JPH05322349A - Air conditioner - Google Patents

Abstract

PURPOSE:To easily control a flow rate of refrigerant by a low-cost structure by providing an electronic expansion valve in an outdoor unit, providing a solenoid valve in a liquid tube to a heat exchanger and so constituting by closing the solenoid valve as not to circulate refrigerant to an indoor unit which is not operated. CONSTITUTION:An air conditioner has an outdoor unit A and two indoor units B, C to be connected via conduits to constitute a refrigerating cycle. In this case, at the time of, for example, room cooling, high pressure gas refrigerant discharged from a compressor 11 is fed to a heat source side heat exchanger 4 through a four-way switching valve 3, in which the refrigerant becomes high pressure liquid refrigerant. The liquid refrigerant becomes low pressure two- phase refrigerant through an electronic expansion valve 5. Further, the two-phase refrigerant is distributed by a plurality of solenoid valves 7a, 7b in response to capacities of the units B, C. Then, the two-phase refrigerant is fed to a plurality of user side heat exchangers 6a, 6b to be heat exchanged with the air in a room to become low pressure gas refrigerant and to cool the room.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of an indoor unit of an air conditioner.

[0002]

2. Description of the Related Art An air conditioner that uses an expansion mechanism for an indoor unit uses an electric expansion valve for the expansion mechanism, as described in, for example, Japanese Patent Laid-Open No. 63-96438, and the suction temperature and the indoor heat This is a method of controlling the electric expansion valve based on the deviation from the refrigerant evaporation temperature or the refrigerant condensation temperature of the exchanger. However, although the electric expansion valve can control the opening degree widely, it is expensive, and when it is not necessary to finely adjust the refrigerant flow rate according to the load, a fixed opening degree can often be substituted.

On the other hand, there is a method of using a capillary for the expansion mechanism having a fixed opening. In this case, the capillaries are inexpensive, but when operating the units individually, if there is a stopped unit, in the case of the capillaries, the refrigerant circulates also in the stop unit, so the flow rate control of the refrigerant to the operating unit is not possible. There is a problem of being difficult.

[0004]

As described above, there are the following problems in the prior art of the expansion mechanism for the indoor unit heat exchange side piping. That is, (1) When an expansion valve is used for the expansion mechanism, the expansion valve is expensive, and there is a problem in terms of price, and cost performance is poor when fine opening adjustment is unnecessary.

(2) If a capillary with a fixed opening is used for the expansion mechanism, the refrigerant circulates through the capillaries of the units that are stopped when the units are individually operated, which makes it difficult to control the flow rate of the operating unit. ..

An object of the present invention is to provide an inexpensive expansion mechanism and a mechanism in which a refrigerant does not flow to a stopped unit.

[0007]

In order to achieve the above object, the present invention firstly provides an outdoor expansion unit with an electronic expansion valve, and each indoor unit is provided with a solenoid valve with a fixed opening having a different diameter according to its capacity. The opening control of the expansion mechanism that affects the entire refrigeration cycle is performed by the electronic expansion valve of the outdoor unit, and the electromagnetic valve of the indoor unit is mainly used for controlling the flow rate of the refrigerant. When the solenoid valve is closed, the refrigerant does not flow into the indoor unit, and when it is opened, the amount of refrigerant corresponding to the capacity flows and the air-conditioned room can be air-conditioned. Also, when performing heating operation, refrigerant and refrigerating machine oil accumulate in the heat exchanger of the stopped unit,
Since the amount of lubricating oil in the compressor is insufficient, it is necessary to control the solenoid valve to be opened for a predetermined period of time after the solenoid valve has been closed for a certain period of time.

[0008]

When the cooling operation is performed, each device of the present invention operates as follows.

The refrigerant compressed by the compressor passes through the outdoor heat exchanger and is liquefied. Then, the pressure is reduced by the electronic expansion valve of the outdoor unit. The depressurized refrigerant is distributed to each of the plurality of indoor units by an appropriate amount by a solenoid valve having a fixed opening of the indoor unit (a solenoid valve having a different diameter is used depending on the capacity of the indoor unit).

As described above, the electronic expansion valve of the outdoor unit controls the opening of the expansion mechanism of the entire refrigeration cycle, and the solenoid valve of the indoor unit opens and closes the solenoid valve to distribute and stop the refrigerant. The main purpose is to prevent the inflow of refrigerant.

[0011]

EXAMPLE An example of the present invention will be described with reference to FIG.

As shown in FIG. 1, the air conditioner of this embodiment is
It is composed of an outdoor unit A and two indoor units B and C, and these units are connected by a pipeline to form a refrigeration cycle.

The outdoor unit A comprises a compressor 1, an accumulator 2, a four-way switching valve 3, a heat source side heat exchanger 4, and an electronic expansion valve 5. On the other hand, the indoor units B and C are respectively provided with use side heat exchangers 6a and 6b and electromagnetic valves 7a and 7b. The indoor units B and C have different capacities, and the total capacity of these indoor units B and C is equivalent to the capacity of the outdoor unit A. Pipe connections 8a, 8b, 9a, 9b are provided in the pipes connecting the units, the gas-side and liquid-side outdoor units, and the indoor units.

The case of performing the cooling operation will be described below. The high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 3 and flows into the heat source side heat exchanger 4. In the heat exchanger 4, this refrigerant radiates heat and is condensed and liquefied to become a high-pressure liquid refrigerant.
By passing through the electronic expansion valve 5, the high-pressure liquid refrigerant becomes a low-pressure two-phase refrigerant. Regarding the solenoid valves 7a and 7b, the size of the diameter of the solenoid valve is selected according to the capacity of the indoor unit, so that the low-pressure two-phase refrigerant that has passed through the electronic expansion valve 5 is distributed according to the capacity of the indoor unit. To In this way, the two-phase refrigerant is properly distributed and the two-phase refrigerant is used by the use side heat exchangers 6a and 6b.
Then, it exchanges heat with the indoor air and evaporates to become a low-pressure gas refrigerant, and at the same time, performs an indoor cooling action. Then, the low-pressure gas refrigerant passes through the four-way switching valve 4 and the accumulator 2 and returns to the compressor 1. The above cycle is repeated to cool the air-conditioned room.

The solenoid valves 7a and 7b are provided for proper distribution of the refrigerant, and the expansion mechanism that controls the refrigeration cycle is controlled by using the electronic expansion valve in the outdoor unit.

When the indoor unit C is not operated, the solenoid valve 7b is closed to prevent the refrigerant from flowing into the indoor unit. Solenoid valve 7 during heating operation
By closing b, the liquid refrigerant stays in the utilization side heat exchanger. Since the refrigerating machine oil is mixed in the liquid refrigerant, if the electromagnetic valve 7b is left closed while the amount of lubricating oil in the compressor is insufficient, after a predetermined time, the electromagnetic valve 7b is opened and the liquid refrigerant is returned. , Control to close the solenoid valve again.

According to this embodiment, an inexpensive solenoid valve can be used as the expansion mechanism of the indoor unit, and the cost can be reduced. In addition, closing the solenoid valve has the effect of ensuring that the refrigerant does not flow into the stopped unit, and by opening and closing the solenoid valve during heating operation, the refrigerant does not stay in the indoor heat exchanger for a long time, and the oil sliding The amount can be secured.

[0018]

According to the present invention, it is possible to provide an inexpensive expansion mechanism and a mechanism in which the refrigerant does not flow to the stopped unit.

[Brief description of drawings]

FIG. 1 is a cycle system diagram of an embodiment of the present invention.

[Explanation of symbols]

1 ... Compressor, 2 ... Accumulator, 3 ... Heat source side heat exchanger, 4 ... Four-way valve, 5 ... Outdoor electronic expansion valve, 6A, 6B ...
Utilization side heat exchanger, 7A, 7B ... Indoor solenoid valve, 8A, 8
B, 9A, 9B ... Piping connection.

Claims (1)

[Claims] 1. An air conditioner having one or a plurality of indoor units and one outdoor unit, wherein the outdoor unit has an electronic expansion valve whose opening can be controlled, and the heat exchanger is provided inside the outdoor unit. An electromagnetic valve is provided in the liquid side pipe leading to, a unit operating in each of the indoor units is used as an expansion mechanism with a fixed opening by opening the electromagnetic valve, and a unit that is not in operation closes the electromagnetic valve, An air conditioner characterized by not circulating a refrigerant.