JP3000584B2 - Refrigeration equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigeration apparatus.

(Prior Art) For example, Japanese Patent Application Laid-Open No. Sho 62-266361 discloses that one indoor unit having a compressor and an outdoor heat exchanger is connected to a plurality of indoor units each having an indoor heat exchanger. Is described. In the device, the defrosting operation for removing the frost adhered and grown on the outdoor heat exchanger during the heating operation is performed by a so-called forward cycle defrost method in which the refrigerant discharged from the compressor is directly supplied to the outdoor heat exchanger. Has been made. In such a defrosting operation cycle, the liquid refrigerant radiated and condensed by the outdoor heat exchanger is separated from gas components in an accumulator provided in a suction pipe of the compressor and stored in the accumulator. .

On the other hand, in the multi-type air conditioner as described above,
For example, there is a large difference in the required amount of circulating refrigerant between the case where the heating operation is performed simultaneously in all the rooms and the case where only one room is performed. Therefore, the required amount of circulating refrigerant is normally filled in the piping path during all-room operation, and a liquid receiver is provided in the liquid-side piping connecting the outdoor heat exchanger and each indoor heat exchanger. ,
At the time of the operation that generates a surplus, the surplus refrigerant is stored in the liquid receiver, and the operation is performed with the circulating refrigerant amount according to the number of operating rooms on the indoor side.

(Problems to be Solved by the Invention) By the way, at the time of steady operation of heating and cooling, relatively little liquid refrigerant is separated from the circulating refrigerant by the accumulator, and the most liquid refrigerant during the defrosting operation by the above-described normal cycle defrost. Refrigerant is separated in the accumulator. Therefore, a large-sized accumulator having a storage capacity equivalent to the total filling amount is provided in accordance with the amount of the separated liquid refrigerant at this time. On the other hand, in order to store a large amount of excess refrigerant generated when only one chamber is operated, the above-mentioned liquid receiver needs to have an internal capacity close to the total filling amount. As a result, these accumulators and receivers are required. When the two reservoirs of the liquid container are disposed in the outdoor unit, a large exclusive space is required for each, and there is a problem that the size of the apparatus cannot be sufficiently reduced.

The present invention has been made in view of the above, and an object of the present invention is to provide a refrigeration apparatus which enables a reduction in the storage capacity of the liquid storage container as described above, thereby making the apparatus compact. .

(Means for Solving the Problems) Therefore, in the refrigerating apparatus of the present invention, the discharge-side gas pipe 2, the condenser 15, the liquid-side pipes 10, 13, the evaporator 8, and the suction-side gas pipe 3 are sequentially connected to the compressor 1. To form a refrigerant circuit,
An accumulator section 18 is provided on the suction side gas pipe 3, and a first flow control valve 9, a liquid receiving section 19, and a second flow control valve 12 are sequentially provided on the liquid side pipes 10 and 13 from the evaporator 8 side. Further, a refrigerating apparatus in which the evaporator 8 side of the liquid side pipe 10 with respect to the first flow control valve 9 is connected to the discharge side gas pipe 2 by a bypass pipe 22 provided with a defrost opening / closing valve 21. And the accumulator section 18 and the liquid receiving section.
And the liquid refrigerant in the accumulator section 18 when the opening / closing means 39 is opened, and the liquid refrigerant in the accumulator section 18 passes through the communication flow path when the opening / closing means 39 is opened.
During the defrosting operation in which the defrost opening / closing valve 21 is opened and the refrigerant discharged from the compressor 1 is returned to the compressor 1 from the bypass pipe 22 through the evaporator 8. A defrosting operation control means 40 for closing the first and second flow control valves 9 and 12 and opening the opening / closing means 39 is provided.

(Operation) In the refrigerating apparatus having the above configuration, the liquid receiving section 19 is in communication with only the accumulator section 18 during the defrosting operation of the evaporator 8, and therefore, in this state, the liquid receiving section 19 is separated by the accumulator section 18. It functions as a storage part for the liquid refrigerant to be discharged. That is, the liquid refrigerant separated in the accumulator unit 18 is also moved and stored in the liquid receiving unit 19 together with the accumulator unit 18, so that the accumulator unit 18 and the liquid receiving unit 19 Can be configured to be a storage capacity commensurate with the amount of liquid refrigerant separated by the accumulator unit 18 during the defrosting operation.

(Example) Next, regarding a specific example of the refrigeration apparatus of the present invention,
This will be described in detail with reference to the drawings.

FIG. 1 shows a refrigerant circuit diagram of a multi-type air conditioner constructed by applying the present invention.
Is an outdoor unit. The outdoor unit X includes a compressor 1 therein, and a discharge pipe 2 and a suction pipe 3 of the compressor 1 are connected to a four-way switching valve 4, respectively. The compressor 1 has an inverter 5 for controlling the rotation speed, that is, the compression capacity. Four-way switching valve 4
The first gas pipe 6 and the outdoor fan 7
An outdoor heat exchanger 8 provided with a first electric expansion valve (first flow control valve) 9 and a liquid pipe 10 interposed therebetween are sequentially connected. The other switching port of the four-way switching valve 4 is connected to the other switching port. Second gas pipe 11
Is connected. The distal ends of the liquid pipes 10 are respectively connected to three liquid branch pipes 13 provided with second electric expansion valves (second flow control valves) 12. The distal ends of the second gas pipes 11 are connected to three liquid branch pipes 13. An indoor heat exchanger (B) is provided which is branched into three gas branch pipes 14, 14, respectively, and is provided between the liquid branch pipes 13, 13 and the gas branch pipes 14, respectively. Only the indoor unit A is shown) 15 ・ 15
They are connected in parallel by 16. Each of the indoor heat exchangers 15 is provided with an indoor fan 17. In the above description, the apparatus is configured to be capable of switching between cooling and heating by interposing the four-way switching valve 4. However, during the heating operation described later, each indoor heat exchanger 15 functions as a condenser and the outdoor heat exchanger 8 functions as an evaporator. The discharge pipe 2 and the second gas pipe 11 constitute a discharge-side gas pipe, and the suction pipe 3 and the first
The gas pipe 6 forms a suction-side gas pipe. Also the above liquid tube
The liquid side pipe is constituted by 10 and each liquid branch pipe 13.

Further, the above-mentioned suction side gas pipe, in the above case, the suction pipe 3
The accumulator section 18 of the reservoir unit R described later
A liquid receiving portion 19 of the liquid storage unit R is provided on the liquid side pipe, that is, on the liquid pipe 10 in the liquid pipe 10 on the liquid branch pipe 13 side with respect to the first electric expansion valve 9. I have. In addition, the outdoor heat exchanger 8 is located more than the first electric expansion valve 9 in the liquid pipe 10.
The side pipe portion is connected to the discharge pipe 2 by a bypass pipe 22 provided with a defrost opening / closing valve 21.
The bypass pipe 22 may be connected to the second gas pipe 11 instead of the discharge pipe 2.

FIG. 2 is a schematic view of the configuration of the liquid reservoir unit R in the first embodiment. As shown in the figure, the liquid storage unit R is configured such that an internal space of a substantially cylindrical closed casing 31 is vertically divided by a partition plate 32, and the upper side is an accumulator section 18 and the bottom side is a liquid receiving section 19, respectively. Make up. As described above, the accumulator section 18 interposed in the suction pipe 3 includes an outlet pipe 33 to which a pipe on the compressor 1 side in the suction pipe 3 is connected, and a four-way switching valve 4 in the suction pipe 3. And an inlet side pipe 34 to which the side pipe is connected. The outlet pipe 33 and the inlet pipe 34 have respective open ends at positions separated from each other on the upper side inside the accumulator 19 through the upper end of the casing 31. Also, the above outlet side piping
Reference numeral 33 denotes a U-shaped tube having a U-shaped portion at a position close to the partition plate 32, and a suction hole 35 at the lowest position.
Are drilled. When the refrigerant is circulated by operating the compressor 1, the accumulator section 19 passes through the inlet-side pipe 34.
When the gas-liquid mixed refrigerant flows into the accumulator 19, the liquid component falls to the partition plate 32 side in the accumulator section 19 to cause gas-liquid separation, and the gas refrigerant on the upper side flows into the open end of the outlet pipe 33. From the compressor 1 through the outlet side pipe 33. At the same time, the liquid refrigerant accumulated on the partition plate 32 is discharged by the suction holes 35.
The gas is sucked into the compressor 1 little by little through the compressor and gasified by the compression work in the compressor 1.

On the other hand, a liquid receiving portion 19 provided in the liquid pipe 10 is provided with first and second connection pipes 36 and 37 connected to the liquid pipe 10, respectively, and these first and second connection pipes are provided. The reference numerals 36 and 37 pass through the bottom side of the casing 31 and open into the liquid receiving portion 19, respectively. In the liquid receiving portion 19, the surplus refrigerant amount in the refrigerant pipe is stored. For example, there is a large difference in the required amount of circulating refrigerant between the case where the heating operation is performed in all three rooms and the case where only one room is performed. Usually, the required amount of the circulating refrigerant is filled in the pipe path during the operation of all the rooms. Then one room or two
The surplus refrigerant amount generated during the room operation is stored in the liquid receiving unit 19, and the operation is performed with the circulating refrigerant amount according to the number of operating rooms on the indoor side.

The casing 31 of the liquid reservoir unit R is externally connected to a communication pipe 38 for connecting the bottom side of the accumulator section 18 to the liquid receiving section 19. The communication pipe 38 has an electromagnetic on-off valve (opening / closing means). ) 39 are interposed. When the on-off valve 39 is opened, the accumulator 18
The liquid refrigerant stored therein moves toward the liquid receiving portion 19 by its own weight through the communication pipe 38.

In the air conditioner having the above configuration, the on-off valve 39 of the reservoir unit R is closed, and the four-way switching valve 4 is located at the switching position indicated by the broken line in FIG. The cooling operation is performed by circulating the heat from the outdoor heat exchanger 8 to each of the indoor heat exchangers 15 and 15, and allowing the outdoor heat exchanger 8 to function as a condenser and each of the indoor heat exchangers 15 and 15 to function as an evaporator. Hereinafter, for convenience, control of each operation of the heating operation and the defrosting operation will be described.

For this purpose, as shown in FIG. 1, an operation control device 40 also serving as a defrosting operation control means is provided in the outdoor unit X. When a heating operation request signal is input from an indoor control device (not shown) provided in each of the machines A to C, the defrost opening / closing valve 21 and the opening / closing valve 39 of the liquid storage unit R are both closed to switch four-way. The heating operation is started by starting the compressor 1 with the valve 4 positioned at the switching position indicated by the solid line in the figure. In this heating operation, the refrigerant discharged from the compressor 1 is
The indoor heat exchangers 15 and 15 are supplied from the discharge pipe 2, the four-way switching valve 4 and the second gas pipe 11 to the indoor heat exchangers 15 and 15, respectively.
Condensate at 15. Next, the outdoor heat exchanger 8 is connected via the liquid pipe 10.
After being evaporated in the outdoor heat exchanger 8, the refrigerant is returned to the compressor 1 through the first gas pipe 6, the four-way switching valve 4, and the suction pipe 3. In this case, the superheat degree control of the evaporated refrigerant is performed by the first electric expansion valve 9, and the second electric expansion valves 12 and 12 are controlled.
Thus, by controlling the condensed refrigerant temperatures at the outlets of the indoor heat exchangers 15 and 15 to be the same as each other, the amount of refrigerant distribution to the indoor heat exchangers 15 and 15 is controlled. The second electric expansion valve 12 corresponding to the heating stop room is set to a stop opening degree (an opening degree capable of flowing a small amount of refrigerant corresponding to natural heat radiation in order to prevent liquid return to the compressor 1). You.

During this heating operation, the opening / closing valve 39 of the reservoir unit R is maintained in the closed state, so that the accumulator section
The liquid refrigerant 18 separated from the refrigerant returning to the compressor 1 is stored in the accumulator 18, and the refrigerant circulation path is stored in the liquid receiver 19. The excess refrigerant in the tank is stored.

When the above-described heating operation is continued and frost is generated in the outdoor heat exchanger 8 and the amount of frost increases, the operation control device 40 switches to the defrosting operation. In this defrosting operation, the defrost on-off valve 21 is opened from the above, the on-off valve 39 of the liquid reservoir unit R is further opened, and the first and second electric expansion valves 9 and 12 are closed. As a result, the refrigerant discharged from the compressor 1 flows from the discharge pipe 2 to the bypass pipe 22 and the liquid pipe 10.
Is supplied directly to the outdoor heat exchanger 8 through the
The gas is returned to the compressor 1 via the gas pipe 6, the four-way switching valve 4, and the suction pipe 3. In this circulation cycle, the retained heat of the gas refrigerant discharged from the compressor 1 is given to the outdoor heat exchanger 8,
Defrosting is performed.

In the refrigerant circulation cycle during this defrosting operation, the liquid refrigerant that has radiated heat in the outdoor heat exchanger 8 and condensed is accumulated in the accumulator 18.
And thus a large amount of separated liquid refrigerant is generated in the accumulator section 18. The separated liquid refrigerant moves from the accumulator section 18 to the liquid receiving section 19 and is stored. That is, by closing the first and second electric expansion valves 9 and 12 and opening the on-off valve 39, the liquid receiving section 19 is in a state of communicating only with the accumulator section 18, and therefore, in this state, the liquid receiving section 19 is in communication with the accumulator section 18. The unit 19 functions integrally as a storage unit for the liquid refrigerant separated by the accumulator unit 18. As a result, the accumulator section 18 and the liquid receiving section
It is possible to continue the above defrosting operation with a configuration in which the total content of the liquid storage unit R and the liquid storage unit R is equal to the volume of the separated liquid during the defrosting operation. It can be made smaller in size than the exclusive space required by the and the accumulator.

When the above defrosting operation is completed, the defrost on-off valve 21
Is closed, the on-off valve 39 of the liquid reservoir unit R is closed, and the opening control of the first and second electric expansion valves 9 and 12 during the heating operation is performed, thereby restarting the heating operation. You.
At this time, the liquid refrigerant accumulated in the liquid receiving section 19 is appropriately added to the circulation path, and the operation with the refrigerant circulation amount according to the heating load on the indoor side is started from the beginning of the restart. Conventionally, the liquid refrigerant separated into the accumulator during the defrosting operation is only sucked into the compressor little by little after the heating operation is restarted, and thus the operation is started with the circulating refrigerant amount being insufficient and sufficient heating capacity is obtained. In some cases, a sufficient heating capacity can be provided immediately after the restart of the heating operation.

In the above-described apparatus, the on-off valve 39 of the liquid reservoir unit R is further opened when the operation is stopped, and at the start of the operation, the four-way switching valve 4 is located at the switching position indicated by the broken line in FIG. While maintaining the open state of the valve 39, the first and second electric expansion valves 9 and 12 are both closed and the compressor 1 is started, and the start-up operation is continued for a predetermined short time. At the same time as closing the valve 39, the four-way switching valve 4 is switched to the position indicated by the solid line in the figure, and the opening control during the heating operation is performed on the first and second electric expansion valves 9 and 12 to achieve the steady operation. The shift control is performed by the operation control device 40.

According to the above control, first, when the operation is stopped, the accumulator section 18 of the liquid reservoir unit R is held in a state of communicating with the liquid receiving section 19 through the communication pipe 38. As a result, the liquid refrigerant accumulated in the accumulator section 18 during the previous operation moves toward the liquid receiving section 19 by its own weight through the communication pipe 38. Further, during the above-mentioned start-up operation, the second gas pipe 11, each indoor heat exchanger 15, and each liquid branch pipe 13 are connected through the suction pipe 3.
The suction force of the compressor 1 acts on the pipe paths leading to each of the second electric expansion valves 12 in the closed state, and the liquid refrigerant accumulated in these pipe paths is collected by the accumulator section 18 and The recovered liquid refrigerant moves into the liquid receiving section 19 in the same manner as described above. Therefore, in the state in which the liquid refrigerant accumulated in the accumulator section 18 and the pipe path during the previous operation is collected in the liquid receiving section 19, the operation is shifted to the steady operation. Therefore, in the same manner as when the heating operation is resumed after the above-described defrosting operation, the amount of the circulating refrigerant corresponding to the heating load on the indoor side is secured, and the operation with improved heating capacity is started.
Note that the operation of recovering the liquid in the liquid receiving section 19 at the time of this activation
By performing at the start of the cooling operation, it is possible to start an operation with improved cooling capacity in the same manner as described above, and further, circulate the refrigerant discharged from the compressor from the outdoor heat exchanger to the indoor heat exchanger. In an apparatus configured by adopting a so-called reverse cycle defrost system in which defrosting is performed by switching to a cycle, the liquid collecting operation to the liquid receiving portion 19 is performed at each time of switching between heating and defrosting, thereby removing the liquid. Operation with improved frost capacity and heating capacity can be performed.

FIG. 3 is a schematic view showing the configuration of a second embodiment of the liquid reservoir unit R. In this embodiment, a check valve 41 is provided in the communication pipe 38 as opening / closing means instead of the opening / closing valve 39 in the liquid reservoir unit R of the first embodiment. The check valve 41 is configured to close when the pressure on the liquid receiving section 19 side is higher than that on the accumulator section 18 side, and to maintain the valve open state when the pressure is the same.

The operating condition of the air conditioner in which the liquid reservoir unit R of the second embodiment is incorporated in the refrigerant pipe path of FIG. 1 will be described. The operation is stopped, that is, a high and low pressure difference occurs in the refrigerant pipe path. When there is no compressor, and during the operation of the compressor 1 with the first and second electric expansion valves 9 and 12 closed, the accumulator section 18 and the liquid receiving section 19 are maintained at the same pressure. The check valve 41 is held in the open state. When the first and second electric expansion valves 9 and 12 are opened and the operation is switched to, for example, a refrigerant cycle at the time of heating, the liquid receiving section
The high-pressure side pressure is introduced into 19, the check valve 41 is automatically closed, and the communication between the accumulator section 18 and the liquid receiving section 19 is cut off. Therefore, in the liquid reservoir unit R of the first embodiment, in order to control the operation of the on-off valve 39, an electric circuit component such as a drive relay and a control circuit are further required. Reservoir unit R
, The compressor 1 and the first and second electric expansion valves 9 and 12
Depending on the operating state of the check valve 41, the communication state between the accumulator unit 18 and the liquid receiving unit 19 is automatically switched by the check valve 41, at the time of the operation stop, at the time of the start operation, at the time of the defrosting operation. The liquid collection in the liquid receiving section 19 can be performed with a simpler configuration.

In FIG. 4, in addition to the configuration of the liquid storage unit R of the second embodiment, the accumulator section 18 and the liquid receiving section 19 are connected to each other by a pressure equalizing pipe 43 having a capillary tube 42 interposed therebetween. FIG. 9 is a schematic diagram illustrating a configuration of a liquid storage unit R according to a third embodiment. In the air conditioner incorporating the liquid reservoir unit R of the third embodiment, when the operation is shifted from the steady operation state in which the liquid receiving section 19 and the accumulator section 18 have a high-low pressure difference state to the stop of the operation, The pressure equalization between the accumulator section 18 and the liquid receiving section 19 occurs through the pressure equalizing pipe 43, and the pressure inside both the sections 18 and 19 quickly changes to the same pressure state. The stop valve 41 is opened, whereby the liquid refrigerant accumulated in the accumulator 18 is quickly moved to the liquid receiving portion 19 side. In addition, the pressure equalization of the entire refrigerant pipe path after the operation is stopped is also quickly performed through the pressure equalizing pipe.

FIG. 5 is a schematic view showing the structure of a liquid storage unit R according to a fourth embodiment. In the liquid storage unit R, the partition plate 32 is provided with a through-hole 44 for communicating the accumulator section 18 with the liquid receiving section 19, and at a position on the liquid receiving section 19 side facing the through hole 44, An opening / closing valve 45 containing a shape memory alloy is provided as opening / closing means. The shape memory alloy, which expands and contracts in response to a change in temperature, takes an expanded form on the high temperature side of, for example, 20 ° C. or higher, and at this time, the internal valve body of the on-off valve 45 contacts the partition plate 32 and the penetration On the other hand, at the low temperature side of less than 20 ° C., the shape memory alloy changes to a reduced form at the low temperature side below 20 ° C. At this time, the internal valve body is separated from the partition plate 32 and received by the accumulator section 18 through the through hole 44. The liquid section 19 is in communication with the liquid section 19.

In the air conditioner incorporating the liquid reservoir unit R of the fourth embodiment, the first and second electric expansion valves 9 and 12 are opened to circulate the refrigerant discharged from the compressor 1 through the liquid pipe 10. During normal operation, a high-temperature condensed refrigerant is introduced into the liquid receiving portion 19, and the on-off valve 45 is kept in a closed state to close the through hole 44. At other times, the accumulator portion 18 is passed through the through hole 44. And the liquid receiving section 19 is automatically changed to a communication state. Therefore, also in this case, the liquid recovery to the liquid receiving portion 19 at the time of the operation stop, the start-up operation, and the defrosting operation described above is controlled by switching the communication state between the accumulator portion 18 and the liquid receiving portion 19. This can be performed without separately providing circuit components and the like, and the configuration can be simplified.

Note that, in the above description, the air conditioner for both cooling and heating has been described as an example.However, for example, an air conditioner dedicated to heating and other refrigeration devices can be configured by applying the present invention. In the above description, the configuration in which the accumulator unit 18 and the liquid receiving unit 19 are provided in the same casing 31 has been described as an example, but the configuration in which the accumulator unit and the liquid receiving unit are configured separately and the two are interconnected. And so on.

(Effect of the Invention) As described above, in the refrigeration apparatus of the present invention, the liquid receiving part functions as a storage part for the liquid refrigerant separated by the accumulator part during the defrosting operation. It can be configured to be substantially equal to the amount of the separated liquid refrigerant during the frost operation. Therefore, compared to the conventional case where the accumulator alone requires a capacity capable of storing the amount of the separated liquid refrigerant, the storage capacity of the accumulator portion and the liquid receiving portion as the liquid storage container can be reduced and downsized. The space required for installation is reduced, and as a result, the device can be downsized.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a multi-type air conditioner configured by applying the present invention, and FIGS. 2 to 5 are first, second, and third liquid reservoir units interposed in the air conditioner, respectively. Third,
FIG. 13 is a schematic diagram illustrating a configuration according to a fourth embodiment. 1 ... Compressor, 2 ... Discharge pipe (discharge gas pipe), 3 ...
... Suction pipe (suction side gas pipe), 8 ... Outdoor heat exchanger (evaporator), 9 ... First electric expansion valve (First flow control valve), 10
... liquid pipe (liquid side pipe), 12 ... second electric expansion valve (second flow control valve), 13 ... liquid branch pipe (liquid side pipe), 15 ... indoor heat exchanger (condenser), 18 …… Accumulator section, 19 ……
Liquid receiving unit, 21: defrost opening / closing valve, 22: bypass pipe, 39 ... opening / closing valve (opening / closing means), 40 ... operation control device (defrosting operation control means).

Claims (1)

(57) [Claims] 1. A compressor (1) is provided with a discharge side gas pipe (2), a condenser (15), a liquid side pipe (10) (13), an evaporator (8), and a suction side gas pipe (3) in order. Connected to form a refrigerant circulation circuit, an accumulator section (18) is connected to the suction-side gas pipe (3), and a first port is sequentially connected to the liquid-side pipes (10) and (13) from the evaporator (8) side. Flow control valve (9), liquid receiving part (1
9) and a second flow control valve (12), respectively, and further, the first flow control valve (9) in the liquid side pipe (10).
The evaporator (8) side is connected to the discharge side gas pipe (2) by a bypass pipe (22) provided with a defrost opening / closing valve (21).
Wherein the accumulator section (18) and the liquid receiving section (19) are connected to each other through a communication flow path provided with an opening / closing means (39). When the means (39) is opened, the liquid refrigerant in the accumulator section (18) moves to the liquid receiving section (19) through the communication flow path, and the defrost opening / closing valve (21) is opened. During the defrosting operation in which the refrigerant discharged from the compressor (1) is returned from the bypass pipe (22) to the compressor (1) through the evaporator (8), the first and second flow control valves are operated. (9) A refrigeration system comprising a defrosting operation control means (40) for closing the valve (12) and opening the opening / closing means (39).