JPH03129260A - Multi-room type air conditioner - Google Patents

Abstract

PURPOSE:To operate the title air conditioner while maintaining optimum operational pressure conditions by constituting a refrigerant circulating path in the form of a ring, which connects an outdoor unit to a plurality of indoor units, and providing a bypass connecting a circulating path between a four-way valve and an outdoor heat exchanger to a circulating path between an outdoor expansion valve and indoor expansion valves. CONSTITUTION:In a case where the performance of indoor units is extremely small and a 1-HP operation is carried out, indoor side expansion valves 8a, 8b, 8c are closed while an indoor side expansion valve 8d is opened, and the performance of a compressor 2 shows a 2-HP operation in a lower limit. in this case, the pressure of condensation (or an equivalent temperature) is detected, and when it is lower than a preset value, a solenoid valve 15 is opened. Thereby, gas discharged from the compressor 2 is made to flow to two circulating paths i.e., a path to an outdoor side heat exchanger 4 and a bypass 17, and since condensation performance is reduced, the pressure of condensation is increased. In the case of the small capacity operation of the indoor units, an amount of refrigerant passing through the bypass 17 is controlled to reduce the condensation performance by controlling the opening degree of an outdoor expansion valve 5. This method makes it possible to carry out a cooling operation while always maintaining optimum operational pressure conditions throughout the year irrespective of the number of indoor units.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a multi-room air conditioner, and particularly to total control operation during cooling operation.

BACKGROUND ART Various developments have already been made regarding conventional multi-room air conditioners having multiple indoor units, such as Refrigeration, Vol. 61, No. 708 (October 1986 issue) Pl 0
Multi-room air conditioners such as those shown in 38 to 1045 will be explained with reference to 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 θ.

7a, 7b, 7c, 7d are indoor units, respectively, indoor expansion valves 8a, 8b, 8c, 8d, indoor heat exchangers 9a, 9b, 9c, 9d, and indoor side 7y710a.
, 10b, 10c, and 10d.

The outdoor unit 1 and the indoor units 7a, 7b, 7c, and 7d are connected in an annular manner by a liquid pipe 11 and a gas pipe 12 to form a refrigerant circuit 13.

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

First, during cooling operation, the high-temperature, r5-pressure gas compressed by the compressor 2 passes through the four-way valve 3, condenses in the outdoor heat exchange g34, becomes high-pressure liquid refrigerant, and passes through the outdoor expansion valve 5 to the indoor air. The pressure is reduced by the inner expansion valves 8a, 8b, 8c, and 8d, and the indoor heat exchangers 9a, 9b, sc, and 9d exchange heat with indoor air, evaporate, and become a low-temperature, low-pressure gas, which returns to the compressor 2. At this time,
When 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), and the indoor unit is operated so that no refrigerant flows through the stopped indoor unit. Ru.

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 and 90.9d, it exchanges heat with indoor air and condenses to become a high-pressure liquid refrigerant, which then enters the indoor expansion valves 8a and 8b.

The gas is depressurized by the outdoor expansion valve 5 via 8c and 8d, evaporated by the outdoor heat exchanger 4 to become a low-temperature, low-pressure gas, and returned 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 to be Solved by the Invention However, in recent years, there has been a strong demand for this type of multi-room air conditioner to provide cooling throughout the year, and it is desired that cooling operation be possible even under low outside temperature conditions in winter. If the operating indoor unit is operated at a small capacity (e.g. - unit operation), an imbalance will occur between the compressor function power and the outdoor heat exchanger capacity and the indoor heat exchanger capacity, resulting in There was a problem that the pressure state became abnormal.

That is, for example, 10" outdoor unit and 4H), 3I-P.

2) In a 10-seat multi-room air conditioner consisting of a combination of 1) P and 1E-P indoor units, 1) In the case of cooling operation with only the P indoor unit at low outside temperatures, the capacity is lower than that of the 11() indoor unit. Since the compression function is larger, the low pressure decreases, and because the outdoor temperature is low and the outdoor function is large, the high pressure decreases, which causes the low pressure to decrease further, and the evaporation temperature returns to normal operation. This will be significantly lower than that. Therefore, the amount of refrigerant circulating through the indoor unit is significantly reduced, resulting in a decrease in cooling capacity and the formation of frost, making cooling impossible.

The present invention solves the above-mentioned conventional problems, and provides a multi-room type that can maintain an appropriate operating pressure state even when cooling a small capacity indoor unit under low outside temperature conditions. The purpose is to provide air conditioners.

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. The outdoor heat exchanger and the outdoor fan and the indoor expansion valve are connected by a bypass circuit consisting of a solenoid valve and a flow rate adjustment mechanism.

Function The present invention, with the above-described configuration, enables cooling operation that always maintains an appropriate operating pressure state and condition 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. Incidentally, the same parts as those in the prior art are given the same reference numerals, and detailed explanation thereof will be omitted.

14 is an outdoor unit of a multi-room air conditioner, and compressor 2. Four-way valve 3. Outdoor heat exchanger4. Outdoor expansion valve6. An outdoor fan 6, a solenoid valve 16, and a flow rate adjustment mechanism 16 are provided.
Outdoor expansion valve 5 and indoor expansion valve 8a, 8b, 8c, 8d
and a bypass circuit 17 connecting between the four-way valve 3 and the outdoor heat exchanger 4.

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

Outdoor heat exchanger 4...10)P, indoor heat exchanger 9a----4)P, 9b--3)P, 9cm-
--2K).

9d...1 sweat, pressure m machine 2...,...2-10
) variable between P.

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

When the indoor functional power is 10)P, the solenoid valve 15 is closed, the compressor 2 is operated at 10H', and the capacities of the outdoor heat exchanger 4 and the indoor heat exchangers 9a, 9b, 9c, and 9d are balanced. Therefore, it is operated while maintaining an appropriate operating pressure.

Next, when the indoor functional capacity becomes extremely small and IH) operation is performed, the indoor expansion valves 8a, sb, and ac are closed, the indoor expansion valve 8d is opened, and the compressor 2 capacity is reduced to the lower limit of 2. It becomes driving. At this time, the condensing pressure (or equivalent temperature) is detected, and if it is lower than the set value, the solenoid valve 16 is opened. Then, the discharged gas from the compressor 2 flows through both the outdoor heat exchanger 4 and the bypass circuit 17, and the condensing capacity decreases, so that the condensing pressure increases.

However, even when the outside temperature is low and in the above state, the condensing pressure may be lower than the set value.

In this case, by further throttling the outdoor expansion valve 5, the amount of refrigerant flowing through the outdoor heat exchanger 4 is reduced and the bypass circuit 17
control to increase the sound of flowing refrigerant. Then, since the condensing capacity of the outdoor heat exchanger 4 further decreases, the condensing pressure increases.

As described above, when operating the indoor unit with a small capacity, the amount of refrigerant flowing through the bypass circuit 17 is controlled by controlling the opening degree of the outdoor expansion valve 6 to reduce the condensing capacity, and the indoor heat exchanger Since a drop in high pressure is prevented in a way that is balanced with capacity, a drop in low pressure is also suppressed, an extreme drop in evaporation temperature can be prevented, and the phenomenon of frost formation can be eliminated.

Effects of the Invention As is clear from the following description, the present invention has an outdoor unit consisting of a compressor, a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and an indoor expansion valve and an indoor heat exchanger. A ring-shaped refrigerant circuit is constructed by connecting multiple indoor units consisting of a solenoid valve and a flow rate between the liquid pipe between the outdoor expansion valve and the indoor expansion valve, the four-way valve, and the outdoor heat exchanger. Since the configuration is connected through a bypass circuit consisting of an adjustment mechanism, even under low outdoor temperature conditions such as during cooling operation in winter, the indoor functional power and outdoor functional power are maintained as if one indoor unit were operating. The resulting imbalance is resolved by lowering the condensing capacity, making it possible to maintain cooling operation at an appropriate operating pressure throughout the year, regardless of the number of indoor units in operation.

[Brief explanation of the drawing]

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, 6...Outdoor expansion valve, 7
a, 7b, 7c. 7d... Indoor unit, 8a, 8b, 8c, ad...
... Indoor expansion valve, sa, 9b, sc, sd...
... Indoor heat exchanger, 13 ... Refrigerant circuit, 1
4...Outdoor unit, 15...Solenoid valve, 16.
...Flow rate adjustment mechanism, 17...Bypass circuit.

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, and a plurality of indoor units consisting of an indoor expansion valve and an indoor heat exchanger, A multi-chamber type provided with a bypass circuit comprising a solenoid valve and a flow rate adjustment mechanism that connects between the four-way valve and the outdoor heat exchanger and between the outdoor expansion valve and the indoor expansion valve. Air conditioner.