JP2013029295A - Container refrigeration unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container refrigeration unit allowing a temperature of air to be blown into a chamber to be properly controlled.SOLUTION: The container refrigeration unit (10) includes a refrigerant circuit (16) and a reheater (32), and performs dehumidifying operation, which heats, in the reheater (32), the air sucked from inside of the chamber of a container (C) and cooled and dehumidified in an evaporator (25). The container refrigeration unit includes: a suction temperature sensor (33) detecting the temperature of the air sucked into the evaporator (25); a blow-off temperature sensor (34) detecting the temperature of the air heated by the reheater (32); a temperature control unit (36) controlling the dehumidification operation on the basis of the value of the detected temperature of the blow-off temperature sensor (34); and a temperature correction unit (37) correcting a value of the detected temperature of the blow-off temperature sensor (34) to be lower than the detected temperature of the suction temperature sensor (33) when the detected temperature of the suction temperature sensor (33) lowers below the detected temperature of the blow-off temperature sensor (34) in the dehumidification operation.

Description

    The present invention relates to a container refrigeration apparatus, and particularly relates to blowout temperature control during a dehumidifying operation.

    Conventionally, a container refrigeration apparatus is used to cool the inside of a container used for marine transportation or the like.

    The container refrigeration apparatus disclosed in Patent Document 1 includes a refrigerant circuit to which a compressor, a condenser, a receiver, an electronic expansion valve, and an evaporator are sequentially connected. The refrigerant circuit is provided with a heat exchanger for heating located on the leeward side of the evaporator. This heat exchanger is configured so that the discharge gas refrigerant of the compressor flows. In the container refrigeration apparatus, a dehumidifying operation is performed in which air (blowing air) cooled and dehumidified in the evaporator is heated by the heat exchanger for heating.

Japanese Patent Laid-Open No. 11-63769

    By the way, in the container refrigeration apparatus as described above, the blown air is blown out from the blowout port extending in the width direction of the warehouse. And the temperature control in a store | warehouse | chamber is performed based on the detected temperature of the blowing air detected by the temperature sensor provided in one place in the said blower outlet.

    However, if the blown air blown from the evaporator is heated by the heating heat exchanger during the dehumidifying operation, temperature unevenness occurs in the blown air in the interior width direction. That is, even if the temperature detected by the temperature sensor is close to the internal temperature, the average temperature of the blown air may be low. In this case, when temperature control is performed based on the temperature detected by the temperature sensor, on average, air having a temperature lower than the temperature detected by the temperature sensor is blown out. As a result, there is a problem that the load causes a low-temperature failure. .

    This invention is made | formed in view of such a point, and it aims at controlling the temperature of the air blown off in a store | warehouse | chamber to appropriate temperature.

    The first invention includes a refrigerant circuit (16) in which a compressor (21), a condenser (23), an expansion mechanism (76), and an evaporator (25) are connected in order, and the evaporator (25 A heater (32) that heats the air that has flowed out from the container chamber, and performs a dehumidifying operation that heats the air that has been sucked from the container chamber and cooled and dehumidified in the evaporator (25) in the heater (32). A container refrigeration apparatus for detecting the temperature of air sucked into the evaporator (25), and a blower for detecting the temperature of air heated by the heater (32) A temperature detector (34); a temperature control unit (36) for controlling the dehumidifying operation based on a detected temperature value of the blowing temperature detector (34); and the suction temperature detector (33) in the dehumidifying operation. If the detected temperature is lower than the detected temperature of the outlet temperature detector (34), the A temperature correction unit (37) for correcting the detected temperature value of the outlet temperature detector (34) to be lower than the detected temperature of the suction temperature detector (33) is provided.

    In the first aspect of the invention, in the refrigerant circuit (16), the refrigerant discharged from the compressor (21) is condensed by the condenser (23), then expanded by the expansion mechanism (76), and then expanded by the evaporator (25). Evaporate. In the evaporator (25), heat is exchanged between the refrigerant and the internal air of the container (C), and the internal air is cooled. The suction temperature detector (33) detects the temperature of the suction air of the evaporator (25). The blowing temperature detector (34) detects the temperature of the air blown from the heater (32).

    Further, in the container refrigeration apparatus according to the present invention, a dehumidifying operation is performed in which the air cooled and dehumidified by the evaporator (25) is heated by the heater (32). The temperature controller (36) controls the dehumidifying operation based on the value of the detected temperature of the blowing temperature detector (34). When the temperature detected by the suction temperature detector (33) is lower than the temperature detected by the blowout temperature detector (34) in the dehumidifying operation, the temperature correction unit (37) detects the value of the temperature detected by the blowout temperature detector (34). Is corrected to be lower than the detected temperature of the suction temperature detector (33). In this case, the temperature control unit (36) controls the dehumidification operation based on the detected temperature value corrected to be low, and therefore performs the control while suppressing the cooling capacity. For this reason, even if the temperature unevenness of the blown air occurs in the interior width direction, the blown temperature rises as a whole. Thereby, the low-temperature failure to the cargo in a warehouse can be prevented reliably.

    According to a second aspect of the present invention, in the first aspect, the temperature correction unit (37) again performs the suction temperature detector (33) in the dehumidifying operation after correcting the detection temperature of the outlet temperature detector (34). ) Detected temperature is lower than the detected temperature of the outlet temperature detector (34), the detected temperature value of the outlet temperature detector (34) is set to be lower than the detected temperature of the inlet temperature detector (33). It is configured to correct low.

    In the second aspect of the invention, the temperature correction unit (37), when the detection temperature of the suction temperature detector (33) is lower than the detection temperature of the blowing temperature detector (34) in the dehumidifying operation, 34) Correct the detected temperature value lower than the detected temperature of the suction temperature detector (33). Thereafter, when the detected temperature of the suction temperature detector (33) becomes lower than the detected temperature of the blowout temperature detector (34), the value of the detected temperature of the blowout temperature detector (34) is again set to the suction temperature detector. Correct the temperature below the detected temperature in (33). Thus, the low temperature failure can be surely prevented by repeating the correction of the blowing temperature.

    According to a third aspect of the present invention, in the first or second aspect, the temperature correction unit (37) detects the blowing temperature detector (34) and the suction temperature detector (33) before the dehumidifying operation. The correction amount of the detected temperature value of the blowing temperature detector (34) is reduced as the temperature difference increases, while the correction amount is increased as the detected temperature difference decreases. ing.

    In the said 3rd invention, the temperature correction | amendment part (37) has a big difference (detection temperature difference) with the detection temperature of a blowing temperature detector (34) and the detection temperature of a suction temperature detector (33) before dehumidification operation | movement. Then, the correction amount of the detected temperature value of the blowing temperature detector (34) is reduced. That is, if the detected temperature difference between the blown air and the intake air is large, it is presumed that the refrigeration load of the internal air is high, so it is necessary to ensure the internal cooling capacity. For this reason, the temperature correction unit (37) suppresses the correction amount in order to ensure the cooling capacity.

    When the temperature correction unit (37) suppresses the correction amount, the detected temperature of the blowing temperature detector (34) is corrected to be higher. And since a temperature control part (36) controls dehumidification operation | movement based on the value of the detected temperature corrected highly, a cooling capability becomes large. For this reason, in the state where the freezing load in a warehouse is large, cooling capacity does not run short.

    On the other hand, if the difference (detection temperature difference) between the detection temperature of the blowing temperature detector (34) and the detection temperature of the suction temperature detector (33) becomes small before the dehumidifying operation, the temperature correction unit (37) detects the blowing temperature. Increase the correction amount of the detected temperature value of the vessel (34). That is, if the detected temperature difference between the blown air and the intake air is small, it is estimated that the refrigeration load of the internal air is small, so the cooling capacity in the internal space is suppressed. For this reason, in the temperature correction unit (37), the correction amount is increased in order to suppress the cooling capacity.

    When the temperature correction unit (37) increases the correction amount, the detection temperature of the blowing temperature detector (34) is corrected to be lower. And since a temperature control part (36) controls dehumidification operation | movement based on the value of the detected temperature correct | amended rather low, cooling capacity is suppressed. For this reason, in the state where the refrigeration load in a store | warehouse | chamber is small, even if the temperature nonuniformity of the blowing air has arisen in the width direction of a store | warehouse | chamber, this blowing temperature rises as a whole. Thereby, the low-temperature failure to the cargo in a warehouse can be prevented reliably.

    According to the first aspect of the invention, when the detected temperature of the blown air and the detected temperature of the intake air are reversed, the value of the detected temperature of the blown air is corrected to be low, so that the cooling capacity during the dehumidifying operation can be suppressed. it can. For this reason, the temperature of the air blown out into the warehouse can be raised as a whole. Thereby, even if the temperature nonuniformity of the blowing air has arisen in the width direction of a store | warehouse | chamber, the low temperature disorder | damage | failure to the load in a store | warehouse | chamber can be prevented reliably.

    According to the second aspect of the present invention, after the correction once, when the detected temperature of the blown air and the intake air is reversed again, the value of the detected temperature of the blown air is corrected again so that the cargo in the warehouse can be more reliably transferred. Can prevent the low temperature failure.

    Here, when the cooling capacity is suppressed to a predetermined level or more, there may be a case where the pressure of the compressor is lowered and the dehumidifying operation is stopped.

    However, in the present invention, since correction is performed a plurality of times, the correction amount in one correction can be suppressed. In other words, since the suppression of the cooling capacity can be minimized, it is possible to surely prevent the dehumidification operation from being forcibly separated due to a rapid pressure drop of the compressor (21).

    According to the third aspect of the invention, since the correction amount is controlled according to the detected temperature difference between the blown air and the intake air before the dehumidifying operation, the temperature controller (36) controls according to the refrigeration load in the refrigerator. It can be performed. Specifically, when the detected temperature difference between the intake air and the blown air before the dehumidifying operation is large, the temperature correction unit (37) can suppress the correction amount and ensure the cooling capacity. On the other hand, when the detected temperature difference between the intake air and the blown air before the dehumidifying operation is small, the temperature correction unit (37) can suppress the cooling capacity by increasing the correction amount. By doing so, when the refrigeration load in the warehouse is large, the detection temperature of the blowout temperature detector (34) can be corrected to be higher to increase the cooling capacity, while when the refrigeration load in the warehouse is small The cooling capacity can be suppressed by correcting the detected temperature of the blowing temperature detector (34) to be lower.

It is the perspective view which looked at the refrigeration equipment for containers concerning an embodiment from the warehouse outside. It is side surface sectional drawing which shows the structure of the container refrigeration apparatus which concerns on embodiment. It is a front view when the casing which concerns on embodiment is seen from the warehouse inner side. It is a piping system diagram showing a refrigerant circuit concerning an embodiment. It is a graph which shows the blowing temperature in the width direction of a store | warehouse | chamber at the time of the cooling operation | movement which concerns on a prior art example, and a dehumidification operation | movement. It is a graph which shows the relationship between the temperature of the suction air and blowing air at the time of the dehumidification operation | movement which concerns on Embodiment 1. FIG. It is a graph which shows the relationship between the temperature of suction air and blowing air at the time of the dehumidification operation | movement which concerns on Embodiment 2. FIG.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

<Embodiment 1>
As shown in FIGS. 1 to 3, the container refrigeration apparatus (10) of the first embodiment performs refrigeration or freezing in a container (C) used for marine transportation and the like. The container refrigeration apparatus (10) is disposed so as to close the open end of a box-shaped container (C) whose one end on its side is open. Further, the container refrigeration apparatus (10) includes a refrigerant circuit (16) as shown in FIG. That is, the container refrigeration apparatus (10) is configured to cool the air in the container (C) using the refrigeration cycle of the refrigerant circuit (16). Although not shown in the figure, a load to be cooled is loaded in the container (C).

-Configuration of container refrigeration system-
As shown in FIGS. 1 and 2, the container refrigeration apparatus (10) has a casing (C) with a peripheral edge attached to the container (C) so as to close the opening end surface of the container (C) formed in a bottomed cylindrical shape. 11).

    As shown in FIG. 2, the casing (11) includes an outer casing (12) located on the outer side and an inner casing (13) located on the inner side. The outer casing (12) and the inner casing (13) are made of a metal aluminum alloy.

    The outside casing (12) is attached to the opening of the container (C) so as to close the opening end surface of the container (C). The outside-compartment casing (12) is formed so that the lower part swells to the inside of the warehouse.

    The internal casing (13) is formed along the external casing (12) and bulges inward of the internal space corresponding to the external casing (12). A heat insulating material (14) is provided in the space between the external casing (12) and the internal casing (13). As shown in FIG. 1, the casing (11) has two opening holes (27) that are open at positions closer to the upper side thereof, arranged side by side in the width direction. An opening / closing door (28) that can be opened and closed at the time of maintenance is attached to the opening hole (27). Further, an electrical component box (29) is disposed in a position adjacent to the external fan (24) in the external storage space (S1) of the casing (11).

    The lower part of the casing (11) is formed so as to bulge out toward the inner side of the container (C), whereby a recess (11a) is formed outside the lower part of the casing (11). The That is, an outside storage space (S1) is formed on the outer side of the lower part of the casing (11), and an inner storage space (S2) is formed on the inner side of the upper part of the casing (11).

    A partition plate (48) is provided inside the casing (11). The partition plate (48) is configured as a substantially rectangular plate member, and is erected in such a posture as to face the casing (11). By this partition plate (48), the interior of the container (C) and the interior storage space (S2) are partitioned. A gap is formed between the upper end of the partition plate (48) and the ceiling surface in the container (C). This gap constitutes a suction port (51) for taking the air inside the container (C) into the storage space (S2). A gap is formed between the lower end of the partition plate (48) and the bottom surface of the container (C). This gap constitutes an air outlet (52) that blows out the air processed by the container refrigeration apparatus (10) (that is, the air that has cooled the internal air) into the internal space.

    In the external storage space (S1), a compressor (21), a condenser (23), an external fan (24), and an external motor (45) are provided. The compressor (21) and the condenser (23) are connected to the refrigerant circuit (16). The outside fan (24) is rotated by the outside motor (45), attracts outside air into the outside storage space (S1), and sends it to the condenser (23). In the condenser (23), heat is exchanged between the outside air and the refrigerant.

    In the internal storage space (S2), a reheater (32), an evaporator (25), a blower unit (30), and a suction temperature sensor (33) are provided in the upper part inside the storage of the casing (11). The blowing temperature sensor (34) is provided in the lower part inside the store | warehouse | chamber (11). Specifically, in the storage space (S2), the suction temperature sensor (33) is disposed at the uppermost position near the suction port (51), and the blower unit (30) is disposed directly below the suction temperature sensor (33). The evaporator (25) is disposed directly below the blower unit (30), the reheater (32) is disposed directly below the evaporator (25), and the blowout temperature sensor is located at the lower part closest to the blowout port (52). (34) is arranged.

    The said ventilation unit (30) sends the air in a store | warehouse | chamber of a container (C) to an evaporator (25). The blower unit (30) is provided in the upper part of the storage space (S2), and two units are arranged side by side in the width direction of the casing (11). Each blower unit (30) includes a fan housing (31), an internal fan (26), and an internal motor (46). The internal fan (26) is rotationally driven by the internal motor (46), and draws the air inside the container (C) from the suction port (51) on the upper side of the partition plate (48) to draw the evaporator (25 ). The inside air that has been heat exchanged with the refrigerant in the evaporator (25) is sent from the lower outlet (52) of the partition plate (48) to the inner side by the inside fan (26). Returned to

    The said suction temperature sensor (33) is a sensor which detects the temperature of the air taken in from the store | warehouse | chamber of a container (C), Comprising: The suction temperature detector which concerns on this invention is comprised. The suction temperature sensor (33) is provided at a height between the two air blowing units (30, 30) and substantially horizontal with the upper portion of the air blowing unit (30). The suction temperature sensor (33) detects the temperature of the air (that is, the air in the container (C)) that is sent from the interior of the container (C) to the interior storage space (S2).

    The evaporator (25) cools the internal air of the container (C) taken into the internal storage space (S2) through heat exchange with the refrigerant. In particular, in the dehumidifying operation, the evaporator (25) is configured to cool the internal air and dehydrate the moisture in the air to perform dehumidification (that is, cooling dehumidification). The evaporator (25) is connected to the refrigerant circuit (16).

    The reheater (32) is for reheating the air that has been cooled and dehumidified in the evaporator (25) to a set temperature in the cabinet, and constitutes a heater according to the present invention. The reheater (32) is configured to heat the air that has flowed out of the evaporator (25) in the dehumidifying operation (that is, air that has been cooled and dehumidified).

    The said blowing temperature sensor (34) is a sensor which detects the temperature of the air which blows off in the store | warehouse | chamber interior of a container (C) from the storage space (S2) in a store | warehouse | chamber, Comprising: The blowing temperature detector which concerns on this invention is comprised. ing. The blowout temperature sensor (34) is located at a substantially central position in the width direction between the bulging portion of the lower casing (13) and the partition plate (48) in the lower storage space (S2). Is provided.

    As shown in FIG. 3, an evaporator holding frame (15) that extends in the width direction of the casing (11) and holds the evaporator (25) is provided at the upper portion inside the casing (11). A central portion in the width direction of the evaporator holding frame (15) is connected to an upper end portion of a frame support member (43) that is fixed to the central portion in the width direction inside the casing (11) and extends in the vertical direction.

    The side stay (40) is erected on both ends in the width direction of the casing (11), and is connected to the lower part of the casing (11) that bulges to the inside of the warehouse. The evaporator holding frame (15) has both ends in the width direction supported by the side stays (40) and the center in the width direction supported by the frame support member (43). The frame support member (43) is a columnar member having a substantially U-shaped cross section, and is provided so as to extend in the vertical direction at the central portion in the width direction inside the warehouse at the bottom of the casing (11).

-Configuration of refrigerant circuit-
As shown in FIG. 4, the refrigerant circuit (16) includes a compressor (21), a condenser (23), a receiver (73), a first subcooling heat exchanger (60), and a second excess refrigerant. A cooling heat exchanger (63), an expansion valve (76), an evaporator (25), and a reheater (32) are connected by a refrigerant pipe (17). The refrigerant circuit (16) is switched between the refrigeration operation, the freezing operation, and the dehumidifying operation by the controller (35).

    The refrigerant circuit (16) is a closed circuit filled with a refrigerant. In the refrigerant circuit (16), the discharge side of the compressor (21) is connected to the inlet side of the condenser (23) via the flow rate control valve (18). In addition, a part of the piping on the suction side of the flow rate control valve (18) branches, and then branches further to the first to third branch pipes (66 to 68) to reheat solenoid valve (70) and heater solenoid respectively. It is connected to the valve (71) and the hot gas solenoid valve (72).

    The condenser (23) condenses the refrigerant by dissipating the heat of the discharged refrigerant flowing into the air outside the warehouse. The condenser (23) is configured by a so-called cross fin type fin-and-tube heat exchanger provided with a heat transfer tube which is a circular tube. In the vicinity of the condenser (23), an outside fan (24) for taking air outside the container (C) into the condenser (23) is provided.

    The receiver (73) is a vertically long and cylindrical sealed container. The receiver (73) is provided on the downstream side of the refrigerant in the condenser (23), and the refrigerant flowing in from the condenser (23) is separated into a saturated liquid and a saturated gas, and the saturated liquid flows out. .

    The first subcooling heat exchanger (60) includes a first high-pressure side channel (61) and a first low-pressure side channel (62). The first subcooling heat exchanger (60) exchanges heat between the refrigerants flowing through the first high pressure side flow path (61) and the first low pressure side flow path (62), so that the first high pressure side flow path (61) The refrigerant flowing through the refrigerant is supercooled.

    A part of the refrigerant flowing out of the first subcooling heat exchanger (60) branches and flows through the fourth branch pipe (69). The fourth branch pipe (69) is provided with a solenoid valve (74) and a capillary tube (75), and the refrigerant flowing through the fourth branch pipe (69) is decompressed by the capillary tube (75). The decompressed refrigerant flows into the second low pressure side flow path (65) of the second subcooling heat exchanger (63).

    The second subcooling heat exchanger (63) includes a second high pressure side flow path (64) and a second low pressure side flow path (65). The second subcooling heat exchanger (63) exchanges heat between the refrigerants flowing through the second high-pressure side flow path (64) and the second low-pressure side flow path (65), so that the second high-pressure side flow path (64) The refrigerant flowing through the refrigerant is supercooled.

    The expansion valve (76) expands and depressurizes the refrigerant flowing through the refrigerant pipe (17), and constitutes an expansion mechanism according to the present invention. The other end of the first to third branch pipes (66 to 68) is connected to the outflow side of the expansion valve (76).

    The first branch pipe (66) has one end connected to the discharge side of the compressor (21) and the other end connected to the outflow side of the expansion valve (76). A drain pan heater (77) is provided in the middle of the first branch pipe (66). The drain pan heater (77) heats the drain pan in which water condensed in the evaporator (25) is stored, and melts water frozen in the drain pan. The drain pan heater (77) is configured such that the refrigerant discharged from the compressor (21) (that is, hot gas) flows into the drain pan heater (77). In addition, the refrigerant | coolant flow volume which flows through a 1st branch pipe (66) is controlled by the opening degree of a heater solenoid valve (71).

    The second branch pipe (67) has one end connected to the discharge side of the compressor (21) and the other end connected to the outflow side of the expansion valve (76). The flow rate of the refrigerant flowing through the second branch pipe (67) is controlled by the opening degree of the hot gas solenoid valve (72).

    The third branch pipe (68) has one end connected to the discharge side of the compressor (21) and the other end connected to the outflow side of the expansion valve (76). A reheater (32) is provided in the middle of the third branch pipe (68). In addition, the refrigerant | coolant flow volume which flows through a 3rd branch pipe (68) is adjusted with the opening degree of the reheat solenoid valve (70).

    In the dehumidifying operation, the reheater (32) heats the air by exchanging heat between the discharged refrigerant that has flowed in and the air that has been cooled and dehumidified by the evaporator (25). The reheater (32) is configured by a so-called cross fin type fin-and-tube heat exchanger having a heat transfer tube which is a circular tube. The heat transfer tube of the reheater (32) extends along the width direction in the container (C). The refrigerant flowing out of the reheater (32) is decompressed by the capillary tube (75) and then flows into the outflow side of the expansion valve (76).

    The evaporator (25) dissipates heat from the air taken from the inside of the container (C) to the refrigerant flowing out of the expansion valve (76) to evaporate the refrigerant, and cools the taken-in air. is there. The evaporator (25) is constituted by a so-called cross fin type fin-and-tube heat exchanger provided with a heat transfer tube which is a circular tube. The heat transfer tube of the evaporator (25) extends along the width direction in the container (C). In the vicinity of the evaporator (25), an internal fan (26) is provided for taking air in the container (C) into the evaporator (25). The refrigerant circuit (16) cools the air taken from the container (C), cools the air taken from the container (C), and condenses moisture in the air. The dehumidifying operation for dehumidifying (ie, cooling dehumidification) is performed.

    The controller (35) controls the operation of the refrigerant circuit (16). The controller (35) includes a temperature control unit (36) and a temperature correction unit (37).

    The temperature control unit (36) controls the refrigerant circuit (16) based on the detected temperature detected by the outlet temperature sensor (34) so as to bring the detected temperature closer to the set temperature in the cabinet. The temperature control part which concerns on invention is comprised.

    The temperature correction unit (37) corrects the value of the detected temperature (Ts) of the blowing temperature sensor (34) during the dehumidifying operation, and constitutes a temperature corrector according to the present invention. Specifically, the temperature correction unit (37) generates a blowout when the detected temperature (Tr) of the suction temperature sensor (33) is lower than the detected temperature (Ts) of the blowout temperature sensor (34) during the dehumidifying operation. The detected temperature (Ts) value of the temperature sensor (34) is corrected to be lower than the detected temperature (Tr) of the suction temperature sensor (33). And a temperature control part (36) controls a refrigerant circuit (16) based on this correct | amended value.

    In addition, the temperature correction unit (37) is configured to detect a difference (detected temperature difference (ΔT)) between the detected temperature (Ts) of the blowing temperature sensor (34) and the detected temperature (Tr) of the suction temperature sensor (33) before dehumidifying operation As the value increases, the correction amount of the value of the detected temperature (Ts) of the blowing temperature sensor (34) is reduced.

    Specifically, in the first embodiment, the temperature correction unit (37) detects the preset reference value 0.5 based on the detection temperature (Tr) of the suction temperature sensor (33) and the detection of the discharge temperature sensor (34). The value divided by the difference (ΔT) from the temperature (Ts) is used as the correction amount. That is, the correction amount is represented by 0.5 / ΔT.

    That is, if the detected temperature difference (ΔT) between the blown air and the intake air is large, it is presumed that the refrigeration load of the internal air is high, so it is necessary to ensure the internal cooling capacity. For this reason, the temperature correction unit (37) suppresses the correction amount in order to ensure the cooling capacity. When the temperature correction unit (37) suppresses the correction amount, the detected temperature (Ts) of the blowing temperature sensor (34) is corrected to be higher (however, it is not more than Tr). And since a temperature control part (36) controls a refrigerant circuit (16) so that the value of the detected temperature corrected highly may approach the preset temperature in a store | warehouse | chamber, cooling capacity becomes large. For this reason, in the state where the freezing load in a warehouse is large, cooling capacity does not run short.

    On the other hand, the temperature correction unit (37) detects the difference between the detected temperature (Ts) of the blowing temperature sensor (34) and the detected temperature (Tr) of the suction temperature sensor (33) (detected temperature difference (ΔT)) before the dehumidifying operation When becomes smaller, the correction amount of the detected temperature (Ts) value of the blowing temperature sensor (34) is increased. That is, when the detected temperature difference (ΔT) between the blown air and the intake air is small, it is estimated that the refrigeration load of the internal air is small, so the cooling capacity in the internal space is suppressed. For this reason, in the temperature correction unit (37), the correction amount is increased in order to suppress the cooling capacity.

    When the temperature correction unit (37) increases the correction amount, the detected temperature (Ts) of the blowout temperature sensor (34) is corrected to be lower (but not more than Tr). And since a temperature control part (36) controls a refrigerant circuit (16) so that the value of the detected temperature corrected low may be brought close to the preset temperature in a store | warehouse | chamber, cooling capacity is suppressed. For this reason, in the state where the refrigeration load in the warehouse is small (for example, refrigeration operation, etc.), even if the temperature unevenness of the blown air occurs in the width direction of the warehouse, the blowing temperature rises as a whole. Thereby, the low-temperature failure to the cargo in a warehouse can be prevented reliably.

-Driving action-
The operation of the container refrigeration apparatus (10) will be described with reference to FIG. In FIG. 4, the flow of the refrigerant during the operation is indicated by solid arrows.

-Cooling operation-
The container refrigeration apparatus (10) starts the cooling operation by starting the compressor (21), the external fan (24), and the internal fan (26). At this time, the reheat solenoid valve (70), the heater solenoid valve (71), and the hot gas solenoid valve (72) are all closed. The cooling operation includes a freezing operation and a refrigeration operation.

    In the refrigerant circuit (16) of the container refrigeration apparatus (10), the refrigerant discharged from the compressor (21) is sent to the condenser (23) via the flow rate control valve (18). In the condenser (23), the refrigerant circulating inside exchanges heat with outside air sent by the outside fan (24). As a result, the refrigerant dissipates heat to the outside air and condenses.

    The refrigerant condensed in the condenser (23) is separated into a saturated liquid and a saturated gas in the receiver (73), and the saturated liquid is sent to the first subcooling heat exchanger (60). In the first subcooling heat exchanger (60), the refrigerants flowing through the first high-pressure side flow path (61) and the first low-pressure side flow path (62) exchange heat, and the first high-pressure side flow path (61) The refrigerant flowing through is supercooled.

    A part of the refrigerant subcooled in the first subcooling heat exchanger (60) is sent to the second subcooling heat exchanger (63) via the solenoid valve (74), while the remaining is the fourth branch. It flows through the pipe (69) and is sent to the second subcooling heat exchanger (63). The refrigerant flowing through the fourth branch pipe (69) is reduced in pressure in the capillary tube (75) after passing through the electromagnetic valve (74). In the second subcooling heat exchanger (63), the refrigerants flowing through the second high-pressure side flow path (64) and the second low-pressure side flow path (65) exchange heat, and the second high-pressure side flow path (64). The refrigerant flowing through is supercooled.

    The refrigerant supercooled by the second supercooling heat exchanger (63) is depressurized by the expansion valve (76) and then sent to the evaporator (25). In the evaporator (25), the refrigerant circulating in the interior exchanges heat with the internal air sent by the internal fan (26). As a result, the refrigerant absorbs heat from the internal air and evaporates, and the internal air is cooled. As shown in FIG. 2, the internal air flows into the internal storage space (S2) from the suction port (51) and passes through the evaporator (25). And after cooling with an evaporator (25), it passes through the reheater (32) in a stop, and is blown out from a blower outlet (52), and returns to the inside of a warehouse. The refrigerant evaporated in the evaporator (25) is sucked into the compressor (21) and compressed again.

−Dehumidifying operation−
Operation of the container refrigeration apparatus (10) is started by starting the compressor (21), the external fan (24), and the internal fan (26). At this time, the reheat solenoid valve (70) is opened.

    In the evaporator (25) during the dehumidifying operation, the refrigerant circulating inside exchanges heat with the internal air sent by the internal fan (26). As a result, the refrigerant absorbs heat from the internal air and evaporates, the internal air is cooled, and moisture in the air is condensed. For this reason, the inside air is dehumidified.

    In the refrigerant circuit (16) of the container refrigeration apparatus (10), the refrigerant discharged from the compressor (21) is sent to the condenser (23) via the flow rate control valve (18). At this time, part of the refrigerant discharged from the compressor (21) flows through the third branch pipe (68) via the reheat solenoid valve (70) and flows into the reheater (32). In the reheater (32), the refrigerant circulating inside exchanges heat with the air cooled and dehumidified by the evaporator (25). As a result, the refrigerant dissipates heat to the internal air and condenses, and the internal air is heated.

    Here, since the reheater (32) has a small number of heat transfer tubes and the refrigerant temperature difference between the inlet side and the outlet side is large, the air flowing out of the reheater (32) is as shown in FIG. Further, temperature unevenness is likely to occur in the width direction in the cabinet. And since the blowing temperature sensor (34) is provided in the approximate center of the width direction in a store | warehouse | chamber, compared with the center of the width direction in the position away from the blowing temperature sensor (34) (right side in FIG. 3). Becomes lower. The temperature control unit (36) controls the refrigerant circuit (16) so that the detected temperature (Ts) of the blowing temperature sensor (34) (that is, the blowing temperature at the center in the width direction) approaches the set value of the internal temperature. doing.

    Conventionally, since the internal temperature is controlled based on the temperature in the center in the internal width direction where the temperature becomes high, the load becomes overcooled near the end in the internal width direction, causing a low temperature failure. was there.

    As shown in FIG. 2, the internal air flows into the internal storage space (S2) from the suction port (51) and passes through the evaporator (25). And after cooling with an evaporator (25), it passes a reheater (32). After being heated by the reheater (32), it is blown out from the outlet (52) and returned to the interior.

    Next, the relationship between the temperature of the intake air and the blown air during the dehumidifying operation after the refrigeration operation will be described with reference to FIG. First, in the refrigeration operation before the dehumidifying operation, the suction temperature is detected as 4.5 ° C. by the suction temperature sensor (33), and the blowing temperature is detected as 4 ° C. by the blowing temperature sensor (34). Therefore, the temperature difference (ΔT) between the suction temperature and the discharge temperature is 0.5 ° C. Therefore, the temperature correction unit (37) sets the correction amount to 1 ° C. from 0.5 / ΔT. In the first embodiment, the correction amount is limited to 2 ° C. or less.

    Next, after the dehumidifying operation is started, when the reheat solenoid valve (70) is opened and the refrigerant discharged from the compressor (21) flows to the reheater (32), temperature unevenness of the blown air occurs. That is, the blowing temperature at the center in the width direction increases. And a temperature control part (36) controls the cooling capacity of a refrigerant circuit (16) so that the value of the detection temperature (Ts) of a blowing temperature sensor (34) may be kept at 4 degreeC. On the right side in FIG. 3, the blown air decreases. For this reason, as indicated by a broken line in FIG. 6, the detected temperature (Ts) of the blowing temperature sensor (34) is maintained at 4 ° C., while the average value of the blowing temperature gradually decreases. For this reason, the temperature of the internal air also decreases, and the temperature of the intake air gradually decreases.

    In the conventional container refrigeration apparatus, as shown in FIG. 6, when the refrigerant circuit is controlled so as to keep the detected temperature (Ts) of the blowing temperature sensor at 4 ° C., the average value of the blown air and the temperature of the intake air are Both will decline. And in order to maintain the value of the detection temperature (Ts) of the blowing temperature sensor at 4 ° C., to control the fan outside the refrigerator or increase the capacity of the compressor to further increase the cooling capacity, the average value of the blowing air and The temperature of the intake air further decreases.

    However, in the first embodiment, when the temperature of the blown air and the temperature of the suction air are reversed and the temperature of the blown air becomes higher (that is, the detected temperature (Tr) of the suction air becomes 4 ° C. or less), the temperature The correction unit (37) detects the temperature detected by the outlet temperature sensor (34) so that the detected temperature (Ts) of the outlet temperature sensor (34) is smaller than the detected temperature (Tr) of the suction temperature sensor (33). The value of Ts) is corrected to 3 ° C. (that is, the correction amount is 1 ° C.). In this way, the temperature control unit (36) controls the cooling capacity of the refrigerant circuit (16) so as to keep the detected temperature (Ts) value of the blowing temperature sensor (34) at 4 ° C. Control the refrigerant circuit (16). For this reason, the detection temperature (Tr) of the blowing temperature sensor (34) and the suction temperature sensor (33) gradually increases. By carrying out like this, since the temperature of blowing air becomes high as a whole, the low temperature disorder | damage | failure of the load in the warehouse of a container (C) can be prevented.

    After that, for example, after 30 minutes, if the detected temperature (Ts) of the blowing temperature sensor (34) is equal to or higher than the detected temperature (Tr) of the suction temperature sensor (33), the temperature correction unit (37) The correction amount is obtained by subtracting 0.5 from the correction amount. The temperature controller (36) controls the internal temperature based on the new correction amount.

    Finally, when the detected temperature (Tr) of the suction temperature sensor (33) satisfies a predetermined condition (Tr ≧ Ts + 1.5 ° C.), the reheater (32) is turned off. In addition, this 1.5 degreeC is a mere illustration, and is not restricted to this.

-Effect of Embodiment 1-
According to the first embodiment, when the detected temperature (Ts) of the blown air and the detected temperature (Tr) of the intake air are reversed, the value of the detected temperature (Ts) of the blown air is corrected so as to be reduced. Cooling capacity during operation can be suppressed. For this reason, the temperature of the air blown out into the warehouse can be raised as a whole. Thereby, even if the temperature nonuniformity of the blowing air has arisen in the width direction of a store | warehouse | chamber, the low temperature disorder | damage | failure to the load in a store | warehouse | chamber can be prevented reliably.

    Further, according to the first embodiment, since the correction amount is controlled according to the temperature difference (ΔT) between the blown air and the intake air before the dehumidifying operation, the temperature control unit (36 ) Can be controlled. Specifically, when the temperature difference (ΔT) between the intake air and the blown air before the dehumidifying operation is large, the temperature correction unit (37) can secure the cooling capacity by suppressing the correction amount. On the other hand, when ΔT of the intake air and the blown air before the dehumidifying operation is small, the temperature correction unit (37) can increase the correction amount to suppress the cooling capacity. In this way, when the refrigeration load in the warehouse is large, the detection temperature (Ts) of the blowout temperature sensor (34) can be corrected to be higher to increase the cooling capacity, while the refrigeration load in the warehouse is small. In this case, the cooling temperature can be suppressed by correcting the detected temperature (Ts) of the blowing temperature sensor (34) to be low.

<Embodiment 2 of the invention>
Next, Embodiment 2 of the present invention will be described with reference to FIG. The container refrigeration apparatus (10) according to the second embodiment is different from the first embodiment in the content of control during the dehumidifying operation. In the second embodiment, only parts different from the first embodiment will be described.

    Specifically, in the dehumidifying operation, the temperature correction unit (37) according to the second embodiment is configured such that the detected temperature (Tr) of the suction temperature sensor (33) is higher than the detected temperature (Ts) of the outlet temperature sensor (34). When it becomes low, the value of the detected temperature (Ts) of the blowing temperature sensor (34) is corrected to be 0.2 ° C. lower. At this time, the temperature correction unit (37) sets the correction amount under a predetermined condition (Ts−ΔTx). In the second embodiment, ΔTx is a variable number, and is set to 0.2 as an example.

    After that, when the detected temperature (Ts) of the blowout temperature sensor (34) becomes higher than the detected temperature (Tr) of the suction temperature sensor (33), the detected temperature (Ts) of the blowout temperature sensor (34) again. Correct the value 0.2 ° C lower. At this time, the temperature correction unit (37) obtains the correction amount under a predetermined condition (Ts−N × ΔTx). In the second embodiment, N is set to 2 as an example. N × ΔTx is set to 2 ° C. or less. In this way, it is possible to reliably prevent a low-temperature failure by repeatedly correcting the value of the detected temperature (Ts) of the blown air. The number of repetitions of this operation is limited to 10 times.

    Specifically, when the temperature of the blown air and the temperature of the suctioned air are reversed and the temperature of the blown air becomes higher (that is, the detected temperature (Tr) of the sucked air becomes 4 ° C. or less), the temperature correction unit ( 37) corrects the value of the detected temperature (Ts) of the blowing temperature sensor (34) to 3.8 ° C. In this way, the temperature control section (36) controls the cooling capacity of the refrigerant circuit (16) so as to keep the value of the detected temperature (Ts) of the blowing temperature sensor (34) at 3.8 ° C. The refrigerant circuit (16) is controlled by suppressing the capacity. For this reason, the detection temperature (Ts) of the blowing temperature sensor (34) gradually increases. For example, 10 minutes after that, when the detected temperature (Ts) of the blown air and the detected temperature (Tr) of the intake air are reversed to increase the detected temperature (Ts) of the blown air, the temperature correction unit (37) The detected temperature (Ts) value of the temperature sensor (34) is further lowered by 0.2 ° C. and corrected to 3.6 ° C. In this way, the temperature control unit (36) controls the cooling capacity of the refrigerant circuit (16) so as to keep the value of the detected temperature (Ts) of the blowing temperature sensor (34) at 3.6 ° C. The refrigerant circuit (16) is controlled by suppressing the capacity. For this reason, the detection temperature (Tr) of the blowing temperature sensor (34) and the suction temperature sensor (33) gradually increases. By carrying out like this, since the temperature of blowing air becomes high as a whole, the low temperature disorder | damage | failure of the load in the warehouse of a container (C) can be prevented.

    Finally, when the detected temperature (Tr) of the suction temperature sensor (33) satisfies a predetermined condition (Tr ≧ Ts + 1.5 ° C.), the reheater (32) is turned off. In addition, this 1.5 degreeC is a mere illustration, and is not restricted to this.

-Effect of Embodiment 2-
According to the second embodiment, when the detected temperature of the blown air and the sucked air is reversed again after being corrected once, the value of the detected temperature of the blown air is corrected again to be lower, so that the cargo in the warehouse can be more reliably transferred. Can prevent the low temperature failure. Here, if the cooling capacity is suppressed to a predetermined level or more, the pressure of the compressor decreases, and the dehumidifying operation may be forcibly separated. However, in the second embodiment, correction is performed a plurality of times, so that the correction amount in one correction can be suppressed. That is, since the suppression of the cooling capacity can be minimized, it is possible to surely prevent the dehumidification operation from being forcibly separated due to a rapid pressure drop of the compressor (21). Other configurations, operations and effects are the same as those of the first embodiment.

<Other embodiments>
The present invention may be configured as follows for the first or second embodiment.

    In the first or second embodiment, a limit may be provided for the correction amount of the temperature correction unit (37). For example, the correction limit may be set so that the correction amount is limited to 2 ° C. or less.

    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 a container refrigeration apparatus.

16 Refrigerant circuit 21 Compressor 23 Expansion valve 25 Evaporator 32 Reheater 33 Suction temperature sensor 34 Blowout temperature sensor 36 Temperature control unit 37 Temperature correction unit 76 Expansion valve

Claims (3)

A refrigerant circuit (16) in which a compressor (21), a condenser (23), an expansion mechanism (76), and an evaporator (25) are connected in order, and air that has flowed out of the evaporator (25) A container refrigeration apparatus comprising a heater (32) for heating, and performing a dehumidifying operation for heating in the heater (32) air that has been sucked from inside the container cabinet and cooled and dehumidified in the evaporator (25) There,
A suction temperature detector (33) for detecting the temperature of air sucked into the evaporator (25);
A blowing temperature detector (34) for detecting the temperature of the air heated by the heater (32);
A temperature control unit (36) for controlling the dehumidifying operation based on the value of the detected temperature of the blow-out temperature detector (34);
In the dehumidifying operation, when the detected temperature of the suction temperature detector (33) becomes lower than the detected temperature of the outlet temperature detector (34), the detected temperature value of the outlet temperature detector (34) is A container refrigeration apparatus comprising a temperature correction unit (37) that corrects a temperature lower than a detection temperature of a temperature detector (33). In claim 1,
In the dehumidifying operation after correcting the temperature detected by the blowout temperature detector (34), the temperature correction unit (37) again detects the detected temperature of the suction temperature detector (33) as the blowout temperature detector (34). When the temperature is lower than the detected temperature, the temperature detected by the outlet temperature detector (34) is corrected to be lower than the temperature detected by the suction temperature detector (33). Container refrigeration equipment. In claim 1 or 2,
The temperature correction unit (37) is configured to increase the temperature difference between the blowing temperature detector (34) and the suction temperature detector (33) before the dehumidifying operation. The container refrigeration apparatus is configured to reduce the correction amount of the detected temperature value while increasing the correction amount as the detected temperature difference decreases.

Images