JPH03230059A - Multi-room type air conditioner - Google Patents

Abstract

PURPOSE:To enable an operation always keeping a proper operating pressure state to be carried out irrespective of the number of operation of the indoor devices annually by a method wherein a bypassing circuit connecting between an outdoor expansion valve and the second outdoor expansion valve and between a four-way valve and an outdoor heat exchanger and a flow rate controlling mechanism capable of being fully opened arranged in the midway of the bypassing circuit are provided. CONSTITUTION:An outdoor device 14 of a multi-room type air conditioner is comprised of a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5, an outdoor fan 6, the second outdoor expansion valve 15 between an outdoor expansion valve 5 and the outdoor heat exchanger 4, a bypassing circuit 16 connecting the midway part between the four-way valve and the outdoor heat exchanger 4 and the between the outdoor expansion valve 5 and the second outdoor expansion valve 15, and a flow rate controlling mechanism 17 capable of being fully closed and arranged in the midway part of the bypassing circuit 16. In the event that a low volume operation of the indoor device is carried out, a degree of opening of the flow rate controlling mechanism 17 in the bypassing circuit 16 is controlled and at the same time a degree of opening of the second outdoor expansion valve 15 is controlled, thereby a capability of the outdoor heat exchanger 4 is controlled so as to enable a reduction in a high pressure to be restricted for a cooling operation and an increasing of the low pressure to be also restricted for a heating operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multi-room air conditioner, and more particularly to capacity control operation.

Conventional technology Various developments have already been made regarding conventional multi-room air conditioners having multiple indoor units.
Multi-room air conditioners such as those shown in Nos. 8 to 1o46 will be explained using FIG.

1 is an outdoor unit of a multi-room air conditioner, which includes a compressor 2, a four-way valve 3. Outdoor heat exchanger4. It consists of an outdoor expansion valve 5 and an outdoor fan 6.

7a, 7b, 7C, and 7d are indoor units, including indoor side 1 expansion valves 8a, sb, 8c, and sd, indoor side heat exchangers 9a, 9b, and 90.9d, and indoor side fans 10a and 10, respectively.
It consists of b, 10c, and 10d.

And outdoor unit 1 and indoor unit - ra, 7b, 7G, 7d
are connected in an annular manner by a liquid pipe 11 and a gas pipe 12, forming a refrigerant circuit 13.

Next, the operation of the multi-room air conditioner having the above configuration will be explained.

First, during cooling operation, high-temperature, high-pressure gas compressed by the compressor 2 passes through the four-way valve 3, condenses in the outdoor heat exchanger 4, becomes high-pressure liquid refrigerant, and passes through the outdoor expansion valve 6 to the indoor expansion valve. 8a
, sb, 8c, sd, and the indoor heat exchanger 9a,
It exchanges heat with indoor air at 9b, 9c, and 9d, evaporates, becomes low-temperature, low-pressure gas, and returns to the compressor 2. At this time, if any of the indoor units is in a stopped state (for example, the indoor unit 7a), its indoor expansion valve is closed (for example, the indoor expansion valve 8a is closed) to prevent refrigerant from flowing into the stopped indoor unit. is driven by.

Next, during heating operation, the high-temperature, high-pressure gas compressed by the compressor 2 is passed through the four-way valve 3 to the indoor heat exchanger 9a.

9b, 9c, and sd exchange heat with indoor air and condense to become a high-pressure liquid refrigerant, and the indoor expansion valves 8a, sb.

It is depressurized by the outdoor expansion valve 5 via 8c and 8ad, evaporated in the outdoor heat exchanger 4, becomes low temperature and low pressure, and returns to the compressor 2. At this time, if any of the indoor units is in a stopped state (for example, the indoor unit 7a), its indoor expansion valve is slightly opened (for example, the indoor expansion valve 8a is slightly opened), and most of the refrigerant is in the stopped indoor unit. It is operated so that it does not flow.

Problems that the invention aims to solve However, in recent years, this type of multi-room air conditioner has become popular.

There is a strong demand for air conditioning throughout the year, and it is desired that it be possible to operate the air conditioner in low outside temperature conditions in the winter, and to operate the heating operation in periods when the outside temperature is relatively high, such as the middle period between autumn and winter. In the above configuration, when the operating indoor unit among the multiple indoor units is operated at a small capacity (for example, - unit operation), an unbalance occurs between the compressor function power and the outdoor heat exchanger capacity, and the operating pressure state changes. There was a problem with it becoming abnormal.

That is, for example, 10H) outdoor unit, 4)P, 3)P
.

In a 10H) multi-room air conditioner consisting of a combination of 2) P and 1) P indoor units, 1) In the case of cooling operation with only the P indoor unit at low outside temperatures, compared to the capacity of the 1) P indoor unit, Because the compression function is larger, the low pressure decreases, and because the outside temperature is low and the outdoor function is large, the high pressure decreases, and this causes the low pressure to decrease further, and the evaporation temperature is lower than normal operation. This will result in a significant decline. As a result, the amount of refrigerant circulating through the indoor unit is severely reduced, resulting in a decrease in cooling capacity and the formation of frost, making cooling impossible.

In addition, in the case of heating operation at high outside temperatures in the above operation example, contrary to the above cooling operation, the high pressure increases and the high pressure protection is activated, and the low pressure increases and exceeds the allowable operating range of the compressor. This caused damage to the compressor.

The present invention solves the above-mentioned conventional problems, and maintains an appropriate operating pressure state even when operating a small-capacity indoor unit in cooling operation under low outside temperature conditions or heating operation under high outside temperature conditions. The purpose of the present invention is to provide an indoor air conditioner that can be operated.

Means to solve problems In order to solve the above problems, the present invention provides a compressor.

An outdoor unit consisting of a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve is connected to a plurality of indoor units consisting of an indoor expansion valve and an indoor heat exchanger to form a ring-shaped refrigerant circuit, and the outdoor unit A second outdoor expansion valve is disposed between the expansion valve and the outdoor heat exchanger, and between the outdoor expansion valve and the second outdoor expansion valve, and between the four-way valve and the outdoor heat exchanger. A bypass circuit is provided for connection to the exchanger, and a flow rate control mechanism that can be completely closed is provided in the middle of the bypass circuit.

Function The present invention, with the above-described configuration, allows operation in which a proper operating pressure state is always maintained throughout the year, regardless of the number of indoor units in operation.

EXAMPLE An example of the present invention will be described below with reference to FIG. In addition, the same reference numerals are given to the same parts as in the conventional art, and detailed explanation thereof will be omitted.

14 is an outdoor unit of a multi-room air conditioner, and a compressor 2. Four-way valve 3. Outdoor heat exchanger4. Outdoor expansion valve 5. an outdoor side fan 6; a second outdoor expansion valve 15 provided between the outdoor side expansion valve 5 and the outdoor side heat exchanger 4;
Between the outdoor expansion valve 16 and the four-way valve 3 and the outdoor heat exchanger 4
Bypass circuit 16 and bypass circuit 16 connecting between
It consists of a fully closable flow rate control mechanism 17 provided midway through the flow control mechanism.

In addition, in this description, the capacities of each heat exchanger and compressor are shown below as examples.

Outdoor heat exchanger 4...10H), indoor heat exchanger 9a...---9If, 9b---3
H), 9 c----・2 IP, 9 +...
...11P, Compressor...Variable between 2 and 10) p.

Next, regarding the operation of the above configuration, first, cooling operation under low outside temperature conditions will be described.

When the indoor functional power is 10H', the flow rate control mechanism 17 is closed, the outdoor expansion valve 6 and the second outdoor expansion valve 15 are fully opened, and the indoor expansion valves 8a, sb, 8c.

8d, the compressor 2 is operated 1o)P while controlling the flow rate;
Outdoor heat exchanger 4 and indoor heat exchangers 9a and 9b.

Since the sc and sd capacities are balanced, they are operated while maintaining an appropriate operating pressure.

Next, when the indoor functional power becomes extremely small and 1) p operation is performed, the indoor expansion valves 8a, sb, and 8c are closed, the indoor expansion valve 8d controls the flow rate, and the compressor 2 is operated at the lower limit capacity. 2) It becomes p operation.

At this time, the condensing pressure (or equivalent temperature) is detected, and if it is lower than the set value, the flow rate control mechanism 17 is opened and the discharged gas from the compressor 2 is routed to both the outdoor heat exchanger 4 and the bypass circuit 16. At the same time, the flow rate of refrigerant flowing through the outdoor heat exchanger 4 and the bypass circuit 16 is controlled by adjusting the opening degrees of the flow rate control mechanism 17, the outdoor expansion valve 5, and the second outdoor expansion valve 15. to control the condensing capacity and bring the condensing pressure close to the set value.

Next, heating operation under high outside temperature conditions will be explained.

When the indoor functional power is jow, the flow control mechanism 17 is closed, the indoor expansion valves 8a, sb, 8c, and ad are fully opened, and the outdoor expansion valve 6 and the second outdoor expansion valve 16 are operated while controlling the flow rate. The compressor 2 is operated at 10)p, and has an outdoor heat exchanger 4 and an indoor heat exchanger 9a.

The capacities of 9b, 9C, and 9d must be balanced and operated while maintaining appropriate operating pressures.

Next, when the indoor functional power becomes extremely small and IH) operation is performed, the indoor expansion valves 8a, sb, and 8c are slightly opened, and the indoor expansion valve 8d and the outdoor expansion valve 6 are controlled while controlling the flow rate.
The compressor 2 is in 2)P operation at the lower limit capacity.

At this time, the evaporation pressure (or equivalent temperature) is detected, and if it is higher than the set value, the flow control mechanism 17 is opened and the low-pressure refrigerant from the outdoor expansion valve 5 is transferred to both the outdoor heat exchanger 4 and the bypass circuit 160. By flowing the fluid into the circuit and adjusting the opening degree of the flow rate control mechanism 17 and the second outdoor side 1 expansion valve 16,
The flow rate of refrigerant flowing through the outdoor heat exchanger 4 and the bypass circuit 16 is controlled to control the evaporation capacity and bring the evaporation pressure close to a set value.

As described above, in the case of small capacity operation of the indoor unit, by controlling the opening degree of the flow rate control mechanism 17 in the bypass circuit 16 and controlling the opening degree of the second outdoor expansion valve 16,
By controlling the capacity of the outdoor heat exchanger 4, it is possible to suppress a decrease in high pressure during cooling and to suppress an increase in low pressure during heating.

Effects of the Invention As is clear from the above description, the present invention comprises an outdoor unit consisting of a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and an indoor unit consisting of an indoor expansion valve and an indoor heat exchanger. A plurality of indoor units are connected to form an annular refrigerant circuit, a second outdoor expansion valve is disposed between the outdoor expansion valve and the outdoor heat exchanger, and the outdoor expansion valve and A bypass circuit connecting the second outdoor expansion valve and the four-way valve and the outdoor heat exchanger is provided, and a flow rate control mechanism that can be completely closed is provided in the middle of the bypass circuit. Since it was configured,
To enable operation that always maintains a proper operating pressure state regardless of the number of indoor units in operation throughout the year.

[Brief explanation of drawings]

FIG. 1 is a refrigeration cycle diagram of a multi-chamber air conditioner according to an embodiment of the present invention, and FIG. 2 is a refrigeration cycle diagram of a conventional multi-chamber air conditioner. 2... Compressor, 3... Four-way valve, 4...
...Outdoor heat exchanger, 5...Outdoor expansion valve, 7a, 7b, 7c. 7d... Indoor unit, 8a, sb, 8c, sd...
...Indoor expansion valve, 9a, sb, 9c, 9d...
... Indoor heat exchanger, 13 ... Refrigerant circuit,
14...Outdoor unit. 15...Second outdoor expansion valve, 16...Bipanu circuit, 1 completion...Flow control mechanism.

Claims (1)

[Claims] An annular refrigerant circuit is constructed by connecting an outdoor unit consisting of a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve to multiple indoor units consisting of an indoor expansion valve and an indoor heat exchanger. , a second outdoor expansion valve is disposed between the outdoor expansion valve and the outdoor heat exchanger, and between the outdoor expansion valve and the second outdoor expansion valve, and between the four-way valve and the A multi-room air conditioner is provided with a bypass circuit that connects an outdoor heat exchanger, and a flow rate control mechanism that can be completely closed in the middle of the bypass circuit.