JP5104002B2 - Refrigeration cycle apparatus and air conditioner equipped with the same - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus including a bypass circuit for melting frost attached to an evaporator using a discharge gas refrigerant of a compressor.

  Conventionally, in this type of refrigeration cycle apparatus, frost adheres to the evaporator depending on the operating state, resulting in a reduction in capacity. That is, the high-temperature and high-pressure discharge gas refrigerant compressed by the compressor flows into the condenser via the four-way valve, and the refrigerant is condensed by performing heat exchange. The condensed refrigerant is depressurized by the expansion device, becomes a gas-liquid two-phase state, flows into the evaporator, evaporates by performing heat exchange, and is sucked into the compressor again through the four-way valve. Here, when the ambient temperature of the evaporator is low, frost gradually adheres to the evaporator, and the capacity decreases as the amount of frost attached increases.

  Then, if necessary, the operation to melt the frost attached to the evaporator is performed. As a method of melting this frost, the operation of each heat exchanger is reversed by switching the four-way valve to perform the reverse cycle operation. There is a way to melt frost. However, this method inherently reduces the temperature on the condenser side.

  Therefore, as a method not to perform reverse cycle operation, by providing a branch pipe in the discharge pipe through which the refrigerant discharged from the compressor flows, one of the refrigerant flows to the condenser and the other through a refrigerant control device such as an electromagnetic valve. There is a defrosting method in which frost adhering to the evaporator is melted by flowing into the evaporator (see, for example, Patent Document 1).

FIG. 2 shows a refrigeration cycle apparatus of a conventional air conditioner described in Patent Document 1. As shown in FIG. In FIG. 2, the outdoor unit B includes a compressor 1, a four-way valve 11, a throttle device 3, and an evaporator 4, and the indoor unit A includes a condenser 2 to constitute a refrigeration cycle during heating operation. And the discharge gas bypass 30 from the discharge pipe 1a to the pipe line between the expansion device 3 and the evaporator 4 is configured through the branch pipe 5 and the electromagnetic valve 6. In this configuration, frost adheres to the evaporator 4 when the heating operation is continued. Therefore, as the defrosting operation, when the operation of the heat exchangers of the condenser 2 and the evaporator 4 remains in the heating operation state and the electromagnetic valve 6 of the discharge gas bypass 30 is opened, the discharge gas refrigerant is transferred to the evaporator 4. The defrosting is performed by directly flowing, and the evaporator 4 can be defrosted while continuing the heating operation.
Japanese Utility Model Publication No. 60-10178

  However, in the conventional configuration, the branch pipe is generally provided in the direction in which the main flow of the refrigerant discharged from the compressor flows to the condenser. Basically, more refrigerant is provided in the condenser than the discharge gas bypass. In addition, when the discharge pressure is low, the refrigerant amount of the discharge gas refrigerant flowing into the evaporator is further reduced, so that the effect of the discharge gas bypass is reduced and the defrosting time is longer. If there is a problem or if a large amount of discharged gas refrigerant is allowed to flow, a refrigerant control device such as a solenoid valve must be selected with a very small flow path resistance, which increases the cost. Was.

  The present invention solves the above-mentioned conventional problems, enables a reduction in defrosting time, expands a selection range of a refrigerant control device such as a solenoid valve, improves design flexibility, and enables cost reduction. An object of the present invention is to provide a refrigeration cycle apparatus, and further to provide an air conditioner that includes the refrigeration cycle apparatus and improves comfort during heating operation.

  In order to solve the above-described conventional problems, the refrigeration cycle apparatus of the present invention is configured such that the flow rate at which the refrigerant discharged from the compressor flows through the discharge gas bypass during defrosting is greater than the flow rate through the four-way valve. . As a result, a large amount of discharged refrigerant flows on the bypass side, so that the temperature of the evaporator can be increased, the degree of superheat of the compressor and the temperature of the discharged refrigerant can be increased, and evaporation can be suppressed while suppressing a decrease in the capacity of the condenser. The defrosting time of the vessel can be shortened.

  The refrigeration cycle apparatus of the present invention can reduce the defrosting time by increasing the temperature rise of the evaporator because a large amount of discharged refrigerant flows to the discharge gas bypass side, and the refrigerant control device installed in the discharge gas bypass Since the degree of influence of the channel resistance is reduced, the degree of freedom in design is improved and the cost can be reduced accordingly. Moreover, in the air conditioner provided with the refrigeration cycle apparatus, it is possible to improve comfort by suppressing a decrease in room temperature during defrosting in heating operation.

  According to a first aspect of the present invention, a compressor, a four-way valve, a condenser, a throttling device, and an evaporator are connected by piping to form a refrigeration cycle. The suction pipe of the compressor, the throttling device, and evaporation A discharge gas bypass that bypasses the discharge refrigerant from a discharge pipe that connects the compressor and the four-way valve to one or both of the evaporator pipes that connect the evaporator, and a discharge refrigerant that bypasses the discharge gas bypass And a refrigerant control device that can freely flow the frost adhering to the evaporator to dissolve and defrost, and the flow rate that flows by bypassing the refrigerant discharged from the compressor during defrosting is the four-way It is a refrigeration cycle apparatus configured to be larger than the flow rate flowing to the valve.

  Thereby, since a large amount of discharged refrigerant flows on the discharge gas bypass side, the temperature of the evaporator can be increased, or the degree of superheat of the compressor and the temperature of the discharged refrigerant can be increased, and accordingly the temperature of the evaporator can be further increased. The defrosting time of the evaporator can be shortened while suppressing a decrease in capacity in the condenser. Moreover, since the influence degree of the flow path resistance of the refrigerant control device installed in the discharge gas bypass is reduced, the degree of freedom in design is improved and the cost can be reduced accordingly.

  In the second invention, in particular, the flow resistance of the discharge gas bypass of the refrigeration cycle apparatus of the first invention is made smaller than the flow resistance on the condenser side. It is possible to increase the flow rate flowing to the side four-way valve.

  In the third invention, in particular, the discharge gas bypass of the refrigeration cycle apparatus of the first invention is provided with a branch pipe in the discharge pipe, and the refrigerant discharged from the compressor is more dynamic than the four-way valve in the direction of the discharge gas bypass. Because the dynamic pressure component of the discharged refrigerant is greatly applied to the bypass side, the refrigerant diversion ratio in the branch pipe is larger from the four-way valve side to the discharge gas bypass side, and the discharge gas bypass side The flow rate of the refrigerant can be increased. Further, even if there is a refrigerant control device installed in the discharge gas bypass, the circulation rate can be maintained, that is, the influence of the flow path resistance of the refrigerant control device can be reduced.

  In the fourth invention, in particular, the discharge gas bypass of the refrigeration cycle apparatus according to the first to third inventions is provided, and the discharge pipe is provided with a T-shaped branch pipe, and the discharge refrigerant of the compressor is straight in the direction of the discharge gas bypass. The flow resistance of the discharge gas bypass can be made smaller than the flow path resistance on the condenser side, and the discharge refrigerant of the compressor can be connected to the discharge gas bypass. The dynamic pressure component can be applied to the direction more than the direction of the four-way valve.

  In the fifth invention, in particular, the outlet of the discharge gas bypass of the first to fourth refrigeration cycle apparatuses is connected to the portion where the outlet of the refrigeration cycle joins the piping of the refrigeration cycle so that the flow from the bypass becomes linear by a T-shaped tube. Therefore, the flow resistance of the discharge gas bypass can be made smaller than the flow resistance on the condenser side, and the flow rate of the refrigerant on the bypass side can be increased.

  In the sixth aspect of the invention, in particular, the pipe length of the discharge gas bypass of the first to fifth refrigeration cycle apparatuses is shorter than the pipe length of the condenser side. It can be made smaller than the resistance, and the flow rate of the refrigerant on the bypass side can be increased.

  In particular, the seventh aspect of the present invention is such that the pipe diameter of the discharge gas bypass of the first to sixth refrigeration cycle apparatuses is made equal to or larger than the pipe diameter on the condenser side, and the flow resistance of the discharge gas bypass is reduced to the condenser. The flow resistance of the refrigerant on the bypass side can be increased because the flow resistance on the side can be made smaller.

  In the eighth aspect of the invention, in particular, 50% to 90% of the discharged refrigerant flows in the discharge gas bypass of the first to seventh refrigeration cycle apparatuses, whereby a large amount of discharged refrigerant flows on the bypass side. Therefore, it is possible to increase the temperature of the evaporator, or to increase the superheat degree of the compressor and the temperature of the discharged refrigerant, and further increase the temperature of the evaporator. It is possible to shorten the defrosting time.

  9th invention is an air conditioner which has the indoor unit and outdoor unit which were each equipped with the air blower, and was equipped with the refrigeration cycle apparatus as described in any one of Claims 1-8, and defrost time With the refrigeration cycle device that can shorten the temperature, a decrease in room temperature during defrosting in heating operation can be suppressed, and comfort can be improved.

  In the tenth aspect of the invention, in particular, the indoor unit of the air conditioner of the ninth aspect of the invention is provided with an auxiliary heating device, and the room temperature decrease is further suppressed by compensating for the decrease in heating capacity during defrosting in heating operation. And comfort can be further improved.

  Hereinafter, embodiments of the refrigeration cycle apparatus of the present invention will be described with reference to the drawings as examples mounted on an air conditioner. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigerant system diagram of the refrigeration cycle apparatus according to Embodiment 1 of the present invention and shows a refrigerant flow as an air conditioner (in the direction of a solid arrow during heating operation). In FIG. 1, a compressor 1 that compresses refrigerant, a four-way valve 11 that changes the flow of refrigerant, a condenser 2 that condenses high-pressure and high-temperature refrigerant, a throttling device 3 that depressurizes condensed refrigerant, and evaporates the reduced refrigerant. The evaporator 4 is connected by piping in order, and the normal refrigeration cycle is comprised. Here, the condenser 2 is provided in the indoor unit A, and the others are provided in the outdoor unit B. The indoor unit A further includes an indoor fan 7 and an electric heater 9, and the outdoor unit B includes the outdoor fan 8. I have.

  In this Embodiment 1, the 1st discharge gas bypass 31 which branches the discharge gas refrigerant | coolant from the compressor 1 with the discharge pipe 1a before the four-way valve 11 is provided, and further branches from there, and the expansion device 3 A second discharge gas bypass 32 that bypasses the evaporator pipe 4 a between the evaporator 4 and a third discharge gas bypass 33 that bypasses the suction pipe 1 b of the compressor 1 is provided. That is, here, the discharge gas bypass is composed of the first discharge gas bypass 31, the second discharge gas bypass 32, and the third discharge gas bypass 33.

A refrigerant control device 40 is provided in the middle of the first discharge gas bypass 31 to allow the discharge gas refrigerant to flow arbitrarily, and the flow of the refrigerant is controlled as necessary. Further, an evaporator bypass flow rate adjustment pipe 32a and a check valve 32b are provided in the middle of the second discharge gas bypass 32. Further, an intake bypass flow rate adjustment pipe 33 a is provided in the middle of the third discharge gas bypass 33 to adjust the flow rate balance between the second discharge gas bypass 32 and the third discharge gas bypass 33.

  Further, the branch of the first discharge gas bypass 31 in the discharge pipe 1 a is performed by including a substantially T-shaped branch pipe 51. In this branch pipe 51, the refrigerant discharged from the compressor 1 flows linearly in the direction of the first discharge gas bypass 31 (arrow D1), and bends substantially perpendicularly to the direction of the four-way valve 11 (arrow D2). It is configured.

  Further, T-shaped pipes 52 and 53 similar to the branch pipe 51 are respectively joined at the junction to the evaporator pipe 4 a at the outlet of the second discharge gas bypass 32 and at the junction to the suction pipe 1 b at the outlet of the third discharge gas bypass 33. It has. That is, in the merge of the T-shaped pipe 52 on the heat exchanger pipe 4a side, the flow as the evaporator pipe 4a from the expansion device 3 is bent substantially at right angles (arrow D3), and the second discharge gas bypass 32 is configured. Is connected so as to flow linearly to the evaporator pipe 4a (arrow D4). Further, when the T-shaped pipe 53 on the suction pipe 1b side is merged, the original flow as the suction pipe 1b from the four-way valve 11 is bent substantially at a right angle (arrow D5), and from the third discharge gas bypass 33 Are connected to the suction pipe 1b so as to flow linearly (arrow D6).

  About the air conditioner provided with the refrigerating-cycle apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. First, at the time of heating operation, as indicated by a solid line arrow, the high-temperature and high-pressure discharge gas refrigerant compressed by the compressor 1 flows into the condenser 2 of the indoor unit A through the four-way valve 11 and performs heat exchange. Is condensed and the room is heated. The condensed refrigerant enters the outdoor unit B, is decompressed by the expansion device 3, enters a gas-liquid two-phase state, flows into the evaporator 4, evaporates by performing heat exchange, and absorbs outdoor heat. Then, it is sucked again into the compressor 1 through the four-way valve 11. During this normal heating operation, the refrigerant control device 40 is closed. Here, when the ambient temperature of the evaporator 4 is low, frost gradually adheres to the evaporator 4, and the heating capacity decreases as the amount of frost attached increases.

  Therefore, when the amount of frost formation has increased to a predetermined amount, the refrigerant control device 40 provided in the first discharge gas bypass 31 is opened, and the discharge gas refrigerant flows through the second discharge gas bypass 32 and the third discharge gas bypass 33. Thus, the evaporator 4 is defrosted. In the second discharge gas bypass 32, the melting of frost is promoted by increasing the temperature of the evaporator 4. Further, in the third discharge gas bypass 33, the temperature of the compressor 1 and the discharge gas refrigerant is increased by increasing the dryness of the compressor 1, and thereby the temperature of the evaporator 4 is further increased. . When configured in this way, the four-way valve 11 is defrosted in the heating operation state without switching, and the heating capacity is reduced, but the room is heated as compared with the system that defrosts in the reverse cycle. Temperature change can be reduced, and a decrease in comfort can be suppressed.

  Note that the first discharge gas bypass 31 does not necessarily have to be divided into both the second discharge gas bypass 32 and the third discharge gas bypass 33 and flow the discharge gas refrigerant. It is possible to defrost in the heating operation state. That is, instead of the refrigerant control device 40 having the above-described configuration, a refrigerant control device may be provided in each of the second discharge gas bypass 32 and the third discharge gas bypass 33, and the control may be performed according to the operating condition or the like. . Further, as the discharge gas bypass, a configuration in which only the first discharge gas bypass 31 and the second discharge gas bypass 32 are combined, or a configuration in which the first discharge gas bypass 31 and the third discharge gas bypass 33 are combined may be used.

Next, in the first embodiment, the discharge gas refrigerant from the compressor 1 is used as the first discharge gas bypass 3.
When circulating from 1 to the second discharge gas bypass 32 and the third discharge gas bypass 33, a T-shaped branch pipe 51 is provided at the branch of the first discharge gas bypass 31 in the discharge pipe 1a of the compressor 1. Yes. In particular, the branch pipe 51 is configured such that the refrigerant discharged from the compressor 1 flows linearly in the direction of the first discharge gas bypass 31 and is bent at a right angle in the direction of the four-way valve 11. With this configuration, the discharge gas refrigerant has a larger dynamic pressure component in the direction of the first discharge gas bypass 31 than in the direction of the four-way valve 11. Then, due to the action of the dynamic pressure, the refrigerant distribution ratio in the branch pipe 51 becomes larger on the first discharge gas bypass 31 side, and the flow rate of the discharge gas refrigerant on the first discharge gas bypass 31 side can be increased.

  Thereby, the frost adhering to the evaporator 4 can be melt | dissolved in a short time, a room temperature change can be decreased more, and the fall of comfort can be suppressed more. In particular, by setting the flow rate of the discharge gas refrigerant flowing to the first discharge gas bypass 31 to be larger than the flow rate of flowing to the four-way valve 11, even if the room temperature temporarily decreases due to a decrease in heating capacity, it is even shorter. By completing the defrosting, a great effect of suppressing a decrease in comfort can be obtained.

  Further, T-tubes 52 and 53 are also used on the merging side of the suction pipe 1b and the evaporator pipe 4a, and the outlet of the second discharge gas bypass 32 and the outlet of the third discharge gas bypass 33 join the refrigeration cycle pipe. The flow rate from the discharge pipe 1a to the first discharge gas bypass 31 is set to be higher by connecting the pipes so that the flow at the pipes is linear and making the flow path resistance small so as not to disturb the flow as much as possible. Is possible. Note that the T-shaped branch pipe 51 and the T-shaped pipes 52 and 53 do not necessarily need to be completely T-shaped, and may be any one that can configure the discharge gas bypass side with less flow path resistance.

  As described above, the dynamic pressure component of the discharge gas refrigerant is configured to act on the first discharge gas bypass 31 side, or the flow resistance is reduced even in the merge, so that the flow can be smoothly performed. The refrigerant control device 40 is configured such that the branching ratio in the branch pipe 51 increases toward the first discharge gas bypass 31 and the influence of the flow path resistance of the refrigerant control device 40 installed in the first discharge gas bypass 31 decreases. The design margin can be increased, thereby reducing the cost.

  Further, the pipe length of the refrigerant pipe on the first discharge gas bypass 31 side is made shorter than the pipe length on the condenser 2 side, or the pipe diameter is also made equal to or larger than that, so that the flow path resistance on the discharge gas bypass side is increased. It is possible to set a larger flow rate from the discharge pipe 1a to the first discharge gas bypass 31 by reducing the flow path resistance on the condenser 2 side.

  As described above, the flow rate from the discharge pipe 1a to the first discharge gas bypass 31 is reduced by making the flow resistance on the discharge gas bypass side smaller than the flow resistance on the condenser 2 side. Can be set higher than the flow rate flowing to the four-way valve on the condenser side. Then, the temperature of the evaporator 4 is increased by configuring the flow rate of the discharge gas refrigerant of the compressor 1 flowing to the first discharge gas bypass 31 to be greater than the flow rate of flowing to the four-way valve 11 during defrosting, A larger temperature rise of the evaporator 4 can be achieved also by the degree of superheat of the compressor 1 and the temperature rise of the discharge gas refrigerant, and the defrosting time of the evaporator 4 can be further increased while suppressing a decrease in the capacity of the condenser 2. It can be shortened. Further, since the degree of influence of the flow path resistance of the refrigerant control device 40 installed in the first discharge gas bypass 31 is reduced, the degree of freedom in design is improved and the cost can be reduced accordingly. Furthermore, it becomes possible to provide the air conditioner which improved comfort by providing the refrigeration cycle apparatus of the above structures.

The ratio of the diversion to the first discharge gas bypass 31 is usually less than 50%, and the defrosting time for melting the frost is also relatively long. In the first embodiment, the first discharge gas bypass is used. 31 is configured such that 50% to 90% of the discharged refrigerant flows, so that defrosting is completed in about 5 minutes to 7 minutes depending on the ambient temperature condition. Thereby, although the circulation amount of the refrigerant | coolant to the condenser 2 of the indoor unit A falls, the fall of heating capability is suppressed by enlarging the dryness of the compressor 1 and raising the temperature of discharge gas refrigerant | coolant etc. You can also Furthermore, if the indoor unit A is provided with, for example, an electric heater 9 as an auxiliary heating device, it is possible to compensate for a decrease in heating capacity in the refrigeration cycle, and to further suppress a decrease in room temperature and further improve comfort.

  As described above, in the refrigeration cycle apparatus according to the present invention, since the dynamic pressure component of the discharged refrigerant is applied to the bypass pipe side, the branching ratio in the branch pipe portion is greatly increased to the bypass pipe side and installed in the bypass pipe. In addition to cost reduction due to improved design flexibility due to the reduced influence of flow path resistance of the refrigerant control device, a large amount of discharged refrigerant flows to the bypass pipe side, so the defrosting time can be shortened. Therefore, it can be applied not only to air conditioners but also to applications such as refrigerators, vending machines, and heat pump water heaters.

Refrigerant system diagram of refrigeration cycle apparatus in Embodiment 1 of the present invention Refrigerant system diagram of conventional air conditioner

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 1a Discharge pipe 1b Suction pipe 2 Condenser 3 Throttle device 4 Evaporator 4a Evaporator piping 7 Indoor fan 8 Outdoor fan 9 Electric heater 11 Four-way valve 31 1st discharge gas bypass 32 2nd discharge gas bypass 32a Flow rate adjustment pipe 32b Check valve 33 Third discharge gas bypass 33a Flow rate adjustment pipe 40 Refrigerant control device 51 Branch pipe 52, 53 T-shaped pipe A Indoor unit B Outdoor unit

Claims (10)

A compressor, a four-way valve, a condenser, a throttling device, and an evaporator are connected by piping to form a refrigeration cycle, and the suction pipe of the compressor, the throttling device, and an evaporator are connected to the evaporator. A discharge gas bypass that bypasses the discharge refrigerant from a discharge pipe that connects the compressor and the four-way valve, and a discharge refrigerant that flows through the discharge gas bypass arbitrarily And a refrigerant control device capable of melting and defrosting frost adhering to the evaporator, and a first discharge gas bypass for branching the discharge gas from the compressor at a discharge pipe before the four-way valve And a second discharge gas bypass branched from the first discharge gas bypass and connected to an evaporator pipe between the expansion device and the evaporator, and a third discharge gas connected to the suction pipe of the compressor Bypass and first discharge The bypass has a refrigerant control device for arbitrarily controlling the discharge gas refrigerant flow rate, the second discharge gas bypass has an evaporator bypass flow rate adjustment pipe and a check valve, and the third discharge gas bypass has an intake bypass flow rate adjustment A branch of the first discharge gas bypass in the discharge pipe is a substantially T-shaped branch pipe, and the branch pipe causes the refrigerant discharged from the compressor to flow linearly in the direction of the first discharge gas bypass, In the direction of the four-way valve, it is connected so as to be bent at a substantially right angle, and further at the junction of the second discharge gas bypass at the outlet to the evaporator pipe and at the junction of the third discharge gas bypass at the outlet with the suction pipe It is linearly flow from the first discharge gas bypass, and the second discharge gas bypass, and connected to bent the other flow substantially perpendicular, discharge cooling of the compressor during defrosting The flow rate flowing through the discharge gas bypass is larger than the flow rate flowing to the four-way valve, and the flow rate flowing through the discharge gas bypass is also the portion where the refrigerant from the evaporator joins the discharge gas bypass. A refrigeration cycle apparatus configured to have a higher flow rate than the refrigerant to be used. The refrigeration cycle apparatus according to claim 1, wherein the flow path resistance of the discharge gas bypass is made smaller than the flow path resistance on the condenser side. 2. A refrigeration cycle apparatus according to claim 1, wherein a branch pipe is provided in the discharge pipe, and the refrigerant discharged from the compressor is connected so that a dynamic pressure component acts more in the direction of the discharge gas bypass than in the direction of the four-way valve. . The discharge pipe is provided with a T-shaped branch pipe so that the refrigerant discharged from the compressor flows linearly in the direction of the discharge gas bypass and bends in the direction of the four-way valve. The refrigeration cycle apparatus according to any one of? 5. The apparatus according to claim 1, wherein the outlet of the discharge gas bypass is connected to a location where the outlet of the discharge gas bypass joins the piping of the refrigeration cycle so that the flow from the bypass becomes linear by a T-shaped tube. Refrigeration cycle equipment. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein a pipe length of the discharge gas bypass is shorter than a pipe length on the condenser side. The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein a pipe diameter of the discharge gas bypass is made equal to or greater than a pipe diameter on the condenser side. The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein 50% to 90% of the discharged refrigerant flows through the discharge gas bypass. An air conditioner comprising an indoor unit and an outdoor unit each having a blower, and the refrigeration cycle apparatus according to any one of claims 1 to 8. The air conditioner according to claim 9, wherein the indoor unit includes an auxiliary heating device.