JP2004085106A - Refrigerator and cold storage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator and a cold storage optimum for using a cooling medium with the state varied at a super-critical region and a subcritical region at a high pressure side of a refrigerating cycle. <P>SOLUTION: The refrigerator is provided with a refrigerating cycle starting from a delivery port (16c) of a compressor (16) and returning to a flowing-in port (16d) of the compressor through an air-cooling heat exchanger (17) in which the gaseous cooling medium compressed by the compressor and becoming high temperature/high pressure is air-cooled, a high pressure side pipe (22a) of an internal heat exchanger (22), a pressure reduction device (23) and a low pressure side pipe (22b) for heat-exchanging a high pressure side pipe of the internal heat exchanger; a cooling medium amount adjustment circuit (26) with one end connected to a low pressure side cooling medium circuit of the refrigerating cycle and the other end connected to a high pressure side cooling medium circuit; a low pressure side valve (V1) provided at one end of the cooling medium amount adjustment circuit; and a high pressure side valve (V2) provided at the other end of the cooling medium amount adjustment circuit. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a refrigerator for cooling objects and a refrigerator for refrigerated storage in a refrigerator.
[0002]
[Prior art]
In a refrigerator equipped with a conventional refrigerator, the inside of the refrigerator is cooled by a cooler of the refrigerator, and stored items are stored in the refrigerator. As a refrigerant in a refrigeration cycle of a refrigerator, a Freon-based refrigerant is generally used, and is liquefied in a condenser. Therefore, in this condenser, the refrigerant has a substantially constant temperature (that is, the condensation temperature).
[0003]
[Problems to be solved by the invention]
By the way, in recent years, the use of chlorofluorocarbon-based refrigerants has been reduced, and the use of refrigerants other than chlorofluorocarbon-based refrigerants (for example, carbon dioxide) has also been studied in refrigerators. When such a refrigerant is used, the state may change in a supercritical region or a subcritical region when the refrigerant is air-cooled on the high pressure side of the refrigeration cycle. The air cooling of the refrigerant is performed by air around the refrigerator or the refrigerator (that is, the atmosphere), and the temperature of the atmosphere changes, and is high (for example, about 30 ° C.) or low (for example, about 30 ° C.). , About 10 ° C). As described above, the load condition of the refrigerator such as the air-cooled state changes, and in accordance with the load condition, the refrigerant on the high pressure side of the refrigeration cycle changes state in the supercritical region, or in the subcritical region. Or change state. In the supercritical state, the high pressure side of the refrigeration cycle is in the gas region, so that the required amount of refrigerant is small. On the other hand, in the subcritical state, the high-pressure side of the refrigeration cycle changes state to gas, gas-liquid two-phase, and liquid, so that the required amount of refrigerant is larger than that in the supercritical state. As described above, since the optimum amount of refrigerant when the state changes in the supercritical region and the optimum amount of refrigerant when the state changes in the subcritical region are different, it is necessary to appropriately adjust the amount of the refrigerant in the refrigeration cycle. .
[0004]
The present invention has been made to solve the above problems, and provides a refrigerator and a refrigerator that are optimal for using a refrigerant that changes state in a supercritical region or a subcritical region on the high pressure side of a refrigeration cycle. It is aimed at.
[0005]
[Means for Solving the Problems]
The refrigerating machine of the present invention comprises an air-cooled heat exchanger (17) for air-cooling a high-temperature and high-pressure gaseous refrigerant compressed by the compressor from a discharge port (16c) of the compressor (16), and an internal heat exchanger. Heat exchange with the high pressure side pipe (22a) of (22), the pressure reducing device (23), the cooler (24) through which the refrigerant depressurized by the pressure reducing device and having a low temperature flows, and the high pressure side pipe of the internal heat exchanger Refrigeration cycle which returns to the compressor inlet (16d) through the low pressure side pipe (22b) sequentially, and a refrigerant having one end connected to the low pressure side refrigerant circuit of the refrigeration cycle and the other end connected to the high pressure side refrigerant circuit. An amount adjustment circuit (26), a low pressure side valve (V1) provided at one end of the refrigerant amount adjustment circuit, and a high pressure side valve (V2) provided at the other end of the refrigerant amount adjustment circuit. It has.
[0006]
Further, the refrigerant may be carbon dioxide.
And the outer peripheral surface of the said refrigerant | coolant amount adjustment circuit may be joined with the outer peripheral surface of the low pressure side piping of the said internal heat exchanger.
[0007]
Further, there is a case where one end of the refrigerant amount adjusting circuit is connected to the upstream side of the low pressure side pipe of the internal heat exchanger.
Further, the other end of the refrigerant amount adjusting circuit may be connected to a downstream side of a high pressure side pipe of the internal heat exchanger.
[0008]
A cooler inlet temperature detecting means (36) for detecting a temperature on an inlet side of the cooler; a cooler outlet temperature detecting means (37) for detecting a temperature on an outlet side of the cooler; And a control device (41) for controlling the opening degree of the high-pressure side valve. The control device detects a difference between the cooler inlet / outlet temperature from the cooler inlet temperature detecting means and the cooler outlet temperature detecting means. When the difference between the inlet and outlet temperature of the cooler is large, the opening of the low pressure side valve is increased, and the opening of the high pressure side valve is reduced or closed. There may be provided a means for reducing or closing the opening of the side valve and increasing the opening of the high pressure side valve.
[0009]
In the refrigerator of the present invention, the outer shell is formed of an insulating box (1), and the front opening of the refrigerator is opened and closed by an insulating door. An air-cooled heat exchanger that air-cools high-temperature, high-pressure gaseous refrigerant, a high-pressure pipe of the internal heat exchanger, a decompression device, and a cooler that cools the inside of the refrigerator with low-temperature refrigerant depressurized by the decompression device And a refrigeration cycle that returns to the compressor inlet via a low-pressure pipe that exchanges heat with the high-pressure pipe of the internal heat exchanger, one end of the refrigeration cycle in the low-pressure refrigerant circuit, and the other end of the high-pressure refrigerant. A refrigerant amount adjusting circuit connected to the circuit, a low pressure side valve provided at one end of the refrigerant amount adjusting circuit, and a high pressure side valve provided at the other end of the refrigerant amount adjusting circuit. hand That.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a refrigerator having a refrigerator according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram of a refrigerant circuit of a refrigerator according to an embodiment of the present invention. FIG. 2 is a diagram of a specific example of the dew-prevention pipe in FIG. FIG. 3 is an input / output diagram of the control device. FIG. 4 is a sectional view of the refrigerant pipe of the internal heat exchanger. FIG. 5 is a flowchart of the operation of the high-pressure side valve and the low-pressure side valve.
[0011]
A household refrigerator provided with a refrigerator has an outer shell formed of a heat insulating box 1 (see FIG. 2). The internal space of the heat-insulating box 1, that is, the inside of the refrigerator, is partitioned into a plurality of rooms (four in this embodiment) having different set temperatures, and a refrigerator room 6, a vegetable room 7, a freezer room 8 and a freezer room from the upper side. It is room 9. The front surfaces of the cooling chambers 6 to 9 are open, and the front openings are openably closed by heat insulating doors (not shown). The back side of the freezing room 9 is a machine room.
[0012]
In the machine room, equipment of a refrigerator for cooling the inside of the refrigerator, that is, a two-stage compression type compressor 16, an air-cooling heat exchanger 17, an air-cooling heat exchanger blower 18 and the like are provided. The compressor 16 and the air-cooled heat exchanger 17 are connected by a refrigerant pipe 21 to form a refrigeration cycle, and CO ₂ (carbon dioxide) is used as a refrigerant of the refrigeration cycle. In this refrigeration cycle, as shown in FIG. 1, the compressor 16 returns from the first-stage discharge port 16 a to the second-stage inlet 16 b of the compressor 16 through the primary air-cooled heat exchange section 17 a of the air-cooled heat exchanger 17. From the first-stage cycle and from the second-stage discharge port 16c of the compressor 16, the secondary air-cooled heat exchange part 17b of the air-cooled heat exchanger 17 and the front end face of the heat insulating box 1 are sequentially piped. The first stage of the compressor 16 again from the dew-prevention pipe 19, the high-pressure side pipe 22 a of the internal heat exchanger 22, the electric expansion valve 23, the cooler 24, which is a pressure reducing device, and the low-pressure side pipe 22 b of the internal heat exchanger 22. And a second-stage cycle returning to the inflow port 16d.
[0013]
In the compressor 16, the first stage compression mechanism compresses the refrigerant flowing from the first stage inlet 16d and discharges the refrigerant through the outlet 16a, and the second stage compression mechanism switches the second stage inlet The refrigerant flowing from the outlet 16b is compressed and discharged from the outlet 16c. Further, the area from the discharge port 16c of the compressor 16 to the electric expansion valve 23 is on the high pressure side of the refrigeration cycle, and the area from the electric expansion valve 23 to the inlet 16d of the compressor 16 is on the low pressure side of the refrigeration cycle.
[0014]
One end of the refrigerant amount adjusting circuit 26 for adjusting the amount of refrigerant in the first stage cycle and the second stage cycle of the refrigeration cycle is connected to the low pressure side refrigerant circuit of the refrigeration cycle via the low pressure side valve V1 (more specifically, It is connected downstream of the cooler 24 and upstream of the low pressure side pipe 22 b of the internal heat exchanger 22. Further, the other end of the refrigerant amount adjusting circuit 26 is connected to the high pressure side refrigerant circuit of the refrigeration cycle via the high pressure side valve V2 (more specifically, downstream of the high pressure side pipe 22a of the internal heat exchanger 22 and the expansion valve). 23 upstream). As shown in FIG. 4, the outer peripheral surface of the refrigerant pipe of the refrigerant amount adjusting circuit 26 is in contact with the outer peripheral surface of the high pressure side pipe 22a of the internal heat exchanger 22 and the outer peripheral surface of the low pressure side pipe 22b of the internal heat exchanger 22. It is joined by a joining material such as soldering 31. In particular, the refrigerant amount adjusting circuit 26 is bonded to and adhered to the low-pressure side pipe 22b, and the refrigerant in the refrigerant amount adjusting circuit 26 exchanges heat with the low-temperature refrigerant in the low-pressure side pipe 22b, and the temperature decreases. Further, at the time of joining with the refrigerant amount adjusting circuit 26, the outer peripheral surface of the high-pressure side pipe 22a and the outer peripheral surface of the low-pressure side pipe 22b are also joined to each other with a joining material such as soldering 31 so that they are in close contact with each other. The relatively high-temperature refrigerant in the pipe 22a and the low-temperature refrigerant in the low-pressure pipe 22b exchange heat.
[0015]
Further, the cooler 24 has a low temperature, and lowers the temperature of the surrounding air. The cool air around the cooler 24 is blown and circulated by the fan 33 in the refrigerator to cool the refrigerator. Thus, the inside of the refrigerator can be cooled by the cooler 24. Further, a refrigerator temperature sensor 34 as a cooling chamber temperature detecting means for detecting a temperature inside the refrigerator (in this embodiment, a temperature of the freezing room 8 which is a cooling room), and a cooler for detecting the temperature on the inlet side of the cooler 24. A cooler inlet temperature sensor 36 serving as inlet temperature detecting means and a cooler outlet temperature sensor 37 serving as cooler outlet temperature detecting means for detecting the temperature at the outlet side of the cooler 24 are provided.
[0016]
As shown in FIG. 3, the refrigerator is provided with a control device 41, and the control device 41 is configured by a microcomputer or the like. Various electric components are connected to the control device 41. In particular, as an electric component for controlling the low-pressure side valve V1, the high-pressure side valve V2, and the like, the cooler inlet temperature sensor 36, The cooler outlet temperature sensor 37, the internal temperature sensor 34, and the like are connected, while the output side is connected to the low-pressure valve V1, the high-pressure valve V2, the compressor 16, and the like. Note that various setting values are stored in a storage unit (ROM, RAM, or the like) of the control device 41, and a timer (not shown) is built in. In addition, the control device 41 performs various controls (for example, temperature control in the refrigerator) in addition to the control of the low-pressure side valve V1 and the high-pressure side valve V2.
[0017]
In the refrigerator according to the embodiment configured as described above, when the compressor 16 operates, the gaseous refrigerant (CO ₂ ) is compressed in the first stage of the compressor 16 to become a high-temperature and high-pressure gaseous refrigerant, and air-cooled heat exchange. In the primary air-cooling heat exchange section 17 a of the heat exchanger 17, the air is cooled by the air from the air-cooling heat exchanger blower 18 (air in the room where the refrigerator, that is, the refrigerator is installed), the temperature is reduced, and the air returns to the compressor 16.
[0018]
Then, the refrigerant is further compressed in the second stage of the compressor 16 to become a high-temperature and high-pressure gaseous refrigerant, and is air-cooled by air from the air-cooling heat exchanger blower 18 in the secondary air-cooling heat exchanger 17 b of the air-cooling heat exchanger 17. Then, the temperature of the refrigerant decreases while changing the state in the supercritical region or the subcritical region. The cooled refrigerant flows into the dew-prevention pipe 19. As described above, the dew-prevention pipe 19 is provided along the frontage of the heat-insulating box 1. However, since the temperature of the refrigerant in the dew-prevention pipe 19 gradually decreases, the cooling chambers 6 to 9 are formed. (That is, the order of decreasing the temperature of the cooling chambers 6 to 9). In this embodiment, the freezing compartment 8 and the freezing compartment 9 have the lowest temperature at substantially the same temperature, and the cooling compartment 6 having the highest temperature in the refrigerator compartment 6 is the vegetable compartment 7. Therefore, as shown in FIG. 2, the dew-prevention pipe 19 includes, in order from the refrigerant inflow side, the right side of the freezing room 8, the right side, the lower side, the left side, the upper side of the freezing room 9, the lower side of the freezing room 8, The left side, the upper side, and then turned back, the lower side, the left side of the vegetable compartment 7, the left side, the upper side, the right side, the lower side of the refrigerator compartment 6, and then turned back, passed through the upper side, the right side of the vegetable compartment 7, to the internal heat exchanger 22. It is flowing out. In this way, the dew-prevention pipe 19 goes around the freezing compartments 8 and 9 first, then the refrigerator compartment 6 and then around the vegetable compartment 7 as much as possible.
[0019]
Next, the refrigerant that has flowed out of the dew-prevention pipe 19 is cooled by the refrigerant returned from the cooler 24 in the internal heat exchanger 22, and then depressurized through the electric expansion valve 23, which is a decompression device, to lower the temperature. I do. This low-temperature refrigerant flows into the cooler 24 and lowers the temperature of the air around the cooler 24. The air whose temperature has been lowered by the cooler 24 is circulated in the refrigerator by the fan 33 in the refrigerator, and cools the cooling chambers 6 to 9. The refrigerant flowing out of the cooler 24 exchanges heat with the refrigerant on the high pressure side in the internal heat exchanger 22 and returns to the inlet 16 d of the compressor 16 after the temperature rises.
[0020]
The control device 41 determines whether or not the inside temperature (cooling room temperature) detected by the inside temperature sensor 34 has reached the cooling room set temperature set in the storage unit of the control device 41. When the temperature is equal to or lower than the cooling room set temperature, the compressor 16 is stopped. On the other hand, when the internal temperature exceeds the cooling room set temperature, the compressor 16 is operated and the cooler 24 cools the internal space. The air-cooling heat exchanger blower 18 and the in-compartment fan 33 operate substantially in conjunction with the compressor 16 under the control of the control device 41, and start operating together with the compressor 16, and when the compressor 16 stops, there is a slight delay. Has stopped.
[0021]
By the way, when the room temperature of the room where the refrigerator is installed increases, the temperature of the refrigerant in the air-cooled heat exchanger 17 increases accordingly, and the refrigerant changes state in the supercritical region on the high pressure side of the refrigeration cycle. On the other hand, when the room temperature decreases, the temperature of the refrigerant in the air-cooled heat exchanger 17 decreases accordingly, and the refrigerant changes state in the subcritical region on the high pressure side of the refrigeration cycle. When the load conditions are different as described above, the optimum amount of the refrigerant changes. Therefore, by controlling the opening degrees of the low-pressure side valve V1 and the high-pressure side valve V2, the amount of refrigerant accumulated in the refrigerant amount adjusting circuit 26 is adjusted. For example, when the low-pressure side valve V1 is closed and the high-pressure side valve V2 is opened to increase the pressure in the refrigerant amount adjustment circuit 26, the amount of refrigerant in the refrigerant amount adjustment circuit 26 increases, and conversely, the refrigeration cycle The amount of the refrigerant flowing to is reduced.
[0022]
The control flow of the opening of the low-pressure side valve V1 and the high-pressure side valve V2 will be described with reference to the flowchart of FIG.
In step 1, when the compressor 16 operates, the process proceeds to step 2. In step 2, the control device 41 fully opens the low-pressure side valve V1, fully closes the high-pressure side valve V2, lowers the pressure in the refrigerant amount adjustment circuit 26, and increases the amount of refrigerant flowing in the refrigeration cycle. Then, go to step 3.
[0023]
In step 3, the control device 41 samples (obtains) detection values from the cooler inlet temperature sensor 36 and the cooler outlet temperature sensor 37, and calculates the cooler from the cooler outlet temperature, which is the detected value of the cooler outlet temperature sensor 37. The cooler inlet / outlet temperature difference dTE is obtained by subtracting the cooler inlet temperature detected by the inlet temperature sensor 36. Then, control device 41 compares upper set value TU (for example, 5 degrees) preset in the storage unit with cooler inlet / outlet temperature difference dTE, and cooler inlet / outlet temperature difference dTE is equal to or larger than upper set value TU. In this case, the flow returns to step 1 because the amount of the refrigerant flowing through the refrigeration cycle is insufficient. On the other hand, if the cooler inlet / outlet temperature difference dTE is smaller than the upper set value TU, the procedure goes to step 4.
[0024]
In step 4, the control device 41 compares the lower set value TL (for example, 1 degree) preset in the storage unit thereof with the cooler inlet / outlet temperature difference dTE, and determines that the cooler inlet / outlet temperature difference dTE is lower. If it is less than the set value TL, the amount of the refrigerant flowing through the refrigeration cycle is too small, so that the procedure goes to step 6. On the other hand, if the cooler inlet / outlet temperature difference dTE is equal to or greater than the lower set value TL, the flow of the refrigerant in the refrigeration cycle is likely to be insufficient, and the process proceeds to step 5.
[0025]
In step 5, the control device 41 controls the opening of the low-pressure side valve V1 to be large and the opening of the high-pressure side valve V2 to be small or closed. The opening degrees of the low-pressure side valve V1 and the high-pressure side valve V2 are each determined by a function of the cooler inlet / outlet temperature difference dTE. That is, V1 opening = f1 (dTE) V2 opening = f2 (dTE)
Then, the process returns to step 3.
[0026]
In step 6, the control device 41 controls the opening degree of the low-pressure side valve V1 to be small or closed and the opening degree of the high-pressure side valve V2 to be large. The opening degrees of the low-pressure side valve V1 and the high-pressure side valve V2 are each determined by a function of the cooler inlet / outlet temperature difference dTE. That is, V1 opening = f3 (dTE) V2 opening = f4 (dTE)
Then, the process returns to step 4.
[0027]
In this manner, (1) at the initial stage of the operation of the compressor 16 and when the cooler inlet / outlet temperature difference dTE is larger than the upper set value TU, the amount of refrigerant flowing through the refrigeration cycle is insufficient. The side valve V1 is fully opened, the high-pressure side valve V2 is fully closed, the pressure in the refrigerant amount adjustment circuit 26 is reduced, and the amount of refrigerant flowing through the refrigeration cycle is increased.
(2) When the cooler inlet / outlet temperature difference dTE is smaller than the upper set value TU and larger than the lower set value TL, the amount of the refrigerant flowing through the refrigeration cycle tends to be insufficient, and thus the low pressure side valve V1 is opened. The pressure inside the refrigerant amount adjusting circuit 26 is made slightly lower by increasing the degree of opening, and the opening degree of the high pressure side valve V2 is made smaller or closed, so that the amount of refrigerant flowing through the refrigeration cycle becomes larger.
(3) When the cooler inlet / outlet temperature difference dTE is smaller than the lower set value TL, the amount of the refrigerant flowing through the refrigeration cycle is too small, so the opening of the low-pressure side valve V1 is reduced or closed (that is, the cooling is performed). The opening / closing of the low-pressure side valve V1 is made smaller than the case where the temperature difference dTE between the container and the outlet is smaller than the upper set value TU and larger than the lower set value TL. (Ie, the opening degree of the high-pressure side valve V2 is made larger than when the cooler inlet / outlet temperature difference dTE is smaller than the upper set value TU and larger than the lower set value TL. 3.) The pressure in the refrigerant amount adjusting circuit 26 is slightly increased to reduce the amount of refrigerant flowing in the refrigeration cycle.
[0028]
As described above, in the refrigerator and the refrigerator of the embodiment, the amount of refrigerant flowing through the refrigeration cycle can be appropriately adjusted by the refrigerant amount adjustment circuit 26, and high-efficiency operation can be performed. As a result, power consumption can be reduced.
Further, the refrigerant amount adjusting circuit 26 is provided between the high pressure side refrigerant circuit and the low pressure side refrigerant circuit of the refrigeration cycle, and has an intermediate pressure. Therefore, the pressure resistance can be made relatively low, and the productivity can be improved, and the cost and the like can be reduced.
The refrigerant amount adjusting circuit 26 is cooled by the low pressure side pipe 22 b of the internal heat exchanger 22, so that the temperature of the refrigerant stored in the refrigerant amount adjusting circuit 26 can be lowered. Therefore, a large amount of refrigerant can be stored with a relatively small capacity.
Further, since the low pressure side end of the refrigerant amount adjustment circuit 26 is connected to the upstream side of the low pressure side pipe 22 b of the internal heat exchanger 22, the refrigerant from the refrigerant amount adjustment circuit 26 is supplied to the internal heat exchanger 22. Flows into the compressor 16 after having exchanged heat with the high-pressure side pipe 22a having a relatively high temperature. Therefore, it is possible to prevent the liquid refrigerant from flowing into the compressor 16 from the refrigerant amount adjustment circuit 26 as much as possible.
[0029]
As described above, the control device 41 (1) means for fully opening the low-pressure side valve V1 and fully closing the high-pressure side valve V2 when the cooler inlet / outlet temperature difference dTE is larger than the upper set value TU. (2) When the cooler inlet / outlet temperature difference dTE is smaller than the upper set value TU and larger than the lower set value TL, the opening degree of the low pressure side valve V1 is increased and the high pressure side valve V2 is increased. Means for reducing or closing the opening degree of the valve (3) When the cooler inlet / outlet temperature difference dTE is smaller than the lower set value TL, the opening degree of the low pressure side valve V1 is reduced or closed, and the high pressure side valve V2 is closed. Means for increasing the degree of opening are provided.
As described above, the control device 41 includes, in addition to the above-described means, means for executing each action corresponding to each action to be executed. Also, not all means need be provided.
[0030]
As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various modifications may be made within the scope of the present invention described in the appended claims. It is possible to do. Modification examples of the present invention are exemplified below.
(1) The refrigerant of the refrigeration cycle can be appropriately selected. However, CO ₂ is optimal.
[0031]
(2) The type and structure of the refrigerator can be appropriately selected, but it is preferably for household use, and the interior of the refrigerator is partitioned into at least three temperature zones (that is, a refrigerator room, a freezer room, and a vegetable room). . Further, the refrigerator can include not only a refrigerator but also a freezer.
(3) Although the decompression device is configured by an expansion valve, other configurations such as a capillary tube can be used.
(4) In this embodiment, the compressor is of a two-stage compression type, but may be of a one-stage compression type. In the case of the single-stage compression type, the refrigeration cycle does not include the first-stage cycle but only the second-stage cycle.
[0032]
(5) Various values are set in the storage unit of the control device 41, and the setting method and the set values can be appropriately selected. Further, the control method of the opening degree of the low-pressure side valve V1 and the high-pressure side valve V2 can be appropriately changed.
(6) The refrigerant amount adjusting circuit is provided in the internal heat exchanger, but may be provided in another place.
[0033]
【The invention's effect】
According to the present invention, one end of the refrigerant amount adjustment circuit is connected to the low pressure side refrigerant circuit of the refrigeration cycle via the low pressure side valve, and the other end is connected to the high pressure side refrigerant circuit via the high pressure side valve. By appropriately opening and closing the valve, the amount of the refrigerant flowing through the refrigeration cycle can be adjusted by storing or opening the refrigerant in the refrigerant amount adjustment circuit. Therefore, even if the state of the refrigerant changes in the supercritical region or the subcritical region on the high pressure side of the refrigeration cycle, the amount of the refrigerant flowing through the refrigeration cycle can be appropriately adjusted by the refrigerant amount adjustment circuit. As a result, the refrigerator can be operated with high efficiency, and power consumption can be reduced.
[0034]
And since the outer peripheral surface of a refrigerant | coolant amount adjustment circuit is joined to the outer peripheral surface of the low pressure side piping of an internal heat exchanger, the temperature of the refrigerant | coolant of a refrigerant | coolant amount adjustment circuit can be made low. Therefore, a large amount of refrigerant can be stored with a relatively small capacity.
[0035]
Furthermore, since one end of the refrigerant amount adjustment circuit is connected to the upstream side of the low pressure side pipe of the internal heat exchanger, the refrigerant from the refrigerant amount adjustment circuit flows through the low pressure side pipe of the internal heat exchanger, and Heat exchanges with the high-temperature high-pressure side piping before flowing into the compressor. Therefore, it is possible to prevent liquid refrigerant from flowing into the compressor from the refrigerant amount adjustment circuit as much as possible.
[0036]
Also, since the other end of the refrigerant amount adjustment circuit is connected to the downstream side of the high pressure side pipe of the internal heat exchanger, the refrigerant amount adjustment circuit exchanges heat with the low pressure side pipe of the internal heat exchanger to maintain a low temperature. The refrigerant in the high-pressure side pipe that has flowed in flows. In this way, a relatively low temperature refrigerant is stored in the refrigerant amount adjustment circuit, so that a large amount of refrigerant can be stored with a relatively small capacity.
[0037]
And, since the opening degree of the low pressure side valve and the high pressure side valve is controlled by the difference between the temperature on the inlet side and the temperature on the outlet side of the cooler, the structure is smaller than the case where the opening degree is controlled by a pressure sensor or the like. It's easy.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a refrigerant circuit of one embodiment of a refrigerator according to the present invention.
FIG. 2 is a view showing a specific example of a dew-prevention pipe in FIG. 1;
FIG. 3 is an input / output diagram of a control device.
FIG. 4 is a sectional view of a refrigerant pipe of the internal heat exchanger.
FIG. 5 is a flowchart of the operation of a high-pressure side valve and a low-pressure side valve.
[Explanation of symbols]
V1 Low-pressure side valve V2 High-pressure side valve 1 Insulated box 16 Compressor 16c Compressor outlet 16d Compressor inlet 17 Air-cooled heat exchanger 22 Internal heat exchanger 22a High-pressure side pipe 22b Low-pressure side pipe 23 Electric expansion valve (decompression device)
24 cooler 26 refrigerant amount adjustment circuit 36 cooler inlet temperature sensor (cooler inlet temperature detecting means)
37 Cooler outlet temperature sensor (cooler outlet temperature detecting means)
41 Control device

Claims (7)

An air-cooled heat exchanger, in which the gaseous refrigerant compressed to a high temperature and a high pressure by the compressor is air-cooled from the discharge port of the compressor, a high pressure side pipe of the internal heat exchanger, a decompression device, and a low pressure A refrigeration cycle that returns to the compressor inlet through a cooler through which the refrigerant that has passed, and a low-pressure pipe that exchanges heat with the high-pressure pipe of the internal heat exchanger,
One end is connected to the low-pressure side refrigerant circuit of the refrigeration cycle, and the other end is connected to the high-pressure side refrigerant circuit, a refrigerant amount adjustment circuit,
A low-pressure side valve provided at one end of the refrigerant amount adjustment circuit,
A refrigerator provided with a high-pressure side valve provided at the other end of the refrigerant amount adjusting circuit. The refrigerator according to claim 1, wherein the refrigerant is carbon dioxide. The refrigerator according to claim 1, wherein an outer peripheral surface of the refrigerant amount adjusting circuit is joined to an outer peripheral surface of a low-pressure side pipe of the internal heat exchanger. The refrigerator according to claim 1, 2, or 3, wherein one end of the refrigerant amount adjusting circuit is connected to an upstream side of a low-pressure pipe of the internal heat exchanger. The refrigerator according to any one of claims 1 to 4, wherein the other end of the refrigerant amount adjusting circuit is connected to a downstream side of a high pressure side pipe of the internal heat exchanger. A cooler inlet temperature detecting means for detecting a temperature on an inlet side of the cooler, a cooler outlet temperature detecting means for detecting a temperature on an outlet side of the cooler, and an opening degree of the low pressure side valve and the high pressure side valve. Control device to control,
This control device generates a cooler inlet / outlet temperature difference from the detected value of the cooler inlet temperature detecting means and the detected value of the cooler outlet temperature detecting means, and when the cooler inlet / outlet temperature difference is large, opens the low pressure side valve. When the opening of the high pressure side valve is reduced or closed and the temperature difference between the inlet and outlet of the cooler is small, the opening of the low pressure side valve is reduced or closed and the opening of the high pressure side valve is increased. The refrigerator according to any one of claims 1 to 5, further comprising: In a refrigerator in which the outer shell is formed of an insulated box and the front opening of which is opened and closed by an insulated door,
An air-cooled heat exchanger in which the high-temperature and high-pressure gaseous refrigerant compressed by the compressor is sequentially cooled from the discharge port of the compressor, a high-pressure side pipe of an internal heat exchanger, a pressure reducing device, and a pressure reducing device. A refrigeration cycle that returns to the compressor inlet through a cooler that cools the inside of the refrigerator with low-temperature refrigerant, and a low-pressure pipe that exchanges heat with the high-pressure pipe of the internal heat exchanger;
One end is connected to the low-pressure side refrigerant circuit of the refrigeration cycle, and the other end is connected to the high-pressure side refrigerant circuit, a refrigerant amount adjustment circuit,
A low-pressure side valve provided at one end of the refrigerant amount adjustment circuit,
A refrigerator comprising: a high-pressure side valve provided at the other end of the refrigerant amount adjusting circuit.

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