JP2011158144A - Refrigeration device - Google Patents

Abstract

[PROBLEMS] To prevent residual frost in a drain pan during a defrosting operation, and to prevent poor cooling of an evaporator during a cooling operation.
A refrigeration apparatus (10) includes a forward cycle cooling operation in which a refrigerant is evaporated by an evaporator (50) and a reverse cycle defrosting operation in which refrigerant discharged from a compressor (30) is supplied to the evaporator (50). A refrigerant circuit (20) for switching between, a supercooling heat exchanger (40) for supercooling the liquid refrigerant, and a drain pan coil (52) for heating the drain pan of the evaporator (50) by the liquid refrigerant during the cooling operation ing. Further, the refrigeration apparatus (10) detects the temperature of the first temperature sensor (64) that detects the refrigerant temperature at the outlet of the drain pan coil (52) during the defrosting operation and the temperature of the evaporator (50) during the defrosting operation. The detected temperature of the second temperature sensor (65) and the first temperature sensor (64) rises to a predetermined first temperature or higher, and the detected temperature of the second temperature sensor (65) rises to a predetermined second temperature or higher. Then, the defrost control part (71) which complete | finishes a defrost operation is provided.
[Selection] Figure 1

Description

    The present invention relates to a refrigeration apparatus, and particularly relates to measures against defrost.

    Conventionally, as shown in Patent Document 1, a refrigerating apparatus is connected to a compression mechanism, a four-way switching valve, a condenser, a supercooling heat exchanger, a drain pan coil, an expansion valve, and an evaporator in order, so that refrigerant circulation is reversible. Some have a refrigerant circuit. The cooling operation of the refrigeration apparatus is performed with the refrigerant circuit as a positive cycle. That is, the refrigerant discharged from the compression mechanism is condensed by the condenser to become a liquid refrigerant, and this liquid refrigerant is cooled by the supercooling heat exchanger. The cooled supercooled liquid refrigerant heats the drain pan with the drain pan coil, then depressurizes with the expansion valve, evaporates with the evaporator, and returns to the compressor. This refrigerant circulation is repeated, and the internal air is cooled by the evaporator.

    The defrosting operation of the refrigeration apparatus is performed by switching the refrigerant circuit to the reverse cycle. That is, the refrigerant discharged from the compression mechanism flows into the evaporator, and the frosting of the evaporator is released by the high-temperature refrigerant (hot gas), and then flows into the drain pan coil to heat the drain pan. Thereafter, the refrigerant returns to the compression mechanism through the condenser. This circulation is repeated to remove the frost on the evaporator.

JP 2009-287800 A

    However, in the conventional refrigeration apparatus, the defrosting operation is terminated when the temperature sensor provided in the evaporator rises to a predetermined temperature, and thus there is a problem that the drain pan may remain frosted.

    That is, in the refrigeration apparatus that does not include the supercooling heat exchanger, the liquid refrigerant condensed in the condenser is not cooled. Therefore, the temperature of the liquid refrigerant during the cooling operation is normally 30 ° C to 40 ° C, and at least 0 ° C or higher. Therefore, since the drain pan is heated during the normal cooling operation, even if residual frost is generated in the drain pan at the end of the defrosting operation, the residual frost can be released during the cooling operation.

    However, the above-described conventional refrigeration apparatus is provided with a supercooling heat exchanger to enhance the refrigeration effect (enthalpy difference at the inlet / outlet of the evaporator) and improve the refrigeration capacity (refrigerant circulation amount × refrigeration effect). When the liquid refrigerant is cooled by this supercooling heat exchanger, the degree of supercooling can be set to 20 ° C., so that the temperature of the liquid refrigerant becomes 0 ° C. or lower when the outside air temperature is low. As a result, the drain pan cannot be defrosted during normal cooling operation. In particular, in the freezing region, the internal temperature is as low as −20 ° C., so that the drain pan frost cannot be thawed.

    Therefore, when the defrosting operation is terminated only with the temperature of the evaporator detected by the temperature sensor and the residual frost in the drain pan is generated, the drain pan frost grows without melting during the cooling operation. And there was a problem that a part of the evaporator was blocked by the frost of the drain pan, resulting in poor cooling of the evaporator.

    This invention is made | formed in view of such a point, and it aims at preventing the residual frost of the drain pan at the time of a defrost operation, and preventing the cooling failure of the evaporator at the time of cooling operation beforehand.

    In the first refrigeration apparatus, a compressor (30), a condenser (32), an expansion mechanism (51), and an evaporator (50) are connected in order, and the evaporator (50) evaporates the refrigerant in the positive cycle. A reversible refrigerant circuit (20) in which refrigerant circulation is performed by switching between a cooling operation and a reverse cycle defrosting operation for supplying refrigerant discharged from the compressor (30) to the evaporator (50); Provided between the supercooler (40) for supercooling the liquid refrigerant condensed in the condenser (32), the condenser (32) and the expansion mechanism (51) of the refrigerant circuit (20), and the cooling operation And a heating section (52) for heating the drain pan of the evaporator (50) with liquid refrigerant. Furthermore, the 1st freezing apparatus detected the 1st temperature detection part (64) which detects the refrigerant | coolant temperature of the exit of the heating part (52) at the time of the said defrost operation, and this 1st temperature detection part (64) A defrosting control unit (71) for ending the defrosting operation based on the refrigerant temperature.

    In the first refrigeration apparatus, a reverse cycle defrosting operation is performed. During the defrosting operation, the first temperature detection unit (64) detects the refrigerant temperature at the outlet of the heating unit (52). And a defrost control part (71) complete | finishes a defrost operation based on the refrigerant | coolant temperature which the said 1st temperature detection part (64) detected.

    In the first refrigeration apparatus, the second refrigeration apparatus includes a second temperature detection unit (65) that detects the temperature of the evaporator (50) during the defrosting operation. And the defrost control part (71) of a 2nd freezing apparatus raises the refrigerant | coolant temperature which the 1st temperature detection part (64) detected to more than predetermined 1st temperature, and a 2nd temperature detection part (65) When the detected evaporator temperature rises to a predetermined second temperature or higher, the defrosting operation is terminated.

    In the second refrigeration apparatus, the second temperature detector (65) detects the temperature of the evaporator (50) during the defrosting operation. Then, the refrigerant temperature detected by the first temperature detector (64) and the evaporator temperature detected by the second temperature detector (65) both rise, and the refrigerant temperature detected by the first temperature detector (64) When the evaporator temperature detected by the second temperature detector (65) rises above the predetermined second temperature when the temperature rises above the predetermined first temperature, the defrost controller (71) ends the defrosting operation.

    The third refrigeration apparatus is the second refrigeration apparatus, wherein the evaporator (50) includes a plurality of refrigerant paths, and the second temperature detection unit (65) includes one refrigerant path of the evaporator (50). It is provided and configured.

    In the third refrigeration apparatus, the second temperature detector (65) detects the temperature of one refrigerant path of the evaporator (50).

    The fourth refrigeration apparatus is the first refrigeration apparatus, wherein the expansion mechanism (51) is composed of an electronic expansion valve (51) whose opening degree can be adjusted, while the evaporator (50 ), A third temperature detector (66) for detecting the refrigerant evaporation temperature, a fourth temperature detector (67) for detecting the refrigerant temperature at the outlet of the evaporator (50) during the cooling operation, and the third The opening degree of the expansion valve (51) is controlled so that the degree of refrigerant superheating based on the evaporation temperature detected by the temperature detector (66) and the refrigerant temperature detected by the fourth temperature detector (67) becomes a predetermined value. And a valve control unit (72). Further, the defrost control unit (71) of the fourth refrigeration apparatus has the refrigerant temperature detected by the first temperature detection unit (64) rising to a predetermined first temperature or more and the third temperature detection unit (66). When the detected temperature detected during the defrosting operation rises to a predetermined third temperature or higher, the defrosting operation is terminated.

    In the fourth refrigeration apparatus, the valve control unit (72) controls the opening degree of the expansion valve (51) based on the degree of refrigerant superheat. And a defrost control part (71) is for the refrigerant | coolant temperature which the 1st temperature detection part (64) detected rises more than predetermined 1st temperature, and controls the degree of refrigerant superheat of the said expansion valve (51) When the detected temperature detected by the third temperature detection unit (66) during the defrosting operation rises above a predetermined third temperature, the defrosting operation is terminated.

    According to a fifth refrigeration apparatus, in the fourth refrigeration apparatus, the evaporator (50) includes a plurality of refrigerant paths, and the third temperature detection unit (66) includes one refrigerant path of the evaporator (50). It is provided and configured.

    In the fifth refrigeration apparatus, the third temperature detector (66) detects the temperature of one refrigerant path of the evaporator (50).

    The sixth refrigeration apparatus includes an electric heater (80) for heating the drain pan (56) and a refrigerant at an inlet of the heating unit (52) during the cooling operation in any of the first to fifth refrigeration apparatuses. When the temperature is lowered to a predetermined low temperature, a heating control unit (73) that operates the electric heater (80) is provided.

    In the sixth refrigeration apparatus, when the refrigerant temperature at the inlet of the heating section (52) during the cooling operation is lowered to a predetermined low temperature, the drain pan (56) is heated by the electric heater (80).

    The seventh refrigeration apparatus is the sixth refrigeration apparatus, wherein the electric heater (80) heats the periphery of the drain port (58) of the drain pan (56) and the drain pipe (57). It is set as the structure which is.

    In the seventh refrigeration apparatus, the drain pipe heater (81) heats the periphery of the drain port (58) of the drain pan (56) and the drain pipe (57).

    According to this refrigeration apparatus, since the defrosting operation is terminated based on the refrigerant temperature at the outlet of the heating unit (52) during the defrosting operation, the residual frost in the drain pan during the defrosting operation is reliably prevented. be able to. As a result, the drain pan frost can be prevented from growing during the cooling operation, so that the drain pan frost can be prevented from partially blocking the evaporator (50). Cooling failure can be reliably prevented.

    That is, since the liquid refrigerant is cooled by the supercooler (40) during the cooling operation, for example, the refrigerant supercooling degree can be set to 20 ° C. However, when the outside air temperature is low, the temperature of the liquid refrigerant becomes 0 ° C. or lower, so that the drain pan cannot be defrosted during the cooling operation. Therefore, since the defrosting operation is terminated based on the refrigerant temperature at the outlet of the heating unit (52) during the defrosting operation, the defrosting operation can reliably defrost the drain pan. As a result, the drain pan frost is prevented from growing during the cooling operation, and the evaporator (50) is not partially blocked by the drain pan frost.

    Further, according to the second refrigeration apparatus, when both the refrigerant temperature at the outlet of the heating unit (52) during the defrosting operation and the evaporator temperature during the defrosting operation reach a predetermined temperature, the defrosting operation is performed. Since it was made to complete | finish, the residual frost of both the evaporator (50) at the time of a defrost operation and a drain pan can be prevented reliably.

    In particular, according to the third refrigeration apparatus, when the second temperature detection unit (65) is provided in one refrigerant path of the evaporator (50), the second temperature detection unit (65 ) Can be provided. As a result, the defrosting of the evaporator (50) can be reliably performed.

    Moreover, according to the said 4th freezing apparatus, a defrost control part (71) makes completion | finish of a defrost operation using the detection temperature of the 3rd temperature detection part (66) for controlling an expansion valve (51). Therefore, the third temperature detector (66) can be used for the opening control of the expansion valve (51) and the end control of the defrosting operation, and the remaining temperature of the evaporator (50) can be increased without increasing the number of parts. The presence or absence of frost can be accurately determined.

    Further, when both the refrigerant temperature at the outlet of the heating unit (52) during the defrosting operation and the refrigerant temperature (evaporator temperature) of the evaporator (50) during the defrosting operation reach a predetermined temperature, the defrosting operation is performed. Since it was made to complete | finish, the residual frost of both the evaporator (50) at the time of a defrost operation and a drain pan can be prevented reliably.

    Further, according to the sixth refrigeration apparatus, since the electric heater (80) is provided, the drain pan (56) can be heated during the cooling operation, and the residual frost of the drain pan (56) can be reliably prevented. Can do.

    Further, according to the seventh refrigeration apparatus, since the drain pan (56) can be heated using the drain pipe heater (81), the drain pipe heater for heating only the drain pipe (57) is omitted. And the number of parts can be reduced.

FIG. 1 is a refrigerant circuit diagram illustrating the refrigeration apparatus according to the first embodiment. FIG. 2 is a refrigerant circuit diagram illustrating the refrigerant flow during the defrosting operation of the first embodiment. FIG. 3 is a refrigerant circuit diagram illustrating the internal unit of the second embodiment. FIG. 4 is a schematic front view illustrating the evaporator according to the second embodiment. FIG. 5 is a schematic front view illustrating the drain pan according to the third embodiment. FIG. 6 is a schematic plan view showing a drain pan according to the fourth embodiment. FIG. 7 is a schematic front view illustrating a drain pan according to the fourth embodiment.

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

<Embodiment 1>
As shown in FIG. 1, the refrigeration apparatus (10), for example, cools the inside of the refrigerator to the freezing region, and includes an outside unit (11) and an inside unit (12), and the outside unit ( 11) and the internal unit (12) are connected by a communication pipe (13, 14).

    The refrigeration apparatus (10) includes a reversible refrigerant circuit (20) with refrigerant circulation. The refrigerant circuit (20) is configured to switch between a forward cycle cooling operation and a reverse cycle defrosting operation. The refrigerant circuit (20) is filled with, for example, R410A as a refrigerant.

    The outside unit (11) includes a condensing unit including a compressor (30), a four-way switching valve (31), a condenser (32), a receiver (33), and a supercooling heat exchanger (40). It is composed. The compressor (30), the four-way selector valve (31), the condenser (32), the receiver (33), and the supercooling heat exchanger (40) are sequentially connected by the refrigerant pipe (21). .

    The discharge side of the compressor (30) is connected to a four-way switching valve (31) via an oil separator (34) and a check valve (2a), and the suction side of the compressor (30) Connected to the path switching valve (31). The oil separator (34) is connected to a refrigerant pipe (21) on the suction side of the compressor (30) via an oil return passage (22).

    The first port of the four-way selector valve (31) is connected to the discharge side of the compressor (30), the second port is connected to the suction side of the compressor (30), and the third port is a condenser. (32) is connected to one end of the gas side, and the fourth port is connected to the gas side communication pipe (14). The four-way switching valve (31) switches to the solid line in FIG. 1 when the refrigerant circuit (20) performs the cooling operation, and switches to the broken line in FIG. 1 when the refrigerant circuit (20) performs the defrosting operation. It is configured as follows.

    The condenser (32) is constituted by, for example, a cross fin type fin-and-tube heat exchanger, and is provided with a condenser fan (32F). One end of the condenser (32) on the gas side is connected to the third port of the four-way selector valve (31) via the gas-side refrigerant pipe (21), and the other end on the liquid side is the liquid-side refrigerant. The pipe (21) is connected to the receiver (33) via the check valve (2b).

    The supercooling heat exchanger (40) constitutes a supercooler that supercools the liquid refrigerant condensed in the condenser (32), and includes a primary side passage (41) and a secondary side passage (42). For example, it is comprised with the plate-type heat exchanger. The inflow end of the primary passage (41) is connected to the receiver (33) through the liquid side refrigerant pipe (21), and the outflow end is connected to the liquid side via the liquid side refrigerant pipe (21). Connected to the connecting pipe (13). The inflow end of the secondary side passage (42) is connected to the liquid side refrigerant pipe (21) between the primary side passage (41) and the liquid side communication pipe (13) via the branch pipe (43). The outlet end is connected to the refrigerant pipe (21) on the suction side of the compressor (30) via the injection pipe (44). The branch pipe (43) is provided with a supercooling expansion valve (4a) whose opening degree can be adjusted.

    The supercooling heat exchanger (40) branches a part of the liquid refrigerant from the condenser (32) into the secondary passage (42), and the refrigerant flowing through the secondary passage (42) and the primary side Heat is exchanged with the refrigerant flowing through the passage (41) to cool the liquid refrigerant flowing through the primary side passage (41).

    A bypass passage (23) is provided between the condenser (32) and the communication pipe (13) on the liquid side. The bypass passage (23) is a passage through which the refrigerant flows during the defrosting operation, and one end is between the outlet end of the primary passage (41) of the supercooling heat exchanger (40) and the branch pipe (43). The other end of the refrigerant pipe (21) is connected to the refrigerant pipe (21) between the condenser (32) and the check valve (2b). The bypass passage (23) is provided with a defrosting expansion valve (2c) having an adjustable opening degree that opens during the defrosting operation.

    The said internal unit (12) comprises the load apparatus provided with the evaporator (50), the expansion valve (51), and the drain pan coil (52). The evaporator (50), the expansion valve (51), and the drain pan coil (52) are sequentially connected by a refrigerant pipe (21).

    The evaporator (50) is constituted by, for example, a cross fin type fin-and-tube heat exchanger, and is provided with an evaporator fan (50F). One end of the evaporator (50) on the gas side is connected to the gas side communication pipe (14) via the gas side refrigerant pipe (21), and the other end on the liquid side is connected to the liquid side refrigerant pipe (21 ) To one end of the drain pan coil (52).

    Although not shown, the drain pan coil (52) is provided in the drain pan of the evaporator (50) and constitutes a heating unit that heats the drain pan with liquid refrigerant. The other end of the drain pan coil (52) The refrigerant pipe (21) is connected to the liquid side communication pipe (13).

    The expansion valve (51) constitutes an expansion mechanism that depressurizes the refrigerant during the cooling operation, is constituted by a temperature-sensitive expansion valve, and is a liquid-side refrigerant pipe that connects the evaporator (50) and the drain pan coil (52). (21) is provided.

    The refrigerant circuit (20) includes the compressor (30), the four-way switching valve (31), the condenser (32), the receiver (33), and the supercooling heat exchanger (40) of the external unit (11). ), The evaporator (50), the expansion valve (51), and the drain pan coil (52) of the internal unit (12).

    Various sensors are provided in the refrigerant circuit (20). The discharge side of the compressor (30) includes a discharge pipe temperature sensor (60) for detecting the discharge pipe temperature of the compressor (30), and a high pressure sensor (61) for detecting the discharge refrigerant pressure of the compressor (30). ) And are provided. The condenser (32) is provided with an outside sensor (62) for detecting the outside air temperature. The evaporator (50) is provided with an internal sensor (63) for detecting the internal air temperature.

    Further, a first temperature sensor (64) is provided at one end of the drain pan coil (52), and a second temperature sensor (65) is provided at the evaporator (50). The first temperature sensor (64) is configured to detect the refrigerant temperature at the outlet of the drain pan coil (52) during the defrosting operation and detect the refrigerant temperature at the inlet of the drain pan coil (52) during the cooling operation. The 1st temperature detection part is comprised.

    The second temperature sensor (65) is configured to detect the temperature of the evaporator (50) during the defrosting operation, and constitutes a second temperature detection unit. Specifically, although not shown, the evaporator (50) includes a plurality of refrigerant paths, and the second temperature sensor (65) is provided in one refrigerant path. And the said 2nd temperature sensor (65) is comprised so that the temperature of the heat exchanger tube of one refrigerant path may be detected.

    The refrigeration apparatus (10) is provided with a controller (70). The controller (70) is configured to control the cooling operation and the defrosting operation, and controls the capacity and the like of the compressor (30). The controller (70) includes a defrost control unit (71). For example, the defrost control unit (71) switches the four-way switching valve (31) every predetermined time to execute a reverse cycle defrost operation, and the defrost operation detected by the first temperature sensor (64). The defrosting operation is terminated based on the refrigerant temperature T1 at the outlet of the drain pan coil (52) at the time.

    Specifically, the defrost control unit (71) is configured such that the refrigerant temperature T1 at the outlet of the drain pan coil (52) during the defrost operation detected by the first temperature sensor (64) is equal to or higher than a predetermined first temperature. The defrosting operation is terminated when the heat transfer tube temperature (evaporator temperature) T2 of the evaporator (50) during the defrosting operation detected by the second temperature sensor (65) is equal to or higher than a predetermined second temperature. Has been.

    For example, the defrosting control unit (71) sets the first condition as to whether the state where the refrigerant temperature T1 is 10 ° C. or higher continues for 10 minutes or whether the refrigerant temperature T1 is 20 ° C. or higher. In addition, the defrosting control unit (71) sets as a second condition whether the state where the heat transfer tube temperature T2 is 10 ° C or higher continues for 10 minutes or whether the heat transfer tube temperature T1 is 20 ° C or higher. Yes. The defrosting control unit (71) ends the defrosting operation when both the first condition and the second condition are satisfied.

-Driving action-
Next, the operation of the refrigeration apparatus (10) will be described.

    First, the cooling operation of the refrigeration apparatus (10) will be described. In this cooling operation, the four-way switching valve (31) is switched to the solid line side in FIG. 1 to drive the compressor (30). At that time, the defrosting expansion valve (2c) is closed.

    The refrigerant discharged from the compressor (30) flows into the condenser (32) and is condensed to become a liquid refrigerant. After flowing through the receiver (33), this liquid refrigerant flows through the primary side passage (41) of the supercooling heat exchanger (40), and passes through the liquid side refrigerant pipe (21) to the in-compartment unit (12). Flowing into. A part of the liquid refrigerant in the refrigerant pipe (21) is depressurized by the supercooling expansion valve (4a) and flows through the secondary passage (42) of the supercooling heat exchanger (40), and the supercooling heat exchanger (40 ) Is cooled in the primary passage (41), while the refrigerant flowing through the secondary passage (42) returns to the compressor (30). The cooled supercooled liquid refrigerant flows through the drain pan coil (52), then is depressurized by the expansion valve (51), flows to the evaporator (50), evaporates and becomes gas refrigerant, and returns to the compressor (30). . This refrigerant circulation is repeated, and the internal air is cooled by the evaporator (50).

    In the defrosting operation of the refrigeration apparatus (10), the four-way switching valve (31) is switched to the broken line side in FIG. 2 to drive the compressor (30). At that time, the supercooling expansion valve (4a) is closed and the defrosting expansion valve (2c) is opened.

    The high-temperature refrigerant (hot gas) discharged from the compressor (30) flows into the evaporator (50) and heats the evaporator (50). The refrigerant flowing into the evaporator (50) flows through the drain pan coil (52) and heats the drain pan coil (52), then flows into the external unit (11), passes through the bypass passage (23), and passes through the condenser ( 32) and return to the compressor (30). This refrigerant circulation is repeated to defrost the frost adhering to the evaporator (50) and the drain pan coil (52).

    The defrosting operation is controlled by the defrosting control section (71), and the refrigerant temperature T1 at the outlet of the drain pan coil (52) detected by the first temperature sensor (64) becomes equal to or higher than a predetermined first temperature, and When the refrigerant temperature (evaporator temperature) T2 of the heat transfer tube of the evaporator (50) detected by the two-temperature sensor (65) becomes equal to or higher than a predetermined second temperature, the defrosting operation is terminated.

-Effect of Embodiment 1-
According to the first embodiment, since the defrosting operation is terminated based on the refrigerant temperature at the outlet of the drain pan coil (52) during the defrosting operation, the residual frost on the drainpan during the defrosting operation is surely prevented. can do. As a result, the drain pan frost can be prevented from growing during the cooling operation, so that the drain pan frost can be prevented from partially blocking the evaporator (50). Cooling failure can be reliably prevented.

    That is, since the liquid refrigerant is cooled by the supercooling heat exchanger (40) during the cooling operation, for example, the refrigerant supercooling degree can be set to 20 ° C. However, when the outside air temperature is low, the temperature of the liquid refrigerant becomes 0 ° C. or lower, so that the drain pan cannot be defrosted during the cooling operation. Therefore, since the defrosting operation is terminated based on the refrigerant temperature at the outlet of the drain pan coil (52) during the defrosting operation, the frosting of the drain pan can be reliably solved by the defrosting operation. As a result, the drain pan frost is prevented from growing during the cooling operation, and the evaporator (50) is not partially blocked by the drain pan frost.

    Further, when both the refrigerant temperature at the outlet of the drain pan coil (52) during the defrosting operation and the heat transfer tube temperature (evaporator temperature) of the evaporator (50) during the defrosting operation reach a predetermined temperature, the defrosting operation is performed. Therefore, it is possible to reliably prevent the residual frost in both the evaporator (50) and the drain pan during the defrosting operation.

    In particular, when the second temperature sensor (65) is provided in one refrigerant path of the evaporator (50), the second temperature sensor (65) can be provided in a refrigerant path in which frost is not easily melted. As a result, the defrosting of the evaporator (50) can be reliably performed.

-Modification of Embodiment 1-
In the first embodiment, during the defrosting operation, the refrigerant temperature T1 at the outlet of the drain pan coil (52) detected by the first temperature sensor (64) is equal to or higher than a predetermined first temperature, and the second temperature sensor (65 When the heat transfer tube temperature (evaporator temperature) T2 of the evaporator (50) detected by) becomes equal to or higher than a predetermined second temperature, the defrosting operation is terminated.

    The defrosting control unit (71) may end the defrosting operation only by the refrigerant temperature T1 at the outlet of the drain pan coil (52) detected by the first temperature sensor (64). That is, when the refrigerant temperature T1 at the outlet of the drain pan coil (52) detected by the first temperature sensor (64) becomes equal to or higher than the predetermined first temperature, the defrost control unit (71) ends the defrosting operation. .

<Embodiment 2 of the invention>
Next, a second embodiment of the present invention will be described in detail based on the drawings.

    In the present embodiment, the expansion valve (51) is configured with an electronic expansion valve in place of the expansion valve (51) configured with a temperature-sensitive expansion valve in the first embodiment.

    Further, as shown in FIG. 3, the evaporator (50) is provided with a third temperature sensor (66) and a fourth temperature sensor (67), while the controller (70) has a defrost control unit ( In addition to 71), a valve controller (72) is provided.

    As shown in FIG. 4, the evaporator (50) includes an evaporator main body (53), and a flow divider (54) and a header (55) provided in the evaporator main body (53). The flow divider (54) includes one main pipe (5a), a flow dividing section (5b) formed in the main pipe (5a), and a plurality of branch pipes (5c) branched from the flow dividing section (5b). It has. The main pipe (5a) is connected to the refrigerant pipe (21) on the liquid side, and the branch pipes (5c) are connected to the refrigerant paths of the evaporator (50).

    The header (55) includes a plurality of branch pipes (5d), a collection part (5e) that collects the plurality of branch pipes (5d), and a main pipe (5f) connected to the lower end of the collection part (5e). ). Each branch pipe (5d) is connected to each refrigerant path of the evaporator (50), and the main pipe (5f) is connected to a refrigerant pipe (21) on the gas side.

    The third temperature sensor (66) is provided in one branch pipe (5c) of the flow divider (54), and is configured to detect the temperature of the refrigerant flowing through the branch pipe (5c). Specifically, the third temperature sensor (66) detects the temperature of the refrigerant flowing into the evaporator (50) during the cooling operation, that is, the evaporation temperature of the refrigerant in the evaporator (50), and at the time of the defrosting operation. The refrigerant temperature of the evaporator (50), that is, the evaporator temperature during the defrosting operation is detected. The said 3rd temperature sensor (66) comprises the 3rd temperature detection part. The third temperature sensor (66) may be attached to the heat transfer tube of one refrigerant path.

    The fourth temperature sensor (67) is attached to the main pipe (5f) of the header (55) and is configured to detect the temperature of the refrigerant flowing through the main pipe (5f). Specifically, the fourth temperature sensor (67) is configured to detect the refrigerant temperature flowing out of the evaporator (50) during the cooling operation, that is, the refrigerant temperature at the outlet of the evaporator (50). The fourth temperature sensor (67) constitutes a fourth temperature detector.

    The valve control unit (72) includes the refrigerant evaporation temperature of the evaporator (50) during the cooling operation detected by the third temperature sensor (66) and the evaporator during the cooling operation detected by the fourth temperature sensor (67). The opening degree of the expansion valve (51) is controlled so that the refrigerant superheat degree based on the outlet refrigerant temperature of (50) becomes a predetermined value.

    On the other hand, the defrost control section (71) of the controller (70) has a refrigerant temperature T1 at the outlet of the drain pan coil (52) detected by the first temperature sensor (64) equal to or higher than a predetermined first temperature, and When the refrigerant temperature (evaporator temperature) T3 of the evaporator (50) during the defrosting operation detected by the three temperature sensor (66) becomes equal to or higher than a predetermined third temperature, the defrosting operation is terminated. .

    For example, the defrosting control unit (71) sets the first condition as to whether the state where the refrigerant temperature T1 is 10 ° C. or higher continues for 10 minutes or whether the refrigerant temperature T1 is 20 ° C. or higher. In addition, the defrosting control unit (71) sets whether the state where the refrigerant temperature T3 is 10 ° C. or higher continues for 10 minutes, or whether the refrigerant temperature T3 is 20 ° C. or higher. The defrosting control unit (71) ends the defrosting operation when both the first condition and the second condition are satisfied. Other configurations are the same as those of the first embodiment.

-Driving action-
Next, the driving operation will be described. First, in the cooling operation, the refrigerant circulates as in the first embodiment. At that time, the valve control unit (72) detects the refrigerant evaporation temperature of the evaporator (50) during the cooling operation detected by the third temperature sensor (66) and the cooling operation detected by the fourth temperature sensor (67). The opening degree of the expansion valve (51) is controlled so that the refrigerant superheat degree based on the refrigerant temperature at the outlet of the evaporator (50) at the time becomes a predetermined value.

    On the other hand, in the defrosting operation, the refrigerant circulates as in the first embodiment. At that time, the defrosting operation is controlled by the defrosting control unit (71), and the refrigerant temperature T1 at the outlet of the drain pan coil (52) detected by the first temperature sensor (64) becomes equal to or higher than a predetermined first temperature, And if refrigerant temperature (evaporator temperature) T3 of the evaporator (50) which a 3rd temperature sensor (66) detects becomes more than predetermined 3rd temperature, a defrost operation will be complete | finished. Other operations are the same as in the first embodiment.

-Effect of Embodiment 2-
According to the present embodiment, the defrost control unit (71) controls the end of the defrosting operation using the temperature detected by the third temperature sensor (66) for controlling the expansion valve (51). The temperature sensor (66) can be used to control the opening of the expansion valve (51) and the end control of the defrosting operation, and accurately determines the presence or absence of residual frost in the evaporator (50) without increasing the number of parts. can do.

    Further, when both the refrigerant temperature at the outlet of the drain pan coil (52) during the defrosting operation and the refrigerant temperature (evaporator temperature) of the evaporator (50) during the defrosting operation reach a predetermined temperature, the defrosting operation is performed. Since it was made to complete | finish, the residual frost of both the evaporator (50) at the time of a defrost operation and a drain pan can be prevented reliably. Other effects are the same as in the first embodiment.

Embodiment 3 of the Invention
Next, Embodiment 3 of the present invention will be described in detail based on the drawings.

    In the present embodiment, instead of only the drain pan coil (52) provided in the first embodiment, an electric heater (80) is provided in the drain pan (56) as shown in FIG.

    Specifically, the electric heater (80) is provided on the bottom plate of the drain pan (56) inside the drain pan (56) of the evaporator (50), and is configured to heat the drain pan (56). Yes. Note that a drain pipe (57) is connected to the drain port (58) of the drain pan (56).

    On the other hand, the controller (70) is provided with a heating controller (73) for controlling the electric heater (80). The heating controller (73) is configured to operate the electric heater (80) when the refrigerant temperature at the inlet of the drain pan coil (52) during the cooling operation decreases to a predetermined low temperature. Specifically, when the refrigerant temperature at the inlet of the drain pan coil (52) during the cooling operation detected by the first temperature sensor (64) is equal to or lower than a predetermined temperature, for example, 10 ° C or lower, the heating control unit (73) When the electric heater (80) is operated and becomes higher than a predetermined temperature, for example, when it exceeds 10 ° C., the electric heater (80) is stopped.

    That is, when the refrigerant temperature at the inlet of the drain pan coil (52) becomes 10 ° C. or less, for example, the drain pan (56) cannot be heated with the refrigerant, so the heating control unit (73) operates the electric heater (80). Let On the other hand, if the refrigerant temperature at the inlet of the drain pan coil (52) exceeds, for example, 10 ° C. and the electric heater (80) is continuously operated, the inside of the refrigerator is heated, so the heating control unit (73 ) Stop the electric heater (80).

    Therefore, since the electric heater (80) is provided, the drain pan (56) can be heated during the cooling operation, and the residual frost of the drain pan (56) can be reliably prevented. Other configurations, functions, and effects of the defrost control unit (71) are the same as those in the first embodiment. In addition, you may provide the electric heater (80) and heating control part (73) of this embodiment in Embodiment 2. FIG.

<Embodiment 4 of the Invention>
Next, a fourth embodiment of the present invention will be described in detail based on the drawings.

    In the present embodiment, the electric heater (80) is replaced with a drain pipe heater (81) as shown in FIGS. 6 and 7 instead of the electric heater (80) of the drain pan (56) in the third embodiment. ).

    The drain pipe heater (81) includes an annular part (8a) for heating the periphery of the drain port (58) of the drain pan (56), and an extension part (8b) for heating the drain pipe (57) of the drain pan (56). And is composed of a rubber belt heater. Then, the drain pipe heater (81) is operated when the refrigerant temperature at the inlet of the drain pan coil (52) at the time of the cooling operation is a predetermined temperature or lower, for example, 10 ° C. or lower, as in the third embodiment. When it becomes higher, for example, when it exceeds 10 ° C., it is stopped.

    Therefore, since the drain pan (56) can be heated using the drain pipe heater (81), the drain pipe heater for heating only the drain pipe (57) can be omitted, and the number of parts can be reduced. Can do. Other configurations, functions, and effects of the defrost control unit (71) are the same as those in the third embodiment.

<Other embodiments>
The present invention may be configured as follows for each of the above embodiments.

    The refrigerant filled in the refrigerant circuit (20) is not limited to R410A, and various refrigerants may be applied.

    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 refrigeration apparatus that performs defrosting of an evaporator in a reverse cycle.

DESCRIPTION OF SYMBOLS 10 Refrigerating device 20 Refrigerant circuit 30 Compressor 31 Four-way selector valve 32 Condenser 40 Supercooling heat exchanger 50 Evaporator 51 Expansion valve 52 Drain pan coil 56 Drain pan 57 Drain pipe 58 Drain port 64-67 Temperature sensor 70 Controller 71 Defrosting Control unit 72 Valve control unit 73 Heating control unit

Claims (7)

A compressor (30), a condenser (32), an expansion mechanism (51), and an evaporator (50) are connected in order, and a cooling operation in a positive cycle in which the refrigerant is evaporated by the evaporator (50), and the compressor A reversible refrigerant circuit (20) for refrigerant circulation, which is performed by switching between a reverse cycle defrosting operation for supplying the discharged refrigerant of (30) to the evaporator (50),
A supercooler (40) for supercooling the liquid refrigerant condensed in the condenser (32) during the cooling operation,
A heating unit (52) provided between the condenser (32) and the expansion mechanism (51) of the refrigerant circuit (20) and heating the drain pan of the evaporator (50) by the liquid refrigerant during the cooling operation; A refrigeration apparatus comprising:
A first temperature detection unit (64) for detecting the refrigerant temperature at the outlet of the heating unit (52) during the defrosting operation;
A refrigeration apparatus comprising: a defrosting control unit (71) configured to end the defrosting operation based on the refrigerant temperature detected by the first temperature detection unit (64). In claim 1,
A second temperature detector (65) for detecting the temperature of the evaporator (50) during the defrosting operation;
The defrost control unit (71) is configured such that the refrigerant temperature detected by the first temperature detection unit (64) rises above a predetermined first temperature and the evaporator temperature detected by the second temperature detection unit (65) is predetermined. The refrigeration apparatus is configured to terminate the defrosting operation when the temperature rises above the second temperature. In claim 2,
The evaporator (50) includes a plurality of refrigerant paths,
The said 2nd temperature detection part (65) is provided in one refrigerant path of an evaporator (50), The freezing apparatus characterized by the above-mentioned. In claim 1,
The expansion mechanism (51) is composed of an electronic expansion valve (51) whose opening degree can be adjusted,
A third temperature detector (66) for detecting the evaporation temperature of the refrigerant in the evaporator (50) during the cooling operation;
A fourth temperature detector (67) for detecting the refrigerant temperature at the outlet of the evaporator (50) during the cooling operation;
The opening degree of the expansion valve (51) so that the refrigerant superheat degree based on the evaporation temperature detected by the third temperature detection unit (66) and the refrigerant temperature detected by the fourth temperature detection unit (67) becomes a predetermined value. A valve control unit (72) for controlling
The defrost control unit (71) detects the refrigerant temperature detected by the first temperature detection unit (64) above a predetermined first temperature and detected by the third temperature detection unit (66) during the defrost operation. A refrigeration apparatus configured to terminate the defrosting operation when the temperature rises above a predetermined third temperature. In claim 4,
The evaporator (50) includes a plurality of refrigerant paths,
The third temperature detection unit (66) is provided in one refrigerant path of the evaporator (50). In any one of Claims 1-5,
An electric heater (80) for heating the drain pan (56);
A refrigeration system comprising: a heating control unit (73) that operates the electric heater (80) when the refrigerant temperature at the inlet of the heating unit (52) during the cooling operation is lowered to a predetermined low temperature. apparatus. In claim 6,
The electric heater (80) includes a drain pipe heater (81) that heats the drain port (58) of the drain pan (56) and the drain pipe (57).

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