JPH05172388A - Air conditioner - Google Patents

Abstract

PURPOSE:To obtain an air conditioner, in which no dew no dew adheres on an indoor machine. CONSTITUTION:The valve opening of a motor control valve 8a continuously connected to an indoor heat exchanger is throttled in response to the ratio of the magnitude of load regarding the indoor heat exchanger 9a having small load in indoor heat exchangers under different load states by cooling operation, and the quantity of air of a corresponding indoor fan 55a is controlled so that the quantity of discharged refrigerant superheated in the indoor heat exchanger 9a reaches a set value on the basis of the difference of the detecting values of first and second refrigerant-temperature detecting sensors 52a, 53a mounted to the liquid line and gas line of the indoor heat exchanger 9a respectively. Consequently, when the quantity of the discharged refrigerant superheated is increased, the quantity of air of the indoor fan 55a is lowered, and the quantity of heat exchange is reduced and the quantity of the discharged refrigerant superheated is brought to the set value. Accordingly, even when rooms under different load states are air-conditioned, no dew adheres on an indoor machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a plurality of indoor exchangers.

[0002]

2. Description of the Related Art Conventionally, an indoor unit provided with an indoor heat exchanger is installed in each room for air conditioning of a plurality of rooms.
An air conditioner in which a plurality of indoor heat exchangers are connected to one compressor and an outdoor heat exchanger to form a refrigeration cycle and the refrigerant flow is switched to enable both cooling and heating operations is provided. is there. In such an air conditioner, the opening degree of a control valve provided in series with each indoor heat exchanger is adjusted according to the load state of each room to cope with the situation.

A conventional air conditioner having a plurality of indoor heat exchangers will be described below with reference to FIG. Figure 4
[Fig. 4] is a refrigeration cycle diagram.

In FIG. 4, the compressor 2 of the refrigeration cycle 1
Is connected to the discharge port 3 and the suction port 4 of the first and second connection ports of the four-way valve 5, and the third connection port of the four-way valve 5 is connected to one side connection port of the outdoor heat exchanger 6. Are connected.
Further, an electric expansion valve 7 formed so that the valve opening degree is adjusted and controlled is connected to the other side connection port of the outdoor heat exchanger 6, and the electric expansion valve 7 and the remaining fourth part of the four-way valve 5 are connected. The electric control valves 8a, 8b whose valve opening degree is adjustable and controllable according to the difference between the set room temperature and the room temperature are connected in series to the one side connection port on the electric expansion valve 7 side. The indoor heat exchangers 9a and 9b are connected so as to be provided in parallel. Then, by switching the four-way valve 5, the circulation direction of the refrigerant is changed, thereby enabling the cooling / heating operation.

Further, one end of each of the throttle mechanisms 10 and 11 is connected to the connection ports on both sides of the electric expansion valve 7, and one end of the common pipe 12 is connected to the other end.
The other end of 2 is connected to the suction port 4, and the saturation temperature detection circuit 13
Is configured. A saturation temperature sensor 14 is provided on the suction port 4 side of the common pipe 12 of the saturation temperature detection circuit 13. Further, a suction temperature sensor 15 for detecting the suction temperature of the refrigerant is provided in the refrigerant passage between the four-way valve 5 and the suction port 4 of the compressor 2. Then, the valve opening degree of the electric expansion valve 7 is adjusted and controlled according to the detection values of the saturation temperature sensor 14 and the suction temperature sensor 15.

On the other hand, the indoor heat exchangers 9a and 9b are arranged in the indoor units 16a and 16b so that the indoor heat exchangers 9a and 9b and the respective air passages intersect each other. The indoor fans 17a and 17b are provided, and room temperature sensors 18a and 18b for detecting the room temperature are provided.

When the cooling operation is performed with the above-described structure, the four-way valve 5 is switched as shown by the solid line, and the refrigerant flows in the direction of the arrow. And the indoor heat exchangers 9a, 9
b, the valve opening degree of the electric control valves 8a and 8b inserted in the liquid line of the refrigerant is adjusted by the room temperature set in the control device (not shown) and the room temperature of the installed room. The opening degree of the expansion valve 7 is also controlled by a controller (not shown) so that the superheat amount of the suction refrigerant of the compressor 2 becomes constant.

Then, for example, the cooling operation of the air conditioner is started with the room temperature of each room being the same, the set room temperature of the room A in which the indoor unit 15a is installed is high, and the set room B of the room B in which the indoor unit 15b is installed is set. When the room temperature is lowered, the following control is performed.

That is, since the set room temperature of the room B is lower than that of the room A, the room B having a larger difference between the room temperature and the set room temperature has a larger cooling load, and the room A having a smaller load is provided in the indoor unit 15a. The valve opening of the electric control valve 8a connected to the indoor heat exchanger 9a is reduced to a small degree, and in the room B, the indoor heat exchanger 9b provided in the indoor unit 15b.
The valve opening degree of the electric control valve 8b connected to the is controlled to be fully opened.

Further, the refrigerant flows through both indoor heat exchangers 9a and 9b, exits from each one-side connection port, is mixed, and flows to the suction port of the compressor 2 via the four-way valve 5, so that the compressor 2 is simultaneously operated.
The valve opening degree of the electric expansion valve 7 is controlled so that the superheat amount of the suction refrigerant is constant.

Then, in the finally stable state, the amount of the refrigerant flowing through the indoor heat exchanger 9a in the room A having a small load is small, so that all the refrigerant flows while flowing to the intermediate portion of the indoor heat exchanger 9a. It evaporates and indoor heat exchanger 9a
Since the amount of superheat of the discharged refrigerant becomes large and the amount of refrigerant flowing through the indoor heat exchanger 9b of the room B having a large load is large, the refrigerant does not evaporate entirely in the indoor heat exchanger 9b and the outlet portion However, it becomes a liquid back state in which the refrigerant liquid still remains.

When the amount of superheat of the refrigerant discharged from the indoor heat exchanger 9a becomes large as described above, the cooled air and the uncooled air are mixed in the indoor unit 15a provided with the indoor heat exchanger 9a. The dew adheres to the outlet of the indoor unit 15a to which the cooling air is sent by the indoor fan 17a, and in some cases, the dew may become water droplets and scatter in the room A.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the situation that dew may adhere to the indoor unit when the set room temperature is changed depending on the room as described above. Even if the load condition is different, such as the set room temperature is different depending on the room where the air conditioning is performed, dew does not adhere to the indoor unit and there is no risk of water droplets splashing indoors. To provide a harmony machine.

[0014]

The air conditioner of the present invention comprises:
A compressor, an expansion valve whose valve opening is controllable so that the superheat amount of the suction refrigerant of the compressor is a set predetermined value, and a low pressure side of this expansion valve are connected in parallel. A plurality of indoor heat exchangers, an indoor fan that is arranged so that these indoor heat exchangers and their respective air passages intersect with each other so that the air volume can be controlled, and the indoor heat exchangers are provided in correspondence with each other. A room temperature detecting means, a control valve which is provided between the one-side connection port of the indoor heat exchanger and the low pressure side of the expansion valve, and the valve opening of which is adjusted and controlled based on the detection signal of the room temperature detecting means,
The indoor heat exchanger is provided with first refrigerant temperature detecting means respectively provided on one side connection port side and second refrigerant temperature detecting means respectively provided on the other side connection port side of the indoor heat exchanger. For the indoor heat exchanger with the maximum difference between the set room temperature and the room temperature detected by the room temperature detection means, set the air volume of the corresponding indoor fan to a predetermined constant air volume and maximize the valve opening of the corresponding control valve. The first refrigerant corresponding to each of the indoor heat exchangers is controlled by adjusting the valve opening degree of the corresponding control valve according to the ratio of the difference between the set room temperature and the room temperature of the other indoor heat exchangers. The air flow rate of the corresponding indoor fan is set so that the superheat amount of the discharged refrigerant of each indoor heat exchanger obtained from the difference between the detection values of the temperature detection means and the second refrigerant temperature detection means becomes a set predetermined value. It is characterized by being controlled.

[0015]

In the air conditioner configured as described above, among the indoor heat exchangers having different load states during the cooling operation, the maximum load indoor heat exchanger is fully opened with the valve opening of the control valve connected in series. In addition, the air volume of the corresponding indoor fan is set to a predetermined constant air volume, and for indoor heat exchangers with a small load, the valve opening of the control valves connected in series is adjusted and set according to the ratio of the load magnitude, and The air volume of the indoor fan that corresponds to the superheat amount of the refrigerant discharged from the indoor heat exchanger, which is obtained from the difference between the detection values of the refrigerant temperature detection means provided on both sides of the heat exchanger. When the superheat amount of the refrigerant discharged from the indoor heat exchanger with a small load becomes large, the air volume of the corresponding indoor fan is reduced so that the heat exchange amount is reduced. Discharged refrigerant super Since so over preparative amount becomes the set value, when is the load condition and setting the room temperature is different to harmonize different room air is also, dew indoor unit does not adhere,
There is no possibility that water droplets may fly into the room.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner having a plurality of indoor heat exchangers, which is an embodiment of the present invention, will be described below with reference to FIGS. FIG. 1 is a refrigeration cycle diagram, FIG. 2 is a block diagram showing a control situation of the control device, and FIG. 3 is a flowchart. It should be noted that the same parts as those of the related art will be denoted by the same reference numerals and the description thereof will be omitted, and a configuration of the present invention different from the related art will be described.

In FIG. 1, the temperature of the refrigerant is detected in the respective refrigerant passages between the electric control valves 8a and 8b and the respective one-side connection ports of the indoor heat exchangers 9a and 9b constituting the refrigeration cycle 51. The first refrigerant temperature detecting sensors 52a, 52b are provided, and the second refrigerant temperature detecting sensor 5 for detecting the temperature of the refrigerant is also provided in the refrigerant flow path of each other side connection port.
3a and 53b are provided.

Further, the indoor heat exchangers 9a, 9b are provided in the indoor units 54a, 54b provided with the indoor heat exchangers 9a, 9b.
b and the indoor fans 55a and 55b arranged so that the respective air passages intersect with each other, and the room temperature sensor 18 for detecting the room temperature.
a and 18b are provided. In addition, the indoor fan 55a,
55b denotes the first refrigerant temperature detection sensor 52 during the cooling operation.
a, 52b and second refrigerant temperature detection sensors 53a, 53b
The number of revolutions is controlled and the amount of air is changed according to the difference in the detected values.

On the other hand, the control device 5 not shown in FIG.
As shown in FIG. 2, 6 is a signal input by the set room temperature input means 57a, 57b provided in each indoor unit 54a, 54b, the room temperature sensors 18a, 18b, and the first refrigerant temperature detection sensors 52a, 52b. , The second refrigerant temperature detection sensors 53a and 53b, the saturation temperature sensor 14, and the suction temperature sensor 15 are used as inputs, and arithmetic processing by a built-in microcomputer is performed to perform the operation frequency of the compressor 2 and the electric expansion. The valve openings of the valve 7 and the electric control valves 8a and 8b, and the rotation speeds of the indoor fans 55a and 55b are controlled.

When the cooling operation is performed with the above-described structure, the four-way valve 5 is switched as shown by the solid line, and the refrigerant flows in the direction of the arrow. Then, for example, the cooling operation of the air conditioner is started with the room temperature of each room being the same, the set room temperature of the room X in which the indoor unit 54a is installed is high, and the indoor unit 5
When the set room temperature of the room Y in which 4b is installed is lowered, the operation is performed under the following control.

That is, first, the set room temperature input means 57a,
57b and the room temperature sensors 18a, 1
The loads of the rooms X and Y are calculated from the room temperature signals of the rooms X and Y detected by 8b, and the loads of the rooms X and Y are compared. In this case, since the set room temperature of the room Y is lower than that of the room X, it is determined that the room Y having a large difference between the room temperature and the set room temperature has a larger cooling load.

In the room Y where the load is large, the valve opening of the electric control valve 8b, which is connected to the indoor heat exchanger 9b provided in the indoor unit 54b, is controlled to the fully open state, and the load is small. In the room X, the valve opening degree of the electric control valve 8a connected to the indoor heat exchanger 9a provided in the indoor unit 54a is narrowed down according to the load ratio.
Thereby, the flow rate distribution of the refrigerant is performed according to the load ratio.

Next, the total load is calculated from the total load of both rooms X and Y, and the operating frequency of the compressor 2 is determined according to the amount of the total load.

In the room Y where the load is large, the indoor fan 55b arranged in the indoor heat exchanger 9b is controlled to a constant rotation speed so as to obtain a predetermined air volume.

Regarding the room X having a small load, the first refrigerant temperature detecting sensor 52a which is provided in each refrigerant passage connected to the connection port of the indoor heat exchanger 9a and measures the refrigerant temperature of the liquid line. The difference between the detected value and the detected value of the second refrigerant temperature detection sensor 53a that measures the refrigerant temperature of the gas line is calculated, and as a result, the indoor heat exchanger 9
The superheat amount of the discharged refrigerant of a is calculated. Then, the calculated superheat amount of the discharged refrigerant is compared with the preset set value of the superheat amount, and the air flow rate of the indoor fan 55a arranged in the indoor heat exchanger 9a is determined so that both values match. The rotation speed of the indoor fan 55a is controlled so that the air volume can be obtained.

Further, regarding the electric expansion valve 7, the difference between the detection values of the saturation temperature sensor 14 and the suction temperature sensor 15 provided in the saturation temperature detection circuit 13 is calculated, and the difference is detected. The superheat amount of the suction refrigerant of the machine 2 is calculated. Then, the calculated superheat amount of the suction refrigerant and the preset set value of the superheat amount are compared, and the valve opening degree of the electric expansion valve 7 is controlled so that both values match.

When the operation is continued, the amount of the refrigerant flowing through the indoor heat exchanger 9a in the room X having a small load is small, so that all the refrigerant evaporates while flowing to the intermediate portion of the indoor heat exchanger 9a, The amount of superheat of the refrigerant discharged from the heat exchanger 9a tends to become large, but if such a state is reached, the preset value of the amount of superheat deviates from the preset value. The rotation speed of the indoor fan 55a arranged in the air conditioner 9a is controlled to decrease, the air volume decreases, and the heat exchange amount in the indoor heat exchanger 9a decreases. Then, the superheat amount of the refrigerant discharged from the indoor heat exchanger 9a becomes small and becomes stable in accordance with the set value.

Therefore, the superheat amount of the refrigerant discharged from the indoor heat exchanger 9a does not become large, and when the conventional superheat amount is large, there is no problem such that dew adheres to the blowout port of the indoor unit, etc. The dew does not adhere to the indoor unit 54a provided with the exchanger 9a, and there is no fear that the dew will become water droplets and scatter into the room X where the air conditioning is performed. Can be realized.

In the above embodiment, the indoor units 54a and 54b installed in the two different rooms X and Y are described, but the invention is not limited to this.
Similarly for a large number of cases, the valve opening of the electric control valve corresponding to the indoor heat exchanger with the maximum load is fully opened,
The indoor fan is also set so as to have a predetermined air volume, and for the remaining plurality of indoor heat exchangers, the valve opening degree of the corresponding electric control valve is determined according to the load ratio of each of the indoor heat exchangers. The air volume of each indoor fan may be controlled so that the superheat amount of the discharged refrigerant matches the set value.
The present invention can be appropriately modified and implemented within the scope of the gist.

[0030]

As is apparent from the above description, according to the present invention, among the indoor heat exchangers having different load states during the cooling operation, the indoor heat exchanger with a small load is connected by the control valves connected in series. The valve opening is adjusted and set according to the load magnitude ratio, and based on the difference between the detection values of the refrigerant temperature detecting means provided at both connection ports of the indoor heat exchanger, the indoor heat exchanger By adjusting the air volume of the corresponding indoor fan so that the superheat amount of the discharged refrigerant reaches the set value, when air conditioning is performed in rooms with different load conditions such as different set room temperatures. Also, it is possible to provide a comfortable air conditioner in which dew does not adhere to the indoor unit and water drops are unlikely to be scattered in the room.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a control situation of a control device according to an embodiment of the present invention.

FIG. 3 is a flowchart of an embodiment of the present invention.

FIG. 4 is a refrigeration cycle diagram showing a conventional example.

[Explanation of symbols]

 2 ... Compressor 7 ... Electric expansion valve 8a, 8b ... Electric control valve 9a, 9b ... Indoor heat exchanger 18a, 18b ... Room temperature detection sensor 52a, 52b ... 1st refrigerant temperature detection sensor 53a, 53b ... 2nd refrigerant Temperature detection sensors 55a, 55b ... Indoor fan

Claims (1)

[Claims] 1. A compressor, an expansion valve whose valve opening is controllable so that a superheat amount of suction refrigerant of the compressor is a set predetermined value, and a low pressure side of the expansion valve. A plurality of indoor heat exchangers connected in parallel, an indoor fan arranged so that these indoor heat exchangers and their respective air passages intersect with each other so that the air volume can be controlled, and the indoor heat exchanger Room temperature detecting means provided corresponding to each, and the valve opening degree is adjusted and controlled based on the detection signal of the room temperature detecting means provided respectively between the one side connection port of the indoor heat exchanger and the low pressure side of the expansion valve. Control valve, a first refrigerant temperature detecting means provided on one side connection port side of the indoor heat exchanger, and a second refrigerant temperature detection means provided on the other side connection port side of the indoor heat exchanger. It is equipped with a temperature detecting means, and detects the set room temperature and the room temperature detecting means. For the indoor heat exchanger having the largest difference in room temperature, the air volume of the corresponding indoor fan is set to a predetermined constant air volume, and the valve opening of the corresponding control valve is controlled to be the maximum, and Regarding the indoor heat exchanger, the valve opening degree of the corresponding control valve is adjusted and set according to the ratio of the difference between the set room temperature and the room temperature, and the first refrigerant temperature corresponding to the indoor heat exchanger is set. The air volume of the corresponding indoor fan is adjusted so that the superheat amount of the refrigerant discharged from each indoor heat exchanger obtained from the difference between the detection values of the detection means and the second refrigerant temperature detection means becomes the set predetermined value. An air conditioner characterized by being controlled.