JPH03129259A - 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 connecting a liquid tube between an outdoor expansion valve and indoor expansion valves to a tube between a four-way valve and an outdoor heat exchanger by a bypass provided with an electrically operated expansion valve. CONSTITUTION:In a case where the performance of indoor units becomes 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 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, an electrically operated expansion 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 16. At the same time, the flow rate of refrigerant passing through the outdoor side heat exchanger 4 and the bypass 16 is regulated by regulating the opening degree of the electrically operated expansion valve 15, and the pressure of condensation is made to approach the preset value while controlling the performance of condensation. 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 the Invention The present invention relates to a multi-room air conditioner, and more particularly to capacity control operation during cooling operation.

2. Description of the Related Art Various developments have already been made regarding conventional multi-room air conditioners having multiple indoor units, such as Refrigeration, Vol.
A multi-room air conditioner as shown in a to 1046 will be explained using FIG. 2.

1 is an outdoor unit of a multi-room air conditioner, 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, which include indoor expansion valves sa, sb, sc, and sd, and an indoor heat exchanger 9a, respectively.
, 9b, 9c', 9ti, indoor fan 10a
, 10b, 10a, 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, 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
, 8b, 8a, and 8d, and the indoor heat exchanger sa,
It exchanges heat with indoor air at 9b, sa, 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), so that no refrigerant flows 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 9d exchange heat with the indoor air and condense to become a high-pressure liquid refrigerant, which then passes through the indoor expansion valves Ba and sb.

The gas is depressurized by the outdoor expansion valve 6 via sc and ad, evaporated by the outdoor heat exchanger 4 to become 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 opened completely (for example, the indoor expansion valve 8a is slightly opened), and almost no refrigerant is left 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 (for example, - unit operation), an imbalance will occur between the compressor function power and the outdoor heat exchanger capacity and the indoor/outdoor heat exchanger capacity, and the operation will be interrupted. There was a problem that the pressure state became abnormal.

That is, for example, a 10W outdoor unit and 4)p, 3)p.

In a 10)p multi-room air conditioner consisting of a combination of 2)P and 1)p indoor units, in the case of cooling operation with only the 11() indoor unit at low outside temperatures, 1) the capacity of the P indoor unit Comparatively, the compression function is larger, so the low pressure decreases, and the outdoor temperature is low and the outdoor function is large, so the high pressure decreases, and this influences 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 air conditioner that enables operation while maintaining an appropriate operating pressure state even when a small capacity indoor unit is operated for cooling under low outside temperature conditions. The purpose is to provide a machine.

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

An annular refrigerant circuit is constructed by connecting an outdoor unit consisting of a four-way valve, an outdoor heat exchanger, and an outdoor expansion valve, and multiple indoor units consisting of an indoor expansion valve and an indoor heat exchanger. A bypass circuit is provided to connect the outside heat exchanger and between the outdoor expansion valve and the indoor expansion valve, and an electric expansion valve is disposed in the middle of this bypass circuit.

Function The present invention enables cooling operation that always maintains a proper IK positive pressure state throughout the year, regardless of the number of indoor units in operation, due to the above-mentioned roof structure.

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, which includes a compressor and a compressor;
Four-way valve 3. Outdoor heat exchanger4. Outdoor expansion valve6. An outdoor expansion valve 6 including an outdoor fan 6 and an electric expansion valve 16
and indoor expansion valves Ba, sb.

It consists of a liquid pipe 11 between sa and sd, a bypass circuit 16 connecting between the four-way valve 3 and the outdoor heat exchanger 4.

In addition, 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 9&...4H>, 9b...3)p,
9c...2IP.

9d...1H), compressor 2...2-1
Variable during 01P.

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

When the indoor functional power is 101P, the electric expansion valve 16 is closed, the compressor 2 is operated for 10H', and the outdoor (I\lI heat exchanger 4 and indoor heat exchanger 9a, 9b, 9G, 9d
Since the capacity of the pump is balanced, it is operated while maintaining an appropriate operating pressure.

Next, when the indoor functional capacity becomes extremely small and 11() operation is performed, the indoor expansion valves 8a, sb, and 8c are closed, the indoor expansion valve 8d is opened, and the compressor 2 capacity is reduced to the lower limit of 2.
H) Driving.

At this time, the condensing pressure (or equivalent temperature) is detected, and if it is lower than the set value, the electric expansion valve 15 is opened, and the discharged gas from the compressor 2 is sent to both the outdoor heat exchanger 4 and the bypass circuit 160. At the same time, by adjusting the opening degree of the electric expansion valve 16, the flow rate of refrigerant flowing through the outdoor heat exchanger 4 and the bypass circuit 16 is adjusted, and the condensing pressure is brought close to the set value while controlling the condensing capacity. .

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, the electric expansion valve 15 is fully opened and the outdoor expansion valve 5 is further throttled to reduce the flow rate of refrigerant flowing through the outdoor heat exchanger 4 and increase the flow rate of refrigerant flowing through the bypass circuit 16. Then, since the condensing capacity of the outdoor heat exchanger 4 further decreases, the condensing and condensing pressure increases.

As described above, in the case of small capacity operation of the indoor unit, the opening degree of the electric expansion valve 16 in the bypass circuit 16 is controlled, and
By controlling the opening degree of the outdoor expansion valve 5, the flow rate of refrigerant flowing through the bypass circuit 16 is controlled to reduce the condensing capacity and to balance with the indoor heat exchanger capacity to prevent a drop in high pressure. It also suppresses a drop in low pressure, prevents an extreme drop in evaporation temperature, and eliminates frost formation.

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 ring-shaped refrigerant circuit is constructed by connecting multiple indoor units, and an electric expansion valve is installed 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 such that the connection is made using a built-in bypass circuit, even under low outdoor temperature conditions such as when operating an air conditioner in the winter, there is no imbalance between the indoor and outdoor functional capacities as when one indoor unit is operated. The imbalance is resolved by lowering the condensing capacity, making it possible to perform cooling operations that always maintain a proper operating pressure state throughout the year, regardless of the number of indoor units in operation.

BRIEF DESCRIPTION OF THE 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 (fill heat exchanger, 5...outdoor (llII expansion valve, 7a, 7b, 7c) ad...indoor unit, aa, sb, sc, sd...
...Indoor expansion valve, 9a, 9b, 9c, 9d...
... Indoor heat exchanger, 13 ... Refrigerant circuit, 1
4...Outdoor unit, 15...Electric expansion valve,
16...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 bypass circuit connecting the four-way valve and the outdoor heat exchanger and between the outdoor expansion valve and the indoor expansion valve is provided, and an electric expansion valve is provided in the middle of the bypass circuit. Multi-room air conditioner.