JPH1038422A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid an interruption of heating operation caused by defrosting operation and improve the comfort. SOLUTION: An outdoor heat exchanger that is a component of a refrigerating cycle is divided into first and second outdoor heat exchangers 5 and 7, and a second pressure reducing device 6 is arranged between the first and second heat exchangers 5 and 7. A bypass pipeline 9 with an on-off valve 8 connects a heating operation inlet side pipe of the second pressure reducing device 6 and a heating operation outlet side of the second outdoor heat exchanger 7. During defrosting operation, a first pressure reducing device 4 is opened full, the second pressure reducing device 5 is throttled, and the on-off valve 8 is opened full. Thereby, both first outdoor heat exchanger 5 and indoor heat exchanger 3 serve as condensers and the second outdoor heat exchanger 7 serves as an evaporator, allowing heating operation to be performed while defrosting operation is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly, to a refrigeration cycle for enabling defrosting of an outdoor heat exchanger without interrupting a heating operation, and a control means therefor. .

[0002]

2. Description of the Related Art A refrigeration cycle of an air conditioner is shown in FIG.
As shown in the figure, a compressor 21, a four-way valve 22, and an indoor heat exchanger
23, a pressure reducing device (expansion valve) 24, and an outdoor heat exchanger 25, and the refrigerant discharged from the compressor 21 during the heating operation is a four-way valve 22, an indoor heat exchanger 23, a pressure reducing device ( The expansion valve 24 circulates to the outdoor heat exchanger 25 and returns to the compressor 21 via the four-way valve 22 again. By the way, in the heating operation, condensed water adheres to the outdoor heat exchanger 25 in relation to the outside air temperature, and this condensed water may adversely affect heat exchange.

Therefore, in the conventional air conditioner, when the temperature of the outdoor heat exchanger 25 drops to, for example, -5.degree. C. (defrosting start temperature), the defrosting operation is started. When the temperature rises to + 5 ° C. (defrost release temperature), the defrost operation is terminated, and the operation returns to the heating operation. As a method of the defrosting operation, a so-called reverse method in which the flow of the refrigerant is temporarily changed by switching the four-way valve 22 and a method in which the compressor 21 is used.
A bypass pipe 27 having an on-off valve 26 as shown by a broken line is provided between the discharge side of the outdoor heat exchanger 25 and the inlet side (at the time of heating) of the outdoor heat exchanger 25 so that hot gas flows through the outdoor heat exchanger 25. There is a gas bypass system, and any of these is used.

[0004]

However, when the above-mentioned reverse method is used, heating operation is interrupted due to defrosting, and cooling operation is performed, so that comfort is impaired. When the method is used, there is a problem that not only the heating capacity at the time of defrosting is greatly reduced, but also it takes too much time until the end of the defrosting. Therefore, an object of the present invention is to provide an air conditioner in which these problems are further improved.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and comprises a compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger. In an air conditioner provided with a refrigeration cycle formed by sequentially connecting pipes, the outdoor heat exchanger is separated into a first outdoor heat exchanger and a second outdoor heat exchanger, and the first outdoor heat exchange is performed. A second pressure reducing device is connected between the heat exchanger and the second outdoor heat exchanger, and between the heating-side inlet pipe of the second pressure reducing apparatus and the heating-side outlet pipe of the second outdoor heat exchanger. A bypass line provided with an on-off valve is provided. When the temperature of the first outdoor heat exchanger is equal to or lower than a predetermined value, the first decompression device is fully opened, the second decompression device is throttled, and the on-off valve is closed. The defrosting operation was performed while performing the heating operation by fully closing.

When the outside air temperature during the heating operation is equal to or higher than a predetermined value, the first pressure reducing device is throttled, the second pressure reducing device is fully opened, and the on-off valve is fully closed.

When the outside air temperature during the heating operation is equal to or less than a predetermined value, the first pressure reducing device is throttled, the second pressure reducing device is fully closed, and the on-off valve is fully opened.

During the cooling operation, the first pressure reducing device is throttled, the second pressure reducing device is fully opened, and the on-off valve is fully closed.

The sizes of the first outdoor heat exchanger and the second outdoor heat exchanger are set at a ratio of 5: 1 to 3: 2.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an air conditioner according to the present invention, an outdoor heat exchanger constituting a refrigeration cycle is separated into a first outdoor heat exchanger and a second outdoor heat exchanger. A second pressure reducing device is connected between the first outdoor heat exchanger and the second outdoor heat exchanger, and the heating-side inlet pipe of the second pressure reducing device and the heating-side outlet side of the second outdoor heat exchanger. A bypass line with an on-off valve is provided between the pipe and the first decompression device when the defrosting operation is performed, the second decompression device is fully opened, and the on-off valve of the bypass line is fully closed. I do. This allows
Since the first outdoor heat exchanger can be used as a condenser and the second outdoor heat exchanger can be used as an evaporator, the heating operation can be performed while performing the defrosting operation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 schematically shows a refrigeration cycle of an air conditioner and a control system thereof. 1 is a compressor, 2 is a four-way valve for switching the flow of refrigerant in accordance with an operation mode such as cooling operation or heating operation, 3 Is the indoor heat exchanger, 4 is the first
Decompression device (expansion valve), 5 is a first outdoor heat exchanger, 6 is a second decompression device (expansion valve), 7 is a second outdoor heat exchanger, when the second decompression device 6 is heated. A bypass pipe 9 provided with an on-off valve 8 is provided between the inlet pipe and the outlet pipe during heating of the second outdoor heat exchanger 7. Reference numeral 10 denotes a temperature detection sensor for detecting the temperature of the first outdoor heat exchanger 5, reference numeral 11 denotes an indoor unit control section for controlling an indoor blower, a wind direction adjusting device and the like (not shown), reference numeral 12 denotes a compressor (motor) 1, and four directions. An outdoor unit controller that controls the valve 2, the first decompression device 4, the second decompression device 6, the on-off valve 8, an outdoor blower (not shown), and the like. In the present embodiment, the size of the first outdoor heat exchanger 5 and the size of the second outdoor heat exchanger 7 are approximately 2: 1.

Although not shown, the indoor unit controller 11 and the outdoor unit controller 12 each include an A / D converter for converting an analog signal such as temperature information into a digital signal, a timer unit, and the like.
There are a storage unit, a comparison unit, and the like. The information on the temperature of the first outdoor heat exchanger 5 detected by the temperature detection sensor 10 and the outside air temperature detected by a temperature detection sensor (not shown) is stored in the outdoor unit control unit 12. Input to the A / D converter on the side
The A / D converter on the side of the indoor unit controller 11 has a temperature of the indoor heat exchanger 3 detected by a temperature detection sensor (not shown), an indoor temperature detected by a temperature detection sensor also not shown, and the like. Information is input.

FIG. 2 shows an example of the control operation of the outdoor unit controller 12 according to the present invention. In the cooling operation, the first expansion valve 4 is used as a pressure reducing device, and the second expansion valve (pressure reducing device) is used.
6 is fully open, and the on-off valve 8 is fully closed. As a result, the second outdoor heat exchanger 7 and the first outdoor heat exchanger 5 both act as condensers.

The outside air temperature is relatively high (for example, 7 ° C.).
During the normal heating operation performed at the time of the above), there is no possibility that the first outdoor heat exchanger 5 freezes, so the first expansion valve 4 is used as a pressure reducing device, and the second expansion valve (pressure reducing device) 6 is fully opened. The on-off valve 8 is fully closed. As a result, the second outdoor heat exchanger 7 and the first outdoor heat exchanger 5 both act as evaporators.

Further, the outside air temperature drops to, for example, 7 ° C. or less,
At the time of low-temperature heating performed when the first outdoor heat exchanger 5 is in a state where ice is easily formed, the first expansion valve 4 is used as a decompression device,
The second expansion valve 6 is fully closed, and the on-off valve 8 is fully open. Thereby, the first outdoor heat exchanger 5 functions as an evaporator, and the second outdoor heat exchanger 7 is in an unused state. When the defrosting operation is required due to a decrease in outside air temperature, the first expansion valve 4 is fully opened, the second expansion valve 6 is used as a pressure reducing device, and the on-off valve 8 is fully closed. . As a result, the indoor heat exchanger 3 and the first outdoor heat exchanger 5 act as a condenser, and the second outdoor heat exchanger 7 acts as an evaporator, so that the first outdoor heat exchanger 5 And the heating by the second outdoor heat exchanger 7 are performed at the same time. In addition,
In the present embodiment, after the defrosting of the first outdoor heat exchanger 5 is completed, the second expansion valve 6 is temporarily opened to perform the defrosting of the second outdoor heat exchanger 7.

[0016]

According to the air conditioner described above, a certain amount of warm air can be sent from the indoor unit even during the defrosting operation, so that the room temperature does not suddenly decrease.
Comfort is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a refrigeration cycle and a control system thereof according to the present invention.

FIG. 2 is a diagram illustrating a control operation example on the outdoor unit control unit side according to the present invention.

FIG. 3 is a block diagram schematically showing a conventional refrigeration cycle and its control system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Indoor heat exchanger 4 1st decompression device (expansion valve) 5 1st outdoor heat exchanger 6 2nd decompression device (expansion valve) 7 2nd outdoor heat exchanger 8 On-off valve 9 Bypass line 10 Temperature detection sensor 11 Indoor unit control unit 12 Outdoor unit control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location F24F 11/02 101 F24F 11/02 101K

Claims (5)

[Claims] 1. A compressor, a four-way valve, an indoor heat exchanger,
In an air conditioner provided with a refrigeration cycle in which a pressure reducing device and an outdoor heat exchanger are sequentially connected by piping, the outdoor heat exchanger is divided into a first outdoor heat exchanger and a second outdoor heat exchanger. Separating and connecting a second decompression device between the first outdoor heat exchanger and the second outdoor heat exchanger, heating the inlet-side pipe of the second decompression device and the second outdoor heat exchanger A bypass pipe provided with an on-off valve between the heating-side outlet pipe and the first outdoor heat exchanger, when the temperature of the first outdoor heat exchanger is equal to or lower than a predetermined value, fully open the first pressure reducing device; Squeeze the decompression device of
An air conditioner characterized by performing a defrosting operation while performing a heating operation by fully closing the on-off valve. 2. When the outside air temperature during the heating operation is equal to or higher than a predetermined value, the first pressure reducing device is throttled, the second pressure reducing device is fully opened, and the on-off valve is fully closed. Item 7. The air conditioner according to Item 1. 3. When the outside air temperature during the heating operation is equal to or lower than a predetermined value, the first pressure reducing device is throttled, the second pressure reducing device is fully closed, and the on-off valve is fully opened. Item 7. The air conditioner according to Item 1. 4. The air conditioner according to claim 1, wherein during cooling operation, the first pressure reducing device is throttled, the second pressure reducing device is fully opened, and the on-off valve is fully closed. 5. The air conditioner according to claim 1, wherein the size of the first outdoor heat exchanger and the size of the second outdoor heat exchanger are 5: 1 to 3: 2.