JPH02223757A - Air conditioner - Google Patents

Abstract

PURPOSE:To defrost automatically by limiting/halting the supply of refrigerant to an indoor unit when a frosting signal is input from a temperature sensor of a cooling side indoor unit in heating operation mode during simultaneous cooling and heating operation. CONSTITUTION:Assuming that indoor units 11 and 12 are called for to perform heating operation while an indoor unit 13 is demanded to perform cooling operation, heating mode is selected since heating load is greater than cooling load. As a result, a two way valve 23 is closed while a two way valve 26 is opened so that an outdoor heat exchanger 3 may serve as a vaporizer where high temperature discharged refrigerant from a compressor 1 is introduced into the indoor units 11 and 12 by way of a valve circuit of a multi-control unit B and returns by way of flow rate control valves 14a, and 14b and a heating expansion valve 4. Moreover, a part of the refrigerant after the heating is introduced into the indoor unit 13 by way of a flow rate control valve 14c and a cooling expansion valve 15. When frosting on an indoor heat exchanger 13a is detected with a temperature sensor 34c, a control means 8b closes the flow rate valve 14c. It is, therefore, possible to defrost automatically and maintain a sufficient cooling capacity as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a multi-type air conditioner that can operate cooling and heating simultaneously according to the demands of each indoor unit.

(Prior Art) A multi-type air conditioner is known in which one outdoor unit and a plurality of indoor units are connected by refrigerant piping to form a heat pump refrigeration cycle. This multi-type air conditioner is configured as shown in FIG. 14, for example.

That is, A is an outdoor unit, and this outdoor unit A is equipped with a variable capacity compressor (hereinafter referred to as compressor 1) using an inverter, and its discharge side is connected to an outdoor heat exchanger 3 via a four-way valve 2. It is connected. This outdoor heat exchanger 3 is connected to a liquid tank 6 via a parallel circuit of a heating expansion valve 4 and a check valve 5, and this is connected to a plurality of indoor units via a multi-control unit B, which will be described later. There is.

The indoor unit includes first, second, and third indoor units 11, 12, and 13, and the multi-control unit B includes the first to third indoor units 11, 12, and 13.
Refrigerant electronic flow control valves 14a, 14b, and 14c connected to the liquid tank 6 are provided corresponding to 1 to 13, and are connected to the liquid tank 6 through a parallel circuit of the check valve 16 and the cooling expansion valve 15. It is connected to third indoor units 11-13. In addition, the first to third indoor units 11 to 13
are connected to the four-way valve 2 via independently provided two-way valves 17. In addition, 7 is an outdoor fan, 8a, 8
b and 8c are control units, respectively, and the outdoor unit A1
The multi-control unit B and the first to third indoor units 11 to 13 are controlled.

Therefore, when the first to third indoor units 11 to 13 are operated for cooling, the refrigerant discharged from the compressor 1 passes through the four-way valve 2 and is condensed and liquefied in the outdoor heat exchanger 3 as shown by the solid arrow. . The liquefied refrigerant has a check valve 4, a liquid tank 6,
It passes through the electronic flow control valves 14as 14bs 14cs and is evaporated in the indoor heat exchanger of the first indoor unit 11 through the cooling expansion valve 15. In addition, the first to third indoor units 11 to
13 in heating operation, the refrigerant discharged from the compressor 1 is guided to the first to third indoor units 11 to 13 through the four-way valve 2, the two-way valve 17, and so on, as shown by the broken line arrow. ,
Heat is radiated by each indoor heat exchanger.

In this way, the cooling operation or the heating operation can be performed according to the requests of the first to third indoor units 11 to 13, and the
It is also possible to perform cooling operation or heating operation on only one or two of the third indoor units 11 to 13, and stop the rest.

(Problems to be Solved by the Invention) However, as described above, although conventional multi-type air conditioners can switch between cooling operation and heating operation, they cannot meet the individual requirements of the indoor units. In other words, in buildings with computer rooms, large buildings with perimeter zones, and interior zones, requests for cooling operation and heating operation may occur at the same time, and not only in buildings but also in general households. In the middle season,
For example, if cooling operation and heating operation are requested at the same time, such as when the first and second indoor units 11 and 12 request cooling operation and the third indoor unit 13 requests heating operation, the operation cannot be performed. Prioritize driving for one or the other.
The problem is that you can't drive the other one.

This invention was made with attention to the above-mentioned circumstances, and its purpose is to simultaneously perform cooling and heating operations according to the individual requests of each indoor unit, and to simultaneously perform cooling and heating operations. , when the heating load is greater than the cold storage mode, so-called heating priority mode, even if frost forms on the indoor unit during cooling operation on the non-priority side, this air can be detected and automatically defrosted. Our goal is to provide a harmonizing machine.

[Structure of the invention]

(Means and Effects for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides temperature sensors in each indoor unit, and allows the multi-control unit to control the cooling temperature according to the individual requirements of each indoor unit. The present invention includes a refrigerant flow switching means that enables simultaneous operation of heating and heating, and means for controlling the supply of refrigerant to each indoor unit.

When cooling and heating are in simultaneous operation and the heating load is larger than the cooling load, which is the so-called heating priority mode, the frost formation signal from the temperature sensor of the indoor unit during the cooling operation on the non-priority side is detected. The purpose of this feature is to stop or limit the supply of refrigerant to the indoor unit that is in cooling operation when input, and to automatically defrost the air.

(Embodiments) Hereinafter, each embodiment of the present invention will be described based on the drawings, and the same components as shown in FIG.

1 to 5 show a first embodiment, in which a compressor 1
The discharge side thereof is branched into a first discharge pipe 21 and a second discharge pipe 22. The second discharge pipe 22 is connected to the outdoor heat exchanger 3 via a first two-way valve 23. Further, the suction side of the compressor 1 is also branched into a first suction pipe 24 and a second suction pipe 25, and the second suction pipe 25 is connected to the first two-way valve via a second two-way valve 26. The second valve between the valve 23 and the outdoor heat exchanger 3
It is connected to the discharge pipe 22 of.

Further, on the liquid line side of the outdoor heat exchanger 3, a check valve 27 is provided in series with the heating expansion valve 4, and an electronic flow control valve 28 is provided in series with the check valve 5. 28 is provided in parallel with the heating expansion valve 4.

On the other hand, the first discharge pipe 21 is branched corresponding to the first to third indoor units 11 to 13, and is connected to the first to third indoor units via third two-way valves 29a to 29c. It is connected to the indoor heat exchangers 11a to 13a of the units 11 to 13. Further, the first suction pipe 24 is also branched corresponding to the first to third indoor units 11 to 13, and is connected to the third two-way valves 29a to 29a through the fourth two-way valves 30a to 30c. 2
9c and the first to third indoor units 11 to 13.

Various detection means and control means are added to the multi-type refrigeration cycle configured in this way. That is, as detection means, a pressure sensor 31 is provided on the gas line side of the outdoor heat exchanger 3, a first temperature sensor 32 is provided on the liquid line side, and a first temperature sensor 32 is provided on the liquid line side of the multi-control unit B. A second temperature sensor 33 is provided. Further, the first to third indoor units 13
The indoor heat exchangers 11a to 13a are provided with heat exchanger temperature sensors 34a to 34c for detecting their temperatures. Moreover, as a control means, the outdoor control part 8a is used.

A multi-control unit 8b and an indoor control unit 8c are provided.

Next, each of the control sections 8a to 8c will be explained based on FIG. 2. First, the outdoor control section 8a consists of a microcomputer and its peripheral circuits, and is connected to inverter circuits 51 and 52 externally.

The inverter circuits 51 and 52 rectify the voltage of the AC power FA 53, convert it into an AC voltage of a predetermined frequency by switching according to a command from the outdoor control unit 8a, and supply the voltage to the motor IM of the compressor 1 and the motor 7M of the outdoor fan 7. Each of these is supplied as driving power.

The multi-control unit 8b consists of a microcomputer and its peripheral circuits, and externally includes an electronic flow control valve 14, 28, third two-way valves 29a to 29c, and a fourth two-way valve 3.
0a to 30c are connected. Further, detection signals from heat exchanger temperature sensors 34a to 34c that detect the temperatures of the indoor heat exchangers 11a to 13a are inputted to the multi-control unit 8b.

Furthermore, the indoor control section 8c is provided independently in each of the first to third indoor units 11 to 13, and consists of a microcomputer and its peripheral circuits. A temperature sensor 55 is connected.

Next, the operation of the multi-type air conditioner configured as described above will be explained.

FIG. 3 shows a case where the first and second indoor units 11, 12 are in heating operation, and the third indoor unit 13 is in cooling operation. In this case, the heating load is greater than the cooling load, so
The system selects heating mode and operates with priority.

That is, the first two-way valve 23 of the outdoor unit A is closed, the second two-way valve 26 is open, and the outdoor heat exchanger 3 is connected to the compressor 1.
It communicates with the second suction pipe 25 and functions as an evaporator.

On the other hand, the third two-way valve 29 of multi-control unit B
a, 29b are open, two-way valve 29c is closed, fourth two-way valve 30a, 30b is closed, and two-way valve 30c is open. Therefore, the first and second indoor units 11.12 communicate with the first discharge pipe 21 of the compressor 1, and the third indoor unit 1
3 communicates with the suction side of the compressor 1 via a first suction pipe 24. Further, the operating frequency of the compressor 1 is determined by the inverter circuit 51 so that the capacity of the heating side, which has a large load, can be sufficiently produced.

In this state, the compressor 1, the outdoor fan 7 and the first to third
Indoor fans of indoor units 11 to 13 (not shown)
When the refrigerant is driven, the flow of the refrigerant becomes as shown by the arrow in Fig. 3, and the refrigerant discharged from the compressor 1 is guided to the first and second indoor units 11 and 12, heated by the unit, and liquefied. be done. The liquefied refrigerant is controlled by a check valve 16, an electronic flow control valve 14a,
14b and comes out to the liquid line. At this time, the opening degree of the electronic flow control valves 14a and 14b is controlled according to the indoor load, and the flow rate distribution between the first and second indoor units 11 and 12 is controlled. The operating frequency of the compressor 1 is determined by the inverter circuit 51 so that the capacity of the heating side, which has a large load, can be sufficiently produced, so that the heating capacity can correspond to the load.

A part of the liquefied refrigerant flows to the third indoor unit 13 side, and the remaining part flows to the outdoor unit A side. The refrigerant flowing toward the third indoor unit 13 is controlled by the electronic flow control valve 1.
After passing through the 4C1 cooling expansion valve 15 and being depressurized, the air is led to the third indoor unit 13, where it is cooled and then sucked into the compressor 1. At this time, the electronic flow control valve 14c connected to the third indoor unit 13 is fully opened, and the cooling expansion valve 15 controls the flow rate. Since the flow rate is controlled so that the superheat 15s of the outlet gas refrigerant is constant, the third indoor unit 13 can produce a certain capacity determined by the size of the third indoor unit 13 and the indoor temperature.

Note that the electronic flow rate control valve 14c connected to the third indoor unit 13 is normally fully open, but when the temperature sensor 55 for detecting room temperature of the third indoor unit 13 senses the set room temperature and stops, it is closed to the outside. From the control unit 8c to the multi-control unit 8
It is closed by the signal input to b.

Further, as described above, the liquid refrigerant flowing to the outdoor unit A is depressurized by the heating expansion valve 4, evaporated in the outdoor heat exchanger 3, and further merges with the refrigerant from the third indoor unit 13. It is sucked into the compressor 1. At this time, the heating expansion valve 4 is controlled so that the superheat 4s of the refrigerant after merging and before being sucked into the compressor 1 is constant. At this time, the detection signal of the pressure sensor 31 provided on the gas line side of the outdoor heat exchanger 3 is input to the indoor control unit 8a, which controls the voltage supplied to the motor 7M that drives the outdoor fan 7, and the pressure The air volume of the outdoor fan 7 is controlled so that the pressure of the sensor 31 becomes a constant value. This is a control to prevent, for example, when the outside temperature is high, the evaporation temperature of the cycle becomes high and the cooling capacity of the third indoor unit 13 is not achieved. In other words, as shown in Figure 4, as the outside air temperature rises, the evaporation pressure rises, and the
kg/eel G is exceeded, the voltage to the motor 7M of the outdoor fan 7 decreases, and the air volume of the outdoor fan 7 decreases. In this case, the amount of evaporation in the outdoor heat exchanger 3 decreases,
Since the liquid tends to back up, the restriction of the heating expansion valve 4 increases. Therefore, the evaporation temperature is lowered, and the evaporation temperature in the room is also lowered, so that sufficient cooling capacity can be achieved. By controlling the air volume of the outdoor fan 7 in this way, sufficient cooling operation capacity can be obtained.

By the way, as mentioned above, the first and second indoor units 1
1.12 is in heating operation and the third indoor unit 13 is in cooling operation, when the outside air temperature becomes 01C or less, the indoor heat exchanger 13a of the third indoor unit 13 also becomes 0''C or less. However, the temperature of the indoor heat exchanger 13a is detected by the heat exchanger temperature sensor 34c, and the detection signal is input to the multi-control unit 8b.Therefore, as shown in the flowchart of FIG. When the exchange temperature sensor 34c detects 0''C or less (step 1), the timer turns on (step 2), and when the timer time elapses for a certain period of time, for example 30 minutes (swipe 3),
A close signal (
Step 4) is entered, the electronic flow control valve 14c is closed, and the supply of refrigerant to the third indoor unit 13 is stopped.

At this time, since the indoor fan continues to rotate, the frost on the indoor heat exchanger 13a is melted by the indoor air. Then, when defrosting of the indoor heat exchanger 13a is completed and the heat exchanger temperature sensor 34c detects 5''C or more (step 5), the electronic flow control valve 14a is opened by a signal from the multi-control unit 8b, and the Refrigerant is supplied to the indoor unit 13 of No. 3, and cooling operation is started again.

During this kind of defrosting, the indoor fan is running, so
Since the frost is melted, cold air is blown out to continue the cooling operation, and the heating operation of the first and second indoor units 11 and 12 generates heating capacity according to the load by absorbing heat from the outdoor heat exchanger 3. This allows normal heating operation to be maintained.

FIG. 6 shows a second embodiment, in which each indoor unit 1
Electron flow control valves 35a to 35c are provided between the two-way valves 1 to 13 and the third two-way valves 29a to 29c.

Then, as in the first embodiment, the first and second indoor units 11 and 12 perform heating operation, and the third indoor unit 13
When the third indoor unit 13 is in cooling operation, when the outside air temperature is low and the evaporation temperature of the outdoor heat exchanger 3 and the indoor heat exchanger 13a becomes 109C or lower, the indoor heat exchanger 13a of the third indoor unit 13
The heat exchanger temperature sensor 34c detects this temperature, and the detection signal is input to the multi-control unit 8b, and the electronic flow control valve 3
The opening degree of 5c is controlled based on FIG. That is, by controlling the opening degree of the electronic flow rate control valve 35c on the outlet side of the third indoor unit 13a according to the evaporation temperature, the outdoor heat exchanger can be changed from the pattern shown in FIG. 8 to the one shown in FIG. 3 and the evaporation temperature of the indoor heat exchanger 13a changes,
Even if the temperature of outdoor heat exchanger 3 becomes low, indoor heat exchanger 1
The evaporation humidity of 3a becomes 0''C or higher, which prevents the third indoor unit 13 from freezing and allows continued cooling operation.

FIG. 10 shows a third embodiment, in which a fourth two-way valve 3
0a to 30c, and in parallel thereto, fifth two-way valves 36a to 3
6c and capillary tubes 37a to 37c are connected.

Then, as in the first and second embodiments, when the first and second indoor units 11 and 12 are in heating operation and the third indoor unit 13 is in cooling operation, the outside air temperature is low and the outdoor air temperature is low. When the evaporation temperature of the heat exchanger 3 and the indoor heat exchanger 13a becomes 56C or less, the indoor heat exchanger 1 of the third indoor unit 13
The heat exchanger temperature sensor 34c of 3a detects this temperature, and the detection signal is input to the multi-control unit 8b, which closes the fourth two-way valve 30c and closes the fifth two-way valve 30c, as shown in FIG. 36
By opening c, the evaporation temperature (pressure) decreases.

By repeating this pattern, the indoor heat exchanger 13a
The evaporation temperature (pressure) of the air can be controlled within a certain range, ensuring sufficient cooling capacity.

FIG. 12 shows a fourth embodiment, in which the fourth two-way valve 3
0a to 30e, and in parallel thereto, electronic flow control valves 38a to 38e.
38c is connected. This electronic flow control valve 38
A to 38c are normally fully open.

Then, as in the first, second and third embodiments, the first
, when the second indoor units 11 and 12 are in heating operation and the third indoor unit 13 is in cooling operation, the outside air temperature is low and the evaporation temperature of the outdoor heat exchanger 3 and the indoor heat exchanger 13a is 10". When the temperature is below C, the heat exchanger temperature sensor 34c of the indoor heat exchanger 13a of the third indoor unit 13 detects this temperature, and the detection signal is input to the multi-control unit 8b.
The electronic flow control valves 38a to 38c are fully opened, and then the fourth
The two-way valves 30a to 30c are closed. Furthermore, if the evaporation temperature decreases, the opening degrees of the electronic flow control valves 38a to 38c are adjusted to the seventh level.
By gradually narrowing down the air in the pattern shown in the figure, the evaporation temperature can be controlled within a certain range, and sufficient cooling capacity can be obtained.

FIG. 13 shows a fifth embodiment. In each of the embodiments described above, throttle devices were provided corresponding to the first to third indoor units 11 to 13, but this embodiment Valve 30a-3
One electronic flow control valve 39 is provided between 0c and the suction side of the compressor 1. This electronic flow control valve 39 is normally in a fully open state. Once the evaporation temperature is lowered, the evaporation temperature can be controlled within a certain range by gradually reducing the opening degrees of the electronic flow control valves 38a to 38c in the pattern shown in FIG. 7, and sufficient cooling capacity can be obtained.

Note that the number of indoor units is not limited to three, and may be four or more.

〔Effect of the invention〕

As explained above, according to the present invention, cooling and heating can be operated simultaneously according to the requirements of each indoor unit,
It is possible to operate cooling and heating in different rooms at the same time, and can cope with requests for cooling and heating operations that occur at the same time in buildings with computer rooms, perimeter zones, and large buildings with interior zones. Furthermore, they have the effect of being able to produce appropriate performance despite disturbances such as fluctuations in outside temperature. Furthermore, in heating operation mode where cooling and heating are running simultaneously, even if frost forms on the indoor unit during cooling operation, this can be detected and automatically defrosted, ensuring sufficient cooling capacity. be.

[Brief explanation of the drawing]

Figures 1 to 5 show a first embodiment of the present invention, in which Figure 1 is a system diagram of the refrigeration cycle of an air conditioner, Figure 2 is a control circuit diagram, and Figure 3 is a heating operation mode. FIG. 4 is an explanatory diagram of outdoor fan control; FIG. 5 is a flowchart; FIG. Figure 7 is an explanatory diagram showing the relationship between evaporation temperature and the opening degree of the electronic flow control valve.
FIG. 8 is a Mollier diagram of a conventional cycle, FIG. 9 is a Mollier diagram of a cycle of the present invention, and FIG. 10 is a system diagram of a refrigeration cycle in heating operation mode showing a third embodiment of the present invention. Fig. 11 is an explanatory diagram showing the relationship between evaporation temperature and two-way valve, Fig. 12 is a system diagram of a refrigeration cycle in heating operation mode showing the fourth embodiment of the present invention, and Fig. 13 is a diagram showing the fifth embodiment of the invention. Fig. 14 is a system diagram of a conventional refrigeration cycle in a heating operation mode showing an embodiment of the present invention. A...Outdoor unit, B...Multi control unit, 1...Compressor, 3...Outdoor heat exchanger, 11
．． 12.13...Indoor unit, 118%12a%1
3a...-indoor heat exchanger, 34a-34c... temperature sensor. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 3 Figure Opening degree Figure Figure 11

Claims (1)

[Claims] An outdoor unit equipped with a compressor, an outdoor heat exchanger, and an outdoor fan, a plurality of indoor units equipped with an indoor heat exchanger and an indoor fan, and a multi-control that controls the refrigerant flow rate and refrigerant flow path for each of the indoor units. In a multi-type air conditioner equipped with a unit, each indoor unit is provided with a temperature sensor, and the multi-control unit is capable of simultaneously operating cooling and heating according to individual requests of each indoor unit. Supplying refrigerant to the indoor unit in cooling operation when inputting a frost formation signal from the temperature sensor of the indoor unit in cooling operation when the refrigerant flow switching means and the heating operation mode are in simultaneous operation of cooling and heating. An air conditioner characterized by being provided with a control means for stopping or restricting.