JP2007212077A - Air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air-conditioner having refrigerant collecting operation for accurately collecting refrigerant while protecting a compressor. <P>SOLUTION: On the shell of the compressor 1, a thermistor 7 is provided for detecting the temperature of the shell. During cooling or heating operation when a refrigerant leak sensor 8 for an indoor heat exchanger 5 detects the leak of refrigerant, refrigerant collecting operation is started to collect the refrigerant from the indoor side to the outdoor side. When the temperature of the shell of the compressor rises and the detected temperature of the thermistor 7 mounted on the surface of the shell is higher than a preset temperature, the refrigerant is determined to be sufficiently collected and the refrigerant collecting operation is finished. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner, and more specifically, when there is a risk of refrigerant leaking from an indoor heat exchanger or a pipe connected to the indoor heat exchanger, the refrigerant is quickly collected and the refrigerant leaks into the room. Concerning the prevented configuration.

  For example, an air conditioner 30 as shown in FIG. 4A has been proposed as a conventional technique for recovering the refrigerant in the refrigerant circuit in order to prevent refrigerant leakage. The air conditioner 30 configures a refrigerant circuit by sequentially connecting a compressor 31, a four-way valve 32, an outdoor heat exchanger 33, an expansion valve 34, and an indoor heat exchanger 35, and the expansion valve 34 and the indoor A liquid side on / off valve 36 such as an electromagnetic on / off valve is provided between the heat exchanger 35 and a gas side on / off valve 37 such as an electromagnetic on / off valve is provided between the indoor heat exchanger 35 and the four-way valve 32. Yes. The indoor unit 30b includes a first leak sensor 38 that detects refrigerant leakage, the outdoor unit 30a includes a second leak sensor 40, and the pipe 30c that connects the indoor unit 30b and the outdoor unit 30a includes a third leak sensor. 39 is provided (see Patent Document 1).

  When the refrigerant leaks from these due to deterioration of piping and equipment, and any of the first leak sensor 38, the second leak sensor 40, and the third leak sensor 39 detects the refrigerant leak, The four-way valve 32 is switched, and first the cooling operation is started. Next, the liquid side on-off valve 36 is closed, and then the refrigerant in the indoor heat exchanger 35 and the piping is sucked into the compressor 31 through the four-way valve 32 and from the compressor 31 to the above-mentioned The heat is sent to the outdoor heat exchanger 33 and collected in the outdoor heat exchanger 33.

  The refrigerant recovery operation to the outdoor heat exchanger 33 is continued for a predetermined time set in advance. When the predetermined time elapses, it is considered that all the refrigerant has been recovered, and the gas side on-off valve 37 is operated. Is closed and the compressor 31 is stopped.

  However, performing the refrigerant recovery operation for a predetermined time set in advance does not necessarily mean that all the refrigerant is recovered within the predetermined time, and the refrigerant recovery operation may be stopped in an unrecovered state. there were. On the other hand, the refrigerant recovery operation may be continued even though all the refrigerant has been recovered. In such a case, the compressor 31 is operated in a state where there is no refrigerant to be sucked. The lubrication and cooling action by the refrigerant in the compressor 31 is not performed, and there is a possibility that troubles may occur in the internal equipment.

  As another conventional example, an air conditioner 50 shown in FIG. 4B is presented. When the air conditioner is relocated or removed, a pump-down operation is performed to collect the refrigerant staying in the indoor side and the pipe outside, and the air conditioner 50 is shown below in preparation for the pump-down operation. Thus, the refrigerant circuit and the control unit are configured. The dotted line 51 is the outdoor side, and the dotted line 52 is the indoor side. The refrigerant circuit is configured by sequentially connecting a compressor 53, an outdoor heat exchanger 54, a discharge pipe service valve 55, an indoor heat exchanger 56, a suction pipe service valve 57, and a refrigerant pressure detector 21, and the compressor 53 A power source 59 is connected via a switch 60 (see Patent Document 2).

  The control unit includes a pump down operation control unit 61. The pump down operation control unit 61 includes a switch control unit 62, a time measuring unit 63, a pump down predetermined time setting unit 64, and a pump down time comparison. Means 65 is provided, and a receiver that receives the start of pump down operation, the refrigerant pressure detector, an outside air temperature detector that detects outside air temperature, and the switch are connected.

  When the receiver receives an instruction to start pump down operation, the pump down predetermined time setting means 64 is based on the outside air temperature detected by the outside air temperature detector and the refrigerant temperature detected by the refrigerant pressure detector. A predetermined time for pumping down is set. As a result, an accurate pump-down operation can be performed regardless of changes in the refrigerant state caused by the outside air temperature or the like.

  However, there is a problem that the installation of the refrigerant pressure detector and the like is required, and the control system becomes slightly complicated, resulting in an increase in cost.

JP-A-6-180166 (page 2-4, FIG. 1) Japanese Unexamined Patent Publication No. 2000-161798 (page 2-4, FIG. 1)

  In view of the above problems, the present invention can accurately recover the refrigerant to the outdoor side during refrigerant leakage or pump-down operation, ensure the safety of the compressor, and reduce the cost. The purpose is to provide a machine.

  In order to solve the above-described problems, the present invention provides an air conditioner in which a compressor, an outdoor heat exchanger, a decompression unit, and an indoor heat exchanger are sequentially connected to form a refrigerant circuit. In the refrigerant recovery operation in which the temperature detection means is provided in the shell and the refrigerant is recovered from the indoor side to the outdoor side, the compression is performed when the temperature detected by the temperature detection means becomes higher than a predetermined temperature. The machine is stopped and the refrigerant recovery operation is terminated. Further, in an air conditioner configured by sequentially connecting a compressor, an outdoor heat exchanger, a decompression unit, and an indoor heat exchanger to form a refrigerant circuit, a temperature detection unit is provided in the shell of the compressor, The temperature of the shell is measured at the start of the refrigerant recovery operation for recovering the refrigerant from the indoor side to the outdoor side, and the temperature detected by the temperature detecting means during the recovery operation is higher than the shell temperature by a predetermined temperature or more. Then, the compressor is stopped and the refrigerant recovery operation is terminated.

  According to the present invention, during the cooling or heating operation, when the refrigerant leak sensor of the indoor heat exchanger detects the leakage of the refrigerant, the cooling operation is started, and the refrigerant recovery operation for recovering the refrigerant from the indoor side to the outdoor side is started. It has come to be. The refrigerant in the indoor heat exchanger decreases, and the refrigerant is not sufficiently sucked into the compressor, so that the compressor shell temperature rises, and the detection temperature of the thermistor attached to the shell surface is set to a predetermined value. When the temperature is higher than the temperature, it is determined that the refrigerant has been sufficiently recovered, and the refrigerant recovery operation ends. As a result, the leakage of the refrigerant can be prevented accurately, while the occurrence of trouble in the equipment inside the compressor due to insufficient lubrication and cooling can be prevented. Further, this makes it possible to provide an air conditioner that can simplify the control system and reduce the cost.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail as examples based on the attached drawings.

  FIG. 1 is a refrigerant circuit diagram of an air conditioner according to the present invention, and FIG. 2 is a flowchart in the refrigerant recovery operation in the first embodiment. FIG. 3 is a flowchart for the refrigerant recovery operation in the second embodiment.

  As shown in FIG. 1, the air conditioner according to the present invention has a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, and an indoor heat exchanger 5 sequentially connected by piping. A refrigerant circuit is provided, and a liquid-side on-off valve 6a such as an electromagnetic on-off valve is provided between the expansion valve 4 and the indoor heat exchanger 5, and between the indoor heat exchanger 5 and the four-way valve 2 is provided. A gas side on / off valve 6b is provided by an electromagnetic on / off valve or the like. The liquid side on / off valve 6a and the gas side on / off valve 6b are normally open.

  The indoor heat exchanger 5 is provided with a refrigerant leak sensor 8 that detects when refrigerant leaks from the indoor heat exchanger 5. The compressor 1 includes a metallic shell serving as a hermetic container and a compression portion housed in the shell, and a thermistor 7 for detecting the temperature of the shell is provided on the shell surface. A plurality of refrigerant leak sensors 8 may be provided not only in the outdoor heat exchanger 5 but also in the refrigerant circuit.

  During the cooling operation, the high-temperature and high-pressure refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 3 through the four-way valve 2. The refrigerant that has flowed into the outdoor heat exchanger 3 releases heat to the surroundings and condenses, and is then throttled by the expansion valve 4 to adiabatically expand to a low temperature and low pressure. The low-temperature and low-pressure refrigerant then flows into the indoor heat exchanger 5, and evaporates by absorbing heat from the air flowing around the indoor heat exchanger 5. The evaporated refrigerant is returned to the compressor 1 through the four-way valve 2. During the heating operation, the four-way valve 2 is switched, and the high-temperature and high-pressure refrigerant discharged from the compressor 1 flows into the indoor heat exchanger 5 through the switched four-way valve 2. The refrigerant flowing into the indoor heat exchanger 5 releases heat to the surrounding air and condenses, and is then throttled by the expansion valve 4 to adiabatically expand to a low temperature and low pressure. The refrigerant that has become low temperature and low pressure then flows into the outdoor heat exchanger 3 and absorbs heat in the outdoor heat exchanger 3 to evaporate. The evaporated refrigerant is returned to the compressor 1 through the four-way valve 2.

  When the refrigerant is not sucked into the compressor 1 during the refrigerant recovery operation, lubrication and cooling of the compression part by the refrigerant are not performed, so that the temperature of the shell as the sealed container rises together with the compression part. Although not shown in the drawings, the control unit of the air conditioner is set to a predetermined temperature within a range in which no trouble occurs in the compressor 1 when the shell temperature of the compressor 1 rises. .

  Next, the operation during the refrigerant recovery operation will be described. As shown in the flowchart of FIG. 2, during cooling or heating operation, when the refrigerant leak sensor 8 provided in the indoor heat exchanger 5 detects leakage of refrigerant (STEP 1), the cooling operation is continued in the cooling operation. In the heating operation, the four-way valve 2 is switched to shift to the cooling operation (STEP 2). Next, the liquid side on-off valve 6a is closed to prevent the refrigerant from flowing from the outdoor heat exchanger 3 into the indoor heat exchanger 5 (STEP 3).

  The operation of the compressor 1 is continued, and the refrigerant in the indoor heat exchanger 5 and the refrigerant in the pipe are sucked into the suction side of the compressor 1 through the four-way valve 2, and then the compressor 1 It is discharged from the discharge side and flows into the outdoor heat exchanger 3 through the four-way valve 2. The refrigerant that has flowed in is sequentially accumulated in the outdoor heat exchanger 3 by closing the liquid side on-off valve 6a (STEP 4).

  When the refrigerant in the indoor heat exchanger 5 decreases and the refrigerant is not sufficiently sucked into the compressor 1, lubrication and cooling by the refrigerant are not performed, so that the compression portion and the shell temperature gradually increase. The detected temperature of the thermistor 7 attached to the shell surface is compared with a predetermined temperature set in advance (STEP 5). When the detected temperature becomes higher than the predetermined temperature, it is determined that the refrigerant has been sufficiently recovered, and the gas side on-off valve 6b. Is closed (STEP 6), the compressor 1 is stopped, and the refrigerant recovery operation is terminated. Thereby, while the refrigerant | coolant leakage from an air conditioner is prevented correctly, the refrigerant | coolant collection | recovery driving | operation which can prevent generating a trouble in the equipment inside the said compressor 1 by lack of lubrication and cooling can be performed now. In the pump down operation, the refrigerant recovery operation can be performed in the same manner.

  Next, a second embodiment will be described based on the flowchart of FIG. In the second embodiment, the shell temperature of the compressor 1 is measured at the start of the refrigerant recovery operation, and a certain predetermined temperature indicating how many times the measured shell temperature has been raised is set in the control unit. ing.

  In the flowchart of FIG. 3, the steps up to (STEP 3) are the same as in the first embodiment. Next, the shell temperature of the compressor 1 is measured at the start of the refrigerant recovery operation (STEP 4). When the measurement is completed, the refrigerant recovery operation for recovering the refrigerant in the outdoor heat exchanger 3 is started (STEP 5). When the refrigerant in the indoor heat exchanger 5 decreases and the refrigerant is not sufficiently sucked into the compressor 1, the shell temperature of the compressor 1 rises, but the detected temperature of the thermistor 7 starts the refrigerant recovery operation. Sometimes, when the measured shell temperature becomes higher than a predetermined temperature set in the control unit, it is determined that the refrigerant has been sufficiently recovered, and the gas side on-off valve 6b is closed (STEP 7), and the compressor 1 is stopped and the refrigerant recovery operation ends (STEP 8). The predetermined temperature is set in advance in the predetermined temperature setting table based on the outside air temperature, and is selected at the start of the refrigerant recovery operation.

It is a refrigerant circuit diagram which shows the air conditioner by this invention. It is a flowchart explaining the operation | movement of the refrigerant | coolant collection | recovery driving | operation in a 1st Example. It is a flowchart explaining the operation | movement of the refrigerant | coolant collection | recovery driving | operation in a 2nd Example. It is the refrigerant circuit figure and block diagram which show the conventional air conditioner.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Expansion valve 5 Indoor heat exchanger 6a Liquid side on / off valve 6b Gas side on / off valve 7 Thermistor 8 Refrigerant leak sensor

Claims (2)

In an air conditioner comprising a refrigerant circuit by sequentially connecting a compressor, an outdoor heat exchanger, a decompression means, and an indoor heat exchanger,
In the refrigerant recovery operation in which the temperature detection means is provided in the shell of the compressor and the refrigerant is recovered from the indoor side to the outdoor side, when the temperature detected by the temperature detection means becomes higher than a predetermined temperature, An air conditioner characterized in that the compressor is stopped to end the refrigerant recovery operation. In an air conditioner comprising a refrigerant circuit by sequentially connecting a compressor, an outdoor heat exchanger, a decompression means, and an indoor heat exchanger,
Temperature detection means is provided in the shell of the compressor, the temperature of the shell is measured at the start of the refrigerant recovery operation for recovering the refrigerant from the indoor side to the outdoor side, and the temperature detected by the temperature detection means during the recovery operation However, the air conditioner is characterized in that when the temperature rises by a predetermined temperature or more from the temperature of the shell, the compressor is stopped and the refrigerant recovery operation is terminated.

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