JPH0682113A - Multi-room air-conditioning apparatus - Google Patents

Abstract

PURPOSE:To ensure stable operation of a system while always securing air- conditioning capability as desired by a method wherein a discharge temperature is detected and the opening or closing of a switching gear of a receiver tank is controlled in an outdoor machine based on the results of detection to eliminate the shortage of a refrigerant of the system. CONSTITUTION:An outdoor machine 21 is connected in parallel to a plurality of room machines 10 with a high pressure gas pipe 15, a low pressure gas pipe 16 and a liquid pipe 17. Here, the high pressure gas pipe 15 is connected to a receiver tank 8 of the liquid pipe 17 with a bypass pipe 9 through a switching gear 6 and a flow rate adjustor 7. One hand of room side heat exchangers 12 (a-c) is connected to the high pressure gas pipe 15 or the low pressure gas pipe 16 free to switch with the opening or closing of high pressure side two-way valves 13 (a-c) and low pressure side two-way valves 14 (a-c). Moreover, the other hand of the room side heat exchangers 12 is connected to the liquid pipe 17 through room side expansion valves 11 (a-c). Discharge temperature is detected with a sensor 23. The opening or closing of a switching gear 6 is controlled by a control means 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-room air conditioner, and more particularly to a refrigeration cycle for a multi-room air conditioner in which cooling and heating can be freely selected for each indoor unit.

[0002]

2. Description of the Related Art Conventionally, as a multi-room type air conditioner of this type, for example, there is one disclosed in Japanese Patent Laid-Open No. 3-63467.

The conventional multi-room air conditioner of the above-mentioned publication will be described below with reference to the drawings.

In FIG. 4, reference numeral 1 denotes an outdoor unit of a multi-room air conditioner, which includes a compressor 2, a three-way valve 3 as a three-way switching mechanism, an outdoor heat exchanger 4, an outdoor expansion valve 5, and an opening / closing device 6. ,
It is composed of a flow rate adjusting device 7, a receiver tank 8 and a bypass pipe 9. An indoor unit 10 has an indoor expansion valve 1
1, an indoor heat exchanger 12, a high pressure two-way valve 13, and a low pressure two-way valve 14.

One of the indoor heat exchangers 12 communicates with a high-pressure gas pipe 15 connecting the high-pressure side of the outdoor unit 1 and the indoor unit 10 via a high-pressure two-way valve 13, and a low-pressure two-way valve. The low pressure side of the outdoor unit 1 is communicated with the low pressure gas pipe 16 connecting the indoor unit 10 via 14, and the high pressure side two-way valve 13
By opening and closing the low pressure side two-way valve 14 and the indoor side heat exchanger 12
One of them is switchably connected to the high pressure gas pipe 15 or the low pressure gas pipe 16.

The other of the indoor heat exchangers 12 communicates with the liquid pipe 17 connecting the liquid pipe portion of the outdoor unit 1 and the indoor unit 10 via the indoor expansion valve 11.

Further, the high pressure gas pipe 15 and the receiver tank 8 provided in the liquid pipe 17 are connected by a bypass pipe 9 via an opening / closing device 6 and a flow rate adjusting device 7. 18
Is an outdoor controller, which comprises an outside air temperature detecting means 19 and an opening / closing device controlling means 20. It should be noted that three indoor units 6 are connected in this conventional example, and the subscripts a, b, and c are added to distinguish them.

FIG. 7 is a block diagram of a conventional multi-room air conditioner, and FIG. 8 is a control flow chart of the switchgear 6.

Next, the control of the opening / closing device 6 will be described with reference to FIGS. 7 and 8. First, the compressor 2 starts operating (step 1), and it is determined whether the cooling operation or the heating operation is operating (step 2). In the case of the cooling operation, the outside air temperature detecting means 19 first detects the outside air temperature,
It is judged whether the temperature is below a preset temperature (step 3). If the temperature is below the preset temperature, the switchgear control means 20 opens the switchgear 6 (step 4). If the temperature is higher than the preset predetermined temperature, the switchgear control unit 20 causes the switchgear 6 to be in the closed state (step 5).

Next, the operation of the multi-room air conditioner having the above structure will be described. First, the case of only the cooling operation will be described. The flow of the refrigerant in this case is indicated by solid arrows, and the open / closed states of the valves are as follows. That is, the high pressure side two-way valve 13
Is closed, the low pressure side two-way valve 14 is open, and each indoor expansion valve 11 has an opening degree corresponding to each indoor load.

The refrigerant discharged from the compressor 2 is a three-way valve 3
Is condensed and liquefied in the outdoor heat exchanger 4 and is led to the liquid pipe 17 through the outdoor expansion valve 5. And the indoor expansion valve 1
1 through each of the indoor heat exchangers 12 to evaporate and vaporize, respectively, and then through the low pressure side two-way valve 14 to the low pressure gas pipe 1
Guided to 6. Then, it returns to the compressor 2 and performs a cooling operation.

When the outside air temperature is low, the opening degree of the outdoor expansion valve 5 is reduced to increase the high pressure. Then, by decreasing the opening degree of the outdoor expansion valve 5, the liquid refrigerant pressure decreases, but the outside air temperature is the outside air temperature detecting means 19
When the temperature is lower than a predetermined temperature, the switchgear control means 20 causes the switchgear 6 to open, the high-pressure gas refrigerant is guided to the receiver tank 8 through the high-pressure gas pipe 15, and the liquid refrigerant pressure becomes a predetermined value. Holds in value. As a result, the differential pressure before and after the indoor expansion valve 11 becomes sufficient, a sufficient amount of refrigerant circulation can be secured, and a predetermined cooling capacity can always be secured.

Next, the case of only the heating operation will be described. The flow of the refrigerant in this case is indicated by a dashed arrow, and the open / closed state of each valve is as follows. That is, the high-pressure two-way valve 13 is open, the low-pressure two-way valve 14 is closed, and each indoor expansion valve 11 has an opening degree according to each indoor load.

The refrigerant discharged from the compressor 2 is passed through the high-pressure gas pipe 15 and the high-pressure side two-way valve 13 to each indoor heat exchanger 1
2, is condensed and liquefied there, flows into the liquid pipe 17 through the indoor expansion valve 11, is depressurized to a low-pressure two-phase state by the outdoor expansion valve 5, enters the outdoor heat exchanger 4, and is evaporated and vaporized. To do.
After that, it flows into the low-pressure gas pipe 16 through the three-way valve 3, returns to the compressor 2, and performs heating operation.

Next, the case of simultaneous cooling and heating operation in cooling only (hereinafter referred to as cooling only operation) will be described with reference to FIG. Here, the operating state of each indoor unit 10 is the indoor unit 10a,
10b ... Cooling, indoor unit 10c ... Heating, and the open / closed state of each valve is as follows. That is, the high pressure side two-way valves 13a, 13
b is closed, high pressure two-way valve 13c is open, low pressure two-way valve 14
a, 14b are open, the low pressure side two-way valve 14c is closed, and each indoor expansion valve 11 has an opening degree corresponding to each indoor load.

The refrigerant discharged from the compressor 2 is a three-way valve 3
Is condensed and liquefied in the outdoor heat exchanger 4 and is led to the liquid pipe 17 through the outdoor expansion valve 5. The remaining refrigerant is guided to the indoor heat exchanger 12c via the high-pressure gas pipe 15 and the high-pressure two-way valve 13c, where it is condensed and liquefied and flows into the liquid pipe 17 via the indoor expansion valve 11c. , Joins the refrigerant having passed through the outdoor heat exchanger 4. And the indoor expansion valve 11
After passing through a and 11b into the indoor heat exchangers 12a and 12b and evaporating and vaporizing respectively, the low pressure side two-way valve 14
It is led to the low pressure gas pipe 16 via a and 14b. afterwards,
Returning to the compressor 2, the cooling main operation is performed.

When the outside air temperature is low, the opening degree of the outdoor expansion valve 5 is reduced to increase the high pressure. Then, by decreasing the opening degree of the outdoor expansion valve 5, the liquid refrigerant pressure decreases, but the outside air temperature is the outside air temperature detecting means 19
When the temperature of the liquid refrigerant falls below a preset temperature, the switchgear control means 20 causes the switchgear 6 to open, the high-pressure gas refrigerant is guided from the high-pressure gas pipe 15 to the receiver tank 8, and the pressure of the liquid refrigerant is predetermined. Holds in value. As a result, the differential pressure before and after the indoor expansion valve 11 becomes sufficient, a sufficient amount of refrigerant circulation can be secured, and a predetermined cooling capacity can always be secured.

Next, a case of simultaneous heating / cooling operation (hereinafter referred to as heating-main operation) mainly in heating will be described with reference to FIG. Here, the operating state of each indoor unit 10 is the indoor unit 10a,
10b ... Heating, indoor unit 10c ... Cooling, and the open / closed state of each valve is as follows. That is, the high pressure side two-way valves 13a, 13
b is open, high pressure two-way valve 13c is closed, low pressure two-way valve 14
a, 14b are closed, the low pressure side two-way valve 14c is open, and each indoor expansion valve 11 has an opening degree corresponding to each indoor load.

The refrigerant discharged from the compressor 2 is guided to the indoor heat exchangers 12a and 12b through the high pressure gas pipe 15 and the high pressure two-way valves 13a and 13b, where it is condensed and liquefied and expanded indoors. It flows into the liquid pipe 17 through the valves 11a and 11b. Part of the refrigerant in the liquid pipe 17 flows into the indoor heat exchanger 12c through the indoor expansion valve 11c, is vaporized and evaporated, and then flows into the low pressure gas pipe 16 through the low pressure two-way valve 14c. The remaining refrigerant is decompressed by the outdoor expansion valve 5 to a low pressure two-phase state, enters the outdoor heat exchanger 4, and is evaporated and vaporized. After that, it flows into the low-pressure gas pipe 16 through the three-way valve 3,
After merging with the refrigerant that has passed through the low-pressure two-way valve 14c, it returns to the compressor 2 and performs heating-main operation.

[0020]

However, in the above-mentioned structure, during cooling operation, when the outside air temperature is detected and the temperature is equal to or lower than a preset predetermined temperature, the opening / closing device of the receiver tank is opened to reduce the cooling capacity. However, even when the outside air temperature is higher than the preset temperature, for example, when the capacity of the cooling operation indoor unit is small or the capacity of the cooling operation indoor unit and the heating operation indoor unit during the main cooling operation, When the difference is small, the opening degree of the outdoor expansion valve is reduced in order to reduce the capacity of the outdoor heat exchanger.

Therefore, a problem such as a system refrigerant shortage phenomenon occurs due to liquid refrigerant accumulating in the outdoor heat exchanger, and this problem cannot be solved only by detecting the outside air temperature, and stable operation of the system is ensured. It had the drawback that it could not be done.

When the capacity of the heating operation indoor unit is large during the heating operation or when the capacity difference between the heating operation indoor unit and the cooling operation indoor unit is large during the heating main operation, the set temperature of the heating operation indoor unit is The smaller the difference from the room temperature, the smaller the indoor expansion valve opening degree of the heating operation indoor unit.

As a result, there arises a problem that the refrigerant in the system runs short due to the liquid refrigerant accumulating in the indoor heat exchanger. However, the conventional example does not particularly describe the heating operation or the heating-main operation, and even in such a case, there is a drawback that the stable operation of the system cannot be ensured.

The present invention has been made in view of the above problems,
In the case where the amount of refrigerant in the system is insufficient by reducing the opening degree of the expansion valve on the outdoor side or the indoor side, the refrigerant circulation amount decreases, and the suction temperature or the discharge temperature rises rapidly. Paying attention to this fact, we adopted the discharge temperature as a means to detect the phenomenon of insufficient refrigerant in the system and the abnormality of the cycle.
The opening / closing device of the tank is opened, the refrigerant that has been accumulated in the receiver tank is discharged, the lack of refrigerant phenomenon in the system is resolved, and the system is operated at the optimum amount of refrigerant in that cycle. It is intended to provide a multi-room air conditioner capable of avoiding the phenomenon that the air conditioner stops and can freely cool and heat each indoor unit.

[0025]

In order to solve the above-mentioned problems, a multi-room air conditioner of the present invention is provided with a discharge temperature detecting means for detecting a discharge temperature and opens / closes the opening / closing device by the discharge temperature. The configuration is provided with device control means.

[0026]

According to the multi-room air conditioner of the present invention, the discharge temperature is detected and the opening / closing device of the receiver tank is opened in all of the cooling operation, the cooling-main operation heating operation, and the heating-main operation by the above-mentioned configuration. The refrigerant accumulated in the receiver tank is discharged to eliminate the refrigerant shortage phenomenon of the system.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multi-room air conditioner of the present invention will be described below with reference to the drawings. The same parts as those of the prior art will be designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 21 is an outdoor unit, 22 is an outdoor controller, which is composed of a discharge temperature sensor 23 as a discharge temperature detecting means and an opening / closing device control means 24.

Further, the high pressure gas pipe 15 and the receiver tank 8 installed in the branch pipe of the liquid pipe 17 are connected by a bypass pipe 9 via an opening / closing device 6 and a flow rate adjusting device 7.

Since the operation in such a configuration is the same as the conventional one, it is omitted here and only the control will be explained.

FIG. 2 is a block diagram of the multi-room air conditioner of the present invention, and FIG. 3 is a control flow chart of the switchgear 6.

Next, the control of the opening / closing device 6 will be described with reference to FIGS. First, the compressor 2 starts its operation (step 1), the discharge temperature is detected by the discharge temperature sensor 23, and the predetermined temperature (for example, 80) is set in advance.
C.) or higher (step 2), and if the discharge temperature is 80.degree. C. or higher, the switchgear control means 24 opens the switchgear 6 (step 3). Furthermore, the discharge temperature is detected by the discharge temperature sensor 23, and it is judged whether the discharge temperature is equal to or lower than a preset predetermined temperature (for example, 70 ° C.) (step 4). Thus, the switchgear 6 is closed (step 5). When it is determined in step 2 that the discharge temperature is lower than 80 ° C., the opening / closing device control means 24 causes the opening / closing device 6 to be closed (step 6).

That is, in all of the cooling, cooling-main, heating, and heating-main operations, the discharge temperature rises when the cycle is abnormal due to the phenomenon of insufficient refrigerant in the system. But,
Since the discharge temperature is constantly monitored by the discharge temperature sensor 23, when the temperature exceeds a predetermined temperature (for example, 80 ° C.) set in advance, the opening / closing device control means 24 causes the receiver tank 8 to operate.
The opening / closing device 6 is opened, the refrigerant accumulated in the receiver tank until now is discharged, the refrigerant shortage phenomenon of the system is eliminated, and the system is always operated with the optimum amount of refrigerant in the cycle. It is possible to avoid the phenomenon that the system stops and to ensure stable operation of the system.

Further, when the discharge temperature becomes equal to or higher than a predetermined temperature set in advance, the opening / closing device 6 of the receiver tank 8 is controlled to be opened. By setting the discharge temperature at the set outside air temperature, the switchgear control means 24 can be used as in the conventional case.
Thus, the opening / closing device 6 is opened, the high pressure gas refrigerant is guided to the receiver tank 8 through the high pressure gas pipe 15, and the liquid refrigerant pressure is maintained at a predetermined value. As a result, the differential pressure before and after the indoor expansion valve 11 becomes sufficient, a sufficient amount of refrigerant circulation can be secured, and a predetermined cooling capacity can always be secured.

In this embodiment, the high-pressure gas pipe 15 and the liquid pipe 17 are connected by the bypass pipe 9 via the opening / closing device 6, the flow rate adjusting device 7 and the receiver tank 8. Alternatively, the high pressure gas pipe 15 and the receiver tank 8 provided in the liquid pipe 17 may be connected by the bypass pipe 9 via the opening / closing device 6 and the flow rate adjusting device 7.

[0036]

As is apparent from the above description, the present invention is provided with the discharge temperature detecting means for detecting the discharge temperature and the opening / closing device control means for opening / closing the opening / closing device according to the discharge temperature. Is.

Therefore, the multi-room air conditioner of the present invention detects the discharge temperature even when the cycle is likely to be abnormal due to the shortage of the refrigerant in the system in all the cooling, cooling-main, heating, and heating-main operations. The open / close device of the receiver tank is in the open state, the refrigerant that has been accumulated in the receiver tank until now is discharged, the refrigerant shortage phenomenon of the system is resolved, and it is always operated with the optimal refrigerant amount in that cycle, so it is always A desired cooling / heating capacity can be ensured, and a phenomenon in which the operation of the system is stopped can be avoided, and stable operation of the system can be ensured.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram of a multi-room air conditioner according to an embodiment of the present invention.

FIG. 2 is a block diagram of a multi-room air conditioner of the same embodiment.

FIG. 3 is a control flowchart of an opening / closing device of the multi-room air conditioner of the same embodiment.

FIG. 4 is a refrigeration cycle diagram of a conventional multi-room air conditioner.

FIG. 5 is a refrigeration cycle diagram showing a cooling main operation state of a conventional multi-room air conditioner.

FIG. 6 is a refrigeration cycle diagram showing a heating-based operation state of a conventional multi-room air conditioner.

FIG. 7 is a block diagram of a conventional multi-room air conditioner.

FIG. 8 is a control flowchart of a switchgear of a conventional multi-room air conditioner.

[Explanation of symbols]

 2 Compressor 3 Three-way valve 4 Outdoor heat exchanger 5 Outdoor expansion valve 6 Opening device 7 Flow rate adjusting device 8 Receiving tank 9 Bypass piping 10 Indoor unit 11 Indoor expansion valve 12 Indoor heat exchanger 13 High pressure side two way Valve 14 Low pressure two-way valve 15 High pressure gas pipe 16 Low pressure gas pipe 17 Liquid pipe 21 Outdoor unit 22 Outdoor controller 23 Discharge temperature sensor-24 Switchgear control means 2 Compressor 12 Indoor heat exchanger 3 Three-way valve 13 High pressure Side two-way valve 4 Outdoor heat exchanger 14 Low-pressure two-way valve 5 Outdoor expansion valve 15 High-pressure gas pipe 6 Switchgear 16 Low-pressure gas pipe 7 Flow rate regulator 17 Liquid pipe 8 Receiver tank 21 Outdoor unit 9 Bypass pipe 22 Outdoor controller 10 Indoor unit 23 Discharge temperature sensor-11 Indoor expansion valve 24 Opening / closing device control means

Claims (1)

[Claims] 1. An outdoor unit comprising a compressor, a three-way switching mechanism, an outdoor heat exchanger, an outdoor expansion valve, an opening / closing device, a flow rate adjusting device, and a receiver tank, and an indoor expansion valve and an indoor heat exchanger. A plurality of indoor units consisting of a high pressure gas pipe, a low pressure gas pipe and a liquid pipe are connected in parallel, the high pressure gas pipe and the receiver tank or the liquid pipe installed in the branch pipe of the liquid pipe. By connecting a bypass pipe via the switchgear and the flow rate adjusting device, the inside of the heat exchanger is connected to the interposed receiver tank, and one of the indoor heat exchangers has a high pressure with the high pressure gas pipe or the low pressure gas pipe. The switch is connected by opening and closing the side two-way valve and the low pressure side two-way valve, the other one of the indoor heat exchanger is connected to the liquid pipe via the indoor expansion valve,
A multi-chamber air conditioner provided with a discharge temperature detecting means for detecting a discharge temperature and provided with an opening / closing device control means for opening / closing the opening / closing device according to the discharge temperature.