JPH02219968A - Refrigerating plant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a refrigeration system.

(Prior art) For example, in Japanese Patent Application Laid-Open No. 62-266361, multiple indoor units each having an indoor heat exchanger are connected in parallel to one outdoor unit having a compressor and an outdoor heat exchanger. A multi-type air conditioner configured by being connected to is described. In this system, defrosting operation to remove frost that has grown on the outdoor heat exchanger during heating operation is performed by a so-called positive cycle defrost method, in which the refrigerant discharged from the compressor is directly supplied to the outdoor heat exchanger. is being done. In such a defrosting operation cycle, the liquid refrigerant that radiates heat and condenses in the outdoor heat exchanger is separated from the gas component in an accumulator installed in the suction pipe of the compressor and stored in this accumulator. .

On the other hand, in the multi-type air conditioner as described above, there is a large difference in the required amount of circulating refrigerant between, for example, when the heating operation is performed simultaneously in all rooms and when it is performed only in one room. Therefore, normally, the piping route is filled with the amount of refrigerant required for circulation during operation in all rooms, and a liquid receiver is interposed in the liquid side piping that connects the outdoor heat exchanger and each indoor heat exchanger. During operation that produces a surplus, the surplus refrigerant is stored in the liquid receiver, so that operation is performed with an amount of refrigerant circulated according to the number of operating rooms on each indoor side.

(Secret B to be solved by the invention) By the way, during steady operation of heating or cooling, relatively little liquid refrigerant is separated from the circulating refrigerant by the accumulator, and most of the liquid refrigerant is separated during defrosting operation by positive cycle defrost as described above. Liquid refrigerant is separated in the accumulator. Therefore, in accordance with the amount of separated liquid refrigerant at this time, a large-sized accumulator is usually provided which has a storage capacity comparable to the total filling amount. On the other hand, in order to store the large amount of surplus refrigerant generated when only one chamber is operated as the liquid receiver described above, it is necessary to have an internal capacity close to the total filling capacity.
As a result, when these two liquid storage containers, the accumulator and the liquid receiver, are installed inside the outdoor unit, each requires a large dedicated space, creating the problem that the device cannot be made sufficiently compact. There is.

The present invention has been made in view of the above, and an object thereof is to provide a refrigeration device that can reduce the storage capacity of the liquid storage container as described above, thereby making the device more compact. .

(Means for Solving the Problems) Therefore, in the refrigeration system of the present invention, a discharge side gas pipe 2, a wiping condenser 15, a liquid side pipe 10, 13, an evaporator 8, and a suction side gas pipe 3 are sequentially connected to the compressor 1. They are connected to form a refrigerant circulation circuit, and an accumulator part 18 is connected to the suction side gas pipe 3, and a flow rate control valve 9 and a liquid receiving part are connected to the liquid side pipe 10 and the pipe 3 from the evaporator 8 side. 19, second flow control valve 12
are connected to the discharge side gas pipe 2 through a bypass pipe 22 in which a defrost on-off valve 21 is interposed, which is closer to the evaporator 8 than the first flow control valve 9 in the liquid side pipe 10. The accumulator section 18 and the liquid receiving section 19 are connected to each other via a communication channel in which an opening/closing means 39 is provided, and the opening/closing means 3
9 is opened, the liquid refrigerant in the accumulator section for one day is configured to move to the liquid receiving section 19 through the communication flow path, and further, the defrost on-off valve 21 is opened to prevent the liquid refrigerant from being discharged from the compressor 1. During a defrosting operation in which the refrigerant is returned to the compressor 1 from the bypass pipe 22 through the evaporator 8,
Defrosting operation control means 40 is provided for closing the first and second flow control valves 9.12 and opening the opening/closing means 39.

(Function) In the refrigeration system having the above configuration, during the defrosting operation of the evaporator 8, the liquid receiving part 19 is in a state of communicating only with the accumulator part 18, and therefore in this state, the liquid receiving part 19 is in communication with only the accumulator part 18.
functions as a storage section for liquid refrigerant separated in the accumulator section 18. In other words, the liquid refrigerant separated in one day from the accumulator section moves and is stored in the liquid receiving section 19 as well as within the accumulator section 18. The total internal capacity of the refrigerant and the liquid part 19 can be configured to be a storage capacity corresponding to the amount of liquid refrigerant separated in the accumulator part 19 during defrosting operation.

(Example) Next, a specific example of the refrigeration apparatus of the present invention 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. In the figure, X is an outdoor unit, and a compressor 1 is installed in this outdoor @ The compressor 1 has a discharge pipe 2 and a suction pipe 3 connected to a four-way switching valve 4, respectively. Note that the compressor 1 has an inverter 5 for adjusting its rotational speed, that is, its compression capacity by f#IJB. One switching port of the four-way switching valve 4 is connected to a first gas pipe 6, an outdoor heat exchanger 8 equipped with an outdoor fan 7, and a first electric expansion valve (
A liquid pipe 10 having a first flow rate control valve (1st flow rate control valve) 9 is connected in sequence, and a second
A gas pipe 11 is connected.

The tip of the liquid pipe 10 is connected to three liquid branch pipes 13, 13 in which second electric expansion valves (second flow rate control valves) 12, 12 are interposed, respectively, and the tip of the second gas pipe 11 is An indoor heat exchanger (indoor heat exchanger ( (only the indoor unit A is shown) are connected in parallel to each other by connecting pipes 16, 16, respectively. Indoor fans 17, 17 are attached to each of the indoor heat exchangers 15, 15, respectively. In the above example, the four-way switching valve 4 is installed to enable switching between cooling and heating, but during heating operation, which will be described later, each indoor heat exchanger 15 functions as a condenser and the outdoor heat exchanger 8 functions as an evaporator. At the same time, the discharge pipe 2 and the second gas pipe 11 constitute a discharge side gas pipe, and the suction pipe 3 and the first gas pipe 6 constitute a suction side gas pipe. Further, the liquid pipe 10 and each liquid branch pipe 13 constitute legal piping.

Further, an accumulator section 18 of a liquid reservoir unit R, which will be described later, is connected to the suction side gas pipe, in the above case, the suction pipe 3.
is interposed, and the legal piping, in the above case, the liquid branch pipe 13, 13 side of the first electric expansion valve 9 in the liquid pipe 10,
A liquid receiving portion 19 of the liquid reservoir unit R is provided.

Further, the piping portion of the eight outdoor heat exchangers in the liquid pipe 10 is connected to the discharge piping 2 by a bypass piping 22 in which a defrost on-off valve 21 is interposed. Note that this bypass pipe 22 can also be configured to be connected to the second gas pipe 11 instead of the discharge pipe 2 described above.

FIG. 2 shows a schematic diagram of the structure of the liquid reservoir unit (R) in a first embodiment. As shown in the figure, the liquid reservoir unit R has an internal space of a substantially circular M-shaped sealed casing 31 divided into upper and lower parts by a partition plate 32, with an accumulator part 18 on the upper side and a liquid receiving part 19 on the bottom side. They are each configured as follows.

As described above, the accumulator section 18 interposed in the suction pipe 3 has an outlet side pipe 33 to which the pipe on the compressor l side of the suction pipe 3 is connected, and the suction pipe 3.
An inlet side pipe 34 to which the pipe on the four-way switching valve 4 side is connected is provided. The outlet side pipe 33 and the inlet side pipe 34 penetrate through the upper end of the casing 31 and have open ends at positions spaced apart from each other on the upper side inside the accumulator section 19. Further, the outlet pipe 33 is formed of a U-shaped tube having a U-shaped portion at a position close to the partition plate 32, and has a suction hole 35 bored at its lowest position.

When the compressor 1 is operated and the refrigerant is circulated, when the gas-liquid mixed refrigerant flows into the accumulator section 19 through the inlet pipe 34, the liquid component in the accumulator section 19 is divided into partitions 1/ii: 32 side to cause gas-liquid separation, and the gas refrigerant on the upper side flows from the open end of the outlet side pipe 33 to the compressor 1 through this outlet side pipe 33.

At the same time, the liquid refrigerant accumulated on the partition plate 32 is sucked out little by little into the compressor l through the suction hole 35, and is gasified by compression work within the compressor l.

On the other hand, the liquid receiving part 19 interposed in the liquid pipe 10 has first and second connection pipes 36 connected to the liquid pipe 10, respectively.
．． 37 are provided, and these first and second connecting pipes 36.
37 penetrate through the bottom side of the casing 31 and open into the liquid receiving portion 19, respectively. In this liquid receiving portion 19, the amount of surplus refrigerant in the refrigerant pipe is stored. For example, there is a large difference in the amount of circulating refrigerant required when heating all three rooms and when heating only one room. Normally, the amount of circulating refrigerant required when heating all rooms is filled into the piping path, and therefore the above In this case, the surplus refrigerant amount generated during one-room or two-room operation is stored in the liquid receiving section 19, and operation is performed with an amount of circulating refrigerant corresponding to the number of operating rooms on each indoor side. There is.

A communication pipe 38 that communicates the bottom side of the accumulator part 18 with the liquid receiving part 19 is externally connected to the casing 31 of the liquid reservoir unit) R.
8 is provided with an electromagnetic on-off valve (opening/closing means) 39. When this on-off valve 39 is opened, the liquid refrigerant accumulated in the accumulator section 18 is discharged from the communication pipe 3.
8 to cause movement toward the liquid receiving portion 19 due to its own weight.

In the air conditioner having the above configuration, the on-off valve 39 of the liquid reservoir unit R is closed, the four-way switching valve 4 is located at the switching position shown by the broken line in FIG. 1, and the refrigerant discharged from the compressor 1 is Circulation is made from the outdoor heat exchanger 8 to each indoor heat exchanger 15, 15, and the outdoor heat exchanger 8 is used as a condenser, and each indoor heat exchanger 15, 15
Cooling operation is performed by causing each to function as an evaporator, but below, for convenience, control of each operation of heating operation and defrosting operation will be explained.

For this purpose, as shown in FIG. 1, inside the outdoor unit
An operation control device 40 that also functions as a defrosting operation control means is provided, and heating is controlled from an indoor control device (not shown) installed in each indoor unit A to C to this operation control device 40. When the operation request signal is input, both the defrost on-off valve 21 and the on-off valve 39 of the liquid reservoir unit R are closed, the four-way switching valve 4 is placed in the switching position shown by the solid line in the figure, and the compressor 1 is started. By doing so, heating operation is started. In this heating operation, the refrigerant discharged from the compressor 1 is supplied from the discharge pipe 2, the four-way switching valve 4, and the second gas pipe 11 to each indoor heat exchanger 15.・0 that is condensed in 15 is then circulated through the liquid pipe 10 to the outdoor heat exchanger 8, and after being evaporated in this outdoor heat exchanger 8, the first gas pipe 6, the four-way switching valve 4, and the suction pipe 3 The water is returned to the compressor 1 through the In this case, the degree of superheating of the evaporative refrigerant is controlled by the first electric expansion valve 9, and the temperature of the condensed refrigerant at the outlet of each indoor heat exchanger 15, 15 is the same in each second electric expansion valve 12, 12. By controlling the amount of refrigerant distributed to each indoor heat exchanger 15, 15 is controlled so that the amount of refrigerant distributed to each indoor heat exchanger 15 is controlled. The second electric expansion valve 12 corresponding to the room where heating is stopped is set to the stop opening (opening that allows a small amount of refrigerant to flow in proportion to natural heat radiation in order to prevent liquid from returning to the pressure IW machine 1). be done.

During this heating operation, the on-off valve 39 of the liquid reservoir unit (H) is maintained in a closed state, so the accumulator section 18 and the liquid receiving section 19 function independently, and the accumulator section 18 is compressed. The liquid refrigerant separated from the return flow refrigerant to the machine 1 is stored, and the excess refrigerant in the refrigerant circulation path is stored in the liquid receiving part 19.

Then, when the heating operation described above is continued and frost is generated in the outdoor heat exchanger 8, and the amount of frost formation increases, the operation control device 40 switches to the defrosting operation. In this defrosting operation, the defrost on-off valve 21 is opened as described above, and the on-off valve 39 of the liquid reservoir unit R is also opened.
, close the second electric expansion valve 9.12. As a result, the refrigerant discharged from the compressor 1 is transferred from the discharge pipe 2 to the bypass pipe 22.
, is directly supplied to the outdoor heat exchanger 8 through the liquid pipe 10, and then returned to the compressor 1 via the first 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 applied to the outdoor heat exchanger 8, and defrosting is performed.

In the refrigerant circulation cycle during this defrosting operation, the liquid refrigerant that has radiated heat and condensed in the outdoor heat exchanger 8 is transferred to the accumulator section 18.
Therefore, a large amount of separated liquid refrigerant is generated in the accumulator section 18, but this separated liquid refrigerant also moves from the accumulator 18 to the liquid receiving section 19 and is stored therein. In other words, the first and second electric expansion valves 9.
By closing the valve 12 and opening the on-off valve 39, the liquid receiving part 19 is brought into a state where it communicates only with the accumulator part 18. Therefore, in this state, the liquid receiving part 19 is connected to the liquid separated by the accumulator part 18. It functions integrally as a refrigerant reservoir.

As a result, it is possible to continue the defrosting operation with a configuration in which the total internal capacity of the accumulator section 18 and the liquid receiving section 19 is comparable to the amount of separated liquid during the defrosting operation,
Thereby, the liquid reservoir unit R can be made smaller in shape than the dedicated space required by the conventional liquid receiver and accumulator.

When the above-mentioned defrosting operation is completed, the defrost on-off valve 21
At the same time, the opening/closing valve 39 of the liquid reservoir unit R is closed, and the opening degree of the first and second electric expansion valves 9.12 is controlled during the heating operation, thereby restarting the heating operation. Ru. At this time, the liquid refrigerant accumulated in the liquid receiving part 19 is appropriately added to the circulation path, and operation is started at the refrigerant circulation amount according to the heating load on the indoor side from the beginning of restart. Conventionally, the liquid refrigerant separated in the accumulator during defrosting operation was
After resuming heating operation, only a small amount of refrigerant was sucked out by the compressor, and therefore operation started with insufficient amount of circulating refrigerant, resulting in cases where sufficient heating capacity could not be obtained. It is also capable of providing sufficient heating capacity.

In the above device, the on-off valve 39 of the liquid reservoir unit R is opened when the operation is stopped, and when the operation is started, the first on-off valve 39 is opened while the on-off valve 39 is kept open.
Both the second electric expansion valves 9 and 12 are closed to start the compressor 1, and after this startup waiting operation is continued for a predetermined short time, the on-off valve 39 is closed, and the first and second electric expansion valves 9 and 12 are closed. Valve 9.12
On the other hand, the operation control device 40 performs the opening degree control during the heating operation described above to shift to steady operation.

According to the above control, first, when the operation is stopped, the accumulator section 18 of the liquid reservoir unit R is maintained in a state in which it is communicated with the liquid receiving section 19 through the communication pipe 38. As a result, the liquid refrigerant that had accumulated in the accumulator section 18 during the previous operation moves toward the liquid receiving section 19 due to its own weight throughout the three days of the communication pipe. Furthermore, during the above-mentioned start-up waiting operation, from the suction pipe 3 to the second gas pipe 11, to each indoor heat exchanger 1.
5. The suction force of the compressor acts on the piping paths leading to the closed second electric expansion valves 12 in each liquid branch pipe 13, and the liquid refrigerant accumulated in these piping paths flows into the accumulator section 18. At the same time, this recovered liquid refrigerant moves into the liquid receiving section 19 in the same manner as described above. Therefore, the liquid refrigerant that had accumulated in the accumulator section 18 and the piping path during the previous operation has been collected into the liquid receiving section 19, and then the steady operation is started. Therefore, similarly to when the heating operation is restarted after the defrosting operation is completed, the amount of circulating refrigerant commensurate with the heating load on the indoor side is ensured, and operation with improved heating capacity is started. By performing this liquid recovery operation into the liquid receiving part 19 at the time of start-up at the start of cooling operation, it is possible to start operation with improved cooling capacity in the same way as described above, and furthermore, the compressor In a device configured using the so-called reverse cycle defrost method, in which defrosting is performed by switching the refrigerant discharged from the outdoor heat exchanger to a cycle in which it is circulated from the outdoor heat exchanger to the indoor heat exchanger, each switching between heating and defrosting is performed. By occasionally performing the liquid recovery operation to the liquid receiving part 19, it is possible to perform an operation with improved defrosting ability and heating ability.

FIG. 3 shows a schematic diagram of the structure of a second embodiment of the liquid reservoir unit l-R. In this embodiment, instead of the on-off valve 39 in the liquid reservoir unit R of the first embodiment, a check valve 41 is interposed in the communication pipe 38 as an on-off means. The check valve 41 is configured to close when the pressure in the liquid receiving section 19 is higher than that on the accumulator section 18 side, and to remain open when the pressure is the same.

The operating state of the air conditioner in which the liquid reservoir unit l-R of the second embodiment is installed in the refrigerant piping path shown in FIG. If this is not occurring, and while the compressor 1 is operating with the first and 21st dynamic expansion valves 9.12 closed, the accumulator section 18 and one liquid receiving section are maintained at the same pressure. Therefore, the check valve 41 is maintained in an open state.

When the first and second dynamic expansion valves 9 and 12 are opened and the operation is switched to the refrigerant cycle during heating, for example,
The high pressure side pressure is introduced into the liquid receiving part 19, and the check valve 41 is automatically closed to close the accumulator part 18 and the liquid receiving part 19.
Communication with the device is cut off. Therefore, in the liquid reservoir unit I/R of the first embodiment, in order to control the operation of the on-off valve 39, electric circuit components such as a drive relay and a control circuit are further required. In the liquid reservoir unit R of the embodiment, the check valve 41
The communication state between the accumulator section 18 and the liquid receiving section 19 is automatically switched due to the above-mentioned operation stop, startup operation, and defrosting operation.
Liquid recovery can be performed with a simpler configuration.

In addition to the configuration of the liquid reservoir unit R of the second embodiment, FIG. The constructed liquid reservoir unit R of the third embodiment
A schematic diagram of the configuration is shown. In the air conditioner incorporating the liquid reservoir unit R of this third embodiment, the liquid receiving part 19
When the operation shifts from a steady operating state in which a high-low differential pressure state occurs between the accumulator section 18 and the accumulator section 18 to a stop state, pressure equalization occurs between the accumulator section 18 and the liquid receiving section 19 through the pressure equalizing pipe 43, and this As a result, the pressure inside both parts 18 and 19 quickly changes to the same pressure state, so the check valve 41 opens immediately after the operation is stopped, and the receiving part of the liquid refrigerant accumulated in the accumulator part 18. The movement to the 19 side will be carried out promptly. Further, the pressure within the entire refrigerant piping path after the operation is stopped can be quickly equalized through the pressure equalization piping.

Furthermore, FIG. 5 shows a schematic diagram of the structure of the liquid reservoir unit R of the fourth embodiment. In this liquid reservoir unit H, an accumulator part 18 and a liquid receiving part 19 are provided on the partition plate 32.
A through hole 44 is bored to communicate with the through hole 44, and an on/off valve 45 containing a shape memory alloy as an opening/closing means is provided at a position on the side of the liquid receiving portion 19 facing the through hole 44. The shape memory alloy, which expands and contracts in response to temperature changes, takes an expanded form at a high temperature of, for example, 20° C. or higher, and at this time, the internal valve body of the on-off valve 45 comes into contact with the partition plate 32, causing the through hole to pass through. While closing the hole 44, the shape memory alloy changes to a reduced shape at a low temperature below 20°C, and at this time, the internal valve body separates from the partition plate 32 and connects with the accumulator part 18 through the through hole 44. It is configured to communicate with the liquid receiving part 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 operation, high-temperature condensed refrigerant is introduced into the liquid receiving part 19, and the on-off valve 45 cools the through hole 44 and is kept in a closed state, and at other times, the through hole 44 is kept closed.
The state is automatically changed to a state in which the accumulator section 18 and the liquid receiving section 19 communicate with each other through. Therefore, in this case as well, the liquid collection to the liquid receiving section 19 during the above-mentioned operation stop, startup operation, and defrosting operation is controlled to switch the communication state between the accumulator section 18 and the liquid receiving section 19. This can be done without separately providing circuit parts, etc., and the configuration can be simplified.

Although the above description has been made using an air conditioner for heating and cooling as an example, the present invention can also be applied to, for example, an air conditioner exclusively for heating or other refrigeration equipment. In the above description, an example has been described in which the accumulator section 18 and the liquid receiving section 19 are provided in the same casing 31, but a structure in which the accumulator section and the liquid receiving section are configured separately and connected to each other is explained. It is also possible to do the following.

(Effects of the Invention) As described above, in the refrigeration system of the present invention, during defrosting operation, the liquid receiving section functions as a storage section for liquid refrigerant separated by the accumulation section, so the total content of both is The amount can be configured to be approximately comparable to the amount of separated liquid refrigerant during the defrosting operation. Therefore, compared to the conventional case where the accumulator alone required a capacity to store the amount of separated liquid refrigerant, the storage capacity of the accumulator part and the liquid receiving part as a liquid storage container can be reduced and the size can be reduced. As a result, the required space for the cast member is reduced, and as a result, the device can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit diagram of a multi-type air conditioner constructed by applying the present invention, and FIGS. Third,
FIG. 7 is a schematic configuration diagram in a fourth embodiment. l...Compressor, 2...Discharge piping (discharge side gas pipe),
3... Suction pipe (suction side gas pipe), 8... Outdoor heat exchanger (evaporator), 9... First electric expansion valve (first flow rate control valve), 10... Liquid pipe ( liquid side piping), 12...2nd
Electric expansion valve (second flow control valve), 13... Liquid branch pipe (liquid side piping), 15... Indoor heat exchanger (1! Compressor), 18
...Accumulator section, 19...Liquid receiving section, 21.
...Defrost on-off valve, 22...Bypass piping, 3
9... Opening/closing valve (opening/closing means), 40... Operation control device (defrosting operation control means).

Claims (1)

[Claims] 1. Compressor (1), discharge side gas pipe (2), condenser (15
), liquid side pipes (10), (13), evaporator (8), and suction side gas pipe (3) are connected in sequence to form a refrigerant circulation circuit, and an accumulator section (
18), and one flow rate control valve (9), a liquid receiving part (
19) and a second flow control valve (12), and furthermore, a defrost on-off valve (2) is provided on the liquid side piping (10) closer to the evaporator (8) than the first flow control valve (9).
A refrigeration system connected to the discharge side gas pipe (2) by a bypass pipe (22) provided with a bypass pipe (22), the refrigeration system comprising an opening/closing means ( When the opening/closing means (39) is opened, the liquid refrigerant in the accumulator section (18) passes through the communication channel and reaches the liquid receiving section (19). ), and further opens the defrost on-off valve (21) to transfer the refrigerant discharged from the compressor (1) from the bypass pipe (22) to the evaporator (8).
) during defrosting operation in which the first and second flow control valves (9) and (12) are closed and the opening/closing means (39) is opened during defrosting operation in which the flow is returned to the compressor (1) through Control means (40
).