JPH09264614A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of the cycle for a wider range of load by providing a controlling means for switching refrigerant channels to after the number of paths at least in one of the indoor and outdoor heat exchangers according as the air-conditioning load. SOLUTION: In a refrigeration cycle comprising a compressor 1, four-way valve 2, outdoor heat exchanger 3, pressure reducer 4, and indoor heat exchanger 5 all connected by piping the outdoor heat exchanger 3 has refrigerant channels 3a, 3b in a constitution enabling the refrigerant channels 3a, 3b to be switched to a state of one path or to a state of two paths by three-way valves 6a, 6b. Likewise the indoor heat exchanger 5 has refrigerant channels 5a, 5b and three-way valves 7a, 7b an permits the refrigerant channels to be switched to a state of one path or to a state of two paths. For example, while for cooling the indoor heat exchanger 5 is at work with two paths in use and the outdoor heat exchanger 3, with one path in use and the operation is being conducted at a rated capacity and when the air-conditioning load decreases to a lower load, the indoor heat exchanger 5 is operated with one path in use and the outdoor heat exchanger 3, with one path so that the deterioration of the efficiency of the cycle can be moderated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to switching control of a refrigerant flow path of an air conditioner.

[0002]

2. Description of the Related Art As shown in FIG. 7, an air conditioner is a refrigeration cycle in which a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a decompressor 4, and an indoor heat exchanger 5 are connected by piping to circulate a refrigerant. Are configured.

Japanese Utility Model Publication No. 7-32460 discloses the following air conditioner. In this air conditioner, the four-way valve 2 is switched for switching between the cooling operation and the heating operation and the direction of the refrigerant flowing through the indoor heat exchanger 5 is reversed, so that the indoor heat exchanger is operated during the heating operation. 5 is operated in one pass, and the indoor heat exchanger 5 is operated in two passes during the cooling operation so that both the cooling operation and the heating operation can be efficiently operated.

[0004]

As described above, by switching the number of paths of the indoor heat exchanger 5 according to the operation mode, the efficiency in the cooling operation and the heating operation in the rated condition can be improved. Under the current operating conditions, it is not possible to expect improvement in efficiency.

An object of the present invention is to provide an air conditioner capable of not only improving the efficiency during cooling operation and heating operation under rated conditions but also improving the efficiency under operating conditions outside the rated conditions. .

[0006]

An air conditioner according to claim 1 is an air conditioner in which a refrigeration cycle is formed by interposing an indoor heat exchanger and an outdoor heat exchanger, and the indoor heat exchanger. And a heat exchanger of at least one of the outdoor heat exchanger, the refrigerant passage switching control means for changing the number of paths according to the magnitude of the air conditioning load.

An air conditioner according to a second aspect of the present invention is an air conditioner in which a refrigerating cycle is formed by interposing an indoor heat exchanger and an outdoor heat exchanger, and an operation mode indicating a cooling operation and a heating operation. A refrigerant flow path switching control means for changing the number of passes of the indoor heat exchanger and the outdoor heat exchanger according to the above is provided.

The air conditioner according to a third aspect of the present invention is the air conditioner according to the first aspect, in which the refrigerant flow path switching control means determines the number of paths of the heat exchanger based on the operation mode indicating the cooling operation and the heating operation and the refrigerant circulation amount. It is characterized by changing.

The air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first aspect, wherein the refrigerant flow path switching control means includes the number of revolutions of the compressor interposed in the refrigeration cycle, an operating current value, an evaporator temperature, and an evaporator. It is characterized in that the number of passes of the heat exchanger is changed based on at least one of the unit pressure and the suction pressure of the compressor, and the operation mode representing the distinction between the cooling operation and the heating operation.

The air conditioner according to a fifth aspect of the present invention is the air conditioner according to the first aspect, wherein the refrigerant flow path switching control means during the cooling operation operates the indoor heat exchanger with two passes when the air conditioning load has a rated output.
When the outdoor heat exchanger is operated in one pass, the indoor heat exchanger and the outdoor heat exchanger are both operated in one pass when the air conditioning load is small, and the indoor heat exchanger and the outdoor heat exchanger are both operated when the air conditioning load is large. It is characterized by driving on a pass.

The air conditioner according to a sixth aspect of the present invention is the air conditioner according to the first aspect, wherein the refrigerant flow path switching control means during the heating operation operates the indoor heat exchanger in one pass when the air conditioning load has a rated output.
When the outdoor heat exchanger is operated in two passes, the indoor heat exchanger and the outdoor heat exchanger are both operated in one pass when the air conditioning load is small, and the indoor heat exchanger and the outdoor heat exchanger are both operated when the air conditioning load is large. It is characterized by driving on a pass.

The air conditioner according to a seventh aspect of the present invention is the air conditioner according to the first aspect, wherein the refrigerant flow path switching control means is responsive to an operation mode indicating a distinction between the cooling operation and the heating operation during the cooling operation and the magnitude of the air conditioning load. , When the air conditioning load is the rated output, the indoor heat exchanger is operated in two passes, the outdoor heat exchanger is operated in one pass, and when the air conditioning load decreases, both the indoor heat exchanger and the outdoor heat exchanger are in one pass. When the air conditioning load increases, both the indoor heat exchanger and the outdoor heat exchanger are operated in two passes, and during the heating operation, depending on the operation mode indicating the distinction between the cooling operation and the heating operation and the magnitude of the air conditioning load, When the air conditioning load is the rated output, the indoor heat exchanger is operated in one pass, the outdoor heat exchanger is operated in two passes, and when the air conditioning load is small, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass. However, if the air conditioning load increases, the indoor heat Characterized by operating at both 2 pass exchanger and the outdoor heat exchanger.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an air conditioner according to the present invention will be described below with reference to FIGS. As shown in FIG. 1, a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a decompressor 4, and an indoor heat exchanger 5 are connected by piping to constitute a refrigeration cycle in which a refrigerant circulates.

The outdoor heat exchanger 3 has refrigerant flow paths 3a and 3b, and the three-way valves 6a and 6b allow the refrigerant flow paths 3a and 3b.
It is configured so that b can be switched between a one-pass state and a two-pass state.

Like the outdoor heat exchanger 3, the indoor heat exchanger 5 also has refrigerant flow paths 5a and 5b and three-way valves 7a and 7b.
It is configured to switch between a one-pass state and a two-pass state.

The three-way valves 6a, 6b, 7a and 7b are control units 8
According to the operation mode and the magnitude of the air conditioning load, switching is performed according to the table A shown in FIG. In this embodiment, the refrigerant flow path switching control means in the claims is composed of three-way valves 6a, 6b, 7a, 7b and a control unit 8.

The control unit 8 composed of a microcomputer executes the flow shown in FIG. 3 when the operation mode is the cooling operation, and executes the flow shown in FIG. 4 when the operation mode is the heating operation. It is configured. When the user sets the cooling operation or the heating operation with the setting switch, the operating mode being executed is determined based on the contents read from the setting switch, and the user automatically uses the setting switch. When the operation is selected, the necessary operation mode is automatically determined based on the temperature difference between the indoor target temperature and the indoor suction temperature.

First, based on the flow shown in FIG. 3, how the number of paths of each of the outdoor heat exchanger 3 and the indoor heat exchanger 5 is switched by the control unit 8 in accordance with the magnitude of the air conditioning load during the cooling operation. Explain if it can be done. The compressor 1
Is automatically controlled in its rotation speed so that the room temperature approaches the target temperature based on the detection values of various sensors (not shown).

The control unit 8 collects the operation data necessary for judging the present magnitude of the air conditioning load in [Step 1] shown in FIG. 3 (hereinafter, "Step" is represented by # in the drawing). Specifically, the rotation speed of the compressor 1 is read as a sample value.

In [Step 2], the sample value read in [Step 1] is compared with a reference value to determine the magnitude of the current air conditioning load. In the embodiment shown in FIGS. 2 and 3,
Compared to the standard value, the rated conditions are "rated capacity", "intermediate capacity" of 1/2 of rated capacity, "low capacity" with a small air conditioning load, and "high capacity" with a larger air conditioning load than the rated capacity. Which one it belongs to is determined.

The "rated capacity" means JIS condition "C9".
It is a capacity classification determined by “612-19XX” and refers to a capacity rank determined by the configuration of the air conditioner and its cooling system.

If it is determined in step 2 that the current air conditioning load is "rated capacity" from the number of revolutions of the compressor 1, step 3 is executed and table A shown in FIG. The outdoor heat exchanger 3 is switched to the 1-pass state, and the indoor heat exchanger 5 is switched to the 2-pass state to operate. The switching state of the three-way valves 6a, 6b, 7a, 7b and the flow of the refrigerant in this case are shown in FIG. The arrow indicates the flow direction of the refrigerant.

In FIG. 5A, the compressed refrigerant sent from the compressor 1 is transferred from the three-way valve 6a to the refrigerant pipe 3c and the three-way valve 6.
It flows through the refrigerant flow path 3a of the outdoor heat exchanger 3 via b, and again flows through the refrigerant flow path 3b of the outdoor heat exchanger 3. Then, via the pressure reducing valve 4, the refrigerant flow path 5a of the indoor heat exchanger 5 and the three-way valve 7a
And returns to the compressor 1 via the four-way valve 2. In the indoor heat exchanger 5, the refrigerant flows through the refrigerant flow path 5b via the three-way valve 7b and returns to the compressor 1 via the three-way valve 7a and the four-way valve 2.

When it is determined in [Step 2] that the air conditioning load has changed to, for example, "low capacity" while repeatedly executing [Step 1] to [Step 3] in FIG. 3, execute [Step 3]. Without executing [Step 4], the three-way valves 7a and 7b are switched to switch the indoor heat exchanger 5 to the one-pass state as shown in FIG. Realize improvement.

The improvement of cycle performance by switching the path of the indoor heat exchanger 5 will be described based on the characteristic diagrams shown in FIGS. 6 (a) and 6 (b). 6A shows the relationship between the refrigerant flow rate in the heat exchanger and the thermal conductivity in the tube, and FIG. 6B shows the relationship between the refrigerant flow rate and the pressure loss. What is important here is the difference in the slope of the characteristic line. Refrigerant flow rate is first flow rate 9a
From the above, when the increase is changed to the second flow rate 9b, the change Δα in the heat transfer efficiency in the pipe and the change Δβ in the pressure loss are larger in Δβ than in Δα.

During the cooling operation, the indoor heat exchanger 5 and the outdoor heat exchanger 3 are based on the actual ph diagram and the indoor heat exchanger 5 is used.
Is operated in two passes and the outdoor heat exchanger 3 is operated in one pass to optimize cycle performance.

When the air conditioning load changes to a low load during operation at the rated capacity, the rotational speed of the compressor 1 decreases, the refrigerant flow rate decreases, and the accompanying pressure loss also becomes small. [Step 4] is executed so as to prioritize the rate to operate the indoor heat exchanger 5 in one pass and the outdoor heat exchanger 3 in one pass to reduce deterioration of cycle performance. [Step 2]
When it is determined that the ability is intermediate, the step 5 is executed, and when it is determined that the ability is high, the step 6 is executed.

Therefore, when the operation mode is the heating operation as in the prior art, both the outdoor heat exchanger and the indoor heat exchanger are operated in the 1-pass state, and in the cooling operation, the outdoor heat exchanger is in the 1-pass state and the indoor heat exchange is performed. Current Season Energy Efficiency (SEER) compared to an air conditioner that operates a two-pass conditioner
It is possible to improve the cooling SEER based on the evaluation criteria.

SEER is a Japanese Industrial Standard,
It is stipulated that the energy consumption efficiency (CSPF) in the cooling period and the energy consumption efficiency (HSPF) in the heating period determine.

The operation mode is the heating operation (the four-way valve 2 is shown in FIG.
Is switched to the position indicated by the broken line in FIG.
In [Step 7] shown in FIG. 4, the operation data necessary for judging the current air conditioning load is collected. Specifically, the rotation speed of the compressor 1 is read as a sample value.

In [Step 8], the sample value read in [Step 7] is compared with the reference value to determine the current air conditioning load. Here, compared to the standard value, the rated condition is "rated capacity", "intermediate capacity" of 1/2 of rated capacity, "low capacity" with small air conditioning load, and "large capacity" with air conditioning load larger than rated capacity. Which of the "high abilities" it belongs to is determined.

When it is determined in step 8 that the current air conditioning load is "rated capacity" from the number of revolutions of the compressor 1, step 9 is executed and table A shown in FIG. The outdoor heat exchanger 3 is switched to the 2-pass state, and the indoor heat exchanger 5 is switched to the 1-pass state to operate.

If it is determined in step 8 that the air conditioning load has changed to, for example, "low capacity" while repeatedly executing [step 7] to [step 9] in FIG. 4, execute [step 9]. Instead, [Step 10] is executed to switch the three-way valves 6a and 6b to switch the indoor heat exchanger 3 to the one-pass state and improve the cycle performance. If it is judged that the intermediate ability is obtained in [Step 8], [Step 1
1] is executed, and if it is determined that the ability is high in [Step 8], [Step 12] is executed. When it is determined that the heating temperature is low in [Step 8], [Step 13] is executed.

Therefore, when the operation mode is the heating operation as in the prior art, both the outdoor heat exchanger and the indoor heat exchanger are operated in the 1-pass state, and in the cooling operation, the outdoor heat exchanger is in the 1-pass state and the indoor heat exchange is performed. Current Season Energy Efficiency (SEER) compared to an air conditioner that operates a two-pass conditioner
It is possible to improve the heating SEER based on the evaluation criteria.

In the above embodiment, the three-way valves 6a, 6b, 7a, 7b are provided so that the number of paths of both the outdoor heat exchanger 3 and the indoor heat exchanger 5 can be switched, but the outdoor heat exchanger 3 Is a one-pass state, the indoor heat exchanger 5 is a three-way valve 7a,
7b is provided to switch the three-way valves 7a and 7b according to the air conditioning load to switch the number of passes of the indoor heat exchanger 5 in the cooling operation, or the indoor heat exchanger 5 is in only one pass state and the outdoor heat exchanger 3 is three-way. Even if the valves 6a and 6b are provided and the three-way valves 6a and 6b are switched according to the air conditioning load in the cooling operation to switch the number of paths of the outdoor heat exchanger 3, the cycle performance can be improved as compared with the conventional case.

In each of the above embodiments, the control unit 8 detects the air conditioning load (refrigerant circulation amount) from time to time based on the operation mode and the number of revolutions of the compressor 1. Even if the air conditioning load is determined from the above, the same effect can be expected.

-Estimating the number of revolutions of the compressor from the value of the power supply current-Suction pressure of the compressor-Temperature of the evaporator In each of the above embodiments, the number of passes of the outdoor heat exchanger 3 and the indoor heat exchanger 5 The switching is performed in the one-pass state and the two-pass state, but may be performed in the two-pass state and the four-pass state, and is not limited to the switching between the one-pass state and the two-pass state.

[0038]

According to the first aspect of the present invention, there is provided an air conditioner in which a refrigeration cycle is formed by interposing an indoor heat exchanger and an outdoor heat exchanger, wherein the indoor heat exchanger and the outdoor heat exchanger are Since the refrigerant flow path switching control means for changing the number of paths of at least one of the heat exchangers according to the magnitude of the air conditioning load is provided, in the cooling operation, one path is used for the outdoor heat exchanger and two paths are used for the indoor heat exchanger. It is possible to improve the cycle performance in a wider area as compared with the conventional air conditioner that is only operated at.

According to the second aspect of the present invention, there is provided an air conditioner in which a refrigeration cycle is formed by interposing an indoor heat exchanger and an outdoor heat exchanger, depending on an operation mode indicating a cooling operation and a heating operation. Since the refrigerant flow path switching control means for changing the number of paths of the indoor heat exchanger and the outdoor heat exchanger is provided, the path of one of the indoor heat exchanger and the outdoor heat exchanger is changed according to the operation mode. It is possible to improve the cycle performance in a wider area as compared with the conventional air conditioner in which only the number is changed.

According to the third aspect of the present invention, the refrigerant flow path switching control means of the first aspect changes the number of passes of the heat exchanger based on the operation mode indicating the cooling operation and the heating operation and the refrigerant circulation amount. With this configuration, it is possible to improve the refrigeration cycle performance in a wider area by determining the number of passes of the heat exchanger according to the operation mode and the refrigerant circulation amount.

According to the structure of claim 4, the refrigerant flow path switching control means of claim 1 is provided with the number of revolutions of the compressor, the operating current, the evaporator temperature, the evaporator pressure, and the compressor installed in the refrigeration cycle. Since the number of passes of the heat exchanger is changed based on at least one of the suction pressure of the heat exchanger and the operation mode, the refrigerant circulation amount can be estimated without directly measuring the refrigerant circulation amount to simplify the device. Can be realized.

According to the fifth aspect of the present invention, the refrigerant flow path switching control means of the first aspect causes the indoor heat exchanger to operate in two passes when the air conditioning load is at the rated output during the cooling operation. If the air conditioning load is small, the indoor heat exchanger and the outdoor heat exchanger are both operated in one pass, and if the air conditioning load is large, the indoor heat exchanger and the outdoor heat exchanger are both in two passes. Since it is configured to operate, cooling SE based on the current evaluation criteria of season energy efficiency (SEER)
ER can be improved.

According to the sixth aspect of the present invention, the refrigerant flow path switching control means of the first aspect causes the indoor heat exchanger to operate in one pass when the air conditioning load is at the rated output during the heating operation. When the air conditioner load is small, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass, and when the air conditioning load is large, both the indoor heat exchanger and the outdoor heat exchanger are operated in two passes. Since it is configured to operate, the heating SEER can be improved in the current season energy efficiency (SEER).

According to a seventh aspect of the present invention, the refrigerant flow path switching control means of the first aspect is provided with an air conditioning load in accordance with the operation mode indicating the cooling operation and the heating operation during the cooling operation and the magnitude of the air conditioning load. When the rated output is, the indoor heat exchanger is operated in two passes, the outdoor heat exchanger is operated in one pass, and when the air conditioning load decreases, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass, When the air conditioning load increases, both the indoor heat exchanger and the outdoor heat exchanger are operated in two passes, and during the heating operation, the air conditioning load changes according to the operation mode that indicates the distinction between cooling operation and heating operation and the air conditioning load. When the rated output is reached, the indoor heat exchanger is operated in one pass, the outdoor heat exchanger is operated in two passes, and when the air conditioning load decreases, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass, and air conditioning is performed. When the load increases, the indoor heat exchanger and the outdoor For configuring the exchanger together to operate in two passes, the current season energy efficiency (SE
ER), the SEER of cooling and heating can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an air conditioner of the present invention.

FIG. 2 is an explanatory diagram of a table of a control unit according to the same embodiment.

FIG. 3 is a flowchart of a control unit during the cooling operation of the same embodiment.

FIG. 4 is a flowchart of a control unit during the heating operation according to the same embodiment.

FIG. 5 is an explanatory diagram of a refrigerant path in the number of paths switching state during cooling operation of the embodiment.

FIG. 6 is a relational diagram of the refrigerant flow rate, the heat transfer coefficient in the pipe, and the pressure loss.

FIG. 7 is a configuration diagram of a conventional air conditioner.

[Explanation of symbols]

 1 compressor 2 four-way valve 3 outdoor heat exchanger 4 pressure reducer 5 indoor heat exchanger 6a, 6b three-way valve 7a, 7b three-way valve 8 control unit A table

Front page continued (72) Inventor Yuichi Yakumaru 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Akira Fujitaka 1006 Kadoma, Kadoma City, Osaka (72) Invention Yukio Watanabe 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 1006 Kadoma, Oita-shi Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. An air conditioner in which a refrigeration cycle is formed by interposing an indoor heat exchanger and an outdoor heat exchanger, wherein at least one of the indoor heat exchanger and the outdoor heat exchanger is a heat exchanger. An air conditioner provided with a refrigerant flow path switching control means for changing the number of passes according to the magnitude of the air conditioning load. 2. An air conditioner in which a refrigeration cycle is formed by interposing an indoor heat exchanger and an outdoor heat exchanger, wherein the indoor heat exchanger is selected according to an operation mode indicating distinction between cooling operation and heating operation. And an air conditioner provided with a refrigerant flow path switching control means for changing the number of passes of the outdoor heat exchanger. 3. The air conditioner according to claim 1, wherein the refrigerant flow path switching control means changes the number of paths of the heat exchanger based on an operation mode representing a distinction between cooling operation and heating operation and a refrigerant circulation amount. 4. The refrigerant flow path switching control means is at least one of the number of revolutions of a compressor installed in the refrigeration cycle, an operating current value, an evaporator temperature, an evaporator pressure, and a suction pressure of the compressor. The air conditioner according to claim 1, wherein the number of paths of the heat exchanger is changed based on one of the operation mode indicating the cooling operation and the operation mode indicating the heating operation. 5. The refrigerant flow path switching control means during the cooling operation,
When the air conditioning load is the rated output, the indoor heat exchanger is operated in two passes, the outdoor heat exchanger is operated in one pass, and when the air conditioning load decreases, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass. The air conditioner according to claim 1, wherein both the indoor heat exchanger and the outdoor heat exchanger are operated in two passes when the air conditioning load increases. 6. The refrigerant flow path switching control means during the heating operation,
When the air conditioning load is the rated output, the indoor heat exchanger is operated in one pass, the outdoor heat exchanger is operated in two passes, and when the air conditioning load is small, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass. The air conditioner according to claim 1, wherein both the indoor heat exchanger and the outdoor heat exchanger are operated in two passes when the air conditioning load increases. 7. The refrigerant flow path switching control means, when the air conditioning load is at the rated output, in accordance with the operation mode representing the distinction between the cooling operation and the heating operation during the cooling operation and the magnitude of the air conditioning load, the indoor heat exchanger. Is operated in two passes, the outdoor heat exchanger is operated in one pass, both the indoor heat exchanger and the outdoor heat exchanger are operated in one pass when the air conditioning load decreases, and the indoor heat exchanger operates when the air conditioning load increases. Both the outdoor heat exchanger is operated in two passes, and during heating operation, the indoor heat exchanger is operated when the air conditioning load is at the rated output according to the operation mode that indicates the distinction between cooling operation and heating operation and the air conditioning load. Operate in 1 pass, operate outdoor heat exchanger in 2 passes, operate both indoor heat exchanger and outdoor heat exchanger in 1 pass when air conditioning load is small, and operate indoor heat exchanger and outdoor when air conditioning load is large. Contract to operate both heat exchangers in two passes The air conditioner according to claim 1.