JPH0320666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a multi-chamber air conditioner, more specifically, a multi-chamber air conditioner, specifically, a multi-chamber air conditioner equipped with a compressor, a four-way switching valve, and a heat source side heat exchanger.
The present invention relates to a multi-room air conditioner that is composed of one outdoor unit and a plurality of indoor units each equipped with a user-side heat exchanger and a fan, and that can be heated and cooled by switching the four-way switching valve.

(Prior Art) Generally, in a multi-room air conditioner in which multiple indoor units are connected to one outdoor unit as described above, the indoor unit is connected to the liquid side main pipe and the gas side main pipe that are piped to the outdoor unit. A plurality of liquid side branch pipes and gas side branch pipes corresponding to the number of units are connected, and a solenoid valve is installed in each of these branch pipes, and these solenoid valves are turned on and off according to the operation or stoppage of the indoor unit. It is usually configured as follows.

However, solenoid valves operate on and off, and are designed to open fully when turned on, so the indoor unit is equipped with an expansion mechanism for cooling and a check valve that bypasses the expansion mechanism. In addition, the outdoor unit must be provided with a heating expansion mechanism and a check valve that bypasses the expansion mechanism.
In addition, it is necessary to install a bypass circuit on the indoor unit side when the indoor unit is inactive during heating to drain the refrigerant that accumulates due to leakage from the solenoid valve of the gas side branch pipe to the low pressure side, making the refrigeration circuit complicated and increasing costs. There was a problem.

In response to this problem, a method using a thermoelectric expansion valve instead of the electromagnetic valve provided on the liquid side branch pipe has been proposed, as can be seen in, for example, Japanese Patent Laid-Open No. 56-49856.

To briefly explain this conventional example, as shown in FIG.
In a multi-room air conditioner in which a plurality of indoor units B each equipped with a user-side heat exchanger 54 and a fan 55 are connected via a plurality of connecting pipes C, from the liquid-side main pipe 56 of the outdoor unit A A thermoelectric expansion valve 58 is provided in each of the plurality of branched liquid side branch pipes 57, and a solenoid valve 61 is provided in each of the plurality of gas side branched pipes 60 branched from the gas side main pipe 59.

In addition, in FIG. 13, 62 is the liquid side main pipe 5.
6 is a first liquid receiver installed in each of the liquid side branch pipes 57, and 63 is a second liquid receiver installed in each of the liquid side branch pipes 57, in which the first liquid receiver 62 is used during cooling, and the second liquid receiver is used during heating. After the liquid refrigerant is received by the liquid container 63, it passes through the expansion valve 58.

(Problems to be Solved by the Invention) However, the expansion valve 58 uses a bimetal and an electric heater that heats the bimetal, and the valve opening degree is adjusted by controlling the amount of electricity supplied to the electric heater. It is designed so that it can be used in common as an expansion mechanism for cooling and heating, so there is no need to provide separate expansion mechanisms for cooling and heating, and the refrigeration circuit can be made that much simpler. However, since the expansion valve 58 corresponding to the indoor unit that is inactive is configured to be fully closed during cooling and fully open during heating, it is necessary to install a solenoid valve 61 in the gas side branch pipe 60. In addition, since the expansion valve 58 is commonly used as an expansion mechanism during heating and cooling, not only the first liquid receiver 62 is installed in the liquid side main pipe 56, but also the liquid side branch pipe 57 is equipped with the first liquid receiver 62. It is necessary to install the second liquid receiver 63 for each liquid side branch pipe 57, and as a result, a significant reduction in the number of parts cannot be expected compared to the general conventional example described above. The problem of the complexity of piping work has not yet been fully resolved.

Moreover, the expansion valve 58 only controls the degree of superheating during cooling and heating, and cannot control the degree of subcooling.Especially during heating, the expansion valve 58 controls the degree of superheating of the heat source side heat exchanger 53 of the outdoor unit A. Since the degree of superheating of the low-pressure gas refrigerant on the outlet side is controlled, the amount of refrigerant cannot be properly distributed to each indoor unit B. However, there is no description of a specific configuration for properly distributing refrigerant to each indoor unit B.

The object of the first invention (main invention) as set forth in claim 1 is to prevent liquid from accumulating in an indoor unit that is inactive without using a solenoid valve in the gas side branch pipe, and to prevent liquid from forming in the liquid side branch pipe. During cooling, the first motorized valve installed in the indoor unit controls the degree of superheating of the low-pressure gas refrigerant at the outlet side of the user-side heat exchanger installed in the indoor unit during cooling, and during heating, controls the degree of superheating of the low-pressure gas refrigerant at the outlet side of the user-side heat exchanger installed in the indoor unit. The degree of supercooling of the high-pressure liquid refrigerant at the outlet side of the exchanger can be controlled, and the degree of superheating at the heat source side of the outdoor unit and the outlet side of the heat exchanger can also be appropriately controlled. The point is to enable proper refrigerant distribution to the units.

Further, the object of the second invention as set forth in claim 2 is to further adjust the valve opening degree of the first electric valve provided in the liquid side branch pipe in correspondence with the indoor unit in operation. Adjustment is made by comparing the average temperature of the flowing high-pressure liquid refrigerant with the temperature of each high-pressure liquid refrigerant flowing through the liquid side branch pipes, thereby making it possible to further reduce the uneven flow of the refrigerant flowing to the indoor unit operating during heating.

In addition to the object of the first invention, the object of the third invention recited in claim 3 is to further correct the valve opening degree of the electric valve corresponding to the indoor unit that is inactive. The purpose of this invention is to more reliably prevent liquid accumulation in the indoor unit.

Furthermore, an object of the fourth invention described in claim 4 is, in addition to the object of the first invention, to also appropriately control the degree of subcooling on the heat source side heat exchanger outlet side of the outdoor unit during cooling. In this way, the heating and cooling capacity can be improved and the EER can be improved.

(Means for Solving the Problem) The configuration of the first invention is a multi-room air conditioner that includes a plurality of liquid side branch pipes 5 and a gas side branch pipe 7, and is capable of heating and cooling by switching the four-way switching valve 2. In,
Each of the liquid side branch pipes 5 is provided with a first motor-operated valve EV ₁ to EV ₃ whose valve opening degree can be adjusted from fully closed to an arbitrary opening degree, and the liquid side main pipe 4 is provided with a first electric valve EV 1 to EV 3 that can adjust the valve opening degree from fully closed to an arbitrary opening degree. A superheat degree control valve EV ₄ that controls the superheat degree of the low-pressure gas refrigerant on the outlet side of the heat exchanger 3 during heating is interposed, and the first electric valves EV ₁ to EV ₃ and the superheat degree control valve EV ₄ are connected to each other. One liquid receiver 10 is interposed in the liquid side main pipe 4 between , the first electric valve corresponding to the operating indoor unit B.
means for adjusting EV ₁ to _{EV 3} to a constant opening degree corresponding to the number of operating indoor units B; and the first electric valve corresponding to the indoor unit B that is inactive during cooling.
Fully close EV ₁ to EV ₃ , stop the fan 9 of the indoor unit B that is inactive during heating, and close the first electric valves EV 1 to EV ₃ corresponding to the indoor unit B that is inactive during heating.
The invention is characterized by comprising a means for controlling the EV ₃ to a small opening degree, and the configuration of the second invention is the configuration of the first invention described above, further comprising:
Based on the detection result of the operation detection means 22, the first electric valves EV ₁ to EV ₃ corresponding to the indoor units B operating at the start of operation are set to a certain valve opening degree depending on the number of indoor units B in operation. and means for adjusting the temperature to open for a certain period of time, and _means for detecting the temperature of the high-pressure liquid refrigerant on the outlet side of the user-side heat exchanger 8 in the operating indoor unit B during heating.
TH ₃ , means for calculating the average temperature of the high-pressure liquid refrigerant flowing through each liquid side branch pipe 5 from the detection results of the detection means TH ₁ to _{TH 3} , and means for detecting the average temperature and each liquid refrigerant temperature. Compare the detection results of TH ₁ to _{TH 3} and adjust the valve opening degrees of the first electric valves EV ₁ to _{EV 3} corresponding to the operating indoor unit B, and The present invention is characterized by providing means for controlling the temperature of the high-pressure liquid refrigerant on the outlet side of the heat exchanger 8 so as to bring it close to the average temperature.

Further, the configuration of the third invention includes the configuration of the first invention described above and the configuration of the second invention, and further includes:
The detection results detected by the high-pressure liquid refrigerant temperature detection means TH ₁ to _{TH 3} are compared with the average temperature, and the temperature of the high-pressure liquid refrigerant on the outlet side of the user-side heat exchanger 8 in the indoor unit B that is inactive is determined as above. When the temperature is lower than the average temperature, the first unit corresponding to the inactive indoor unit B
The present invention is characterized in that it includes means for correcting the valve opening degrees of the electric valves EV ₁ to _{EV 3} to the open side.

Furthermore, in the configuration of the fourth invention, in the configuration of the first invention described above, instead of the superheat degree control valve EV ₄ interposed in the liquid side main pipe 4, a superheat degree control valve EV 4 is provided on the outlet side of the heat source side heat exchanger 3 during cooling A second electrically operated valve EV ₄ that controls the degree of subcooling and also controls the degree of superheating on the outlet side during heating is interposed, and the first electrically operated valves EV ₁ to EV ₃ and the second electrically operated valve EV ₄ are connected to each other. This is characterized in that one liquid receiver 10 is interposed in the liquid side main pipe 4 between the two.

(Function) In the first invention, the first electric valves EV ₁ to _{EV 3} corresponding to the operating indoor units B are adjusted to a constant opening according to the number of operating indoor units B, and the indoor units are closed during cooling. The degree of superheating of the low-pressure gas refrigerant on the outlet side of each user-side heat exchanger 8 provided in
The degree of subcooling of the high-pressure liquid refrigerant at the outlet side of each unit is controlled, and no uneven flow occurs in the amount of refrigerant flowing to each indoor unit B that operates both for air conditioning and heating. Furthermore, the superheat degree control valve EV ₄ provided in the liquid side main pipe 4 can also control the superheat degree of the low pressure gas refrigerant at the outlet side of the heat source device heat exchanger 3 provided in the outdoor unit A during heating. The first unit corresponding to the indoor unit B that is inactive
The electric valves EV ₁ to _{EV 3} are fully closed during cooling and are controlled to a small opening during heating, so refrigerant does not accumulate in indoor unit B when it is not in use, not only during cooling but also during heating. be.

Further, in the second invention, at the start of operation, the opening degrees of the first electric valves EV ₁ to _{EV 3} are adjusted to a constant valve opening degree for a certain period of time according to the number of operating indoor units B, Similarly to the first invention, each indoor unit B operates for both cooling and heating by controlling the degree of superheating of the low-pressure gas refrigerant at the outlet side of each user-side heat exchanger during cooling, and controlling the degree of subcooling of the high-pressure liquid refrigerant during heating. After a certain period of time has elapsed, during heating, the average temperature of the high-pressure liquid refrigerant flowing from the operating indoor unit B through each liquid side branch pipe 5 and each liquid side branch pipe are 5 and the temperature of the high-pressure liquid refrigerant in step 5, and based on this comparison, the valve opening degrees of the first electric valves EV ₁ to EV ₃ corresponding to the operating indoor unit B are adjusted to adjust the temperature of each high-pressure liquid refrigerant. The temperature is brought close to the average temperature, the degree of supercooling controlled by the first electric valves EV ₁ to _{EV 3} during heating is made appropriate, and the uneven flow of the refrigerant flowing to each operating indoor unit B is further reduced.

In addition, during heating, the first electric valve EV ₁ ~
The EV ₃ performs the above-mentioned supercooling degree control, and the superheat degree control valve EV ₄ provided in the liquid side main pipe 4 performs superheat degree control. The effect of preventing liquid accumulation in B is the same as in the first invention.

Moreover, in the third invention, the effect of the second invention described above is obtained, and the indoor unit B
The valve opening degree of the first electric valves EV ₁ to EV ₃ corresponding to In comparison, if the temperature is lower than the average temperature, it is corrected to the open side so that it is slightly opened, thereby more reliably preventing the formation of a liquid pool in the indoor unit B that is inactive.

Furthermore, in the fourth invention, the second electric valve EV ₄ interposed in the liquid side main pipe 4 controls the degree of subcooling of the high pressure liquid refrigerant at the outlet side of the heat source side heat exchanger 3 during cooling, and controls the degree of subcooling of the high pressure liquid refrigerant at the outlet side of the heat source side heat exchanger 3 during cooling, and during heating. a first electric valve that controls the degree of superheating of the low-pressure gas refrigerant on the outlet side of the heat source side heat exchanger 3, and is interposed in the liquid side branch pipe 5;
By controlling the degree of superheating during cooling and the degree of subcooling during heating using EV ₁ to EV ₃ , it is possible to control the degree of supercooling of the high-pressure liquid refrigerant at the outlet side of the heat exchanger that acts as a condenser during both cooling and heating. This also makes it possible to control the degree of superheating of the low-pressure gas refrigerant on the outlet side of the heat exchanger acting as an evaporator.

In this application, the first electric valves EV ₁ to _{EV 3} corresponding to the indoor unit B that are inactive during heating are controlled to a small opening degree by setting a small opening degree in advance and forcing it to this small opening degree. In some cases, a means for detecting the temperature of the high-pressure liquid refrigerant on the outlet side of the user-side heat exchanger 8 during heating is used, and in other cases, the temperature is controlled based on the detection result by this means. Further, the first electric valve EV ₁ ~
The small opening degree of EV ₃ is such that it allows a refrigerant flow rate commensurate with the amount of liquid refrigerant that liquefies due to natural heat dissipation in the user-side heat exchanger 8 of indoor unit B, which is inactive by stopping the fan 9 during heating. That is to say.

(First Embodiment) What is shown in FIGS. 1 to 5 is an embodiment of the first invention, and the basic configuration of the refrigerant piping system is as follows:
As shown in FIG. 1, a compressor 1, a four-way switching valve 2, a heat source side heat exchanger 3, a liquid side main pipe 4, a plurality of liquid side branch pipes 5 branching from this liquid side main pipe 4, and a gas side main pipe 6
One outdoor unit A is equipped with a plurality of gas side branch pipes 7 branching from the gas side main pipe 6, a user side heat exchanger 8 and a fan 9, and the liquid is supplied via a plurality of connecting pipes C. It consists of a plurality of indoor units B connected in parallel between a side branch pipe 5 and a gas side branch pipe 7, and can be heated and cooled by switching the four-way switching valve 2.

What is shown in FIG. 1 is a multi-chamber air conditioner configured as described above, in which first motor-operated valves EV 1 _{to 1} are provided in each of the liquid side branch pipes 5 and can be adjusted from fully closed to any desired opening. EV ₃ are interposed respectively, and the heat source side heat exchanger 3 is installed in the liquid side main pipe 4.
A superheat degree control valve (hereinafter referred to as the second electric valve for convenience of explanation, and the reference numeral is given as a second electric valve for convenience of explanation) that controls the degree of superheat of the low-pressure gas refrigerant on the outlet side during heating.
Set EV to ₄ . ), the first electric valve EV ₁
One liquid receiver 10 is interposed in the liquid side main pipe 4 between EV ₃ and the second electric valve EV ₄ that controls the degree of superheat.

In addition, in FIG. 1, 11 is a dryer, 12, 1
Reference numeral 3 designates a closing valve installed in the liquid side main pipe 4 and the gas side main pipe 5, 14 an accumulator, and 15 a fan attached to the heat source side heat exchanger 3.

In the above configuration, the first motor-operated valves EV ₁ to _{EV 3} mainly use a pulse motor that rotates at a certain angle with one pulse, and the number of pulses selected by a controller to be described later is used to operate the first motor-operated valves EV 1 to EV 3 completely as shown in FIG. 2. The valve opening degree is arbitrarily adjusted from closed to fully open, and each of the first electric valves EV ₁ to 1 corresponds to the indoor unit B to be operated.
The valve opening degree of the EV ₃ depends on the number of operating indoor units B, and the number of pulses input to the motor is set to 160 pulses during cooling and 150 pulses during heating in one room operation.
Pulses, 120 pulses for cooling in 2-room operation, 100 pulses for heating, and 100 pulses for cooling in 3-room operation.
The pulse is changed to 70 pulses during heating, and the opening degree is adjusted to a certain degree according to the number of pulses.
Further, the opening degree of each of the first electric valves EV ₁ to _{EV 3} corresponding to the indoor unit B which is inactive is controlled to be fully closed during cooling and to a small opening during heating.

That is, the fan 9 in the indoor unit B that is inactive during heating is stopped, and the first electric valve
The small opening degree control of EV ₁ to _{EV 3} is such that the high pressure gas refrigerant flowing from the gas side branch pipe 7 is connected to the indoor unit B.
The opening degree is set to an extent that allows a refrigerant flow rate commensurate with the amount of liquid refrigerant that liquefies due to natural heat radiation in the user-side heat exchanger 8.

This small opening control mainly involves forcing the controller to control the opening as described above. For example, the number of input pulses to the pulse motor is set to 40 pulses, and The opening is controlled to a constant degree.

Further, as the superheat degree control valve that controls the degree of superheat of the low-pressure gas refrigerant during heating, an external pressure equalization type or an internal pressure equalization type expansion valve may be used, but in this case, the first electric valves EV ₁ to EV Similar to ₃ , the second motor-operated valve EV ₄ whose opening degree is controlled mainly by a pulse motor is used.

When this second electric valve EV ₄ is used, it may be fully opened during cooling and controlled to a preset constant opening during heating, but preferably, the four-way switching valve 2 and the inlet of the compressor 1 are connected to each other. A temperature sensor TH ₇ (hereinafter referred to as the seventh temperature sensor for convenience of explanation) for detecting the temperature (T ₇ ) of the low-pressure gas refrigerant is provided in the suction pipe 16 that connects the gas area of the liquid receiver 10. A detection circuit 17 is provided between the intake pipe 16 and the suction pipe 16, and an expansion mechanism 18 such as a capillary tube is connected to the detection circuit 17.
is interposed between the expansion mechanism 18 and the connection portion to the suction pipe 16, and a temperature detector THe (for convenience of explanation below, an eighth temperature The deviation value (E ₁ ) from the target superheat degree (SH) of the low-pressure gas refrigerant detected by the seventh and eighth temperature detectors TH ₇ and THe, that is, E ₁ =T ₇ −Te− Find SH, for example proportional control (P control) or PD control,
Alternatively, the second electric valve EV ₄ is controlled by PID control.

In addition, when using the above-mentioned normal superheat degree control valve without using the second electric valve EV ₄ as described above,
The liquid side main pipe 4 is provided with a bypass circuit that bypasses this superheat degree control valve, and this bypass circuit is provided with a check valve that allows flow during cooling.

Next, the first electric valve EV ₁ to
A control system for controlling EV ₃ , second electric valve EV ₄ , etc. will be explained with reference to FIG.

The controller 20 is equipped with a central processing unit (CPU) connected to a memory 21 consisting of ROM and RAM, and on the input side is an operation detection means 22 that detects whether or not indoor units B are in operation and the number of them, and whether the indoor units B are in operation or in cooling operation or heating operation. The operating mode detecting means 23 for detecting whether _the
THe is connected via the A-D converter 26, and
On the output side, a solenoid relay SV for switching the four-way switching valve 2 is connected via a drive circuit _D1 , and the first motor-operated valves _EV1 to EV are connected via a multiplexer 27 and a plurality of pulse oscillation circuits 28 to 31. ₃
and each motor of the second electric valve EV ₄ are connected, and further,
Motor relays _F1 to _F3 that control the fan motors of each fan 9 provided in the indoor unit B are controlled via drive circuits _D2 to _D4 .

Incidentally, the central processing unit (CPU) in the controller 20 controls the first motor-operated valves EV ₁ to EV ₃ corresponding to the indoor unit B that is in operation based on the detection result of the operation detection means 22. A means for adjusting the valve opening degree to a constant value according to the number of operating indoor units B, and fully closing the first motor-operated valves EV ₁ to _{EV 3} corresponding to indoor units B which are inactive during cooling, and which are inactive during heating. and a means for stopping the fan 9 of the indoor unit B and controlling the first motor-operated valves EV ₁ to EV ₃ corresponding to the indoor unit B that is inactive to a constant small opening degree. I have it too.

Next, the operations of the first and second electric valves EV ₁ to EV ₃ and EV ₄ by the above control system will be explained according to the flowcharts shown in FIGS. 4 and 5.

FIG. 4 is a flowchart during cooling, and this flowchart is executed by detecting the cooling operation state by the operation mode detection means 23.

Next, the operation detection means 22 detects the number of operating indoor units B and whether each indoor unit B is in operation to detect the operating state (step 101).
The presence or absence of a state change is determined (step 102).

Then, when all the indoor units B are stopped or suspended due to the operation of the operation switch or the room temperature detector 25 provided in each indoor unit B, and the compressor 1 is stopped, the first and second electric valves EV ₁ ~E ₃ and
The control of EV ₄ is stopped (step 103,
104) Furthermore, when any one of the indoor units B is in operation, fully closes the first electric valves EV ₁ to EV ₃ corresponding to the indoor unit B that is inactive (step 106), Indoor unit B in operation
The first motor-operated valves EV ₁ to EV ₃ corresponding to the first motor-operated valves EV 1 to EV 3 are controlled to a constant valve opening degree corresponding to the above-mentioned number of pulses in accordance with the number of the motor-operated valves in operation (step 107).

Note that during cooling, the second electric valve _EV4 is fully opened (step 108).

Further, FIG. 5 is a flowchart during heating, and as with cooling, this flowchart is executed by detecting the heating operating state.

Next, after detecting the number of operating indoor units B and whether or not each indoor unit B is in operation to detect the operating state (step 201), it is determined whether there is a change in the state (step 202).

Then, when all the units are stopped or suspended and the compressor 1 is stopped, the first and second electric valves EV ₁ to
Stop controlling EV ₃ and EV ₄ (steps 203 and 204),
In addition, if there is an indoor unit B in operation, the first electric valve EV ₁ corresponding to the indoor unit B in operation is
~ EV ₃ is controlled to a constant valve opening corresponding to the above-mentioned number of pulses depending on the number of EVs in operation (step 207).

During this heating, the seventh and eighth temperature detectors
The temperature (T ₇ ) of the low pressure gas refrigerant flowing through the suction pipe ₁₆ and the pressure equivalent saturation temperature (Te) of this low pressure gas refrigerant are detected by TH 7 and THe (step 208), and the deviation value ( E ₁ ) is calculated (step 209), and if the absolute value of the deviation value (E ₁ ) is larger than 1°C and the deviation value (E ₁ ) is smaller than zero, the valve of the second electric valve EV ₄ is The degree of opening is closed by a certain value (step 210), and when the degree of opening is greater than zero, it is opened by a certain value (step 211), and the deviation value (E ₁ ) of the degree of superheating of the low pressure gas refrigerant is set at the outlet side of the heat exchanger 3 on the heat source side. It is possible to control the target superheat degree (SH) to within ±1°C, which is set so that the degree of superheating is 0°C to 3°C.

(Second Embodiment) What is shown in FIGS. 6 to 9 is an embodiment of the second invention and the third invention, and the configuration of the refrigerant piping system is substantially the same as that shown in FIG. 1. are essentially the same.

The difference in this refrigerant piping system is that each of the liquid side branch pipes 5 has first to third temperature detectors TH for detecting the temperature of the high pressure liquid refrigerant on the outlet side during heating of each of the user side heat exchangers 8. ₁ , _TH2 , _TH3
and fourth to sixth temperature detectors TH ₄ , TH ₅ , TH for detecting the temperature of the low-pressure gas refrigerant on the outlet side during cooling of each of the usage side heat exchangers 8, respectively, in the gas side branch pipe 7. The only point is that ₆ was provided.

Further, a first electric valve interposed in the liquid side branch pipe 5
Control of EV ₁ to EV ₃ and interposed in the liquid side main pipe 4,
A second electric valve EV ₄ that controls the degree of superheating of the low-pressure gas refrigerant on the outlet side during heating of the heat source side heat exchanger 3
The control system that controls the
This embodiment is essentially the same as the first embodiment shown in the figure, but differs in that it further incorporates the following configuration. That is, as shown in FIG. 7, on the input side of the central processing unit (CPU) in the controller 20, the first to sixth temperature detectors TH ₁ to TH ₆ are connected to the seventh and eighth temperature detectors TH. ₇ , connected to THe, and connected to the central processing unit (CPU) by the following four means, that is, a first unit corresponding to the indoor unit B to be operated at the start of operation based on the detection result of the operation detection means 22. The electric valves EV ₁ to _{EV 3} are operated at a constant valve opening depending on the number of operating indoor units B, and
means for adjusting to open for a certain period of time (for example, 3 minutes); the first to third temperature detectors TH ₁ during heating;
The temperature (T ₁ to T ₃ ) of the high pressure liquid refrigerant detected by TH ₂ and TH ₃ , that is, the temperature (T ₁ to _{T 3} ) of the high pressure liquid refrigerant flowing from the indoor unit B during operation to the liquid side branch pipe 5. Means for calculating the average temperature (Tm) The average temperature (Tm) and the temperatures (T ₁ ) to (T ₃ ) of each high-pressure liquid refrigerant measured by the first to third temperature detectors TH ₁ , TH ₂ , TH ₃ The valve opening degrees of the first electric valves EV ₁ to _{EV 3} corresponding to the operating indoor unit B are adjusted, and the high pressure on the outlet side of the user-side heat exchanger 8 of the operating indoor unit B is adjusted. Means for controlling the liquid refrigerant temperature (T ₁ ) to (T ₃ ) to be close to the average temperature (Tm) In the indoor unit B which is inactive during heating,
The temperature of each high-pressure liquid refrigerant (T ₁ to T ₃ ) detected by the first to third temperature detectors TH ₁ to TH ₃ is compared with the average temperature, and the
When the temperature of the high-pressure liquid refrigerant on the outlet side of the user-side heat exchanger 8 is lower than the average temperature, the first electric valve EV ₁ corresponding to the indoor unit B that is inactive
~ EV ₃ has a built-in means for correcting the valve opening degree to the open side with respect to the above-mentioned constant opening degree.

Of the four means described above, each means of ~ is for implementing the second invention, and each of the means of ~ is for implementing the third invention.

Next, the first electric valve EV ₁ in this embodiment
- The operations of EV ₃ and second electric valve EV ₄ will be explained according to the flowcharts shown in FIGS. 8 and 9.

In these flowcharts, the control of the first electric valves EV 1 to EV 3 when all the indoor units B are stopped or inactive, and when some of the indoor units B is stopped or inactive is the first electric valve EV ₁ to _{EV 3} . Since the steps are the same as those of the embodiment, their explanation will be omitted (steps 101-107 in FIG. 8, steps 201-207 in FIG. 9).

Therefore, when some of the indoor units B are in operation, at the start of operation, the number of indoor units B in operation is detected and the first electric valves EV ₁ to 1 corresponding to the indoor units B in operation are detected. The EV ₃ is controlled to a fixed opening degree for a fixed period of time using a number of pulses depending on the number of vehicles in operation.

This control is the same as that for heating and cooling, and after the predetermined time period has elapsed, the control is performed as follows.

First, during cooling, as shown in the flowchart shown in FIG. 8, the fourth to sixth temperature detectors TH4 _to
By TH ₆ , the temperature (T ₄
~T ₆ ), and the eighth temperature detector
The pressure-equivalent saturation temperature (Te) of the low-pressure gas refrigerant is detected by THe (step 109).

and the temperature of the low pressure gas refrigerant (T ₄ to _{T 6} )
Calculate the deviation value (En) between the target superheat degree (SH ₀ ) and the pressure-equivalent saturation temperature (Te) of the low-pressure gas refrigerant, that is, En = (T ₄ , T ₅ , T ₆ ) − Te − SH ₀ . (Step 110), when the absolute value of this deviation value (En) is 1°C or more, the deviation value (En)
When is smaller than zero, the valve openings of the electric valves EV ₁ to _{EV 4} corresponding to the indoor unit B in operation are closed to a certain value (step 111), and when it is above ambience, they are opened to a certain value. (Step 112), the degree of superheating on the outlet side of each user-side heat exchanger 8 is 0°C to
It is possible to control the target superheat degree (SH ₀ ) to within ±1°C, which is set at 3°C.

The valve opening degree control of the first electric valves EV ₁ to _{EV 3} is performed by proportional control (P control), PD control, or PID control with respect to the deviation value (En).

Incidentally, during this cooling, the second electric valve EV ₄ is fully opened as in the first embodiment (step 108).

Next, during heating, the first to third temperature detectors (TH ₁ to _{TH 3} ) are activated as shown in the flowchart shown in FIG.
The temperature (T ₁ to T ₃ ) of the high-pressure liquid refrigerant flowing from the indoor unit B in operation to the liquid side branch pipe 5 is detected (step 212).

Then, from the detection results of each of these detectors TH ₁ to _{TH 3} , the average temperature (Tm) of the high-pressure liquid refrigerant flowing through the liquid side branch pipe 5 is calculated (step 213), and this average temperature (Tm) and each of the above-mentioned Compare the high pressure liquid refrigerant temperature (T ₁ to _{T 3} ) and find the deviation value (Xn),
That is, Xn = (T ₁ , T ₂ , T ₃ ) - Tm is calculated (step 214), and if the absolute value of this deviation value (Xn) is greater than 1°C, the deviation value (Xn) is When it is greater than zero, the electric valves EV ₁ to _{EV 3} corresponding to the indoor unit B in operation
The number of input pulses of the electric valves EV ₁ to _{EV 3 is controlled so that the valve opening is closed to a certain value (step 215), and when it is smaller than zero, the number of input pulses of the electric valves EV 1 to EV 3} is also opened to a certain value (step 216). User side heat exchanger 8
The temperature of the high-pressure liquid refrigerant (T ₁ to T ₃ ) on the outlet side of the refrigerant can be brought close to the average temperature (Tm) within a temperature range of ±1°C.

The above-mentioned valve opening degrees of the electric valves EV ₁ to _{EV 3} are controlled proportionally (P control) with respect to the deviation value (Xn).
Alternatively, PD control or PID control is used.
The minimum value in the closing direction is about 50 pulses, and the maximum value in the opening direction is about 200 pulses.

Further, during heating performed as described above, the second electric valve EV ₄ that controls the degree of superheating of the low-pressure gas refrigerant on the outlet side of the heat source side heat exchanger 9 is
Similarly to the embodiment, the temperature (T ₇ ) of the low-pressure gas refrigerant detected by the seventh temperature detector TH ₇ and the pressure-equivalent saturation temperature (Te) of the low-pressure gas refrigerant detected by the eighth temperature detector THe This is done by comparing (steps 208 to 211).

Also, during heating, high-pressure gas refrigerant flows from the gas side branch pipe 7 into the indoor unit B when it is inactive.
The liquefied refrigerant is liquefied by natural heat radiation in the user-side heat exchanger 8, and the liquefied liquid refrigerant opens the first electric valves EV ₁ to EV ₃ corresponding to the inactive indoor unit B at a constant small opening degree. Normally, liquid accumulation does not occur, but if the ambient temperature of indoor unit B during heating suspension drops to the same temperature as the outside air temperature due to some abnormality, the user-side heat exchanger 8 of indoor unit B The amount of natural heat dissipated from the heat exchanger 8 on the user side to the first electric valves EV ₁ to EV ₃ increases significantly, and since the gas side branch pipe 7 is not provided with a solenoid valve or the like to prevent refrigerant from flowing in. Liquid refrigerant rapidly accumulates in the refrigerant circuit leading to the refrigerant, resulting in a liquid pool. In this case, since the first motor-operated valves EV ₁ to _{EV 3} are slightly opened, the flow rate of the refrigerant in the refrigerant circuit during the pause period is very small, and therefore the subcooling of the liquid refrigerant increases rapidly.
Therefore, the high pressure refrigerant temperature (T ₁ to T ₃ ) in the indoor unit B which is inactive is detected by the first to third temperature detectors TH ₁ to TH ₃ provided in the liquid side branch pipe 5, and the temperature of each high pressure liquid refrigerant is detected. Compare the temperature (T ₁ , T ₂ , T ₃ ) with the average temperature (Tm) (step
217), if each of the high-pressure liquid refrigerants (T ₁ , T ₂ , T ₃ ) is lower than the average temperature (Tm), there is a pool of liquid; The pulse motors of the motor-driven valves EV ₁ -EV ₃ are controlled so that the motor-driven valves EV ₁ -EV ₃ are opened by a certain small opening degree to a certain value. (Step 218).

In this case, the opening correction is performed in stages with the opening corresponding to the number of pulses, for example about 5 pulses, and the lower limit of the small opening control is the aforementioned 40 pulses, and the upper limit of the correction is 70 pulses. The corresponding opening degree is set.

In the second embodiment controlled as described above, each user-side heat exchanger 8 of indoor unit B operating during cooling is
The degree of superheating on the outlet side can be adjusted appropriately, and
During heating, the degree of subcooling on the outlet side of each user-side heat exchanger 8 of the operating indoor units B can be averaged, and the uneven flow of refrigerant to each operating indoor unit B can be reduced. That is, if the connecting pipes C connecting each indoor unit B to the outdoor unit A are different in length or short, or if there is a height difference in the installation location of the indoor units B, uneven flow will occur due to pipe resistance or the like. For example, if the placement resistance is large, it is normal for the refrigerant to flow less easily, but if the refrigerant flow rate is low, supercooling will occur and the degree of supercooling will increase, so according to the second embodiment,
The first motor-operated valves EV ₁ to EV ₃ corresponding to the indoor unit B having a large piping resistance are controlled to be slightly open, and the first motor-operated valves EV ₁ to _{EV 3} corresponding to the indoor unit B having a small piping resistance are controlled to be slightly opened. Since the valves are controlled to be slightly closed, the flow rate at the first electric valves EV ₁ to EV ₃ which are controlled to be slightly opened is increased, and the degree of supercooling is controlled to be reduced.

Therefore, even if there are factors that cause uneven flow, such as piping resistance, the uneven flow can be reduced, the capacity can be appropriately distributed to each indoor unit B, and furthermore,
Since the degree of supercooling on the outlet side of the heat exchanger on the user side of each indoor unit can be brought closer to the predetermined value,
The system as a whole can be operated efficiently, improving heating capacity and improving EER.

Furthermore, in the second embodiment, the first electric valves EV ₁ to EV ₃ corresponding to the indoor unit B that is inactive are corrected by comparing the high-pressure liquid refrigerant temperature (T ₁ to T ₃ ) with the average temperature (Tm). Therefore, it is possible to reliably eliminate liquid accumulation in the indoor unit B when it is not in use, and therefore, the refrigerant can be used effectively, and a decrease in performance due to insufficient amount of refrigerant can be reliably prevented.

(Third Embodiment) The one shown in FIG. 10 is an embodiment of the fourth invention, and the configuration of the refrigerant piping system is the same as that of the first and second embodiments shown in FIGS. 1 and 6. Essentially unchanged.

The difference is that in the second embodiment shown in FIG. 6, the liquid side main pipe 4 is provided with the heat source side heat exchanger 3.
a ninth temperature detector _TH9 for detecting the temperature ( _T9 ) of the high-pressure liquid refrigerant at the outlet side of the heat exchanger 3; and a tenth temperature detector THc for detecting the condensation temperature (TC) of the high-pressure refrigerant at the heat source side heat exchanger 3. The second electric valve EV ₄ is also provided to control the degree of subcooling of the high-pressure liquid cooling at the outlet side of the heat source side heat exchanger 3 during cooling.

Therefore, the control system for controlling the first electric valves EV ₁ to EV ₃ and the second electric valve EV ₄ is different from the second embodiment shown in FIG. 7 as shown in FIG. said ninth on the input side of
The tenth temperature detector TH ₉ , THc is connected to the target supercooling degree (SC) setter 32, and the temperature detected by the ninth temperature detector TH ₉ during cooling is connected to the central processing unit (CPU). The degree of supercooling is calculated from the temperature (T ₉ ) of the high-pressure liquid refrigerant and the condensation temperature (TC) of the high-pressure liquid refrigerant detected by the tenth temperature detector THc, and the degree of supercooling is calculated from the condensation temperature (TC) and the setting. Compare the temperature (Tsc) that corresponds to the target degree of supercooling (SC) set in the device 32, and set the target degree of supercooling (SC).
The only difference is that the second motor-operated valve EV ₄ has a built-in means for adjusting the valve opening degree of the second motor-operated valve EV 4 so that the opening degree of the second motor-operated valve EV 4 is adjusted.

In addition, when implementing the fourth invention, the above-described configuration may be combined with the second embodiment that implements the above-described second and third inventions like the third embodiment;
The configuration described above may be combined with the first embodiment for carrying out the invention.

Furthermore, the control of the first and second electric valves EV ₁ to EV ₃ and EV _{4 in the third embodiment configured as described above is as explained in the second embodiment, but the control of the first and second electric valves EV 1 to EV 3 and EV 4} during cooling is Since there are differences in the control of the valve EV ₄ , only the differences will be explained according to the flowchart shown in FIG.

That is, during cooling, the second electric valve EV ₄ is controlled after being adjusted to have a constant valve opening degree at the start of operation and to open for a certain period of time (for example, 3 minutes), and this control is performed by the ninth electric valve EV 4. The temperature (T _{9 )} of the high-pressure liquid refrigerant on the outlet side of the heat source side heat exchanger 3 detected by the temperature detector TH ₉ and the tenth temperature detector
After detecting the condensing temperature (TC) detected by THc and calculating the degree of supercooling ΔT (=TC−T ₉ ) (step 313), the target degree of supercooling (SC) on the outlet side is calculated.
The deviation value (E ₂ ), that is, E ₂ =Tsc - ΔT, is calculated (step 314), and this deviation value (E ₂ ) is calculated.
When the absolute value of is greater than 1°C, and the deviation value (E ₂ ) is greater than zero, the second electric valve
The EV ₄ valve opening is closed to a certain value (step 315), and when it is smaller than zero, it is opened to a certain value (step 316), so that the degree of supercooling of the high-pressure liquid refrigerant is within ± the target degree of supercooling (SC). The number of input pulses to the second electric valve EV ₄ is controlled so that the temperature is 1°C. Note that the opening degree control of the second electric valve EV ₄ is performed by controlling the number of input pulses (for example, 180 pulses) so that a predetermined valve opening degree is achieved in place of steps 308 and 313 to 316 described above. Good too.

However, in this fourth embodiment, the above-mentioned third
While the effects of the embodiments are obtained, even during cooling, the degree of subcooling of the high-pressure liquid refrigerant can be appropriately controlled, the cooling capacity can be improved, and EER can also be improved.

In addition, in the first to third embodiments explained above, the number of connected indoor units B is three;
There may be two units, or four or more units.

Furthermore, in the second and third embodiments, the first
Although third temperature detectors TH ₁ to _{TH 3} were installed in the liquid side branch pipe 5, the usage side heat exchanger 8 of each indoor unit B
It may be provided on the exit side during heating. Also,
The fourth to sixth temperature detectors TH ₄ to _{TH 6} provided in the gas side branch pipe 7 may also be provided on the outlet side of the usage side heat exchanger 8 during cooling; however, it is preferable to provide them in the gas side branch pipe 7. Accordingly, an eighth temperature detector is installed in the detection circuit 17 provided in the outdoor unit A to detect the pressure-equivalent saturation temperature (Te) of the low-pressure gas refrigerant.
In conjunction with the provision of THe, there is no need to route signal wiring between the indoor and outdoor units A and B, and the wiring between these indoor and outdoor units A and B can be simplified accordingly.

(Effects of the Invention) The effect of the first invention is that, even without using a solenoid valve in the gas side branch pipe 7 as in the conventional example, the first motor-operated valves EV ₁ to EV ₃ corresponding to the indoor unit B that is inactive are fully activated during cooling. Since the first electric valve is closed and controlled to a small opening during heating, it is possible to reliably prevent liquid from accumulating in the indoor unit B that is inactive, and the first electric valve that corresponds to the indoor unit B that is in operation can be reliably prevented. EV ₁ to EV ₃ are
Since the opening degree is controlled to be constant depending on the number of operating indoor units B, the degree of superheating of the low-pressure gas refrigerant at the outlet side of the user-side heat exchanger 8 is controlled during cooling, and the degree of superheating of the low-pressure gas refrigerant on the outlet side of the user-side heat exchanger 8 is controlled during heating. The degree of supercooling of the high-pressure liquid refrigerant at the outlet side of the refrigerant can be controlled.

Therefore, not only during cooling but also during heating,
The capacity of each indoor unit B to be operated can be improved, and the capacity can also be appropriately distributed.

Moreover, since the superheat degree control valve EV ₄ is installed in the liquid side main pipe 4, the superheat degree control valve EV ₄ controls the degree of superheat of the low-pressure gas refrigerant in the heat source side heat exchanger 3 during heating. Therefore, during heating, the degree of superheating can be controlled while controlling the degree of supercooling of the high-pressure liquid refrigerant using the first electric valves EV ₁ to _{EV 3} corresponding to the operating indoor unit B.
Heat source side heat exchanger 3 acts as an evaporator during heating
The heat exchange action of the user-side heat exchanger 8, which also acts as a condenser, is performed efficiently, improving the heating capacity.
In addition to improving EER, the superheat control valve
Since the degree of superheating is controlled by EV ₄ , the refrigerant can be appropriately distributed to each indoor unit B.

Further, according to the first invention, the gas side branch pipe 7 does not need to be provided with a solenoid valve as in the conventional example, and
While the degree of superheating can be appropriately controlled for both heating and cooling, it is only necessary to provide one liquid receiver 10 in the liquid side main pipe 4 instead of using many liquid receivers as in the conventional example, so the number of parts can be reduced, and The refrigerant circuit can be simplified.

Further, the effect of the second invention is that the first electric valves EV ₁ to EV ₃ corresponding to the indoor unit B operated during heating are connected to the user-side heat exchanger 8 while the above-mentioned effects are obtained.
Since the temperature of each high-pressure liquid refrigerant on the outlet side during heating (T ₁ to T ₃ ) is compared with the average temperature (Tm) of each of these temperatures (T ₁ to T ₃ ), control is performed. The degree of subcooling of the high-pressure liquid refrigerant can be controlled according to the indoor load, and while each of the heat exchangers 8 on the user side can be used effectively, the unbalanced flow to the indoor unit B can be reduced, and the capacity distribution described above can be improved. It can be done accurately, and the degree of supercooling can be controlled more appropriately, so heating capacity can be further improved.
This also makes it possible to improve EER.

Further, the effect of the third invention is that while the effects of the first and second inventions described above are obtained, the first electric valves EV ₁ to _{EV 3} corresponding to the indoor unit B that is inactive during heating are
The temperature (T 1 to T 3 ) of the high-pressure liquid refrigerant on the outlet side of the user-side heat exchanger 8 during heating, that is, the fan 9 is stopped, and the temperature (T ₁ to T ₃ ) of the high-pressure liquid refrigerant that liquefies due to natural heat radiation is set to the average temperature (Tm ), when the temperature (T ₁ to _{T 3} ) is low, the first opening is controlled to a constant small opening.
Since the valve opening degrees of the electric valves EV ₁ to _{EV 3} are controlled from a small opening degree to a constant value, it is possible to more reliably prevent liquid from accumulating in the indoor unit B when the indoor unit B is inactive during heating.

Further, the effect of the fourth invention is that while the effect of the first invention is obtained, the second electric valve interposed in the liquid side main pipe 4
Since EV ₄ can control the degree of subcooling of the low-pressure gas refrigerant on the outlet side of the heat source side heat exchanger 3 during cooling, and the degree of superheating of the high-pressure liquid refrigerant during heating, the first electric valves EV ₁ to _{EV 3} In addition to controlling the degree of superheating during cooling and the degree of subcooling during heating,
The degree of superheating during cooling can be controlled by the second electric valve, and therefore, in both heating and cooling, the heat exchange action of the heat source side heat exchanger and the user side heat exchanger is performed efficiently, increasing the heating and cooling capacity and increasing the EER. This means that improvements in performance can be achieved with certainty.

[Brief explanation of drawings]

Fig. 1 is a refrigerant piping system diagram showing an embodiment of the first invention, Fig. 2 is an opening characteristic diagram of an electric valve, Fig. 3 is a schematic explanatory diagram of a controller, Fig. 4 is a flowchart during cooling, Fig. 5 is a flowchart during heating, Fig. 6 is a refrigerant piping system diagram showing embodiments of the second and third inventions, Fig. 7 is a schematic explanatory diagram of the controller, and Fig. 8 is a flowchart during cooling. Fig. 9 is a flowchart during heating, Fig. 10 is a refrigerant piping system diagram showing an embodiment of the fourth invention, Fig. 11 is a schematic explanatory diagram of the controller, and Fig. 12 is a flowchart during cooling. , FIG. 13 is a refrigerant piping system diagram of a conventional example. 1... Compressor, 2... Four-way switching valve, 3... Heat source side heat exchanger, 4... Liquid side main pipe, 5... Liquid side branch pipe,
6...Gas side main pipe, 7...Gas side branch pipe, 8...Using side heat exchanger, 9...Fan, 10...Liquid receiver,
22...Operation detection means, A...Outdoor unit, B
...Indoor unit, EV ₁ to EV ₃ ...First electric valve,
EV ₄ ...Second electric valve, TH ₁ to _{TH 3} ... High pressure liquid refrigerant temperature detection means.

Claims (1)

[Claims] 1 Compressor 1, four-way switching valve 2, heat source side heat exchanger 3
and one outdoor unit A comprising a liquid side main pipe 4, a plurality of liquid side branch pipes 5 branching from the liquid side main pipe 4, a gas side main pipe 6 and a plurality of gas side branch pipes 7 branching from the gas side main pipe 6. and the user side heat exchanger 8 and fan 9
and a plurality of indoor units B connected in parallel between the liquid side branch pipe 5 and the gas side branch pipe 7, the multi-room air conditioner is capable of heating and cooling by switching the four-way switching valve 2. In the device, the liquid-side branch pipe 5 is provided with first motor-operated valves EV ₁ to EV ₃ whose opening degree can be adjusted from fully closed to any desired opening degree, and the liquid-side main pipe 4 is provided with , a superheat degree control valve EV ₄ that controls the superheat degree of the low-pressure gas refrigerant on the outlet side of the heat source side heat exchanger 3 during heating is interposed, and superheat degree control is performed with the first electric valves EV ₁ to EV ₃ . One liquid receiver 10 is interposed in the main liquid side pipe 4 between the valve EV ₄ and an operation detecting means 22 for detecting whether or not the indoor unit B is in operation and the number of the indoor units B; Based on the results, the first electric valves EV ₁ to _{EV 3} corresponding to the operating indoor unit B are selected.
means for adjusting the opening to a constant degree in accordance with the number of operating indoor units B; and means for adjusting the first electric valves EV ₁ to _{EV 3} corresponding to the indoor units B that are inactive during cooling.
means for fully closing the fan 9 of the indoor unit B that is inactive during heating, and controlling the first electric valves EV ₁ to EV ₃ corresponding to the indoor unit B that is inactive to a small opening degree. A multi-room air conditioner characterized by comprising: 2 Compressor 1, four-way switching valve 2, heat source side heat exchanger 3
and a liquid side main pipe 4, a plurality of liquid side branch pipes 5 branching from the liquid side main pipe 4, a gas side main pipe 6, and the gas side main pipe 6.
One outdoor unit A is equipped with a plurality of gas side branch pipes 7 branching from the liquid side branch pipe 5 and a user side heat exchanger 8 and a fan 9 are arranged in parallel between the liquid side branch pipe 5 and the gas side branch pipe 7. This multi-room air conditioner is composed of a plurality of connected indoor units B, and is capable of heating and cooling by switching the four-way switching valve 2, and the liquid side branch pipe 5 has a valve opening that can be adjusted from fully closed to any desired degree. First electrically operated valves EV ₁ to _{EV 3} each of which can be adjusted to an opening degree of By installing a superheat control valve EV ₄ to control the temperature,
One liquid receiver 10 is interposed in the liquid side main pipe 4 between the first electric valves EV ₁ to _{EV 3} and the superheat degree control valve EV ₄ , and the presence or absence of operation of the indoor unit B and the number of units are detected. and, based on the detection result of the operation detection means 22, the first electric valve EV ₁ corresponding to the indoor unit B to be operated at the start of operation.
- Means for adjusting the EV ₃ to be opened at a constant valve opening degree and for a certain period of time according to the number of operating indoor units B, and an indoor unit B that is operated during heating.
means TH _{1 to TH 3 for} detecting the temperature of the high pressure liquid refrigerant on the outlet side of the utilization side heat exchanger 8 in means for calculating the average temperature of the refrigerant, and comparing the average temperature with the detection results of the liquid refrigerant temperature detection means TH ₁ to _{TH 3} , and calculating the first electric valve corresponding to the operating indoor unit B. EV ₁
- A means for controlling the temperature of the high-pressure liquid refrigerant on the outlet side of the user-side heat exchanger 8 of the indoor unit B during operation to approach the average temperature by adjusting the valve opening degree of the EV ₃ ; Fully close the first electric valves EV ₁ to _{EV 3} corresponding to indoor unit B, stop the fan 9 of indoor unit B that is inactive during heating,
A multi-room air conditioner characterized by comprising: means for controlling the first electric valves EV ₁ to _{EV 3} corresponding to the inactive indoor unit B to a small opening degree. 3 Compressor 1, four-way switching valve 2, heat source side heat exchanger 3
and a liquid side main pipe 4, a plurality of liquid side branch pipes 5 branching from the liquid side main pipe 4, a gas side main pipe 6, and the gas side main pipe 6.
One outdoor unit A is equipped with a plurality of gas side branch pipes 7 branching from the liquid side branch pipe 5 and a user side heat exchanger 8 and a fan 9 are arranged in parallel between the liquid side branch pipe 5 and the gas side branch pipe 7. This multi-room air conditioner is composed of a plurality of connected indoor units B, and is capable of heating and cooling by switching the four-way switching valve 2, and the liquid side branch pipe 5 has a valve opening that can be adjusted from fully closed to any desired degree. First electrically operated valves EV ₁ to _{EV 3} each of which can be adjusted to an opening degree of By installing a superheat control valve EV ₄ to control the temperature,
One liquid receiver 10 is interposed in the liquid side main pipe 4 between the first electric valves EV ₁ to _{EV 3} and the superheat degree control valve EV ₄ , and the presence or absence of operation of the indoor unit B and the number of units are detected. and, based on the detection result of the operation detection means 22, the first electric valve EV ₁ corresponding to the indoor unit B to be operated at the start of operation.
- Means for adjusting the EV ₃ to be opened at a constant valve opening degree and for a constant time depending on the number of operating indoor units B, and an outlet side of the user-side heat exchanger 8 in the indoor unit B operating during heating. means for detecting liquid refrigerant temperature TH ₁ to _{TH 3} ;
means for calculating the average temperature of the high-pressure liquid refrigerant flowing through each liquid side branch pipe 5 from the detection result of TH ₃ ; and means for detecting the average temperature and each liquid refrigerant temperature TH ₁ -
The valve opening degree of the first electric valve EV ₁ to EV 3 corresponding to the operating indoor unit B is compared with the detection result of TH ₃ , and the opening degree of the first electric valve EV 1 to _{EV 3} corresponding to the operating indoor unit B is adjusted. 8, the means for controlling the temperature of the high-pressure liquid refrigerant on the outlet side to be close to the average temperature, and fully closing the first electric valves EV ₁ to _{EV 3} corresponding to the indoor unit B that is inactive during cooling, and the unit is inactive during heating. Means for stopping the fan 9 of the indoor unit B in the indoor unit and controlling the first electric valves EV ₁ to EV ₃ corresponding to the indoor unit B in the inactive state to a small opening degree; In the indoor unit B, the detection results detected by the high-pressure liquid refrigerant temperature detection means TH ₁ to _{TH 3} are compared with the above-mentioned average temperature, and the high pressure on the outlet side of the user-side heat exchanger 8 in the indoor unit B that is inactive is compared. When the liquid refrigerant temperature is lower than the average temperature, the first electric valve corresponds to the indoor unit B that is inactive.
A multi-chamber air conditioner characterized by comprising means for correcting the valve opening degrees of EV ₁ to _{EV 3} to the open side. 4 Compressor 1, four-way switching valve 2, heat source side heat exchanger 3
and a liquid side main pipe 4, a plurality of liquid side branch pipes 5 branching from the liquid side main pipe 4, a gas side main pipe 6, and the gas side main pipe 6.
One outdoor unit A is equipped with a plurality of gas side branch pipes 7 branching from the liquid side branch pipe 5 and a user side heat exchanger 8 and a fan 9 are arranged in parallel between the liquid side branch pipe 5 and the gas side branch pipe 7. This multi-room air conditioner is composed of a plurality of connected indoor units B, and is capable of heating and cooling by switching the four-way switching valve 2, and the liquid side branch pipe 5 has a valve opening that can be adjusted from fully closed to any desired degree. First electrically operated valves EV ₁ to _{EV 3} each of which can be adjusted to an opening degree of The first electric valve EV _{4 is interposed between the second electric valve EV 4} and the first electric valve EV 4.
Liquid side main pipe ₄ between EV ₁ to EV ₃ and second electric valve EV 4
One liquid receiver 10 is installed in the indoor unit B, and an operation detection means 22 detects whether or not the indoor units B are in operation and the number of them, and based on the detection results of this operation detection means 22, the operating indoor units are detected. means for adjusting the first electric valves EV ₁ to _{EV 3} corresponding to the first electric valves EV 1 to EV 3 corresponding to the indoor units B to a constant opening according to the number of operating indoor units B; The electric valves EV ₁ to EV ₃ are fully closed, the fan 9 of the indoor unit B that is inactive during heating is stopped, and the first electric valves EV ₁ to EV ₃ corresponding to the indoor unit B that is inactive are closed. A multi-room air conditioner characterized by comprising means for controlling the opening to a small degree.