JP2009210174A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a wasteful flow of a refrigerant caused in an antifreezing pipe in defrosting operation, and to surely achieve an antifreezing object by making the best use of heat of a high-temperature refrigerant staying in the antifreezing pipe in heating operation. <P>SOLUTION: A heat pump cycle 1 includes a compressor 2, an outdoor heat exchanger 4, a pressure reduced expansion device 5 and an indoor heat exchanger 6. An antifreezing pipe 7 for transferring the heat of the refrigerant in the heat pump cycle 1 to drain water is installed in a drain pan placed under the outdoor heat exchanger 4. The antifreezing pipe 7 is put in a connected state as a bypass passage at a portion where the refrigerant flows from the indoor heat exchanger 6 to the outdoor heat exchanger 4 during heating in the heat pump cycle 1. The antifreezing pipe 7 is provided with an opening and closing device 8 for cutting off the entering and leaving of the refrigerant in a space up to the heat pump cycle 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air conditioner that performs heating using a heat pump cycle.

  In the case of an air conditioner that performs heating using a heat pump cycle, during the heating operation, the outdoor heat exchanger becomes an evaporator, the surface temperature decreases, and moisture in the outdoor air is condensed on the fins. When the outside air temperature is low (especially in a cold region), condensed water freezes or moisture adheres (frosts) in the form of frost. Since heat exchange is hindered when ice or frost covers the surface of the fin, the defrosting operation is performed at an appropriate timing.

  In the defrosting operation, the outdoor heat exchanger is temporarily used as a condenser, and a high-temperature refrigerant is flowed to melt ice and frost attached to the fins. Drain water in which ice or frost has melted is received and drained by the drain pan, but may freeze in the drain pan before being drained, such as when the outside air temperature is particularly low. When the ice layer closes the drain outlet and drainage stops, the drain water level in the drain pan rises and the ice layer rises. As the situation further progresses, ice may come into contact with the outdoor heat exchangers and fans, causing them to break.

  In order to cope with the above problem, a mechanism for taking out heat from a heat pump cycle and preventing freezing has been proposed. Examples thereof can be seen in Patent Documents 1 and 2.

  The circuit configuration of the air conditioner described in Patent Literature 1 is shown in FIG. In this air conditioner, a compressor 101, an indoor heat exchanger 102, a decompression / expansion means 103, and an outdoor heat exchanger 104 constitute a heat pump cycle. A check valve 105 is provided between the indoor heat exchanger 102 and the decompression and expansion means 103, and a two-way valve 106 and an antifreeze pipe 107 are provided so as to bypass the front and rear of the check valve 105.

  In FIG. 10, a solid line arrow indicates the refrigerant flow direction during the cooling operation, and a broken line arrow indicates the refrigerant flow direction during the heating operation. During the cooling operation, the refrigerant discharged from the compressor 101 condenses in the outdoor heat exchanger 104, enters the indoor heat exchanger 102 from the decompression / expansion means 103 through the check valve 105, and evaporates there to heat from the indoor air. After taking in, it returns to the compressor 101. At this time, the two-way valve 106 is closed, and the refrigerant does not flow through the freeze prevention pipe 107. During the heating operation, the refrigerant discharged from the compressor 101 condenses in the indoor heat exchanger 102, does not flow to the check valve 105, and passes through the anti-freezing pipe 107, the two-way valve 106, and further the decompression expansion means 103, and the outdoor heat. After entering the exchanger 104, it evaporates and takes heat from the outdoor air, and then returns to the compressor 101. The condensation heat of the refrigerant flowing through the antifreezing pipe 107 prevents the water tray from freezing.

  In the air conditioner described in Patent Literature 2, an outer expansion valve and an inner expansion valve are connected in series in the middle of a circuit for flowing refrigerant from the outdoor heat exchanger to the indoor heat exchanger during cooling operation. The circuit portion between the inner expansion valves is a bottom plate heater. And the bypass pipe which bypasses a baseplate heater is provided, and the adjustment valve is arrange | positioned there.

  During heating operation, the high-temperature and high-pressure refrigerant discharged from the compressor radiates and condenses in the indoor heat exchanger, then passes through the inner expansion valve, and then the bottom plate heater at a predetermined flow rate ratio depending on the possibility of freezing. And through the regulating valve and bypass pipe to the outer expansion valve. And it takes in heat from outdoor air with an outdoor heat exchanger, and returns to a compressor.

During the de-ice operation, the refrigerant flow reverses, and the high-temperature and high-pressure refrigerant discharged from the compressor dissipates heat in the outdoor heat exchanger to perform defrosting. The regulating valve is closed and the refrigerant flows into the bottom plate heater to prevent the drainage from freezing.
Shokai 62-102924 JP2005-49002

  In the air conditioner described in Patent Document 1, the anti-freezing pipe is used, and in the air conditioner described in Patent Document 2, the anti-freezing is performed by flowing a high-temperature and high-pressure refrigerant through the bottom plate heater. If the pressure on the indoor heat exchanger side becomes low during the defrosting operation, the high-temperature and high-pressure refrigerant stored in the antifreezing pipe or the bottom plate heater is drawn out to the indoor heat exchanger side. For this reason, the temperature of the antifreezing pipe or the bottom plate heater is lowered, and the defrosted warm drain water may be cooled to cause freezing. In addition, if all the high-temperature and high-pressure refrigerant that has exited the indoor heat exchanger during the heating operation is passed through the antifreeze pipe or the bottom plate heater, the heating capacity is reduced.

  The present invention has been made in view of the above points, and prevents the flow of useless refrigerant from occurring in the anti-freezing pipe during the defrosting operation, and the heat of the high-temperature refrigerant stored in the anti-freezing pipe during the heating operation. The purpose is to ensure that the purpose of freezing prevention is achieved.

  To achieve the above object, the present invention constitutes a heat pump cycle including a compressor, an outdoor heat exchanger, a decompression expansion device, and an indoor heat exchanger, and a drain pan placed under the outdoor heat exchanger, In the air conditioner having an anti-freezing pipe that transmits the heat of the refrigerant in the heat pump cycle to the drain water, the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger during the heating operation in the heat pump cycle. The anti-freezing pipe is connected to the location as a bypass path, and the anti-freezing pipe is provided with an opening / closing device capable of blocking the refrigerant in and out of the heat pump cycle.

  According to this configuration, at the time of heating operation, the open / close device can be opened to flow the high-temperature and high-pressure refrigerant through the anti-freezing pipe, thereby preventing the drain water from freezing. During the defrosting operation, the switchgear can be closed to prevent the high-temperature refrigerant accumulated in the antifreezing pipe from being drawn out to the indoor heat exchanger side and the temperature of the antifreezing pipe from being lowered.

  In addition, since the anti-freezing pipe is a bypass, it is not always necessary to pass the entire amount of the refrigerant through the anti-freezing pipe during heating operation, and a decrease in heating capacity can be suppressed.

  In the air conditioner having the above-described configuration, the opening / closing device includes an electromagnetic on-off valve provided near a connection portion of the heat pump cycle and the freeze prevention pipe on the indoor heat exchanger side, the heat pump cycle, and the freeze prevention pipe. And a check valve that allows only the refrigerant flow in the direction of exiting from the antifreezing pipe.

  According to this configuration, it is possible to easily configure an opening / closing device that can block the refrigerant from entering and exiting the freeze prevention pipe.

  In the air conditioner having the above-described configuration, the opening / closing device includes an electromagnetic on-off valve provided near a connection portion of the heat pump cycle and the freeze prevention pipe on the indoor heat exchanger side, the heat pump cycle, and the freeze prevention pipe. It is preferable that it is comprised by the electromagnetic on-off valve provided near the connection location by the side of the said outdoor heat exchanger.

  According to this configuration, both of the electromagnetic on-off valves can be closed, and the high-temperature and high-pressure refrigerant accumulated during the heating operation can be confined in the anti-freezing pipe and then the defrosting operation can be performed. Since the refrigerant amount to be confined is large, the antifreezing pipe holds a larger amount of heat, and the antifreezing can be further ensured.

  In the air conditioner having the above configuration, it is preferable that the electromagnetic on-off valve is open for at least a predetermined period during heating operation, and the electromagnetic on-off valve is closed at the start of defrosting operation.

  According to this configuration, the high-temperature and high-pressure refrigerant can be taken into the anti-freezing pipe during the heating operation, and the taken-in high-temperature and high-pressure refrigerant can be held in the anti-freezing pipe as it is when the defrosting operation is started.

  In the air conditioner having the above-described configuration, it is preferable that the control unit of the air conditioner performs operation control for increasing the refrigerant condensing temperature when moving from the heating operation to the defrosting operation.

  According to this configuration, it is possible to delay the temperature decrease of the anti-freezing pipe during the defrosting operation.

  According to the present invention, in the air conditioner having the above-described configuration, it is preferable that a protrusion that is immersed in the drain water in the drain pan is formed on the freeze prevention pipe.

  According to this configuration, the heat of the freeze prevention pipe can be efficiently transmitted to the drain water.

  According to the present invention, it is possible to prevent the drain water from freezing during the defrosting operation by utilizing the heat of the high-temperature refrigerant stored in the antifreezing pipe during the heating operation, and it is possible to efficiently use the heat energy. In this way, by efficiently using thermal energy to prevent drain water from freezing, a drain water drainage route is always secured, and it is possible to carry out heating operation continuously for a long time in a cold region. A high air conditioner can be obtained.

  A first embodiment of the present invention is shown in FIGS. 1 and 2 are refrigeration cycle diagrams of the air conditioner, FIG. 1 shows a state during a heating operation, and FIG. 2 shows a state during a defrosting operation. 3 to 5 are perspective views of some components.

  The air conditioner according to the present invention uses a heat pump cycle 1 shown in FIG. 1 as a refrigeration cycle. The heat pump cycle 1 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, a decompression expansion device 5, and an indoor heat exchanger 6 connected in a loop.

  In the heat pump cycle 1, at the time of heating operation, the freeze prevention pipe 7 is connected at two places as a bypass path to the place where the refrigerant flows from the indoor heat exchanger 6 side to the outdoor heat exchanger 4 side. That is, one connection location is set near the indoor heat exchanger 6 and the other connection location is set near the outdoor heat exchanger 4. Any connection location is upstream of the decompression and expansion device 5.

  The antifreezing pipe 7 is provided with an opening / closing device 8 that can block the refrigerant from entering and exiting the heat pump cycle 1. The opening / closing device 8 includes an electromagnetic opening / closing valve 9 provided near the connection location on the indoor heat exchanger 6 side and a check valve 10 provided near the connection location on the outdoor heat exchanger 4 side. The check valve 10 allows the refrigerant to flow from the antifreeze pipe 7 to the heat pump cycle 1, but does not allow the refrigerant to flow from the heat pump cycle 1 to the antifreeze pipe 7. The electromagnetic on-off valve 9 may be one that can perform only opening / closing control, or may be capable of adjusting the opening degree in addition to the opening / closing control.

  3 to 5, a drain pan for receiving drain water that is placed under the outdoor heat exchanger 4 and droops from the outdoor heat exchanger 4 in addition to the L-shaped outdoor heat exchanger 4 and the antifreezing pipe 7. 11 is shown. The antifreezing pipe 7 is placed between the outdoor heat exchanger 4 and the drain pan 11, and is bent so as to match the planar shape of the outdoor heat exchanger 4. A plurality of drain discharge ports 12 are formed in the drain pan 11 along the antifreezing pipe 7. When assembling the outdoor unit, first, as shown in FIG. 4, the freeze prevention pipe 7 is fixed at a position of the drain pan 11 soaked in drain water (not shown), and then, as shown in FIG. The outdoor heat exchanger 4 is fixed.

  The operation of the air conditioner of the first embodiment is as follows. FIG. 1 shows a state during heating operation. At this time, the high-temperature and high-pressure refrigerant discharged from the compressor 2 enters the indoor heat exchanger 6 where it dissipates heat and condenses. The refrigerant leaving the indoor heat exchanger 6 is still kept at a high temperature, and a part of the refrigerant flows into the antifreezing pipe 7 because the electromagnetic on-off valve 9 is open. The electromagnetic on-off valve 9 is assumed to be open for at least a predetermined period during heating operation. The heat of the refrigerant flowing through the antifreezing pipe 7 is transmitted to the drain water in the drain pan 11, and the drain water is prevented from freezing. The refrigerant that has passed through the antifreezing pipe 7 returns to the heat pump cycle 1 through the check valve 10, enters the outdoor heat exchanger 4 from the decompression expansion device 5, expands there, takes heat from the outdoor air, and then compresses the compressor. Return to 2.

  FIG. 2 shows a state during cooling operation or defrosting operation. At this time, the refrigerant flow is reversed from that during the heating operation. That is, the high-temperature and high-pressure refrigerant discharged from the compressor 2 enters the outdoor heat exchanger 4 where it dissipates heat and condenses. The refrigerant exiting the outdoor heat exchanger 4 enters the indoor heat exchanger 6 from the decompression / expansion device 5 and expands there, takes heat from the indoor air, and returns to the compressor 2. Due to the presence of the check valve 10, the refrigerant does not flow into the antifreezing pipe 7 from the connection location on the outdoor heat exchanger 4 side. In addition, the electromagnetic on-off valve 9 is closed at this time, and the refrigerant does not flow into the antifreezing pipe 7 from the connection portion on the indoor heat exchanger 6 side.

  When the internal pressure of the freeze prevention pipe 7 is high, the refrigerant may flow out to the heat pump cycle 1 through the check valve 10. However, if the pressures of the heat pump cycle 1 and the freeze prevention pipe 7 are balanced, the refrigerant stops flowing out at that time, and the refrigerant between the electromagnetic on-off valve 9 and the check valve 10 stays in the freeze prevention pipe 7. .

  The defrosting operation is performed during the heating operation. When the opening / closing device 8 is closed at that time, a high-temperature refrigerant is trapped in the antifreezing pipe 7. Since this refrigerant is not drawn to the indoor heat exchanger 6 side, the temperature is kept relatively long and the drain water is prevented from freezing. In addition, as a timing which closes the electromagnetic on-off valve 9 of the opening / closing device 8, it is preferable to select a time when the compressor 2 is operating for a heating operation that is a predetermined time before the start of the defrosting operation. In this way, the high-temperature refrigerant can be more reliably confined in the freeze prevention pipe 7.

  For example, for defrosting, the compressor 2 is temporarily stopped during the heating operation (heating operation is interrupted), the four-way valve 3 is switched, and then the compressor 2 is restarted to reverse the refrigerant flow. In this case, the electromagnetic on-off valve 9 may be closed a predetermined time (for example, “1 minute” or “3 minutes”) before the compressor is stopped. For the “predetermined time”, an appropriate experiment may be performed to set an appropriate time.

  Since the anti-freezing pipe 7 is a bypass, it is not always necessary to pass the entire amount of the refrigerant through the anti-freezing pipe 7 during the heating operation, and a decrease in heating capacity can be suppressed.

  A control unit (not shown) of the air conditioner performs operation control for increasing the refrigerant condensing temperature when moving from the heating operation to the defrosting operation. Specifically, control is performed such as stopping a fan (not shown) of the indoor heat exchanger 6, increasing the number of rotations of the compressor 2, and restricting the decompression / expansion device 5. Thereby, the temperature of the refrigerant | coolant which flows in into the antifreezing pipe 7 can be raised, and the temperature fall of the antifreezing pipe 7 during a defrost operation can be delayed.

  A second embodiment of the present invention is shown in FIGS. 6 and 7 are refrigeration cycle diagrams of the air conditioner, FIG. 6 shows a state during the heating operation, and FIG. 7 shows a state during the defrosting operation.

  The second embodiment differs from the first embodiment in that an electromagnetic on-off valve 13 is arranged instead of the check valve 10. That is, both ends of the freeze prevention pipe 7 are opened and closed by the electromagnetic on-off valves. The electromagnetic on-off valve 13 will be described as a type that can perform only on-off control, similarly to the electromagnetic on-off valve 9.

  The electromagnetic on-off valves 9 and 13 are assumed to be open for at least a predetermined period during the heating operation. When moving from the heating operation to the defrosting operation, the compressor 2 is stopped after the electromagnetic on-off valves 9 and 13 are closed. As a result, the high-temperature and high-pressure refrigerant can be confined in the anti-freezing pipe 7. Thereafter, the four-way valve 3 is switched to form a defrost cycle, and the compressor 2 is driven to perform a defrost operation.

  After the defrosting is completed, the compressor 2 is stopped and the four-way valve 3 is switched to form a heating cycle. Next, the electromagnetic on-off valves 9 and 13 are opened to allow the refrigerant to freely enter and exit from the freeze prevention pipe 7 and then the drive of the compressor 2 is resumed.

  According to the structure of 2nd Embodiment, even if the internal pressure of the freeze prevention pipe 7 is high at the time of a defrost operation, a refrigerant | coolant does not flow into the heat pump cycle 1 like 1st Embodiment. Therefore, the amount of refrigerant confined in the antifreeze pipe 7 is large, and the antifreeze pipe 7 retains a larger amount of heat. For this reason, freeze prevention can be made more reliable.

  The timing for closing the electromagnetic on-off valves 9 and 13 of the opening / closing device 8 is preferably selected when the compressor 2 is operating for heating operation, which is a predetermined time before the start of the defrosting operation. In this way, the high-temperature refrigerant can be more reliably confined in the freeze prevention pipe 7.

  For example, for defrosting, the compressor 2 is temporarily stopped during the heating operation (heating operation is interrupted), the four-way valve 3 is switched, and then the compressor 2 is restarted to reverse the refrigerant flow. In this case, the electromagnetic on-off valves 9 and 13 may be closed a predetermined time (for example, “1 minute” or “3 minutes”) before the compressor stops. For the “predetermined time”, an appropriate experiment may be performed to set an appropriate time. In closing the electromagnetic on-off valves 9 and 13, both may be closed at the same time, but either one may be closed first, and the other may be closed with a little delay.

  In the second embodiment, as in the first embodiment, the operation control for increasing the refrigerant condensing temperature can be performed when the heating operation is shifted to the defrosting operation.

  A third embodiment of the present invention is shown in FIGS. FIG. 8 is a perspective view of some components, and FIG. 9 is a partially enlarged cross-sectional view of the freeze prevention pipe.

  The third embodiment relates to the structure of the anti-freezing pipe 7 and can be duplicated in both the first embodiment and the second embodiment. In the third embodiment, the protrusions 14 that are immersed in the drain water in the drain pan 11 are provided in the freeze prevention pipe 7. Providing the protrusion 14 can be realized by fixing another member having a protrusion shape to the antifreezing pipe 7 by fitting or brazing. It is preferable that the protrusion 14 protrudes downward from the antifreeze pipe 7 and penetrates the drain outlet 12. Moreover, as shown in FIG. 9, it is preferable that the protrusion 14 is hollow and has a structure in which a refrigerant enters.

  By providing the projections 14 as described above, the heat of the freeze prevention pipe 7 can be efficiently transmitted to the drain water. Further, if the projection 14 passes through the drain drain port 12 or does not penetrate through the drain drain port 12, the drain water is guided to the projection 14 and smoothly drained from the drain drain port 12. Thereby, the drain water retention amount in the drain pan 11 decreases, and as a result, the risk of icing can be reduced. Moreover, since the protrusion 14 conducts heat intensively around the drain outlet 12, the situation where the drain outlet 12 is closed with ice can be avoided.

  Each embodiment of the present invention has been described above, but various modifications can be made without departing from the spirit of the present invention.

  The present invention is widely applicable to an air conditioner that performs heating using a heat pump cycle.

It is a refrigeration cycle diagram of the air conditioner according to the first embodiment, and shows a state during heating operation. It is a refrigerating cycle figure of the air conditioner concerning a 1st embodiment, and shows the state at the time of defrosting operation. The perspective view of the one part component of the air conditioner which concerns on 1st Embodiment. The same perspective view as in FIG. 3, with the combination of components advanced The same perspective view as in FIG. 4, with the combination of components further advanced The refrigeration cycle diagram of the air conditioner according to the second embodiment, showing the state during heating operation It is a refrigeration cycle diagram of the air conditioner according to the second embodiment, and shows the state during the defrosting operation. The perspective view of the one part component of the air conditioner which concerns on 3rd Embodiment. The partial expanded sectional view of the freeze prevention pipe of the air conditioner concerning a 3rd embodiment Refrigeration cycle diagram of a conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat pump cycle 2 Compressor 3 Four-way valve 4 Outdoor heat exchanger 5 Decompression expansion device 6 Indoor heat exchanger 7 Freezing prevention pipe 8 Opening and closing device 9 Electromagnetic on-off valve 10 Check valve 11 Drain pan 12 Drain drain port 13 Electromagnetic on-off valve 14 Protrusion

Claims (6)

A heat pump cycle including a compressor, an outdoor heat exchanger, a decompression and expansion device, and an indoor heat exchanger is configured, and the heat of the refrigerant in the heat pump cycle is drained to a drain pan placed under the outdoor heat exchanger. In an air conditioner that installs anti-freezing pipes that communicate with
In the heat pump cycle, the antifreeze pipe is connected as a bypass path to a location where the refrigerant flows from the indoor heat exchanger to the outdoor heat exchanger during heating operation, and the antifreeze pipe is connected to the heat pump. An air conditioner characterized in that an open / close device capable of interrupting refrigerant in and out of the cycle is provided.   The open / close device is an electromagnetic on-off valve provided near the connection point on the indoor heat exchanger side of the heat pump cycle and the freeze prevention pipe, and the outdoor heat exchanger side of the heat pump cycle and the freeze prevention pipe 2. The air conditioner according to claim 1, wherein the air conditioner is configured by a check valve that is provided in the vicinity of the connection point and permits only the refrigerant flow in the direction of exiting from the antifreezing pipe.   The open / close device is an electromagnetic on-off valve provided near the connection point on the indoor heat exchanger side of the heat pump cycle and the freeze prevention pipe, and the outdoor heat exchanger side of the heat pump cycle and the freeze prevention pipe The air conditioner according to claim 1, wherein the air conditioner is configured by an electromagnetic on-off valve provided near the connection point.   The air conditioner according to claim 2 or 3, wherein the electromagnetic on-off valve is open at least for a predetermined period during heating operation, and the electromagnetic on-off valve is closed at the start of defrosting operation.   The air conditioner according to any one of claims 2 to 4, wherein the control unit of the air conditioner performs operation control for increasing a refrigerant condensing temperature when the heating operation is shifted to the defrosting operation.   6. The air conditioner according to claim 2, wherein the anti-freezing pipe is formed with a protrusion that is immersed in the drain water in the drain pan.

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