JPH0464849A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable a stable operation to be easily carried out by a method wherein an air conditioner is comprised of an outdoor device, a plurality of indoor devices, a heat pump type freezing cycle, a flow rate adjusting valve, means for running a heating operation, means for controlling a capacity of a variable compressor, means for controlling the flow rate adjusting valve and means for opening the flow rate adjusting valve to a predetermined degree of opening. CONSTITUTION:A capacity variable compressor 1' is energized and its capacity is controlled in response too a sum of required capacities of indoor devices B1, B2 and B3. Concurrently, a four-way valve 2 is changed over. Accordingly, refrigerant discharged from the variable capacity comperssor 1' passes through the four-way valve 2, flows into an indoor heat exchanger 12 and thus the refrigerant is reprieved of heat by indoor air and then the refrigerant is condensed. The refrigerant passed through the indoor heat exchanger 12 flows through the flow rate adjusting valve 14 and an expansion valve 4, further flows into an outdoor heat exchanger 3, where the refrigerant retries heat from the surrounding air and evaporates. The refrigerant passes through the outdoor heat exchanger 3 and through the four-way valve 2. The refrigerant is sucked into the variable capability compressor 1! An indoor fan is turned on for its operation in the indoor device B1 and the indoor air is circulated through the 'indoor heat exchanger 12 and then the heating operation is carried out at the indoor device B1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a multi-type air conditioner consisting of an outdoor unit and a plurality of indoor units.

(Prior Art) In buildings and the like having a plurality of rooms, multi-type air conditioners consisting of an outdoor unit and a plurality of indoor units are used to collectively air-condition each room.

An example of this multi-type air conditioner is shown in FIG.

In the figure, 1 is a compressor, and a four-way valve 2 is located on the discharge side of the compressor 1.
The outdoor heat exchanger 3 is connected via the .

A pressure reducer such as an expansion valve 4 is connected to the outdoor heat exchanger 3, and the expansion valve 4 is connected to a two-way valve 11. Indoor heat exchanger12. Series circuit of two-way valve 13, three-way valve 2] Indoor heat exchanger 22. Series circuit of two-way valve 23, two-way valve 31. Indoor heat exchanger 32.
A series circuit of two-way valves 33 is connected to each other. These series circuits are connected in parallel with each other, and the parallel circuit is connected to the suction side of the compressor 1 via the four-way valve 2.

Connections from the expansion valve 4 to the indoor heat exchangers 12, 22, 23 are a liquid side main pipe Wo and liquid side branch pipes W, , W2. W
3, and its liquid side branch pipes W, , W2. W
, are provided with two-way valves 11, 21 and 31, respectively.

Connections from the indoor heat exchangers 12, 22, 32 to the four-way valve 2 are gas side branch pipes G, , G2. G, and gas side main pipe G
o, and its gas side branch pipes G, , G2 .
Two-way valves 1B and 23°33 are provided at G and G, respectively.

And two-way valve 11, 21.31 and indoor heat exchanger 12,
22.32 and the liquid side branch pipe W+, W2.

A bypass pipe 7 having capillary tubes 5, 5.5 and a capillary tube 6 is connected from W to the suction side piping of the compressor 1.

Note that the compressor 1, four-way valve 2, outdoor heat exchanger 3, expansion valve 4, two-way valves 11, 21 . '31, two-way valve 13.23,
33, bypass pipe 7, etc., the outdoor unit A
is configured.

In addition, at least the indoor heat exchanger 12 constitutes an indoor unit B, at least the indoor heat exchanger 22 constitutes an indoor unit B2, and at least the indoor heat exchanger 3 constitutes an indoor unit B.
2 constitutes an indoor unit B3.

Explain the action.

Heating operation mode and indoor temperature Ts in indoor unit B1
is set and the operation switch is turned on. Indoor unit B2. It is assumed that the operation switch is turned off in B3.

In this case, as shown in FIG. 4, the two-way valve 11.13 corresponding to the indoor unit B1 that is on is opened (displayed in white), and the indoor unit B2. Three-way valves 21, 23 and 31° 33 corresponding to B3 are closed (shown in black in the figure). Then, when the compressor 1 is turned on, the four-way valve 2 is switched.

Therefore, the refrigerant discharged from the compressor 1 passes through the four-way valve 2 and enters the indoor heat exchanger] 2 of the indoor unit B1, where the refrigerant loses heat to the indoor air and condenses. The refrigerant that has passed through the indoor heat exchanger 12 is depressurized by the expansion valve 4 and enters the outdoor heat exchanger 3, where the refrigerant is evaporated by the heat pumped up from the outside air. The refrigerant passing through the outdoor heat exchanger 3 passes through the four-way valve 2 and is sucked into the compressor 1.

During this heating operation, due to the suction pressure of the compressor 1, the refrigerant remaining in the indoor heat exchanger 22, 32 of the indoor unit I' B 2 + B 3, which is out of operation, is collected into the compressor 1 through the bypass pipe 7. Ru.

This refrigerant recovery prevents refrigerant from accumulating in an indoor unit that is not in operation, and in turn prevents an insufficient circulating amount of refrigerant in an indoor unit that is in operation.

(Problems to be Solved by the Invention) However, when one indoor unit is operated as described above, the amount of refrigerant circulated may become excessive due to refrigerant recovery. In this case, the high-pressure side pressure may rise abnormally, causing the high-pressure switch to operate, resulting in an unnecessary stoppage of operation.

Moreover, the refrigerant recovery tends to be a so-called liquid backlash, which adversely affects the life of the compressor 1.

This invention has been developed in consideration of the above circumstances, and its purpose is to prevent an abnormal rise in the pressure on the high pressure side during heating operation and to prevent liquid backflow to the compressor while the operation is stopped. An object of the present invention is to provide an air conditioner that can prevent refrigerant from accumulating in an indoor unit, can maintain an appropriate amount of refrigerant circulating in the indoor unit during operation, and can always operate stably. .

[Structure of the Invention] (Means for Solving the Problems) An outdoor unit having a variable capacity compressor, a four-way valve, an outdoor heat exchanger, and a pressure reducer, a plurality of indoor units having indoor heat exchangers, and the above-mentioned variable capacity compressor. A heat pump refrigeration cycle that connects a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, and a parallel circuit of each indoor heat exchanger, and multiple liquid side branch pipes between each of the indoor heat exchangers and the pressure reducer. A four-way valve controls the refrigerant discharged from the variable capacity compressor and a flow rate adjustment valve provided respectively.

Means for executing heating operation through each indoor heat exchanger, pressure reducer, and outdoor heat exchanger in this order, and controlling the capacity of the variable capacity compressor during heating operation according to the total required capacity of each indoor unit. means for controlling the opening degree of the flow rate regulating valve corresponding to the indoor heat exchanger of each indoor unit according to the required capacity of each indoor unit; and and means for opening a flow rate regulating valve corresponding to an indoor heat exchanger of a stopped indoor unit to a predetermined opening degree.

(Function) During heating operation, the amount of refrigerant flowing into the indoor heat exchanger of the indoor unit in operation is set according to the required capacity of the indoor unit.

At the same time, a predetermined amount of refrigerant flows through the indoor heat exchanger of the indoor unit that is not operating, so that the refrigerant does not accumulate in the indoor heat exchanger.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In the drawings, the same parts as in FIG. 3 are given the same reference numerals.

In FIG. 1, reference numeral 1' denotes a variable capacity compressor, and an outdoor heat exchanger 3 is connected to the discharge side of the variable capacity compressor 1' via a four-way valve 2. A pressure reducer such as an expansion valve 4 is connected to the outdoor heat exchanger 3, and a flow rate regulating valve (PM) is connected to the expansion valve 4.
V, pulse motor valve) 14 and indoor heat exchanger 1
2 series circuit, flow control valve 24 and indoor heat exchanger 22
A series circuit of the flow rate regulating valve 34 and an indoor heat exchanger 32 are connected to each other. These series circuits are connected in parallel to each other, and the parallel circuit is connected to the four-way valve 2.
It is connected to the suction side of the compressor 1 via.

The connection from the expansion valve 4 to the indoor heat exchanger 12, 22゜23 is the liquid side main pipe WO and the liquid side branch pipes W+, W2.
, W3, and its liquid side branch pipes W, , W2
．． Flow rate regulating valves 1424.34 are provided in W3, respectively.

The connection from the indoor heat exchangers 1.2, 22.32 to the four-way valve 2 is through the gas side branch pipe G1. G2, G3 and gas side main pipe Go.

And the flow rate regulating valve 14, 24, 34 and the indoor heat exchanger 1
2, 22.32 and the liquid side branch pipe W1°W2. To W3,
Refrigerant temperature sensors 15, 25, and 35 are installed, respectively.

A refrigerant pressure sensor 8 is attached to a high pressure side pipe between the discharge side of the variable capacity compressor 1' and the four-way valve 2.

Note that A is an outdoor unit, and Bl + B2 and B3 are indoor units.

The control circuit is shown in FIG.

Indoor unit B1. B2. B3 each has an indoor control section 40. An indoor temperature sensor 41 , an operation section 42 , and an indoor fan motor 43 are connected to the indoor control section 40 .

The indoor temperature sensor 41 detects the indoor temperature.

The operation unit 42 is for setting various operating conditions.

The indoor fan motor 43 is connected to the indoor heat exchanger 12°22.3
2 is a drive motor for an indoor fan that circulates indoor air.

The indoor control unit 40 includes a functional means for transmitting operating conditions set by the operation unit 42 to an outdoor control unit 50, which will be described later.
It is provided with functional means for transmitting the difference between the temperature detected by the indoor temperature sensor 41 and the indoor temperature set by the operating section 42 to the outdoor control section 50 as the required capacity.

On the other hand, the outdoor unit 50 includes an outdoor control section 50.

This outdoor control unit 50 includes a four-way valve 2 and the flow rate adjustment valve 14.
, 24, 34, temperature sensor 15°25.35, pressure sensor 8, inverter circuit 5], and outdoor fan motor 5
3 is connected.

The inverter circuit 51 rectifies the voltage of the commercial AC power supply 52, converts it into AC having a frequency (and voltage) according to a command from the outdoor control unit 50, and outputs the AC. The drive motor IM of the variable capacity compressor 1- is connected to the output end of the inverter circuit 5.

The outdoor fan motor 53 is a drive motor for an outdoor fan that circulates outside air to each of the outdoor heat exchangers 3 .

The outdoor control unit 50 controls the refrigerant discharged from the variable capacity compressor 1' to the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4,
Flow rate adjustment valves 14, 24, 34, indoor heat exchangers 12, 22
．． 32 in order, and the refrigerant discharged from the variable capacity compressor 1' to the four-way valve 2, the indoor heat exchanger 12, 22, 32, and the flow rate adjustment valves 14, 24, 3.
4. A functional means for performing heating operation through the expansion valve 4 and the outdoor heat exchanger 3 in this order, and an indoor unit during the heating operation.
A functional means for controlling the capacity of the variable capacity compressor 1' (output frequency of the inverter circuit 51) according to the sum of the required capacities of 1 r 82 r 83; A functional means that controls the opening degree of the flow rate adjustment valve corresponding to the indoor heat exchanger of each indoor unit according to the required capacity, and a flow rate adjustment that corresponds to the indoor heat exchanger of the indoor unit when the operation is stopped during heating operation. Open the valve to the specified degree (range where the degree of supercooling of the refrigerant is within the set value)
It is equipped with a functional means that opens to the front.

Next, the operation in the above configuration will be explained.

Assume that the heating operation mode and the indoor temperature Ts are set on the operating section 42 of the indoor unit B1, and the operation switch of the operating section 42 is turned on. Indoor unit B2. It is assumed that the operation switch on the operation unit 42 of B3 is turned off.

In this case, the variable capacity compressor 1' is activated, and its capacity is controlled according to the total required capacity of the indoor units B1+82r83. At the same time, the four-way valve 2 is switched.

Further, the flow rate regulating valve 14 corresponding to the indoor unit B that is in operation is opened, and its opening degree is controlled according to the required capacity of the indoor unit B1.

Therefore, as shown by the solid arrow in FIG. 1, the refrigerant discharged from the variable capacity compressor 1- flows into the indoor heat exchanger 12 through the four-way valve 2, where the refrigerant loses heat to the indoor air. and condense it. The refrigerant that has passed through the indoor heat exchanger 12 flows into the outdoor heat exchanger 3 through the flow rate adjustment valve 14 and the expansion valve 4, where the refrigerant absorbs heat from the outside air and evaporates. The refrigerant that has passed through the outdoor heat exchanger 3 passes through the four-way valve 2 and is sucked into the variable capacity compressor 1'. Then, the indoor fan of the indoor unit B1 is turned on and the indoor air is circulated through the indoor heat exchanger 12, so that the indoor fan of the indoor unit B1
heating operation is executed.

The conditions shown in the table on the next page are predetermined between the required capacity of the indoor unit when the operation is on and the opening degree (drive pulse number) of the flow rate adjustment valve based on it, and the larger the required capacity, the lower the opening degree. is set large.

Note that the opening degrees shown in this table are values determined through experiments so that the degree of supercooling of the refrigerant in the indoor heat exchanger is approximately 5°C.

In addition, at the same time as the start of operation, indoor unit B2, which is turned off,
．． The flow rate regulating valves 24 and 34 corresponding to B3 are first opened to minute openings corresponding to 10 pulses.

That is, as shown by the broken line arrow in FIG. 1, a part of the refrigerant discharged from the variable capacity compressor 1' and passed through the four-way valve 2 passes through the indoor heat exchanger 22.32 and the flow rate adjustment valve 24.34. It joins the flow of refrigerant to the expansion valve 4.

In addition, indoor unit B2. The indoor fan in B3 is turned off.

Based on the high pressure side pressure detected by the refrigerant pressure sensor 8, the condensation temperature Tc of the refrigerant in the indoor heat exchanger 22.32 is determined.
are required respectively.

The above condensation temperature Tc and the detection temperature T2 of the refrigerant temperature sensor 25
The difference is calculated, and the calculation result is detected as the degree of subcooling UC2 of the refrigerant in the indoor heat exchanger 22. Then, the opening degree of the flow rate regulating valve 24 is controlled so that the degree of supercooling UC2 is within a predetermined range, for example, 5°C.

The above condensation temperature Tc and the detection temperature T3 of the refrigerant temperature sensor 35
The difference is calculated, and the calculation result is detected as the degree of subcooling UC of the refrigerant in the indoor heat exchanger 32. Then, the opening degree of the flow rate regulating valve 34 is controlled so that the degree of supercooling UC3 is within a predetermined range, for example, 5°C.

The opening degree control of the flow rate regulating valve corresponding to the indoor unit whose operation is stopped is performed as follows.

A sampling time of a certain period of time, for example 30 seconds, is determined in advance, and the degree of supercooling is detected each time the sampling time comes around.

The value of the degree of supercooling UCn detected in the current sampling and the degree of supercooling U Cn− detected in the previous sampling.
The difference from 1 (-U Cn -U Cn-1) is calculated,
The proportional correction value P is determined from the difference and the conditions shown in the table on the next page.

The difference between the value of the supercooling degree UCn detected in the current sampling and the set supercooling degree UCs (-5°C) (=UCn −
UCs ) is determined, and the integral correction value I is determined from the difference therebetween and the conditions in the table shown on the next page.

The sum of the obtained proportional correction value P and integral correction value I is calculated as the opening correction value ΔPLS, and the opening correction value ΔP
The opening degree of the flow rate adjustment valve is corrected by LS.

ΔPLS-P+1 In this way, a predetermined amount of refrigerant flows through the indoor heat exchangers 22, 32 of the indoor units B2+B3 that are not in operation, so that the refrigerant does not accumulate in the indoor heat exchangers 22, 32. In this case, an abnormal increase in the pressure on the high pressure side does not occur, and no liquid backflow to the variable capacity compressor 1' occurs.

Since the refrigerant does not accumulate, insufficient refrigerant circulation in the indoor unit B1 is prevented, and stable heating operation is performed.

Although the above embodiment describes the operation of one indoor unit, the same control is performed regardless of the number of indoor units in operation.

Further, in the above embodiment, the case where the number of indoor units is three has been described, but the number is not limited.

[Effect of the invention] As described above, according to the present invention, a variable capacity compressor,
An outdoor unit having a four-way valve, an outdoor heat exchanger, and a pressure reducer; a plurality of indoor units having an indoor heat exchanger; and the variable capacity compressor, four-way valve, outdoor heat exchanger, pressure reducer, and each indoor heat exchanger. A heat pump type refrigeration cycle connected in parallel circuits, a flow rate adjustment valve provided in each of the plurality of liquid side branch pipes between each of the indoor heat exchangers and the pressure reducer, and refrigerant discharged from the variable capacity compressor. means for performing heating operation through a four-way valve, each indoor heat exchanger, a pressure reducer, and an outdoor heat exchanger in this order, and the variable capacity compressor according to the total required capacity of each indoor unit during heating operation. means for controlling the capacity of the indoor heat exchanger of each indoor unit during heating operation according to the required capacity of each of the indoor units; , is equipped with a means to open the flow rate regulating valve corresponding to the indoor heat exchanger of the indoor unit that is out of operation to a predetermined opening degree, so that there is no abnormal increase in the pressure on the high pressure side during heating operation, and the flow to the compressor is prevented. It is possible to prevent refrigerant from accumulating in the indoor unit when the unit is not in operation without causing liquid back-up, and it is possible to maintain the appropriate amount of refrigerant circulation in the indoor unit when the unit is in operation, ensuring stable operation at all times. We can provide air conditioners that

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a refrigeration cycle according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a control circuit of the same embodiment, and FIG. 3 is a diagram showing the configuration of a refrigeration cycle of a conventional air conditioner. The diagram shown in FIG. 4 is a diagram for explaining the flow of refrigerant in the refrigeration cycle of FIG. 3. A...Outdoor unit, B1. B2. B3...Indoor unit, 1'...Variable capacity compressor, 2...Four-way valve,
3... Outdoor heat exchanger, 4... Expansion valve (pressure reducer), 1
222.32...Indoor heat exchanger, 14,24.34.
...Flow rate adjustment valve, 15, 25.35... Refrigerant temperature sensor, 40... Indoor control section, 50... Outdoor control section.

Claims (1)

[Claims] an outdoor unit having a variable capacity compressor, a four-way valve, an outdoor heat exchanger, and a pressure reducer; a plurality of indoor units having indoor heat exchangers; the variable capacity compressor, four-way valve, outdoor heat exchanger, and pressure reducer; A heat pump type refrigeration cycle to which parallel circuits of each indoor heat exchanger are connected, a flow rate adjustment valve provided in each of a plurality of liquid side branch pipes between each of the indoor heat exchangers and the pressure reducer, and the variable capacity compressor. A means for performing heating operation by passing refrigerant discharged from the four-way valve, each indoor heat exchanger, a pressure reducer, and an outdoor heat exchanger in this order; Means for controlling the capacity of the variable capacity compressor, and means for controlling the opening degree of the flow rate regulating valve corresponding to the indoor heat exchanger of each indoor unit according to the required capacity of each indoor unit during heating operation. and means for opening a flow rate regulating valve corresponding to an indoor heat exchanger of an indoor unit that is stopped to a predetermined opening degree during heating operation.