JPH0336473A - Air conditioner - Google Patents

Abstract

PURPOSE:To carry out proper capacity control over a wide range and hence enable comfortable heating constantly by using selectively each outdoor heat exchanger in compliance with the difference between the quantity of heat absorption on a cooling side and the quantity of heat discharge on a heating side of each indoor unit during the simultaneous operations both heating and cooling of each indoor unit. CONSTITUTION:When cooling operation mode is preset with indoor units C1 and C2 and heating operation mode is set with an indoor unit C3, solenoid on/off valves 2, 15, 25, and 34 are opened while solenoid on/off valves 7, 14, 24, and 35 are closed. Furthermore, solenoid valves 91, and 92 are opened while a solenoid valve 94 is closed. Then, in addition to an outdoor heat exchanger 3a, an outdoor heat exchanger 3b is throw in. The condensation pressure equivalent to the difference between the quantity of heat absorption on a cooling side and the quantity of heat discharge on a heating side of each indoor heat exchanger is detected with a refrigerant pressure sensor 95 and the detected value is compared with a preset value. If the detected condensation value is lower than the preset value, the rotary speed of an outdoor fan 8 is gradually reduced. However, when the outdoor fan 8 comes to a halt, the throwing in of the outdoor heat exchanger 3b is canceled.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a multi-type air conditioner having a plurality of indoor units.

(Prior Art) Generally, as a multi-type air conditioner having a plurality of indoor units, there is one in which each indoor unit can perform cooling operation and heating operation simultaneously. - An example is shown in FIG.

A is an outdoor unit, and a plurality of indoor units C, )C2, c,
are connected. These outdoor units A1, refrigerant switching unit B, and indoor units cl, c2. c・
3, the following refrigeration cycle is constructed.

A variable capacity compressor 1, an electromagnetic on-off valve 2, an outdoor heat exchanger 3, a parallel body of a heating expansion valve 4 and a cooling cycle forming check valve 5,
Liquid tank 6, parallel body of cooling expansion valve 11.21.31 and heating cycle forming check valve 12.22.32, indoor heat exchanger 13.23.33 of each indoor unit, electromagnetic flow direction switching On-off valve 14°24.34 and 15.2
5°35 are connected in sequence to form a heat pump type refrigeration cycle.

Note that the communication portion between the electromagnetic on-off valve 2 and the outdoor heat exchanger 3 is communicated with the suction side of the compressor 1 via the electromagnetic on-off valve 7. Furthermore, an outdoor fan 8 is provided near the outdoor heat exchanger 3.

Furthermore, the outdoor unit A includes an outdoor control section 40. The outdoor control unit 40 is composed of a microcomputer and its peripheral circuits, and includes an inverter circuit (not shown) for driving the compressor, electromagnetic on-off valves 2 and 7, and an outdoor fan 8.
control.

The refrigerant switching unit B includes a multi-control unit 50. This multi-control unit 50 consists of a microcomputer and its peripheral circuits, and includes electromagnetic on-off valves 14, 24, 34.
and control 15, 25.35.

Indoor unit c, , C2+ CB is indoor control unit 6
It is equipped with 0.70.80. These indoor control units consist of a microcomputer and its peripheral circuits.

Then, in the outdoor control section 40, the multi-control section 50, and the indoor control sections 60, 70.80, the indoor unit C1
* C2 * Functional means that controls each electromagnetic on-off valve according to the required operation mode of C3 and switches the refrigerant flow direction to each indoor unit, and indoor units C, + C2+
Function means for controlling the operating frequency of the compressor 1 (output frequency of the inverter circuit) according to the total required capacity of the compressor C3.

That is, when the cooling operation mode is set in all indoor units, the electromagnetic on-off valves 2, 15, 25.35 are opened, and the electromagnetic on-off valves 7, 14 are opened, as shown in black and white in FIG. , 24, and 34 are closed, and the refrigerant is allowed to flow in the direction of the solid arrow, so that the outdoor heat exchanger 3 acts as a condenser, and all the indoor heat exchangers 13, 23, and 33 act as evaporators.

In this case, the amount of heat absorbed by the indoor heat exchanger 13, 23.33 Q
The sum of cool and the equivalent heat amount Q comp of input to the compressor corresponds to the heat radiation amount Q of the outdoor heat exchanger 3.

Furthermore, when the cooling operation mode is set in the indoor units C1+C2 and the heating operation mode is set in the indoor unit C3, the electromagnetic on-off valves 2,
15.25.34 is opened, and the electromagnetic on-off valves 7, 14,
24 and 35 are closed, and the refrigerant is made to flow in the direction of the solid arrow shown in the figure, so that the outdoor heat exchanger 3 acts as a condenser, the indoor heat exchangers 13 and 23 act as an evaporator, and the indoor heat exchanger 33 acts as a condenser.

In this case, indoor unit c1. If the required cooling capacity of c2 is greater than the required heating capacity of indoor unit C3,
The compressor 1 is operated at a capacity to ensure the required cooling capacity. Then, the amount of heat absorbed by the indoor heat exchanger 13.23 Q co
The sum of ol and the equivalent heat amount Q comp of the compressor input corresponds to the sum of the heat radiation amount Q heat of the indoor heat exchanger 33 and the heat radiation amount Q of the outdoor heat exchanger 3.

(Problem to be Solved by the Invention) In such an air conditioner, when cooling operation and heating operation are mixed in each indoor unit, the outdoor heat exchanger 3 adjusts the amount of heat absorbed by the indoor unit on the cooling side and the amount of heat absorbed by the indoor unit on the heating side. It works to absorb the difference in heat dissipation.

However, the outdoor heat exchanger 3 is selected to have a capacity suitable for the load of cooling all rooms or heating all rooms.

For this reason, when the difference between the amount of heat absorbed on the cooling side and the amount of heat radiated on the heating side is small, a situation arises in which the amount of heat exchanged by the outdoor heat exchanger 3 becomes too large. When this happens, the condensing pressure drops and the condensing temperature drops below the room temperature, making it impossible to warm the room.

This invention was made in view of the above circumstances,
The purpose of this is to create an air conditioner that can perform appropriate capacity control over a wide range, regardless of the amount of heat absorbed on the cooling side and the amount of heat absorbed on the heating side of each indoor heat exchanger, and that always enables comfortable heating and cooling. Our goal is to provide the following.

[Structure of the Invention] (Means for Solving the Problems) An outdoor unit having a plurality of outdoor heat exchangers, a plurality of indoor units having an indoor heat exchanger, and each indoor unit having the same function according to the required operation mode of these indoor units. means for switching the refrigerant flow direction to the indoor unit; and a means for selectively controlling each of the outdoor heat exchangers according to the difference between the amount of heat absorbed on the cooling side and the amount of heat radiated on the heating side of each indoor unit when cooling and heating each of the indoor units at the same time. and a means for inputting.

(Function) The amount of outdoor heat exchange changes depending on the difference between the amount of heat absorbed on the cooling side and the amount of heat radiated on the heating side of each indoor unit.

(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. 6 are designated by the same reference numerals, and their explanations will be omitted.

As shown in FIG. 1, the outdoor heat exchanger 3 of the outdoor unit A
is divided into 3a and 3b.

Then, the outdoor heat exchanger 3a, the electromagnetic on-off valve 91, the outdoor heat exchanger 3b, and the electromagnetic on-off valve 92 are connected in series to the mutual communication portion of the electromagnetic on-off valves 2 and 7 and the mutual communication portion of the expansion valve 4 and check valve 5. Insert between the connecting part and the connecting part.

A bypass pipe 93 is connected in parallel to the series body of the electromagnetic on-off valve 91, the outdoor heat exchanger 3b, and the electromagnetic on-off valve 92,
An electromagnetic on-off valve 94 is provided in the bypass pipe 93.

Furthermore, a refrigerant pressure sensor 95 is attached to the connecting pipe between the mutual communication portion of the electromagnetic on-off valve 2.7 and the outdoor heat exchanger 3a.

The outdoor control section 40 of the outdoor unit A controls an inverter circuit (not shown) for driving the compressor, the electromagnetic on-off valves 2 and 7, the outdoor fan 8, and the electromagnetic on-off valves 91, 92, and 93.

Then, in the outdoor control section 40, the multi-control section 50, and the indoor control section 60, 70, 80, the indoor unit c,
, C21c, and a functional means for controlling each electromagnetic on-off valve and switching the refrigerant flow direction to each indoor unit according to the required operation mode of C21C3. Each electromagnetic on-off valve is controlled according to the detected pressure of the refrigerant pressure sensor 95 corresponding to the difference between the heat absorption amount and the heating side heat absorption amount, and the outdoor heat exchanger 3
a.

3b and the indoor unit C1.
The compressor 1 is provided with functional means for controlling the operating frequency of the compressor 1 (the output frequency of the inverter circuit) according to the sum of the required capacities of the compressor 1C2 and C3.

Next, the operation of the above configuration will be explained with reference to FIG. 2.

--When the cooling operation mode is set in the indoor units C1+C2 and the heating operation mode is set in the indoor unit C3, the electromagnetic on-off valves 2, 15, 25, and 34 are activated as shown in black and white in Figure 1. Open and solenoid on-off valve 7.1
4. Close 24.35. Furthermore, the electromagnetic on-off valve 91.
92 is opened, and the electromagnetic on-off valve 94 is closed to turn on the outdoor heat exchanger 3b in addition to the outdoor heat exchanger 3a.

That is, by flowing the refrigerant in the direction of the solid arrow shown in the figure, the outdoor heat exchangers 3a and 3b act as a condenser, the indoor heat exchangers 13 and 23 act as an evaporator, and the indoor heat exchanger 33 acts as a condenser.

Here, the amount of heat absorbed by the indoor heat exchanger 13.23 on the cooling side Q
Heating side heat radiation fiQh by cool and indoor heat exchanger 33
If the difference from ``eat'' is small (or if the outdoor temperature is too low), a situation arises in which the outdoor heat exchange amount Q becomes too large. When this happens, the condensing pressure drops and the condensing temperature drops below the room temperature, making it impossible to warm the room.

On the other hand, in order to ensure sufficient heating capacity in the indoor unit C3, assuming that the temperature of the room where the indoor unit C3 is installed is 21°C, the condensing temperature must be set to 50°C.
It is necessary to maintain

For this purpose, the condensing pressure must be maintained at 19) cg/cdG.

Therefore, the condensing pressure P corresponding to the difference between the amount of heat absorbed on the cooling side Qcool and the amount of heat released on the heating side Qheat of each indoor heat exchanger
is detected by the refrigerant pressure sensor 95, and the detected condensation pressure P
and a set value Po (here, 19 kg/cjG). If the detected condensation pressure P is lower than the set value Po (P<Po), the rotation speed of the outdoor fan 8 is gradually lowered one step at a time. If the detected condensation pressure P exceeds the set value Po (P>Po), the rotation speed of the outdoor fan 8 is gradually increased one step at a time. In this way, the detected condensation pressure P is maintained at the set value PO.

However, the outdoor fan 8 may stop before the detected condensation pressure P exceeds the set value Po.

In this case, as shown in FIG. 4, the electromagnetic on-off valve 94 is opened, the electromagnetic on-off valves 91 and 92 are closed, and the outdoor heat exchanger 3b is turned off.

When this outdoor heat exchanger 3b is not used, the detected condensing pressure P
If exceeds the set value Po, the outdoor fan 8
Although the rotation speed of the outdoor fan 8 is gradually increased one step at a time, the outdoor fan 8 may reach full speed (maximum rotation speed). In this case, the electromagnetic on-off valves 91 and 92 are opened, the electromagnetic on-off valve 94 is closed, and the outdoor heat exchanger 3b is turned on again.

By the way, the heat exchanger performance (heat radiation performance) of the outdoor heat exchangers 3a and 3b is determined based on the conditions shown in FIG.

In other words, the heat exchanger performance (Q2) of both the outdoor heat exchangers 3a and 3b when the outdoor fan 8 is stopped is higher than the heat exchanger performance (Q2) of only the outdoor heat exchanger 3b when the outdoor fan 8 is operating at full speed. In order to increase heat exchanger performance (Q3),
Outdoor heat exchanger 3a.

The capacity is set at 3b.

In this way, the cooling side heat absorption amount Qcool of each indoor heat exchanger
The condensing pressure P corresponding to the difference between
) By selectively turning on the outdoor heat exchangers 3a and 3b, appropriate capacity control can be performed over a wide range, and comfortable heating and cooling can be performed at all times.

Moreover, since the rotation speed control of the outdoor fan 8 is taken into account when selecting and turning on the outdoor heat exchangers 3a and 3b, the capacity change becomes smooth and comfort can be improved.

In the above embodiment, the communication part between the outdoor heat exchanger 3a and the electromagnetic on-off valve 92 is connected to the suction side of the compressor 1 by a pipe 96, and the electromagnetic on-off valve 97 and a capillary tube 98 are further provided in the pipe 96. The electromagnetic on-off valve 97 may be opened when the outdoor heat exchanger 3b is not in use. By doing so, the refrigerant remaining in the outdoor heat exchanger 3b can be recovered to the compressor 1, and stagnation of the refrigerant can be prevented.

Furthermore, in the above embodiments, the number of outdoor heat exchangers and the number of indoor units are not limited and can be set as appropriate.

In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without changing the gist.

[Effects of the Invention] As described above, according to the present invention, an outdoor unit having a plurality of outdoor heat exchangers, a plurality of indoor units having an indoor heat exchanger, and the required operation mode of these indoor units can be adjusted. means for switching the refrigerant flow direction for each indoor unit according to the difference between the amount of heat absorbed on the cooling side and the amount of heat radiated on the heating side of each indoor unit when cooling and heating each of the indoor units simultaneously; As a result, regardless of the magnitude of the heat absorption amount on the cooling side and the heat absorption amount on the heating side of each indoor heat exchanger, appropriate capacity control can be performed over a wide range, ensuring comfortable heating and cooling at all times. We can provide air conditioners that make it possible.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of the embodiment.
Figure s3 is a diagram showing the capacity setting conditions of each outdoor heat exchanger in the same example, and Figure 4 is a diagram for explaining the refrigerant flow when one outdoor heat exchanger is not used in the same example. FIG. 5 is a diagram showing the configuration of a modified example of the same embodiment, FIG. 6 is a diagram showing the configuration of a conventional air conditioner, and FIG. 7 is a diagram showing a state in which the refrigerant flow direction is switched in FIG. 6. . A...Outdoor unit, B...Refrigerant switching unit, c
, l C2r c3... Indoor unit, 1...
Variable capacity compressor, 3a, 3b... outdoor heat exchanger, 40
...Outdoor control section, 50...Multi control section, 60,7
0.80...Indoor control unit.

Claims (1)

[Claims] an outdoor unit having a plurality of outdoor heat exchangers; a plurality of indoor units having an indoor heat exchanger; means for switching a refrigerant flow direction to each indoor unit according to a required operation mode of these indoor units; An air conditioner characterized by comprising means for selectively turning on each of the outdoor heat exchangers according to the difference between the amount of heat absorbed on the cooling side and the amount of heat radiated on the heating side of each indoor unit when cooling and heating the unit simultaneously operate. Machine.