JP3108933B2 - Multi-room air conditioner - Google Patents

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 for controlling the air conditioning of a plurality of indoor units by a single outdoor unit.

[0002]

2. Description of the Related Art In recent years, in a large building such as a building, an indoor unit is provided in each room, and individual distributed air conditioning in which air conditioning of a plurality of indoor units is controlled by one outdoor unit has become mainstream. Japanese Patent Application Laid-Open No. 62-271040 is well known as an example technique.

FIG. 2 is a block diagram showing the above-mentioned conventional multi-room air conditioner, wherein a denotes an outdoor unit, b and c denote indoor units, 1 denotes a refrigerant compressor (hereinafter simply referred to as a compressor), 2 is a four-way valve, 3 is a heat source side heat exchanger, 4 is a cooling expansion valve, 5 is a heating expansion valve, and 6 is a check valve for closing the cooling expansion valve 4 during cooling. Reference numeral 7 denotes a check valve for closing the heating expansion valve 5 during cooling, and reference numeral 8 denotes a first auxiliary heat exchanger, which is annularly connected to form a heat source side refrigerant cycle.

Reference numeral 9 denotes a second auxiliary heat exchanger integrated with the first auxiliary heat exchanger 8 for heat exchange, and reference numeral 10 denotes a refrigerant amount adjusting tank for adjusting the amount of refrigerant during heating and during cooling. ,
Reference numeral 11 denotes a refrigerant transport device having reversibility in which the direction of passage of the refrigerant is opposite during heating and during cooling.

[0005] Also, reference numerals 12a and 12b denote user side heat exchangers which are accommodated in the indoor units b and c, respectively, and have connection pipes d, d ', e and e'.
As a result, the second auxiliary heat exchanger 9, the refrigerant amount adjusting tank 10, and the refrigerant transport device 11 are annularly connected to each other to form a use-side refrigerant cycle.

[0006] As described above, the conventional multi-room air conditioner is configured and operates as described below. In FIG. 2, the solid arrows indicate the flow of the refrigerant in the cooling cycle, and the dashed arrows indicate the flow of each refrigerant in the heating cycle.

First, during the cooling operation, in the heat source side refrigeration cycle, the high-temperature, high-pressure gas compressed by the compressor 1 as shown by the solid line arrow passes through the check valve 6 and is depressurized by the cooling expansion valve 4. The four-way valve 2 absorbs heat and generates heat by the auxiliary heat exchanger 8.
And the compressor 1 is refluxed.

At this time, heat is exchanged between the second auxiliary heat exchanger 9 and the first auxiliary heat exchanger 8 in the use side refrigerant cycle, and the refrigerant gas in the use side refrigerant cycle is cooled and liquefied. Then, the liquefied refrigerant is sent to the use-side heat exchangers 12a and 12b through the connection pipes d and e to cool the room through the refrigerant amount adjusting tank 10 and the refrigerant transfer device 11. At this time,
The refrigerant gas absorbs heat to be gasified and returns to the second auxiliary heat exchanger 9 via the connection pipes d 'and e'.

On the other hand, in the heating operation, the flow of the refrigerant becomes a refrigerant cycle indicated by a broken line arrow. In the heat source side refrigerant cycle, the high-temperature, high-pressure refrigerant gas compressed by the compressor 1 passes through the four-way valve 2 and the first auxiliary heat exchanger. 8, heat release and condensation
The pressure is reduced by the heating expansion valve 5 through the check valve 7, absorbed by the heat source side heat exchanger 3, and returned to the compressor 1 through the four-way valve 2.

At this time, heat is exchanged between the second auxiliary heat exchanger 9 and the first auxiliary heat exchanger 8 in the use-side refrigerant cycle, and the liquefied refrigerant in the use-side refrigerant cycle is overheated. It is gasified and sent to the use side heat exchangers 12a and 12b via the connection pipes d 'and e'. Here, the gasified refrigerant that has radiated heat into the room and heated is liquefied, sent to the refrigerant transfer device 11 through the connection pipes d and e, and returned to the second auxiliary heat exchanger 9 through the refrigerant amount tank 10.

[0011]

However, in the conventional configuration described above, the indoor unit b,
When the combined capacity of the respective operating capacities of c is larger, for example, when a plurality of indoor units b and c exceeding 14.5 kW in total are connected to the outdoor unit a having a rated capacity of 14.5 kW, the cooling operation is performed. Since the amount of heat transferred from the side refrigerant cycle to the heat source side refrigerant cycle is larger than the heat release amount in the heat source side heat exchanger, the high pressure or low pressure of the heat source side refrigerant cycle increases, and the cooling operation stops, There has been a problem that the compressor may be damaged.

An object of the present invention is to provide a multi-room cooling and heating apparatus which solves the above-mentioned conventional problems.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a method for controlling the heat transfer of a refrigerant between a heat source side refrigerant cycle and a use side refrigerant cycle.
The process is performed between the first auxiliary heat exchanger and the second auxiliary heat exchanger that are integrally formed, and the second auxiliary heat exchanger included in the use-side refrigerant cycle is provided with a refrigerant bypass circuit. The passage of the refrigerant is controlled by information indicating that the heat source side high pressure or low pressure exceeds a predetermined value during cooling.

[0014]

According to the present invention, the present invention is applied to a multi-room cooling and heating apparatus in which the total operating capacity of the indoor unit is larger than the rated operating capacity of the outdoor unit, and the high pressure or the low pressure of the heat source side cooling cycle during cooling is reduced. When the set value is exceeded, the bypass circuit is opened based on the detection information to reduce the flow rate of the refrigerant, and also during heating, the bypass circuit is closed to prevent the circulation of the refrigerant, thereby preventing a decrease in the heating capacity. And always,
Normal air-conditioning operation becomes possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a multi-room cooling / heating apparatus according to the present invention. This shows a case where the indoor units g and h each having an operating capacity of 11.6 kW are connected to the outdoor unit f having a rated capacity of 14.5 kW, and the total operating capacity of the indoor units is larger than the rated capacity of the outdoor unit. .

In the figure, reference numeral 13 denotes a variable capacity compressor whose capacity can be controlled, and the operating frequency of which is changed by an inverter 14 according to the operating capacity of the indoor units g and h. Reference numeral 15 denotes a second auxiliary heat exchanger bypass circuit, which connects the upstream side and the downstream side of the second auxiliary heat exchanger 9 with a bypass pipe. 16 is a high pressure sensor for detecting the discharge pressure provided in the pipe on the discharge side of the variable capacity compressor 13, and 17 is the detection of the high pressure sensor 16 provided in the second auxiliary heat exchanger bypass circuit 15. This is an on-off valve whose opening and closing are controlled by a signal. Here, it is an electromagnetic valve.

A check valve 18 is provided in the second auxiliary heat exchanger bypass circuit 15. 19 is a thermistor that detects a temperature corresponding to a low pressure. Reference numeral 20 denotes a stacked heat exchanger, and the first auxiliary heat exchanger 8 and the second auxiliary heat exchanger 9
And are integrally formed. 21 is a heat source side refrigerant cycle, and 22 is a use side refrigerant cycle. The same parts as those in FIG. 2 are denoted by the same reference numerals.

The present invention is configured as described above, and operates as described below.

First, the total operating capacity of the indoor units g and h is 11.6 kW.
× 2, which is larger than the rated capacity of the outdoor unit f of 14.5 kW. Therefore, during the cooling operation (the flow of the refrigerant is indicated by a solid line arrow), the operating frequency of the variable capacity compressor 13 is increased by the inverter 14 from, for example, a 60 Hz operation to a 70 Hz operation.

In the stack type heat exchanger 20, the variable capacity compressor 13
The high-temperature, high-pressure gas compressed by the compressor flows into the four-way valve 2, is condensed in the heat source side heat exchanger 3, becomes a high-pressure liquid refrigerant, takes the check valve 6, is decompressed by the cooling expansion valve 4, and is stacked. The heat is exchanged with the use-side refrigerant cycle 22 in the heat exchanger 20 to evaporate into low-pressure gas, which is returned to the variable capacity compressor 13.

In the use side refrigerant cycle 22, the refrigerant transfer device 11
The refrigerant discharged from the air conditioner cools the room in the use side heat exchangers 12a and 12b via the connection pipes d and e, and passes through the connection pipes d 'and e' to the heat source side refrigerant cycle in the laminated heat exchanger 20. The refrigerant is cooled and liquefied by exchanging heat with 21, and returns to the refrigerant transport device 11 through the refrigerant amount adjusting tank 10. At this time, since the total operating capacity of the indoor units g and h is larger than the rated capacity of the outdoor unit f as described above, the stack type heat exchanger 20 moves from the use side refrigerant cycle 22 to the heat source side refrigerant cycle 21. The amount of transferred heat becomes larger than the amount of heat radiated by the heat source side heat exchanger 3, and the high pressure or the low pressure of the heat source side refrigerant cycle 21 increases.

Here, when it is detected that the high pressure detected by the high pressure sensor 16 has become equal to or higher than a preset upper limit, for example, 2.4 MPa, the on-off valve 17 is opened. Due to the opening, the refrigerant is bypassed by the second auxiliary heat exchanger bypass circuit 15, and the circulation amount of the refrigerant to the stacked heat exchanger 20 is reduced, and the heat transfer from the use-side refrigerant cycle 22 to the heat source-side refrigerant cycle 21 The volume is reduced and the high pressure is reduced.

When the high-pressure sensor 16 detects that the pressure has fallen below a preset lower limit pressure, for example, 1.8 MPa, the on-off valve 17 is closed. By repeating this operation, an excessive increase in the high pressure is prevented, and the normal operation is maintained.

Next, a heating operation (the flow of the refrigerant is indicated by a broken line arrow)
In this case, the total operating capacity of the indoor units g and h becomes larger than the rated capacity of the outdoor unit f. Therefore, the operating frequency of the variable capacity compressor 13 is changed by the inverter 14 from, for example, the operation at 60 Hz to the operation at 70 Hz. I do.

In the heat source side refrigerant cycle 21, as shown by a broken line arrow, the high temperature and high pressure gas compressed by the variable capacity compressor 13 passes through the four-way valve 2 and exchanges heat with the utilization side refrigerant cycle 22 in the laminated heat exchanger 20. As a high-pressure liquid refrigerant, which is decompressed by the heating expansion valve 5 through the check valve 7,
The heat is evaporated in the heat source side heat exchanger 3 to become a low temperature gas and returns to the variable capacity compressor 13. At this time, the refrigerant cannot flow into the second auxiliary heat exchanger bypass circuit 15 by the check valve 18.

In the use-side refrigerant cycle 22, the refrigerant from the refrigerant transfer device 11 passes through the refrigerant amount adjusting tank 10 and exchanges heat with the heat source-side refrigerant cycle 21 in the laminated heat exchanger 20 to absorb heat and gasify, as indicated by a broken arrow. Then, the room is heated by the use-side heat exchangers 12a and 12b through the connection pipes d 'and e' to radiate and liquefy and return to the refrigerant transfer device 11 through the connection pipes d and e.

During the heating operation described above, since the heat radiation from the heat source side refrigerant cycle 21 to the use side refrigerant cycle 22 is large, the high pressure or the low pressure of the heat source side refrigerant cycle does not increase.

As described above, according to the present invention, in the cooling operation in which the total operation capacity of the indoor unit is larger than the rated operation capacity of the outdoor unit, the high pressure sensor 16 detects an increase in the high pressure and performs the cooling operation. The on / off valve 17 is opened based on the detection information, and the refrigerant is bypassed by the second auxiliary heat exchanger bypass circuit 15 to reduce the circulation of the refrigerant to the stacked heat exchanger 20, thereby preventing the high pressure of the heat source side refrigerant cycle 21 from rising. And maintain normal operation.

When the low pressure rises during cooling, the low pressure rise is detected as a temperature rise by the thermistor 19, and the on-off valve 17 is opened based on the information to prevent the rise of the low pressure similarly to the above high pressure rise. Normal operation.

Further, according to the present invention, the operating frequency of the variable capacity compressor 13 is controlled and made to correspond to the operating capacity of the indoor unit by the inverter 14, so that the fine cooling capacity can be controlled. Further, since the first auxiliary heat exchanger and the second auxiliary heat exchanger are formed in the stacked heat exchanger 20, the heat exchanger is made compact and the cost is reduced.

[0032]

As described above, the multi-room air conditioner of the present invention can be bypassed to the second auxiliary heat exchanger when the total operation capacity of the indoor unit is larger than the rated operation capacity of the outdoor unit. By providing a circuit and its on-off valve and check valve, during cooling, when the high pressure of the heat source side cooling cycle, or low pressure exceeds a predetermined value set, open the on-off valve to reduce the flow rate of the refrigerant, Further, at the time of heating, the check valve is closed to prevent the circulation of the refrigerant to the bypass circuit, thereby preventing a decrease in the heating capacity. Therefore, it is a multi-chamber refrigerant heating apparatus that can always operate normally, and can be used in air conditioning that requires cooling and heating of a large number of rooms in a building or the like where a construction rush continues recently.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a multi-room air conditioner of the present invention.

FIG. 2 is a block diagram showing an example of a conventional multi-room air conditioner.

[Explanation of symbols]

2 ... four-way valve, 3 ... heat source side heat exchanger, 4 ... cooling expansion valve, 5 ... heating expansion valve, 6, 7, 18 ... check valve, 8
… First auxiliary heat exchanger, 9… Second auxiliary heat exchanger, 10… Refrigerant amount adjustment tank, 11… Refrigerant transport device, 12a, 12b… Usage side heat exchanger, 13… Variable capacity compressor, 14… Inverter , 15: bypass circuit of the second auxiliary heat exchanger, 16: high pressure sensor, 17: open / close valve, 19: thermistor, 20 ...
Stacked heat exchanger, 21: heat source side refrigerant cycle, 22: utilization side refrigerant cycle.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masao Kurachi 3--22, Takaidahondori, Higashiosaka-shi, Osaka, Matsushita Refrigeration Machinery Co., Ltd. (58) Field surveyed (Int.Cl. ⁷ , DB name) F24F 11 / 02 102 F25B 1/00 399 F25B 13/00

Claims (1)

(57) [Claims] 1. A heat-source-side refrigerant cycle in which a refrigerant compressor, a heat-source-side heat exchanger, an expansion valve, and a first auxiliary heat exchanger are connected in a ring shape, and integrally formed with the first auxiliary heat exchanger. A use-side refrigerant cycle in which the second auxiliary heat exchanger, the refrigerant transfer device, and the plurality of use-side heat exchangers are connected in a ring shape, and the passage of the refrigerant through the second auxiliary heat exchanger is bypassed. A multi-room air-conditioning apparatus characterized in that a second auxiliary heat exchanger bypass circuit is provided for bypassing when a high pressure or a low pressure of a heat source side refrigerant cycle exceeds a predetermined value during a cooling operation.