JP2011169558A - Refrigerating machine for transportation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain intended capacity during heating/defrosting operation and cooling operation. <P>SOLUTION: In this refrigerating machine 1 for transportation, a vehicle 100 includes: a compressor 2 sucking and compressing a gas refrigerant; a first heat exchanger 3 provided outside a freezer 101 and condensing the high-pressure gas refrigerant made to pass through the compressor 2; a restricting mechanism 4 decompressing and expanding the liquid refrigerant made to pass through the first heat exchanger 3; a second heat exchanger 5 provided within the freezer 101 and evaporating the low-temperature liquid refrigerant made to pass through the restricting mechanism 4; refrigerant piping 7 interconnecting the devices and circulating the refrigerant; hot gas bypass piping 8 connected from the discharge side of the compressor 2 to the upstream side of the second heat exchanger 5; and a hot gas bypass on-off valve 9 opening/closing the hot gas bypass piping 8. The refrigerant machine 1 for transportation includes a third heat exchanger 6 exchanging heat between the refrigerant made to flow in the refrigerant piping 7 arranged between the downstream side of the second heat exchanger 5 and the suction side of the compressor 2 and hot water made to circulate in hot water piping 10 connected to an engine 102 of the vehicle 100. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transport refrigerator applied to a freezer mounted on a transport means such as a vehicle.

  A transport refrigerator maintains the internal temperature of a freezer mounted on a transportation means such as a vehicle at a desired temperature by performing a cooling operation and a heating operation.

  Conventionally, this type of transport refrigerator is a compressor that sucks and compresses a gas refrigerant, a condenser that condenses the high-pressure gas refrigerant that has passed through the compressor, and a high-temperature and high-pressure liquid refrigerant that has passed through the external heat exchanger is decompressed and expanded. A refrigeration cycle in which a low-temperature liquid refrigerant that has passed through the throttle mechanism is evaporated, and a refrigerant pipe that sequentially connects these with a refrigerant pipe, and a refrigerant circuit that circulates the refrigerant and repeats a state change is provided. Yes. Thereby, the transport refrigerator performs the cooling operation by circulating the refrigerant in the refrigerant circuit. On the other hand, the transport refrigerator includes a bypass circuit that directly guides a high-temperature and high-pressure gas refrigerant (hot gas) from the discharge side of the compressor to the upstream side of the internal heat exchanger. As a result, the transport refrigerator supplies a hot gas to the evaporator via a bypass circuit to perform a heating operation or a defrost operation (an operation for melting frost attached to the evaporator) (for example, see Patent Document 1).

JP 2003-322437 A

  However, in the above-described conventional transport refrigerator, part of the liquid refrigerant is returned to the compressor due to a lack of heat input to the refrigerant during the heating operation and the defrost operation, which places a burden on the compressor. Therefore, conventionally, measures have been taken to reduce the amount of hot gas supplied to the evaporator in order to reduce the burden on the compressor. For this reason, the capability of heating and defrosting is reduced. Further, in the above-described conventional transport refrigerator, during the cooling operation, for example, when the outside temperature is remarkably low and the amount of heat dissipated by the condenser is excessive with respect to the amount of heat absorbed by the evaporator, the balance of the cooling operation cycle is Is damaged, and a part of the liquid refrigerant is returned to the compressor, which places a burden on the compressor. Therefore, conventionally, in order to reduce the burden on the compressor, measures have been taken to significantly reduce the evaporation temperature of the evaporator. For this reason, cooling capacity falls.

  The present invention solves the above-described problems, and an object thereof is to provide a transport refrigerator that can maintain a desired capacity during a heating operation, a defrost operation, and a cooling operation.

  In order to achieve the above object, a transport refrigerator of the present invention includes a compressor that sucks and compresses a gas refrigerant, and a first heat that is provided outside the freezer and that condenses the high-pressure gas refrigerant that has passed through the compressor. An exchanger, a throttle mechanism that decompresses and expands the liquid refrigerant that has passed through the first heat exchanger, a second heat exchanger that is provided inside the freezer and evaporates the low-temperature liquid refrigerant that has passed through the throttle mechanism, and these A refrigerant pipe for circulating refrigerant, a hot gas bypass pipe connected from the discharge side of the compressor to an upstream side of the second heat exchanger, and a hot gas on-off valve for opening and closing the hot gas bypass pipe In the transporting refrigerator installed in the transport means, the refrigerant flowing through the refrigerant pipe disposed between the downstream side of the second heat exchanger and the suction side of the compressor, and on the transport means side Circulate with connected hot water piping Characterized by comprising a third heat exchanger for exchanging heat between that hot water.

  According to this transport refrigerator, by providing the third heat exchanger, heat is supplied to the liquid refrigerant condensed in the second heat exchanger during the heating / defrost operation, and the compressor becomes a gas refrigerant. Therefore, the desired capacity of heating / defrosting by the second heat exchanger can be maintained while reducing the burden on the compressor. Furthermore, according to this transport refrigerator, by providing the third heat exchanger, further heat is supplied to the refrigerant evaporated in the second heat exchanger during the cooling operation, and the compressor becomes a gas refrigerant. Therefore, the desired capacity of cooling by the second heat exchanger can be maintained while reducing the burden on the compressor.

  Moreover, in the transport refrigerator of the present invention, a hot water bypass pipe that circulates the hot water through the hot water pipe without passing through the third heat exchanger, and a hot water flow rate that adjusts a flow rate of the hot water to the hot water bypass pipe And adjusting means.

  According to this transport refrigerator, since the flow of hot water to the third heat exchanger can be opened and closed, or the flow rate of the hot water to the third heat exchanger can be increased or decreased, the second heat exchanger required in each cycle The operation according to the endothermic amount at can be performed.

  In the transport refrigerator of the present invention, refrigerant pressure detection means for detecting refrigerant pressure in the refrigerant pipe between the third heat exchanger and the compressor, the third heat exchanger, and the compressor A refrigerant temperature detecting means for detecting the refrigerant temperature in the refrigerant pipe between the refrigerant and the refrigerant, and storing the target refrigerant superheat degree in advance and inputting the refrigerant temperature from the refrigerant temperature detecting means according to the refrigerant pressure inputted from the refrigerant pressure detecting means Control means for controlling the hot water flow rate adjusting means in such a manner that the temperature is set to the refrigerant temperature at which the target refrigerant superheat degree is obtained.

  According to this transport refrigerator, by controlling the refrigerant superheat degree to the refrigerant temperature according to the refrigerant pressure, while ensuring the prevention of liquid refrigerant inflow to the compressor, during heating operation and defrost operation, and The desired capacity during the cooling operation can be maintained. Moreover, by setting the degree of refrigerant superheat as a target, the heating circuit of the third heat exchanger required in the heating / defrosting operation cycle and the cooling operation cycle does not require complicated calculation, and the refrigerant circuit can be used without excess or deficiency. Can be granted.

  In the transport refrigerator of the present invention, a refrigerant bypass pipe that circulates the refrigerant through the refrigerant pipe without going through the third heat exchanger, and a refrigerant flow rate that adjusts a flow rate of the refrigerant to the refrigerant bypass pipe And adjusting means.

  According to this transport refrigerator, since the flow of the refrigerant to the third heat exchanger can be opened and closed, or the flow rate of the refrigerant to the third heat exchanger can be increased or decreased, the second heat exchanger required in each cycle The operation according to the endothermic amount at can be performed.

  In the transport refrigerator of the present invention, the refrigerant pressure detecting means for detecting the refrigerant pressure in the refrigerant pipe between the downstream junction portion of the refrigerant bypass pipe and the compressor, and the downstream of the refrigerant bypass pipe A refrigerant temperature detecting means for detecting a refrigerant temperature in the refrigerant pipe between the side merge portion and the compressor; a target refrigerant superheat degree is stored in advance; and according to the refrigerant pressure input from the refrigerant pressure detecting means, Control means for controlling the refrigerant flow rate adjusting means in such a manner that the refrigerant temperature input from the refrigerant temperature detecting means is set to a refrigerant temperature at which the target refrigerant superheat degree is obtained.

  According to this transport refrigerator, by controlling the refrigerant superheat degree to the refrigerant temperature according to the refrigerant pressure, while ensuring the prevention of liquid refrigerant inflow to the compressor, during heating operation and defrost operation, and The desired capacity during the cooling operation can be maintained. Moreover, by setting the degree of refrigerant superheat as a target, the heating circuit of the third heat exchanger required in the heating / defrosting operation cycle and the cooling operation cycle does not require complicated calculation, and the refrigerant circuit can be used without excess or deficiency. Can be granted. Furthermore, even if the heat transfer to the refrigerant is unnecessary, the hot water circulates in the third heat exchanger, so that the hot water freezes even if the hot water is cooled to the freezing temperature or lower by any chance. The situation can be prevented.

  According to the present invention, it is possible to maintain a desired capacity during heating operation, defrosting operation, and cooling operation.

FIG. 1 is a schematic view of a transport refrigerator according to an embodiment of the present invention. FIG. 2 is a configuration diagram of the transport refrigerator according to the embodiment of the present invention. FIG. 3 is another schematic diagram of the transport refrigerator according to the embodiment of the present invention. FIG. 4 is an operation diagram at the time of heating / defrosting operation of the transport refrigerator shown in FIG. FIG. 5 is an explanatory diagram of the cycle during the heating / defrost operation shown in FIG. FIG. 6 is an operation diagram of the transport refrigerator shown in FIG. 2 during the cooling operation. FIG. 7 is an explanatory diagram of the cycle during the cooling operation shown in FIG. FIG. 8 is a configuration diagram of another example of the transport refrigerator shown in FIG. FIG. 9 is a block diagram of the control system of the transport refrigerator shown in FIG. FIG. 10 is a flowchart showing the control of the transport refrigerator shown in FIG. FIG. 11 is a configuration diagram of another example of the transport refrigerator shown in FIG. 12 is a block diagram of a control system of the transport refrigerator shown in FIG. FIG. 13 is a flowchart showing the control of the transport refrigerator shown in FIG.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic diagram of a transport refrigerator according to the present embodiment, and FIG. 2 is a configuration diagram of the transport refrigerator according to the embodiment of the present invention. As shown in FIG. 1, the transport refrigerator 1 (1A) is for cooling or heating the inside of a freezer 101 mounted on a vehicle 100 as a transport means. As shown in FIGS. 1 and 2, the transport refrigerator 1 (1A) includes a compressor 2, a first heat exchanger 3, a throttle mechanism 4, a second heat exchanger 5, and a third heat. An exchanger 6, a refrigerant pipe 7, a hot gas bypass pipe 8, and a hot gas on / off valve 9 are provided.

  The transport refrigerator 1 (1A) includes a compressor 2, a first heat exchanger 3, a throttle mechanism 4, a second heat exchanger 5, and a third heat exchanger 6 connected in this order by a refrigerant pipe 7. Thus, a refrigerant circuit for circulating the refrigerant is formed. In this refrigerant circuit, the compressor 2 sucks and compresses a gas refrigerant, and FIG. 1 shows a form driven using the power of the engine 102 of the vehicle 100. That is, in the transport refrigerator 1 (1 </ b> A) shown in FIG. 1, the compressor 2 is disposed in the vicinity of the engine room of the vehicle 100.

  The first heat exchanger 3 condenses the high-pressure gas refrigerant that has passed through the compressor 2. The first heat exchanger 3 is provided outside the freezer 101 in order to exchange heat with the outside air, and is connected to the compressor 2 by a refrigerant pipe 7a.

  The throttle mechanism 4 expands the liquid refrigerant that has passed through the first heat exchanger 3 under reduced pressure. The throttle mechanism 4 is provided outside the freezer 101 and is connected to the first heat exchanger 3 by a refrigerant pipe 7b.

  The second heat exchanger 5 evaporates the low-temperature liquid refrigerant that has passed through the throttle mechanism 4. The second heat exchanger 5 is provided inside the freezer 101 to cool or heat the inside of the freezer 101 and is connected to the expansion mechanism 4 by a refrigerant pipe 7c.

  The third heat exchanger 6 performs heat exchange between the refrigerant that reaches the compressor 2 via the second heat exchanger 5 and the hot water after cooling the engine 102 of the vehicle 100. The third heat exchanger 6 is provided outside the freezer 101 and is connected to the second heat exchanger 5 by a refrigerant pipe 7d and to the compressor 2 by a refrigerant pipe 7e. . The third heat exchanger 6 is connected to an engine 102 in the vehicle 100 and is interposed in a hot water pipe 10 that circulates cooling water (hot water) of the engine 102.

  The hot gas bypass pipe 8 sends the high-pressure gas refrigerant (hot gas) compressed by the compressor 2 to the second heat exchanger 5 without passing through the first heat exchanger 3 and the throttle mechanism 4. The hot gas bypass pipe 8 is connected to the refrigerant pipe 7 a and the refrigerant pipe 7 c in a mode in which the upstream side of the second heat exchanger 5 is connected from the discharge side of the compressor 2. The hot gas bypass pipe 8 is provided with a constricted portion 8a such as a capillary tube in the middle thereof. The hot gas on / off valve 9 is for opening and closing the hot gas bypass pipe 8.

  FIG. 3 is another schematic diagram of the transport refrigerator according to the embodiment. This transport refrigerator 1 (1B) is different from the transport refrigerator 1 (1A) shown in FIG. 1 described above in that the compressor 2 is driven without using the power of the engine 102 of the vehicle 100, and a separate motor or the like. Use the power of. In this case, since it is not necessary to arrange the compressor 2 near the engine room, the compressor 2 and the third heat exchanger 6 can be arranged so as to make the refrigerant pipe 7 and the hot water pipe 10 as short as possible. It is possible to improve the installation efficiency of 1 (1B).

  The transport refrigerator 1 (1A, 1B) configured as described above performs a heating operation, a defrost operation, or a cooling operation by opening and closing the hot gas on-off valve 9. The heating operation is an operation for heating the inside of the freezer 101 and transporting the contents accommodated in the freezer 101 in a heated state. The defrost operation is an operation for melting frost generated in the second heat exchanger 5 by the cooling operation. Since these heating operation and defrost operation are equivalent operations in the transport refrigerator 1 (1A, 1B), they are hereinafter collectively referred to as heating / defrost operation. The cooling operation is an operation for cooling the inside of the freezer 101 and transporting the contents accommodated in the freezer 101 in a cooled state.

  FIG. 4 is an operation diagram of the transport refrigerator shown in FIG. 2 during heating / defrost operation, and FIG. 5 is an explanatory diagram of a cycle during the heating / defrost operation shown in FIG. As shown in FIG. 4, in the heating / defrost operation, the hot gas on-off valve 9 is opened and the refrigerant flows through the hot gas bypass pipe 8, so that the refrigerant is compressed by the compressor 2, and then the throttle unit 8 a. Then, the heat is exchanged in the second heat exchanger 5 inside the freezer 101, and thereafter, the heat is exchanged in the third heat exchanger 6, and the heating / defrost cycle is returned to the compressor 2.

  That is, in the cycle during the heating / defrost operation, as shown in FIG. 5, the high-pressure gas refrigerant passed through the compressor 2 is depressurized (ab) and condensed in the second heat exchanger 5 to become liquid refrigerant (b -C) Evaporated in the third heat exchanger 6 to become a gas refrigerant (cd), returned to the compressor 2 and compressed (da). That is, heat is input to the refrigerant returned to the compressor 2 by the third heat exchanger 6.

  Here, since the conventional transport refrigerator does not have the third heat exchanger 6, a part of the liquid refrigerant condensed in the second heat exchanger 5 as shown by a two-dot chain line in FIG. Is returned to the compressor 2 (ca), and the compressor 2 is burdened. Conventionally, as a countermeasure, the amount of hot gas supplied to the second heat exchanger 5 is decreased (bc ′) and a gas refrigerant is supplied to the compressor 2 (c′-a). This reduces the burden on However, with this measure, the ability of heating and defrosting by the second heat exchanger 5 is reduced.

  On the other hand, in the transport refrigerator 1 (1A, 1B) of the present embodiment, by providing the third heat exchanger 6, heat is supplied to the liquid refrigerant condensed in the second heat exchanger 5. Since it is returned to the compressor 2 as a gas refrigerant, it is possible to maintain the desired heating / defrosting ability by the second heat exchanger 5 while reducing the burden on the compressor 2.

  6 is an operation diagram during the cooling operation of the transport refrigerator shown in FIG. 2, and FIG. 7 is a cycle explanatory diagram during the cooling operation shown in FIG. As shown in FIG. 6, in the cooling operation, the hot gas on-off valve 9 is closed and the refrigerant flowing through the hot gas bypass pipe 8 is stopped, so that the refrigerant is compressed by the compressor 2 and then outside the freezer 101. After the heat is exchanged by the first heat exchanger 3, the pressure is reduced by the expansion mechanism 4, the heat is then exchanged by the second heat exchanger 5 inside the freezer 101, and then the heat is further obtained by the third heat exchanger 6. It is operated in a cooling cycle that is replaced and returned to the compressor 2.

  That is, in the cycle during the cooling operation, as shown in FIG. 7, the high-pressure gas refrigerant having passed through the compressor 2 is condensed in the first heat exchanger 3 to become liquid refrigerant (ab), and depressurized by the throttle mechanism 4. (B-c), evaporated in the second heat exchanger 5 (cd), and heated in the third heat exchanger 6 and evaporated to become a gas refrigerant (de), the compressor Returned to 2 and compressed (ea). That is, heat is input to the refrigerant returned to the compressor 2 by the third heat exchanger 6.

  Here, in the conventional transport refrigerator, particularly when the temperature outside the freezer 101 is extremely low (for example, 0 ° C. or lower) and the temperature inside the freezer 101 is further lowered, it is released in the first heat exchanger 3. The amount of heat becomes excessive with respect to the amount of heat absorbed by the second heat exchanger 5, the balance of the cooling cycle is impaired, and part of the liquid refrigerant is returned to the compressor 2 as shown by the two-dot chain line in FIG. As a result (da), the compressor 2 is burdened. As a countermeasure, conventionally, the burden on the compressor 2 is reduced by significantly reducing the evaporation temperature of the second heat exchanger 5. However, with this measure, another burden is imposed on the compressor 2, that is, the pressure of the refrigerant returned to the compressor 2 is significantly reduced, that is, a part of the liquid refrigerant returning.

  On the other hand, in the transport refrigerator 1 (1A, 1B) of the present embodiment, by providing the third heat exchanger 6, heat is further input to the refrigerant evaporated in the second heat exchanger 5. Since it becomes a gas refrigerant and is returned to the compressor 2, it is possible to maintain the desired cooling capacity by the second heat exchanger 5 while reducing the burden on the compressor 2.

  FIG. 8 is a configuration diagram of another example of the transport refrigerator shown in FIG. The transport refrigerator 1 (1A, 1B) shown in FIG. 8 includes a warm water bypass pipe 11 and a warm water flow rate adjusting means 12 with respect to the transport refrigerator 1 (1A, 1B) shown in FIG.

  The hot water bypass pipe 11 connects the middle of the hot water pipe 10 and circulates the hot water through the hot water pipe 10 without going through the third heat exchanger 6.

  The warm water flow rate adjusting means 12 is for adjusting the flow rate of the warm water passing through the warm water bypass pipe 11. In the present embodiment, the warm water flow rate adjusting means 12 is configured as a three-way valve provided at a portion connected to the warm water pipe 10 on the upstream side of the warm water bypass pipe 11. That is, the hot water is circulated between the engine 102 and the third heat exchanger 6 via the hot water pipe 10 by the three-way valve, and the hot water is supplied only to the engine 102 via the hot water bypass pipe 11 via the hot water pipe 10. The third heat exchanger 6 by circulating hot water between the engine 102 and the third heat exchanger 6 via the hot water pipe 10 and circulating hot water through the hot water bypass pipe 11 at the same time. The form which increases / decreases the flow volume of the warm water to pass through is obtained. The hot water flow rate adjusting means 12 is not limited to the above-described three-way valve, and any flow rate adjusting valve provided in the hot water bypass pipe 11 or flow rate adjusting valve provided in the hot water pipe 10 as long as the above-described embodiments can be obtained. Alternatively, a three-way valve may be provided at a site connected to the hot water pipe 10 on the downstream side of the hot water bypass pipe 11.

  Thus, according to the transport refrigerator 1 (1A, 1B) of the present embodiment, the warm water to the third heat exchanger 6 is provided by including the warm water bypass pipe 11 and the warm water flow rate adjusting means 12. Can be opened / closed or the flow rate of the hot water to the third heat exchanger 6 can be increased / decreased, so that it is possible to perform an operation in accordance with the amount of heat absorbed in the second heat exchanger 5 required in each cycle. . Specifically, in the heating / defrost operation, it is possible to adjust the amount of increase in enthalpy in (cd) of FIG. 5 by increasing or decreasing the flow rate of hot water passing through the third heat exchanger 6. . Furthermore, when heating in the third heat exchanger 6 is not required in the heating / defrost operation, the consumption power of the compressor 2 can be reduced by stopping the hot water passing through the third heat exchanger 6. It becomes possible. In the cooling operation, it is possible to adjust the amount of enthalpy increase in (d-e) of FIG. 7 by increasing or decreasing the flow rate of the hot water passing through the third heat exchanger 6. Furthermore, in the cooling operation, when heating in the third heat exchanger 6 is not required (for example, the heat radiation amount in the first heat exchanger 3 does not become excessive with respect to the heat absorption amount in the second heat exchanger 5). In the case), the consumption power of the compressor 2 can be reduced by stopping the hot water passing through the third heat exchanger 6.

  In addition, the transport refrigerator 1 (1A, 1B) shown in FIG. 8 is upstream of the third heat exchanger 6 at two locations along the pipe with respect to the existing pipe for circulating the cooling water of the engine 102. Since only a part of the existing piping can be used as the hot water bypass piping 11 simply by connecting the end portions of the hot water piping 10 on the downstream side, the existing piping can be used effectively.

  FIG. 9 is a block diagram of the control system of the transport refrigerator shown in FIG. The transport refrigerator 1 (1A, 1B) shown in FIG. 9 is different from the transport refrigerator 1 (1A, 1B) shown in FIG. 8 in that the refrigerant pressure detection means 13, the refrigerant temperature detection means 14, and the control means 15 And.

  The refrigerant pressure detecting means 13 detects the refrigerant pressure in the refrigerant pipe 7e between the third heat exchanger 6 and the compressor 2.

  The refrigerant temperature detecting means 14 detects the refrigerant temperature in the refrigerant pipe 7e between the third heat exchanger 6 and the compressor 2.

  The control means 15 is constituted by a microcomputer or the like. The control means 15 is composed of a RAM, a ROM, etc., and is provided with a storage unit (not shown) in which programs and data are stored. The data stored in the storage unit is the target refrigerant superheat degree. The target refrigerant superheat degree is a target value of the superheat degree at which the liquid refrigerant is not returned to the compressor 2 during the operation of the transport refrigerator 1 (1A, 1B). The control means 15 is connected to a drive unit (motor) of the hot water flow rate adjustment means 12. This control means 15 is based on the input values from the refrigerant pressure detection means 13 and the refrigerant temperature detection means 14, and according to the refrigerant pressure input from the refrigerant pressure detection means 13 according to the program and data stored in the storage unit, The hot water flow rate adjusting means 12 is controlled in such a manner that the refrigerant temperature input from the detection means 14 is set to the refrigerant temperature that becomes the target refrigerant superheat degree.

  The control by the control means 15 is demonstrated with reference to the flowchart of FIG.

  As shown in FIG. 10, first, the control means 15 inputs the refrigerant pressure from the refrigerant pressure detection means 13 (step S1). Next, the control means 15 acquires the refrigerant | coolant temperature used as the target superheat degree according to the inputted refrigerant | coolant pressure (step S2). Next, the control means 15 inputs the refrigerant temperature from the refrigerant temperature detection means 14 (step S3). Next, the refrigerant temperature acquired in step S2 is compared with the refrigerant temperature input in step S3, and if both refrigerant temperatures are the same (step S4: Yes), the control means 15 ends this control. .

  In step S4, when the refrigerant temperature obtained in step S2 is compared with the refrigerant temperature input in step S3 and the refrigerant temperatures are not the same (step S4: No), the control means 15 adjusts the hot water flow rate. The means 12 is controlled (step S5). Specifically, when the refrigerant temperature input in step S3 is lower than the refrigerant temperature acquired in step S2, control is performed to increase the flow rate of hot water passing through the third heat exchanger 6. On the other hand, when the refrigerant | coolant temperature input by step S3 is higher than the refrigerant | coolant temperature acquired by step S2, control which decreases the flow volume of the warm water which passes the 3rd heat exchanger 6 is performed. Next, the control means 15 returns to step S3, inputs the refrigerant temperature from the refrigerant temperature detection means 14, and the hot water flow rate until the refrigerant temperature acquired in step S2 is the same as the refrigerant temperature input in step S3. The adjusting means 12 is controlled.

  And the control means 15 repeats this control and always monitors the transport refrigerator 1 (1A, 1B) in operation.

  Thus, according to the transport refrigerator 1 (1A, 1B) of the present embodiment, by controlling the refrigerant superheat degree to the refrigerant temperature according to the refrigerant pressure, the liquid refrigerant to the compressor 2 is controlled. It is possible to maintain a desired capacity during heating operation, defrost operation, and cooling operation while ensuring inflow prevention. In addition, by setting the degree of refrigerant superheat as a target, the amount of heating of the third heat exchanger 6 required in the heating / defrosting operation cycle and the cooling operation cycle does not require complicated calculation, and the refrigerant can be used without excess or deficiency. It can be applied to the circuit.

  FIG. 11 is a configuration diagram of another example of the transport refrigerator shown in FIG. The transport refrigerator 1 (1A, 1B) shown in FIG. 11 includes a refrigerant bypass pipe 16 and a refrigerant flow rate adjusting means 17 with respect to the transport refrigerator 1 (1A, 1B) shown in FIG.

  The refrigerant bypass pipe 16 connects a refrigerant pipe 7d that connects the second heat exchanger 5 and the third heat exchanger 6, and a refrigerant pipe 7e that connects the third heat exchanger 6 and the compressor 2, The refrigerant is circulated through the refrigerant pipe 7 without going through the third heat exchanger 6.

  The refrigerant flow rate adjusting means 17 adjusts the flow rate of the refrigerant passing through the refrigerant bypass pipe 16. In the present embodiment, the refrigerant flow rate adjusting means 17 is configured as a three-way valve provided at a site connected to the refrigerant pipe 7 d on the upstream side of the refrigerant bypass pipe 16. That is, a mode in which the refrigerant is circulated through the third heat exchanger 6 by a three-way valve, a mode in which the refrigerant is circulated through the refrigerant bypass pipe 16 without going through the third heat exchanger 6, and a third heat exchange The form which increases / decreases the flow volume of the refrigerant | coolant which passes the 3rd heat exchanger 6 which distribute | circulates a refrigerant | coolant to the condenser 6 and the refrigerant | coolant bypass piping 16 is obtained. The refrigerant flow rate adjusting means 17 is not limited to the above three-way valve, and the position to be provided is not limited to the above position as long as the above-described forms can be obtained. It is not limited to the above three-way valve, and may be a flow rate adjusting valve provided in the refrigerant bypass pipe 16, a flow rate adjusting valve provided in the refrigerant pipes 7d and 7e while the refrigerant bypass pipe 16 is connected, or You may provide a three-way valve in the site | part connected to the refrigerant | coolant piping 7e of the downstream of the refrigerant | coolant bypass piping 16. FIG.

  Thus, according to the transport refrigerator 1 (1A, 1B) of the present embodiment, the refrigerant to the third heat exchanger 6 is provided by including the refrigerant bypass pipe 16 and the refrigerant flow rate adjusting means 17. Can be opened / closed or the flow rate of the refrigerant to the third heat exchanger 6 can be increased / decreased, so that it is possible to perform an operation in accordance with the amount of heat absorbed in the second heat exchanger 5 required in each cycle. . Specifically, in the heating / defrost operation, the position of (d) in FIG. 5 can be adjusted by increasing or decreasing the flow rate of the refrigerant passing through the third heat exchanger 6. Furthermore, in the heating / defrost operation, when heating in the third heat exchanger 6 is not required, the pressure loss of the compressor 2 is reduced by stopping the refrigerant passing through the third heat exchanger 6, The power consumption of the compressor 2 can be reduced. Further, in the cooling operation, the position of (e) in FIG. 7 can be adjusted by increasing or decreasing the flow rate of the refrigerant passing through the third heat exchanger 6. Furthermore, in the cooling operation, when heating in the third heat exchanger 6 is not required (for example, the heat radiation amount in the first heat exchanger 3 does not become excessive with respect to the heat absorption amount in the second heat exchanger 5). In the case), by stopping the refrigerant passing through the third heat exchanger 6, it is possible to reduce the pressure loss of the compressor 2 and reduce the power consumption of the compressor 2.

  12 is a block diagram of a control system of the transport refrigerator shown in FIG. The transport refrigerator 1 (1A, 1B) shown in FIG. 12 is different from the transport refrigerator 1 (1A, 1B) shown in FIG. 11 in that the refrigerant pressure detection means 18, the refrigerant temperature detection means 19, and the control means 20 And.

  The refrigerant pressure detection means 18 is a refrigerant pipe 7 e between the third heat exchanger 6 and the compressor 2, and is a refrigerant in the refrigerant pipe 7 e between the downstream joint portion of the refrigerant bypass pipe 16 and the compressor 2. The pressure is detected.

  The refrigerant temperature detecting means 19 is a refrigerant pipe 7 e between the third heat exchanger 6 and the compressor 2, and is a refrigerant in the refrigerant pipe 7 e between the downstream junction portion of the refrigerant bypass pipe 16 and the compressor 2. It detects temperature.

  The control means 20 is constituted by a microcomputer or the like. The control means 20 is composed of a RAM, a ROM, etc., and is provided with a storage unit (not shown) in which programs and data are stored. The data stored in the storage unit is the target refrigerant superheat degree. The target refrigerant superheat degree is a target value of the superheat degree at which the liquid refrigerant is not returned to the compressor 2 during the operation of the transport refrigerator 1 (1A, 1B). The control means 20 is connected to a drive unit (motor) of the refrigerant flow rate adjusting means 17. This control means 20 is based on the input values from the refrigerant pressure detection means 18 and the refrigerant temperature detection means 19, and according to the refrigerant pressure input from the refrigerant pressure detection means 18 according to the program and data stored in the storage unit, The refrigerant flow rate adjusting means 17 is controlled in such a manner that the refrigerant temperature input from the detecting means 19 is set to the refrigerant temperature that becomes the target refrigerant superheat degree.

  Control by the control means 20 will be described with reference to the flowchart of FIG.

  As shown in FIG. 13, the control means 20 first inputs the refrigerant pressure from the refrigerant pressure detection means 18 (step S11). Next, the control means 20 acquires the refrigerant temperature which becomes the target superheat degree according to the inputted refrigerant pressure (step S12). Next, the control means 20 inputs the refrigerant temperature from the refrigerant temperature detection means 19 (step S13). Next, the refrigerant temperature acquired in step S12 and the refrigerant temperature input in step S13 are compared. If both refrigerant temperatures are the same (step S14: Yes), the control means 20 ends this control. .

  In Step S14, when the refrigerant temperature acquired in Step S12 is compared with the refrigerant temperature input in Step S13 and the refrigerant temperatures are not the same (No in Step S14), the control unit 20 adjusts the refrigerant flow rate. The means 17 is controlled (step S15). Specifically, when the refrigerant temperature input in step S13 is lower than the refrigerant temperature acquired in step S12, control is performed to increase the flow rate of the refrigerant passing through the third heat exchanger 6. On the other hand, when the refrigerant | coolant temperature input by step S13 is higher than the refrigerant | coolant temperature acquired by step S12, control which decreases the flow volume of the refrigerant | coolant which passes through the 3rd heat exchanger 6 is performed. Next, the control means 20 returns to step S13, inputs the refrigerant temperature from the refrigerant temperature detection means 19, and the refrigerant flow rate until the refrigerant temperature acquired in step S12 is the same as the refrigerant temperature input in step S13. The adjusting means 17 is controlled.

  And the control means 20 repeatedly performs this control, and always monitors the transport refrigerator 1 (1A, 1B) in operation.

  Thus, according to the transport refrigerator 1 (1A, 1B) of the present embodiment, by controlling the refrigerant superheat degree to the refrigerant temperature according to the refrigerant pressure, the liquid refrigerant to the compressor 2 is controlled. It is possible to maintain a desired capacity during heating operation, defrost operation, and cooling operation while ensuring inflow prevention. In addition, by setting the degree of refrigerant superheat as a target, the amount of heating of the third heat exchanger 6 required in the heating / defrosting operation cycle and the cooling operation cycle does not require complicated calculation, and the refrigerant can be used without excess or deficiency. It can be applied to the circuit. Furthermore, even if the heat transfer to the refrigerant is unnecessary, the hot water circulates in the third heat exchanger 6, so that even if the hot water is cooled to the freezing temperature or lower by the refrigerant, the hot water is frozen. Can be prevented.

  As described above, the transport refrigerator according to the present invention is suitable for maintaining a desired capacity during a heating operation, a defrost operation, and a cooling operation.

1 (1A, 1B) Transport refrigerator 2 Compressor 3 First heat exchanger 4 Throttle mechanism 5 Second heat exchanger 6 Third heat exchanger 7 (7a, 7b, 7c, 7d, 7e) Refrigerant piping 8 Hot Gas bypass piping 8a Restriction section 9 Hot gas on-off valve 10 Hot water piping 11 Hot water bypass piping 12 Hot water flow rate adjustment means 13, 18 Refrigerant pressure detection means 14, 19 Refrigerant temperature detection means 15, 20 Control means 16 Refrigerant bypass piping 17 Refrigerant flow rate adjustment Means 100 Vehicle (transportation means)
101 freezer 102 engine

Claims (5)

A compressor that sucks and compresses the gas refrigerant; a first heat exchanger that is provided outside the freezer and condenses the high-pressure gas refrigerant that has passed through the compressor; and the liquid refrigerant that has passed through the first heat exchanger is decompressed and expanded. A throttle mechanism; a second heat exchanger provided inside the freezer for evaporating a low-temperature liquid refrigerant that has passed through the throttle mechanism; a refrigerant pipe that connects these to circulate the refrigerant; and a discharge side of the compressor A transport refrigerator having a hot gas bypass pipe connected to the upstream side of the second heat exchanger and a hot gas on / off valve for opening and closing the hot gas bypass pipe installed in a transport means;
Between the refrigerant | coolant which distribute | circulates the said refrigerant | coolant piping arrange | positioned between the downstream of said 2nd heat exchanger and the suction side of the said compressor, and the hot water circulated in the hot water piping connected to the said transport means side A transport refrigerator comprising a third heat exchanger for exchanging heat in A hot water bypass pipe for circulating the hot water in the hot water pipe without going through the third heat exchanger;
Hot water flow rate adjusting means for adjusting the flow rate of the hot water to the hot water bypass pipe;
The transport refrigerator according to claim 1, comprising: Refrigerant pressure detection means for detecting refrigerant pressure in the refrigerant pipe between the third heat exchanger and the compressor;
Refrigerant temperature detection means for detecting refrigerant temperature in the refrigerant pipe between the third heat exchanger and the compressor;
The hot water flow rate adjustment is performed in such a manner that the target refrigerant superheat degree is stored in advance and the refrigerant temperature input from the refrigerant temperature detection means is set to the refrigerant temperature that becomes the target refrigerant superheat degree according to the refrigerant pressure input from the refrigerant pressure detection means. Control means for controlling the means;
The transport refrigerator according to claim 2, comprising: A refrigerant bypass pipe for circulating the refrigerant in the refrigerant pipe without going through the third heat exchanger;
Refrigerant flow rate adjusting means for adjusting the flow rate of the refrigerant to the refrigerant bypass pipe;
The transport refrigerator according to claim 1, comprising: A refrigerant pressure detecting means for detecting a refrigerant pressure in the refrigerant pipe between the downstream joint portion of the refrigerant bypass pipe and the compressor;
A refrigerant temperature detecting means for detecting a refrigerant temperature in the refrigerant pipe between the downstream merge portion of the refrigerant bypass pipe and the compressor;
The refrigerant flow rate adjustment is performed in such a manner that the target refrigerant superheat degree is stored in advance and the refrigerant temperature input from the refrigerant temperature detection means is set to the refrigerant temperature that becomes the target refrigerant superheat degree according to the refrigerant pressure input from the refrigerant pressure detection means. Control means for controlling the means;
The transport refrigerator according to claim 4, comprising:

Images