JP2000249420A - Ice thermal storage device and ice thermal storage refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve unification in ice making and ice thawing and prevent lowering of efficiency of a compressor by reversing a flowing direction of refrigerant between a first direction wherein the refrigerant flows from a first end side to a second end side in a heating tube, and a second direction wherein the refrigerant flows from the second end side to the first end side. SOLUTION: An ice thermal storage device 16 is arranged such that a heating tube 15 in which refrigerant flows is immersed in water 17 for making ice. Further, switching means 33-40 are provided for reversing the flowing direction of the refrigerant in the heating tube 15 between a first direction wherein the flow occurs from a first end side toward a second end side, and a second direction wherein the flow occurs from the second end side toward the first end side. In an ice making operation, when flowing of the refrigerant causes much more attachment of ice on one end portion side of the heating tube 15 than the other end portion side thereof, the direction of the refrigerant flow is switched. As a result, ice is attached more to the side which used to have less attachment of ice, thereby totally unifying attachment of ice. Also, in an ice thawing operation, by switching the refrigerant flow, the inclination of ice thawing an be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice heat storage device and an ice heat storage type refrigeration device in which the ice heat storage device is incorporated in a refrigerant circuit, and more particularly, to ice making water stored in an ice heat storage tank. The present invention relates to a so-called static ice heat storage device having a configuration in which a heat transfer tube is immersed therein, and to a measure for equalizing ice making and defrosting.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to use a static type ice heat storage device in an air conditioning system or the like as disclosed in, for example, JP-A-8-261519. FIG. 6 shows an example of a circuit configuration of an air conditioning system (1) using the ice heat storage device (16). The refrigerant circuit of the air conditioning system (1) includes a compressor (11), an outdoor heat exchanger (heat source side heat exchanger) (13), an outdoor expansion valve (25), an ice heat storage device (16), An indoor expansion valve (19) and an indoor heat exchanger (use-side heat exchanger) (20) are connected so that refrigerant can be circulated by refrigerant piping, and a discharge side of the compressor (11) A four-way switching valve (12) is provided to reverse the direction of circulation of the refrigerant.

In this refrigerant circuit, the liquid pipe comprises a first liquid pipe (23) and a second liquid pipe (24) parallel to each other, and the ice heat storage device (16) is provided in an ice heat storage tank (14). The first end of the heat transfer tube (15) is connected to the first liquid pipe (23), and the second end of the heat transfer tube (15) is
The end side is connected to the second liquid pipe (24). The first liquid pipe (23) is provided with the outdoor expansion valve (25) and the first on-off valve (26), and the second liquid pipe (24) is provided with the second on-off valve (27). A third on-off valve (28) is provided. Furthermore, a bypass passage that bypasses the indoor heat exchanger (20) is provided in the refrigerant circuit.
(31), and a fourth on-off valve is provided in the bypass passage (31).
(32) is provided.

The heat transfer tube (15) of the ice heat storage device (16) is generally composed of a plurality of pipe members (15a) as shown in the figure, and the first liquid pipe (23) is provided with a flow divider (41). And a plurality of capillary tubes (42) connected to the first end of each pipe member (15a). A header (18) is connected to a second end of each pipe member (15a), and the header (18) is connected to a second liquid pipe (24).

[0005] In the air-conditioning system (1), when a cold storage heat operation (ice making operation) is performed, the refrigerant discharged from the compressor (11) is condensed in the condenser (13) as shown by a solid arrow. Thereafter, the pressure is reduced by the expansion valve (25) and supplied to the heat transfer tube (15).
Further, the refrigerant circulates in the refrigerant pipe in a cycle of evaporating in the heat transfer tube (15) and returning to the compressor (11) through the bypass passage (31). Then, when the refrigerant flows through the heat transfer tube (15), it exchanges heat with the water (17) in the ice heat storage tank (14) and evaporates.
By cooling (17), ice is generated around the heat transfer tube (15).

On the other hand, at the time of the cold-heat utilization operation (during the de-icing operation), the open / close state of the outdoor expansion valve (25) and each of the on-off valves (26-28) is switched to discharge the refrigerant discharged from the compressor (11) After being supercooled or condensed by flowing from the opposite direction to the heat transfer tube (15) as indicated by the dashed arrow, the room is cooled using ice cold by passing through the indoor heat exchanger (20). I have to. In this system (1), by performing the above-described operation, the indoor cooling can be performed by using the cold storage heat, so that ice is generated using late-night power, and this cold heat is extracted during the day. Thus, power consumption during the day can be reduced.

In recent years, in view of global environmental problems,
Replacement of refrigerants is being promoted. Various refrigerants have been studied as refrigerants that do not adversely affect the global environment. However, there is hardly any single refrigerant that satisfies predetermined conditions, and the possibility of using a mixed refrigerant is increasing in the future. Among them, most promising mixed refrigerants are non-azeotropic mixed refrigerants.

[0008]

Therefore, a case where a single refrigerant is used and a case where a non-azeotropic mixed refrigerant is used in an ice storage type refrigerating apparatus such as the above-described air conditioning system (1) will be considered. First, in the case of a single refrigerant, the evaporating temperature of the refrigerant gradually decreases due to the pressure loss in the heat transfer tube (15) during the cold storage operation, so that the outlet (second end) side of the heat transfer tube (15) is It was easy for ice to accumulate, and it did not tend to accumulate uniformly around the heat transfer tube (15). In this case, during the operation using the cold heat, the ice is thawed from the second end side where the ice is thick. However, since the ice making itself is not uniform, the thaw may not be stably performed, and the ice may remain unmelted. Problems sometimes occurred.

On the other hand, when a non-azeotropic mixed refrigerant is used,
During cold storage operation, the evaporation temperature of the inlet side of the heat transfer tube (15) decreases due to evaporation from the refrigerant having a low boiling point, and the heat transfer coefficient in the inlet side of the tube is good (dryness is small). Conversely, icing tended to occur on the inlet side of the heat transfer tube (15). On the other hand, a method of increasing the pressure loss in the heat transfer tube (15) by elongating the length of the tube to equalize the evaporation temperature and make the ice making uniform is conceivable.
A new problem arises, such as an increase in the pressure difference in the circuit and a decrease in the efficiency of the compressor (11).

[0010] Further, in the cold-heat utilization operation using the non-azeotropic mixed refrigerant, when the refrigerant flows in a direction opposite to that in the cold storage heat operation, it is possible to thaw the ice from the thin second end, which is hard to make ice during ice making. Thus, there is a problem that the thawing becomes more uneven compared to the case of a single refrigerant.

As described above, there has been a disadvantage that ice making and deicing are difficult to be performed uniformly in the case of using either a single refrigerant or a non-azeotropic mixed refrigerant. The present invention has been made in view of the above problems, and aims to uniformize ice making and defrosting, and reduce the efficiency of the compressor with the uniformity. To prevent a new problem from occurring.

[0012]

SUMMARY OF THE INVENTION According to the present invention, the operation of switching the flow direction of the refrigerant during ice making or ice melting is performed while suppressing the problems such as a decrease in the efficiency of the compressor and the like. It is intended to be uniform.

Specifically, the first solution taken by the present invention is that a heat transfer tube (15) through which a refrigerant flows is provided in an ice heat storage tank (14) for storing water (17) for ice making. It is premised on an ice heat storage device provided to be immersed in water (17). And heat transfer tubes
The flow direction of the refrigerant in (15) is defined as a first direction from the first end to the second end of the heat transfer tube (15) and a second direction from the second end to the first end. Switching means (33 to 40) for reversing are provided.

[0014] A second solution taken by the present invention is:
In the first solution, the switching means (33 to 40) is configured to flow the refrigerant through the heat transfer tube (15) while switching between the first direction and the second direction during the cold storage operation. .

[0015] A third solution taken by the present invention is:
In the first solving means, the switching means (33 to 40) is configured to flow the refrigerant through the heat transfer tube (15) while switching between the first direction and the second direction during the operation using cold heat. .

A fourth solution taken by the present invention is:
In the first solving means, the switching means (33 to 40) is configured to allow the refrigerant to flow through the heat transfer tube (15) while switching between the first direction and the second direction during the cold storage operation and the cold utilization operation. It is composed.

Further, a fifth solution taken by the present invention is:
In any one of the first to fourth solutions, the refrigerant to be used is a non-azeotropic mixed refrigerant.

A sixth solution taken by the present invention is:
The ice heat storage device of any one of the first to fifth solving means is premised on an ice heat storage refrigeration device incorporated in a refrigerant circuit. The refrigerant circuit includes a first liquid pipe (23) and a second liquid pipe (24) provided in parallel between the heat source side heat exchanger (13) and the use side heat exchanger (20). And a bypass passage (31) for the side heat exchanger (20). Also, the first liquid pipe (23)
Has an expansion valve (25) and a first on-off valve (26) located downstream thereof.
Are provided in series, and a second on-off valve (2
7) and a third on-off valve (28) are provided in series, and a bypass passage is provided.
(31) is provided with a fourth on-off valve (32).

Further, in the sixth solution, the switching means (33-40) comprises a first liquid pipe (23) between the expansion valve (25) and the first on-off valve (26) and a heat transfer pipe. (15), a first connecting pipe (33) connected to the first end side, a first liquid pipe (23) between the expansion valve (25) and the first on-off valve (26), and a heat transfer pipe ( The second connecting pipe (34) connected to the second end of the second switching valve (15), the second on-off valve (27) and the third on-off valve (2).
8), a third connecting pipe (35) connected to the second end of the heat transfer pipe (15), a second on-off valve (27) and a third on-off valve ( A fourth connecting pipe (36) connected to the second liquid pipe (24) between the second connecting pipe and the first end of the heat transfer pipe (15);
There are provided first to fourth switching valves (37 to 40) which can be opened and closed, respectively provided in the communication pipes (33 to 36).

Further, a seventh solution taken by the present invention is:
In the sixth solution, the heat transfer tube (15) includes a plurality of pipe members (15a) connected in parallel with each other, and a first header (18) connected to each first end of the pipe members (15a).
a) and a second header (18b) to which each second end of the pipe member (18a) is connected. In addition, the first connecting pipe (3
3) is connected to the first end of each pipe member (15a) via a flow divider (41) and a plurality of capillary tubes (42), and the second connecting pipe (34) is connected to the flow divider (43) And multiple capillary tubes (4
4) is connected to the second end of each pipe member (15a) through
The third connecting pipe (35) is connected to the second header (18b), and the fourth connecting pipe (35) is connected to the fourth connecting pipe (35).
The connecting pipe (36) is connected to the first header (18a).

In the first solution, the refrigerant is circulated during the ice making operation, and when the amount of icing at one end of the heat transfer tube (15) becomes larger than that at the other end, the refrigerant is cooled. Is switched.
Then, this time, more icing will occur on the side with less icing, and icing will be averaged as a whole. Also, at the time of defrosting, by switching the flow direction of the refrigerant, the bias of defrosting is prevented, and more uniform defrosting is performed.

Next, in the second solution, the flow direction of the refrigerant is switched during the ice making operation, and in the third solution, the flow direction of the refrigerant is switched during the ice defrosting operation.
In the fourth solution, the flow direction of the refrigerant is switched during both the ice making operation and the ice melting operation. In the fifth solution, when the non-azeotropic mixed refrigerant is used, the flow is changed. While changing directions, ice making and melting are performed.

In the sixth solution, the first on-off valve (2) is controlled while controlling the opening of the expansion valve (25) during the cold storage operation.
6) is fully closed, and the refrigerant is supplied to the heat transfer tube (15) of the ice heat storage device (16). At this time, when the first and third switching valves (37, 39) are opened and the second and fourth switching valves (38, 40) are closed, the refrigerant flows from the first communication pipe (33) to the heat transfer pipe (15). It flows into the first end side and further flows in the direction (first direction) toward the second end of the heat transfer tube (15),
It flows out of the heat transfer pipe (15) through the third connecting pipe (35). At this time, the second to fourth on-off valves (26 to 28) are connected to the heat transfer tubes (1).
The refrigerant that has passed through 5) passes through the bypass passage (31), and the compressor (1).
The opening / closing state is controlled so as to return to 1).

In this state, if the operation is continued for a predetermined time and the icing is unbalanced, the first and third switching valves (37, 39) are closed and the second and fourth switching valves (37, 39) are closed.
The switching valves (38, 40) are opened, and the second connecting pipe (34) and the fourth connecting pipe (3
Using 6), the refrigerant flows from the second end to the first end (second direction) of the heat transfer tube (15). Then, more icing will occur on the side where there was less icing, and the icing will be uniform. On the other hand, when the open / close state of each of the switching valves (37 to 40) is switched also at the time of defrosting, the operation can be performed while reversing the flow direction of the refrigerant, thereby making the defrosting uniform.

Further, in the above-mentioned seventh solution means, in the regenerative heat operation, regardless of whether the refrigerant flows in the first direction or the second direction, the refrigerant flows in the state of the liquid refrigerant in the flow divider (41, 43) and the capillary tube. (42,44), uniformly flow into each pipe material (15a), and out of each pipe material (15a), merge at the headers (18a, 18b) in the state of gas refrigerant and then bypass
Flow to (31). On the other hand, at the time of operation using cold heat, the refrigerant is
The liquid phase does not change and the header (18a, 18
b) It flows in from the side, is supercooled, and further flows to the use side heat exchanger (20) through the capillary tubes (42, 44) and the like.

On the other hand, for example, in the refrigerating apparatus using the conventional ice heat storage device (16) shown in FIG. 6, the configuration of the capillary tube (42) and the header (18) is kept as it is and the refrigerant piping side When the flow direction of the refrigerant can be switched by, for example, when the flow direction is switched during the cold storage operation, the gas refrigerant flowing out of the heat transfer tube (15) passes through the capillary tube (42), so that the pressure loss However, in the seventh solution, not only the flow direction of the refrigerant can be simply reversed but also the flow dividers are provided at both ends of the heat transfer tube (15). (41,4
3) and capillary tubes (42,44) and headers (18a, 18
b) and the gas refrigerant flows into the capillary tube (42,44)
Such a problem does not occur.

[0027]

According to the first to fourth solutions, ice making and melting can be performed more uniformly, so that ice can be efficiently generated during ice making. In addition, when the ice is thawed, by uniformly melting the ice, it is possible to prevent the unmelted portion of the ice from occurring and to improve the utilization efficiency of the cold heat.

According to the fifth solution, even when a non-azeotropic mixed refrigerant which conventionally tends to make ice making and ice melting more uneven than a single refrigerant is used, uniform ice making and ice melting can be achieved. It is possible to improve the efficiency at the time of ice making and to prevent the unmelted residue at the time of melting ice.

According to the sixth aspect, in the refrigeration system to which the ice heat storage device of the first to fifth aspects is applied, each of the on-off valves (26 to 28) and the like is controlled while controlling the open / close state thereof. The flow direction of the refrigerant can be reversed simply by switching the switching valves (37 to 40), and the effects of the first to fifth solving means can be easily obtained.

According to the seventh solution, the flow divider (41) and the capillary tube (4) are provided in order to prevent the refrigerant from drifting in the heat transfer tube (15) composed of the plurality of pipe members (15a).
2) In a practical configuration of an ice heat storage device, a shunt (43) and a capillary tube (44) are also added to the opposite end of the heat transfer tube (15) so that the refrigerant can be operated during the cold storage operation. Even if the flow direction is switched, it is possible to prevent problems such as pressure loss from occurring.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, a static ice heat storage device (16) is used for an air conditioning system (1) for a building or the like.
This is an example applied to The system (1) is configured as a system using R407C, which is a kind of non-azeotropic refrigerant mixture.

-System Configuration- FIG. 1 is a circuit diagram showing the configuration of the air conditioning system (1). As shown, this air conditioning system (1) has an outdoor unit (2), a heat storage unit (3), and an indoor unit (4).
It is composed of In the figure, the indoor unit (4) is
Although only the table is shown, the indoor unit (4)
It is also possible to connect a plurality of units in parallel.

The outdoor unit (2) includes a compressor (11), a four-way switching valve (12), and an outdoor heat exchanger (heat source side heat exchanger) (13).
Are provided. The four-way switching valve (12) is connected to the first port (1
2a) communicates with the second port (12b) and the third port
(12c) and the state of the solid line communicating with the fourth port (12d);
The first port (12a) and the fourth port (12d) communicate with each other while the second port (12b) and the third port (12c) communicate with each other so as to be switched to the state shown by a broken line.

The heat storage unit (3) is provided with an ice heat storage device (16) including an ice heat storage tank (14) and a heat transfer tube (15).
Water for ice making (or other heat storage medium) (17) is stored in the ice heat storage tank (14), and the heat transfer tube (15) is provided so as to be immersed in the water (17). ing. Specifically, the heat transfer tube (15) has a first end connected to the first header (18a) and a second end connected to the second header (18b), and a plurality of pipe members (15) arranged in parallel. 15a). Each pipe member (15a) has a configuration in which upper ends and lower ends of a plurality of pipes extending in the vertical direction are connected by a U-shaped pipe in the heat storage tank (14) in the drawing, but extends in the horizontal direction. A configuration in which respective ends of a plurality of pipes are connected by a U-shaped pipe may be used. In the figure, for simplicity, the pipe material (15a)
Represents only two lines.

The indoor unit (3) includes an indoor expansion valve.
(19) and an indoor heat exchanger (use-side heat exchanger) (20).

-Circuit Configuration- Next, a specific circuit configuration of the refrigerant circuit in the air conditioning system (1) will be described. First, the discharge side of the compressor (11) is connected to the first four-way switching valve (12) via the discharge gas pipe (21).
Connected to port (12a), the second port of four-way switching valve (12)
(12b) is connected to the outdoor heat exchanger (1) through the first gas pipe (22).
3) is connected to one end.

A liquid pipe between the outdoor heat exchanger (13) and the indoor heat exchanger (20) is a first liquid pipe (23) provided in parallel with each other.
(A dashed-dotted line) and a second liquid pipe (24) (a dashed-dotted line). An expansion valve (electronic expansion valve) (25) and a first opening / closing valve (26) located downstream of the first liquid pipe (23) are provided in series with the first liquid pipe (23). The second on-off valve (27) and the third on-off valve (28) are provided in series. Note that an electromagnetic valve is used for each of the on-off valves (26 to 28).

The indoor heat exchanger (20) is connected to the fourth port (12d) of the four-way switching valve (12) through the second gas pipe (29),
The third port (12c) of the four-way switching valve (12) is connected to the intake gas pipe (3
0) is connected to the suction side of the compressor (11). In this refrigerant circuit, the second liquid pipe (24) and the second gas pipe
(29), a bypass passage (31) for the use-side heat exchanger (20) is provided, and the bypass passage (31) has a fourth on-off valve (3
2) A solenoid valve is provided.

The ice heat storage device (16) is provided with a first liquid pipe (23) and a second liquid pipe (23).
It is connected between the liquid pipes (24). Specifically, heat transfer tubes
The end on the first end side and the end on the second end side of (15) are respectively connected to the first connecting pipe (33) and the second connecting pipe (34) by the first connecting pipe (34).
A second header (18b) and a first header connected to a position between the expansion valve (25) and the first on-off valve (26) of the liquid pipe (23) and provided at both ends of the heat transfer pipe (15). (18a) and the third
The second liquid pipe (2) is connected by the connecting pipe (35) and the fourth connecting pipe (36).
4) It is connected at a position between the two on-off valves (27, 28).

In this embodiment, the first connecting pipe (33) has the first
A switching valve (37), a second switching valve (38) in the second connecting pipe (34),
The third communication pipe (35) is provided with a third switching valve (39), and the fourth communication pipe (36) is provided with a fourth switching valve (40). Solenoid valves are used for these switching valves (37 to 40). And
The connecting pipes (33 to 36) and the switching valves (37 to 40) constitute switching means for controlling the flow direction of the refrigerant.

The first connecting pipe (33) is made of a pipe material (15a).
The pipes (15a) are connected to the first end of each pipe member (15a) via a flow divider (41) and a plurality of capillary tubes (42) corresponding to the number of the pipe members (41). The pipes (15a) are connected to the second ends of the pipe members (15a) via flow dividers (43) and a plurality of capillary tubes (44) corresponding to the number of pipes (15a).

-Operation- Next, the operation of the air conditioning system (1) will be described. This air conditioning system (1) uses a cold storage heat operation (ice making operation) that generates ice as a cold heat source in the ice heat storage tank (14), and uses the cold heat of the ice generated in the ice heat storage tank (14). Operation in four modes: cooling operation using cold energy to cool the room (de-icing operation), non-use cooling operation to cool the room without using the heat of ice, and heating operation in which the circulation direction of the refrigerant is reversed. It can be performed.

<Cooling Energy Operation Mode> First, the cooling energy operation mode will be described with reference to FIG. In this mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor (11)
It is condensed and liquefied in the outdoor heat exchanger (13). During the cold storage operation, the first on-off valve (26) and the second on-off valve (27) are closed, and the third on-off valve (28) and the fourth on-off valve (32) are open. Therefore, the liquid refrigerant that has passed through the outdoor heat exchanger (13) is decompressed through the outdoor expansion valve (25), and then depressurized.
It flows into the heat transfer tube (15) of (16).

At first, the first and third switching valves (37, 39) are opened and the second and fourth switching valves (3 to 40) are opened.
8,40) is closed. Therefore, the liquid refrigerant passes through the flow divider (41) and the capillary tube (42) from the first switching valve (37) and passes through the heat transfer tube (15) from the first end side, as indicated by the solid arrow. It flows in the direction toward the second end (first direction). At this time, heat exchange is performed between the liquid refrigerant and the ice making water (17), and the refrigerant evaporates to a gas, and ice is generated around the heat transfer tube (15). The gas refrigerant that has exited the heat transfer tube (15) merges at the second header (18b), and further passes through the third switching valve (39), the third on-off valve (28), and the fourth on-off valve (32). 2 gas piping
(29), and returns to the compressor (11) via the four-way switching valve (12).

The non-azeotropic mixed refrigerant has a characteristic that the temperature changes when it is evaporated or condensed in the heat transfer tube (15) because of its non-azeotropic property. The entrance side is lower than the exit side. Therefore, when the refrigerant is circulated in the flow shown by the solid arrow in FIG.
In addition to the good heat transfer coefficient inside the tube (end side), the heat transfer tube (1
The ice generated at the first end in 5) is thicker than the ice generated at the second end. Therefore, at a predetermined timing, the first and third on-off valves (37, 39) are closed, and the second and fourth on-off valves (38, 39) are closed.
40) Perform a switching operation to open. Then, the refrigerant is
The direction of the heat transfer tube (15) is changed from the second end side to the first end side (second direction) by changing the direction as shown by the broken line arrow. Ice formation is faster at the edge.

In this way, the heat transfer tube (1
By switching the flow direction of the refrigerant in 5) or repeating the switching several times as necessary, the heat transfer tube
Ice is uniformly generated around (15).

<Cooling Cooling Operation Mode> Next, the flow of the refrigerant will be described in the cooling cooling operation mode shown in FIG. In this mode, the four-way switching valve (12) is in the same state as the cold storage operation of FIG. 2, but the outdoor expansion valve (25), the third on-off valve (28) and the fourth on-off valve (32) are all It is controlled to be closed, and the first on-off valve (26) and the second on-off valve (27) are opened. Therefore, the refrigerant discharged from the compressor (11) is condensed in the outdoor heat exchanger (13) as shown by the solid arrow, and
It flows into the heat transfer tube (15) through (24).

At this time, initially, the first and third switching valves (37,
39) is opened, and the second and fourth switching valves (38, 40) are closed. For this reason, the refrigerant flows from the third switching valve (39) through the second header (18b) through the heat transfer tube (15) in the second direction, is supercooled, and is further cooled by the capillary tube (42) and the flow divider (41). ), Flows into the indoor expansion valve (19) and the indoor heat exchanger (20) through the first switching valve (37) and the first on-off valve (26). The refrigerant exchanges heat with the indoor air in the indoor heat exchanger (20) to evaporate, cools the indoor air, and returns to the compressor (11).

In this case, the temperature of the refrigerant is higher at the inlet (second end) side of the heat transfer tube (15) than at the outlet (first end) side. Therefore, when this operation is continued, the ice around the heat transfer tube (15) melts from the second end side, which is the inflow side of the refrigerant,
The first end side, which is the outlet side, tends to remain undissolved.
Therefore, in this case also, at a predetermined timing, a switching operation of closing the first and third switching valves (37, 39) and opening the second and fourth switching valves (38, 40) is performed. Then, the refrigerant flows through the heat transfer tube (15) in the first direction, as indicated by the broken arrow,
The ice on the first end will melt.

Also in this case, at least once the heat transfer tube (15)
By switching the flow direction of the refrigerant in the above, or by repeating the switching several times as necessary, it is possible to uniformly melt the ice around the heat transfer tube (15) and prevent generation of unmelted residue.

<Non-Use Cooling Operation Mode> Next, the flow of the refrigerant in the non-use cooling operation mode shown in FIG. 4 will be described. In this operation mode, indoor cooling is performed without using the ice heat storage device (16). At this time, the four-way switching valve (12) is in the same state as in FIGS. 2 and 3, but the outdoor expansion valve (25), the first on-off valve (26) and the fourth on-off valve (32) are fully closed. Controlled by
The second on-off valve (27) and the third on-off valve (28) are open.

Therefore, the refrigerant discharged from the compressor (11) flows into the outdoor heat exchanger (13) through the four-way switching valve (12), and is condensed in the heat exchanger (13). It flows into the indoor expansion valve (19) through the second on-off valve (27) and the third on-off valve (28). The refrigerant is decompressed by the indoor expansion valve (19), flows into the indoor heat exchanger (20), exchanges heat with the indoor air to cool the indoor air, and evaporates itself to become a gas, which is compressed. Machine (11)
Return to In this mode, the room is cooled by repeating the above cycle.

<Heating operation mode> Next, the flow of the refrigerant will be described in the heating operation mode shown in FIG. In this operation mode, the four-way switching valve (12) is switched from the state shown by the solid line to the state shown by the broken line in FIG. Further, the indoor expansion valve (19) is controlled to be fully opened, and the outdoor expansion valve (25) is controlled to be open. Further, the first on-off valve (26) is controlled to be fully opened, and the second on-off valve (2
7), the third on-off valve (28), and the fourth on-off valve (32) are controlled to be fully closed.

In this state, the refrigerant discharged from the compressor (11) flows into the indoor heat exchanger (20) through the second gas pipe (29), where the refrigerant is discharged from the indoor heat exchanger (20). Heats room air when condensing by exchanging heat with air. After passing through the indoor expansion valve (19) and the first on-off valve (26), the outdoor expansion valve (2
After the pressure is reduced in 5), it is evaporated in the outdoor heat exchanger (13) and returns to the compressor. In this mode, the room is heated by repeating the above cycle.

-Effects of Embodiment- According to this embodiment, the refrigerant is transferred to the heat transfer tube (15) during the cold storage operation.
When the icing on one end side of the heat transfer tube (15) is larger than that on the other end side, the flow direction of the refrigerant is switched to the other end of the heat transfer tube (15). Since the amount of icing on the side of the end is increased, the icing can be made uniform as a whole and the efficiency can be increased. Also, when the ice is thawed, the direction of flow of the refrigerant is switched so that the ice is more evenly thawed.

Further, the flow direction of the refrigerant is changed by each switching valve (37, 3).
8,39,40), the switching operation can be easily performed.

Further, the first liquid pipe (23) is connected to the flow dividers (41, 43) and the capillary tubes (42, 44) at both the first end and the second end of the heat transfer tube (15). The first connecting pipe (33) and the second
Connected by the communication pipe (34), the second liquid pipe (24) was connected to the fourth communication pipe (3
6) and the third connecting pipe (35) are connected to the first header (18a) and the second header (18b).
Can be switched by the ice heat storage device (16) composed of a plurality of pipe materials (15a), and when performing the cold storage heat operation, the gas refrigerant passes through the capillary tubes (42, 44) and the compressor. There is an advantage that the efficiency does not decrease due to pressure loss without returning to (11).

[0058]

Other Embodiments of the Invention The present invention may be configured as follows with respect to the above embodiment.

For example, in the above embodiment, the ice heat storage device (16) of the present invention is applied to an air conditioning system (1) using a non-azeotropic mixed refrigerant.
However, a single refrigerant can be used instead of the non-azeotropic refrigerant mixture. In the case of using a single refrigerant, conventionally, there was a problem that the outlet side of the heat transfer tube (15) was more likely to icing than the inlet side, but by applying the configuration of the present embodiment, the icing was made uniform, and Thawing can be uniformed. In particular, when a single refrigerant is used, the length of the heat transfer tube (15) is long, and the pressure loss inside the heat transfer tube (15) is large (that is, the temperature difference of the refrigerant between the inlet side and the outlet side of the heat transfer tube is large). The present invention is effective.

The refrigerant circuit of the above embodiment is merely an example and can be changed as appropriate. In short, the flow direction of the refrigerant in the ice heat storage device (16) during the ice making operation or the ice melting operation is changed. It is only necessary to be able to switch, and for example, the present invention can be applied not only to the peak shift type described above but also to a peak cut type system. Further, the present invention is applicable to refrigeration devices other than the air conditioning system (1).

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an air conditioning system using an ice heat storage device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a cold storage operation mode of the air conditioning system of FIG. 1;

FIG. 3 is a diagram showing a cooling operation using cooling energy of the air conditioning system of FIG. 1;

FIG. 4 is a diagram showing a non-use cooling operation mode of the air conditioning system of FIG. 1;

FIG. 5 is a diagram showing a heating operation mode of the air conditioning system of FIG. 1;

FIG. 6 is a circuit configuration diagram of an air conditioning system using a conventional ice heat storage device.

[Explanation of symbols]

 (1) Air conditioning system (ice storage type refrigeration system) (2) Outdoor unit (3) Heat storage unit (4) Indoor unit (11) Compressor (12) Four-way switching valve (13) Outdoor heat exchanger (heat source side heat) (14) Ice storage tank (15) Heat transfer tube (15a) Pipe material (16) Ice storage device (17) Water (18a) First header (18b) Second header (19) Indoor expansion valve (20) Indoor heat exchanger (use side heat exchanger) (23) First liquid pipe (24) Second liquid pipe (25) Expansion valve (26) First open / close valve (27) Second open / close valve (28) Third open / close Valve (31) Bypass passage (32) Fourth on-off valve (33) First communication pipe (switching means) (34) Second communication pipe (switching means) (35) Third communication pipe (switching means) (36) No. 4 communication pipe (switching means) (37) 1st switching valve (switching means) (38) 2nd switching valve (switching means) (39) 3rd switching valve (switching means) (40) 4th switching valve (switching means) (41) Flow divider (42) Capillary tube (43) Flow divider (44) Capillary tube

Claims (7)

[Claims] An ice thermal storage tank (14) for storing water (17) for ice making.
Inside, a heat transfer tube (15) through which a refrigerant flows is an ice heat storage device provided so as to be immersed in the water (17), and transfers a flow direction of the refrigerant in the heat transfer tube (15). Switching means (33) for reversing a first direction from the first end side to the second end side of the heat tube (15) and a second direction from the second end side to the first end side.
~ 40) ice heat storage device. 2. The switching means (33 to 40) is adapted to operate during cold storage operation.
While switching the refrigerant between the first direction and the second direction, the heat transfer tubes (1
The ice heat storage device according to claim 1, wherein the ice heat storage device is configured to be circulated in (5). 3. The switching means (33 to 40) is configured to flow the refrigerant through the heat transfer tube (15) while switching between the first direction and the second direction during the operation using cold heat. Ice thermal storage device. 4. The switching means (33-40) is configured to flow the refrigerant through the heat transfer tube (15) while switching between the first direction and the second direction during the cold storage operation and the cold utilization operation. The ice heat storage device according to claim 1. 5. The refrigerant according to claim 1, wherein the refrigerant is a non-azeotropic mixed refrigerant.
An ice heat storage device according to any one of claims 1 to 4. 6. An ice storage type refrigeration system in which the ice heat storage device (16) according to claim 1 is incorporated in a refrigerant circuit.
(1) wherein the refrigerant circuit comprises a heat source side heat exchanger (13) and a use side heat exchanger.
A first liquid pipe (23) and a second liquid pipe (24) provided in parallel with each other between (20), and a bypass passage of the use side heat exchanger (20);
(31), and an expansion valve (25) is provided in the first liquid pipe (23).
And a first on-off valve (26) located downstream thereof is provided in series, and a second on-off valve (27) and a third on-off valve are provided in the second liquid pipe (24).
(28) are provided in series, a fourth opening / closing valve (32) is provided in the bypass passage (31), and the switching means (33-40) is provided with the expansion valve (25) and the first opening / closing valve (26). )
, A first connecting pipe (33) connected to the first end of the heat transfer pipe (15), an expansion valve (25) and a first on-off valve (2).
A second connecting pipe (34) connected to the first liquid pipe (23) and the second end of the heat transfer pipe (15), a second on-off valve (27) and a third on-off valve (28), a third connecting pipe (35) connected to the second end of the heat transfer pipe (15), a second on-off valve (27), and a third on-off valve. A fourth connecting pipe (36) connected to the second liquid pipe (24) between the second connecting pipe (28) and the first end of the heat transfer pipe (15); 36. An ice storage type refrigerating apparatus comprising a first to fourth switching valves (37 to 40) which can be opened and closed respectively provided in 36). 7. A heat transfer tube (15) comprising a plurality of pipe members (15a) connected in parallel to each other, a first header (18a) connected to each first end of said pipe members (15a), The pipe material (15a)
A second header (18b) to which each second end of the pipe member (18b) is connected. The first connecting pipe (33) is connected to each pipe member (15a) via a flow divider (41) and a plurality of capillary tubes (42). The second communication pipe (34) is connected to the second end side of each pipe member (15a) via a flow divider (43) and a plurality of capillary tubes (44). 7. The ice regenerative refrigerator according to claim 6, wherein the third connecting pipe (35) is connected to the second header (18b), and the fourth connecting pipe (36) is connected to the first header (18a).