JPH0240457A - Multiroom type air conditioner - Google Patents

Abstract

PURPOSE:To perform delicate refrigerant flow control by parallell connecting two electrically operating expansion valves connected to a control circuit between an outdoor heat exchanger and an indoor heat exchanger. CONSTITUTION:Two electrically operating expansion valves 24, 25 are provided in parallel to an outdoor heat exchanger 23 in an outdoor machine 20. Further each indoor heat exchanger 42-45 is provided in an A machine to a D machine 38-41 connected to the outdoor machine 20 by a piece of refrigerant piping. For example, in the case where cooling operation signals are input from all the four indoor machines, the electrically operating expansion valves 24, 25 are full-opened respectively and a proper refrigerant quantity is circulated in the four indoor machines. Only an indoor machine, for example, in the case where the cooling operation signals are input from the A machine, the one-sided electrically operating expansion valve 24 alone is opened and the electrically operating expansion valve 25 remains full-closed. Thereby the proper refrigerant quantity is circulated in the A machine 38. Thus fine refrigerant flow control can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a refrigeration cycle for a multi-room air conditioner.

BACKGROUND OF THE INVENTION Conventionally, the refrigeration cycle of a multi-room air conditioner has been constructed as shown in FIG. That is, the outdoor unit 1 includes a compressor 2, a four-way valve 8, an outdoor heat exchanger 3, an electric expansion valve 4 whose opening degree is changed by a pulse signal, and a distribution capillary tube 5.
, the solenoid valve 6 and the source side three-way valve 6 are connected in sequence, and the gas side three-way valve 7, the four-way valve 8 and the accumulator 9 are connected,
An outdoor blower 1o for blowing air to the outdoor heat exchanger 3 is provided. Furthermore, each of the four indoor units 11 connected to the outdoor unit 1 through refrigerant piping is provided with an indoor heat exchanger 12 and an indoor blower 13 for blowing air.

In such a conventional refrigeration cycle, for example, when a cooling operation signal is sent from one of the indoor units 12, the compressor 2 compresses the refrigerant, and high-temperature gas flows through the four-way valve. 8, is condensed by an outdoor heat exchanger 3 and an outdoor blower 10, is throttled to the required flow rate by an electric expansion valve 4, is distributed by a distribution capillary tube (hereinafter abbreviated as distribution cabinet) 6, and is transmitted in response to an operation signal. Refrigerant is sent to the indoor room l1111 through the electromagnetic valve 6. In the indoor unit 11 that issued the operation command, the indoor blower 13 operates, and the refrigerant is evaporated in the indoor heat exchanger 12 and returned to the outdoor unit 1 through the refrigerant piping, passes through the four-way valve 8, and is transferred to the accumulator 9. It goes into.

Here, since the amount of refrigerant circulation changes greatly depending on the number of operating indoor units 12, when four indoor units 12 are in operation, that is, when the amount of refrigerant circulation is the largest, the electric expansion valve 4 is nearly fully open at 220 pulses in this case. An electric expansion valve 4 having a flow rate characteristic is used, and the electric expansion valve 4 is controlled so that the refrigerant circulation amount becomes appropriate when one unit is operated, when two units are operated, and when three units are operated.

Furthermore, when the compressor is controlled by an inverter, the opening degree of the electric expansion valve is controlled more precisely in accordance with the amount of refrigerant circulation.

Also, in the case of heating, the refrigeration cycle is reversed, but the electric expansion valve 4 is controlled in the same way as in the case of cooling.

Problems to be Solved by the Invention In such a conventional configuration, since the electric expansion valve 4 is determined by the refrigerant circulation amount when four units are operated, it is necessary to use a large-flow electric expansion valve 4 as in the past. Therefore, the flow rate per pulse is higher than that of an electric expansion valve with a small flow rate.
When the amount of refrigerant circulation is small when one unit is operated, and the opening degree of the electric expansion valve 4 corresponding to one unit operation is reduced to, for example, 26 pulses, the pulse value and the amount of refrigerant circulation shown in FIG. As is clear from the correlation diagram, between 26 pulses and 26 pulses, the refrigerant circulation rate is 30% to 31% per hour.
．． The problem was that it was only controlled between 2 and 9 hours per hour, and it was difficult to achieve proper overheating.

Further, the electric expansion valve 4 of the large flow rate type has a problem in that the flow rate varies widely, which adversely affects the capacity and other performance depending on the product.

The present invention solves the above-mentioned conventional problems, and aims to provide an air conditioner that can perform fine refrigerant flow rate control when multiple rooms are equipped with indoor units.

Means for Solving the Problems In order to solve the problems, the present invention provides a compressor, a four-way valve,
A multi-chamber refrigeration cycle is provided in which an outdoor heat exchanger, a plurality of indoor heat exchangers, etc. are sequentially connected, and an electric expansion valve connected to a control circuit is provided between the outdoor heat exchanger and each of the indoor heat exchangers. Two pieces are connected in parallel.

Function: With this configuration, the opening degree of the two electric expansion valves is controlled depending on the number of units operated indoors, and this control is used to adjust the opening degree of each electric expansion valve to an appropriate amount of refrigerant circulation in response to a pulse signal. This will result in a degree of control.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a refrigeration cycle diagram, in which the outdoor unit 20 includes a compressor 21, a four-way valve 22, and an outdoor heat exchanger 2.
3, two electric expansion valves 24, 25 arranged in parallel, distribution capillary tubes 26, 27° 28, 29 connected in parallel corresponding to the number of indoor units, and a solenoid valve 30 for unit A. The solenoid valve 31 for the B unit, the solenoid valve 32 for the C unit, the solenoid valve 33 for the D unit, and the source side three-way valve 34 are connected in sequence, and the gas side three-way valve 36, the four-way valve 22, and the accumulator 36 are connected, and the outdoor An outdoor blower 37 for blowing air to the heat exchanger 23 is provided. In addition, each of the four indoor units connected to the outdoor unit 2° by refrigerant piping, that is, unit A 38, unit B 39, unit C 40, and unit D 41, has an indoor heat exchanger, that is, a unit indoor heat exchanger 42, A B-unit indoor heat exchanger 43, a C-unit indoor heat exchanger 44, a D-unit indoor heat exchanger 46, and an indoor blower 46 for blowing air are provided.

Figure 2 is a control circuit diagram, each indoor unit control circuit block A
Operation stop signals from the unit control circuit 47, unit B control circuit 48, unit C control circuit 49, and unit D control circuit 60 are input to the microcomputer (hereinafter abbreviated as "Yacon") 62 of the outdoor unit control circuit 61, and the microcomputer 62 calculates the operation stop signal. Relay 53 for outdoor blower, solenoid valve relay 64 for unit A, solenoid valve relay 66 for unit B, solenoid valve relay 56 for unit C, solenoid valve relay 67 for unit D, expansion valve drive circuit 68, 59, compressor The 0N10FF signal is output to the four-way valve relay 60 and the four-way valve relay 61.

In the above configuration, for example, when cooling operation signals are received from all four indoor units, the microcomputer 62 calculates the signals, and calculates the outdoor blower relay 63, the solenoid valve relay 64 for unit A, the solenoid valve relay 55 for unit B, and the solenoid valve relay 55 for unit C. An ON signal is sent to the solenoid valve relay 56, the D unit solenoid valve relay 67, and the compressor relay 60, and the expansion valve drive circuit 58, 59 is fully open (220
PS) (Fig. 3) command is output, and the electric expansion valve 24. and 26 are fully opened to circulate the appropriate amount of refrigerant to the four indoor units. In addition, if only one indoor unit receives a cooling operation signal from the A unit control circuit 47, the microcomputer 5
2, and outputs an ON signal to the outdoor blower relay 63, unit A solenoid valve relay 64, and compressor relay 60,
A command signal is sent to the expansion valve drive circuit 58 to open the appropriate opening degree when one unit is operated, for example, a 6o pulse as shown in FIG. 25 is left fully open. With this, pA unit 3
8, an appropriate amount of refrigerant is circulated.

This will be explained with reference to FIG. 3, which shows the flow rate characteristics of a small flow type electric expansion valve according to an embodiment. For example, when operating 4 units, if a refrigerant circulation rate of 150 mm/h is required, if a conventional large flow leaf type electric expansion valve 1WA is used, the refrigerant circulation rate will be 22 mm as shown in Figure 4.
q/h is 160 at 0 pulse, and when using two small flow basin type electric expansion valves in parallel in this embodiment, q/h is 2 as shown in Fig. 3.
By making them both 220 pulses, each 7 s
Ky/b for a total of 150 Ky/h. Also, if the required amount of refrigerant when operating one unit is, for example, 30K9/h, if one conventional large-flow leaf type electric expansion valve is used, it will require 25 pulses.If the electric expansion valve makes a drive mistake, etc. 1
1.2 per pulse! 7/h (2 as shown in Figure 4)
6ha/l/7. 28. 31. due to pulse difference.
There is a difference in the refrigerant circulation rate of 9/h=1.2/h) from 2/h to 30/h, but in the case of using two small-flow electric expansion valves in this example, the difference is 30 K9/h. Around h, there are 5 o pulses, and even if the electric expansion valve makes a drive mistake, o every pulse, a is 9/h (50 pulses shown in Fig. 3, and 5 o pulses as shown in Fig. 3).
30.6 Ks+/h -30Ky due to 1 pulse difference
/ h = o, eKz/h), which is the only difference in the amount of refrigerant circulation. Furthermore, as is clear from FIG. 3, as the opening degree of the electric expansion valve increases, the increase in the amount of refrigerant circulation slows down, so the flow rate variation of the electric expansion valve becomes larger as the opening degree becomes smaller. In other words, the small flow type electric expansion valve, which has a larger opening degree even with the same amount of refrigerant circulation, has a higher opening degree than the conventional electric expansion valve shown in FIG. 4, and the present example shown in FIG. When the refrigerant circulation amount is used at a position above the point υ, the flow rate variation becomes small per pulse. Therefore, when obtaining the same amount of refrigerant circulation around eoKs+/h, the difference in per pulse is smaller when used at the position of line G shown in Figure 3 than when used at the straight line position shown in Figure 4. , will be accurate.

Effects of the Invention As is clear from the description of the embodiments described above, according to the present invention, two small-flow electric expansion valves are connected in parallel between the outdoor heat exchanger and the capillary tube corresponding to each indoor unit. By connecting each electric expansion valve, the number of operating indoor units,
Since the degree of opening is changed according to the load in the room, the flow rate can be controlled more precisely than in the past, and the pEER can be improved.

It also has the effect of eliminating deterioration in product performance due to variations in the flow rate of the electric expansion valve.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram of a multi-chamber air conditioner according to an embodiment of the present invention, FIG. 2 is a control circuit diagram of the multi-chamber air conditioner,
Figure 3 is a flow rate characteristic diagram showing the correlation between the small-flow electric expansion valve and pulse used in the same multi-chamber air conditioner, and Figure 4 is the large-flow expansion valve used in the conventional multi-chamber air conditioner. FIG. 5 is a flow rate characteristic diagram correlated with the pulse of the air conditioner, and FIG. 5 is a refrigeration cycle diagram of the conventional air conditioner. 21...Compressor, 22...Four-way valve, 2
3...Outdoor heat exchanger, 42.43.44.45
...Indoor heat exchanger, 24.25...Electric expansion valve. Name of agent: Patent attorney Shigetaka Awano and one other person
11"lL for Δ 2ftrn%jB
t+tR si'Mix (PS>Fig.

Claims (1)

[Claims] Equipped with a multi-chamber refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, a plurality of indoor heat exchangers, etc. are sequentially connected, and a control circuit is connected between the outdoor heat exchanger and each of the indoor heat exchangers. A multi-chamber air conditioner consisting of two electric expansion valves connected in parallel.