KR20050011530A - a heat pump system and an operating control method for the same - Google Patents

Abstract

PURPOSE: A multi-air conditioner and an operation control method thereof are provided to restrict an inverter compressor from overheating and to increase the heat-exchanging efficiency by preventing the flow of refrigerant from decreasing by resetting a target discharge overheating degree even if the inverter compressor is operated slower than a constant-speed compressor. CONSTITUTION: A multi-air conditioner is composed of an inverter compressor(54) operated at variable velocity and a constant-speed compressor(56) operated at constant velocity; a condenser for condensing refrigerant passing through the inverter compressor or the constant-speed compressor; an electronic expansion valve for controlling the flow of refrigerant by regulating an opening value to decompress the refrigerant passing through the condenser; and a microcomputer for resetting a target discharge overheating degree to prevent the inverter compressor from overheating if the inverter compressor is operated slower than the constant-speed compressor and regulating the opening value of the electronic expansion valve according the reset target discharge overheating degree.

Description

Multi type air conditioner and operation control method {a heat pump system and an operating control method for the same}

The present invention relates to a multi-type air conditioner in which an inverter compressor and a constant speed compressor are applied to control the operation according to a cooling or heating load, and a method of controlling the same. The present invention relates to a multi-type air conditioner and an operation control method thereof, by which the inverter compressor is prevented from being overheated, thereby increasing the reliability and heating efficiency of the compressor.

In general, an air conditioner includes refrigerant circulating along a compressor, a condenser, an expansion device, and an evaporator, and an outdoor heat exchanger and an indoor heat exchanger respectively installed on an outdoor side and an indoor side during cooling serve as a condenser and an evaporator, respectively. When the outdoor heat exchanger and the indoor heat exchanger serve as the evaporator and the condenser, respectively, recently, a multi-type air conditioner has been widely used to cool / heat a large number of compartments while increasing the cooling / heating capacity.

1 is a block diagram showing a conventional multi-type air conditioner.

A conventional multi-type air conditioner is installed to connect a plurality of indoor units (1, 2, 3, 4) and one outdoor unit (5) as shown in FIG. 1 to perform a cooling or heating operation.

Here, the plurality of indoor units (1, 2, 3, 4) are the indoor heat exchangers (21, 22, 23, 24), the indoor fans (27, 28, 29, 30) and the motors (31, 32, 33), respectively. And 34, and an electromagnetic expansion valve 14, 15, 16, and 17, wherein the outdoor unit 5 includes a compressor 11, an outdoor heat exchanger 13, an outdoor fan (not shown), A motor (not shown) is configured to include the compressor 11, the outdoor heat exchanger 13, the electromagnetic expansion valves 14, 15, 16, and 17, and the indoor heat exchangers 21, 22, 23, and 24. In addition to being connected to each other by the refrigerant pipe 9, such components are controlled by a microcomputer (not shown).

At this time, the electromagnetic expansion valve (14, 15, 16, 17) may be configured to be included in the outdoor unit (5).

Of course, the outdoor heat exchanger 13 and the indoor heat exchanger 14, 15, 16, 17 serve as condensers and evaporators, respectively, while the multi-type air conditioner is connected to the outdoor heat exchanger 13 during heating. Indoor heat exchangers 14, 15, 16, and 17 serve as evaporators and condensers, respectively.

In particular, the compressor (11) is composed of a plurality of compressors (11a, 11b) for compressing the refrigerant into a gas refrigerant of high temperature and high pressure, the inverter compressor (11a) is shifted to change the capacity according to the cooling or heating load, It is composed of a constant speed compressor (11b) in constant speed operation so that the capacity is constant, it is selectively operated by the microcomputer.

Reference numeral 12 is a four-way valve 12 that sends the high-temperature, high-pressure gas refrigerant from the compressor 11 to the outdoor heat exchanger 13 when cooling, and to the indoor heat exchangers 21, 22, 23, and 24 when heating. And a flow of refrigerant circulated by the control unit to circulate the compressor 11, the outdoor heat exchanger 13, the expansion valves 14, 15, 16, 17, and the indoor heat exchanger 21, 22, 23, 24. By switching to each of the indoor units (1, 2, 3, 4) can be used as a heater or cooler.

In addition, reference numeral 19 indicates that the liquid refrigerant, which has not been evaporated in the indoor heat exchanger 21, 22, 23, 24, may cause a failure of the compressor 11 when the refrigerant enters the compressor 11. It is an accumulator in which liquid refrigerant is stored to prevent.

Usually, when the cooling or heating load is small, the inverter compressor 11a is operated at a low speed to relieve the load. However, as the cooling or heating load is increased, the inverter compressor 11a is operated at a high speed gradually to relieve the load. If is not eliminated, the inverter compressor (11a) and the constant speed compressor (11b) is operated at the same time to eliminate the load.

In addition, the electronic expansion valve (14, 15, 16, 17) is the opening value is adjusted to adjust the flow rate of the refrigerant in accordance with the cooling or heating load, this opening value is the current discharge superheat (t) to the microcomputer The target discharge superheat degree t ₀ is adjusted to be input.

Here, the first temperature sensor 42 installed on the discharge side of the inverter compressor (11a) and the constant speed type compressor (11b) and the second temperature sensor installed on the side of the outdoor heat exchanger (13) serving as a condenser during the cooling operation. The current discharge superheat degree t is calculated by the refrigerant temperature T ₁ on the compressor discharge side and the refrigerant temperature T ₂ on the condenser side respectively sensed by (44), and this current discharge superheat degree t The opening value of the electromagnetic expansion valve 6 is generally adjusted within the range of 0 to 500 pulses or 0 to 2000 pulses so that is equal to the target discharge superheat degree t ₀ .

Of course, the second temperature sensor 44 is preferably configured to be installed on the indoor heat exchanger (21, 22, 23, 24) side that serves as a condenser during the heating operation.

That is, in the multi-type air conditioner according to the related art as described above, the operation of the inverter compressor 11a and the constant speed compressor 11b is controlled by the microcomputer according to the cooling or heating load, and the electromagnetic expansion valves 14 and 15 The opening degree of (16,17) is controlled.

In particular, in the multi-type air conditioner according to the related art, when the inverter compressor 11a and the constant speed compressor 11b are operated at the same time according to a cooling or heating load, the inverter compressor 11a is lower than the constant speed compressor 11b. In operation, due to the difference in suction pressure between the inverter compressor 11a and the constant speed compressor 11b, the refrigerant flows more toward the constant speed compressor 11b which is operated at a relatively high speed, while the inverter compressor is operated at a relatively low speed. Less flows into the (11a) side.

Therefore, as the flow rate of the refrigerant flowing into the inverter compressor 11a decreases, even though the inverter compressor 11a is operated at the same speed, the discharge temperature of the refrigerant passing through the inverter compressor 11a increases, thereby increasing the flow rate of the refrigerant. As the internal temperature of 11a is increased and the inverter compressor 11a is overheated, the reliability of the inverter compressor 11a is lowered and the flow rate decreases even if the discharge temperature of the refrigerant passing through the inverter compressor 11a is high. There is a problem that the cooling or heating efficiency is lowered because the heat transfer efficiency is lowered.

The present invention has been made to solve the above problems of the prior art, even if the inverter compressor is operated at a lower speed than the constant speed type compressor to reset the target discharge superheat so as not to reduce the flow rate of the refrigerant flowing into the inverter compressor side of the inverter compressor It is an object of the present invention to provide a multi-type air conditioner and its operation control method which can prevent overheating and improve heat exchange efficiency.

1 is a configuration diagram showing a conventional multi-type air conditioner,

2 is a perspective view showing a multi-type air conditioner according to the present invention;

3 is a block diagram showing an outdoor unit of the multi-type air conditioner according to the present invention;

4 is a configuration diagram showing a plurality of indoor units of the multi-type air conditioner according to the present invention;

5 is a block diagram showing an operation control apparatus of a multi-type air conditioner according to the present invention.

6 is a flowchart illustrating an operation control method of a multi-type air conditioner according to the present invention.

<Explanation of symbols on main parts of the drawings>

54: inverter compressor 56: constant speed compressor

79: Microcomputer 106,116,126,: Electronic expansion valve

t: Current discharge superheat t ₁ : First target discharge superheat

t ₂ : second target discharge superheat

Multi-type air conditioner according to the present invention for solving the above problems is a variable speed drive inverter compressor and a constant speed constant speed compressor, a condenser for condensing the refrigerant passing through the inverter compressor or a constant speed compressor, passing through the condenser An electronic expansion valve for adjusting a flow rate by adjusting an opening value to reduce a refrigerant, and resetting a target discharge superheat degree to prevent the inverter compressor from overheating when the inverter compressor is operated at a lower speed than the constant speed compressor. And a microcomputer for adjusting the opening value of the electromagnetic expansion valve according to the reset target discharge superheat degree.

In addition, the operation control method of the multi-type air conditioner according to the present invention includes a first step of simultaneously operating the inverter compressor and the constant speed compressor according to the cooling or heating load, and the inverter compressor and the constant speed compressor operated in the first step. A second step of detecting the operating speed, and a third step of resetting the target discharge superheat degree when the inverter compressor is operated at a lower speed than the constant speed compressor as a result of the detection of the second step.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view showing a multi-type air conditioner according to the present invention.

As shown in FIG. 2, the multi-type air conditioner according to the present invention is configured such that a plurality of indoor units 110, 110, and 120 are connected to one outdoor unit 50, and the outdoor unit 50 serves as a condenser to condense a refrigerant during cooling operation. On the other hand, the outdoor heat exchanger 52, which serves to evaporate the refrigerant, and the outdoor fan 57, which blows the outdoor air to the outdoor heat exchanger to exchange heat with the refrigerant, and a refrigerant compression capacity for compressing the refrigerant. It is configured to include an inverter compressor (54) that can vary the variable speed compressor (56) that can maintain a constant refrigerant compression capacity.

Reference numeral 79 is a microcomputer that controls the inverter compressor 54, the constant speed compressor 54, the outdoor fan 58, and the like in response to the load of the plurality of indoor units 100, 110, 120.

3 is a block diagram showing the outdoor unit of the multi-type air conditioner according to the present invention.

Specifically, the outdoor unit 50 is oil discharged with the refrigerant in addition to the outdoor heat exchanger 52 and the outdoor fan 57, the inverter compressor 54 and the constant speed compressor 56 as shown in FIG. Oil separators 58 and 61 connected to the inverter compressor 54, the constant speed compressor 56, and the refrigerant discharge pipes 54a and 56a to separate the refrigerant from the refrigerant, and the oil separators 58 and 61. Oil return piping connected to the refrigerant suction pipes 54b and 56b of the inverter compressor 54 and the constant speed compressor 56 to return the oil separated from the inverter to the inverter compressor 54 and the constant speed compressor 56. 59 and 62 and check valves 60 and 63 mounted to the refrigerant discharge pipes 54a and 56a of the inverter compressor 54 and the constant speed compressor 56, respectively, to prevent backflow of refrigerant or oil. It is configured to include.

In addition, since the flow rate of the refrigerant is controlled by the microcomputer 79 so that the current discharge superheat degree matches the target discharge superheat degree stored in advance, a temperature difference value of the compressed refrigerant and the condensed refrigerant is In order to measure the current degree of superheat, the first temperature sensor 142 installed on the discharge side of the inverter compressor 54 and the constant speed compressor 56 and the outdoor heat exchanger 52 side serving as a condenser during cooling operation. The second temperature sensor 144 installed in the further comprises.

Reference numeral 70 is mounted in the outdoor unit 50 and is connected to the refrigerant suction pipes 54b and 56b of the inverter compressor 54 and the constant speed compressor 56 so that the inverter compressor 54 and the constant speed compressor 56 are not shown. It is a common accumulator that accumulates liquid refrigerant so that only gaseous refrigerant can flow into each.

Reference numeral 72 is any one of the indoor heat exchanger and the outdoor heat exchanger 52 of the refrigerant passing through the oil separators 58 and 60 mounted in the outdoor unit 50 to use the plurality of indoor units as a cooler or a heater. Four-way valve to switch the flow path to flow into.

Reference numeral 74 is a receiver mounted in the outdoor unit 50 to store excess refrigerant and to circulate only the liquid refrigerant to the indoor unit during the cooling operation.

Reference numeral 76 denotes an expansion device for expanding the refrigerant passing through the outdoor heat exchanger 52 and sending it to the indoor heat exchanger during heating, which is mounted on the refrigerant pipe connecting the outdoor heat exchanger 52 and the receiver 74. A bypass valve 76a through which the refrigerant blocked by the check valve 76a is bypassed, and an electromagnetic expansion valve 76c through which the refrigerant bypassed by the bypass pipe 76b is expanded; LEV).

Reference numeral 78 denotes a strainer mounted on the refrigerant pipe to filter foreign matter mixed in the refrigerant or oil.

Figure 4 is a block diagram showing a plurality of indoor units of the multi-type air conditioner according to the present invention.

Specifically, the indoor units (100, 110, 120) are sucked into the indoor fans (102, 112, 122) and the indoor units (100, 110, 120) to suck the indoor air in the space in which the indoor units (100, 110, 120) are installed, and then discharge them back into the room. It is configured to include an indoor heat exchanger (104, 114, 124) (LEV) for inflating the refrigerant, while the heat exchange with the refrigerant to perform the role of the evaporator during the cooling operation, while acting as a condenser during the cooling operation. .

Then, the refrigerant passing through each of the indoor units (100, 110, 120) is combined in the joint pipe 132 and then introduced into the outdoor unit, the refrigerant passing through the outdoor unit 50 is distributed to the branch pipe (134, 136, 138) to each indoor unit (100, 110, 120) Flows into).

5 is a block diagram showing an operation control apparatus of a multi-type air conditioner according to the present invention.

As shown in FIG. 5, the multi-type air conditioner configured as described above operates the inverter compressor 54 and the constant speed compressor 56 by the microcomputer 79, and the opening values of the electromagnetic expansion valves 106, 116, and 126. Etc., the refrigerant compression capacity is varied according to the cooling / heating load and the flow rate of the circulating refrigerant is adjusted.

At this time, the opening value of the electromagnetic expansion valve (106, 116, 126) is adjusted to control the flow rate of the refrigerant, the opening degree is the current discharge superheat (t) is input to the microcomputer (79) as shown in FIG. Is adjusted so that the previously input target discharge superheat degree.

At this time, the current discharge superheat degree (t) is the difference between the refrigerant temperature (T ₁ ) of the discharge side side of the inverter compressor 54 and the constant speed compressor 56 and the refrigerant temperature (T ₂ ) of the heat exchanger that serves as a condenser. The opening degree of the electromagnetic expansion valves 106, 116 and 126 is adjusted such that the current discharge superheat degree t is the target discharge superheat degree.

Specifically, when the current discharge superheat degree t is higher than the target discharge superheat degree, the opening value of the electromagnetic expansion valves 106, 116, 126 is adjusted to increase the flow rate of the refrigerant, while the current discharge superheat degree t is increased. Is lower than the target discharge superheat degree, the opening values of the electromagnetic expansion valves 106, 116 and 126 are adjusted to reduce the flow rate of the refrigerant.

In particular, the microcomputer 79 resets the target discharge superheat degree to prevent the inverter compressor 54 from overheating when the inverter compressor 54 is operated at a lower speed than the constant speed compressor 56. The opening values of the electromagnetic expansion valves 106, 116 and 126 are adjusted according to the reset target discharge superheat degree.

At this time, the reset target discharge superheat degree is preferably set to be lower than the previously set target discharge superheat degree.

6 is a flowchart illustrating an operation control method of a multi-type air conditioner according to the present invention.

Looking at the operation control method of the multi-type air conditioner according to the present invention configured as described above with reference to FIG.

In the first step, the inverter compressor 54 and the constant speed compressor 56 are simultaneously operated in accordance with the cooling / heating load by detecting a cooling or heating load.

Here, the inverter compressor 54 is shifted to change the capacity according to the cooling / heating load, or the inverter compressor 54 and the constant speed compressor 56 are simultaneously operated as the cooling / heating load increases. .

In the second step, as the inverter compressor 2a and the constant speed compressor 2b are operated in the first step, the target discharge superheat degree is set to the first target discharge superheat degree t ₁ , and the first The opening value of the electromagnetic expansion valve 6 is adjusted according to the target discharge superheat degree t ₁ (see S2, S3).

At this time, the electromagnetic expansion valve 6 such that the current discharge superheat degree t detected by the first temperature sensor 14 and the second temperature sensor 16 becomes the first target discharge superheat degree t ₁ . The opening value of is adjusted to the first opening value.

In the third step, the opening value of the electromagnetic expansion valve 6 is adjusted in the second step, and then the operating speed V _i of the inverter compressor and the operating speed V _c of the constant speed compressor are determined. (See S4, S5)

In the fourth step, when the driving speed V _i of the inverter compressor is rotated at a lower speed than the driving speed V _c of the constant speed type compressor, the target discharge superheat degree is determined by the second target discharge superheat degree ( t ₂ ) (see S6)

Here, when the inverter compressor 2a is rotated at a lower speed than the constant speed compressor 2b, the refrigerant is operated at a relatively high speed due to the pressure difference between the inverter compressor 2a and the constant speed compressor 2b. As the temperature of the refrigerant passing through the inverter compressor 2a increases as more flows into the type compressor 2b and less flows into the inverter compressor 2a that operates at a relatively low speed, the current discharge superheat ( t) is increased to exceed the first target discharge superheat degree t ₁ .

Accordingly, in order to quickly lower the current discharge superheat degree t, the target discharge superheat degree is reset to a second target discharge superheat degree t _{2 which} is lower than the first target discharge superheat degree t ₁ . The second target discharge superheat degree t ₂ is set to be 5 ° C. lower than the first target discharge superheat degree t ₁ .

In the fifth step, the opening value of the electromagnetic expansion valve 2 is adjusted according to the second target discharge superheat degree t ₂ set in the fourth step.

At this time, the opening value of the electromagnetic expansion valve 2 is adjusted to a second opening value larger than the first opening value to increase the flow rate of the refrigerant passing through the electromagnetic expansion valve (6).

Therefore, as the flow rate of the refrigerant circulating in the multi-type air conditioner increases, the flow rate of the refrigerant flowing into the constant speed compressor 2b side increases while the flow rate of the refrigerant flowing into the inverter compressor 2a side remains constant. Not only can the inverter compressor 2a be prevented from being overheated, but the cooling or heating efficiency can be increased as the flow rate of the circulating refrigerant is increased.

In the multi-type air conditioner and its operation method according to the present invention configured as described above, the multi-type air conditioner and its operation method have a target discharge superheat t ₂ when the inverter compressor is operated at a lower speed than the constant speed type compressor. Is operated at the same speed as the constant speed compressor or at a higher speed than the constant speed compressor, the reset value is lower than the set target discharge superheat t ₁ , so that the opening value of the electromagnetic expansion valve is adjusted to increase the flow rate of the circulating refrigerant quickly. Even if the inverter compressor is operated at a lower speed than the constant speed compressor, the flow rate of the refrigerant circulating through the multi-type air conditioner can be increased by maintaining the flow rate of the refrigerant sucked into the inverter compressor to prevent overheating of the inverter compressor, and circulating the entire multi-type air conditioner. The increase in heat exchange efficiency increases cooling or heating There is an advantage to increase the room efficiency.

Claims (6)

An inverter compressor for a variable speed drive and a constant speed type compressor for a constant speed drive, A condenser for condensing the refrigerant passing through the inverter compressor or the constant speed compressor; An electronic expansion valve for adjusting a flow rate by adjusting an opening value to reduce the refrigerant passing through the condenser; When the inverter compressor is operated at a lower speed than the constant speed compressor, the inverter discharge superheat degree is reset to prevent the inverter compressor from overheating and the opening value of the electromagnetic expansion valve is adjusted according to the reset target discharge superheat degree. Multi-type air conditioner, characterized in that configured to include a microcomputer. The method of claim 1, The target discharge superheat is set to the microcomputer such that only the inverter compressor is operated or the second target discharge superheat is lower than the first target discharge superheat set when the inverter compressor is operated at a higher speed than the constant speed compressor. Multi-type air conditioner, characterized in that pre-stored. A first step of simultaneously operating the inverter compressor and the constant speed compressor according to the cooling or heating load; A second step of detecting operating speeds of the inverter compressor and the constant speed compressor operated in the first step; And a third step of resetting the target discharge superheat when the inverter compressor is operated at a lower speed than the constant speed type compressor as a result of the detection of the second step. The method of claim 3, wherein The first step may include a first process of setting a first target discharge superheat degree according to the cooling or heating load, and an opening value of the electromagnetic expansion valve according to the first target discharge superheat degree set in the first step. Operation control method of a multi-type air conditioner, characterized in that configured to include two processes. The method of claim 4, wherein And in the third step, the target discharge superheat is reset to a second target discharge superheat lower than the first target discharge superheat. The method of claim 5, wherein The third step is a control method for the operation of the multi-type air conditioner, characterized in that further comprising the step of adjusting the opening value of the electromagnetic expansion valve in accordance with the reset second target discharge superheat degree.