensor 61 detects the temperature of the outer surface (outer surface 41a) of the evaporator 41.

(Mixed Region)
5, the cooling device 100 is provided with a mixing region M. The mixing region M is a region where the air flowing out from the first air flow path A1 and the air flowing out from the second air flow path A2 are mixed. In the mixing region M, the mixed air is distributed to the flow paths on the discharge port 92 side (the inner air flow path A4 and the outer air flow path A5) and the rear air flow path A3.

5, the dividing member 94 includes an induction portion 94b. The induction portion 94b is formed near the upper end of the dividing member 94 so as to extend toward the X2 direction side (the second air flow path A2 side) opposite the side where the cooling space S is arranged. The induction portion 94b is configured to induce air flowing out from at least one of the first air flow path A1 and the second air flow path A2 to the mixing region M.

In the first embodiment, the induction section 94b is configured to induce air flowing out of the first air flow path A1 toward the X2 direction side (the second air flow path A2 side), thereby guiding air flowing out of the second air flow path A2 to the mixing region M. The induction section 94b is also formed to cover the evaporator 42 and a part of the second air flow path A2 when viewed from the downstream side (the Z1 direction side) of the evaporator 42. As a result, the induction section 94b induces air flowing out from the dividing member 93 side (the X1 direction side) of the second air flow path A2 toward the X2 direction side.

The dividing member 95 also includes a wall portion 95a. The wall portion 95a is formed so as to extend toward the cooling space S side (X1 direction side) near the lower end of the dividing member 95. The wall portion 95a is provided downstream (Z1 direction side) of the mixing region M, and is provided so as to block a portion of the air flowing out from the first air flow path A1 and the second air flow path A2 that is mixed by the mixing region M. This allows the air flowing out from the first air flow path A1 and the second air flow path A2 to circulate in a swirling manner, allowing efficient mixing.

The temperature sensor 62 is provided on the outer surface of the evaporator 42. Specifically, the temperature sensor 62 is provided on the outer surface (outer surface 42a) of the evaporator 42 downstream (Z1 direction side) of the second air flow path A2. The temperature sensor 62 detects the temperature of the outer surface of the evaporator 42.

(Cooling operation)
The cooling device 100 is configured to switch between cooling operations under the control of the control unit 70. Specifically, the cooling device 100 is configured to perform a first cooling operation in which cooling is performed by the evaporators 41 and 42, and a second cooling operation in which cooling is performed by the evaporator 42 while defrosting the evaporator 41. That is, the cooling device 100 is configured to switch between the cooling operation and the defrosting operation of the evaporator 41.

The first cooling operation has a longer operating time than the second cooling operation. For example, the operating time of the first cooling operation is about 1 to 2 hours, and the operating time of the second cooling operation is about 10 to 15 minutes. In other words, the first cooling operation is the main operation in the cooling operation of the cooling device 100. In addition, in the first cooling operation, the evaporator 42 is defrosted in addition to cooling the air, and in the second cooling operation, the evaporator 41 is defrosted in addition to cooling the air.

During the first cooling operation (during the cooling operation of the evaporator 41 provided in the first air flow path A1), the cooling device 100 is configured to cool the cooling space S in which the product is stored, with the temperature of the refrigerant flowing through the evaporator 42 provided in the second air flow path A2 being higher than the temperature of the refrigerant flowing through the evaporator 41 and the temperature at which frost forms on the evaporator 42.

Specifically, during the cooling operation of the evaporator 41 provided in the first air flow path A1 (first cooling operation), the control unit 70 makes the pressure of the refrigerant flowing through the evaporator 42 higher than the pressure of the refrigerant flowing through the evaporator 41 by the second expansion valve 51, and makes the temperature of the refrigerant flowing through the evaporator 42 provided in the second air flow path A2 higher than the temperature of the refrigerant flowing through the evaporator 41 and the temperature at which frost forms on the evaporator 42.

(First cooling operation)
An example of the first cooling operation in the first embodiment will be described. In the first cooling operation, the control unit 70 controls the evaporation temperature (refrigerant temperature) of the evaporator 41 to about −7° C. by the first expansion valve 31. In addition, the control unit 70 controls the evaporation temperature (refrigerant temperature) of the evaporator 42 to about 1° C. by balancing the opening degrees of the first expansion valve 32 and the second expansion valve 51.

Then, the air (outside air at about 10°C) flowing in from the intake port 91 is branched into the first air flow path A1 and the second air flow path A2 by the blower fan 43. In the first air flow path A1, the air flowing in from the intake port 91 is cooled to about -2°C by the evaporator 41. In the second air flow path A2, the air flowing in from the intake port 91 is dehumidified and cooled to about 2°C by the evaporator 42. At this time, the evaporator 42 cools the air flowing in from the intake port 91 without frosting.

The air cooled to about -2°C (by the evaporator 41) in the first air flow path A1 and the air dehumidified and cooled to about 2°C (by the evaporator 42) in the second air flow path A2 are mixed in the mixing area M (see FIG. 5). In the mixing area M, the wall portion 95a and the induction portion 94b efficiently mix the air flowing out of the first air flow path A1 and the air flowing out of the second air flow path A2.

The air mixed in the mixing area M and cooled to about 0°C flows into the outer air flow path A5 and the inner air flow path A4, and is discharged from the discharge port 92 as the outer air curtain C2 and the inner air curtain C1, respectively. It also flows into the rear air flow path A3, and is discharged into the cooling space S (inside the storage unit) as rear air through the rear air blowing hole 80a.

In addition, in the first embodiment, the temperature of the refrigerant flowing through the evaporator 42 during the second cooling operation (during the defrosting operation of the evaporator 41) is configured to be lower than the temperature of the refrigerant flowing through the evaporator 41 during the first cooling operation (during the cooling operation of the evaporator 41).

(Second cooling operation)
An example of the second cooling operation in the first embodiment will be described. In the first embodiment, the temperature of the refrigerant flowing through the evaporator 42 during the second cooling operation (during the defrosting operation of the evaporator 41) is configured to be lower than the temperature of the refrigerant flowing through the evaporator 42 during the first cooling operation (during the cooling operation of the evaporator 41).

In the second cooling operation, the control unit 70 closes the first expansion valve 31 and stops the supply of refrigerant to the evaporator 41. The temperature of the refrigerant in the evaporator 41 then becomes approximately 5°C. The control unit 70 also opens the second expansion valve 51 to a larger degree than in the first cooling operation, reducing the flow resistance of the refrigerant and lowering the refrigerant temperature. In the second cooling operation, the refrigerant temperature in the evaporator 42 is lowered below the refrigerant temperature in the first cooling operation. For example, the refrigerant temperature is lowered from approximately 1°C in the first cooling operation to approximately -10°C.

Then, the air (outside air at about 10°C) flowing in from the intake 91 is branched into the first air flow path A1 and the second air flow path A2 by the blower fan 43. In the first air flow path A1, the air flowing in from the intake 91 is cooled to about 6°C by the evaporator 41. In the second air flow path A2, the air flowing in from the intake 91 is cooled to about -6°C by the evaporator 42. Note that frost adheres to the evaporator 42 due to the drop in the refrigerant temperature during the second cooling operation, but the frost that adheres to the evaporator 42 during the second cooling operation melts and is removed during the first cooling operation.

Then, as in the first cooling operation, the air (at about 6°C) flowing out of the first air flow path A1 and the air (at about -6°C) flowing out of the second air flow path A2 are mixed in the mixing area M (see FIG. 5). The air mixed in the mixing area M and cooled to about 0°C flows into the outer air flow path A5 and the inner air flow path A4, and is discharged from the discharge port 92 as the outer air curtain C2 and the inner air curtain C1, respectively, and also flows into the rear air flow path A3 and is discharged as rear air into the cooling space S (inside the cabinet) through the rear air blowing hole 80a. This makes it possible to cool the cooling space S (maintain the temperature of the cooling space S) in the same way as in the first cooling operation while defrosting the evaporator 41.

(Effects of the First Embodiment)
In the first embodiment, the following effects can be obtained.

In the first embodiment, during the cooling operation (first cooling operation) of the evaporator 41 provided in the first air flow path A1, the temperature of the refrigerant flowing through the evaporator 42 provided in the second air flow path A2 is set higher than the temperature of the refrigerant flowing through the evaporator 41 and the temperature at which frost occurs on the evaporator 42, and the cooling space S in which the product is stored is cooled. As a result, during the cooling operation (first cooling operation) of the evaporator 41, the evaporator 42 can assist the evaporator 41 in cooling the air while preventing frost on the evaporator 42. As a result, there is no need to perform an operation for defrosting the evaporator 42, and the amount of frost on the evaporator 41 can be reduced compared to when air is cooled only by the evaporator 41, so that the evaporator 41 can be defrosted in a short time with a low heat load. In addition, the evaporators 41 and 42 are provided in the first air flow path A1 and the second air flow path A2, which are provided separately from each other. This allows the evaporator 42 to cool the air more efficiently when the evaporator 41 is defrosted, compared to when the evaporator 41 and the evaporator 42 are provided in the same air flow path. As a result, the temperature rise in the cooling space S (inside the cabinet) when the evaporator 41 is defrosted can be suppressed, compared to when the evaporator 41 and the evaporator 42 are provided in the same air flow path. As a result, the increase in the heat load when the evaporator 41 is defrosted can be suppressed, and the inside temperature can be easily maintained.

In addition, in the first embodiment, as described above, the evaporators 41 and 42 are arranged so as not to overlap when viewed from the direction in which the first air flow path A1 and the second air flow path A2 are adjacent (the X1 direction side or the X2 direction side). This makes it possible to suppress an increase in the size of the cooling device 100 in the direction in which the first air flow path A1 and the second air flow path A2 are adjacent (the X direction) compared to a case in which the evaporators 41 and 42 overlap when viewed from the direction in which the first air flow path A1 and the second air flow path A2 are adjacent.

In the first embodiment, as described above, the first air flow path A1 in which the evaporator 41 is provided is disposed closer to the cooling space S (X1 direction side) than the second air flow path A2 in which the evaporator 42 is provided. As a result, the first air flow path A1 in which the evaporator 41 is provided is disposed closer to the cooling space S (X1 direction side) than the second air flow path A2 in which the evaporator 42 is provided, so that the evaporator 41, in which the temperature of the refrigerant flowing therethrough is lower than the temperature of the refrigerant flowing through the evaporator 42 during the cooling operation of the evaporator 41 (first cooling operation), can be disposed on the cooling space S side. As a result, the cooling temperature of the cooling space S (inside the storage unit) can be efficiently maintained.

In the first embodiment, as described above, the exhaust port 92 that exhausts the air cooled by the evaporators 41 and 42 and the rear air flow path A3 are provided on the rear side (X2 direction side) of the cooling space S and between the cooling space S and the first air flow path A1. The mixing area M is provided to mix the air flowing out from the first air flow path A1 and the air flowing out from the second air flow path A2 and distribute the air to the flow path on the exhaust port 92 side (the inner air flow path A4 and the outer air flow path A5) and the rear air flow path A3. This allows the mixing area M to mix the air flowing out from each of the first air flow path A1 and the second air flow path A2 and distribute the air to each of the flow paths on the exhaust port 92 side (the inner air flow path A4 and the outer air flow path A5) and the flow path on the rear air flow path A3 side. As a result, even if the temperature of the refrigerant flowing through each of the evaporators 41 and 42 changes during the cooling and defrosting operations of the evaporator 41 (first and second cooling operations), the temperature variation of the air distributed to each of the flow paths on the discharge port 92 side (the inner air flow path A4 and the outer air flow path A5) and the rear air flow path A3 during each operation can be suppressed, so the temperature of the cooling space S (inside the storage unit) can be easily maintained.

In the first embodiment, as described above, the wall portion 95a is provided downstream (Z1 direction side) of the mixing area M so as to block a portion of the air flowing out from the first air flow path A1 and the second air flow path A2 that is mixed by the mixing area M. As a result, the wall portion 95a blocks a portion of the air flowing out from the first air flow path A1 and the second air flow path A2 downstream (Z1 direction side) of the mixing area M, so that the air flowing out from each of the first air flow path A1 and the second air flow path A2 in the mixing area M can be circulated in a swirling manner. As a result, the air flowing out from each of the first air flow path A1 and the second air flow path A2 can be efficiently mixed in the mixing area M.

In the first embodiment, as described above, the induction section 94b is configured to induce the air flowing out from each of the first air flow path A1 and the second air flow path A2 to the mixing area M. As a result, the induction section 94b induces the air flowing out from each of the first air flow path A1 and the second air flow path A2 to the mixing area M, so that the air flowing out from each of the first air flow path A1 and the second air flow path A2 can be mixed more efficiently in the mixing area M. As a result, the temperature variation of the air distributed to each of the flow paths on the discharge section side (the inner air flow path A4 and the outer air flow path A5) and the rear air flow path A3 can be more efficiently suppressed.

In the first embodiment, as described above, the outer air flow path A5 and the second air flow path A2 are provided outside the inner air flow path A4 and the first air flow path A1, respectively, with respect to the cooling space S. As a result, even if the air is not sufficiently mixed in the mixing area M during the cooling operation of the evaporator 41 (first cooling operation), the air cooled by the evaporator 42, whose temperature of the refrigerant flowing therethrough is higher than that of the evaporator 41, is likely to flow from the second air flow path A2 into the outer air flow path A5. As a result, even if the air is not sufficiently mixed in the mixing area M during the cooling operation of the evaporator 41 (first cooling operation), the temperature of the inner air curtain C1 can be made lower than the temperature of the outer air curtain C2. As a result, the temperature of the air curtain on the cooling space S side (inside the storage unit) can be made lower during the cooling operation of the evaporator 41 (first cooling operation), so that the temperature of the cooling space S (inside the storage unit) can be easily maintained.

In the first embodiment, as described above, the temperature of the refrigerant flowing through the evaporator 42 during the defrosting operation of the evaporator 41 (second cooling operation) is configured to be lower than the temperature of the refrigerant flowing through the evaporator 41 during the cooling operation of the evaporator 41 (first cooling operation). The evaporator 42 is configured to have a larger heat transfer area than the evaporator 41. As a result, the evaporator 42 has a larger heat transfer area than the evaporator 41 provided in the first air flow path A1, and therefore the heat transfer efficiency of the evaporator 42 is improved compared to when the heat transfer areas of the evaporator 41 and the evaporator 42 are approximately the same. As a result, even when the evaporator 42 cools the air during the defrosting operation of the evaporator 41 (second cooling operation), the cooling space S (inside the storage unit) can be cooled (temperature maintained) stably.

In the first embodiment, as described above, the first air flow path A1 and the second air flow path A2 are formed to extend in the vertical direction (Z direction) so that the air to be cooled flows from the bottom to the top. The inclined portions 93a and 94a are configured to incline inwardly as they move upward above the evaporator 41 of the first air flow path A1. This allows the moisture contained in the air flowing through the first air flow path A1 to hit the inclined portions 93a and 94a and condense, thereby reducing the amount of moisture in the air flowing downstream of the inclined portions 93a and 94a. As a result, it is possible to suppress an increase in the humidity of the air flowing out of the first air flow path A1.

In the first embodiment, as described above, the temperature sensor 61 is provided on the outer surface (outer surface 41a) of the evaporator 41 in the first air flow path A1 and is configured to detect the temperature. This allows the temperature sensor 61 to detect a change in temperature of the outer surface (outer surface 41a) of the evaporator 41, making it easy to detect the completion of defrosting of the evaporator 41.

[Second embodiment]
The configuration of a cooling device 200 according to the second embodiment will be described with reference to Fig. 6. In the figure, the same reference numerals are used to designate the same components as those in the first embodiment.

In the cooling device 200 of the second embodiment, unlike the cooling device 100 of the first embodiment in which the temperature sensor 261 is provided on the outer surface (outer surface 41a) of the evaporator 41 in the first air flow path A1, the temperature sensor 261 is provided downstream of the evaporator 41 so as to be spaced apart from the evaporator 41 in the first air flow path A1. The temperature sensor 261 is configured to detect the temperature of the air cooled by the evaporator 41 downstream of the evaporator 41.

The rest of the configuration of the second embodiment is the same as that of the first embodiment.

(Effects of the Second Embodiment)
In the second embodiment, the following effects can be obtained.

In the second embodiment, as in the first embodiment, the increase in thermal load during defrosting of the evaporator 41 is suppressed, making it easy to maintain the temperature inside the cabinet.

In addition, in the second embodiment, as described above, the temperature sensor 261 is provided downstream of the evaporator 41 in the first air flow path A1 and is configured to detect the temperature. This allows the temperature sensor 261 to detect the temperature change of the air cooled by the evaporator 41, making it easy to detect the completion of defrosting of the evaporator 41.

The other effects of the second embodiment are the same as those of the first embodiment.

[Third embodiment]
The configuration of a cooling device 300 according to the third embodiment will be described with reference to Fig. 7. In the figure, the same reference numerals are used to designate the same components as those in the first embodiment.

The cooling device 300 is provided with a plate-shaped rear plate 80 having rear blowing holes 80a for discharging the air mixed by the mixing region M from the rear air flow path A3 toward the cooling space S in the horizontal direction, as in the first embodiment. The cooling device 300 also has discharge holes 394c for discharging the air cooled by the evaporator 41 in the first air flow path A1 from the first air flow path A1 toward the rear air flow path A3 (X1 direction side) in the horizontal direction. The discharge holes 394c are holes provided in the dividing member 94 so as to communicate from the first air flow path A1 to the rear air flow path A3. The discharge holes 394c are an example of the "horizontal discharge holes" in the claims. A plurality of discharge holes 394c are provided in the dividing member 94.

In the third embodiment, the air cooled by the evaporator 41 in the first air flow path A1 and discharged from the discharge hole 394c is configured to push out the air flowing through the rear air flow path A3, thereby assisting in the discharge of air from the rear air hole 80a.

The rest of the configuration of the third embodiment is the same as that of the first embodiment.

(Effects of the Third Embodiment)
In the third embodiment, the following effects can be obtained.

In the third embodiment, as in the first embodiment, the increase in heat load during defrosting of the evaporator 41 is suppressed, making it easy to maintain the temperature inside the cabinet.

In the third embodiment, as described above, a plate-shaped rear plate 80 having rear blowing holes 80a for discharging the air mixed by the mixing region M from the rear air flow path A3 toward the cooling space S along the horizontal direction is provided. And, a discharge hole 394c for discharging the air cooled by the evaporator 41 in the first air flow path A1 from the first air flow path A1 toward the rear air flow path A3 along the horizontal direction is provided. As a result, the air flowing through the rear air flow path A3 can be pushed out from the rear blowing holes 80a by discharging the air cooled by the evaporator 41 in the first air flow path A1 from the first air flow path A1 toward the rear air flow path A3 along the horizontal direction. As a result, the air mixed in the mixing region M after cooling by the evaporator 41 and the evaporator 42 and flowing through the rear air flow path A3 can be easily sent from the rear blowing holes 80a to the cooling space S, so that the cooling space S (inside the storage) can be cooled more effectively.

The other effects of the third embodiment are the same as those of the first embodiment.

[Fourth embodiment]
The configuration of a cooling device 400 according to a fourth embodiment will be described with reference to Fig. 8. In the figure, the same reference numerals are used to designate the same components as those in the first embodiment.

Unlike the cooling device 100 according to the first embodiment having the mixing region M, the cooling device 400 according to the fourth embodiment is configured to discharge the air cooled by the evaporators 41 and 42 without mixing them. In the cooling device 400, the air flow path between the intake port 91 (blower fan 43) and the exhaust port 92 is divided by a dividing member 493 into a first air flow path B1 in which the evaporator 41 is provided and a second air flow path B2 in which the evaporator 42 is provided. In the cooling device 400, the evaporator 41 is disposed below the evaporator 42 (Z2 direction side). In addition, the cooling device 400 includes an inclined portion 493a above the evaporator 41 of the first air flow path B1 (Z1 direction side) that inclines inward as it goes upward. Specifically, the dividing member 493 has an inclined portion 493a that is inclined toward the cooling space S (X1 direction side) above the evaporator 41 of the first air flow path B1 (Z1 direction side). The inclined portion 493a is provided above the evaporator 41 (Z1 direction side) and below the evaporator 42 (Z2 direction side).

The second air flow path B2 is disposed on the opposite side of the first air flow path B1 from the side where the cooling space S is disposed. That is, the first air flow path B1 in which the evaporator 41 is disposed is disposed closer to the cooling space S (X1 direction side) than the second air flow path B2 in which the evaporator 42 is disposed. The air cooled in the first air flow path B1 in which the evaporator 41 is disposed is discharged as an inner air curtain C1 from the inner discharge port 92a, and is also discharged as a rear air curtain into the cooling space S (inside the cabinet) through the rear air blowing hole 80a (see FIG. 3). The air cooled in the second air flow path B2 in which the evaporator 42 is disposed is discharged as an outer air curtain C2 from the outer discharge port 92b.

(Cooling operation)
The cooling device 400 is configured to switch between cooling operations under the control of the control unit 70. Specifically, similar to the cooling device 100 according to the first embodiment, the cooling device 400 is configured to perform a first cooling operation in which cooling is performed by the evaporators 41 and 42, and a second cooling operation in which cooling is performed by the evaporator 42 while defrosting the evaporator 41. That is, the cooling device 400 is configured to switch between the cooling operation and the defrosting operation of the evaporator 41.

(First cooling operation)
An example of the first cooling operation in the fourth embodiment (cooling device 400) will be described. In the first cooling operation, the control unit 70 controls the evaporation temperature (refrigerant temperature) of the evaporator 41 to -7°C by the first expansion valve 31. In addition, the control unit 70 controls the evaporation temperature (refrigerant temperature) of the evaporator 42 to 1°C by balancing the opening degrees of the first expansion valve 32 and the second expansion valve 51.

Then, the air (outside air at about 12°C) flowing in from the intake 91 is branched into the first air flow path B1 and the second air flow path B2 by the blower fan 43. In the first air flow path B1, the air flowing in from the intake 91 is cooled to about -2°C by the evaporator 41. The air cooled to about -2°C by the evaporator 41 is discharged from the inner discharge port 92a as an inner air curtain C1, and is also discharged as a rear airflow into the cooling space S (inside the storage unit) through the rear airflow hole 80a.

In addition, in the second air flow path B2, the air flowing in from the suction port 91 is dehumidified and cooled to about 2°C by the evaporator 42. At this time, the evaporator 42 cools the air flowing in from the suction port 91 without frosting. The air dehumidified and cooled to about 2°C by the evaporator 42 is discharged from the outer discharge port 92b as the outer air curtain C2.

(Second cooling operation)
An example of the second cooling operation in the fourth embodiment (cooling device 400) will be described. In the fourth embodiment, the temperature of the refrigerant flowing through the evaporator 42 during the second cooling operation (during the defrosting operation of the evaporator 41) is configured to be lower than the temperature of the refrigerant flowing through the evaporator 42 during the first cooling operation (during the cooling operation of the evaporator 41).

In the second cooling operation, the control unit 70 closes the first expansion valve 31 and stops the supply of refrigerant to the evaporator 41. The temperature of the refrigerant in the evaporator 41 then becomes approximately 5°C. The control unit 70 also opens the second expansion valve 51 to a larger degree than in the first cooling operation, reducing the flow resistance of the refrigerant and lowering the refrigerant temperature. In the second cooling operation, the refrigerant temperature in the evaporator 42 is lowered below the refrigerant temperature in the first cooling operation. For example, the refrigerant temperature is lowered from approximately 1°C in the first cooling operation to approximately -7°C.

Then, the air (outside air at about 10°C) flowing in from the intake port 91 is branched into the first air flow path B1 and the second air flow path B2 by the blowing of the blower fan 43. In the first air flow path B1, the air flowing in from the intake port 91 is cooled to about 6°C while defrosting the evaporator 41. The air cooled to about 6°C by the evaporator 41 is discharged as an inner air curtain C1 from the inner discharge port 92a, and is also discharged as a rear air blown into the cooling space S (inside the storage unit) through the rear air blowing hole 80a.

In addition, in the second air flow path B2, the air flowing in from the intake port 91 is cooled to about -2°C by the evaporator 42. The air cooled to about -2°C by the evaporator 42 is discharged as the outer air curtain C2 from the outer discharge port 92b. Note that frost that adheres to the evaporator 42 during the second cooling operation is melted and removed (removed) during the first cooling operation.

The rest of the configuration of the fourth embodiment is the same as that of the first embodiment.

(Effects of the Fourth Embodiment)
In the fourth embodiment, the following effects can be obtained.

In the fourth embodiment, as in the first embodiment, the increase in thermal load during defrosting of the evaporator 41 is suppressed, making it easy to maintain the temperature inside the cabinet.

[Modification]
The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the first to fourth embodiments, the cooling devices 100, 200, 300, and 400 are vertical showcases, but the present invention is not limited to this. For example, the cooling device may be a flat showcase that expels cooled air in a horizontal direction to form an air curtain.

In the above first to fourth embodiments, the evaporators 41 and 42 (main evaporator and sub evaporator) are arranged so as not to overlap when viewed from the direction in which the first air flow path A1 and the second air flow path A2 are adjacent to each other (the X1 direction side or the X2 direction side), but the present invention is not limited to this. In the present invention, the main evaporator and the sub evaporator may overlap when viewed from the direction in which the first air flow path and the second air flow path are adjacent to each other.

In the above first to third embodiments, the first air flow path A1 in which the evaporator 41 (main evaporator) is provided is disposed closer to the cooling space S (X1 direction side) than the second air flow path A2 in which the evaporator 42 (sub-evaporator) is provided. That is, the first air flow path A1 in which the evaporator 41 (main evaporator) is provided and the second air flow path A2 in which the evaporator 42 (sub-evaporator) is provided are disposed in the front-rear direction (X direction) of the cooling device 100, but the present invention is not limited to this. In the present invention, the first air flow path in which the main evaporator is provided and the second air flow path in which the sub-evaporator is provided may be disposed adjacent to each other in the left-right direction (Y direction) rather than in the front-rear direction (X direction) of the cooling device.

In the fourth embodiment, the first air flow path B1 in which the evaporator 41 (main evaporator) is provided is disposed closer to the cooling space S (X1 direction side) than the second air flow path B2 in which the evaporator 42 (sub-evaporator) is provided, and the mixing area M is not provided. However, the present invention is not limited to this. In the present invention, as in the cooling device 500 according to the modified example shown in FIG. 9, the second air flow path D2 in which the evaporator 42 (sub-evaporator) is provided is disposed closer to the cooling space S (X1 direction side) than the first air flow path D1 in which the evaporator 41 (main evaporator) is provided, and the mixing area M may not be provided. In the cooling device 500, the air flow path between the intake port 91 (blower fan 43) and the discharge port 92 is divided by the dividing member 593 into the first air flow path D1 in which the evaporator 41 is provided and the second air flow path D2 in which the evaporator 42 is provided. In the cooling device 500, the evaporator 41 is disposed above the evaporator 42 (Z1 direction side). Furthermore, in the cooling device 500, similarly to the first to fourth embodiments, the temperature of the refrigerant flowing through the evaporator 42 during the second cooling operation (during the defrosting operation of the evaporator 41) is configured to be lower than the temperature of the refrigerant flowing through the evaporator 41 and lower than the temperature of the refrigerant flowing through the evaporator 42 during the first cooling operation (during the cooling operation of the evaporator 41). As a result, the second air flow path D2 in which the evaporator 42 is provided is disposed on the cooling space S side (X1 direction side) than the first air flow path D1 in which the evaporator 41 is provided, so that the evaporator 42, whose temperature of the refrigerant flowing through it is lower than the temperature of the refrigerant flowing through the evaporator 41 during the second cooling operation (during the defrosting operation of the evaporator 41), can be disposed on the cooling space S side. As a result, the cooling temperature of the cooling space S (inside the storage unit) during the second cooling operation (during the defrosting operation of the evaporator 41) can be efficiently maintained.

In the above first embodiment, the dividing member 95 that divides the air flow path between the mixing area M and the discharge port 92 (discharge section) into the outer air flow path A5 and the inner air flow path A4 includes a wall portion 95a, but the present invention is not limited to this. In the present invention, a wall portion that is provided to block a portion of the air that flows out from the first air flow path and the second air flow path that is mixed by the mixing area, and a dividing member that divides the air flow path between the mixing area and the discharge section may be provided separately.

In the first to third embodiments, an example is shown in which the induction section 94b is provided to induce the air flowing out from each of the first air flow path A1 and the second air flow path A2 to the mixing region M, but the present invention is not limited to this. In the present invention, the induction section may be configured to induce the air flowing out from the first air flow path of the first air flow path and the second air flow path to the mixing region. As a result, the induction section 94b induces the air flowing out from the first air flow path to the mixing region, so that the air flowing out from each of the first air flow path and the second air flow path can be mixed more efficiently in the mixing region. In the present invention, the induction section may be configured to induce the air flowing out from the second air flow path of the first air flow path and the second air flow path to the mixing region. As a result, the induction section 94b induces the air flowing out from the second air flow path to the mixing region, so that the air flowing out from each of the first air flow path and the second air flow path can be mixed more efficiently in the mixing region.

In addition, in the above first to third embodiments, an example was shown in which a dividing member 95 was provided to divide the air flow path between the mixing region M and the discharge port 92 (discharge section) into an outer air flow path A5 and an inner air flow path A4 that is disposed closer to the cooling space S than the outer air flow path A5, but the present invention is not limited to this. In the present invention, a dividing member for dividing the air flow path between the mixing region and the discharge section may be omitted, and the air mixed by the mixing region may be discharged directly from the discharge section without being branched.

In addition, in the above first to fourth embodiments, the evaporator 42 (auxiliary evaporator) is configured to have a larger heat transfer area than the evaporator 41 (main evaporator), but the present invention is not limited to this. In the present invention, the heat transfer area of the auxiliary evaporator may be smaller than the heat transfer area of the main evaporator, or the heat transfer areas of the main evaporator and the auxiliary evaporator may be approximately the same.

In the above first embodiment, the temperature sensor 62 is provided on the outer surface 42a of the evaporator 42 (sub-evaporator), but the present invention is not limited to this. In the present invention, a temperature sensor that detects the temperature of the air cooled by the sub-evaporator may be provided downstream of the sub-evaporator (second air flow path) and separated from the sub-evaporator.

In the above first embodiment, an example is shown in which one evaporator 41 (main evaporator) is provided in the first air flow path A1, but the present invention is not limited to this. In the present invention, multiple main evaporators (two or more) may be provided in the first air flow path.

In the above first embodiment, an example was shown in which one evaporator 42 (sub-evaporator) is provided in the second air flow path A2, but the present invention is not limited to this. In the present invention, multiple sub-evaporators (two or more) may be provided in the second air flow path.

10 Compressor 20 Condenser 41 Evaporator (main evaporator)
42 Evaporator (secondary evaporator)
61, 261 Temperature sensor 80 Rear plate 80a Rear blowing hole 92 Discharge port (discharge section)
92a Inner discharge port (inner discharge part)
92b Outside discharge port (outside discharge part)
93a, 94a, 493a Inclined portion 94b Guide portion 95 Dividing member 95a Wall portion 100, 200, 300, 400, 500 Cooling device 394c Discharge hole (horizontal discharge hole)
A1, B1, D1 First air flow path A2, B2, D2 Second air flow path A3 Rear air flow path A4 Inner air flow path A5 Outer air flow path C1 Inner air curtain (inner air curtain)
C2 Outer air curtain
M Mixing area S Cooling space

Claims (11)

A compressor that compresses a refrigerant;
a condenser that condenses the refrigerant discharged from the compressor;
a main evaporator and a sub evaporator for evaporating the refrigerant condensed by the condenser;
a first air flow path in which the main evaporator is disposed;
the sub-evaporator is provided therein, and a second air flow path is provided separately from the first air flow path;
The main evaporator is configured to be switched between a cooling operation and a defrosting operation,
During a cooling operation of the main evaporator provided in the first air flow path, a cooling space in which a commodity is stored is cooled in a state in which a temperature of the refrigerant flowing through the sub-evaporator provided in the second air flow path is set higher than a temperature of the refrigerant flowing through the main evaporator and a temperature at which frost forms on the sub-evaporator,
The cooling device further includes a mixing region that mixes the air flowing out of the first air flow path and the air flowing out of the second air flow path . The cooling device according to claim 1, wherein the main evaporator and the sub evaporator are arranged so as not to overlap when viewed from a direction in which the first air flow path and the second air flow path are adjacent to each other. The cooling device according to claim 1 or 2, wherein the first air flow passage in which the main evaporator is provided is disposed closer to the cooling space than the second air flow passage in which the sub-evaporator is provided. a discharge portion that discharges air cooled by the main evaporator and the sub-evaporator;
A rear air flow path is provided on a rear side of the cooling space and between the cooling space and the first air flow path ,
The cooling device according to any one of claims 1 to 3, wherein the mixing area mixes the air flowing out of the first air flow path and the air flowing out of the second air flow path, and distributes the mixed air to the discharge side flow path and the rear air flow path. 2. The cooling device according to claim 1, further comprising a wall portion provided downstream of the mixing area so as to block a portion of the air flowing out of the first air flow path and the second air flow path that is mixed by the mixing area . The cooling device according to claim 1 , further comprising an induction section for guiding the air flowing out of at least one of the first air flow path and the second air flow path to the mixing region. a dividing member for dividing an air flow path between the mixing region and the discharge portion into an outer air flow path and an inner air flow path disposed closer to the cooling space than the outer air flow path,
the discharge section is configured to discharge cooled air from above downward, and includes an inner discharge section provided in communication with the inner air flow path for forming an inner air curtain that blocks the cooling space from outside air, and an outer discharge section provided in communication with the outer air flow path for forming an outer air curtain outside the inner air curtain that blocks the cooling space from outside air,
The cooling device according to claim 4 , wherein the outer air flow path and the second air flow path are provided outside the cooling space relative to the inner air flow path and the first air flow path, respectively. a plate-shaped rear plate that is provided on the rear side of the cooling space and between the cooling space and the rear air flow passage so as to extend in a vertical direction, and has rear air blowing holes for discharging the air mixed in the mixing area from the rear air flow passage toward the cooling space in a horizontal direction;
5. The cooling device according to claim 4, further comprising a horizontal discharge hole for discharging the air cooled by the main evaporator in the first air flow path from the first air flow path toward the rear air flow path along a horizontal direction. a temperature of the refrigerant flowing through the sub-evaporator during a defrosting operation of the main evaporator is made lower than a temperature of the refrigerant flowing through the main evaporator during a cooling operation of the main evaporator,
9. The cooling device according to claim 1, wherein the sub-evaporator is configured to have a larger heat transfer area than the main evaporator. The first air flow path and the second air flow path are formed to extend in a vertical direction so that the air to be cooled flows from below to above,
The cooling device according to any one of claims 1 to 9, further comprising an inclined portion inclined inwardly as it extends upward, above the main evaporator in the first air flow path. The cooling device according to any one of claims 1 to 10, further comprising a temperature sensor that is provided in the first air flow path at least one of downstream of the main evaporator and on the outer surface of the main evaporator to detect a temperature.

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