JP2012007775A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem with a pump-down operation, wherein there is a possibility that hydrofluoroolefin may be decomposed due to a rise of a temperature of a sliding part during the pump-down operation since the hydrofluoroolefin is liable to be decomposed.SOLUTION: An outdoor machine 100 includes: a compressor 1; an outdoor heat exchanger 2; an outdoor blower 3; an expansion valve 4; a liquid-side connecting valve 5; and a gas-side connecting valve 8. An indoor machine 101 includes an indoor heat exchanger 6 and an indoor blower 7. HFO-1234yf is used as a coolant. A time of the pump-down operation is shortened by recovering the coolants from both liquid-side connecting piping 21 and gas-side connecting piping 22 by switching the liquid-side connecting valve 5, the rise of the temperature of the sliding part of the compressor 1 is suppressed, and the decomposition of the coolant is prevented, thus improving reliability.

Description

  The present invention relates to an air conditioner that uses a working refrigerant to form a refrigeration and heat pump cycle for air conditioning, and particularly in an apparatus that forms a cycle by connecting an indoor unit and an outdoor unit with a connecting pipe. When using a working refrigerant with multiple bonds, a technology that can quickly pump down to prevent decomposition of the refrigerant by suppressing a rise in the temperature of the compressor during pump down work to collect the working refrigerant in the outdoor unit. It is to provide.

  In the separation type air conditioner, the refrigerant is usually sealed in the outdoor unit, and after connecting the indoor unit and the outdoor unit with the connection pipe on the liquid side and the gas side, the working refrigerant is opened to the connection pipe and the indoor unit. To install. And in order to transfer the apparatus once installed, when removing an indoor unit, an outdoor unit, and connection piping, the pump down operation | work which collect | recovers refrigerant | coolants to an outdoor unit is performed.

  Conventional pump-down operation is performed by closing the liquid-side on-off valve provided in the outdoor unit and performing cooling operation. When a predetermined time has elapsed, the gas-side on-off valve provided in the outdoor unit is closed and the operation is stopped. (See Patent Document 1).

  At this time, the working refrigerant on the indoor unit side is sucked into the compressor from the gas-side connecting pipe, and finally the working refrigerant in the liquid-side connecting pipe is sucked into the compressor, and the pump-down ends.

  If the pump-down time from the closing of the liquid-side on / off valve to the stoppage of operation is short, the working refrigerant remains on the indoor unit side and is released into the atmosphere when the connection pipe is removed. On the other hand, if the pump down time is too long, the compressor is operated in a state where the working refrigerant does not flow, and the temperature inside the compressor, particularly the sliding portion, rises.

  On the other hand, in recent years, global warming has become a major problem, and the movement to use working refrigerants with low global warming potential has become prominent. Natural refrigerants, hydrofluoroolefins having a double bond between carbon and carbon, etc. The refrigerant is attracting attention.

  Hydrofluoroolefins are particularly attracting attention as alternative refrigerants for R134a, and studies on practical application to automotive air conditioners are being promoted. The warming potential (100 years) is 4 in the case of HFO1234yf, which is very small compared to 1,300 for R134a and 1730 for R410A used in air conditioners. This characteristic that the warming coefficient is small is attributed to the fact that there is a double bond between carbon and it is easy to decompose.

JP-A-5-157382

  When the pump-down operation of the conventional air conditioner is applied to an air conditioner using hydrofluoroolefin, the working refrigerant may be decomposed due to a temperature rise inside the compressor.

  In the conventional air conditioner, since the working refrigerant is difficult to decompose, the material having the lowest heat resistant temperature in the compressor is a motor insulating film, and the heat resistant temperature is generally about 120 ° C. On the mechanical sliding surface where the temperature is considered to rise the most, no problem occurred even when the temperature reached about 200 ° C.

  However, since hydrofluoroolefin is easy to decompose | disassemble, there exists a possibility of decomposition | disassembly by the temperature rise of a sliding part at the time of pump down operation.

  It is not desirable that the refrigerant, which is a working fluid, decompose itself, and the product at the time of decomposition may adversely affect the metal surface and organic material.

  Therefore, the present invention provides a highly reliable air conditioner by solving such problems and performing a reliable pump down while suppressing a temperature rise inside the compressor.

  In order to solve the above-described conventional problems, the air conditioner of the present invention uses a gas side connection pipe, a liquid side when performing a pump-down operation in an air conditioner using a refrigerant containing hydrofluoroolefin as a working refrigerant. The refrigerant is recovered from both connection pipes to the outdoor unit.

  Thereby, the liquid refrigerant existing in the liquid side connection pipe can be easily recovered, the pump-down can be finished quickly, and the temperature rise inside the compressor can be suppressed.

  The air conditioner of the present invention can provide a highly reliable device that avoids refrigerant decomposition due to temperature rise when the pump is down.

The block diagram of the air conditioner in Embodiment 1 of this invention The block diagram of the air conditioner in Embodiment 2 of this invention

  The first invention includes an outdoor unit having compression means for compressing a working refrigerant, an outdoor heat exchanger, an expansion valve, an outdoor fan, a liquid side connection valve, a gas side connection valve, an indoor heat exchanger, and an indoor fan. Is an air conditioner that constitutes a refrigeration cycle or a heat pump cycle using a refrigerant containing hydrofluoroolefin as a working refrigerant, and connected to the outdoor unit by a liquid side connection pipe and a gas side connection pipe When performing the pump-down operation for collecting the working refrigerant, the refrigerant is collected from both the liquid side connection pipe and the gas side connection pipe.

  Thereby, the liquid refrigerant existing in the liquid side connection pipe can be easily recovered, the pump-down can be finished quickly, and the temperature rise inside the compressor can be suppressed.

  Therefore, decomposition of the hydrofluoroolefin as a refrigerant can be prevented and a highly reliable device can be provided.

  A second invention includes a bypass circuit for connecting the gas side connection valve and the liquid side connection valve in the first invention, wherein the liquid side connection valve includes a pipe connected to the expansion valve and the liquid side connection pipe. This is a switching valve that communicates with one of the bypass circuits.In normal operation, the piping connected to the expansion valve communicates with the liquid side connection piping, and during pump-down operation, the piping connected to the expansion valve and the bypass circuit are connected. It communicates.

  Thereby, the structure which collect | recovers a refrigerant | coolant easily from both gas side connection piping and liquid side connection piping is realizable only by switching a liquid side connection valve.

  Accordingly, it is possible to provide a highly reliable apparatus that can quickly finish pumping down with a simple operation.

  A third invention is the three-way valve according to the second invention, wherein the liquid-side connection valve and the gas-side connection valve have an access valve that can be opened by pushing the core. A detachable bypass means for connecting the connection valve and the access valve of the gas side connection valve is mounted.

  Thereby, since the detachable bypass means is used as a tool only during the pump down operation, it is not necessary to equip the apparatus.

  Therefore, the apparatus can be provided at low cost.

  In a fourth aspect based on the third aspect, the detachable bypass means includes a joint portion that can push the core and a suction valve for discharging the internal air.

  Thereby, the internal air can be easily discharged when the detachable bypass means is attached.

  Therefore, mixing of air can be prevented and highly reliable pump down operation can be performed.

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

(Embodiment 1)
FIG. 1 shows a configuration diagram of an air conditioner according to a first embodiment of the present invention.

  As shown in FIG. 1, the air conditioner in 1st Embodiment connects the outdoor unit 100 and the indoor unit 101 with the liquid side connection piping 21 and the gas side connection piping 22 which are connection piping, and is apparatus. It is composed.

  The outdoor unit 100 includes a compressor 1 that is a compression means, an outdoor heat exchanger 2, an outdoor blower 3, an expansion valve 4 that decompresses and expands working refrigerant, a liquid side connection valve 5 that is a three-way valve, and a gas side connection valve 8. Is provided. The liquid side connection valve 5 switches the connection of the liquid side connection pipe 21 to the expansion valve 4 or the bypass circuit 11. The bypass circuit 11 is connected from the liquid side connection valve 5 to the connection port on the gas side connection pipe 22 side of the gas side connection valve 8.

  The indoor unit 101 includes an indoor heat exchanger 6 and an indoor blower 7. The compressor 1, the outdoor heat exchanger 2, the expansion valve 4, the liquid side connection valve 5, the liquid side connection pipe 21, the indoor heat exchanger 6, the gas side connection pipe 22, and the gas side connection valve 8 are connected by piping. And constitutes a refrigerant circuit through which the working refrigerant flows. As the working refrigerant, HFO-1234yf, which is a hydrofluoroolefin having a double bond between carbons and having a small warming potential, is used.

  The air conditioner also includes a work instruction lamp 9 which is an output means for displaying that one process of pumping down is completed, and a work which is an input means for inputting that a worker has completed one process. A completion button 10 is provided. The work instruction lamp 9 and the work completion button 10 are provided on, for example, an outdoor unit control board constituting a control device of the air conditioner or a remote controller that communicates with the control device.

  The normal operation of the air conditioner configured as described above will be described. The working refrigerant that has returned from the indoor unit 101 to the outdoor unit 100 is sucked into the compressor 1 through the gas side connection valve 8 and compressed, and is sent to the outdoor heat exchanger 2 as a high-temperature and high-pressure refrigerant. 3 is cooled and condensed by the air sent by 3, decompressed by the expansion valve 4, sent to the indoor unit 101 through the liquid side connection valve 5, and from the air sent by the indoor blower 7 in the indoor heat exchanger 6. It takes heat and evaporates and returns to the outdoor unit 100. By taking heat from the air sent by the indoor blower 7 in the indoor heat exchanger 6, the air in the space where the indoor unit 101 is installed is cooled, that is, cooled.

  Next, the time of installation and relocation of such an air conditioner will be described.

  In the separation type air conditioner shown in FIG. 1, the refrigerant is sealed in the outdoor unit 100 before installation. At the time of installation, the indoor unit 101 and the outdoor unit 100 are connected by the liquid side connection pipe 21 and the gas side connection pipe 22. Thereafter, the service port 12 of the gas side connection valve 8 and the vacuum pump are connected by a hose. Then, by operating the vacuum pump, the air in the pipe on the indoor unit 101 side (the pipe from the liquid side connection valve 5 to the gas side connection valve 8 and including the indoor heat exchanger 6) is exchanged with the gas side connection valve 8. The service port 12 is evacuated. Thereafter, the liquid side connection valve 5 and the gas side connection valve 8 are opened to open the refrigerant in the pipe for installation. At this time, the bypass circuit 11 is connected to the indoor unit 101 side and, like the piping on the indoor unit 101 side, is evacuated and then filled with the refrigerant.

  Further, when the installed air conditioner is moved, the working refrigerant is again collected in the outdoor unit 100 and moved by removing the liquid side connection pipe 21 and the gas side connection pipe 22. Such an operation of collecting the working refrigerant again in the outdoor unit 100 is referred to as pump down.

  In the case of a conventional air conditioner, the pump down is performed for a predetermined time as a preliminary operation, and then the two-way valve provided in place of the liquid side connection valve 5 is closed and the cooling operation is performed for about 3 minutes. Subsequently, the three-way valve provided in place of the gas side connection valve 8 is closed, and the operation is stopped. At this time, when the pressure measurement means such as a gauge manifold is connected to the service port of the three-way valve provided in place of the gas side connection valve 8 and pumping down is performed, until the pressure measurement means displays negative pressure, Cooling operation is performed with the two-way valve provided instead of the liquid side connection valve 5 closed.

  At this time, if the pump down is not sufficient, the working refrigerant remains in the connection pipe and the pipe on the indoor unit 101 side. As a result, if the connection pipe is removed as it is, the working refrigerant is released into the atmosphere. Although the global warming potential is small, it is not desirable that the fluorine compound is released into the atmosphere, and it is desirable to collect the working refrigerant as much as possible from the viewpoint of reducing the working refrigerant in the apparatus. However, if the pump-down operation is continued for a long time, the operation in a state where the working refrigerant does not circulate continues, so that cooling of the sliding portion of the compressor 1 is hindered, and the temperature of the sliding portion of the compressor 1 rises.

  Here, in the air conditioner of the present embodiment, HFO-1234yf is used as a working refrigerant. However, since this refrigerant has a double bond between carbons, it is easily decomposed and oxygen is present. If the temperature rises, it will easily decompose and produce acid and various organic substances, metal parts such as the sliding parts and piping of the compressor 1, motor windings of the compressor 1, etc. There is a possibility of damaging the organic material in each valve part.

  Further, even when oxygen is not present, the refrigerant is decomposed at the high temperature portion. The material having the lowest heat resistant temperature in the compressor 1 is an insulating film of a motor, and the heat resistant temperature is generally about 120 ° C. The mechanical sliding surface that is considered to have the highest temperature reaches a temperature of about 200 ° C. Conventionally, since the refrigerant was difficult to decompose, no problem occurred. However, in the apparatus using HFO-1234yf as the refrigerant, it is easy to decompose, and therefore the working refrigerant is increased due to the temperature rise of the sliding portion during the pump down operation. May break down.

  Therefore, the air conditioner of Embodiment 1 of the present invention shortens the time of the pump-down operation as follows, suppresses the temperature rise of the sliding portion of the compressor 1, and prevents the working refrigerant from being decomposed and is reliable. It is intended to improve the performance.

  First, the basic idea is to collect the refrigerant from both the liquid side connection pipe 21 and the gas side connection pipe 22 to the outdoor unit 100 during the pump down operation.

  The reason for this will be described below. Since the liquid side connection pipe 21 is covered with a heat insulating material, the liquid refrigerant inside the liquid side connection pipe 21 is not easily evaporated by heat absorption. For this reason, the working refrigerant present inside the liquid side connection pipe 21 is in a state where the dryness is the lowest on the low pressure side. On the other hand, in the indoor heat exchanger 6, even if there is a liquid refrigerant, heat is exchanged with the air and it is quickly evaporated. Further, since the gas side connection pipe 22 is also covered with the heat insulating material, it is not possible to expect rapid evaporation of the working refrigerant, but since it is carried to the compressor 1 together with the working refrigerant evaporated in the indoor heat exchanger 6, Is recovered by the compressor 1.

  The liquid refrigerant is likely to stay during the pump-down operation, and when the liquid pool is generated, the refrigerant in that portion is evaporated and then collected by the compressor 1, so it is necessary to absorb heat from the surroundings. When a part of the liquid refrigerant evaporates with the heat of evaporation from the surroundings, the ambient temperature decreases accordingly. As the evaporation and temperature decrease are repeated, the ambient temperature of the liquid refrigerant decreases, and the liquid refrigerant becomes more difficult to evaporate and it takes time to recover the refrigerant.

  On the other hand, when the amount of liquid refrigerant is small, the ambient temperature is kept at a relatively high temperature, and the liquid refrigerant is kept in a state where it is easily evaporated. As a result, the working refrigerant can be quickly recovered, the temperature rise of the sliding portion of the compressor 1 can be suppressed, and the refrigerant can be prevented from being decomposed to improve the reliability.

  A method of recovering the refrigerant from both the liquid side connection pipe 21 and the gas side connection pipe 22 to the outdoor unit 100 is as follows. In the pump down, after performing a cooling operation for a predetermined time as a preliminary operation, the liquid side connection valve 5 is switched so that the liquid side connection pipe 21 and the bypass circuit 11 communicate with each other. As a result, the pipe connected to the expansion valve 4 does not communicate with the suction side of the compressor 1. Then, the cooling operation is continued for about 3 minutes, and the refrigerant in the liquid side connection pipe 21 is recovered to the compressor 1 directly through the bypass circuit 11 and the refrigerant in the gas side connection pipe 22 is directly recovered. Thereafter, the gas side connection valve 8 is closed and the operation is stopped. At this time, when pressure measurement means such as a gauge manifold is connected to the service port 12 of the gas side connection valve 8 and pumping down is performed, the liquid side connection valve 5 is kept until the pressure measurement means displays negative pressure. The cooling operation is performed in a state where the side connection pipe 21 and the bypass circuit 11 are switched so as to communicate with each other.

  When the refrigerant is recovered from both the liquid side connection pipe 21 and the gas side connection pipe 22 as in the present embodiment, the indoor heat exchanger 6 becomes a place where a liquid pool is generated. However, as described above, in the indoor heat exchanger 6, even if there is a liquid refrigerant, it exchanges heat with air and evaporates, together with the refrigerant in the liquid side connection pipe 21 and the gas side connection pipe 22 regardless of the liquid or gas state. , Promptly collected in the outdoor unit 100.

  In the present embodiment, since the liquid side connection valve 5 is configured to switch the connection of the liquid side connection pipe 21 to the expansion valve 4 or the bypass circuit 11, only by operating the liquid side connection valve 5, Since the tip of the expansion valve 4 is sealed and the liquid side connection pipe 21 is connected to the gas side connection valve 8 by the bypass circuit 11, both the liquid side connection pipe 21 and the gas side connection pipe 22 can be easily operated. The refrigerant can be collected in the outdoor unit 100. That is, the air conditioner of the present embodiment can avoid the decomposition of the working refrigerant due to the temperature rise at the time of pump down.

  In this embodiment, the work instruction lamp 9 which is an output means for notifying that the work procedure is ready to proceed and the work completion which is an input means for inputting that the worker has completed one work. A button 10 is provided. When the worker is ready to proceed with the work, the work instruction lamp 9 is turned on or blinking to notify the user. When the worker finishes one work, the work completion button 10 is used to complete the work. By inputting, it is possible to reliably perform each work and reduce the occurrence of work errors.

  For example, when pumping down is performed, the worker first presses the work completion button 10 and inputs the start of the work. Then, a control device (not shown) starts the cooling operation of the air conditioner. Then, when the cooling operation is performed for a certain time, the work instruction lamp 9 blinks once. The worker who confirmed this operates the liquid side connection valve 5 and presses the work completion button 10 to start the pump down operation. Then, when the predetermined time has passed, the air conditioner repeats blinking of the work instruction lamp 9 twice to inform the end of the pump down operation process. When the worker who has confirmed this closes the gas side connection valve 8 and presses the work completion button 10, the air conditioner stops operation. This completes the pump down.

  That is, the air conditioner according to the present embodiment can reliably perform each process by the work instruction lamp 9 and the work completion button 10 and reduce work mistakes.

  In the present embodiment, the operation of the liquid side connection valve 5 and the gas side connection valve 8 is performed by an operator, and the completion of these operations is input by pressing the work completion button 10. The operation of the side connection valve 5 and the gas side connection valve 8 is also automatically performed by the control device, so that the work completion button 10 can be eliminated. In this case, it goes without saying that work errors can be further reduced.

(Embodiment 2)
FIG. 2 shows a configuration diagram of an air conditioner according to the second embodiment of the present invention.

  As shown in FIG. 2, in the air conditioner of FIG. 1, the liquid side connection valve 5 is changed to a liquid side connection three-way valve 15 provided with a service port 12, and the bypass circuit 11 and the core of the service port 12 are optional. It is changed to a detachable bypass circuit 31 having a joint valve 33 that can be pushed in at a timing, a suction valve 32 having an opening / closing valve and a connection port to a vacuum pump. The detachable bypass circuit 31 is connected to the liquid side connection three-way valve 15 and the service port 12 of the gas side connection valve 8 only when the pump is down.

  In the present embodiment, the detachable bypass circuit 31 is attached only when the pump is down. Therefore, during normal operation, the outdoor unit 100 of the air conditioner is not equipped with the detachable bypass circuit 31, and the apparatus is inexpensive. Can be provided.

  Further, when the detachable bypass circuit 31 is attached, if the air is exhausted from the suction valve 32 and then pumped down, the air can be prevented from being mixed into the refrigerant and a highly reliable operation can be performed. .

  In addition, although the air conditioner in the above embodiment is a cooling only machine which cannot perform heating operation, it can equip with the four-way valve which switches the flow direction of a working refrigerant at the exit of the compressor 1, and can perform heating operation. The same effect can be obtained even in cool and warm models.

  Moreover, although HFO-1234yf was used as the refrigerant, even if it is HFO-1234ze or a mixed refrigerant containing HFO-1234yf or HFO-1234ze, the same effect can be obtained. An example of such a mixed refrigerant is a mixed refrigerant of HFO-1234yf and HFC-32.

  As described above, when performing the pump-down operation, the air conditioner according to the present invention recovers the refrigerant from both the liquid-side connection pipe and the gas-side connection pipe and performs the pump-down operation. As a result, the pump-down can be quickly finished, and the temperature rise inside the compressor can be suppressed.

  As a result, a refrigerant that is easily decomposed, such as a hydrofluoroolefin having a double bond between carbon and carbon, can be used, and the environment is excellent.

  Further, the present invention is not limited to the air conditioner, and can be widely applied to a separate type showcase, a refrigerator, a heat pump type water heater, and the like, and brings about an effect.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Outdoor heat exchanger 3 Outdoor blower 4 Expansion valve 5 Liquid side connection valve 6 Indoor heat exchanger 7 Indoor blower 8 Gas side connection valve 9 Work instruction lamp 10 Work completion button 11 Bypass circuit 12 Service port 21 Liquid side connection Piping 22 Gas side connection piping 100 Outdoor unit 101 Indoor unit

Claims (4)

Compressing means for compressing working refrigerant, outdoor heat exchanger, expansion valve, outdoor fan, liquid side connection valve, outdoor unit having gas side connection valve, indoor heat exchanger, indoor unit having indoor fan, liquid side An air conditioner constituting a refrigeration cycle or a heat pump cycle using a refrigerant containing hydrofluoroolefin as the working refrigerant, connected by a connection pipe and a gas side connection pipe, wherein the working refrigerant is supplied to the outdoor unit An air conditioner that collects refrigerant from both the liquid-side connection pipe and the gas-side connection pipe when performing a pump-down operation for recovery. A bypass circuit for connecting the gas side connection valve and the liquid side connection valve, wherein the liquid side connection valve is either one of the pipe connected to the expansion valve and the bypass circuit. A switching valve that communicates with the expansion valve during normal operation, and communicates the pipe connected to the liquid side connection piping with the bypass circuit during the pump-down operation. The air conditioner according to claim 1, wherein The liquid side connection valve and the gas side connection valve are three-way valves having an access valve that can be opened by pushing in a core, and the liquid side connection valve and the gas side connection valve during the pump down operation The air conditioner according to claim 1, further comprising a detachable bypass means for connecting the access valve. The air conditioner according to claim 3, wherein the detachable bypass means includes a joint portion through which the core can be pushed in, and a suction valve for discharging the internal air.

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