JP2005300157A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable system capable of preventing a trouble from being generated by a deterioration product resulting from a refrigerating machine oil, in an air conditioner having a refrigerating circuit using a refrigerant of a hydrofluorocarbon as a hydraulic fluid, and using an oil compatible with the refrigerant as the refrigerating machine oil. <P>SOLUTION: A compressor 1 of a heat source unit A, a selector valve 2 and a heat source unit side heat exchanger 3, and the second contraction device 6, and the first contraction devices 8b, 8c, 8d indoor units B, C, D and indoor side heat exchangers 7b, 7c, 7d are branched from a refrigerant pipe between a delivery part of the compressor 1 in a main refrigerating circuit connected by a liquid side connection refrigerant pipe 9 and a gas side connection refrigerant pipe 10 and the selector valve 2, and a bypass circuit 15 is provided to be connected to the refrigerant pipe between the compressor 1 and the selector valve 2 and an accumulator 4, via a bypass heat exchanger 18 for cooling the refrigerant, a drier 16 for absorbing moisture and a bypass contraction device 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an air conditioner that uses a hydrofluorocarbon refrigerant as a working medium and oil that is compatible with the refrigerant as refrigeration oil.

  FIG. 28 is a refrigerant circuit diagram of a conventional air conditioner, in which A is a heat source unit, B, C, and D are indoor units, 1 is a compressor, 2 is a switching valve, and 3 is a heat source unit side heat exchanger. 4 is an accumulator, 5 is an oil return hole of the accumulator 4, 6 is a heating expansion device (hereinafter referred to as a second expansion device), 7b, 7c and 7d are indoor unit side heat exchangers, 8b and 8c. 8d is a cooling-time expansion device (hereinafter referred to as a first expansion device), 9 is one end of the heat source unit A on the heat source unit side heat exchanger 3 side, and the first expansion unit 8b of the indoor units B, C, and D, The liquid side connection refrigerant pipes 10 for connecting one end on the 8c, 8d side are one end on the switching valve 2 side of the heat source unit A and the indoor unit side heat exchangers 7b, 7c, 7d of the indoor units B, C, D. Gas-side connecting refrigerant pipes that connect one end of the side, 11 and 12 are used to store a desiccant mainly composed of synthetic zeolite in a cylindrical container or pipe. Was, dryer to moisture absorption of moisture mixed in the refrigerant circuit, 13,14b, 14c, 14d is a sludge filter to trap sludge built fine mesh filter cylindrical container and the pipe.

  Next, the flow of the refrigerant will be described with reference to the drawings. In the figure, solid arrows indicate the flow during cooling, and broken arrows indicate the flow during heating. First, at the time of cooling, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 flows into the heat source machine side heat exchanger 3 through the switching valve 2, and is condensed by exchanging heat with air and the like. Becomes a refrigerant. Furthermore, the second expansion device 6 that is fully open during cooling and the liquid side connection refrigerant pipe 9 are passed through to reach the indoor units B, C, and D, and the degree of superheat at the outlets of the indoor unit side heat exchangers 7b, 7c, and 7d is increased. The first throttling devices 8b, 8c, and 8d controlled so as to be within a certain range are throttling to a low-pressure gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant flows into the indoor unit side heat exchangers 7b, 7c, and 7d, exchanges heat with indoor air and gasifies, and forms the gas side connection refrigerant pipe 10, the switching valve 2, and the accumulator 4. It returns to the compressor 1 through this. The refrigerating machine oil inside the accumulator 4 returns to the compressor 1 through the oil return hole 5 together with the liquid refrigerant.

  At the time of heating, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 reaches the indoor units B, C, D through the switching valve 2 and the gas side connection refrigerant pipe 10, and the indoor unit side heat exchangers 7b, 7c. , 7d, and heat exchange with indoor air to condense and become a high-temperature and high-pressure liquid refrigerant. The liquid refrigerant that has exited the indoor heat exchangers 7b, 7c, and 7d is slightly decompressed by the first expansion devices 7b, 7c, and 7d that are almost fully open, and passes through the liquid-side connection refrigerant pipe 9 to form the second expansion device 6. Where the pressure is reduced to a low-pressure gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant flows into the heat source machine side heat exchanger 3, exchanges heat with air and the like, and gasifies, and returns to the compressor 1 through the switching valve 2 and the accumulator 4. The refrigerating machine oil inside the accumulator 4 returns to the compressor 1 through the oil return hole 5 together with the liquid refrigerant.

  In the refrigerant circuit as described above, a hydrofluorocarbon refrigerant has recently been used as a working medium instead of a hydrochlorofluorocarbon refrigerant. However, since the hydrofluorocarbon refrigerant does not have a chlorine component, it is not compatible with conventional mineral oil used as refrigerating machine oil, and is separated from the liquid refrigerant inside the accumulator 4 and floats on the top. The refrigeration oil does not return to the compressor 1 from the oil return hole 5. Therefore, in an air conditioner in which a large amount of liquid refrigerant is stored in an accumulator and the compressor 1 is driven by a motor, the polyester is compatible with a hydrofluorocarbon refrigerant and has excellent insulating properties. Oils or polyether oils are generally used.

  However, these polyester oils and polyether oils absorb moisture and are hydrolyzed when subjected to high temperature conditions such as the sliding portion of the compressor 1 or when processing oxygen or refrigerant circuit components. There is a risk of deterioration due to the remaining components of the processing oil and cleaning agent mixed in. In particular, among the additives used in polyether oil, antiwear agents are generally highly active ester type, and even if the polyether oil does not hydrolyze, the additive is hydrolyzed and compressed in a high temperature state. Thermal degradation occurs at the sliding portion of the machine 1.

  These deteriorated products generated at that time are either present as solids in the refrigerating machine oil or dissolved and present. When both the solid component and the dissolved component are discharged from the compressor 1, the high-temperature and high-pressure gas refrigerant is mixed into the discharge gas together with the refrigerating machine oil and discharged into the refrigerant circuit. The deterioration product of the refrigeration oil flows into the condenser (the heat source side heat exchanger 3 during cooling and the indoor unit side heat exchangers 7b, 7c and 7d during heating) together with the refrigerant, and the refrigerant is liquefied here. When the refrigerant is liquefied and the refrigerant concentration is increased, the deterioration product of the refrigerating machine oil that has been dissolved in the refrigerating machine oil that has flown with the refrigerant cannot be dissolved, and is deposited as a solid and directly on the pipe wall of the pipe. Things appear.

  These newly deposited deterioration products flow into the first expansion devices 8b, 8c and 8d and the second expansion device 6 together with the deterioration products originally present as solids. Among the remaining components of processing oil and cleaning agent that are mixed when processing refrigerant circuit components, those that are not compatible with the hydrofluorocarbon refrigerant form a film on the pipe wall, and this non-phase The dissolved component becomes a binder, and the deterioration product of the refrigerating machine oil adheres to the pipe wall of the pipe. In particular, in a throttling device such as a capillary tube in which the flow path cross-sectional area suddenly changes, the flow can stagnate, and the deterioration product of the refrigerating machine oil is markedly attached. In this way, the refrigeration oil deterioration product existing as a solid in the refrigeration oil adheres to the first expansion devices 8b, 8c, 8d and the second expansion device 6 as sludge. Further, when liquid refrigerant is accumulated in the accumulator 4, the degradation product that is a solid or dissolved component of the refrigerating machine oil deposits and adheres to the oil return hole 5 similarly to the expansion device.

  As measures against sludge adhesion as described above, the dryers 11 and 12 in which a desiccant mainly composed of synthetic zeolite or the like is incorporated in a cylindrical container or pipe are connected to a refrigerant pipe between the switching valve 2 and the accumulator 4; And a sludge filter provided in a liquid-side connection refrigerant pipe 9 between the first throttling devices 8b, 8c, 8d and the second throttling device 6, and having a fine mesh-like filter built in a cylindrical container or pipe Is a refrigerant pipe between the heat source device side heat exchanger 3 and the second expansion device 6, and a refrigerant between the indoor side heat exchangers 7b, 7c, 7d and the first expansion devices 8b, 8c, 8d. Provided in the piping.

  A dryer 11 provided between the switching valve 2 and the accumulator 4 is connected to the switching valve 2 from the indoor unit side heat exchangers 7b, 7c and 7d during cooling and from the heat source unit side heat exchanger 3 during heating. The gas refrigerant flows in through and the moisture contained in the gas refrigerant is absorbed. The dryer 12 provided in the liquid side connection refrigerant pipe 9 between the first expansion devices 8b, 8c, 8d and the second expansion device 6 is almost fully opened from the heat source unit side heat exchanger 3 during cooling. The second expansion device 6 is heated, and during heating, the indoor unit side heat exchangers 7b, 7c, and 7d are almost fully opened through the first expansion devices 8b, 8c, and 8d, and the liquid is slightly depressurized. A single-phase refrigerant flows in. Accordingly, the pressure loss in the dryer 12 is small, the flow is quiet, and moisture is sufficiently absorbed.

  In the sludge filter 13 provided in the refrigerant pipe between the heat source machine side heat exchanger 3 and the second expansion device 6, the deterioration product of the refrigeration oil that flows into the heat source machine side heat exchanger 3 together with the refrigerant during cooling The deterioration product dissolved in the refrigerating machine oil deposited and adhered by the liquefaction of the refrigerant in the heat source apparatus side heat exchanger 3 and the decrease in the flow velocity is captured as sludge. Further, in the sludge filters 14b, 14c, 14d provided in the refrigerant pipe between the indoor side heat exchangers 7b, 7c, 7d and the first expansion devices 8b, 8c, 8d, the indoor side heat exchanger 7b during heating is used. , 7c, 7d and the deterioration product of the refrigerating machine oil that flowed together with the refrigerant, and dissolved in the refrigerating machine oil deposited and adhered due to the liquefaction of the refrigerant in the indoor heat exchangers 7b, 7c, 7d and the decrease in the flow velocity. Deteriorated products are trapped as sludge.

JP-A-9-138014

  In the conventional air conditioner using the dryer as described above, when the refrigerant gas passes through the dryer 11, a suction pressure loss occurs, the evaporation capability is reduced, and conversely, the reduction of the evaporation capability is to be suppressed. It is necessary to increase the size of the dryer 11. Further, if sufficient non-oxidative brazing is not performed at the time of construction of the refrigerant pipe, an oxidation scale is generated, which flows into the dryers 11 and 12 during operation, and the flow path is blocked or the dryer 11 is crushed. There was a risk of doing. Furthermore, there is a risk that the dryers 11 and 12 may be crushed due to a sudden liquid back generated during a transient operation such as compressor start-up, air conditioning switching, defrost start / end, or a strong flow of refrigerant liquid.

  Moreover, in the conventional air conditioning apparatus which installed the above sludge filters, between the heat source machine side heat exchanger 3 and the 2nd expansion device 6, and indoor side heat exchangers 7b, 7c, 7d, and 1st There is a problem that it is necessary to install a sludge filter at all positions between the expansion devices 8b, 8c and 8d, and the overall size of the air conditioner increases. In addition, the sludge captured by the sludge filter 13 between the heat source device side heat exchanger 3 and the second expansion device 6 during cooling is separated when the flow is switched to heating, and the heat source device side heat exchanger 3 Then, the oil flows into the accumulator 4 via the switching valve 2 and the oil return hole 5 is closed. Similarly, sludge captured by the sludge filters 14b, 14c, 14d between the indoor heat exchangers 7b, 7c, 7d and the first expansion devices 8b, 8c, 8d during heating is separated when the flow is switched to cooling. Then, the oil flows into the accumulator 4 through the indoor heat exchangers 7b, 7c, 7d and the switching valve 2, and the oil return hole 5 is closed. Furthermore, if sufficient non-oxidative brazing is not performed at the time of construction of the refrigerant pipe, an oxidation scale is generated, which flows into the sludge filters 13, 14b, 14c, and 14d during operation, and the flow path is blocked. There was also a risk of damaging the sludge filter.

  The present invention has been made to solve the above-described problems. Even if a hydrofluorocarbon refrigerant is used as a working fluid and an oil compatible with the refrigerant is used as a refrigerator oil, the refrigerator oil can be used. It is an object of the present invention to obtain a highly reliable air conditioner that is free from defects due to this, even if a deteriorated product is generated.

  An air conditioner according to a first aspect of the present invention includes a main refrigerant circuit including a compressor, a condenser, a throttle device, and an evaporator, and uses a hydrofluorocarbon refrigerant as a working medium. In an air conditioner that uses oil compatible with refrigeration oil as a refrigerating machine oil, it branches off from a refrigerant pipe between the condenser and the expansion device, passes through a dryer and a bypass expansion device that absorbs moisture, and A bypass circuit connected to the refrigerant pipe between the expansion device and the compressor is provided.

  An air conditioner according to a second aspect of the present invention includes a main refrigerant circuit including a compressor, a condenser, a throttle device, and an evaporator, and uses a hydrofluorocarbon refrigerant as a working medium. In an air conditioner that uses oil compatible with the refrigerant as refrigerant oil, the refrigerant pipe on the suction side of the compressor branches from the refrigerant pipe on the discharge side of the compressor and passes through a dryer and a bypass throttle device that absorbs moisture A bypass circuit connected to is provided.

  The air conditioner according to a third aspect of the present invention is the air conditioner according to the first or second aspect, wherein a bypass heat exchanger for cooling the refrigerant flowing into the dryer is provided in the middle of the bypass.

  According to a fourth aspect of the present invention, there is provided an air conditioner comprising a compressor, a switching valve, a heat source apparatus side heat exchanger and a heating time expansion apparatus, and a cooling time expansion apparatus and an indoor side heat exchanger. A liquid-side refrigerant pipe that connects one end of the heat source unit on the side of the expansion device during heating and one end of the indoor unit on the side of the expansion unit during cooling, one end on the switching valve side of the heat source unit, and one end of the indoor unit A main refrigerant circuit having a gas-side refrigerant pipe connecting one end of the indoor heat exchanger is provided, and a hydrofluorocarbon refrigerant is used as a working medium, and oil compatible with the refrigerant is refrigerated. In an air conditioner used as machine oil, the compressor intake section includes a dryer that branches off from the liquid side connection refrigerant pipe, absorbs moisture, a bypass expansion device, and a bypass heat exchanger that cools refrigerant flowing into the dryer. And the switching valve It is provided with a bypass circuit connected to the refrigerant pipe between.

  An air conditioner according to a fifth aspect of the present invention includes a heat source unit including a compressor, a switching valve, and a heat source unit side heat exchanger, an indoor unit including a throttle unit and an indoor side heat exchanger, and a heat source of the heat source unit. A liquid side connection refrigerant pipe connecting one end on the unit side heat exchanger side and one end on the expansion device side of the indoor unit, one end on the switching valve side of the heat source unit, and one on the indoor side heat exchanger side of the indoor unit In an air conditioner comprising a main refrigerant circuit having a gas-side connecting refrigerant pipe connecting one end, using a hydrofluorocarbon refrigerant as a working medium, and using oil compatible with the refrigerant as refrigerating machine oil The compressor suction section and the switching valve are branched from a refrigerant pipe between the compressor discharge section and the switching valve, and the refrigerant suction section and the switching valve are passed through a bypass heat exchanger that cools the refrigerant, a dryer that absorbs moisture, and a bypass throttle device. Connected to the refrigerant piping between It is provided with a bypass circuit that.

  According to a sixth aspect of the present invention, there is provided an air conditioner according to any one of the first to fifth aspects, wherein a hydrofluorocarbon-based mixed refrigerant is used as a working medium and is provided at an inlet portion of a bypass throttling device. The first temperature detection means provided, the second temperature detection means provided downstream of the bypass throttling device in the middle of the bypass, the suction pressure detection means provided in the compressor suction portion, and the first and second And a composition calculating means for calculating the composition of the refrigerant based on the detected value of the suction pressure detecting means.

  An air conditioner according to a seventh aspect of the present invention is the air conditioning apparatus according to any one of the first to sixth aspects, wherein the mounting posture of the dryer is downward with respect to the flow direction.

  According to the first aspect of the present invention, the refrigerant is branched from the refrigerant pipe between the condenser and the expansion device, and is connected between the expansion device and the compressor of the main refrigerant circuit via the dryer and the bypass expansion device that absorb moisture. Since the bypass circuit connected to the refrigerant pipe is provided, moisture is absorbed by the dryer in the bypass circuit, and the amount of water in the refrigerant / refrigerant oil decreases downstream of the dryer. This rate is sufficiently faster than the rate of hydrolysis degradation of the polyester oil, and has the effect of inhibiting hydrolysis and inhibiting the generation of sludge components in the compressor. Further, by providing the dryer in the middle of the bypass circuit, the impact of the flow through the dryer can be reduced, and the dryer is less likely to be crushed.

  According to a second aspect of the present invention, a bypass circuit is provided that branches from the refrigerant pipe on the discharge side of the compressor and is connected to the refrigerant pipe on the suction side of the compressor via a dryer that absorbs moisture and a bypass throttling device. Therefore, in addition to the effect of the invention of claim 1, in the cycle in which the refrigerant discharged from the compressor returns to the compressor through a bypass, the heat source unit side heat exchanger, the indoor unit side heat exchanger, the liquid Because it is a very short cycle that does not go through the side connection refrigerant pipe and the gas side connection refrigerant pipe, the response is good and the transient state where no liquid is supplied to the dryer is very short. In addition, the oxidation scale generated when the non-oxidizing brazing is not performed sufficiently during the construction of the liquid side refrigerant pipe or the gas side refrigerant pipe does not flow into the dryer during operation. The road Busy or there is an effect that also eliminates the risk of or crushing the dryer.

  According to Claim 3 of this invention, in the invention of Claim 1 or 2, since the bypass heat exchanger for cooling the refrigerant flowing into the dryer is provided in the middle of the bypass, the effect of the invention of Claim 1 or 2 In addition, the refrigerant flowing into the dryer is cooled by the bypass heat exchanger, so that the refrigerant flowing into the dryer can be easily changed to a liquid state even when the compressor is started up or during a transient operation such as defrosting. Since the refrigerant has a low temperature, the moisture saturation solubility in the refrigerant is low, and in the coexistence with the dryer, moisture is more easily transferred to the dryer than in the refrigerant. And the hydrolysis of the refrigerating machine oil can be suppressed.

  According to the fourth aspect of the present invention, the compressor suction portion includes a dryer that branches off from the liquid side connection refrigerant pipe, absorbs moisture, a bypass expansion device, and a bypass heat exchanger that cools the refrigerant flowing into the dryer. Since the bypass circuit connected to the refrigerant pipe between the control valve and the switching valve is provided, the same effects as in the first and third aspects are obtained.

  According to the fifth aspect of the present invention, the compressor branches via the bypass heat exchanger that cools the refrigerant, the dryer that absorbs moisture, and the bypass throttle device that branches off from the refrigerant pipe between the compressor discharge section and the switching valve. Since a bypass circuit connected to the refrigerant pipe between the suction portion and the switching valve is provided, the same effects as in the second and third aspects are obtained.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, a hydrofluorocarbon mixed refrigerant is used as the working medium, and the first provided in the inlet portion of the bypass throttling device. 1 temperature detection means, second temperature detection means provided downstream of the bypass throttle device in the middle of bypass, suction pressure detection means provided in the compressor suction section, and the first and second temperature detections And a composition calculating means for calculating the composition of the refrigerant based on the detected value of the suction pressure detecting means. In addition to the effect of the invention according to any one of claims 1 to 5, a dryer is sufficient. It is possible to detect the circulation composition of non-azeotropic refrigerant while absorbing moisture, achieve these two objectives with a single bypass, simplify the refrigerant circuit, and achieve miniaturization and high reliability. The effect of being able to A.

  According to Claim 7 of this invention, in the invention in any one of Claims 1-6, since the attachment attitude | position of the dryer was made downward with respect to the flow direction, it is in any one of Claims 1-6 In addition to the effects of the invention, there is an effect that liquid refrigerant or refrigerating machine oil that has flowed into the dryer quickly flows out of the dryer and can quickly enter a stable operation.

Embodiment 1 FIG.
A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a refrigerant circuit diagram of the air-conditioning apparatus according to the first embodiment. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as the conventional example shown in FIG.

  15 is a bypass circuit that branches from between the second expansion device 6 and the liquid side connection refrigerant pipe 9, and the other end is connected to the refrigerant pipe between the switching valve 2 and the compressor 1, and 16 is a bypass circuit 15. A dryer provided in the middle of the piping, 17 is a bypass throttle device (hereinafter referred to as a third throttle device) provided downstream of the dryer 16 in the middle of the bypass circuit 15, and 18a is a third throttle device 17 of the bypass circuit 15. A first bypass heat exchanger in which heat is exchanged between a portion further downstream and a portion between the second expansion device 6 and the heat source device side heat exchanger 3, and 18 b is a third expansion device 17 of the bypass circuit 15. A second bypass heat exchanger 19 for exchanging heat between the downstream portion and the portion between the second expansion device 6 and the liquid-side connecting refrigerant pipe 9 is provided by the expansion device 17 in the middle of the bypass circuit 15. 1st temperature provided in the upstream part Outlet means 20 is a second temperature detecting means 21 provided downstream of the expansion device 17 in the pipeline of the bypass circuit 15 and upstream of the first and second bypass heat exchangers 18a and 18b. This is suction pressure detection means provided in a portion between the valve 2 and the compressor 1.

  Next, the flow of the refrigerant will be described with reference to the drawings. First, at the time of cooling, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 flows into the heat source machine side heat exchanger 3 through the switching valve 2, and is condensed by exchanging heat with air and the like. Becomes a refrigerant. Furthermore, the second expansion device 6 that is fully open during cooling and the liquid side connection refrigerant pipe 9 are passed through to reach the indoor units B, C, and D, and the degree of superheat at the outlets of the indoor unit side heat exchangers 7b, 7c, and 7d is increased. The first throttling devices 8b, 8c, and 8d controlled so as to be within a certain range are throttling to a low-pressure gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant flows into the indoor unit side heat exchangers 7b, 7c, and 7d, exchanges heat with indoor air and gasifies, and forms the gas side connection refrigerant pipe 10, the switching valve 2, and the accumulator 4. It returns to the compressor 1 through this. The refrigerating machine oil inside the accumulator 4 returns to the compressor 1 through the oil return hole 5 together with the liquid refrigerant.

  Further, a part of the liquid refrigerant that has passed through the second expansion device 6 in the fully opened state flows into the bypass circuit 15 from the heat source device side heat exchanger 3. In the bypass circuit 15, after passing through the dryer 16, the pressure is reduced to a low pressure by the third expansion device 17 to become a low-temperature low-pressure gas-liquid two-phase refrigerant. This low-temperature and low-pressure gas-liquid two-phase refrigerant is a high-temperature and high-pressure liquid refrigerant exiting the heat source unit side heat exchanger 3 and a high-temperature and high-pressure refrigerant exiting the second expansion device 6 in the bypass heat exchangers 18a and 18b. It exchanges heat with the liquid refrigerant, gasifies, joins the refrigerant that has passed through the indoor units B, C, and D between the switching valve 2 and the compressor 1, and returns to the compressor 1. On the other hand, the liquid refrigerant that has exited the heat source apparatus side heat exchanger 3 is cooled by the first bypass heat exchanger 18a, and the liquid refrigerant that flows into the bypass circuit 15 has a temperature higher than that of the liquid refrigerant that has exited the heat source apparatus side heat exchanger 3. Decreases. The refrigerant further passes through the second expansion device 6 and is cooled by the second bypass heat exchanger 18b, and the liquid refrigerant flowing into the liquid side connection refrigerant pipe 9 is sufficiently subcooled. Therefore, even if the liquid side connection refrigerant pipe 9 is long and the pressure drop of the refrigerant is large while flowing therethrough, the indoor units B, C, and D are installed above the heat source unit A and the liquid side connection refrigerant. Even if the influence of the gravity of the liquid refrigerant in the pipe is great, the refrigerant flowing into the first expansion devices 8a, 8b, 8c can secure a liquid state and can be stably operated.

  At the time of heating, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 reaches the indoor units B, C, D through the switching valve 2 and the gas side connection refrigerant pipe 10, and the indoor unit side heat exchangers 7b, 7c. , 7d, and heat exchange with indoor air to condense and become a high-temperature and high-pressure liquid refrigerant. The liquid refrigerant that has exited the indoor heat exchangers 7b, 7c, and 7d is slightly decompressed by the first expansion devices 7b, 7c, and 7d that are almost fully open during heating, and the second expansion is made through the liquid-side connection refrigerant pipe 9. The device 6 is reached, where it is throttled to a low-pressure gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant flows into the heat source machine side heat exchanger 3, exchanges heat with air and the like, and gasifies, and returns to the compressor 1 through the switching valve 2 and the accumulator 4. The refrigerating machine oil inside the accumulator 4 returns to the compressor 1 through the oil return hole 5 together with the liquid refrigerant.

  Further, part of the liquid refrigerant that has passed through the first expansion devices 8a, 8b, 8c and the liquid-side connection refrigerant pipe 9 in the fully opened state flows into the bypass circuit 15 from the indoor unit-side heat exchangers 7b, 7c, 7d. In the bypass circuit 15, after passing through the dryer 16, the pressure is reduced to a low pressure by the third expansion device 17 to become a low-temperature low-pressure gas-liquid two-phase refrigerant. The low-temperature and low-pressure gas-liquid two-phase refrigerant includes a high-temperature and high-pressure liquid refrigerant that has exited the liquid-side connection refrigerant pipe 9 in the bypass heat exchanger 18b, and a low-pressure that has been squeezed by the second expansion device 6 in the bypass heat exchanger 18a. The gas-liquid two-phase refrigerant is heat exchanged, gasified, and merged with the refrigerant that has passed through the heat source unit side heat exchanger 3 between the switching valve 2 and the compressor 1, and returns to the compressor 1. On the other hand, the liquid refrigerant exiting the liquid side connection refrigerant pipe 9 is cooled by the second bypass heat exchanger 18b, and the temperature of the liquid refrigerant flowing into the bypass circuit 15 is lower than that of the liquid refrigerant exiting the liquid side connection refrigerant pipe 9. And the refrigerant | coolant which flows in into the 2nd expansion device 6 can ensure a liquid state, and the stable driving | operation is possible.

  Next, the operation of the dryer 16 will be described. The moisture contained in the refrigerant / refrigeration oil discharged from the compressor 1 does not change until reaching the starting point of the bypass circuit 15 as long as it is below the saturation upper limit. From this point, in the main refrigerant circuit leading to the junction with the bypass circuit 15 through the switching valve 2 via the indoor heat exchangers 7b, 7c, and 7d during cooling and through the heat source unit heat exchanger 3 during heating. Thereafter, the moisture contained in the refrigerant / refrigerant oil does not change. On the other hand, in the bypass circuit 15, when the refrigerant / refrigerant oil flows into the dryer 16, the moisture is absorbed there, and the moisture content in the refrigerant / refrigerant oil decreases downstream of the dryer 16. The refrigerant / refrigerant oil flowing through the bypass circuit 15 between the switching valve 2 and the compressor 1 and the refrigerant / refrigerant oil flowing through the main refrigerant circuit are merged. The moisture contained in the refrigerant / refrigerant oil flowing through the bypass circuit 15 is mixed with the moisture contained in the refrigerant / refrigerant oil flowing through the main refrigerant circuit, and the combined moisture is greater than the amount of water contained in the refrigerant / refrigerant oil flowing through the main refrigerant circuit. The amount decreases at that concentration. That is, moisture is absorbed by the dryer 16 in the bypass circuit 15 and the moisture content in the refrigerant circuit is reduced.

  In this embodiment, the moisture adsorption rate is slower than in the case where a dryer is provided in the main refrigerant circuit, but the rate of hydrolysis degradation of the polyester oil is also slow, so the moisture of the dryer 16 in the middle of the bypass circuit 15 piping. Hydrolysis is sufficiently suppressed by the adsorption ability, and sludge component generation in the compressor 1 can be suppressed. Moreover, by providing the dryer 16 in the middle of the piping of the bypass circuit 15, the impact of the refrigerant flow flowing through the dryer 16 can be reduced, and the dryer 16 is less likely to be crushed. Further, since the refrigerant flowing into the dryer 16 is cooled by the first and second bypass heat exchangers 18a and 18b, the refrigerant flows into the dryer 16 even when the compressor 1 is started up or during a transient operation such as defrosting. It is easy to make the refrigerant to be in a liquid state, and the dryer 16 becomes more difficult to pulverize. Further, when the temperature of the refrigerant is low, the water saturation solubility in the refrigerant is low, and in the coexistence with the dryer, moisture is more easily transferred to the dryer than in the refrigerant, and the moisture adsorption capacity of the dryer is increased. Therefore, when the temperature of the refrigerant flowing into the dryer 16 is lowered, the moisture adsorption amount of the dryer 16 is increased accordingly, and hydrolysis of the refrigerating machine oil can be suppressed.

Embodiment 2. FIG.
A second embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a refrigerant circuit diagram of the air-conditioning apparatus according to the second embodiment. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as the conventional example shown in FIG.

  15 is a bypass circuit that branches from between the second expansion device 6 and the liquid side connection refrigerant pipe 9, and the other end is connected to the refrigerant pipe between the switching valve 2 and the compressor 1, and 16 is a bypass circuit 15. A dryer provided in the middle of the piping, 17 is a third throttle device provided downstream of the dryer 16 in the middle of the bypass circuit 15, and 18 is a portion upstream of the dryer 16 of the bypass circuit 15, the switching valve 2 and the accumulator. The bypass heat exchanger for exchanging heat with the portion between the heat exchanger 4 and the first temperature detecting means 19 provided in the upstream portion of the expansion device 17 in the middle of the piping of the bypass circuit 15, and 20 of the bypass circuit 15 Second temperature detection means 21 provided downstream of the expansion device 17 in the middle of the pipe, 21 is suction pressure detection means provided in a portion between the switching valve 2 and the compressor 1.

  Next, the flow of the refrigerant will be described with reference to the drawings. A main refrigerant comprising the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the second expansion device 6, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d. Since the refrigerant flow during cooling and heating of the circuit is exactly the same as in the first embodiment, the description thereof will be omitted, and the refrigerant flow in the bypass circuit 15 will be described.

  The first expansion devices 8a, 8b, and 8c that are fully opened from the indoor unit side heat exchangers 7b, 7c, and 7d when passing through the fully expanded second expansion device 6 from the heat source device side heat exchanger 3 during cooling. Then, a part of the liquid refrigerant that has passed through the liquid side connection refrigerant pipe 9 flows into the bypass circuit 15. The liquid refrigerant that has flowed into the bypass circuit 15 undergoes heat exchange with the low-temperature and low-pressure refrigerant that has passed through the switching valve 2 in the bypass heat exchanger 18, and the temperature is lowered. After passing through the dryer 16, the pressure is reduced to a low pressure by the third expansion device 17. It becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant. The low-temperature and low-pressure gas-liquid two-phase refrigerant merges with the refrigerant in the main refrigerant circuit that has passed through the switching valve 2 between the switching valve 2 and the accumulator 4, and is separated into gas and liquid by the accumulator 4 and returns to the compressor 1.

  Next, the operation of the dryer 16 will be described. The moisture contained in the refrigerant / refrigeration oil discharged from the compressor 1 does not change until reaching the starting point of the bypass circuit 15 as long as it is below the saturation upper limit. From this point, in the main refrigerant circuit leading to the junction with the bypass circuit 15 through the switching valve 2 via the indoor heat exchangers 7b, 7c, and 7d during cooling and through the heat source unit heat exchanger 3 during heating. Thereafter, the moisture contained in the refrigerant / refrigerant oil does not change. On the other hand, in the bypass circuit 15, when the refrigerant / refrigerant oil flows into the dryer 16, the moisture is absorbed there, and the moisture content in the refrigerant / refrigerant oil decreases downstream of the dryer 16. The refrigerant / refrigerant oil flowing through the bypass circuit 15 between the switching valve 2 and the compressor 1 and the refrigerant / refrigerant oil flowing through the main refrigerant circuit are merged. The moisture contained in the refrigerant / refrigerant oil flowing through the bypass circuit 15 is mixed with the moisture contained in the refrigerant / refrigerant oil flowing through the main refrigerant circuit, and the combined moisture is greater than the amount of water contained in the refrigerant / refrigerant oil flowing through the main refrigerant circuit. The amount decreases at that concentration. That is, moisture is absorbed by the dryer 16 in the bypass circuit 15 and the moisture content in the refrigerant circuit is reduced.

  Even in this embodiment, the moisture adsorption rate is slower than the case where a dryer is provided in the main refrigerant circuit, but the rate of hydrolysis degradation of the polyester oil is also slow, so the moisture of the dryer 16 in the middle of the bypass circuit 15 piping. Hydrolysis is sufficiently suppressed by the adsorption ability, and sludge component generation in the compressor 1 can be suppressed. Moreover, by providing the dryer 16 in the middle of the piping of the bypass circuit 15, the impact of the refrigerant flow flowing through the dryer 16 can be reduced, and the dryer 16 is less likely to be crushed. Furthermore, since the refrigerant flowing into the dryer 16 is cooled by the bypass heat exchanger 18, the refrigerant flowing into the dryer 16 can be easily put into a liquid state even when the compressor 1 is started or during a transient operation such as defrosting. The dryer 16 becomes more difficult to grind. Further, when the temperature of the refrigerant is low, the water saturation solubility in the refrigerant is low, and in the coexistence with the dryer, moisture is more easily transferred to the dryer than in the refrigerant, and the moisture adsorption capacity of the dryer is increased. Therefore, when the temperature of the refrigerant flowing into the dryer 16 is lowered, the moisture adsorption amount of the dryer 16 is increased accordingly, and hydrolysis of the refrigerating machine oil can be suppressed.

Embodiment 3 FIG.
A third embodiment of the present invention will be described below with reference to FIG. FIG. 3 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 3. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as the conventional example shown in FIG.

  15 is a bypass circuit that branches from between the second expansion device 6 and the liquid side connection refrigerant pipe 9, and the other end is connected to the refrigerant pipe between the switching valve 2 and the compressor 1, and 16 is a bypass circuit 15. A dryer provided in the middle of the piping, 17 is a third expansion device provided downstream of the dryer 16 in the middle of the bypass circuit 15, and 18 is a heat source side heat exchange with a portion of the bypass circuit 15 upstream of the dryer 16. A bypass heat exchanger for exchanging heat with a part of the air flowing into the lowermost portion of the cooler 3, 19 is a first temperature detection means provided in a portion upstream of the expansion device 17 in the middle of the piping of the bypass circuit 15. , 20 is a second temperature detecting means provided downstream of the expansion device 17 in the middle of the bypass circuit 15, and 21 is a suction pressure detecting means provided in a portion between the switching valve 2 and the compressor 1. .

  Next, the flow of the refrigerant will be described with reference to the drawings. A main refrigerant comprising the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the second expansion device 6, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d. Since the refrigerant flow during cooling and heating of the circuit is exactly the same as in the first embodiment, the description thereof will be omitted, and the refrigerant flow in the bypass circuit 15 will be described.

  The first expansion devices 8a, 8b, and 8c that are fully opened from the indoor unit side heat exchangers 7b, 7c, and 7d when passing through the fully expanded second expansion device 6 from the heat source device side heat exchanger 3 during cooling. Then, a part of the liquid refrigerant that has passed through the liquid side connection refrigerant pipe 9 flows into the bypass circuit 15. The liquid refrigerant flowing into the bypass circuit 15 exchanges heat with a part of the air flowing into the lowermost part of the heat source unit side heat exchanger 3 by the bypass heat exchanger 18, and the temperature is lowered. The pressure reducing device 17 reduces the pressure to a low pressure and becomes a low-temperature low-pressure gas-liquid two-phase refrigerant. The low-temperature and low-pressure gas-liquid two-phase refrigerant merges with the refrigerant in the main refrigerant circuit that has passed through the switching valve 2 between the switching valve 2 and the accumulator 4, and is separated into gas and liquid by the accumulator 4 and returns to the compressor 1. In addition, in the lowest part of the heat source apparatus side heat exchanger 3 provided with the bypass heat exchanger 18 that becomes an evaporator at the time of heating, it is difficult for wind to pass through the drain flow from the upper part, and frost is generated and is likely to grow. It is warmed by the bypass heat exchanger 18 and hardly forms frost.

  Also in the third embodiment, a dryer 16 that absorbs moisture is provided in the bypass circuit 15, and the refrigerant flowing into the dryer 16 is cooled by the bypass heat exchanger 18, so that the refrigerant circuit is the same as in the first and second embodiments. The moisture content therein decreases, hydrolysis of the refrigerating machine oil can be suppressed, and pulverization of the dryer 16 by the refrigerant flow can be prevented.

Embodiment 4 FIG.
A fourth embodiment of the present invention will be described below with reference to FIG. FIG. 4 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 4. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as the conventional example shown in FIG.

  Reference numeral 15 denotes a bypass circuit that branches from between the discharge portion of the compressor 1 and the switching valve 2, and the other end is connected to a refrigerant pipe between the switching valve 2 and the compressor 1. The provided dryer, 17 is a third throttle device provided downstream of the dryer 16 in the middle of the bypass circuit 15, and 18 is a portion of the bypass circuit 15 upstream of the dryer 16 and the third throttle of the bypass circuit 15. A bypass heat exchanger that exchanges heat with a portion downstream from the device 17, 19 is a first temperature detection means provided in a portion upstream of the expansion device 17 in the middle of the piping of the bypass circuit 15, and 20 is a piping of the bypass circuit 15. A second temperature detecting means 21 provided downstream from the throttle device 17 on the way, 21 is a second pressure detecting means provided in a portion between the switching valve 2 and the compressor 1.

  Next, the flow of the refrigerant will be described with reference to the drawings. A main refrigerant comprising the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the second expansion device 6, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d. Since the refrigerant flow during cooling and heating of the circuit is exactly the same as in the first embodiment, the description thereof will be omitted, and the refrigerant flow in the bypass circuit 15 will be described.

  In both cases of cooling and heating, part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the bypass circuit 15. The high-temperature and high-pressure gas refrigerant flowing into the bypass circuit 15 exchanges heat with the low-pressure refrigerant on the downstream side in the bypass heat exchanger 18 to lower the temperature and liquefy, and after passing through the dryer 16, the third expansion device 17. Then, the pressure is reduced to a low pressure to become a low-temperature low-pressure gas-liquid two-phase refrigerant, and the bypass heat exchanger 18 exchanges heat with the high-pressure side refrigerant for gasification. This low-temperature and low-pressure gas refrigerant merges with the refrigerant in the main refrigerant circuit that has passed through the switching valve 2 between the switching valve 2 and the accumulator 4, and is separated into gas and liquid by the accumulator 4 and returns to the compressor 1.

  Also in the fourth embodiment, a dryer 16 that absorbs moisture is provided in the bypass circuit 15, and the refrigerant flowing into the dryer 16 is cooled by the bypass heat exchanger 18. Therefore, as in the first, second, and third embodiments. The moisture content in the refrigerant circuit decreases, hydrolysis of the refrigerating machine oil can be suppressed, and the dryer 16 can be prevented from being crushed by the refrigerant flow. In the fourth embodiment, since the cycle from the compressor 1 through the bypass circuit 15 to the compressor 1 is very short, the response time is good, and the time during which the liquid is not supplied to the dryer is in a transient state. It is very short and the dryer 16 is difficult to grind. Further, since this cycle does not include the liquid-side connecting refrigerant pipe 9 and the gas-side connecting refrigerant pipe 10, oxidation that occurs when sufficient non-oxidative brazing is not performed when the pipes 9 and 10 are constructed. The scale does not flow into the dryer 16 in the bypass circuit 15, thereby eliminating the danger of blocking the flow path and crushing the dryer.

Embodiment 5 FIG.
The fifth embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 5. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as the conventional example shown in FIG.

  15 is a bypass circuit that branches from between the compressor 1 and the switching valve 2, and the other end is connected to the refrigerant pipe between the switching valve 2 and the compressor 1, and 16 is provided in the middle of the bypass circuit 15. A dryer 17 is a third expansion device provided downstream of the dryer 16 in the middle of the bypass circuit 15, and 18 is a portion of the bypass circuit 15 upstream of the dryer 16 and the lowest part of the heat source unit side heat exchanger 3. A bypass heat exchanger that exchanges heat with a part of the air flowing into the part, 19 is a first temperature detecting means provided in a part upstream of the expansion device 17 in the middle of the bypass circuit 15, and 20 is a bypass circuit 15 Reference numeral 21 denotes a second temperature detection means provided downstream from the expansion device 17 in the middle of the pipe, and reference numeral 21 denotes a second pressure detection means provided in a portion between the switching valve 2 and the compressor 1.

  Next, the flow of the refrigerant will be described with reference to the drawings. A main refrigerant comprising the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the second expansion device 6, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d. Since the refrigerant flow during cooling and heating of the circuit is exactly the same as in the first embodiment, the description thereof will be omitted, and the refrigerant flow in the bypass circuit 15 will be described.

  In both cases of cooling and heating, part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the bypass circuit 15. The high-temperature and high-pressure gas refrigerant that has flowed into the bypass circuit 15 exchanges heat with a part of the air that flows into the lowermost part of the heat source unit side heat exchanger 3 in the bypass heat exchanger 18 to lower the temperature and liquefy. After passing through the dryer 16, the pressure is reduced to a low pressure by the third throttling device 17, and the refrigerant in the main refrigerant circuit that has passed through the switching valve 2 is joined between the switching valve 2 and the accumulator 4, and is separated by gas-liquid separation and compressed by the accumulator 4. Return to Machine 1. In the fifth embodiment, similarly to the third embodiment, the flow of drain from the upper part in the lowermost part of the heat source unit side heat exchanger 3 provided with the bypass heat exchanger 18 that becomes an evaporator during heating is provided. However, it is difficult for the wind to pass through and frost is generated and is likely to grow, but it is warmed by the bypass heat exchanger 18 and is difficult to frost.

  Also in the fifth embodiment, a dryer 16 that absorbs moisture is provided in the bypass circuit 15, and the refrigerant flowing into the dryer 16 is cooled by the bypass heat exchanger 18, so that the refrigerant circuit is the same as in the first to fourth embodiments. The moisture content therein decreases, hydrolysis of the refrigerating machine oil can be suppressed, and pulverization of the dryer 16 by the refrigerant flow can be prevented. Further, as in the fourth embodiment, since the cycle from the compressor 1 through the bypass circuit 15 to the compressor 1 is very short, the response time is good, and the transition time in which no liquid is supplied to the dryer is reached. It is very short and the dryer 16 is difficult to grind. Further, since this cycle does not include the liquid-side connecting refrigerant pipe 9 and the gas-side connecting refrigerant pipe 10, oxidation that occurs when sufficient non-oxidative brazing is not performed when the pipes 9 and 10 are constructed. The scale does not flow into the dryer 16 in the bypass circuit 15, thereby eliminating the danger of blocking the flow path and crushing the dryer.

Embodiment 6 FIG.
A sixth embodiment of the present invention will be described below with reference to FIG. FIG. 6 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 6. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as the conventional example shown in FIG.

  15 is a bypass circuit that branches from between the compressor 1 and the switching valve 2, and the other end is connected to the refrigerant pipe between the switching valve 2 and the compressor 1, and 16 is provided in the middle of the bypass circuit 15. A dryer 17 is a third expansion device provided downstream of the dryer 16 in the middle of the bypass circuit 15, and 18 a is a portion upstream of the dryer 16 of the bypass circuit 15 and the lowest part of the heat source unit side heat exchanger 3. A first bypass heat exchanger 18b that exchanges heat with a part of the air flowing into the part, a part between the first bypass heat exchanger 18a of the bypass circuit 15 and the dryer 16, and a third throttle A second bypass heat exchanger that exchanges heat with a portion downstream from the device 17, 19 is a first temperature detection means provided at a portion upstream of the expansion device 17 in the middle of the piping of the bypass circuit 15, and 20 is a bypass circuit. 15 pipes in the middle Second temperature detecting means provided from the downstream expansion device 17, 21 is a second pressure detecting means provided in the portion between the switching valve 2 and the compressor 1.

  Next, the flow of the refrigerant will be described with reference to the drawings. A main refrigerant comprising the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the second expansion device 6, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d. Since the refrigerant flow during cooling and heating of the circuit is exactly the same as in the first embodiment, the description thereof will be omitted, and the refrigerant flow in the bypass circuit 15 will be described.

  In both cases of cooling and heating, part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the bypass circuit 15. The high-temperature and high-pressure gas refrigerant that has flowed into the bypass circuit 15 exchanges heat with a part of the air that flows into the lowermost part of the heat source unit side heat exchanger 3 in the first bypass heat exchanger 18a, and the temperature decreases. The refrigerant is liquefied and exchanges heat with the downstream low-pressure side refrigerant in the second bypass heat exchanger 18b to further reduce the temperature of the refrigerant. Thereafter, after passing through the dryer 16, the pressure is reduced to a low pressure by the third expansion device 17 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant, and heat is exchanged with the high-pressure side refrigerant in the bypass heat exchanger 18. It merges with the refrigerant of the main refrigerant circuit that has passed through the switching valve 2 with the accumulator 4, and is separated into gas and liquid by the accumulator 4 and returns to the compressor 1. In the sixth embodiment, as in the third embodiment, in the lowermost part of the heat source unit side heat exchanger 3 provided with the first bypass heat exchanger 18a, which is an evaporator during heating, from the top. Although the wind does not easily pass through the drain flow and frost is generated and is likely to grow, it is heated by the bypass heat exchanger 18 and is difficult to frost.

  Also in the sixth embodiment, a dryer 16 that absorbs moisture is provided in the bypass circuit 15, and the refrigerant flowing into the dryer 16 is cooled by the bypass heat exchangers 18a and 18b. Therefore, as in the first to fifth embodiments. The moisture content in the refrigerant circuit decreases, hydrolysis of the refrigerating machine oil can be suppressed, and the dryer 16 can be prevented from being crushed by the refrigerant flow. Further, as in the fourth and fifth embodiments, the cycle from the compressor 1 through the bypass circuit 15 to the compressor 1 is very short, so that the response is good and the liquid is not supplied to the dryer. The time is very short and the dryer 16 is difficult to grind. Further, since this cycle does not include the liquid-side connecting refrigerant pipe 9 and the gas-side connecting refrigerant pipe 10, oxidation that occurs when sufficient non-oxidative brazing is not performed when the pipes 9 and 10 are constructed. The scale does not flow into the dryer 16 in the bypass circuit 15, thereby eliminating the danger of blocking the flow path and crushing the dryer.

Embodiment 7 FIG.
A seventh embodiment of the present invention will be described below with reference to FIGS. 1 is a refrigerant circuit diagram of an air-conditioning apparatus according to Embodiment 7, FIG. 7 is a block diagram relating to composition calculation of the air-conditioning apparatus according to Embodiment 7, and FIG. 8 shows the operation of the composition calculation means. It is a flow chart. Although FIG. 2 to FIG. 6 are different in the position, configuration, and refrigerant flow of the bypass circuit 15, the seventh embodiment is applied as in FIG. Further, a hydrofluorocarbon mixed refrigerant is used as the working medium in this embodiment.

  In the figure, reference numeral 19 denotes a first temperature detecting means which is provided in a portion upstream of the expansion device 17 in the middle of the bypass circuit 15 and detects the temperature of the high-temperature and high-pressure liquid refrigerant at the inlet of the third expansion device 17. Is provided downstream of the expansion device 17 in the middle of the bypass circuit 15 and upstream of the first and second bypass heat exchangers 18a and 18b, and is a low-temperature and low-pressure gas-liquid at the outlet of the third expansion device 17. Second temperature detecting means for detecting the temperature of the two-phase refrigerant, 21 is second pressure detecting means provided in a portion between the switching valve 2 and the compressor 1, and 22 is first temperature detecting means 19. The composition calculation means calculates the composition of the mixed refrigerant based on the detection values of the second temperature detection means 20 and the second pressure detection means 21.

  Next, the composition calculation operation will be described with reference to FIG. First, in step 100, the composition Xi is assumed for each component of the mixed refrigerant. In step 101, the detected values T1, T2, and P2 are detected from the first temperature detecting means 19, the second temperature detecting means 20, and the suction pressure detecting means 21, respectively. In step 102, a high-pressure liquid enthalpy H1 is calculated from the circulation composition Xi assumed in step 100 and the detected value T1 of the first temperature detecting means 19. In step 103, a low-pressure two-phase enthalpy H2 is calculated from the circulation composition Xi, the detection value T2 of the second temperature detection means 20 and the detection value P2 of the suction pressure detection means 21. In step 104, the above H1 and H2 are compared, and the circulation composition assumption is repeated until they are equal. As a result, the value of Xi when H1 and H2 become equal is calculated as the circulation composition. Here, the subscript i indicates that the refrigerant is a mixture of i components.

Embodiment 8 FIG.
The eighth embodiment of the present invention will be described below with reference to FIG. FIG. 9 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 8. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, and the above is shown in FIG. This is similar to the conventional example shown. An oil separator 23 is provided between the discharge portion of the compressor 1 and the switching valve 2 and separates the refrigeration oil discharged from the compressor 1 together with the refrigerant from the gas refrigerant, and 24 is switched to the bottom portion of the oil separator 23. An oil return bypass circuit connecting the valve 2 and the suction part of the compressor 1 and returning the separated refrigeration oil to the suction part of the compressor 1, and 25 is a fourth part provided in the middle of the piping of the oil return bypass circuit 24. It is an aperture device.

  Next, the flow of the refrigerant will be described with reference to the drawings. First, at the time of cooling, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 flows into the heat source machine side heat exchanger 3 through the switching valve 2, and is condensed by exchanging heat with air and the like. Becomes a refrigerant. Furthermore, the liquid side connecting refrigerant pipe 9 is passed through to the indoor units B, C, D, and the first control is performed so that the degree of superheat at the outlets of the indoor unit side heat exchangers 7b, 7c, 7d is within a certain range. The throttling devices 8b, 8c, and 8d are throttled to a low-pressure gas-liquid two-phase state. The low-pressure gas-liquid two-phase refrigerant flows into the indoor unit side heat exchangers 7b, 7c, and 7d, exchanges heat with indoor air and gasifies, and forms the gas side connection refrigerant pipe 10, the switching valve 2, and the accumulator 4. It returns to the compressor 1 through this. The refrigerating machine oil inside the accumulator 4 returns to the compressor 1 through the oil return hole 5 together with the liquid refrigerant.

  At the time of heating, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 reaches the indoor units B, C, D through the switching valve 2 and the gas side connection refrigerant pipe 10, and the indoor unit side heat exchangers 7b, 7c. , 7d, and heat exchange with indoor air to condense and become a high-temperature and high-pressure liquid refrigerant. The liquid refrigerant that has exited the indoor heat exchangers 7b, 7c, and 7d is throttled to the low-pressure gas-liquid two-phase state by the first expansion devices 8b, 8c, and 8d, and the low-pressure gas-liquid two-phase refrigerant is connected to the liquid side. It flows into the heat source machine side heat exchanger 3 through the refrigerant pipe 9, exchanges heat with air and gasifies, and returns to the compressor 1 through the switching valve 2 and the accumulator 4. The refrigerating machine oil inside the accumulator 4 returns to the compressor 1 through the oil return hole 5 together with the liquid refrigerant.

  In both cases of cooling and heating, the low-temperature and low-pressure gas refrigerant sucked into the compressor 1 is compressed to become high-temperature and high-pressure gas refrigerant and discharged from the compressor 1. At this time, a part of the refrigerating machine oil inside the compressor 1 is also discharged and flows into the oil separator 23 together with the gas refrigerant, where it is separated from the gas refrigerant. The gas refrigerant separated by the oil separator 23 flows to the switching valve 2, and the refrigerating machine oil flows into the oil return bypass circuit 24. The refrigerating machine oil that has flowed into the oil return bypass circuit 24 is decompressed to a low pressure by the fourth expansion device 25, and joins the refrigerant in the main refrigerant circuit that has passed through the switching valve 2 between the switching valve 2 and the accumulator 4. Since the refrigerating machine oil is separated at the discharge part of the compressor 1 in this way, the circulation flow rate ratio of the refrigerating machine oil in the main refrigerant circuit is very low, and the first expansion device 8b in the indoor units B, C, D, The flow rate of the refrigerating machine oil flowing through 8c and 8d is significantly reduced.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 exists as a solid in a refrigerating machine oil, or melt | dissolves and exists. When the refrigerant is discharged from the compressor 1, it is mixed with the refrigerating machine oil and discharged into the discharge gas, but is separated by the oil separator 23 and does not flow into the main refrigerant circuit, so the indoor units B, C, D The flow rate of the refrigerating machine oil flowing through the first throttling devices 8b, 8c, and 8d inside is remarkably reduced, and the integrated flow rate of the deteriorated refrigerating machine oil circulating with the refrigerating machine oil is also reduced. As a result, the amount of the refrigeration oil deteriorated material that becomes sludge and adheres to the first expansion devices 8b, 8c, 8d can be reduced, and a shortage of the flow of the first expansion devices 8b, 8c, 8d can be avoided. There is no shortage of capability, and reliability is significantly improved.

Embodiment 9 FIG.
A ninth embodiment of the present invention will be described below with reference to FIG. FIG. 10 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 9. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes, 7b, 7c, 7d are indoor unit side heat exchangers, 8b, 8c, 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, 23 is an oil separator, Reference numeral 24 denotes an oil return bypass circuit, and reference numeral 25 denotes a fourth throttling device. The above is the same as in the eighth embodiment shown in FIG. 26 is a sludge filter provided in the upstream part of the 4th expansion device 25 in the middle of piping of the oil return bypass circuit 24.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d Since the refrigerant flow and the operation of the oil separator 23 are exactly the same as those in the eighth embodiment, the description thereof will be omitted, and the flow of the refrigerating machine oil in the oil return bypass circuit 24 will be described. The refrigerating machine oil separated by the oil separator 23 flows into the oil return bypass circuit 24, passes through the sludge filter 26, is reduced to a low pressure by the fourth expansion device 25, and is switched between the switching valve 2 and the accumulator 4. It merges with the refrigerant in the main refrigerant circuit that has passed through the valve 2.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with refrigerating machine oil, is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and the oil return bypass circuit 24 In the sludge filter 26. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 decreases, and the amount of sludge that adheres to the oil return hole 5 decreases. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 10 FIG.
The tenth embodiment of the present invention will be described below with reference to FIG. FIG. 11 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 10. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes, 7b, 7c, 7d are indoor unit side heat exchangers, 8b, 8c, 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, 23 is an oil separator, 24 is an oil return bypass circuit, 25 is a fourth throttling device, 26 is a sludge filter, and the above is the same as in the ninth embodiment shown in FIG. A bypass heat exchanger 27 exchanges heat between a portion upstream of the sludge filter 26 of the oil return bypass circuit 24 and a part of the air flowing into the lowermost portion of the heat source unit side heat exchanger 3.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d Since the refrigerant flow and the operation of the oil separator 23 are exactly the same as those in the eighth embodiment, the description thereof will be omitted, and the flow of the refrigerating machine oil in the oil return bypass circuit 24 will be described. The refrigerating machine oil separated by the oil separator 23 flows into the oil return bypass circuit 24, and heat is exchanged with a part of the air flowing into the lowermost part of the heat source unit side heat exchanger 3 by the bypass heat exchanger 27, so that the temperature is increased. Then, the pressure is reduced to a low pressure by the fourth throttling device 25 through the sludge filter 26 and joins the refrigerant in the main refrigerant circuit passing through the switching valve 2 between the switching valve 2 and the accumulator 4. In the tenth embodiment, as in the third, fifth and sixth embodiments, in the lowermost part of the heat source unit side heat exchanger 3 provided with the bypass heat exchanger 18 which becomes an evaporator during heating, from the top. However, it is difficult for the wind to pass through the drain flow and frost is generated and grows easily, but it is warmed by the bypass heat exchanger 18 and is difficult to frost.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with refrigerating machine oil, is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and the oil return bypass circuit 24 In the sludge filter 26. Moreover, by passing through the bypass heat exchanger 27, the temperature of the refrigerating machine oil decreases, and the concentration of the refrigerant in the refrigerating machine oil increases. Thereby, the refrigerating machine oil degradation product which melted in refrigerating machine oil precipitates, and what was originally melted in refrigerating machine oil can also be caught in sludge filter 26. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 is further reduced, and the amount of sludge adhering to the oil return hole 5 is reduced. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 11 FIG.
The eleventh embodiment of the present invention will be described below with reference to FIG. FIG. 12 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 11. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes, 7b, 7c, 7d are indoor unit side heat exchangers, 8b, 8c, 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, 23 is an oil separator, 24 is an oil return bypass circuit, 25 is a fourth throttling device, 26 is a sludge filter, and the above is the same as in the ninth embodiment shown in FIG. A bypass heat exchanger 27 exchanges heat between a portion upstream of the sludge filter 26 of the oil return bypass circuit 24 and a portion between the switching valve 2 and the accumulator 4.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d Since the refrigerant flow and the operation of the oil separator 23 are exactly the same as those in the eighth embodiment, the description thereof will be omitted, and the flow of the refrigerating machine oil in the oil return bypass circuit 24 will be described. The refrigerating machine oil separated in the oil separator 23 flows into the oil return bypass circuit 24, and in the bypass heat exchanger 27, heat is exchanged with the low-temperature and low-pressure refrigerant that returns to the compressor 1 through the switching valve 2, and the temperature decreases. Through the sludge filter 26, the pressure is reduced to a low pressure by the fourth throttling device 25, and the refrigerant in the main refrigerant circuit passing through the switching valve 2 is joined between the switching valve 2 and the accumulator 4.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with refrigerating machine oil, is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and the oil return bypass circuit 24 In the sludge filter 26. Moreover, by passing through the bypass heat exchanger 27, the temperature of the refrigerating machine oil decreases, and the concentration of the refrigerant in the refrigerating machine oil increases. Thereby, the refrigerating machine oil degradation product which melted in refrigerating machine oil precipitates, and what was originally melted in refrigerating machine oil can also be caught in sludge filter 26. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 is further reduced, and the amount of sludge adhering to the oil return hole 5 is reduced. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 12 FIG.
A twelfth embodiment of the present invention will be described below with reference to FIG. FIG. 13 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 12. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes, 7b, 7c, 7d are indoor unit side heat exchangers, 8b, 8c, 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, 23 is an oil separator, 24 is an oil return bypass circuit, 25 is a fourth throttling device, 26 is a sludge filter, and the above is the same as in the ninth embodiment shown in FIG. 28 is a liquid refrigerant injection circuit that branches from between the oil separator 23 and the switching valve 2 and joins the upstream portion of the sludge filter 26 of the oil return bypass circuit 24, and 29 is a pipe and a heat source side of the liquid refrigerant injection circuit 28. This is a liquid injection circuit heat exchanger that exchanges heat with a part of the air flowing into the lowermost part of the heat exchanger 3.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d The flow of the refrigerant and the operation of the oil separator 23 are the same as those in the eighth embodiment, so the description thereof will be omitted, and the flow of the refrigerant and the refrigerating machine oil in the oil return bypass circuit 24 and the liquid refrigerant injection circuit 28 will be described. A part of the high-temperature and high-pressure gas refrigerant from which the refrigeration oil is separated by the oil separator 23 flows into the liquid refrigerant injection circuit 28, and flows into the lowermost part of the heat source unit side heat exchanger 3 by the liquid injection circuit heat exchanger 29. It exchanges heat with a part of the air to lower the temperature and liquefy, and merges with the refrigeration oil separated by the oil separator 23 and flowing into the oil return bypass circuit 24. The combined liquid refrigerant and refrigeration oil are reduced to a low pressure by the fourth throttling device 25 through the sludge filter 26 and merge with the refrigerant in the main refrigerant circuit passing through the switching valve 2 between the switching valve 2 and the accumulator 4. To do. In the twelfth embodiment, similarly to the third, fifth, sixth and tenth embodiments, at the lowermost part of the heat source unit side heat exchanger 3 provided with the liquid injection circuit heat exchanger 29 which becomes an evaporator during heating. However, it is difficult for the wind to pass through the drain flow from the top and frost is generated and grows easily, but it is warmed by the liquid injection circuit heat exchanger 29 and is difficult to frost.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with a refrigerating machine oil, and is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and is returned to the oil return bypass circuit 24. By flowing in and joining with the liquid refrigerant flowing out of the liquid injection circuit heat exchanger 29 of the liquid refrigerant injection circuit 28, the refrigerant concentration in the refrigerating machine oil is increased and flows into the sludge filter 26 and captured. Thereby, since the refrigerating machine oil degradation product dissolved in refrigerating machine oil precipitates, the sludge filter 26 can also capture what was originally dissolved in the refrigerating machine oil together with sludge present as a solid. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 is further reduced, and the amount of sludge adhering to the oil return hole 5 is reduced. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 13 FIG.
A thirteenth embodiment of the present invention will be described below with reference to FIG. FIG. 14 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 13. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes, 7b, 7c, 7d are indoor unit side heat exchangers, 8b, 8c, 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, 23 is an oil separator, 24 is an oil return bypass circuit, 25 is a fourth throttling device, 26 is a sludge filter, 28 is a liquid refrigerant injection circuit, and the above is the same as in the twelfth embodiment shown in FIG. This is a liquid injection circuit heat exchanger in which heat is exchanged between the piping of the refrigerant injection circuit 28 and the portion between the switching valve 2 and the accumulator 4.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d The flow of the refrigerant and the operation of the oil separator 23 are the same as those in the eighth embodiment, so the description thereof will be omitted, and the flow of the refrigerant and the refrigerating machine oil in the oil return bypass circuit 24 and the liquid refrigerant injection circuit 28 will be described. A part of the high-temperature and high-pressure gas refrigerant from which the refrigeration oil is separated by the oil separator 23 flows into the liquid refrigerant injection circuit 28, and returns to the compressor 1 through the switching valve 2 in the liquid injection circuit heat exchanger 29. It exchanges heat with the refrigerant to lower the temperature and liquefy, and merges with the refrigerating machine oil separated by the oil separator 23 and flowing into the oil return bypass circuit 24. The combined liquid refrigerant and refrigeration oil are reduced to a low pressure by the fourth throttling device 25 through the sludge filter 26 and merge with the refrigerant in the main refrigerant circuit passing through the switching valve 2 between the switching valve 2 and the accumulator 4. To do.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with a refrigerating machine oil, and is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and is returned to the oil return bypass circuit 24. By flowing in and joining with the liquid refrigerant flowing out of the liquid injection circuit heat exchanger 29 of the liquid refrigerant injection circuit 28, the refrigerant concentration in the refrigerating machine oil is increased and flows into the sludge filter 26 and captured. Thereby, since the refrigerating machine oil degradation product which melt | dissolved in refrigerating machine oil precipitates, what was originally melt | dissolved in refrigerating machine oil with the sludge which exists as a solid in the sludge filter 26 can also be capture | acquired. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 is further reduced, and the amount of sludge adhering to the oil return hole 5 is reduced. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 14 FIG.
A fourteenth embodiment of the present invention will be described below with reference to FIG. FIG. 15 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 14. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 The return hole, 6 is the second expansion device, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are the first expansion device, 9 is the liquid side connection refrigerant pipe, and 10 is the gas side connection refrigerant. The piping is the same as that of the first embodiment shown in FIG. 1, 23 is an oil separator, 24 is an oil return bypass circuit, 25 is a fourth throttling device, and 26 is a sludge filter. 28, which is the same as that of the twelfth embodiment shown in FIG. 1, branches from between the second expansion device 6 and the liquid side connection refrigerant pipe 9, and joins the upstream portion of the sludge filter 26 of the oil return bypass circuit 24. This is a liquid refrigerant injection circuit.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. A main refrigerant comprising the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the second expansion device 6, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d. The refrigerant flow during cooling and heating of the circuit is exactly the same as in the first embodiment, and the operation of the oil separator 23 is the same as in the eighth embodiment, so the description thereof is omitted, and the oil return bypass circuit 24 and liquid refrigerant injection are omitted. The flow of the refrigerant and the refrigerating machine oil in the circuit 28 will be described. The refrigerating machine oil separated by the oil separator 23 flows into the oil return bypass circuit 24. Further, during cooling, the liquid refrigerant that has condensed and liquefied through heat exchange with the air in the heat source unit side heat exchanger 3 and passed through the fully-opened second expansion device 6 passes through the indoor unit side heat exchangers 7b and 7c during heating. , 7d, and the liquid refrigerant that has condensed and liquefied by the heat exchange with the first throttling devices 8a, 8b, 8c and the liquid side connection refrigerant pipe 9 in the fully opened state partially flows into the liquid refrigerant injection circuit 28. The refrigerating machine oil that has flowed into the oil return bypass circuit 24 merges. The combined liquid refrigerant and refrigeration oil are reduced to a low pressure by the fourth throttling device 25 through the sludge filter 26 and merge with the refrigerant in the main refrigerant circuit passing through the switching valve 2 between the switching valve 2 and the accumulator 4. To do.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with a refrigerating machine oil, and is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and is returned to the oil return bypass circuit 24. The refrigerant flows in and merges with the liquid refrigerant flowing into the liquid refrigerant injection circuit 28, whereby the refrigerant concentration in the refrigeration oil is increased and flows into the sludge filter 26 and captured. Thereby, since the refrigerating machine oil degradation product which melt | dissolved in refrigerating machine oil precipitates, what was originally melt | dissolved in refrigerating machine oil with the sludge which exists as a solid in the sludge filter 26 can also be capture | acquired. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 is further reduced, and the amount of sludge adhering to the oil return hole 5 is reduced. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 15 FIG.
A fifteenth embodiment of the present invention will be described below with reference to FIG. FIG. 15 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 15. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil of the accumulator 4 Return holes, 7b, 7c, 7d are indoor unit side heat exchangers, 8b, 8c, 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, 23 is an oil separator, 24 is an oil return bypass circuit, 25 is a fourth throttling device, 26 is a sludge filter, and the above is the same as that of the twelfth embodiment shown in FIG. A liquid refrigerant injection circuit 28 branches from between the oil separator 23 and the switching valve 2, and the other end is connected to a refrigerant pipe between the switching valve 2 and the compressor 1, and 30 is in the middle of the liquid refrigerant injection circuit 28. The fifth expansion device 29 is a liquid injection circuit heat exchanger that exchanges heat between the upstream portion and the downstream portion of the fifth expansion device 30 of the liquid refrigerant injection circuit 28. Further, the upstream portion of the sludge filter 26 of the oil return bypass circuit 24 and the upstream portion of the fifth expansion device 30 of the liquid refrigerant injection circuit 28 are connected by piping.

  Next, the flow of refrigerant and refrigerating machine oil will be described with reference to the drawings. During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d The flow of the refrigerant and the operation of the oil separator 23 are the same as those in the eighth embodiment, so the description thereof will be omitted, and the flow of the refrigerant and the refrigerating machine oil in the oil return bypass circuit 24 and the liquid refrigerant injection circuit 28 will be described. A part of the high-temperature and high-pressure gas refrigerant from which the refrigeration oil is separated by the oil separator 23 flows into the liquid refrigerant injection circuit 28, and exchanges heat with the refrigerant on the low-pressure side of the liquid refrigerant injection circuit 28 in the liquid injection circuit heat exchanger 29. The temperature is lowered and liquefied, and a part thereof flows into the fifth expansion device 30 and is depressurized to a low pressure. The liquid injection circuit heat exchanger 29 is heated and gasified by the high-pressure side refrigerant, and the switching valve 2 And the accumulator 4 merge with the refrigerant in the main refrigerant circuit that has passed through the switching valve 2. Further, the remaining refrigerant liquefied on the high pressure side of the liquid injection circuit heat exchanger 29 joins with the refrigeration oil separated by the oil separator 23 and flowing into the oil return bypass circuit 24. The combined liquid refrigerant and refrigeration oil are reduced to a low pressure by the fourth throttling device 25 through the sludge filter 26 and merge with the refrigerant in the main refrigerant circuit passing through the switching valve 2 between the switching valve 2 and the accumulator 4. To do.

  Moreover, the refrigerating machine oil degradation product produced | generated by the sliding part of the compressor 1 is mixed with discharge gas with a refrigerating machine oil, and is discharged in a refrigerant circuit, is isolate | separated with refrigerating machine oil with the oil separator 23, and is returned to the oil return bypass circuit 24. The refrigerant concentration in the refrigerating machine oil is increased to flow into the sludge filter 26 and captured by merging with a part of the liquid refrigerant flowing in from the high pressure side of the liquid injection circuit heat exchanger 29 of the liquid refrigerant injection circuit 28. Is done. Thereby, since the refrigerating machine oil degradation product which melt | dissolved in refrigerating machine oil precipitates, what was originally melt | dissolved in refrigerating machine oil with the sludge which exists as a solid in the sludge filter 26 can also be capture | acquired. Therefore, the content of the refrigeration oil deterioration product in the refrigeration oil that flows into the accumulator 4 and returns to the compressor 1 is further reduced, and the amount of sludge adhering to the oil return hole 5 is reduced. As a result, the refrigerating machine oil in the compressor 1 is not exhausted, and an abnormal high pressure rise / low pressure drop and a discharge gas temperature rise caused thereby can be avoided, and the reliability is remarkably improved. The cycle in which the refrigerant discharged from the compressor 1 returns to the compressor 1 through the oil return bypass circuit 24 does not pass through the liquid side connection refrigerant pipe 9 and the gas side connection refrigerant pipe 10 in the middle. Therefore, the oxidation scale generated when the non-oxidizing brazing is not sufficiently performed during the construction of the liquid side connecting refrigerant pipe 9 and the gas side connecting refrigerant pipe 10 may flow into the sludge filter 26 during operation. There is no danger of blocking the flow path or deforming or destroying the sludge filter.

Embodiment 16 FIG.
FIG. 17 is a longitudinal sectional view showing an embodiment 16 of the dryer 16 used in the first to sixth embodiments. FIG. 17 (a) shows the refrigerant flow direction from left to right. ) Shows the case where the dryer is arranged so that the flow direction of the refrigerant is from bottom to top, and FIG. 7C shows the case where the dryer is arranged so that the flow direction of the refrigerant is from top to bottom. In the figure, 50 is a cylindrical container, 51 is an inflow pipe provided at one end of the container 50, 52 is an outflow pipe provided at the other end of the container 50, 53 is composed mainly of synthetic zeolite, and is made of activated alumina or the like. A dryer core 54, which is blended and hardened with a binder such as an adhesive, is a refrigerating machine oil.

  The refrigerant flowing in from the inflow pipe 51 absorbs the moisture contained in the refrigerant by the dryer core 53. However, since the refrigerant passage passes through the very fine dryer core, the larger one is here. Be captured. Some dryers have a filter provided on the upstream side or downstream side of the dryer core 53, and foreign matter is also captured by the filter portion. Therefore, a dryer having this configuration can be used as the sludge filter 26 in the ninth to fifteenth embodiments. Thus, by using a dryer as the sludge filter 26, moisture can be directly absorbed from the refrigeration oil flowing through the oil return bypass circuit 24, and the sludge filter function and the moisture capturing function can be combined. Thereby, while suppressing hydrolysis of refrigerating machine oil, the refrigerating machine oil degradation product content rate in refrigerating machine oil can also be reduced. As a result, the water content in the main refrigerant circuit and the refrigerating machine oil degradation product content rate are also reduced. The amount of sludge adhering to the expansion devices 8b, 8c, 8d, the oil return hole 5, etc. decreases.

  Moreover, when using the thing of the structure shown in FIG. 17 as the dryer 16 in Embodiments 1-6 and the sludge filter 26 in Embodiments 9-15, it installs like the figure (a) and (b). If the liquid refrigerant or the refrigerating machine oil does not accumulate in the dryer container 50 in the transient state, the liquid refrigerant or the refrigerating machine oil cannot flow out from the container 50. On the other hand, as shown in FIG. 5C, when the refrigerant flow direction is arranged from the top to the bottom, the liquid refrigerant or refrigerating machine oil that has flowed into the container 50 flows out quickly, so that it is quickly and stably It can be in operation and the refrigeration oil is not depleted from the compressor.

Embodiment 17. FIG.
FIG. 18 is a longitudinal sectional view showing an example of the accumulator 4 according to the seventeenth embodiment used in each of the above-described embodiments. In the figure, reference numeral 60 denotes an accumulator container, and 61 denotes the inside of the container from the bottom of the container 60. An inflow pipe inserted up to the upper part, 62 is inserted from the bottom of the container 60 to the upper part in the container, and an outflow pipe provided with an oil return hole 5 for returning the refrigeration machine oil to the lower part, 63 is provided in the lower part of the container 60 The liquid mixture of the stored liquid refrigerant and the refrigerating machine oil, 64 is an oil return pipe that connects the lower space inside the container 60 and the upper pipe end of the outflow pipe 62, and 65 is the oil return pipe 64 inside the container 60. It is an orifice provided at one end on the lower space side.

  Next, the oil return operation of the accumulator 4 will be described. The difference in height between the liquid level of the mixed liquid 63 in the accumulator and the pipe end of the outflow pipe 62 is h, the flow velocity of the refrigerant in the outflow pipe is u, the density of the refrigerant flowing out of the outflow pipe is ρg, When the density of the liquid 63 is ρl, the differential pressure ΔP generated before and after the orifice 65, which is obtained by subtracting the outlet pressure from the inlet pressure of the orifice 65, is expressed by ΔP = k1, ρg, u2, 2-k2, ρl, h. (Where k1 and k2 are positive constants). However, since the oil return pipe 64 is sufficiently thick, the pressure loss here is ignored. If ΔP is positive, it means that oil can be returned. If it is negative, it means that oil cannot be returned. Further, the larger the positive ΔP, the larger the oil return flow rate.

  As is clear from this equation, when the refrigerant flow rate u is large, the first term is larger than the second term on the right side, and oil can be returned even if the liquid level is low. On the other hand, if the refrigerant flow rate u is small, the negative amount of the second term is large even if the liquid level is somewhat high, and the flow rate of the mixed liquid flowing out to the outflow pipe 64 is small. When the refrigerant flow rate is large, the ratio of the refrigerating machine oil discharged from the compressor is large, but when the refrigerant flow rate is small, the ratio of the refrigerating machine oil discharged from the compressor is small. Therefore, when the refrigerating machine oil deterioration component adheres to the oil return hole 5, the oil return is insufficient when the refrigerant flow rate is large. When the oil return hole 5 is enlarged, the oil returns sufficiently when the refrigerant flow rate is high, but when the refrigerant flow rate is low and the liquid level of the accumulator 4 is high, the liquid back increases and the lubricity of the compressor increases. descend.

  However, as shown in FIG. 18, when the oil return pipe 64 is provided together with the oil return hole 5, the oil return flow rate becomes a problem due to the adhesion of sludge. The shortage of oil return due to sludge adhesion can be compensated. Further, even when the refrigerant flow rate is small and the liquid level of the accumulator 4 is high, the liquid back from the oil return pipe 64 is small, so that the lubricity of the compressor does not deteriorate due to excessive liquid back. Thus, by providing the oil return pipe 64 in the accumulator 4, even if sludge adheres to the oil return hole 5, there is no shortage of oil return, and there is no excessive liquid back. A high air conditioner can be obtained.

  When the orifice 65 of the oil return pipe 64 is provided at one end on the outflow pipe 62 side of the oil return pipe 64 as shown in FIG. 19, the oil return pipe 64 is constituted by a capillary tube 66 as shown in FIG. When both the function of the pipe 64 and the function of the orifice 65 are provided, as shown in FIG. 21, the outflow pipe 62 is inserted from above the container 60, the oil return pipe 64 is provided outside the container 60, and the oil return hole When the oil return pipe and the orifice 67 are provided in place of 5, the same effects as those of the seventeenth embodiment are obtained even when the outflow pipe 62 is U-shaped as shown in FIG.

Embodiment 18 FIG.
The eighteenth embodiment of the present invention will be described below with reference to FIGS. 23, 24 and 25. FIG. FIG. 23 is a block diagram showing the refrigerant circuit and control circuit of the air-conditioning apparatus according to the eighteenth embodiment, FIG. 24 is a block diagram showing the throttle device control apparatus according to the twenty-second embodiment, and FIG. It is a flowchart explaining an apparatus control operation. In the figure, A is a heat source unit, B, C and D are indoor units, 1 is a compressor, 2 is a switching valve, 3 is a heat source side heat exchanger, 4 is an accumulator, 5 is an oil return hole, 7b, 7c and 7d are indoor unit side heat exchangers, 8b, 8c and 8d are first expansion devices, 9 is a liquid side connection refrigerant pipe, 10 is a gas side connection refrigerant pipe, and the above is the same as the conventional example shown in FIG. belongs to.

  31 is a discharge pressure detecting means provided between the discharge portion of the compressor 1 and the switching valve 2, and 32 is a third pressure provided between the heat source machine side heat exchanger 3 and the liquid side connection refrigerant pipe 9. The temperature detecting means 33b, 33c, 33d are the fourth expansion units provided between the first expansion devices 8b, 8c, 8d in the indoor units B, C, D and the indoor heat exchangers 7b, 7c, 7d. The temperature detection means 34b, 34c, 34d are fifth temperature detection means 35 provided at one end of the indoor side heat exchangers 7b, 7c, 7d in the indoor units B, C, D on the gas side connection refrigerant pipe 10 side, 35 Is a throttling device control device, 36 is a detection value of the third temperature detection means 32 from the detection value of the third temperature detection means 32, the detection value of the first pressure detection means 31, and the calculation result of the composition calculation means 22 of the mixed refrigerant. SC calculation means 37 for calculating the degree of supercooling of the installation part, 37 is the fourth temperature detection means 33b SH calculating means for calculating the degree of superheat at the outlet portion of the indoor heat exchanger from the detected values of 33c and 33d and the detected values of the fifth temperature detecting means 34b, 34c and 34d; 38, SC calculating means 36; SH calculating means 37 First throttle device control means 39b, 39c, 39d for controlling the opening degree of the first throttle devices 8b, 8c, 8d from the calculation result of the above, blowers provided in the indoor units B, C, D, 40b, 40c and 40d are drain pumps provided in each of the indoor units B, C and D, and 41b, 41c and 41d are defrost control devices.

  During cooling and heating of the main refrigerant circuit including the compressor 1, the switching valve 2, the heat source device side heat exchanger 3, the first expansion devices 8b, 8c and 8d, and the indoor unit side heat exchangers 7b, 7c and 7d Since the refrigerant flow is exactly the same as in the conventional example, the description thereof will be omitted, and the control operation of the first expansion devices 8b, 8c, and 8d by the expansion device control device will be described with reference to the flowchart of FIG. In step 105, a calculation result SH calculated by the SH calculation means 37 from the detection values of the fourth temperature detection means 33b, 33c, 33d and the detection values of the fifth temperature detection means 34b, 34c, 34d is set in advance. The SH upper limit value SHH is compared, and if SH ≦ SHH, the process proceeds to step 106, and if SH> SHH, the process proceeds to step 108. In step 106, the calculation result SH of the SH calculation means 36 is compared with a preset lower limit value SH of SH, and if SH ≧ SHL, the routine proceeds to step 107, where the first throttling devices 8b, 8c, 8d. If the opening is decreased and SH <SHL, nothing is done. In step 108, the opening Sj of the first expansion devices 8b, c, d is compared with a preset upper limit opening MAX, and if Sj ≦ MAX, the routine proceeds to step 109 and the first expansion device 8b, If the opening degree of 8c, 8d is increased and Sj> MAX, the routine proceeds to step 110.

  In step 110, the calculation result calculated by the SC calculation means 36 from the detection value of the third temperature detection means 32, the detection value of the first pressure detection means 31, and the calculation result of the composition calculation means 22 of the mixed refrigerant; The SC lower limit value SCL set in advance is compared. If SC> SCL, the routine proceeds to step 111 where the upper limit opening MAX is set to a larger value, and if SC ≦ SCL, nothing is done. As described above, when the first expansion devices 8b, 8c, and 8d are insufficient in flow rate due to sludge adhesion, the supercooling is sufficiently ensured in a certain portion of the third temperature detecting means 32, and the control is diverged. If not, the shortage of flow is eliminated because the maximum opening is set large.

Embodiment 19. FIG.
A nineteenth embodiment of the present invention will be described below with reference to FIGS. 23, 26 and 27. FIG. FIG. 26 is a block diagram showing a defrosting control apparatus according to the nineteenth embodiment, and FIG. 27 is a flowchart for explaining the defrosting control operation. In FIG. 26, 34b, 34c, 34d are fifth temperature detecting means 39b provided at one end of the indoor side heat exchangers 7b, 7c, 7d in the indoor units B, C, D on the gas side connection refrigerant pipe 10 side. 39c, 39d are blowers provided in the indoor units B, C, D, 40b, 40c, 40d are drain pumps provided in the indoor units B, C, D, and 41b, 41c, 41d are defrost control devices. , 42 is a system mode determination means for determining whether or not the system mode is cooling, and 43b, 43c and 43d are indoor units for determining whether or not the mode of each of the indoor units B, C and D is cooling. Mode determining means, 44b, 44c, 44d are time measuring means for each of the indoor units B, C, D, 45 is an indoor unit that controls the operation for defrosting the heat exchanger of the indoor unit that is not cooled. It is a frost operation control means.

  When some of the indoor units, for example, B are in cooling operation, the room temperature and the outside air temperature are low, and the remaining indoor units C and D are stopped, the first throttle device 8d of the stopped indoor units C and D is There is a case where a minute flow rate of refrigerant flows without being completely closed by the attached sludge. In this case, since there is no heat for gasifying the minute flow rate refrigerant and the room temperature and the outside air temperature are low, the indoor side heat exchangers 7d of the stopped indoor units C and D are frosted. When falling into such a state, the temperature of the fifth temperature detecting means 34c, 34d of the indoor units C, D becomes low. When the detected value T5 of the fifth temperature detecting means 34c, 34d of the indoor units C, D is lower than the preset first predetermined temperature TL for the first predetermined time τ1B, this is the fifth Temperature detection means 34c, 34d, system mode determination means 42, indoor unit mode determination means 43c, 43d and timing means 44c, 44d are detected, and indoor unit defrosting operation control means 45 detects blowers 39c, 39d. It is operated to defrost the indoor heat exchangers C and D, and at the same time, the drain pumps 40c and 40d are also operated and controlled to drain the drain water generated at this time.

  Further, after the second predetermined time τ2B has elapsed after the start of the operation of the blowers 39c and 39d, the second detection value T5 of the fifth temperature detection means 34c and 34d of the indoor units C and D is preset to be higher than TL. When the temperature is higher than the predetermined temperature TH, the fans 39c and 39d are stopped, and the drain water continues to be generated for a while after the fans 39c and 39d are stopped. Therefore, after the third predetermined time τ3B elapses after the fans 39c and 39d stop. The pumps 40c and 40d are controlled to stop. As described above, the frost on the indoor side heat exchanger of the stopped indoor unit continues to grow even when the closed state cannot be completely closed by the sludge attached to the first throttle device of the stopped indoor unit. There is no problem.

  Next, the control operation of the indoor unit defrosting operation control means 45 will be described with reference to the flowchart of FIG. As a result of the determination by the system mode determination means 42, the system mode is cooling, and as a result of the determination by the indoor unit mode determination means 43b, 43c, 43d, the indoor unit mode is not cooling, and the timing means 44b , 44c, 44d, when the first time τ1 has passed the first predetermined time τ1B and the detection value T5 of the fifth temperature detection means 34b, 34c, 34d is equal to or lower than the first predetermined temperature TL 112, the process proceeds to step 116 through steps 113, 114, 115, the second timing τ2 by the timing means 44b, 44c, 44d is cleared to 0 and the process proceeds to step 117, and the blowers 39b, 39c, 39d and the drain pumps 40b, 40c , 40d is started.

  Thereafter, the routine proceeds to step 118, and whether the second time τ2 has passed the second predetermined time τ2B, the routine proceeds to step 119, where the detected value T5 of the fifth temperature detecting means 34b, 34c, 34d is higher than the second predetermined temperature TH. This determination is continued until these conditions are satisfied. When the conditions are satisfied, the routine proceeds to step 120, where the operation of the fans 39b, 39c, 39d is stopped, and in step 121, the timing means 44b, 44c, 44d. The third time τ3 is cleared to 0, and the process proceeds to step 122. After the third time τ3 has elapsed for the third predetermined time τ3B, the process proceeds to step 123, and the drain pumps 40b, 40c, 40d are stopped.

The refrigerant circuit diagram of the air conditioning apparatus concerning Embodiment 1 of this invention. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 2. FIG. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 3. FIG. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 4. FIG. FIG. 6 is a refrigerant circuit diagram of an air-conditioning apparatus according to Embodiment 5. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 6. FIG. FIG. 10 is a block diagram relating to composition calculation of the air-conditioning apparatus according to the seventh embodiment. 18 is a flowchart showing the operation of the composition calculating means of the air conditioner according to the seventh embodiment. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 8. FIG. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 9. FIG. FIG. 12 is a refrigerant circuit diagram of the air-conditioning apparatus according to Embodiment 10. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 11. FIG. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 12. FIG. FIG. 16 is a refrigerant circuit diagram of an air-conditioning apparatus according to Embodiment 13. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 14. FIG. The refrigerant circuit figure of the air conditioning apparatus concerning Embodiment 15. FIG. The longitudinal cross-sectional view which shows Embodiment 16 of the dryer used in Embodiment 1-6. The longitudinal cross-sectional view which shows the accumulating state 17 concerning Embodiment 17 used in each embodiment. A longitudinal sectional view showing an 18th embodiment of an accumulator. A longitudinal sectional view showing an embodiment 19 of an accumulator. A longitudinal section showing one embodiment 20 of an accumulator. A longitudinal sectional view showing an embodiment 21 of an accumulator. The block diagram which shows the refrigerant circuit and control circuit of the air conditioning apparatus concerning Embodiment 22 and 23. FIG. FIG. 23 is a block diagram showing a diaphragm control device according to a twenty-second embodiment; 23 is a flowchart for explaining a diaphragm device control operation according to a twenty-second embodiment; FIG. 23 is a block diagram showing a defrost control device according to a twenty-third embodiment. 24 is a flowchart for explaining a defrosting control operation according to a twenty-third embodiment. The refrigerant circuit figure of the conventional air conditioning apparatus.

Explanation of symbols

 A heat source unit, B, C, D indoor unit, 1 compressor, 2 switching valve, 3 heat source unit side heat exchanger, 4 accumulator, 5 oil return hole of accumulator, 6 second throttling device ( 7b, 7c, 7d indoor unit side heat exchangers, 8b, 8c, 8d first expansion device (cooling time expansion device), 9 liquid side connection refrigerant pipe, 10 gas side connection refrigerant pipe, 15 Bypass circuit, 16 dryer, 17 Third expansion device (bypass expansion device), 18, 27 Bypass heat exchanger, 18a First bypass heat exchanger, 18b Second bypass heat exchanger, 19 First temperature detection Means, 20 second temperature detecting means, 21 suction pressure detecting means, 22 composition calculating means, 23 oil separator, 24 oil return bypass circuit, 25 fourth throttling device, 26 sludge filter, 28 liquid refrigerant injection circuit, 29 Liquid injection circuit heat exchanger , 30 fifth throttling device, 31 discharge pressure detecting means, 32 third temperature detecting means, 33b, 33c, 33d fourth temperature detecting means, 34b, 34c, 34d fifth temperature detecting means, 35 throttling device control Device, 36 SC calculation means, 37 SH calculation means, 38 throttling device control means, 39b, 39c, 39d defrost blower, 40b, 40c, 40d drain pump, 41b, 41c, 41d defrost control device, 62 accumulator Outflow piping, 64 oil return piping.

Claims (7)

  An air conditioner comprising a main refrigerant circuit composed of a compressor, a condenser, a throttle device, and an evaporator, using a hydrofluorocarbon refrigerant as a working medium, and using an oil compatible with the refrigerant as a refrigerator oil In the apparatus, the refrigerant pipe is branched from the refrigerant pipe between the condenser and the throttle device, and is connected to the refrigerant pipe between the throttle device of the main refrigerant circuit and the compressor via a dryer and a bypass throttle device that absorb moisture. An air conditioner provided with a bypass circuit.   An air conditioner comprising a main refrigerant circuit composed of a compressor, a condenser, a throttle device, and an evaporator, using a hydrofluorocarbon refrigerant as a working medium, and using an oil compatible with the refrigerant as a refrigerator oil In the apparatus, a bypass circuit is provided that branches from the refrigerant pipe on the discharge side of the compressor and is connected to the refrigerant pipe on the suction side of the compressor via a dryer that absorbs moisture and a bypass throttling device. Air conditioner to do.   The air conditioner according to claim 1 or 2, wherein a bypass heat exchanger for cooling the refrigerant flowing into the dryer is provided in the middle of the bypass.   A heat source device comprising a compressor, a switching valve, a heat source device side heat exchanger and a heating time expansion device, an indoor unit comprising a cooling time expansion device and an indoor heat exchanger, and one end of the heat source device on the heating time expansion device side Connecting a liquid-side refrigerant pipe connecting one end of the indoor unit to the cooling-time expansion device side, one end on the switching valve side of the heat source unit, and one end on the indoor heat exchanger side of the indoor unit In an air conditioner comprising a main refrigerant circuit having a side connection refrigerant pipe, using a hydrofluorocarbon refrigerant as a working medium, and using oil compatible with the refrigerant as a refrigerating machine oil, the liquid side connection refrigerant A dryer that branches off from the pipe and absorbs moisture, a bypass throttling device, and a bypass heat exchanger that cools the refrigerant flowing into the dryer, and is connected to a refrigerant pipe between the compressor suction portion and the switching valve Bypass circuit An air conditioning apparatus characterized by comprising.   A heat source unit composed of a compressor, a switching valve and a heat source unit side heat exchanger, an indoor unit composed of an expansion device and an indoor side heat exchanger, one end of the heat source unit on the heat source unit side heat exchanger side, and the indoor unit A liquid-side connection refrigerant pipe that connects one end of the expansion device side; and a gas-side connection refrigerant pipe that connects one end of the heat source unit on the switching valve side and one end of the indoor unit on the indoor side heat exchanger side. In an air conditioner that includes a main refrigerant circuit, uses a hydrofluorocarbon refrigerant as a working medium, and uses oil that is compatible with the refrigerant as refrigeration oil, between the compressor discharge section and the switching valve. A bypass circuit connected to the refrigerant pipe between the compressor suction portion and the switching valve via a bypass heat exchanger for cooling the refrigerant, a dryer for absorbing moisture, and a bypass throttle device. It is characterized by having provided Air-conditioning apparatus.   A hydrofluorocarbon mixed refrigerant is used as a working medium, and a first temperature detection means provided at the inlet of the bypass expansion device and a second temperature detection provided downstream of the bypass expansion device in the middle of the bypass Means, a suction pressure detection means provided in the compressor suction section, and a composition calculation means for calculating the composition of the refrigerant based on the detected values of the first and second temperature detection means and the suction pressure detection means. The air conditioner according to any one of claims 1 to 5, wherein   The air conditioner according to any one of claims 1 to 6, wherein the dryer is mounted downward with respect to the flow direction.

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