JP2515862B2 - Multi-room air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat pump type multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit, and in particular, when any indoor unit is idle. Of the excess refrigerant control.

[Prior Art] As described in Japanese Patent Publication No. 61-128069, a conventional device is connected to each indoor unit as a surplus refrigerant control means when an arbitrary indoor unit is idle in a multi-room air conditioner. A motor-operated valve is installed on the liquid side branch pipe of the outdoor unit, and a predetermined opening degree is set in the motor-operated valve corresponding to the operating indoor unit according to the number of operating indoor units. While the motor-operated valve is corrected so that the average refrigerant temperature of each liquid side branch pipe is adjusted, the motor-operated valve corresponding to the pause unit is set to a small opening to prevent refrigerant from accumulating in the pause unit. Furthermore, when the refrigerant temperature of the liquid side branch pipes corresponding to the pause unit is lower than the temperature of each liquid side branch pipe, the electric valve corresponding to the pause unit is further opened and corrected so that the refrigerant accumulates in the pause unit. Was prevented.

[Problems to be Solved by the Invention]

In the above-mentioned conventional technology, the main purpose is to remove the refrigerant accumulated in the pause unit, and when it is determined that the refrigerant has accumulated, the opening degree of the electric valve corresponding to the pause unit is further increased to extract the refrigerant. It was However, in this method, since the control is stepwise and operates independently of the motor-operated valve on the operating unit side, the influence during extraction may interfere with the motor-operated valve control on the operating unit side. However, there is a problem in that there is a possibility that the control may be repeated by hunting even when the load is stable.

An object of the present invention is to solve the above-mentioned problems and perform refrigerant control so as to stabilize the operation cycle, and obtain a comfortable air conditioning state.

[Means for solving the problem]

The purpose is to control the capacity of the compressor, the outdoor heat exchanger,
A single outdoor unit including a four-way valve and a plurality of indoor units having an indoor heat exchanger are provided, and a liquid-side main pipe is branched into a plurality of pipes in the middle of a connecting pipe of the indoor-outdoor unit, and each of the liquid-side branch pipes. In a multi-chamber air conditioner in which a heat-pump refrigeration cycle is formed by installing an electric expansion valve in the, a discharge gas temperature detector that detects the discharge gas temperature of the refrigerant during heating operation, and a condensing unit that detects the condensation temperature of the refrigerant Calculates the refrigerant discharge superheat degree from the temperature detector and the temperature data detected by both temperature detectors, and responds to the operating indoor unit so that the refrigerant discharge side superheat degree becomes a predetermined value based on this calculation result. While controlling the valve opening degree of the expansion valve, the opening degree adjustment amount for the operating unit side electronic expansion valve is also output to the expansion valve corresponding to the resting indoor unit by reducing it by a predetermined ratio. , A small amount of refrigerant is circulated in the pause unit as well, so that the opening valve for the expansion valve corresponding to the pause unit is adjusted to an amount corresponding to the opening adjustment amount on the operating unit side. This is achieved by providing a refrigerant control device that is determined according to a program that is input in advance and a control signal output device that outputs an opening amount to the expansion valve according to the determined control content and that drives the expansion valve.

[Action]

The control device takes in the discharge gas temperature and the condensation temperature of the refrigerant from the temperature detector, and determines the refrigerant discharge side superheat degree from the difference between these two temperatures. Then, the opening degree adjustment amount of the electric expansion valve whose discharge side superheat degree becomes the target value is calculated, and the valve opening adjustment amount of the electric expansion valve corresponding to each unit of the operation unit and the pause unit is calculated through the control signal output device. Output. At this time, the valve opening adjustment amount of the electric expansion valve corresponding to the pause unit is an amount obtained by multiplying the valve opening adjustment amount of the expansion valve corresponding to the operation unit by a predetermined ratio. Circulate a small amount of refrigerant. As a result, refrigerant does not accumulate in the pause unit and runs short of refrigerant during the operation cycle. In addition, refrigerant corresponding to the load circulates in the operating unit, and the opening adjustment control of the electronic expansion valve corresponding to the pause unit is linked to the operating unit side, so the electronic expansion valves on the operating unit side and the pause unit side The effect of eliminating mutual interference is obtained.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention. The air conditioner in this embodiment has three outdoor units.
The outdoor unit is provided with a compressor 1, a four-way valve 2, an accumulator 3, an outdoor heat exchanger 4 and a receiver 6 provided in the refrigerant liquid side main pipe 5. ing. In addition, the three liquid side branch pipes 7a, 7b, 7c that branch off the refrigerant liquid side main pipe 5 are respectively provided with reversible electric expansion valves.
8a, 8b, 8c are provided. Then, indoor heat exchangers 9a, 9b, 9c are provided on the indoor unit side, respectively, and each equipment in the outdoor unit and each equipment in the indoor unit are connected by piping as shown in FIG. Are configured. Further, in the outdoor unit, a detector 10 for detecting the discharge gas temperature of the refrigerant in the refrigerant discharge pipe 1a,
A detector 11 for detecting the refrigerant condensation temperature in the condensation pipe 1b branched from the refrigerant discharge pipe, the detector is connected, and the refrigerant control device 12 and the refrigerant control device 12 for processing the detected contents by a program input in advance. And a control signal output device 13 for outputting the expansion valve opening adjustment amount to the electric expansion valves 8a, 8b, 8c in response to the command.

The operation of the embodiment of the present invention configured as described above will be described with reference to FIG.

FIG. 2 shows the control flow of this embodiment, and FIG. 3 shows the movement of the opening degree of the electric expansion valve corresponding to the operation unit and the stop unit.

First, consider a case where two indoor heat exchangers 9a and 9b are operated and one indoor heat exchanger 9c is stopped.

When two indoor units having the indoor heat exchangers 9a, 9b are operated, the refrigerant gas from the compressor 1 passes through the four-way valve 2 and the gas side main pipe 15 and the gas side branch pipes 14a, 14b, and the indoor heat exchangers 9a, 9b It is sent to 9b and condensed. And the electric expansion valves 8a, 8b,
The liquid-side branch pipes 7a and 7b, the liquid-side main pipe 5, and the receiver 6 are sequentially sent to the outdoor heat exchanger 4, evaporated to become gas, and return to the compressor 1 via the four-way valve 2 and the accumulator 3. here,
Expansion valve corresponding to a pause unit with an indoor heat exchanger 9c
The opening of 8c is maintained at a predetermined minimum opening allowing a small amount of refrigerant to flow in the initial state.

Next, a control flow for the expansion valves 8a, 8b, 8c will be described.

In the present embodiment, the discharge gas temperature Td and the condensing temperature Tc are read from the detectors 10 and 11 into the control device 12 every predetermined time (steps 16 and 17 in FIG. 2). From the difference between these two temperature data, the superheat degree SH of the discharge side refrigerant at the present time is calculated (step 19). Then, the expansion valve opening adjustment amount ΔP is calculated from the deviation between the superheat degree SH of the discharge side refrigerant at the present time and the target superheat degree SH 'of the discharge side refrigerant by the following PID arithmetic expression (step 20).

ΔP = Ki x (SH-SH ') + Kp x (SH-SH _n-1 ) + Kd x {(SH-SH _n-1 )-(SH _n-1 -SH _n-2 )} ΔP: Expansion valve opening Adjustment amount Ki, Kp, Kd: Constant SH: Current superheat degree of discharge side refrigerant SH ': Target superheat degree of discharge side refrigerant SH _n-1 : Superheat degree of discharge side refrigerant at one sampling before the present SH _n-2 : Superheat degree of refrigerant on the discharge side at the time of sampling two times before now After calculating the expansion valve opening adjustment amount ΔP by the above formula,
It is distributed to the indoor units of each operation according to the following formula (step 21).

ΔPi = Qi / ΣQi × ΔP ΔPi: Opening adjustment distribution amount for each operating indoor unit Qi: Code that indicates the capacity of each operating indoor unit ΔP: Total expansion valve opening adjustment amount for all operating indoor units Further, the expansion valve opening degree is distributed to the pause unit by the following formula (step 22).

ΔPj = Qj / (ΣQi + ΣQj) × ΔP ΔPj: Amount of opening adjustment distribution to each idle unit Qj: Code indicating the ability of each idle unit Qi: Code indicating the ability of each operating unit ΔP: Indoor unit during all operations Total expansion valve opening adjustment amount with respect to the above Expression is used to distribute the opening adjustment amount to the indoor unit and the rest indoor unit during operation. As a result, the pause unit distributes the total expansion valve opening adjustment amount ΔP by the ratio of the code of the ability of each pause unit to the total code of the ability of the installed indoor units, and the capacity is provided to the operating indoor unit. Since the distribution is performed by the ratio of the code of the capacity of each operation unit to the total code of, the rest unit is distributed with a smaller opening degree than the indoor unit in operation.
Further, as the initial valve opening degree of the expansion valve corresponding to the in-chamber indoor unit is maintained at the minimum opening degree capable of allowing a small amount of refrigerant to flow, the expansion valve opening degree 24 corresponding to the operating unit as shown in FIG. Compared with, the response follows the indoor unit side during operation, but is suppressed to a low opening as an absolute value of the expansion valve opening. The expansion valve opening correction operation is performed every predetermined sampling time T seconds as shown in step 23 of FIG.

By the control as described above, it becomes possible to control the superheat degree of the discharge side refrigerant in the entire operation cycle.

Second Embodiment Next, a second embodiment of the present invention will be described in which a pressure sensor is used as a component instead of the condensation temperature detector 11 of the first embodiment.

Here, as the flow of control, in step 18 of FIG. 2, the discharge pressure is taken in as data instead of the temperature data, and when the refrigerant discharge side superheat degree is calculated in step 19, the condensation temperature is calculated from the discharge pressure, Calculate discharge side superheat. Further, the calculation for obtaining the condensation temperature from the discharge pressure is performed by a program stored in advance in the refrigerant control device 12. Other configurations and control flows are the same as in the first embodiment. Even with this structure, the same effect as that of the first embodiment can be obtained.

Note that the present invention is not limited to the above embodiment, for example, it is possible to directly detect the condensation temperature from the outdoor heat exchanger, and the expansion valve mechanism is the outdoor unit as in the present embodiment. The present invention can be applied not only to those provided in the above, but also to the case where it is provided in the middle of the piping between the indoor unit and the indoor unit and the outdoor unit, and various modifications can be made without changing the gist.

〔The invention's effect〕

According to the present invention, in a multi-room air conditioner, even when any indoor unit among a plurality of indoor units is deactivated, the refrigerant does not accumulate in the deactivated indoor unit and the amount of refrigerant is insufficient during the operation cycle. Can be prevented. In addition, the amount of refrigerant circulating to the operating unit is secured, and there is no interference between the electric expansion valves corresponding to the operating unit and the pause unit, and a stable refrigeration cycle can be obtained. This makes it possible to achieve a comfortable air conditioning state.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle system diagram showing a first embodiment of a multi-room air conditioner of the present invention, FIG. 2 is a control flow chart of the first embodiment, and FIG. FIG. 1 ... compressor, 4 ... outdoor heat exchanger, 8a, 8b, 8c ... motorized expansion valve, 9a, 9b, 9c ... indoor heat exchanger, 12 ... refrigerant control device, 13 ... control signal Output device.

Front page continued (72) Inventor Go Hiyoshi, 390 Muramatsu, Shimizu, Shizuoka Prefecture, Shimizu Plant, Shimizu Plant (72) Inventor, Katsumasa Saeki, 390, Muramatsu, Shimizu City, Shizuoka, Ltd. ) Inventor Osamu Seki 390 Muramatsu, Shimizu City, Shizuoka Prefecture Inside the Shimizu Plant, Hiritsu Manufacturing Co., Ltd.

Claims (1)

(57) [Claims] 1. An outdoor unit including an outdoor unit and an indoor unit, which comprises one outdoor unit including a compressor whose capacity can be controlled, an outdoor heat exchanger, and a four-way valve, and a plurality of indoor units having an indoor heat exchanger. In a multi-chamber air conditioner in which a heat-pump refrigeration cycle is formed by branching the liquid-side main pipe into a plurality of liquid-side main pipes in the middle of the connecting pipes and providing each of the liquid-side branch pipes with an electric expansion valve, the refrigerant discharge gas temperature is detected. A discharge gas temperature detector, a condensation temperature detector that detects the condensation temperature of the refrigerant during heating operation, and the discharge side superheat degree of the refrigerant is calculated from the temperature data detected by both temperature detectors, and based on this calculation result. While controlling the valve opening of the expansion valve corresponding to the operating indoor unit so that the refrigerant discharge side superheat becomes a predetermined value, also for the expansion valve corresponding to the dormant indoor unit. Outputs the opening adjustment amount for the rotary unit side electronic expansion valve after reducing it by a predetermined ratio, circulates a small amount of refrigerant also to the pause unit, and adjusts the opening degree for the expansion valve corresponding to the pause unit on the operating unit side. A refrigerant control device that determines the content of control to the expansion valve according to a program that is input in advance so as to make the amount according to the amount, and the expansion valve that outputs the opening amount to the expansion valve according to the determined control content. A multi-room air conditioner characterized by being provided with a control signal output device for driving.