JP2010139234A - Freezing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out operation with significantly superior energy saving performance in a freezing unit carrying out cooling of an interior by a cooling heat exchanger. <P>SOLUTION: The freezing unit includes: a first control unit (53) that adjusts the cooling performance of an evaporator (14) so that the internal temperature is at a target temperature; a second control unit (54) that increases the cooling performance of the evaporator (14) to lower the internal temperature to a second lower temperature limit, and then stops a compressor (11) and also opens an automatic ventilation opening (7) to introduce outside air into the unit once the temperature is maintained at the target temperature; and a third control unit (55) that causes control operation by the first control unit (53) to resume when the internal temperature subsequently reaches an upper temperature limit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

    The present invention relates to a refrigeration apparatus provided with a cooling heat exchanger for cooling the inside of a warehouse, and particularly to an energy saving operation method of the refrigeration apparatus.

    DESCRIPTION OF RELATED ART Conventionally, the freezing apparatus for cooling the insides, such as a refrigerator and a freezer, is known.

    For example, Patent Document 1 discloses a refrigeration apparatus that cools the inside of a container used for marine transportation or the like. This refrigeration apparatus includes a refrigerant circuit to which a compressor, a condenser, an expansion valve, and a cooling heat exchanger (evaporator) are connected. In the refrigerant circuit of this refrigeration apparatus, the refrigerant circulates to perform a vapor compression refrigeration cycle. As a result, the refrigerant flowing through the cooling heat exchanger absorbs heat from the internal air and evaporates, thereby cooling the internal air.

    In the refrigeration apparatus as described above, high temperature accuracy of, for example, about ± 0.5 ° C. is required with respect to the target temperature in accordance with the conveyed item in the container. Therefore, the compressor was always operated with priority given to ensuring temperature accuracy. However, once the air inside the container cools, the cooling load does not change so much, and it is unlikely that the outside temperature that affects the cooling load will change so rapidly. Thus, for example, as disclosed in Patent Document 2, a refrigeration apparatus having an energy saving operation mode in which a compressor is operated intermittently has been proposed.

    In the energy saving operation mode of the refrigeration apparatus of Patent Document 2, when the internal temperature is maintained at the target temperature, the cooling capacity of the cooling heat exchanger is increased to temporarily reduce the internal temperature to the lower limit value of the target temperature range. The compressor is stopped later. Thereafter, when the internal temperature rises to the upper limit value of the target temperature range, the compressor is started again, and this cycle is repeated. Thus, since the compressor is operated intermittently, the operation time of the compressor is shortened as a whole, and the energy consumption of the compressor is reduced.

JP 2002-327964 A Japanese Patent No. 3864899

    By the way, in the refrigerating apparatus of the above-mentioned patent document 2, since the compressor is merely operated intermittently, the energy saving performance cannot be sufficiently improved by itself.

    This invention is made | formed in view of this point, The objective is to enable it to perform the driving | operation which was remarkably excellent in energy-saving property in the freezing apparatus which cools the inside of a store | warehouse | chamber with a cooling heat exchanger.

    The first invention is a refrigeration apparatus comprising a refrigerant circuit (10) in which a cooling heat exchanger (14) and a compressor (11) for cooling the interior are connected, and a refrigerant circulates to perform a refrigeration cycle. Is assumed. The refrigeration apparatus according to the present invention includes a capacity adjusting means (35) for adjusting the cooling capacity of the cooling heat exchanger (14) so that the inside temperature becomes a target temperature, and outside air introduction for introducing outside air into the inside. Means (7). Furthermore, the refrigeration apparatus of the present invention includes a first control unit (53) that operates the compressor (11) while adjusting the cooling capacity of the cooling heat exchanger (14) by the capacity adjusting means (35), When the internal temperature is maintained at the target temperature during the control operation by the first control unit (53), the cooling capacity of the cooling heat exchanger (14) is increased by the capacity adjusting means (35) to increase the target temperature. After lowering the internal temperature to a predetermined temperature that is equal to or higher than the lower limit value of the target range including the above and below the target temperature, the compressor (11) is stopped, and the external temperature is equal to or lower than the internal temperature When the inside temperature reaches the upper limit of the target range during the control operation by the second control unit (54) for introducing outside air into the cabinet by the outside air introduction means (7) and the second control unit (54), Start the compressor (11) and guide the outside air by the outside air introduction means (7) The prohibited in which and a third control unit (55) to resume the control operation by the first control unit (53).

    In the first invention, the refrigerant is circulated in the refrigerant circuit (10) to perform a vapor compression refrigeration cycle. As a result, the refrigerant flowing through the cooling heat exchanger (14) absorbs heat from the internal air and evaporates, thereby cooling the internal space.

    Here, in the refrigeration apparatus of the present invention, an energy saving operation (hereinafter referred to as an energy saving operation) in which the compressor (11) is intermittently operated is performed. Specifically, in this energy saving operation, the following first operation to third operation are repeatedly performed by each control unit (53, 54, 55). In this refrigeration apparatus, a target temperature of the internal temperature and an upper limit value and a lower limit value of a target range (allowable temperature range) including the target temperature are set.

    First, the first operation is performed by the first control unit (53). In this first operation, the compressor (11) is operated, and the cooling capacity of the cooling heat exchanger (14) is adjusted by the capacity adjusting means (35). As a result, the internal temperature gradually approaches the target temperature. When the internal temperature is maintained at the target temperature by the first operation, the second operation by the second control unit (54) is performed.

    In the second operation, the compressor (11) is operated and the cooling capacity of the cooling heat exchanger (14) is increased by the capacity adjusting means (35). As a result, the internal temperature gradually decreases. When the internal temperature reaches a predetermined temperature that is equal to or higher than the lower limit value and lower than the target temperature, the compressor (11) is stopped. Further, when the outside temperature is equal to or lower than the inside temperature, the outside air is introduced into the warehouse by the outside air introducing means (7) when the compressor (11) is stopped.

    During the second operation, since the compressor (11) remains stopped, the refrigeration cycle is not performed in the refrigerant circuit (10), and the cooling in the warehouse by the cooling heat exchanger (14) is substantially stopped. The As a result, the internal temperature gradually increases and reaches the upper limit of the target range. Here, in the second operation, since the outside air below the inside temperature is continuously introduced into the inside, the rising speed of the inside temperature is suppressed. Then, when the internal temperature reaches the upper limit value, the third operation by the third control unit (55) is performed. In the third operation, the compressor (11) is started again and the introduction of outside air is prohibited, and the first operation by the first control unit (53) is resumed. When the first operation is resumed, the internal temperature approaches the target temperature again.

    In a second aspect based on the first aspect, the outside air introduction means is an openable / closable vent (7) for ventilating the inside of the warehouse. Then, the second control unit (54) stops the compressor (11), and when the outside temperature is equal to or lower than the inside temperature, opens the ventilation port (7) to let outside air into the inside. On the other hand, the third control unit (55) activates the compressor (11) and closes the vent (7) to prohibit the introduction of outside air.

    In the second invention, the ventilation port (7) for ventilating the inside of the warehouse is used as the outside air introducing means. This ventilation port (7) is originally provided for discharging a gas such as carbon dioxide that is expelled when a transported product such as fruits and vegetables matures during transportation. In energy-saving operation, the ventilation port (7) is opened during the second operation and outside air is introduced, the ventilation port (7) is closed during the third operation, and the introduction of outside air is prohibited during the first operation. The

    According to a third invention, in the first or second invention, an internal fan (16) for blowing the internal air to the cooling heat exchanger (14) and blowing the internal air again into the internal combustion chamber is provided. The second control unit (54) reduces the operating temperature of the internal fan (16) after lowering the internal temperature to the predetermined temperature, while the third control unit (55) When the internal temperature reaches the upper limit of the target range, the operating rotational speed of the internal fan (16) is increased.

    In the third invention, the internal fan (16) is operated at a normal rotational speed during the first operation of the energy saving operation. As a result, the refrigerant flowing through the cooling heat exchanger (14) and the internal air blown by the internal fan (16) exchange heat. For this reason, the refrigerant absorbs heat from the internal air and evaporates, thereby cooling the internal space.

    On the other hand, during the second operation in which the compressor (11) is stopped, the internal fan (16) is operated at a lower rotational speed than in the first operation. For this reason, the amount of heat generated from the internal fan (16) when the internal fan (16) is driven is smaller than that during the first operation. As a result, since the time until the inside temperature reaches the upper limit during the second operation is prolonged, the stop time of the compressor (11) is also prolonged. Therefore, the power consumption of the refrigeration apparatus during this energy saving operation is reduced.

    According to a fourth invention, in the first or second invention, an internal fan (16) for blowing the internal air to the cooling heat exchanger (14) and blowing out the internal air again. The second control unit (54) lowers the internal temperature to the predetermined temperature and then stops the internal fan (16), while the third control unit (55) When the upper limit value of the target range is reached, the internal fan (16) is activated.

    In the fourth invention, the internal fan (16) is operated at a normal rotational speed during the first operation of the energy saving operation. As a result, the refrigerant flowing through the cooling heat exchanger (14) and the internal air blown by the internal fan (16) exchange heat. For this reason, the refrigerant absorbs heat from the internal air and evaporates, thereby cooling the internal space.

    On the other hand, during the second operation in which the compressor (11) is stopped, the internal fan (16) is stopped. For this reason, since the internal fan (16) does not generate heat during the second operation, the time until the internal temperature reaches the upper limit is further prolonged. Therefore, the power consumption of the refrigeration apparatus during this energy saving operation is further reduced.

    According to a fifth invention, in the first or second invention, an internal fan (16) for blowing the internal air to the cooling heat exchanger (14) and blowing the internal air again into the internal combustion chamber is provided. The second control unit (54) sets the predetermined temperature to a temperature higher than the lower limit value of the target range, lowers the internal temperature to the predetermined temperature, and then the internal fan (16). When the operating speed is decreased and then the internal temperature exceeds the predetermined temperature, the internal fan (16) is stopped, while the third control unit (55) is configured such that the internal temperature is the upper limit value of the target range. When this is reached, the internal fan (16) is started.

    In the fifth invention, in the second operation, when the internal temperature is lowered to a temperature higher than the lower limit value of the target range, the compressor (11) is stopped and outside air is introduced, and the internal fan (16) is operated at a low rotational speed. In this state, the rate of increase in the internal temperature is suppressed by the introduction of outside air, and the amount of heat generated by the internal fan (16) is suppressed, so that the rate of increase in the internal temperature is further suppressed. When the internal temperature rises and exceeds a predetermined temperature, the internal fan (16) is stopped. As a result, the amount of heat generated by the internal fan (16) is eliminated, and the rate of increase of the internal temperature is further suppressed.

    In the second operation of the present invention, the amount of reduction of the internal temperature is small compared to the case where the internal temperature is lowered to the lower limit value of the target range. If it does so, it will also be considered that the time for the internal temperature to reach the upper limit is shortened. However, in the second operation of the present invention, as described above, the rate of increase in the internal temperature is remarkably slow, so that it is not significantly affected by the small reduction width of the internal temperature. Furthermore, according to the present invention, the operating time of the compressor (11) required for the reduction is shortened by the amount by which the internal temperature is reduced.

    In a sixth aspect based on the first or second aspect, the capacity adjusting means is connected to the refrigerant circuit (10) and adjusts the flow rate of the refrigerant sucked into the compressor (11) ( 35). And the said 2nd control part (54) enlarges the opening degree of the said flow regulating valve (35), and increases the cooling capacity of the said cooling heat exchanger (14).

    In the sixth invention, the flow rate adjusting valve (35) is connected to the refrigerant circuit (10). The flow rate adjusting valve (35) constitutes capacity adjusting means for adjusting the cooling capacity of the cooling heat exchanger (14) by adjusting the flow rate of the refrigerant sucked in the compressor (11).

    Specifically, during the first operation of the energy saving operation, the refrigerant circulation amount in the refrigerant circuit (10) is adjusted by adjusting the opening degree of the flow rate adjustment valve (35). Here, if the refrigerant circulation amount is adjusted by narrowing the opening degree of the flow rate adjustment valve (35), the refrigerant becomes wet in almost the entire area of the cooling heat exchanger (14) serving as an evaporator. For this reason, if the cooling capacity of the evaporator is adjusted by adjusting the opening of the expansion valve on the inflow side of the evaporator, the refrigerant flowing through the evaporator becomes dry and the refrigerant flows from the inflow end to the outflow end of the evaporator. However, if the cooling capacity of the cooling heat exchanger (14) is adjusted while reducing the opening of the flow rate adjusting valve (35) as in the present invention, the cooling heat exchanger (14) The temperature distribution of the refrigerant from the inflow end to the outflow end is made uniform. As a result, the internal air is cooled to a relatively uniform temperature by the cooling heat exchanger (14).

    When the internal temperature is maintained at the target temperature by adjusting the opening of the flow rate adjusting valve (35) in the first operation, the second operation is performed. In this second operation, the amount of refrigerant circulating in the refrigerant circuit (10) is increased and the cooling capacity of the cooling heat exchanger (14) is increased by largely adjusting the opening of the flow rate adjusting valve (35).

    In a seventh aspect based on the sixth aspect, the second control section (54) lowers the internal temperature to the predetermined temperature, and then the third control section (55) causes the first control section (53 ) Until the control operation is resumed, the opening of the flow rate adjusting valve (35) is held at the opening when the internal temperature is lowered.

    In the seventh invention, in the second operation, when the opening degree of the flow rate adjustment valve (35) increases and the internal temperature is lowered to a predetermined temperature, the opening degree of the flow rate adjustment valve (35) at that time is maintained as it is. Is done. The opening degree of the flow rate adjusting valve (35) is maintained as it is until the compressor (11) is restarted by the third operation. For this reason, the opening degree of the flow rate adjustment valve (35) at the start of the first operation is the time when the immediately preceding second operation has been completed, which has increased the cooling capacity of the cooling heat exchanger (14) to cool the internal air. The opening is the same as the opening. As a result, a sufficient refrigerant circulation amount is ensured from the start of the first operation in which the internal temperature reaches the upper limit value and the compressor (11) restarts. For this reason, the internal air is quickly cooled, and the internal temperature quickly approaches the target temperature.

    According to an eighth invention, in the first to seventh inventions, the compressor (11) is continuously connected while adjusting the cooling capacity of the cooling heat exchanger (14) by the capacity adjusting means (35). A normal operation control unit (51) that operates automatically, and an energy saving operation control unit (52) configured by the first control unit (53), the second control unit (54), and the third control unit (55). I have. And this invention, the suction temperature sensor (RS) which detects the temperature of the internal air sent to the said cooling heat exchanger (14), and the said suction temperature sensor during control operation by the said normal operation control part (51) An operation switching unit (56) for switching to a control operation by the energy saving operation control unit (52) when the detected temperature of (RS) falls within a predetermined temperature range including the target temperature is provided.

    In the eighth invention, during the operation (during normal operation) by the normal operation control unit (51), the compressor (11) is continuously operated while the cooling capacity of the cooling heat exchanger (14) is adjusted. The operation is performed so that the internal temperature approaches the target temperature. Further, on the upstream side of the cooling heat exchanger (14), a suction temperature sensor (RS) for measuring the temperature of the internal air sent to the cooling heat exchanger (14) is provided.

    Here, in the present invention, the operation switching unit (56) determines the operation switching from the normal operation to the operation (energy saving operation) by the energy saving operation control unit (52). Specifically, during normal operation, the suction temperature detected by the suction temperature sensor (RS) is compared with the target temperature. When the suction temperature is outside the predetermined temperature range including the target temperature, it is necessary to quickly bring the internal temperature close to the target temperature, so that the normal operation is continued. On the other hand, if the suction temperature is within the specified temperature range including the target temperature, the internal temperature is already near the target temperature and there is no need to operate the compressor (11) continuously. It is moved to.

    According to a ninth invention, in the first to seventh inventions, the compressor (11) is continuously connected while the cooling capacity of the cooling heat exchanger (14) is adjusted by the capacity adjusting means (35). A normal operation control unit (51) that operates automatically, and an energy saving operation control unit (52) configured by the first control unit (53), the second control unit (54), and the third control unit (55). I have. And this invention is performing control operation by the blowing temperature sensor (SS) which detects the temperature of the air in a warehouse which passes the said cooling heat exchanger (14) and blows off in a warehouse, and the said normal operation control part (51) And an operation switching unit (56) for switching to a control operation by the energy saving operation control unit (52) when the temperature detected by the blowout temperature sensor (SS) falls within a predetermined temperature range including the target temperature. .

    In the ninth invention, during the operation (normal operation) by the normal operation control unit (51), the compressor (11) is continuously operated while the cooling capacity of the cooling heat exchanger (14) is adjusted. The operation is performed so that the internal temperature approaches the target temperature. Further, an outlet temperature sensor (SS) is provided on the downstream side of the cooling heat exchanger (14). This blowing temperature sensor (SS) detects the temperature of the inside air after being cooled by the cooling heat exchanger (14).

    Here, in the present invention, unlike the above-described eighth invention, the operation switching unit (56) compares the blowing temperature detected by the blowing temperature sensor (SS) with the target temperature, thereby changing from the normal operation to the energy saving operation control unit. Judgment of transition to operation (energy saving operation) by (52) is performed. Specifically, during normal operation, a comparison is made between the blowing temperature detected by the blowing temperature sensor (SS) and the target temperature. When the blowout temperature is out of the predetermined temperature range including the target temperature, it is necessary to quickly bring the inside temperature close to the target temperature, so that the normal operation is continued. On the other hand, if the blowout temperature is within the specified temperature range including the target temperature, the internal temperature is already close to the target temperature and there is no need to operate the compressor (11) continuously. It is moved to.

    According to a tenth aspect of the present invention, in any one of the second to ninth aspects, a gas concentration sensor (GS) for detecting the concentration of carbon dioxide in the warehouse is provided. The second control unit (54) lowers the internal temperature to the predetermined temperature, and then opens the vent (7) so that the detected concentration of the gas concentration sensor (GS) becomes a set concentration. Is to adjust.

    In the tenth invention, during the second operation of the energy saving operation, the concentration of carbon dioxide in the warehouse becomes the set concentration by adjusting the opening of the ventilation port (7). When the concentration of carbon dioxide in the chamber is higher than the set concentration, the amount of carbon dioxide in the chamber is decreased by increasing the opening of the ventilation port (7) and increasing the ventilation amount. When the concentration of carbon dioxide in the chamber is lower than the set concentration, the amount of carbon dioxide in the chamber is increased by decreasing the opening of the ventilation port (7) and decreasing the ventilation amount. Thereby, the carbon dioxide in a store | warehouse | chamber is hold | maintained at a suitable density | concentration, and the maturation effect | action of the fruits and vegetables as a conveyed product is suppressed, for example.

    As described above, according to the present invention, during the energy saving operation, the compressor (11) is intermittently operated, and when the compressor (11) is stopped, the outside air below the inside temperature is brought into the inside of the warehouse. I introduced it. Therefore, the rising speed of the internal temperature can be suppressed in the second operation, and the time for the internal temperature to reach the upper limit value can be prolonged. Thereby, the stop time of a compressor (11) can be lengthened and the driving power of a compressor (11) can be reduced. As a result, the energy saving performance of the refrigeration apparatus can be improved.

    In particular, in the present invention, the compressor (11) is stopped after the internal temperature is once lowered to the lower limit value. For this reason, according to the present invention, as compared with the case where the compressor is stopped without once reducing the internal temperature to the lower limit value, the time until the internal temperature reaches the upper limit value can be prolonged, The compressor (11) can be stopped for that much. Therefore, the driving power of the compressor (11) can be further reduced, and the energy consumed by the refrigeration apparatus can be effectively reduced.

    Moreover, according to 2nd invention, the ventilator (7) was utilized as an external air introduction means, and low temperature external air was introduce | transduced into the store | warehouse | chamber. Therefore, it is not necessary to newly provide outside air introduction means for introducing outside air into the warehouse. As a result, downsizing and cost reduction of the refrigeration apparatus can be achieved.

    In addition, the ventilation port (7) is not used frequently for the purpose of ventilation. Therefore, by using the ventilation port (7) as the outside air introducing means as in the present invention, the ventilation port (7) can be effectively used.

    According to the third invention, the internal fan (16) is operated at a low rotational speed during the second operation. For this reason, the amount of heat generated by the internal fan (16) during the second operation can be suppressed, and the stop time of the compressor (11) can be prolonged. Therefore, the driving power of the compressor (11) can be further reduced, and the energy saving performance of the refrigeration apparatus can be further effectively improved.

    Further, if the internal fan is completely stopped during the second operation, the air temperature distribution in the internal space may be uneven, and whether the internal temperature has reached the upper limit, There is a possibility that the start time of the third operation cannot be accurately determined. On the other hand, in the present invention, since the rotation speed of the internal fan (16) is only low, the temperature unevenness of the internal air can be kept small. Therefore, in the present invention, since the start time of the third operation can be accurately determined, the internal temperature can be more reliably maintained within the target range.

    On the other hand, when the internal fan (16) is completely stopped only during the second operation as in the fourth invention, the internal fan (16) during the second operation can be prevented from generating heat. The temperature rise in the warehouse during the second operation can be positively suppressed. Therefore, the stop time of the compressor (11) can be extended, and the power consumption of the refrigeration apparatus can be effectively reduced. Further, since the operating power of the internal fan (16) can be reduced by the amount that the internal fan (16) is stopped during the second operation, the energy saving performance of the refrigeration apparatus can be further improved.

    According to the fifth invention, the internal fan (16) is operated at a lower rotational speed during the second operation than during the first operation. Therefore, since the amount of heat generated by driving the motor of the internal fan (16) can be suppressed during the second operation, it takes a long time for the internal temperature to reach the upper limit temperature after the compressor (11) is stopped. Can be Thereby, the stop time of a compressor (11) can be prolonged and the energy-saving property of this freezing apparatus can further be improved.

    Furthermore, in the second operation, the internal fan (16) is stopped when the internal temperature rises to some extent. As a result, the amount of heat generated by the motor of the internal fan (16) can be eliminated, and the duration of the second operation can be prolonged. Therefore, the energy saving performance of the refrigeration apparatus can be further improved.

    According to the sixth aspect of the invention, the cooling capacity of the cooling heat exchanger (14) is adjusted by adjusting the flow rate of the suction refrigerant of the compressor (11) by the flow rate adjusting valve (35). For this reason, in the cooling heat exchanger (14), a damp refrigerant accumulates in the entire area, so that the temperature of the air that has passed through the cooling heat exchanger (14) can be made uniform. That is, if the cooling capacity of the cooling heat exchanger (14) is adjusted by the flow rate adjusting valve (35) as in the present invention, the controllability of the internal temperature can be improved. As a result, during the first operation, the internal temperature can be brought close to the target temperature quickly and reliably. During the second operation, the compressor (11) can be stopped when the internal temperature reaches the predetermined temperature without fail, and thereafter, the internal temperature can be prevented from falling below the lower limit.

    Further, in the second operation as described above, if the operating capacity (for example, operating frequency) of the compressor is increased to increase the cooling capacity of the cooling heat exchanger, the power consumption increases. In the present invention, the degree of opening of the flow rate adjustment valve (35) is only greatly adjusted, so that the cooling capacity of the cooling heat exchanger (14) can be increased without causing such an increase in power consumption. .

    According to the seventh invention, the opening degree of the flow rate adjustment valve (35) when the internal temperature is lowered to the predetermined temperature in the second operation is the second operation, that is, the first operation (third operation) is started. I kept it until just before. Accordingly, since the refrigerant circulation amount can be secured from the start of the first operation in which the internal temperature reaches the upper limit and the compressor (11) restarts, the internal air can be cooled quickly, and the internal temperature reaches the upper limit. It can be avoided in advance.

    In addition, according to the eighth and ninth inventions, it is automatically determined to shift from the operation (normal operation) by the normal operation control unit (51) to the operation (energy saving operation) by the energy saving operation control unit (52). I have to. In particular, in the eighth aspect of the invention, the normal operation is continued until the suction temperature of the internal air before passing through the cooling heat exchanger (14) falls within the target temperature range. Here, since the suction temperature is the temperature of the air in the cabinet before being cooled by the cooling heat exchanger (14), the suction temperature is close to the actual temperature in the cabinet. For this reason, when the transition determination to the energy saving operation is performed based on the suction temperature, the actual internal temperature can be quickly brought into the target temperature range and then the energy saving operation can be shifted to. Therefore, since the conveyed item in the warehouse can be reliably cooled within the target temperature range, an operation that places importance on the quality of the conveyed item can be performed.

    On the other hand, in the ninth invention, the normal operation is continued until the temperature of the air in the warehouse after passing through the cooling heat exchanger (14) falls within the target temperature range. Here, since the blowout temperature is the temperature of the air in the cabinet after being cooled by the cooling heat exchanger (14), the temperature is slightly lower than the actual temperature in the cabinet. For this reason, when the shift determination to the energy saving operation is performed based on the suction temperature, the energy saving operation is shifted to an earlier timing than the eighth invention. Therefore, since energy-saving operation is actively performed, it is possible to perform an operation that emphasizes energy-saving performance with the refrigeration apparatus.

    According to the tenth invention, in the second operation of the energy saving operation, the automatic ventilation port (7) is not simply opened, but the automatic ventilation port ( The opening degree of 7) was adjusted. Therefore, in the second operation, the CO2 concentration in the warehouse can be maintained at an appropriate concentration for fruits and vegetables while introducing low-temperature outside air into the warehouse. As a result, it is possible to extend the stop time of the compressor (11) to improve the energy saving performance and to reliably maintain the freshness of the fruits and vegetables.

FIG. 1 is a perspective view showing a refrigeration container. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a refrigerant circuit diagram of the refrigeration apparatus according to the embodiment. FIG. 4 is a schematic diagram showing the relationship between the automatic ventilation port and the controller. FIG. 5 is a refrigerant circuit diagram showing a refrigerant flow during operation of the refrigeration apparatus. FIG. 6 is a time chart for explaining the first operation in the energy saving operation mode according to the embodiment. FIG. 7 is a time chart for explaining the second operation in the energy saving operation mode according to the embodiment. FIG. 8 is a flowchart showing switching control between the normal operation mode and the energy saving operation mode according to the embodiment. FIG. 9 is a time chart for explaining the second operation in the energy saving operation mode according to the first modification of the embodiment. FIG. 10 is a flowchart illustrating a control operation during the second operation in the energy saving operation mode according to the second modification of the embodiment. FIG. 11 is a flowchart showing the control operation during the second operation in the energy saving operation mode according to the second modification of the embodiment together with FIG. 10.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

    As shown in FIG. 1 and FIG. 2, the refrigeration apparatus (1) of the present embodiment is provided in a container (C) for land transportation or sea transportation, and cools (refrigerates or freezes) the interior of the container. It is. The refrigeration apparatus (1) is attached so as to close the front opening of the container (C) formed in a rectangular box.

    The refrigeration apparatus (1) includes a main body wall (2) and a partition wall (5), a refrigerant circuit (10), an external fan (15) and an internal fan (16), and a controller (50). Yes.

    The main body wall (2) is formed of a heat insulating material or the like, and is tightly fixed to the front opening of the container (C) to close the opening. The main body wall (2) has a generally concave upper part (4) whose upper half is a flat part (3) and whose lower half is recessed inward (inner side) from the flat part (3). The partition wall (5) is provided in parallel with the main body wall (2) and on the inner side (inner side) from the main body wall (2).

    The concave portion (4) of the main body wall (2) forms an outer space (S1) on the outer side (outer side). In addition, an internal upper space (S2) is formed between the flat portion (3) of the main body wall (2) and the partition wall (5), and the concave portion (4) and the partition wall (5 of the main body wall (2) are formed. ), A lower space (S3) inside the cabinet is formed. The upper part of the warehouse inner upper space (S2) and the lower part of the warehouse inner lower space (S3) communicate with the inside of the container warehouse.

    The above-mentioned outside space (S1) is provided with the above-described outside fan (15), a compressor (11), a condenser (12) and the like which will be described later. The above-described internal fan (16) and an evaporator (14) described later are disposed in the internal upper space (S2).

    As shown in FIG. 3, a compressor (11), a condenser (12), an expansion valve (13), and an evaporator (14) are connected to the refrigerant circuit (10) as main components. .

    The compressor (11) is a fixed-capacity scroll compressor in which the rotation speed of the compressor motor is constant.

    The condenser (12) constitutes a so-called air-cooled condenser. An outside fan (15) is provided in the vicinity of the condenser (12). The outside fan (15) blows outside air (outdoor air) to the condenser (12). In the condenser (12), heat is exchanged between the outdoor air blown by the outdoor fan (15) and the refrigerant. An outside temperature sensor (OS) is provided in the vicinity of the condenser (12). This outside temperature sensor (OS) detects the temperature of the outside air sent to the condenser (12) (that is, the outside temperature).

    The expansion valve (13) is an electronic expansion valve whose opening degree can be adjusted. The opening of the expansion valve (13) is adjusted according to the degree of superheat of the refrigerant flowing out of the evaporator (14).

    The said evaporator (14) comprises the cooling heat exchanger for cooling the inside of a store | warehouse | chamber. An internal fan (16) is provided in the vicinity of the evaporator (14). The in-compartment fan (16) sucks in-compartment air from the in-compartment inlet and circulates it through the evaporator (14), and then blows out again from the in-compartment outlet. In the evaporator (14), heat is exchanged between the internal air blown by the internal fan (16) and the refrigerant. In addition, the inlet and outlet of the air in the warehouse are gaps on the upper and lower sides of the partition wall (5) in FIG. 2, respectively. That is, the refrigeration apparatus (1) of the present embodiment is a so-called bottom blowing type.

    Two temperature sensors are provided in the vicinity of the evaporator (14). Specifically, a suction temperature sensor (RS) is provided near the inlet side of the evaporator (14), and a blowout temperature sensor (SS) is provided near the outlet side of the evaporator (14). Yes. The suction temperature sensor (RS) detects the temperature of the internal air sent to the evaporator (14). The blowout temperature sensor (SS) detects the temperature of the air in the compartment that passes through the evaporator (14) and blows out into the compartment.

    The discharge pipe (21) of the compressor (11) is connected to the inflow end of the condenser (12) through the check valve (31) and the discharge pressure adjustment valve (32) in this order. The outflow end of the condenser (12) is connected to the expansion valve (13) through the receiver (33), the first solenoid valve (41), and the high pressure side flow path (34a) of the economizer heat exchanger (34) in this order. ing. The suction pipe (22) of the compressor (11) is connected to the outflow end of the evaporator (14) via a suction proportional valve (35). The inflow end of the evaporator (14) is connected to the expansion valve (13).

    The economizer heat exchanger (34) exchanges heat between the refrigerant flowing through the high-pressure channel (34a) and the refrigerant flowing through the low-pressure channel (34b). The inflow end of the low-pressure channel (34b) is connected between the condenser (12) and the receiver (33) through the capillary tube (36) and the second electromagnetic valve (42) in this order. The outflow end of the low-pressure channel (34b) is connected to the intermediate suction port (11a) of the compressor (11). The intermediate suction port (11a) opens in a path in the middle of compression of the refrigerant in the compression mechanism of the compressor (11).

    The suction proportional valve (35) constitutes a flow rate adjustment valve that adjusts the refrigerant circulation amount in the refrigerant circuit (10) by adjusting the amount of refrigerant sucked by the compressor (11). That is, the suction proportional valve (35) constitutes a capacity adjusting means for adjusting the cooling capacity of the evaporator (14) by adjusting the refrigerant circulation amount. The opening degree of the suction proportional valve (35) is adjusted according to the temperature detected by a temperature sensor inside the container (not shown) provided in the container.

    The refrigerant circuit (10) is connected to a first defrost pipe (23), a second defrost pipe (24), a discharge gas bypass pipe (25), and a liquid injection pipe (26).

    The first defrost pipe (23) and the second defrost pipe (24) introduce a refrigerant discharged from the compressor (11) into the evaporator (14), and defrost operation for melting frost attached to the evaporator (14). Piping. One end of the first defrost pipe (23) and the second defrost pipe (24) is connected between the check valve (31) and the discharge pressure regulating valve (32), and the other end is evaporated with the expansion valve (13). Connected to the container (14). The first defrost pipe (23) is provided with a third electromagnetic valve (43) that is opened during the defrost operation. The second defrost pipe (24) is provided with a fourth solenoid valve (44) and a drain pan heater (37) that are opened during the defrost operation. This drain pan heater (37) is installed in the drain pan for receiving frost and dew condensation water peeled off from the surface of the evaporator (14) in the container warehouse. For this reason, when the refrigerant discharged from the compressor (11) flows through the drain pan heater (37) during the defrost operation, the frost and dew condensation collected in the drain pan absorb heat from the refrigerant discharged from the compressor (11). Melt. During the defrost operation, the discharge pressure adjustment valve (32) is set to a fully closed state.

    The discharge gas bypass pipe (25) has one end connected between the check valve (31) and the fourth solenoid valve (44), and the other end connected between the evaporator (14) and the suction proportional valve (35). Connected between. The discharge gas bypass pipe (25) is provided with a fifth electromagnetic valve (45) that is appropriately opened according to operating conditions. The discharge gas bypass pipe (25) bypasses the refrigerant discharged from the compressor (11) by bypassing the condenser (12) or evaporator (14) when the cooling capacity of the evaporator (14) becomes excessive. This is a pipe for returning to the suction side of the compressor (11). The discharge gas bypass pipe (25) also serves as an oil return pipe for returning the refrigeration oil in the refrigerant discharged from the compressor (11) to the suction side of the compressor (11).

    The liquid injection pipe (26) is a so-called liquid injection pipe for returning the liquid refrigerant condensed by the condenser (12) to the suction side of the compressor (11). The liquid injection pipe (26) has one end connected between the first solenoid valve (41) and the economizer heat exchanger (34), and the other end connected between the suction proportional valve (35) and the compressor (11). Connected between. The liquid injection pipe (26) is provided with a sixth electromagnetic valve (46) that is appropriately opened according to operating conditions.

    A target temperature in the container store is set in the controller (50). The controller (50) is set with one upper limit temperature and two lower limit temperatures (first lower limit temperature and second lower limit temperature) as the target range of the internal temperature in the energy saving operation mode described later in detail. Yes. The first lower limit temperature constitutes the lower limit value of the target range according to the present invention, and the second lower limit temperature is higher than the first lower limit temperature and lower than the target temperature. Further, the controller (50) is provided with temperature correction means for correcting the upper limit temperature and the first lower limit temperature in the energy saving operation mode.

    As shown in FIG. 4, the refrigeration apparatus (1) is provided with an automatic ventilation opening (7) that can be opened and closed. This automatic ventilation port (7) is conventionally provided for the purpose of taking outside air and discharging the inside air to ventilate the inside of the container. Here, when transporting a transported product such as fruits and vegetables, the fruits and vegetables gradually ripen during transport, and gas such as carbon dioxide (CO2) is generated at that time. When the carbon dioxide produced by the fruits and vegetables is sucked, the fruits and vegetables are further matured, and in the worst case, they may rot. Therefore, in order to suppress the ripening of fruits and vegetables and maintain the freshness, it is necessary to suppress the accumulation of carbon dioxide in the warehouse. In view of this, the refrigeration system (1) ventilates the interior of the refrigerator with an automatic ventilation port (7) to discharge carbon dioxide and the like.

    The automatic ventilation port (7) of this embodiment is provided in the concave part (4) of the main body wall (2), and has an intake port (7a) and an exhaust port (7b). The intake port (7a) communicates with the vicinity of the air outlet in the inner lower space (S3), and the exhaust port (7b) communicates with the vicinity of the inlet port of the upper inner space (S2). Although not shown, the automatic ventilation port (7) is provided with a common damper for opening and closing the intake port (7a) and the exhaust port (7b) at the same time. In the automatic ventilation port (7), when the intake port (7a) and the exhaust port (7b) are opened, the outside air is introduced into the chamber from the intake port (7a) and the inside air is discharged to the exhaust port ( It is discharged from 7b). Further, a gas concentration sensor (GS) that detects the concentration of carbon dioxide in the warehouse is provided in the warehouse. The controller (50) opens the automatic ventilation port (7) according to the detected concentration of the gas concentration sensor (GS) and ventilates the inside of the cabinet.

    And the automatic ventilation port (7) of this embodiment is utilized also as an external air introduction means for introducing low temperature outdoor air into a store | warehouse | chamber in the energy-saving operation mode mentioned later.

    The controller (50) switches between various operations (refrigeration operation, refrigeration operation, defrost operation). In addition, the controller (50) includes a normal operation control unit (51) and an energy saving operation control unit (52) that perform control during refrigeration operation. The normal operation control unit (51) controls the refrigeration operation in a normal operation mode in which the compressor (11) is continuously operated while adjusting the cooling capacity of the cooling heat exchanger (14). The energy saving operation control unit (52) includes a first control unit (53), a second control unit (54), and a third control unit (55), and controls the refrigeration operation in the energy saving operation mode. The controller (50) includes an operation switching unit (56) that switches between a normal operation mode and an energy saving operation mode under a predetermined condition in the refrigeration operation. Specific control operations of these controllers (50) will be described later.

-Driving action-
This refrigeration system (1) cools the interior to a temperature lower than zero degrees Celsius and freezes the goods in the warehouse, and cools the interior to a temperature higher than zero degrees Celsius, Refrigeration operation (chilled operation) for refrigeration and the above-described defrost operation can be switched. Here, the refrigeration operation which is a feature of the present invention will be described.

    In the refrigeration operation, a normal operation mode and an energy saving operation mode (hereinafter referred to as an energy saving operation mode) are possible. The normal operation mode is an operation mode in which the compressor (11) and the internal fan (16) are continuously operated and the internal air is continuously cooled by the evaporator (14) to refrigerate the goods in the storage. is there. On the other hand, in the energy saving operation mode, the compressor (11) is operated intermittently, and the air in the warehouse is cooled semi-continuously by the evaporator (14). It is an operation mode to do.

<Normal operation mode>
First, the normal operation mode of the refrigeration apparatus (1) will be described with reference to FIG. In the normal operation mode, the operation is controlled by the normal operation control unit (51). Specifically, in this normal operation mode, the compressor (11) is continuously operated, and the openings of the expansion valve (13) and the suction proportional valve (35) are appropriately adjusted. In this normal operation mode, as a general rule, the first and second solenoid valves (41, 42) are opened, and at the same time, the third to sixth solenoid valves (43, 44, 45, 46) are closed. The outside fan (15) and the inside fan (16) are operated at a normal rotation speed.

    The refrigerant compressed by the compressor (11) flows into the condenser (12) through the discharge pipe (21). In the condenser (12), the refrigerant dissipates heat to the outside air and condenses. Thereafter, a part of the refrigerant flows into the high-pressure channel (34a) of the economizer heat exchanger (34) via the receiver (33), while the rest is decompressed when passing through the capillary tube (36). It flows into the low pressure side flow path (34b) of the economizer heat exchanger (34).

    In the economizer heat exchanger (34), the refrigerant flowing through the low-pressure channel (34b) absorbs heat from the refrigerant flowing through the high-pressure channel (34a) and evaporates. That is, in the economizer heat exchanger (34), the refrigerant flowing through the high-pressure side flow path (34a) is supercooled. The refrigerant evaporated in the low pressure side flow path (34b) is sucked into the intermediate suction port (11a) of the compressor (11).

    The refrigerant supercooled in the high-pressure side flow path (34a) is reduced in pressure when passing through the expansion valve (13) and then flows into the evaporator (14). In the evaporator (14), the refrigerant absorbs heat from the internal air and evaporates. As a result, the inside of the container is cooled. The refrigerant evaporated in the evaporator (14) passes through the suction proportional valve (35) and is then sucked into the compressor (11).

<Energy saving operation mode>
Next, the energy saving operation mode of the refrigeration apparatus (1) will be described. The energy saving operation mode is controlled by the energy saving operation control section (52). Specifically, in this energy saving operation mode, the control operations from the first operation to the third operation as shown in FIGS. 6 and 7 are performed by the control units (53, 54, 55) of the energy saving operation control unit (52). Repeatedly. Note that the basic refrigerant flow of the refrigeration apparatus (1) in the energy saving operation mode is the same as that in the normal operation mode described above.

    Further, in this energy saving operation mode, the first operation (FIG. 6) and the second operation (FIG. 7) having higher energy saving performance than the first operation can be switched according to the outside temperature and the user setting. . Specifically, the energy saving operation control unit (52), when set by the user, selects the first operation when the outside temperature is higher than the second lower limit temperature of the target range, and the outside temperature is within the target range. The second operation is selected when the temperature is equal to or lower than the second lower limit temperature.

    First, the first operation shown in FIG. 6 will be described. In the first operation, the automatic ventilation port (7) is maintained in the closed state.

    The first operation of the first operation is performed by the first control unit (53). In this first operation, the compressor (11) is operated and the internal fan (16) is operated at a normal rotational speed. Although not shown, the external fan (15) is operated at a normal rotational speed. . Further, during the first operation, the cooling capacity of the evaporator (14) is adjusted so that the internal temperature becomes the target temperature.

    Specifically, during the first operation, the opening degree of the suction proportional valve (35) is adjusted by PI control based on the target temperature and the temperature detected by the internal temperature sensor. As a result, the refrigerant circulation amount of the refrigerant circuit (10) is adjusted according to the opening of the suction proportional valve (35), and the cooling capacity of the evaporator (14) is adjusted.

    In addition, when the cooling capacity of the evaporator (14) is adjusted while the opening degree of the suction proportional valve (35) is reduced in this way, the refrigerant easily becomes wet throughout the entire area of the evaporator (14). For this reason, if the cooling capacity of the evaporator is adjusted by adjusting the opening of the electronic expansion valve on the inflow side of the evaporator, the refrigerant flowing through the evaporator becomes dry and flows from the inflow end to the outflow end of the evaporator. However, if the cooling capacity of the evaporator (14) is adjusted while reducing the opening of the suction proportional valve (35) as in this embodiment, the refrigerant (14) The temperature distribution of the refrigerant from the inflow end to the outflow end is made uniform. As a result, the internal air is cooled relatively uniformly, and the controllability of the internal temperature by the evaporator (14) is improved.

    After the first operation, the second operation by the second control unit (54) is performed. In the present embodiment, when the set time set in the controller (50) elapses from the first operation start time t0, the first operation is shifted to the second operation. This set time is set to a time interval sufficient to maintain the internal temperature at the target temperature by cooling the evaporator (14). In this embodiment, this set time is set to about 2 minutes. Yes. That is, in the energy saving operation mode, when the time t1 at which two minutes have elapsed from the time t0 and it is determined that the internal temperature is reliably maintained at the target temperature is reached, the control operation (the first control portion (53)) 1 operation) to the control operation (second operation) of the second control unit (54).

    In the second operation, after the time t1, the cooling capacity of the evaporator (14) is gradually increased, and the internal temperature decreases. Specifically, in the second operation, the compressor (11) is continuously operated, and the internal fan (16) and the external fan (15) are also operated at a normal rotation speed. On the other hand, during the second operation, the opening degree of the suction proportional valve (35) is gradually adjusted after time t1. As a result, the refrigerant circulation amount in the refrigerant circuit (10) gradually increases, and the cooling capacity of the evaporator (14) also gradually increases.

    When the internal temperature decreases to the first lower limit temperature by adjusting the opening degree of the suction proportional valve (35), the compressor (11) is stopped and the internal fan (16) is lower than the normal rotation speed. The rotation speed is reached (time t2). That is, in the second operation, when the internal temperature is lowered to the first lower limit temperature (predetermined temperature according to the present invention) by increasing the cooling capacity of the evaporator (14), the compressor (11) is stopped and the internal temperature is reduced. Operate the internal fan (16) with low airflow. The opening degree adjustment of the suction proportional valve (35) during the second operation is performed stepwise so that the opening degree increases by 10% every 10 seconds from time t1. As a result, the internal temperature drops relatively slowly, so that the occurrence of so-called undershoot in which the internal temperature falls below the first lower limit temperature in the second operation is suppressed.

    In the second operation, when the compressor (11) is stopped, the refrigeration cycle in the refrigerant circuit (10) is stopped, and the cooling of the interior by the evaporator (14) is substantially stopped. For this reason, the internal temperature gradually increases. However, since the compressor (11) is stopped and the internal fan (16) has a lower rotational speed than the normal rotational speed, that is, the rotational speed of the internal fan (16) is lower than that during the first operation. Therefore, the amount of heat generated by the operation of the motor of the internal fan (16) is suppressed. Therefore, the rising speed of the internal temperature during the second operation is reduced. In this second operation, the opening degree of the suction proportional valve (35) is maintained at the opening degree when the internal temperature is lowered to the first lower limit temperature (time t2). Further, after the time t2 in the second operation, although not shown, the outside fan (15) is stopped.

    Then, in the second operation, when the internal temperature gradually increases and reaches the upper limit temperature, the third operation by the third control unit (55) is performed (time t4). By the third operation, the compressor (11) is operated again and the internal fan (16) is operated at the normal rotation speed, and the first operation by the first control unit (53) is resumed. That is, the first operation is resumed from time t4 when the internal temperature reaches the upper limit temperature. The suction proportional valve (35) has the opening degree maintained during the second operation as the initial opening degree of the first operation, and thereafter the opening degree is adjusted by PI control based on the target temperature and the temperature detected by the internal temperature sensor. The For this reason, the opening degree of the suction proportional valve (35) at the start of the first operation is the same as the opening degree in which the cooling capacity of the evaporator (14) is increased and the internal air is cooled in the second operation. . As a result, the refrigerant circulation amount is secured from the start of the first operation in which the internal temperature reaches the upper limit temperature and the compressor (11) is restarted, the internal air is quickly cooled, and the internal temperature is set to the target temperature again. It converges to temperature.

    Next, the second operation shown in FIG. 7 will be described. In the second operation, in addition to the control during the first operation, open / close control of the automatic ventilation port (7) is performed.

    The first operation of the second operation is performed by the first control unit (53). In the first operation, the same control as the first operation in the first operation is performed. Subsequently, after time t1, the second operation by the second control unit (54) is performed, and similarly to the first operation, the cooling capacity of the evaporator (14) is gradually increased and the internal temperature decreases. To go.

    Specifically, in the second operation, the compressor (11) is continuously operated, and the internal fan (16) and the external fan (15) are also operated at a normal rotation speed. On the other hand, during the second operation, the opening degree of the suction proportional valve (35) is gradually adjusted after time t1. As a result, the refrigerant circulation amount in the refrigerant circuit (10) gradually increases, and the cooling capacity of the evaporator (14) also gradually increases.

    When the internal temperature drops to the second lower limit temperature by adjusting the opening degree of the intake proportional valve (35), the compressor (11) is stopped and the internal fan (16) is driven at a normal rotational speed. And the automatic ventilation port (7) is opened (time t2). That is, in the second operation of the second operation, the cooling capacity of the evaporator (14) is increased, and the internal temperature is lowered to the second lower limit temperature (predetermined temperature according to the present invention) higher than the first lower limit temperature. Therefore, as compared with the first operation, the time from the time t1 to the time t2 in the second operation is shortened by the amount that the internal temperature is reduced.

    In the second operation, when the compressor (11) is stopped, the cooling of the interior by the evaporator (14) is substantially stopped as in the first operation. However, in this second operation, the automatic ventilation port (7) is open, so the outside air is introduced into the chamber through the intake port (7a) of the automatic ventilation port (7), and the indoor air is automatically ventilated. It is discharged from the outlet (7b) of the mouth (7). Since the outside air introduced into the warehouse is below the inside temperature, the inside of the warehouse is cooled by the outside air. Therefore, unlike the first operation, the internal temperature further decreases from the second lower limit temperature. Here, since the internal fan (16) rotates at a lower speed than during the first operation, and the amount of heat generated by the motor is suppressed, the internal temperature is more likely to decrease. Then, the internal temperature rises after decreasing to the first lower limit temperature. Here, the amount of heat generated by the motor of the internal fan (16) is suppressed, and further, the amount of outside air being introduced into the internal space, the internal temperature rise rate is significantly reduced.

    In the second operation, when the internal temperature further rises and exceeds the second lower limit temperature, the internal fan (16) is stopped (time t3). Thereby, the heat generated by the motor of the internal fan (16) is eliminated, and the rate of increase of the internal temperature is further reduced.

    Then, in the second operation, when the internal temperature further rises and reaches the upper limit temperature, the third operation by the third control unit (55) is performed (time t4). By the third operation, the compressor (11) is operated again and the internal fan (16) is operated at a normal rotational speed, and the automatic ventilation port (7) is closed, and the first control unit (53) The first operation is resumed. That is, the first operation is resumed from time t4 when the internal temperature reaches the upper limit temperature. Further, as in the first operation, the suction proportional valve (35) uses the opening degree held during the second operation as the initial opening degree of the first operation, and thereafter, based on the target temperature and the temperature detected by the internal temperature sensor. The opening degree is adjusted by PI control.

    Thus, in the second operation of the second operation, the speed at which the internal temperature rises from the first lower limit temperature to the upper limit temperature is significantly slower than that in the first operation. Therefore, the time from the time t2 to the time t4 in the second operation becomes long. In this second operation, the opening degree of the suction proportional valve (35) is maintained at the opening degree when the internal temperature is lowered to the second lower limit temperature (time t2). Further, after the time t2 in the second operation, although not shown, the outside fan (15) is stopped.

<Automatic switching control between normal operation and energy-saving operation>
In the refrigeration apparatus (1) of the present embodiment, the normal operation mode and the energy saving operation mode described above are automatically switched as follows by the operation switching unit (56).

    As shown in FIG. 8, first, when normal operation (operation in the normal operation mode) is performed, in step S1, the suction temperature RT detected by the suction temperature sensor (RS) is compared with the target temperature in the cabinet. Is called. Here, when the suction temperature RT is outside the range of the target temperature ± 3.0 ° C., it is necessary to quickly bring the inside temperature into the target temperature range, and therefore normal operation is continued. On the other hand, if the suction temperature RT is within the target temperature ± 3.0 ° C., the internal temperature is already maintained within the target temperature range, and the need to continuously operate the compressor (11) is eliminated. Then, the process proceeds to step S2 to perform the energy saving operation (the first operation or the second operation in the energy saving operation mode).

    In the subsequent energy saving operation, the time required for one cycle from the start of the first operation to the end of the third operation is measured. In step S3, the time required for one cycle is compared with a preset time (for example, 180 seconds).

    By the way, when the outside temperature is extremely high, if the compressor (11) is stopped in the second operation, the time until the inside temperature shown in FIGS. 6 and 7 reaches the upper limit temperature (from time t2 to time t4). The time required for one cycle in energy saving operation is also shortened. Therefore, if the energy saving operation is continued under such conditions, the frequency of the compressor (11) is increased and the life of the compressor (11) is shortened. For this reason, in step S3, when the outside temperature is remarkably high and the time required for one cycle is equal to or shorter than the set time, the energy saving operation is terminated (step S4), and the normal operation is resumed (step S5). As a result, since the compressor (11) is in a continuous operation state, the life of the compressor (11) can be extended.

    In step S5, normal operation is started, and at this time, the outside temperature OT1 is measured by the outside temperature sensor (OS). Thereafter, in step S6, the current outside temperature OT2 is appropriately measured immediately after the start of normal operation. When the current outside temperature OT2 becomes lower than the outside temperature OT1 at the start of normal operation by a predetermined set temperature (for example, 5 ° C.) or more, the outside temperature is 5 than that at the end of the previous energy saving operation. Since the temperature has decreased by more than 0 ° C. and it is considered that the energy saving operation may be resumed, the process returns to step S1 and the start determination of the energy saving operation is performed again. On the other hand, if the current outside temperature OT2 is not lower than the outside temperature OT1 at the start of normal operation by a predetermined temperature or more, it is still considered that the outside temperature is high and the energy saving operation is not suitable, and the process proceeds to step S1. do not do.

    In the refrigeration apparatus (1), the above-described defrost operation is performed periodically (for example, every 4 hours) regardless of each operation mode. For this reason, after the end of the defrost operation, the normal operation is performed and the start determination of the energy saving operation in step S1 is performed.

<Prohibition control of energy-saving operation>
Further, in the refrigeration apparatus (1) of the present embodiment, when the cumulative number of starts / stops of the compressor (11) exceeds a predetermined set number by the energy saving operation as described above, only normal operation (operation in the normal operation mode) is performed. Is allowed, and energy-saving operation (operation in the energy-saving operation mode) is prohibited. Specifically, in the refrigeration apparatus (1), the number of ON / OFF times of the magnet switch that performs start / stop control of the compressor (11) is gradually counted. In this case, the count is performed by setting the number of times the magnet switch is switched from OFF to ON as one start / stop number. On the other hand, a predetermined upper limit number (for example, 200,000 times) is set in the controller (50) according to the specifications of the compressor (11). When the number of starts and stops of the compressor (11) exceeds 200,000 due to the above-described energy saving operation or the like, the energy saving operation is prohibited and only normal operation can be performed.

-Effect of the embodiment-
In the present embodiment, the following effects are exhibited.

    In the present embodiment, in the second operation in the energy saving operation mode, not only the compressor (11) is intermittently operated, but also the outside air that is lower than the internal temperature is stored while the compressor (11) is stopped. Introduced inside. Therefore, compared with the case where only a stop of a compressor (11) is performed, the raise rate of internal temperature can be slowed. Thereby, the time until the internal temperature reaches the upper limit temperature (the time from the time t2 to the time t4 in the second operation), that is, the stop time of the compressor (11) can be extended. Therefore, the driving power of the compressor (11) can be reduced as compared with the conventional case, and the energy saving performance can be improved.

    Further, in the second operation of the energy saving operation mode of the present embodiment, the low temperature outside air is introduced into the warehouse using the automatic ventilation port (7) provided for the purpose of ventilating the inside of the warehouse. I made it. Therefore, it is not necessary to newly provide outside air introduction means for introducing outside air into the warehouse. As a result, the refrigeration apparatus (1) can be made compact and cost can be reduced.

    In addition, the automatic ventilation port (7) is not frequently used for the purpose of ventilating the inside of the cabinet. Therefore, the automatic ventilation port (7) can be effectively utilized by using the automatic ventilation port (7) as the outside air introducing means as in the present embodiment.

    In the second operation in the energy saving operation mode, the compressor (11) is stopped after being lowered to the second lower limit temperature higher than the first lower limit temperature by the second operation. That is, the reduction width of the internal temperature is smaller than that in the first operation. For this reason, the time of the second operation can be shortened compared to the first operation. Thereby, the operation time of the compressor (11) in 2nd operation | movement can be shortened, and energy saving property improves further.

    Thus, in the second operation of the second operation, the internal temperature is lowered only to the second lower limit temperature. However, in the second operation, since the outside air is introduced into the warehouse in the second operation, the inside temperature can be lowered to the first lower limit temperature while the compressor (11) is stopped. Therefore, it is possible to lengthen the time for the internal temperature to reach the upper limit temperature in the second operation. As a result, since the stop time of the compressor (11) in the second operation can be extended, the energy saving performance is improved.

    Further, in the energy saving operation mode, the internal temperature transitions between the first lower limit temperature that is the lower limit value of the allowable temperature range of the internal temperature and the upper limit temperature that is the upper limit value of the allowable temperature range. The capacity control of the evaporator (14) and the start / stop control of the compressor (11) are performed. For this reason, in the energy saving operation mode, it can be avoided that the internal temperature is out of the allowable temperature range, and the reliability of the refrigeration apparatus (1) can be improved.

    Furthermore, in the above-described embodiment, the internal fan (16) is operated at a lower rotational speed during the second operation than during the first operation. For this reason, during the second operation, the amount of heat generated by driving the motor of the internal fan (16) can be suppressed, so the time until the internal temperature reaches the upper limit temperature after the compressor (11) is stopped. Can be prolonged. Therefore, the stop time of the compressor (11) can be extended, and the energy saving performance of the refrigeration apparatus (1) can be further improved.

    Further, in the second operation of the second operation, the internal fan (16) is stopped when the internal temperature rises to some extent (up to the second lower limit temperature). As a result, the amount of heat generated by the motor of the internal fan (16) can be eliminated, and the duration of the second operation can be prolonged. Therefore, the energy saving performance of the refrigeration apparatus (1) can be further improved.

    In this embodiment, the cooling capacity of the evaporator (14) is adjusted by adjusting the opening of the suction proportional valve (35). When the cooling capacity of the evaporator (14) is adjusted while adjusting the opening of the suction proportional valve (35) in this way, the refrigerant becomes moist throughout the evaporator (14). Thus, the air in the cabinet can be cooled relatively uniformly. As a result, in the first operation in the energy saving operation mode, the internal temperature can be quickly and reliably brought close to the target temperature.

    In the second operation, the operating capacity of the compressor (11) does not change even when the opening of the proportional proportional valve (35) is adjusted to increase the cooling capacity of the evaporator (14). Thus, the cooling capacity of the evaporator (14) can be increased without increasing the operating power of the compressor (11) during the second operation. Therefore, the energy saving performance of the refrigeration apparatus (1) can be further improved.

    Moreover, in the said embodiment, based on the suction | inhalation temperature RT of the air in the store | warehouse | chamber before flowing in into a cooling heat exchanger (14), the transition determination from normal operation mode to energy saving operation mode is performed. The normal operation is continued until the suction temperature RT falls within the target temperature range. Here, the suction temperature RT is the temperature of the air in the cabinet before being cooled by the cooling heat exchanger (14), and thus is close to the actual temperature in the cabinet. For this reason, when the transition determination from the normal operation to the energy saving operation is performed based on the suction temperature RT, the actual internal temperature can be quickly brought into the target temperature range and then the energy saving operation can be performed. Therefore, since the conveyed item in the warehouse can be reliably cooled within the target temperature range, the refrigeration apparatus (1) can be operated with an emphasis on the quality of the conveyed item.

    On the other hand, in the above embodiment, when the time required for one cycle of the energy saving operation is shorter than the predetermined set time, the operation is automatically shifted to the normal operation. That is, in the above-described embodiment, when the number of starts and stops of the compressor (11) in the energy saving operation becomes high, the energy saving operation is shifted to the normal operation. Therefore, the number of start / stop times of the compressor (11) can be reduced, and the life of the compressor (11) can be extended.

-Modification of the embodiment-
<Modification 1>
In the energy saving operation mode of the above embodiment, the automatic ventilation port (7) is opened at a constant opening degree (fully opened or predetermined opening degree) in the second operation. The degree of opening of the automatic ventilation port (7) may be adjusted stepwise in accordance with the slope.

    Specifically, as shown in FIG. 9, in the second operation, when the internal temperature is lowered to the second lower limit temperature, the automatic ventilation port (7) is first fully opened (opening degree 100%), and thereafter The opening degree of the automatic ventilation port (7) decreases stepwise (for example, by 10%). Then, after the opening degree reaches a predetermined value (for example, 70%), the opening degree is increased stepwise (for example, by 10%) and finally fully opened. In the opening degree control of the automatic ventilation port (7), the amount of decrease in the opening degree increases or the time interval for reduction decreases as the degree of decrease in the internal temperature (gradient of decrease) increases. That is, in this control, when the internal temperature rapidly decreases by opening the automatic ventilation port (7), the amount of outside air introduced is reduced. By doing so, it is possible to suppress a rapid decrease in the internal temperature. As a result, it is possible to reliably prevent so-called undershoot in which the internal temperature is lower than the first lower limit temperature. Moreover, in this control, in order to reduce the opening degree of an automatic ventilation port (7) in steps, it is the state which falls below 1st minimum temperature, reducing the inside temperature toward 1st minimum temperature reliably. Can be avoided.

<Modification 2>
In the energy saving operation mode of the above-described embodiment, the automatic ventilation port (7) is opened at a constant opening (fully opened or predetermined opening) in the second operation. Hereinafter, the opening degree of the automatic ventilation port (7) may be adjusted so that the CO2 concentration becomes the set concentration.

    Specifically, in the second operation of the second operation in the energy saving operation mode, the opening degree of the automatic ventilation port (7) is adjusted by the second control unit (54) as shown in FIGS. First, in step ST1, it is determined whether the setting with control of carbon dioxide (CO2) is set by the user. If carbon dioxide (CO2) control is set, it is determined in step ST2 whether or not the compressor (11) is stopped. That is, in the second operation, it is determined whether the internal temperature is lowered to the second lower limit temperature and the compressor (11) is stopped. When the compressor (11) is stopped, as described above, the internal fan (16) is operated at a low rotational speed and the automatic ventilation port (7) is fully opened (steps ST3 and ST4). By opening the automatic ventilation port (7), the air in the cabinet is discharged and the CO2 concentration in the cabinet decreases. In subsequent step ST5, a measurement timer (not shown) is started, and at the same time, the detected concentration is input from the gas concentration sensor (GS) to the second control unit (54). That is, the CO2 concentration in the warehouse when the automatic ventilation port (7) is fully opened is stored in the second control unit (54). Subsequently, in step ST6, it is determined whether the CO2 concentration in the storage has become 0%.

    When the CO2 concentration in the chamber becomes 0%, the process proceeds to step ST7, and the CO2 concentration descending gradient Gd (hereinafter referred to as descending gradient Gd) when the automatic vent (7) is fully opened is calculated. This descending gradient Gd is a descending amount per unit time of the CO2 concentration in the warehouse when the automatic ventilation port (7) is fully opened. Specifically, the second control unit (54) measures the time from when the automatic ventilation port (7) is fully opened until the CO2 concentration in the warehouse reaches 0% by the measuring timer, and inputs the time. Is done. And the 2nd control part (54) calculates descending gradient Gd from the input time and the CO2 density | concentration in the store | warehouse | chamber when the automatic ventilation port (7) input by step ST5 is fully opened. .

    Subsequently, in step ST8, the automatic ventilation port (7) is closed. When the automatic vent (7) is closed, carbon dioxide accumulates in the warehouse due to the ripening of the fruits and vegetables that are being transported. That is, the CO2 concentration in the storage increases. When a predetermined time ta elapses after the automatic ventilation port (7) is closed (step ST9), the process proceeds to step ST10, and the CO2 concentration rising gradient Gu (hereinafter referred to as the rising gradient Gu) when the automatic ventilation port (7) is closed. Is calculated). This ascending gradient Gu is the amount of increase per unit time of the CO2 concentration in the warehouse when the automatic vent (7) is closed. Specifically, the second control unit (54) receives the CO2 concentration in the cabinet when a predetermined time ta has elapsed since the automatic ventilation port (7) was closed. Then, the second control unit (54) calculates the rising gradient Gu from the inputted CO2 concentration and the predetermined time ta.

    Subsequently, the second control unit (54) calculates an appropriate opening degree D of the automatic ventilation port (7) based on the calculated descending gradient Gd and ascending gradient Gu (step ST11). The appropriate opening degree D includes an amount in which the CO2 concentration in the warehouse decreases per unit time due to ventilation by the automatic vent (7), and an amount in which the CO2 concentration in the warehouse increases per unit time due to ripening of fruits and vegetables. It is the opening of the automatic ventilation port (7) which becomes equivalent. That is, the opening degree of automatic ventilation in which the amount of carbon dioxide that decreases per unit time due to ventilation is equal to the amount of carbon dioxide that increases per unit time due to ripening of fruits and vegetables.

    When the appropriate opening degree D of the automatic ventilation port (7) is calculated, the second control unit (54) adjusts the opening degree of the automatic ventilation port (7) so that the CO2 concentration in the warehouse becomes the set concentration ( Step ST12). For example, when the CO2 concentration in the chamber is higher than the set concentration, the opening degree of the automatic ventilation port (7) is increased, and when the CO2 concentration in the chamber is lower than the set concentration, the opening degree of the automatic ventilation port (7) Is reduced. And if the CO2 density | concentration in a store | warehouse | chamber becomes a setting density | concentration (step ST13), it will transfer to step ST14 and the opening degree of an automatic ventilation port (7) will be set to the appropriate opening degree D. FIG. In this state, the increase amount and the decrease amount per unit time of the CO2 concentration are equal, and the CO2 concentration in the storage is maintained at the set concentration.

    In the above state, the CO2 concentration may fluctuate for some reason. When the CO2 concentration increases and reaches the upper limit value of the set concentration (step ST15), the process proceeds to step ST16, and the automatic ventilation port (7) is fully opened. As a result, the amount of carbon dioxide emission increases in the warehouse, and the CO2 concentration decreases. When the automatic ventilation port (7) is fully opened, the process returns to step ST13 again to determine whether the CO2 concentration has reached the set concentration. Conversely, when the CO2 concentration decreases and reaches the lower limit value of the set concentration (step ST17), the process proceeds to step ST18, and the automatic ventilation port (7) is closed. As a result, the amount of carbon dioxide emission decreases and the CO2 concentration increases in the warehouse. When the automatic ventilation port (7) is closed, the process returns to step ST13 again to determine whether the CO2 concentration has reached the set concentration. In the second control unit (54), an upper limit value and a lower limit value of the set density, which is a target range, are set. Even if the CO2 concentration varies, if it is between the upper limit value and the lower limit value of the set concentration (steps ST15 and ST17), the process proceeds to step ST14 and the automatic ventilation port (7) is maintained at the appropriate opening degree D. .

    Thus, in this modification, in the second operation of the second operation in the energy saving operation mode, not only the automatic ventilation port (7) is opened, but also the CO2 concentration in the warehouse is automatically set to the set concentration. The opening of the ventilation opening (7) is adjusted. Therefore, in the second operation, the CO2 concentration in the warehouse can be maintained at an appropriate concentration for fruits and vegetables while introducing low-temperature outside air into the warehouse. As a result, it is possible to extend the stop time of the compressor (11) to improve the energy saving performance and to reliably maintain the freshness of the fruits and vegetables.

    Moreover, since the descending gradient Gd and the ascending gradient Gu are calculated and the appropriate opening degree D of the automatic ventilation port (7) is calculated based on these, the adjustment of the opening degree of the automatic ventilation port (7) is actually transported. It can be done appropriately according to the fruits and vegetables.

-Other control examples-
In the refrigeration apparatus (1) of the above embodiment, the following control may be performed.

    For example, in the energy saving operation mode of the above embodiment, the compressor (11) may be stopped and the internal fan (16) may be completely stopped in the second operation. In this case, the motor of the internal fan (16) does not generate heat, and the internal temperature increase in the second operation can be positively suppressed. Therefore, the stop time of the compressor (11) can be further prolonged, and the power consumption of the refrigeration apparatus (1) can be effectively reduced. Moreover, since the driving power of the internal fan (16) is also reduced, the energy saving performance of the refrigeration apparatus (1) is further improved.

    In the energy saving operation mode of the above embodiment, the internal temperature is lowered to the second lower limit temperature in the second operation of the second operation, but is lowered to the first lower limit temperature that is the lower limit value of the target range. It may be.

    Further, in the energy saving operation mode of the above embodiment, the internal fan (16) is stopped when the internal temperature exceeds the second lower limit temperature in the second operation of the second operation. 2 Even if the lower limit temperature is exceeded, the internal fan (16) may continue to operate at a low rotational speed.

    Further, in the energy saving operation mode of the above embodiment, the cooling capacity of the evaporator (14) is gradually increased by gradually increasing the opening of the suction proportional valve (35) during the second operation. Yes. However, immediately after the start of the second operation, the evaporator is controlled by controlling the suction proportional valve (35) to be twice the current opening degree or performing PI control based on the detection value of the internal temperature sensor with the first lower limit temperature as a target. The cooling capacity of (14) may be increased.

    Further, in the energy saving operation mode of the above embodiment, the opening held in the second operation of the suction proportional valve (35) is set as the initial opening of the first operation. However, in the first operation to be resumed, the opening degree of the suction proportional valve (35) is fixed as a predetermined opening degree regardless of the opening degree of the suction proportional valve (35) held in the second operation. Alternatively, for example, the opening degree of the suction proportional valve (35) may be adjusted according to the internal temperature.

    In the energy saving operation mode of the above embodiment, the suction proportional valve (35) is used as a capacity adjusting means for adjusting the cooling capacity of the evaporator (14). However, it is also possible to adjust the cooling capacity of the evaporator (14), for example, by adjusting the opening of the electronic expansion valve upstream of the evaporator (14) or adjusting the capacity of the compressor.

    Furthermore, in the said embodiment, it is made to judge transfer from a normal driving | operation to an energy-saving driving | operation based on the suction temperature of the air in a warehouse sent into an evaporator (14). However, when the blowout temperature of the internal air after passing through the cooling heat exchanger (14) is detected by the blowout temperature sensor (SS) and this blowout temperature falls within a predetermined set temperature range including the target temperature, You may make it transfer from a driving | operation to an energy-saving driving | operation. Since this blowing temperature is slightly lower than the suction temperature, in this case, the timing of transition from normal operation to energy-saving operation is earlier than in the above embodiment. That is, in this example, energy-saving operation is performed more frequently than in the above embodiment. Therefore, the refrigeration apparatus (1) of this example can be operated with an emphasis on energy saving.

    Further, in the above embodiment, in the energy saving operation mode, when the time required for one cycle from the start of the first operation to the end of the third operation exceeds a predetermined set time, the operation is shifted to the normal operation. However, during the energy saving operation, when the stop time of the compressor (11) in the second operation exceeds a predetermined set time, the operation may be shifted to the normal operation. Also in this case, the start / stop frequency of the compressor (11) can be reduced, and the life of the compressor (11) can be extended.

    In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

    As described above, the present invention is useful for an energy saving operation method of a refrigeration apparatus provided with a cooling heat exchanger for cooling the inside of a warehouse.

1 Refrigeration equipment
7 Automatic vent (outside air introduction means)
10 Refrigerant circuit
11 Compressor
14 Evaporator (cooling heat exchanger)
16 Inside fan
35 Suction proportional valve (capacity adjusting means, flow rate adjusting valve)
51 Normal operation controller
52 Energy-saving operation control unit
53 1st control part
54 Second controller
55 Third control unit
56 Operation switching section

Claims (10)

A refrigeration apparatus comprising a refrigerant circuit (10) connected to a cooling heat exchanger (14) and a compressor (11) for cooling the inside of the refrigerator and performing a refrigeration cycle through circulation of the refrigerant,
While comprising a capacity adjusting means (35) for adjusting the cooling capacity of the cooling heat exchanger (14) so that the inside temperature becomes the target temperature, and an outside air introducing means (7) for introducing outside air into the inside,
A first controller (53) for operating the compressor (11) while adjusting the cooling capacity of the cooling heat exchanger (14) by the capacity adjusting means (35);
When the internal temperature is maintained at the target temperature during the control operation by the first control unit (53), the cooling capacity of the cooling heat exchanger (14) is increased by the capacity adjusting means (35) to increase the target temperature. After lowering the internal temperature to a predetermined temperature that is equal to or higher than the lower limit value of the target range including the above and below the target temperature, the compressor (11) is stopped, and the external temperature is equal to or lower than the internal temperature A second control unit (54) for introducing outside air into the cabinet by outside air introducing means (7);
When the inside temperature reaches the upper limit of the target range during the control operation by the second control unit (54), the compressor (11) is started and the introduction of outside air by the outside air introducing means (7) is prohibited. And a third control unit (55) for resuming the control operation by the first control unit (53). In claim 1,
The outside air introduction means is an openable / closable vent (7) for ventilating the inside of the cabinet,
The second control unit (54) stops the compressor (11) and, when the outside temperature is not more than the inside temperature, opens the ventilation port (7) and introduces outside air into the inside. While letting
The third control unit (55) activates the compressor (11) and closes the ventilation port (7) to prohibit the introduction of outside air. In claim 1 or 2,
An internal fan (16) that blows the internal air to the cooling heat exchanger (14) and blows it out again is provided.
The second control unit (54) reduces the operating speed of the internal fan (16) after lowering the internal temperature to the predetermined temperature,
The refrigeration apparatus, wherein the third control unit (55) increases the operating rotational speed of the internal fan (16) when the internal temperature reaches an upper limit value of the target range. In claim 1 or 2,
An internal fan (16) that blows the internal air to the cooling heat exchanger (14) and blows it out again is provided.
The second controller (54), after lowering the internal temperature to the predetermined temperature, stops the internal fan (16),
The said 3rd control part (55) starts the said internal fan (16), when the internal temperature reaches the upper limit of the said target range, The freezing apparatus characterized by the above-mentioned. In claim 1 or 2,
An internal fan (16) that blows the internal air to the cooling heat exchanger (14) and blows it out again is provided.
The second control unit (54) sets the predetermined temperature to a temperature higher than the lower limit value of the target range, reduces the internal temperature to the predetermined temperature, and then operates the internal fan (16) to rotate. The number is decreased, and then the internal fan (16) is stopped when the internal temperature exceeds the predetermined temperature,
The said 3rd control part (55) starts the said internal fan (16), when the internal temperature reaches the upper limit of the said target range, The freezing apparatus characterized by the above-mentioned. In claim 1 or 2,
The capacity adjusting means includes a flow rate adjusting valve (35) that is connected to the refrigerant circuit (10) and adjusts the flow rate of the refrigerant sucked into the compressor (11).
The second control unit (54) increases the cooling capacity of the cooling heat exchanger (14) by increasing the opening of the flow rate adjusting valve (35). In claim 6,
The second control unit (54) lowers the internal temperature to the predetermined temperature, and then the flow rate adjusting valve until the third control unit (55) restarts the control operation of the first control unit (53). The refrigeration apparatus characterized in that the opening degree of (35) is maintained at the opening degree when the inside temperature is lowered. In any one of Claims 1 thru | or 7,
A normal operation control unit (51) for continuously operating the compressor (11) while adjusting the cooling capacity of the cooling heat exchanger (14) by the capacity adjusting means (35), and the first control unit (53 ), An energy saving operation control unit (52) composed of the second control unit (54) and the third control unit (55),
Suction temperature sensor (RS) that detects the temperature of the internal air sent to the cooling heat exchanger (14), and the temperature detected by the suction temperature sensor (RS) during the control operation by the normal operation control unit (51) A refrigeration apparatus comprising: an operation switching unit (56) for switching to a control operation by the energy saving operation control unit (52) when the temperature falls within a predetermined temperature range including the target temperature. In any one of Claims 1 thru | or 7,
A normal operation control unit (51) for continuously operating the compressor (11) while adjusting the cooling capacity of the cooling heat exchanger (14) by the capacity adjusting means (35), and the first control unit (53 ), An energy saving operation control unit (52) composed of the second control unit (54) and the third control unit (55),
A blowout temperature sensor (SS) that detects the temperature of the air in the compartment that passes through the cooling heat exchanger (14) and blows out into the compartment, and the blowout temperature sensor (51) during the control operation by the normal operation control unit (51) A refrigeration apparatus comprising: an operation switching unit (56) for switching to a control operation by the energy saving operation control unit (52) when a detected temperature of SS) falls within a predetermined temperature range including the target temperature. In any one of Claims 2 thru | or 9,
While equipped with a gas concentration sensor (GS) that detects the concentration of carbon dioxide in the chamber,
The second control unit (54) adjusts the opening degree of the ventilation port (7) so that the detected concentration of the gas concentration sensor (GS) becomes a set concentration after the inside temperature is lowered to the predetermined temperature. A refrigeration apparatus characterized by:

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