JP2000329389A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration cycle air conditioner in which the suppercooling set values of two indoor units can be set individually and arbitrarily for heating operation and the supply air temperatures can be controlled arbitrarily. SOLUTION: Two indoor heat exchangers 7A, 7B are coupled sequentially with a compressor 3, a four-way valve 4, an outdoor heat exchanger 5 and branch pipes 6a1, 6b1 for branching two indoor units 2A, 2B through expansion valves 6a, 6b. In case of cooling operation, outlet side of one indoor heat exchanger 7A is coupled to the suction side of the compressor 3 through the four-way valve 4 and the other indoor heat exchanger 7B is coupled to the delivery side of the compressor 3 through an on/off valve 8 to establish a refrigeration cycle. In case of heating operation, the on/off valve 8 is opened and the opening of each expansion valve 6a, 6b is controlled depending on the difference between the total sum of the degree of supercooling of the indoor units and the degree of superheating of the outdoor units and preset total sums.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner in which two indoor units are connected to one outdoor unit. More specifically, the present invention relates to a method of separately setting a subcooling degree of each indoor unit during a heating operation. The present invention relates to a refrigeration cycle that can freely set the air temperature and control the blow-out air temperature.

[0002]

2. Description of the Related Art A conventional air conditioner is, for example, as shown in FIG. In the figure, 1 is an outdoor unit having a compressor 3, a four-way valve 4, an outdoor heat exchanger 5, etc., 2A 'and 2
B 'is an indoor unit installed in the same room.
A 'is provided near the ceiling of the room with the indoor heat exchanger 7A', the other indoor unit 2B 'is installed near the floor of the room with the indoor heat exchanger 7B', and the indoor unit 2A 'is the same as before. The indoor unit 2B 'is operated for cooling and heating, and the indoor unit 2B' is configured to be able to operate simultaneously or arbitrarily with the indoor unit 2A for step heating during heating.

[0003] The compressor 3, the four-way valve 4, the outdoor heat exchanger 5
And branch pipes 6a1 and 6b1 for branching or joining the refrigerant to the two indoor units 2A 'and 2B', respectively, via expansion valves 6a 'and 6b' to the two indoor heat exchangers 7A 'and 7B'. The two indoor heat exchangers 7A 'and 7B' are joined at the outlet side during cooling, and connected to the suction side of the compressor 3 through the four-way valve 4 to form a refrigeration cycle. .

An outdoor heat exchange temperature sensor 5a and an indoor heat exchange temperature sensor 7a1 ', 7b1' for detecting the heat exchanger temperature are provided to the outdoor heat exchanger 5 and the two indoor heat exchangers 7A ', 7B', respectively. An outdoor outlet temperature sensor 5b and an indoor outlet temperature sensor for detecting the refrigerant temperature at the heat exchanger outlet at the refrigerant outlet side during heating of the outdoor heat exchanger 5 and the two indoor heat exchangers 7A 'and 7B'. 7a2 'and 7b2' are provided.

[0005] In the above configuration, the degree of subcooling of each indoor unit (difference between the temperature of the indoor heat exchanger and the temperature of the outlet of the heat exchanger) is made constant to control the flow of the refrigerant during the heating operation, and an appropriate flow is divided. Is secured. However, since the respective degrees of supercooling are set to be the same, the temperature of the blown air of both indoor units becomes substantially the same, and there is a problem that it is not possible to increase the temperature of the blown air particularly for step heating.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the set values of the degree of supercooling of each of two indoor units are individually and freely set at the time of a heating operation, so that the temperature of the blown air can be freely set. It is an object of the present invention to provide a refrigeration cycle air conditioner that can be controlled at a high speed.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises an outdoor unit having a compressor, a four-way valve and an outdoor heat exchanger, and two indoor units having an indoor heat exchanger. In the air conditioner, the two indoor heat exchangers are connected in parallel to the outdoor heat exchangers via expansion valves to the respective branch pipes, and the outlet side of one of the indoor heat exchangers at the time of cooling is connected to the outdoor heat exchanger. Through a four-way valve, connected to the suction side of the compressor, the other indoor heat exchanger is connected to the discharge side of the compressor via an on-off valve to form a refrigeration cycle, the outdoor heat exchanger and the An outdoor heat exchange temperature sensor and an indoor heat exchange temperature sensor for detecting a heat exchanger temperature in two indoor heat exchangers are provided, respectively, and the refrigerant outlet side of the outdoor heat exchanger and the two indoor heat exchangers during heating. At the outlet of the heat exchanger Detecting, providing an outdoor exit temperature sensor and an indoor exit sensor, respectively, during heating operation, while opening the on-off valve, each heat exchanger temperature detected by the indoor heat exchange temperature sensors of the two indoor heat exchangers, The degree of supercooling due to the temperature difference between each of the heat exchanger outlet temperatures detected by the indoor outlet temperature sensor, the outdoor heat exchanger temperature detected by the outdoor heat exchange temperature sensor, and the heat detected by the outdoor outlet temperature sensor The degree of superheat due to the temperature difference from the exchanger outlet temperature is calculated, and the valve opening degree of the expansion valve is determined in accordance with the difference between the sum of the degree of supercooling and the degree of superheat, and a preset value of each sum. Are respectively controlled.

Further, the two indoor heat exchangers are installed in the same room, one indoor heat exchanger side indoor unit is installed near the ceiling, and the other indoor heat exchanger is installed near the floor. It has become.

When only one of the indoor units performs the heating operation, the opening degree of the expansion valve on the other indoor unit side is controlled to a half-open fixed state.

In the cooling operation, the on-off valve is closed and the expansion valve on the other indoor unit side is fully closed.
The expansion valve on the one indoor unit side, the heat exchanger temperature detected by the indoor heat exchange temperature sensor of the one indoor heat exchanger or the heat exchanger outlet temperature detected by the indoor outlet temperature sensor, and the outdoor outlet The valve opening is controlled in accordance with a difference between a degree of superheat due to a temperature difference from the outdoor heat exchanger temperature detected by the temperature sensor and a preset value of the degree of superheat.

The outdoor outlet temperature sensor is provided near the suction pipe of the compressor.

Further, the outdoor heat exchange temperature sensor and the indoor heat exchange sensor are configured to detect a temperature of a refrigerant substantially in the middle of a heat exchange path of each heat exchanger.

[0013] Further, a solenoid valve is used as the on-off valve.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as examples. 1 and 2, 1 is an outdoor unit having a compressor 3, a four-way valve 4, an outdoor heat exchanger 5, etc., 2A and 2B are indoor units installed in the same room, and one indoor unit 2A is an indoor unit. The indoor unit 2B is provided with a heat exchanger 7A and is installed near the ceiling of the room, and the other indoor unit 2B is installed near the floor of the room and provided with the indoor heat exchanger 7B.
Is operated for cooling and heating as in the past, and the indoor unit
2B is configured to be able to operate at the same time as the indoor unit 2A or arbitrarily for heating the feet during heating.

The compressor 3, the four-way valve 4, the outdoor heat exchanger 5
And branch pipes 6a1 and 6b1 for splitting or joining the refrigerant to the two indoor units 2A and 2B, respectively, are connected to the two indoor heat exchangers 7A and 7B via expansion valves 6a and 6b, respectively. The outlet side of the heat exchanger 7A at the time of cooling is connected to the suction side 3a of the compressor 3 through the four-way valve 4 and the other indoor heat exchanger 7B is compressed through the on-off valve 8 comprising an electromagnetic valve. The refrigeration cycle is formed by connecting to the discharge side 3b of the machine 3.

The outdoor heat exchanger 5 and the two indoor heat exchangers 7A and 7B are provided with an outdoor heat exchange temperature sensor 5a and indoor heat exchange temperature sensors 7a1 and 7b1, respectively, for detecting a heat exchanger temperature. An outdoor outlet temperature sensor 5b and indoor outlet temperature sensors 7a2 and 7b2 for detecting the refrigerant temperature at the heat exchanger outlet are provided on the refrigerant outlet side during heating of the heat exchanger 5 and the two indoor heat exchangers 7A and 7B, respectively. Configuration.

In the above configuration, during the heating operation, the respective heat exchanger temperatures T7a1, T7b1 detected by the indoor heat exchange temperature sensors 7a1, 7b1 of the two indoor heat exchangers 7A, 7B and the indoor outlet temperature sensor 7b1 , 7b2 detect the temperature difference (T7a1-T7a2) from the respective heat exchanger outlet temperatures T7a2, T7b2.
= UA) and (T7b1-T7b2 = UB) can be captured as the degree of supercooling in the respective indoor heat exchangers 7A and 7B.

Further, during the heating operation, the heat exchanger temperature T5a detected by the outdoor heat exchange temperature sensor 5a of the outdoor heat exchanger 5;
The temperature difference (T5a−T5b = DA) from the heat exchanger outlet temperature T5b detected by the outdoor outlet temperature sensor 5b can be captured as the degree of superheat in the outdoor heat exchanger 5.

When the two indoor heat exchangers 7A and 7B are simultaneously operated for heating, the on-off valve 8 is opened and the degree of superheat DA
(DA + UA = PA), (DA + UA = PA) and (DA + U) of the supercooling degrees UA and UB of the two indoor heat exchangers 7A and 7B.
B = PB) are the expansion valve control values PA, PB of the indoor heat exchangers 7A, 7B, respectively, and the respective expansion valves 6a, 6b are determined according to the difference between the control values PA and PB.
By controlling the valve opening degree, the air temperature required for each of the indoor units 2A and 2B can be freely set and adjusted.

When only one of the indoor units 2A and 2B is operated for heating, the one indoor unit 2A is connected to the superheat degree DA.
By controlling the degree of superheat in accordance with the difference between the degree of superheat and the preset degree of superheat, the degree of opening of the expansion valve 6a is controlled, and the degree of opening of the expansion valve 6b of the other indoor unit 2B. Is controlled to a half-open fixed state.

During the cooling operation, the on-off valve 8 is closed, the expansion valve 2B on the other indoor unit 2B is fully closed, and the expansion valve 6a on the one indoor unit 2A is closed. The heat exchanger temperature T7a1 detected by the indoor heat exchange temperature sensor 7a1 of one indoor heat exchanger 2A or the indoor exit temperature sensor 7a2
The temperature difference (T7a1-5b) between the heat exchanger outlet temperature T7a2 detected by the above and the outdoor heat exchanger temperature T5b detected by the outdoor outlet temperature sensor 5b, or the degree of superheat due to (T7a2-5b), is set in advance. The valve opening is controlled in accordance with the difference between the superheat degree and the set value.

Further, by providing the outdoor outlet temperature sensor 5b in the vicinity of the suction pipe 3a of the compressor 3, a more accurate degree of superheat can be detected.

Further, since the indoor heat exchange temperature sensor 7a1 and the indoor heat exchange sensor 7b1 are configured to detect the temperature of the refrigerant substantially in the middle of the heat exchange paths of the heat exchangers 7A and 7B, more accurate supercooling can be achieved. Degree can be detected.

In the above description, the average temperature of the indoor heat exchanger can be increased and the blowout temperature can be increased by setting the degree of supercooling of the indoor unit requiring a high blowout air temperature to be small. Conversely, an indoor unit that does not require a very high blowout temperature is an air conditioner that can lower the average temperature of the indoor heat exchanger and lower the blowout temperature by setting the degree of supercooling to be large.

[0025]

As described above, according to the present invention, when the indoor heat exchangers of the two indoor units installed near the ceiling and near the feet of the floor are simultaneously heated, the superheat degree and the two indoor heat The sum of the degree of supercooling of each exchanger and the expansion valve control value of each indoor heat exchanger is used as the expansion valve control value of each indoor heat exchanger. By adopting a configuration in which the degree is controlled, an air conditioner that can freely set and adjust the blown air temperature required for each indoor unit is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of an air conditioner showing one embodiment of the present invention.

FIG. 2 is a diagram showing an operation relationship of an on-off valve and an expansion valve of a refrigeration cycle according to the present invention.

FIG. 3 is a block diagram of an air conditioner showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 outdoor unit 2A, 2B indoor unit 3 compressor 4 four-way valve 5 outdoor heat exchanger 5a outdoor heat exchange temperature sensor 5b outdoor outlet temperature sensor 6a, 6b expansion valve 6a1,6b1 branch pipe 7A, 7B indoor heat exchanger 7a1,7b1 Indoor heat exchange temperature sensor 7a2, 7b2 Indoor exit temperature sensor 8 On-off valve (solenoid valve)

Claims (7)

[Claims] 1. An air conditioner comprising an outdoor unit having a compressor, a four-way valve and an outdoor heat exchanger, and two indoor units having an indoor heat exchanger, wherein each of the two indoor heat exchangers is connected to a branch pipe. Connected to the outdoor heat exchanger in parallel via an expansion valve, and the outlet side of one indoor heat exchanger during cooling is connected to the suction side of the compressor through the four-way valve, and the other indoor heat exchanger An outdoor heat exchange temperature sensor, which is connected to the discharge side of the compressor via an on-off valve to form a refrigeration cycle, and detects a heat exchanger temperature in the outdoor heat exchanger and the two indoor heat exchangers; An indoor heat exchange temperature sensor and an indoor air outlet temperature sensor for detecting a refrigerant temperature at an outlet of the heat exchanger at a refrigerant outlet side of the outdoor heat exchanger and the two indoor heat exchangers at the time of heating; Provided respectively During the heating operation, the on-off valve is opened, the respective heat exchanger temperatures detected by the indoor heat exchange temperature sensors of the two indoor heat exchangers, and the respective heat exchanger outlet temperatures detected by the indoor outlet temperature sensor. And the degree of supercooling due to the temperature difference between
Calculate the degree of superheat due to the temperature difference between the outdoor heat exchanger temperature detected by the outdoor heat exchange temperature sensor and the heat exchanger outlet temperature detected by the outdoor outlet temperature sensor, and sum the supercooling degree and the superheat degree. An air conditioner characterized by controlling the valve opening of each of the expansion valves according to a difference between the predetermined value and a preset value of the total sum. 2. The two indoor heat exchangers are installed in the same room, one indoor heat exchanger side indoor unit is installed near a ceiling, and the other indoor unit is installed near a floor. The air conditioner according to claim 1, wherein: 3. When only one of the indoor units performs the heating operation, the valve opening of the expansion valve on the other indoor unit side is controlled to a half-open fixed state. 2. The air conditioner according to 2. 4. During cooling operation, the on-off valve is closed, the expansion valve on the other indoor unit is fully closed, and the expansion valve on the one indoor unit is connected to the one indoor heat exchanger. The heat exchanger temperature detected by the indoor heat exchange temperature sensor or the heat exchanger outlet temperature detected by the indoor outlet temperature sensor, and the degree of superheat due to the temperature difference between the outdoor heat exchanger temperature detected by the outdoor outlet temperature sensor, The air conditioner according to claim 1 or 2, wherein the valve opening is controlled in accordance with a difference from a preset superheat degree. 5. The air conditioner according to claim 1, wherein the outdoor outlet temperature sensor is provided near a suction pipe of the compressor. 6. The air conditioner according to claim 1, wherein the outdoor heat exchange temperature sensor and the indoor heat exchange sensor detect a refrigerant temperature substantially in the middle of a heat exchange path of each heat exchanger. 7. The air conditioner according to claim 1, wherein an electromagnetic valve is used as the on-off valve.