JPH02217737A - Air conditioner - Google Patents

Abstract

PURPOSE:To increase the quantity of refrigerant circulating through indoor equipment which calls for a large air conditioning capacity by providing an air capacity change means which reduces a rotary speed of an indoor fan for said indoor equipment in a small room where a detected air conditioning load is smaller than the average load. CONSTITUTION:A plurality of indoor equipment from A to D are connected with one air conditioner X in parallel with each other. The air conditioner is provided with a flow rate control means 19 which carried out superheat degree control or supercooling degree control for the quantity of refrigerant circulating in each indoor equipment from A to D respectively, an air conditioning load detection means 33, and an average load computing means 41, which calculates the average load. An air capacity change means 42 lowers the rotary speed of an indoor fan 25 in the indoor equipment in a room where a detected air conditioning load is smaller than the average detected air conditioning load per room. More specifically, the quantity of refrigerant circulating in the indoor equipment is reduced by the flow rate control means 19 so that it may be equivalent to the quantity of heat exchange of the air capacity in proportion to the reduction in the air capacity. Which results in an increase in the flow rate of the indoor equipment for the other room where detected air conditioning load is larger than the average value. Therefore, the air conditioning capacity of the indoor equipment can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-type air conditioner configured by connecting a plurality of indoor units to one outdoor unit.

(Prior Art) As a conventional example of the multi-type air conditioner as described above, for example, a device described in Japanese Patent Application Laid-Open No. 63-220032 can be cited. In this system, a plurality of branch refrigerant pipes each having an electric expansion valve are installed in a single outdoor unit having a compressor and an outdoor heat exchanger, and each of these branch refrigerant pipes is connected to an indoor heat exchanger. It has a configuration in which indoor units each having an exchanger are connected in parallel with each other. In such a device, for example, during cooling operation, the degree of superheating of the evaporative refrigerant in each indoor heat exchanger is maintained at the reference degree of superheat by controlling the opening degree of each electric expansion valve. The amount of circulating refrigerant is adjusted.

The above-mentioned indoor unit has a standard air conditioning capacity (hereinafter referred to as capacity) determined by the heat transfer coefficient, heat transfer area, passing wind speed, etc. of the indoor heat exchanger installed, for example, 2000 yen.
．． 2500.2800.3500.4500...kc
From models that vary in stages such as al/h, a model is selected for each room according to the indoor air conditioning load level estimated based on the size of the installation room, the wall insulation structure, etc.

By the way, for example, as an indoor unit for two rooms, room A with a load level of 2300 kcal/h and room B with a load level of 3700 kcal/h, the capacity 25 that is closest to each load level is
00. When selecting a model with a capacity of 3500kcal/h, when each indoor unit is operated independently, the capacity in room A is within the range of 2500kcal/h, and the capacity in room B is slightly over 3500kcal/h. Within the range, operation is performed at an air conditioning capacity corresponding to each negative A'+:jL Bell.

However, when both indoor units are operated at the same time, the amount of circulating refrigerant to each indoor unit is distributed according to the capacity ratio. If the room is operated with the air conditioning capacity, a problem arises in that the operating state in which the air conditioning capacity on the B room side is insufficient continues. For this reason, conventionally, even if an indoor unit with a capacity that is suitable for the load level in each room is selected, if there is an excess or deficiency in air conditioning capacity during simultaneous operation, the indoor unit with the insufficient capacity is replaced with a capacity one class higher. In the case of room B above, 4500kca
A model of 1/h is selected so as not to cause insufficient capacity for each load level, so that, for example, quick heating performance at the start of heating operation is not impaired.

(Problem to be Solved by the Invention) By the way, in order to prevent a lack of capacity during simultaneous operation as described above, it is necessary to select a model one class higher as the indoor unit for the room where the capacity is insufficient. For example, an installation situation occurs in which the total capacity of the indoor units is excessive with respect to the total load level on the indoor side, resulting in a problem that, for example, the installation cost becomes high.

This invention was made in view of the above, and its purpose is to enable operation that is more suited to the indoor load level without selecting a model with an excessive capacity, and as a result,
An object of the present invention is to provide an air conditioner whose installation cost can be reduced compared to conventional ones.

(Means for Solving the Problem) Therefore, the air conditioner of the present invention connects a plurality of indoor units A to D in parallel to one outdoor unit X, and circulates through each indoor unit A to D. An air conditioner comprising flow rate control means 19 for controlling the degree of superheating or supercooling of the amount of refrigerant, and as shown in FIG. 1, air conditioning load detection means for detecting the air conditioning load in each room. 33, an average load calculation means 41 that calculates the average of the detected air conditioning loads in each room, and an air volume that reduces the rotation speed of the indoor fan 25 in the indoor unit A in the room where the detected air conditioning load is smaller than the average load. A changing means 42 is provided.

(Function) In the above air conditioner, the rotation of the indoor fan 25 in the indoor unit in a room where the detected air conditioning load detected as the difference between the set room temperature and the detected room temperature is smaller than the average of the detected air conditioning loads for each room. By reducing the speed, that is, reducing the air volume, the amount of refrigerant circulating through the indoor unit is adjusted to an amount commensurate with the amount of heat exchanged with the reduced air volume.
is reduced by As a result, the flow rate to the indoor units in other rooms whose detected air conditioning load is larger than the above average increases, and the air conditioning capacity of these indoor units increases. In other words, in the above case, the detected air conditioning load is smaller than the average and the amount of circulating refrigerant to the indoor unit that no longer requires large air conditioning capacity is reduced, and the detected air conditioning load is larger than the average and therefore requires larger air conditioning capacity. The circulating refrigerant is distributed to increase the amount of circulating refrigerant to the indoor unit. As a result, even if an indoor unit with a capacity that is slightly lower than the load level is installed in one room as a result of selecting an indoor unit with a capacity that is more suitable for the load level of each room, it is possible to When the detected air conditioning load becomes small, the amount of refrigerant circulated to the indoor unit is increased, that is, the air conditioning capacity is increased, and the insufficient air conditioning capacity is resolved. Therefore, it is possible to maintain operation with as little deterioration of air conditioning comfort as possible even when selecting indoor units with capacities that suit the load level of each room. It becomes possible to reduce the size, and as a result, installation costs can be reduced.

(Example) Next, regarding a specific example of the air conditioner of this invention,
This will be explained in detail with reference to the drawings.

First, Fig. 2 shows a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention. In the figure, X is an outdoor unit, and this outdoor unit X has four indoor units A- D is connected.

A compressor 1 is installed in the outdoor unit Pipe 5 and second gas pipe 6 are connected. The compressor 1 has an inverter 7 for controlling its rotational speed, that is, its compression capacity.1. Further, a check valve 8 is provided in the discharge pipe 2, and an akinimulator 9 is provided in the suction pipe 3.

The first gas pipe 5 is connected to an outdoor heat exchanger 10, and the second gas pipe 6 is connected to a header 11, and a gas shutoff valve 12 is interposed therebetween. An outdoor fan 13 is attached to the outdoor heat exchanger 10, and a liquid pipe 14 is also connected to the liquid pipe 14. A dryer filter 15, a first electric expansion A valve 16, a liquid receiver 17, and a liquid shutoff valve 18 are provided. The tip of the liquid pipe 14 is branched into a plurality of (four in the case of the figure) liquid branch pipes 20...20 each having a second electric expansion valve (flow rate control means) 19...19 interposed therein. On the other hand, a muffler 21 and a muffler 21 are attached to the header 11, respectively.
・Four gas branch pipes 22 with 21 interposed therein are connected, and these gas branch pipes 22 and each of the liquid branch pipes 20 are connected to each other.
Indoor heat exchangers 23 (only the indoor unit A is shown) installed in each of the indoor units A and -D are connected between them by connecting pipes 24, . . . , 24, respectively. Note that an indoor fan 25 is attached to each indoor heat exchanger 23 in each of the indoor units A to D.

For heating operation in the air conditioner configured as described above, the four-way switching valve 4 is located at the switching position shown by the solid line in the figure, and the refrigerant discharged from the compressor 1 is routed from the second gas pipe 6 to each indoor heat exchanger 23. The gas is supplied and condensed, then passed through the liquid pipe 14 and evaporated in the outdoor heat exchanger IO, and then returned to the compressor 1 from the first gas pipe 5. In this case, the degree of superheating of the evaporative refrigerant is controlled by the first electric expansion valve 6, and each second electric expansion valve 19 controls the degree of supercooling of the condensed refrigerant in each indoor heat exchanger 23. Each indoor heat exchanger 2
Controls the amount of refrigerant distributed to 3. The second electric expansion valve 19 corresponding to the indoor unit A in the room where the operation is stopped is at the stop opening (
The opening should be set to allow a small amount of refrigerant to flow, commensurate with natural heat dissipation.

On the other hand, cooling operation is performed by switching the four-way switching valve 4 to the switching position shown by the broken line in the figure and circulating the refrigerant discharged from the compressor 1 from the outdoor heat exchanger 10 side to each indoor heat exchanger 23. . At this time, the first electric expansion valve 16 is fully opened,
Each second electric expansion valve 19 controls the degree of superheating of the refrigerant. The second electric expansion valve 19 corresponding to the indoor unit A in the room where cooling is stopped is fully opened.

Next, control of the operation of the air conditioner will be described with reference to the operation control system diagram in FIG. 3, taking heating operation as an example. As shown in the figure, each of the indoor units A to D is equipped with an indoor control device 31 (only the indoor unit A is shown), and each indoor control device 31 includes a remote controller 32 for operation and a room temperature sensor for detecting the room temperature. A sensor (air conditioning load detection means) 33 is connected respectively. Each of the operation remote controllers 32 has an operation switch and a temperature setting switch for setting a desired room temperature, and when the operation switch is ON and the room temperature detected by the room temperature sensor 33 reaches the set room temperature. When the indoor thermostat is not on (when the indoor thermostat is ON), an operation request signal is output from each indoor control device 31 to the outdoor unit X together with a temperature difference signal ΔD between the detected room temperature and the set room temperature, and the indoor control device 31 operates the indoor fan 25.

On the other hand, the outdoor unit X includes an outdoor control device 35 and an inverter control device 36, and the outdoor control device 35 includes:
A frequency control section 37 and a valve control section 38 are provided.

First, the valve control unit 3 positions the four-way switching valve 4 in the heating operation switching position in response to the operation request signal from each of the indoor units A to D, and during the heating operation, the first electric Superheat degree control of expansion valve 16, each second electric expansion valve 19
The degree of supercooling is controlled.

On the other hand, the frequency control section 37 calculates the total capacity of each indoor unit with an operation request, and further extracts the maximum temperature difference among the temperature difference signals ΔD from each indoor unit with an operation request.

Next, an initial frequency corresponding to the combination of the above total capacity and maximum temperature difference is selected from a data table of initial frequencies preset for various combinations of capacity and temperature difference, and this is selected from the data table of initial frequencies set in advance for various combinations of capacity and temperature difference. Output to 36.

As a result, the inverter control device 36 starts driving the compressor 1 at the initial frequency, and after the rotation speed has reached the initial frequency, the inverter control device 36 starts to drive the compressor 1 at the initial frequency. A corresponding frequency, for example, by PMD control, is sequentially generated in the frequency control section 37, and the heating operation is continued while controlling the compression capacity of the compressor 1 at this frequency. Note that if the number of operating rooms increases or decreases, the above-mentioned procedure is newly repeated starting from the control for selecting the initial frequency. As the heating operation controlled in this manner continues, the indoor temperature gradually rises, and the air conditioning load in each room, that is, the temperature difference ΔD approaches O, and operation continues to maintain this temperature difference ΔD at approximately O. be done.

By the way, for example, the air conditioning load level in room A is 2300kc.
al/h Air conditioning load level of SB room is 3700kca
l/h, the indoor unit ASB of each room is the capacity 2500.3500 that is closest to the respective load level.
When a kcal/h model is installed, for example, when both indoor units A and B start heating operation at the same time, the temperature difference ΔD at the beginning of operation is large, and as a result, indoor unit A , B total capacity 6000kcal
/h is set as the initial frequency, and operation of the compressor 1 is started at this frequency. Therefore, the compressor 1 discharges an amount of refrigerant that can provide an air conditioning capacity comparable to the total capacity of both indoor units A and B, and is distributed to each indoor unit A and B approximately according to their capacity ratio. .

As a result, on the A room side, the load level is 2300kcal/
The room B side is operated at an air conditioning capacity slightly higher than the load level of 3,700 kcal/h. For this reason, in the past, although a quick rise in room temperature was achieved in room A, the air conditioning capacity in room B was small compared to the indoor load level, so the speed of rise in room temperature was slow and rapid heating was not achieved. It had become a thing. Therefore, in the above embodiment, as shown in FIG. 3, an air conditioning load monitoring control section 39 is further provided in the outdoor control device 35.
It is designed to improve the heating speed on the side where the capacity is insufficient as described above, and the control performed by the air conditioning load monitoring control section 39 will be described below with reference to the control flowchart of FIG. 4. In the following explanation, each of the indoor fans 25 described above can have four rotational speeds, from strong wind (H), which provides the maximum air volume, to medium wind (M), weak wind (L), and light wind ( It is assumed that four fan taps up to LL are provided, and one of the fan taps is selected by the indoor control device 31 to operate at each of the above-mentioned air volumes.

Step S1 in FIG. 4 is a step of reading the temperature differences ΔDi sent from the indoor units A, etc. that are in operation, and then, in step S2, the total ΣΔDi of the temperature differences ΔDi read above is calculated. The average temperature difference, that is, the average load ΔDmean, is calculated by dividing this by the number n of indoor units in operation. Then, in step S3, a room m whose ΔDi is smaller than the average load ΔD mean is extracted. Furthermore, in step S4,
The temperature difference Δh+ in room m is compared with a predetermined reference temperature difference Δh+, and if 60 m is smaller than Δh+, in step S5, the indoor control device 31 of the indoor unit in room m is A command to reduce the rotational speed of the indoor fan 25 is output. Due to this lowering command, for example, if the indoor fan 25 was operated in strong wind (H) until then,
Rather than this, the indoor control device 31 switches the fan tap to His Royal Highness's medium wind (M), thereby reducing the amount of air passing through the indoor heat exchanger 23.

After the process in step S5 is completed, or in step S4
If the determination result is that ΔDn+ is greater than or equal to ΔKan, the process returns to step S1, and the process from step 31 onward is repeated at a predetermined time interval.

The results of the above control will be explained by taking as an example a case where the heating operation is started in room A and room B at the same time with the indoor fans 25 set to strong wind (H). As a result, the temperature difference ΔDa on the A room side is larger than that on the B room side as a result of continued operation at room A side with an air conditioning capacity higher than the load level and room B side with an air conditioning capacity lower than the load level. The temperature difference ΔDb becomes smaller faster than the temperature difference ΔDb, and therefore the room m where ΔDi is smaller than the average load ΔD mean
Therefore, the temperature difference ΔD on the A room side is
a is compared with a reference temperature difference ΔDr. And ΔDa is Δ
When the temperature becomes smaller than Dr, that is, when the room temperature in room A rises to near the set room temperature, the rotation speed of the indoor fan 25 in indoor unit A in room A changes from strong wind ([■) to moderate wind ().
M). As a result, the amount of air passing through the indoor unit A decreases, and therefore the amount of heat exchanged with the circulating refrigerant decreases, so the second electric expansion valve 19 controls the amount of refrigerant circulating through the indoor unit A to a degree of supercooling. In order to maintain a predetermined degree of supercooling even with a reduced heat exchange amount,
Control is performed to reduce the amount of refrigerant circulating within the indoor unit A by changing the opening degree to the valve closing side. As a result, the amount of refrigerant circulating through indoor unit B in room B increases, and therefore the air conditioning capacity of indoor unit B, which had previously been operated at an air conditioning capacity lower than the load level in room B, is now equal to the load level above. , or by the same amount or more, and as a result, the room temperature in room B side also increases quickly.

In this way, in the above case, as a result of selecting indoor units with capacities that are more suitable for the load level of each room, the air conditioning capacity is For example, after securing rapid heating during heating operation on the surplus side, is there a control on the refrigerant distribution amount that reduces the amount of refrigerant circulation on the surplus side and increases the amount of refrigerant circulation on the deficit side? I[l is performed. As a result, as each indoor unit,
In addition to being more suitable for the load level of each room, if the total capacity of each indoor unit is selected to be equal to the total indoor load level, the excess air conditioning capacity will be diverted to the insufficient air conditioning capacity. As a result, the operating state in which the air conditioning capacity is biased based on the capacity ratio of each indoor unit will not continue as in the past, and the speed of heating during heating operation will be improved in the room where the capacity is insufficient, for example. It is assumed that the operation will be carried out to obtain sufficient results.

In addition, in the above explanation, the simultaneous start of heating operation in room A and room B was explained as an example, but there may be cases where another indoor unit is newly operated while one indoor unit is operating, or During simultaneous operation of a room or four rooms, and even during cooling operation, the above-mentioned control will mutually compensate for excesses and deficiencies in air-conditioning capacity to improve air-conditioning comfort in each room. Further, in the above embodiment, step S2 in FIG.
Although the average load calculation means 41 and the air volume control means 42 are configured in step S5 and in step S5, other configurations having similar functions can be used. Furthermore, in the above embodiment, the indoor fan 2 can be switched to four stages.
5, but in addition to installing an indoor fan that can continuously change the air volume, for example, instead of making a judgment based on the comparison with the reference temperature difference Δ, for example, the detected air conditioning load and the average It is also possible to configure the air volume to be reduced in accordance with the difference between the load and the load.

(Effects of the Invention) As described above, in the air conditioner of the present invention, even when an indoor unit with a capacity slightly smaller than the load level is installed in a certain room, the detected air conditioning load in other rooms is reduced. When the air conditioning capacity of the above indoor units is increased, the lack of air conditioning capacity is resolved, and therefore, even when indoor units with capacities that match the load level of each room are selected, the decline in air conditioning comfort is minimized. Since it is possible to maintain stable operation, the total capacity of each indoor unit can be made smaller than in the past, and as a result, installation costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of the present invention, Fig. 2 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the invention, Fig. 3 is an operation control system diagram of the air conditioner, and Fig. 4 is a diagram of the air conditioner. It is a flowchart of the control performed by the air conditioning load monitoring control section in the conditioner. X...Outdoor unit, A-D...Indoor unit, 19...Second
Electric J expansion valve (flow control means), 25... Indoor fan, 33... Room temperature sensor (air conditioning load detection means), 41.
. . . Average load calculation means, 42 . . . Air volume changing means. Patent applicant Daikin Industries, Ltd. Figure 3/ × Figure 4

Claims (1)

[Claims] 1. Connect multiple indoor units (A to D) in parallel to one outdoor unit (X), and control the degree of superheating or overheating of the amount of refrigerant circulating through each indoor unit (A to D). An air conditioner comprising a flow rate control means (19) for controlling the degree of cooling, an air conditioning load detection means (33) for detecting the air conditioning load in each room, and an average of the detected air conditioning loads in each room. an average load calculating means (41), and an air volume changing means (41) for reducing the rotational speed of the indoor fan (25) in the indoor unit (A...) in a room where the detected air conditioning load is smaller than the average load.
42).