JP2009299911A - Refrigeration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigeration device capable of preventing increase of pressure loss in a gas side connection pipe having low pressure or the like even if using refrigerant having large specific volume such as HFO-1234yf in refrigeration cycle to ensure satisfactory refrigeration performance. <P>SOLUTION: In this refrigeration device, an outdoor unit 100 provided with a compressor 1, an outdoor heat exchanger 3, a heat exchanger 8 for overcooling, an outdoor pressure reducing device 7, and an ejector 5 and an indoor unit 200 provided with an indoor heat exchanger 11 are mutually connected by a refrigerant pipe to constitute the refrigeration cycle. A part of liquid refrigerant fed into the heat exchanger operating as an evaporator is bypassed, pressure of the bypassed refrigerant is reduced to let this refrigerant flow into the heat exchanger for overcooling, and a main stream of the liquid refrigerant is cooled by the heat exchanger for overcooling and is supplied into the indoor heat exchanger. The bypassed refrigerant evaporated after exchanging heat with the main stream refrigerant is sucked by the ejector and then flows into a gas-liquid separator 6. The gas refrigerant in the gas-liquid separator has high pressure exceeding suction pressure of the compressor and is sucked into the compressor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus provided with a refrigeration cycle such as an air conditioner or a refrigerator, and in particular, with a supercooling heat exchanger, the main stream side of liquid refrigerant sent to an evaporator is supercooled by a bypass flow side refrigerant. The present invention relates to a refrigeration apparatus.

  Using a double-tube heat exchanger or the like provided on the condenser outlet side, the liquid refrigerant sent to the evaporator bypasses part of the refrigerant and is reduced in pressure to reduce the temperature by exchanging heat. As an air conditioner to be cooled, a conventional technique disclosed in Japanese Patent Laid-Open No. 2000-18737 (Patent Document 1) is known.

  In an air conditioner equipped with such a supercooling heat exchanger, the amount of refrigerant circulating to the evaporator is reduced, so that the pressure loss of the evaporator and the connecting piping can be reduced and the coefficient of performance can be improved. Are known.

  In addition to the supercooling heat exchanger, the refrigeration system is equipped with an ejector, and when it is bypassed and expanded by the ejector, the expansion power is recovered, thereby reducing the expansion loss during decompression and improving the coefficient of performance. As a device, a conventional technique disclosed in Japanese Patent Application Laid-Open No. 2007-78318 (Patent Document 2) is known.

JP 2000-18737 A JP 2007-78318 A

  At present, so-called HFC refrigerants (Hydrofluorocarbons) such as R-410A, R-407C or R-404A, which are widely used as refrigerants for vapor compression refrigeration apparatuses such as air conditioners and refrigerators, From the viewpoint of prevention of globalization, conversion to a refrigerant having a lower GWP (global warming potential) has been studied.

  Natural refrigerants such as R-290 (propane), R-717 (ammonia), and R-744 (carbon dioxide) have been studied as alternative refrigerant candidates, but air is flammable, toxic, or efficient. It has become clear that application to a harmony machine etc. is difficult. Under such circumstances, low GWP refrigerants such as HFO-1234yf (2,3,3,3-Tetrafluoropropene) capable of improving these problems are being developed.

  However, low GWP refrigerants such as HFO-1234yf have a larger specific volume of gas refrigerants at the same saturation temperature than refrigerants such as R-410A conventionally used in air conditioners, and are applied to conventional systems. In such a case, there is a concern that the pressure loss on the low pressure side will increase.

  In particular, a so-called multi-air conditioner for a building in which a plurality of indoor units are connected to a system of the same refrigerant system is a system that has a relatively long connection pipe length and is easily affected by pressure loss.

  Measures to reduce the pressure loss include expansion of the refrigerant pipe diameter and increase in the number of heat transfer pipe passages in the evaporator, but these methods increase material costs, processing costs, and construction costs for connecting piping. When renewing an old air conditioner, the existing refrigerant connection pipes used when using conventional refrigerants such as R-22 and R-410A are used. This makes it impossible to use the resources and increases the number of construction man-hours.

  Therefore, instead of these, means for reducing the low pressure side pressure loss is required. However, in the conventional technique disclosed in Patent Document 1, the outlet side of the low pressure refrigerant flowing into the supercooling heat exchanger is connected to the compressor suction side. Due to the connected relationship, the supercooled liquid refrigerant cannot be lower than the saturation temperature of the compressor suction pressure.

  For this reason, when a refrigerant with a large specific volume that tends to increase the pressure loss of the gas side connection pipe or the evaporator is used, the effect of reducing the pressure loss is insufficient, so the cooling capacity is insufficient or the coefficient of performance is decreased. There is a problem.

  Moreover, in the prior art shown by the said patent document 2, although the efficiency of a freezing apparatus can be improved by collect | recovering expansion power using an ejector, the outlet refrigerant | coolant of an ejector is used as the heat exchanger for supercooling Therefore, the temperature of the refrigerant sent to the evaporator cannot be made equal to or lower than the saturation temperature of the compressor suction pressure, as in the prior art (Patent Document 1). Moreover, since the refrigerant whose pressure has been increased by the ejector flows into the supercooling heat exchanger, the compressor suction pressure is reduced due to the pressure loss of the supercooling heat exchanger, so the power recovery effect at the ejector There is a problem that cannot be fully demonstrated.

  An object of the present invention is to obtain a refrigeration apparatus that can sufficiently secure the capacity by sufficiently suppressing the pressure loss associated with the refrigerant circulation on the low-pressure side by increasing the degree of supercooling of the liquid refrigerant sent to the evaporator.

  Another object of the present invention is to reduce expansion loss by providing a mechanism for recovering expansion power from a refrigerant compressed by using an ejector or a combination of an expander and an auxiliary compressor and performing a pressurizing action. It is to obtain a refrigeration apparatus that can improve efficiency.

  In order to solve the above-described problems of the prior art, the present invention includes a compressor, an outdoor heat exchanger, a supercooling heat exchanger, an outdoor decompression device, an outdoor unit including a pressure boosting unit, and an indoor heat exchanger. In an apparatus having a refrigeration cycle in which indoor units are connected to each other by refrigerant piping, the bypass refrigerant that bypasses part of the liquid refrigerant sent to the heat exchanger acting as an evaporator is decompressed, and the supercooling heat exchanger The refrigerant on the main stream side of the liquid refrigerant is cooled by the supercooling heat exchanger and sent to the indoor heat exchanger, and the evaporated bypass refrigerant is boosted to a pressure higher than the suction pressure of the compressor by the boosting means. It is characterized by making it.

  In the above, an ejector can be used as the boosting means.

  Here, a gas-liquid separator is provided on the outlet side of the ejector, the refrigerant flowing out from the heat exchanger acting as a condenser is caused to flow into the ejector, and the refrigerant flowing out from the ejector is caused to flow into the gas-liquid separator. The refrigerant flowing out from the gas side outlet of the gas-liquid separator is returned to the compressor, and the bypass refrigerant obtained by bypassing a part of the refrigerant flowing out from the liquid side outlet of the gas-liquid separator is decompressed by the outdoor pressure reducing device. The refrigerant on the main stream side of the liquid refrigerant is cooled by the supercooling heat exchanger and sent to the indoor heat exchanger, and the bypass refrigerant gasified by the supercooling heat exchanger is supplied to the intake port of the ejector It is good to make it the structure made to suck from.

  Further, a gas-liquid separator is provided on the outlet side of the ejector, and a bypass refrigerant obtained by bypassing a part of the refrigerant from the heat exchanger acting as a condenser is caused to flow into the ejector, and the refrigerant that has flowed out of the ejector is Flowing into the gas-liquid separator, returning the refrigerant flowing out from the gas-side outlet of the gas-liquid separator to the compressor, reducing the refrigerant flowing out from the liquid-side outlet of the gas-liquid separator with the outdoor pressure reducing device, The bypass from which the mainstream refrigerant of the refrigerant from the heat exchanger acting as the condenser is cooled by the supercooling heat exchanger and sent to the indoor heat exchanger and is gasified by the supercooling heat exchanger The refrigerant may be sucked from the suction port of the ejector.

In the above, an auxiliary compressor can also be used as the pressure increasing means.
Here, an expander that recovers power by expanding the refrigerant that has flowed out of the heat exchanger acting as a condenser is provided, and bypass refrigerant that bypasses part of the refrigerant that has flowed out of the expander is bypassed by the outdoor pressure reducing device. The refrigerant is depressurized and flows into the supercooling heat exchanger, the main-stream-side refrigerant that is the other refrigerant flowing out of the expander is cooled, sent to the indoor heat exchanger, and evaporated in the supercooling heat exchanger The bypass refrigerant may be configured to be sucked into the compressor after being boosted to a pressure higher than the suction pressure of the compressor by the auxiliary compressor operated by the power recovered by the expander.

  And an expander that recovers power by depressurizing and expanding a bypass refrigerant that bypasses a part of the refrigerant that has flowed out of the heat exchanger that acts as a condenser, and the refrigerant that has flowed out of the heat exchanger that acts as the condenser. The other main stream side refrigerant is cooled in the supercooling heat exchanger by the bypass refrigerant and sent to the indoor heat exchanger, and the bypass refrigerant evaporated in the supercooling heat exchanger is the expander. The auxiliary compressor that is operated by the recovered power may be increased to a pressure higher than the suction pressure of the compressor and sucked into the compressor.

  In the above, a bridge circuit constituted by a check valve is provided, and the direction of the refrigerant flow path of the ejector and the supercooling heat exchanger is set in the same direction during both cooling and heating operation using the bridge circuit. It can also be configured.

  In addition, a bridge circuit including a check valve is provided, and the direction of the refrigerant flow path of the auxiliary compressor and the supercooling heat exchanger is the same in both the cooling and heating operation using the bridge circuit. It can also be configured to be.

  Furthermore, the present invention is applied to a refrigerant having a specific volume of saturated gas at the same evaporation temperature of the refrigerant used that is 1.5 times or more that of R-410A (preferably about 1.5 to 2.5 times the refrigerant) Then it is more effective.

  According to the present invention, since the degree of supercooling of the liquid refrigerant sent to the evaporator can be increased, the refrigerant circulation amount sent to the evaporator is reduced and the low pressure side pressure loss is reduced without reducing the refrigeration capacity. The reduction effect can be increased. Therefore, even when a refrigerant having a large specific volume is used, it is possible to obtain a refrigeration apparatus that can sufficiently generate refrigeration capacity without increasing the diameter of the refrigerant pipe.

  In addition, according to the present invention, since the expansion power of the compressed refrigerant can be recovered, a refrigeration apparatus capable of efficient operation is obtained.

  Adopting a refrigerant with a large specific volume (for example, a refrigerant with a specific volume of about 1.5 to 2.5 times that of R-410A and mainly a refrigerant with a low global warming potential (low GWP refrigerant)) Then, the capability unachieved resulting from the pressure loss of gas connection piping arises. This problem is difficult to cope with by increasing the compressor discharge rate and heat exchanger. Although the problem can be solved by increasing the pipe diameter, it is necessary to replace the pipe with a large refrigerant pipe. In the present invention, by sufficiently supercooling the refrigerant, a configuration capable of exhibiting the capability even when the refrigerant mass flow rate is small can ensure sufficient capability without replacing the refrigerant pipe with a large diameter.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In each embodiment, parts denoted by the same reference numerals indicate the same or corresponding parts. In addition, an air conditioner will be described as an example of the refrigeration apparatus of the present invention, but the present invention can be similarly applied to any apparatus using a refrigeration cycle such as a refrigerator for a showcase.

  The air conditioner of Example 1 of this invention is demonstrated using FIGS. 1-3.

  First, an outline of the air conditioner of the embodiment will be described with reference to FIG. FIG. 1 is a configuration diagram of a refrigeration apparatus for an air conditioner according to the present embodiment.

  The air conditioner includes an outdoor unit 100, an indoor unit 200, a liquid side connection pipe 9 and a gas side connection pipe 13 that connect them.

  The outdoor unit 100 includes a compressor 1 that compresses the refrigerant, an outdoor heat exchanger 3 that performs heat exchange between the outdoor air and the refrigerant, and expands and depressurizes the refrigerant. Supercooling by the ejector 5 to be compressed, the gas-liquid separator 6 that separates the gas-liquid two-phase refrigerant from the liquid refrigerant and the gas refrigerant, the outdoor decompression device 7 that depressurizes the liquid refrigerant, and the refrigerant bypassed and depressurized. And a two-way valve 20 for opening and closing a circuit for returning the gas refrigerant separated by the gas-liquid separator 6 to the suction side of the compressor 1 as components of the refrigeration apparatus. I have.

  Here, the outdoor unit 100 is provided with an outdoor blower 4 for passing outdoor air through the outdoor heat exchanger 3.

  The indoor unit 200 includes an indoor heat exchanger 11 that performs heat exchange between indoor air and a refrigerant, and an indoor decompressor 10 that adjusts the outlet state of the indoor heat exchanger 11 or the refrigerant flow rate.

  And the indoor unit 200 is provided with the indoor air blower 12 which ventilates indoor air to the indoor heat exchanger 11.

  Next, the operation of the refrigeration apparatus and the state change of the refrigerant during the cooling operation of the air conditioner will be described with reference to FIGS. FIG. 2 is a Mollier diagram showing a state change during the cooling operation in the air conditioner of FIG. Here, the case where the refrigerant is R-134a (1,1,1,2-Tetrafluoroethane) is shown as an example, but other refrigerants such as HFO-1234yf (2,3,3,3-Tetrafluoropropene) are used. Even if it is used, the following description is the same and is not limited to the type of refrigerant. However, the effect of the present invention is particularly great if the specific volume of saturated steam at the same temperature is 1.5 times or more larger than that of conventionally used refrigerants such as R-410A.

  FIG. 3 is a diagram for explaining the structure and operation of the ejector shown in FIG.

  During the cooling operation, the two-way valve 20 is opened, and the refrigerant circulates in the arrow direction shown in FIG.

  That is, the refrigerant is compressed by the compressor 1 (a → b in FIG. 2), cooled by outdoor air in the outdoor heat exchanger 3 (b → c in FIG. 2), and flows into the nozzle of the ejector 5.

  As shown in FIG. 3, the ejector includes a nozzle portion 51 that discharges the refrigerant by reducing its pressure lower than the suction pressure of the compressor 1, a refrigerant jetted from the nozzle portion 51, and a suction portion 52 by the jetted refrigerant. A mixing unit 53 that mixes the refrigerant sucked through, a diffuser unit 54 that decelerates the mixed refrigerant and restores the pressure to the suction pressure of the compressor 1, and a needle 56 that adjusts the amount of decompression of the nozzle unit 51, And a coil 55 for controlling the needle 56.

  The high-pressure Ph refrigerant sent to the ejector 5 flows into the nozzle portion 51 from the first inflow port 57 at a refrigerant circulation amount Grm and is reduced to the pressure Pejes (c → d in FIG. 2). That is, the refrigerant passes through a state change close to an adiabatic change (isentropic change) in the nozzle portion 51 and is ejected at a high-speed gas-liquid two-phase flow at the outlet.

  The static pressure is reduced by the dynamic pressure generated at that time, and the low-pressure gas refrigerant (dg in FIG. 2) is sucked from the second inlet 58 into the suction part 52 with the refrigerant circulation amount Grb (d → dm in FIG. 2). , Dg → dm).

  The ejected refrigerant and the sucked refrigerant are mixed and compressed by the mixing unit 53 to become a refrigerant having a refrigerant circulation amount Grm + Grb and a static pressure Pejem. This refrigerant is decelerated by the expansion of the flow path cross-sectional area of the diffuser portion 54, and the static pressure is restored to Pejeo. Due to the state change in the series of these ejectors 5, the expansion power of the high-pressure refrigerant that has flowed into the nozzle 51 as a result is converted into the compression work (Pejes → Pejeo) of the suction gas refrigerant until the outlet 59 of the ejector 5 is reached. (Dm → f in FIG. 2).

  In addition, since the ejector 5 has a pressure reducing function and a pressure increasing function as described above, and has an effect of recovering expansion power, the irreversible loss accompanying expansion of the high-pressure refrigerant can be reduced.

  The gas-liquid two-phase refrigerant exiting the ejector 5 flows into the gas-liquid separator 6 and is separated into a gas refrigerant and a liquid refrigerant (f → fg: gas f → fL: liquid in FIG. 2). Among these, the gas refrigerant is returned to the suction side of the compressor 1 (fg → a in FIG. 2), and a part of the liquid refrigerant (circulation amount Grb: bypass flow side) is decompressed by the outdoor decompression device 7. (FL → j in FIG. 2), it flows into the supercooling heat exchanger 8, and the other (circulation amount Gre: main flow side) flows into the supercooling heat exchanger 8 as it is.

  The structure of the supercooling heat exchanger 8 is, for example, a double pipe, a plate heat exchanger, or a structure in which two pipes are brought into contact with each other and brazed to exchange heat from the high-temperature side refrigerant to the low-temperature side refrigerant. Is done.

  Here, since the bypass side refrigerant can be made lower than the compressor suction pressure, the temperature becomes lower than the saturation temperature of the compressor suction pressure, and the main stream side refrigerant exchanged with this bypasses the saturation temperature of the compressor suction pressure or less. It is cooled (fL → g in FIG. 2). At the same time, the bypass-side refrigerant is heated by the main-stream-side refrigerant and evaporates (j → dg in FIG. 2).

  The bypass-side refrigerant is sucked into the second inlet of the ejector 5, and the main-stream side refrigerant is sent to the indoor unit 200 through the liquid-side connection pipe 9, and after the pressure reduction amount is adjusted by the indoor pressure reducing device 10, the indoor heat exchanger 11 flows into. In the indoor heat exchanger 11, the indoor air sent from the indoor blower 12 and the refrigerant are heat-exchanged (h → i in FIG. 2), and the indoor air is cooled.

  Here, the specific enthalpy difference on the refrigerant side that contributes to the cooling capacity is greatly expanded as compared with the specific enthalpy difference Δhe in the normal cycle, as indicated by Δhescn in FIG. 2.

  The outlet refrigerant of the indoor heat exchanger 11 is returned to the outdoor unit 100 through the gas side connection pipe 13 and sucked into the compressor 1 (i → a in FIG. 2).

  The above shows a series of refrigerant circulation and cooling operations during cooling operation in the air conditioner of the present invention.

  On the other hand, the refrigeration cycle on the Mollier diagram shown in FIG. 4 shows the operating state of a normal refrigeration cycle and a conventional supercooling bypass cycle.

  The solid line in FIG. 4 shows the operation state of the normal cycle. During cooling operation, compression (a → b), condensation (b → c), decompression (c → d), and evaporation (d → i) are performed in this order. The refrigeration cycle operates. At this time, the specific enthalpy difference in the evaporator is indicated by Δheo in FIG.

  The broken line in FIG. 4 shows the operation state of the supercooling bypass cycle in the prior art (Patent Document 1, etc.). During cooling operation, compression (a ′ → b ′), condensation (b ′ → c), The main stream side is subcooled (c → c ′), decompressed (c ′ → d ′), evaporated (d ′ → i ′), and the bypass side is depressurized (c → e ′). The refrigeration cycle operates in the order of evaporation (e ′ → i ′). Here, the specific enthalpy difference at the time of mainstream evaporation is indicated by Δhesc, which is larger than that in the normal cycle.

  For this reason, the refrigerant circulation amount at the same cooling capacity is reduced, and the low pressure side pressure loss is reduced.

  FIG. 5 shows the relationship between the evaporator refrigerant specific enthalpy difference, the low-pressure pressure loss, and the refrigerant circulation rate at the same cooling capacity.

  Since the refrigerant specific enthalpy difference in the evaporator is enlarged in the order of the normal cycle, the conventional supercooling bypass cycle, and the supercooling cycle of the present invention, the refrigerant circulation amount decreases, and as a result, the pressure loss on the low pressure side is reduced. It is greatly reduced. For this reason, even when the gas side connection pipe 13 that connects the outdoor unit 100 and the indoor unit 200 is long or when the cross-sectional area of the flow path is not sufficiently large, it is difficult for the capacity to decrease, and a highly efficient cooling operation is possible. It becomes.

  Next, an air conditioner according to a second embodiment of the present invention will be described with reference to FIGS.

  FIG. 6 shows the configuration of the air conditioner refrigeration apparatus of Example 2 of the present invention, and the refrigerant state change during the cooling operation of the air conditioner is shown on the Mollier diagram of FIG.

  A rough difference from the first embodiment shown in FIG. 1 is that the ejector 5 is replaced with an expander 5 'and an auxiliary compressor 1', and the gas-liquid separator 6 is omitted. Since the functions are almost the same, only different parts will be described.

  The liquid refrigerant condensed in the outdoor heat exchanger 3 (c in FIG. 7) is decompressed by the expander 5 ′ to be in a gas-liquid two-phase state, and the power Wr is taken out (c → d in FIG. 7). Here, the expander 5 'operates in reverse to the compressor. For example, a volume type such as a scroll type, a rotary type, or a reciprocating type is used, and the function of converting the power generated at the time of expansion into rotational power is used. Made.

  The gas-liquid two-phase refrigerant at the outlet of the expander 5 '(d in FIG. 7) is partially bypassed (circulation amount Grb) and depressurized by the outdoor pressure reducing device 7 (d → g in FIG. 7), and heat for supercooling It flows into the exchanger 8. The remaining main stream side refrigerant flows from the other inlet of the supercooling heat exchanger 8 and is cooled by the low temperature bypass side refrigerant (d → e in FIG. 7). The bypass-side refrigerant evaporates in the process (g → h in FIG. 7) and flows into the auxiliary compressor 1 ′.

  Since the auxiliary compressor 1 ′ is driven by the power Wr of the expander 5 ′, the low pressure gas can be increased to a pressure higher than the suction pressure of the compressor 1 (h → a in FIG. 7). The expansion power is recovered by the operations of the expander 5 ′ and the auxiliary compressor 1 ′, and the power saving effect is the same as that of the first embodiment using the ejector.

  Here, the expander 5 ′ and the auxiliary compressor 1 ′ may have an integrated structure housed in the same pressure vessel. Moreover, the structure which united these two and the compressor 1 may be sufficient. Integration makes it possible to reduce the size and cost of the device. Further, since the storage location for the refrigerating machine oil used for lubricating the bearings and the like can be shared, it is easy to secure the oil level, which is effective for improving the reliability.

  The subcooled main stream side refrigerant is sent to the indoor unit 200 through the liquid side connection pipe 9, and after the pressure is adjusted by the indoor pressure reducing device 10 (e → f in FIG. 7), it flows into the indoor heat exchanger 11. To do. Here, the room air is cooled by heat exchange with the room air sent by the room blower 12, and a cooling operation is performed. At that time, the refrigerant is evaporated in the indoor heat exchanger 11 to be in a low pressure gas state (f → i in FIG. 7).

  Thereafter, the gas is returned to the outdoor unit 100 through the gas side connection pipe 13 (i → a in FIG. 7), and returned to the compressor 1 together with the bypass refrigerant from the auxiliary compressor 1 ′.

  As described above, also in the air conditioner of the second embodiment, the specific enthalpy of the refrigerant sent to the evaporator can be reduced similarly to the first embodiment, so that the specific enthalpy difference in the evaporator is expanded. As a result, the refrigerant circulation amount can be reduced, and the low-pressure pressure loss can be greatly reduced.

  Next, an air conditioner according to a third embodiment of the present invention will be described with reference to FIGS.

  FIG. 8 shows the configuration of the air conditioner refrigeration apparatus according to Embodiment 3 of the present invention, and the change in refrigerant state during the cooling operation of the air conditioner is shown on the Mollier diagram of FIG.

  The difference from the first embodiment (FIG. 1) is that the high-pressure liquid refrigerant at the outlet of the condenser is branched into two flow paths to the nozzle inlet of the ejector 5 and the supercooling heat exchanger 8. On the other hand, in Example 1, all the refrigerant | coolants at a condenser exit flow into the ejector 5. FIG. Since the other cycle configurations and operating states have much in common with the first embodiment, only the changes will be described.

  The high-pressure liquid refrigerant (c in FIG. 9) that exits the outdoor heat exchanger 3 that acts as a condenser during cooling operation is branched into two flow paths, and one of them flows into the ejector 5 as a bypass flow (circulation amount Grb). The other flows into the supercooling heat exchanger 8.

  In the ejector 5, the same operation as described in the first embodiment is performed, and adiabatic expansion (c → d in FIG. 9), low-pressure gas (dg in FIG. 9) discharged from the supercooling heat exchanger 8 and Are mixed (dm in FIG. 9), and the pressure increasing action (dm → f in FIG. 9) is performed, and the expansion power is recovered.

  Gas-liquid separation is performed by the gas-liquid separator 6 (a: gas, fL: liquid in FIG. 9), and the gas refrigerant is compressed together with oil from an oil return hole provided near the bottom of the gas-liquid separator 6. Returned to the machine suction side, the liquid refrigerant is decompressed by the outdoor decompression device 7 and flows into the supercooling heat exchanger 8.

  In the supercooling heat exchanger 8, the main-stream-side liquid refrigerant is cooled (c → g in FIG. 9) by the evaporation of the low-pressure bypass refrigerant (j → dg in FIG. 9). The main-stream-side refrigerant is sent to the indoor unit 200 through the liquid-side connection pipe 9, decompressed by the indoor decompression device 10 (g → h in FIG. 9), and flows into the indoor heat exchanger 11.

  In the indoor heat exchanger 11, heat is exchanged with room air sent by the indoor blower 12, and a cooling operation is performed. The specific enthalpy difference on the refrigerant side at this time is Δhe in the normal cycle, but is increased to Δhecn, so that the refrigerant circulation amount at the same cooling capacity is reduced, and the low pressure side pressure loss is greatly increased as in the first embodiment. Reduction is made.

  Moreover, the operational difference from Example 1 is that the liquid refrigerant sent to the indoor heat exchanger 11 acting as an evaporator remains in a high pressure state. Therefore, even when the indoor unit 200 is installed at a position higher than the outdoor unit 100 and the head difference of the liquid refrigerant caused by the height difference is large, the operation can be performed.

  Next, an air conditioner according to a fourth embodiment of the present invention will be described with reference to FIGS. 10 and 11.

  FIG. 10 shows the configuration of the air conditioner refrigeration apparatus according to Embodiment 4 of the present invention, and the change in refrigerant state during the cooling operation of the air conditioner is shown on the Mollier diagram of FIG.

  The difference from the second embodiment (FIG. 6) is that the high-pressure liquid refrigerant at the condenser outlet is branched into two flow paths to the expander 5 ′ inlet and the supercooling heat exchanger 8. On the other hand, in Example 2, all the refrigerant | coolants at a condenser exit flow into the expander 5 '. Since the other cycle configurations and operating states have much in common with the second embodiment, only the changes will be described.

  The high-pressure liquid refrigerant (c in FIG. 11) exiting from the outdoor heat exchanger 3 acting as a condenser during the cooling operation is branched into two flow paths, one flowing into the expander 5 'and the other for supercooling. It flows into the heat exchanger 8.

  In the expander 5 ′, as in the air conditioner of the second embodiment, the power generated when the refrigerant is expanded under reduced pressure is taken out as power Wr (c → d in FIG. 11). At this time, the pressure after depressurization becomes as low as PeL in FIG. 11 and flows into the supercooling heat exchanger 8.

  In the subcooling heat exchanger 8, the main-flow-side refrigerant is cooled by the bypass refrigerant that has been decompressed to a low temperature (c → d in FIG. 11). Therefore, this liquid refrigerant is sent to the indoor heat exchanger 11, and the specific enthalpy difference that contributes to the cooling capacity increases as compared with Δhescn and the normal cycle, and the circulation amount is reduced, so that the pressure loss is greatly reduced.

  Further, the bypass-side refrigerant evaporates in the supercooling heat exchanger 8 (d → e in FIG. 11), is compressed by the auxiliary compressor 1 ′, and is returned to the compressor 1. The necessary power at this time is covered by the power Wr recovered by the expander 5 '.

  As described in the third embodiment, the difference in effect from the second embodiment is that when the indoor unit 200 is installed above the outdoor unit 100 because the liquid refrigerant sent to the indoor unit 200 has a high pressure, The range in which the liquid head difference generated from the difference can be handled can be expanded.

  Next, the air conditioner of Example 5 of this invention is demonstrated using FIG.12 and FIG.13.

  FIG. 12 shows the configuration of a refrigerating apparatus for an air conditioner according to a fifth embodiment of the present invention, and changes in the refrigerant state during the cooling operation of the air conditioner are shown on the Mollier diagram of FIG.

  The difference from the air conditioner of the fourth embodiment is that the auxiliary compressor 1 'is operated with different power without having the expander 5'. For this reason, the recovery operation of the expansion power is not performed, but the other operations and effects are the same. As shown in FIG. 13, the specific enthalpy difference in the evaporator can be expanded, and the low-pressure pressure loss is greatly reduced. Therefore, it is easy to ensure the cooling capacity even when a long pipe is connected or when the cross-sectional area of the pipe is not sufficiently large.

  Further, unlike the case where there is an expansion power recovery mechanism, the amount of pressure increase and refrigerant circulation amount of the auxiliary compressor 1 ′ can be arbitrarily controlled, so that the degree of supercooling of the liquid refrigerant sent to the evaporator can be arbitrarily set It becomes possible to control.

  Moreover, since the structure of a freezing apparatus can be simplified compared with the air conditioner of Examples 1-4, it is advantageous to cost reduction and high reliability.

  Next, the air conditioner of Example 6 of this invention is demonstrated using FIG. FIG. 14 shows the configuration of a refrigerating apparatus for an air conditioner according to Embodiment 6 of the present invention.

  Here, although the refrigerating apparatus using the check valve bridge circuit using the check valves 21a to 21d based on the refrigerating apparatus of the air conditioner of the first embodiment is shown, the air conditioners of the second to fifth embodiments are shown. The effects described below are the same even in a refrigeration apparatus having a check valve bridge circuit based on the configuration of the refrigeration apparatus of the machine.

  When the check valve bridge circuit of FIG. 14 using the check valves 21a to 21d is used, the ejector 5 and the gas liquid are used in both the cooling operation and the heating operation in which the refrigerant flow direction is reversed by the switching operation of the four-way valve 2. The flow paths of the separator 6, the outdoor pressure reducing device 7, the supercooling heat exchanger 8, and the two-way valve 20 are the same. As a result, not only in cooling operation but also in heating operation, a significant reduction effect of low pressure side pressure loss obtained by reducing the low pressure side refrigerant circulation amount due to expansion of refrigerant side specific enthalpy difference in the evaporator can be exhibited, Capability can be secured and COP can be improved.

  In particular, in heating operation at low temperatures, where the low pressure side pressure loss tends to increase, the effect of reducing the low pressure side pressure loss is increased, and the heating capacity can be increased and the start-up of the capacity can be improved. In addition, energy saving is realized.

  Further, even when a plurality of indoor units are connected to the same refrigerant system as the indoor units 200a and 200b, the indoor decompression devices 10a and 10b are required by controlling the refrigerant circulation amount necessary for each indoor unit. It becomes possible to demonstrate the capability according to the air conditioning load. Only the air conditioner (indoor unit 200, outdoor unit 100) is updated, and the existing liquid side connection pipe 9 and gas side connection pipe 13 may be reused.

  Such a construction method eliminates the need to reconstruct the refrigerant pipe embedded in the ceiling, the wall surface, and the like, and realizes renewal with a small amount of material and in a short time. Therefore, the ratio is increasing year by year.

  However, refrigerants with a relatively small specific volume such as R-22, R-407c, and R-410A are often used in the air conditioner before the update, and the saturated gas specific volume at the same temperature after these is updated When a larger refrigerant is used, the diameter (cross-sectional area) of the gas side connection pipe cannot be said to be sufficient, and the cooling capacity is insufficient due to the pressure loss of the gas side connection pipe 13 as it is. Resulting in.

  According to the air conditioners of Embodiments 1 to 6 of the present invention, even when an existing pipe whose cross-sectional area of the gas side connection pipe is insufficient is used, the cooling capacity can be sufficiently exhibited.

The refrigeration cycle block diagram which shows Example 1 of the freezing apparatus of this invention. The Mollier diagram which shows the air_conditionaing | cooling operation state in the freezing apparatus shown in FIG. The internal structure figure of the ejector shown in FIG. 1, and the diagram which shows the static pressure distribution at the time of an action | operation. The Mollier diagram which shows the driving | running state at the time of air_conditioning | cooling in the conventional freezing apparatus. The diagram explaining the relationship between the specific enthalpy difference on the evaporator refrigerant side, the refrigerant circulation amount, and the low pressure side pressure loss at the same cooling capacity in the conventional and the refrigeration apparatus of the present invention. The refrigeration cycle block diagram which shows Example 2 of the freezing apparatus of this invention. The Mollier diagram which shows the air_conditioning | cooling driving | running state in the freezing apparatus shown in FIG. The refrigeration cycle block diagram which shows Example 3 of the freezing apparatus of this invention. The Mollier diagram which shows the air_conditioning | cooling driving | running state in the freezing apparatus shown in FIG. The refrigeration cycle block diagram which shows Example 4 of the freezing apparatus of this invention. The Mollier diagram which shows the air_conditioning | cooling driving | running state in the freezing apparatus shown in FIG. The refrigeration cycle block diagram which shows Example 5 of the freezing apparatus of this invention. The Mollier diagram which shows the air_conditioning | cooling driving | running state in the freezing apparatus shown in FIG. The refrigeration cycle block diagram which shows Example 6 of the freezing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Outdoor fan 5 Ejector 6 Gas-liquid separator 7 Outdoor decompression device 8 Supercooling heat exchanger 9 Liquid side connection piping 10 Indoor decompression device 11 Indoor heat exchanger 12 Indoor blower 13 Gas side connection piping 100 Outdoor unit 200 Indoor unit

Claims (10)

In an apparatus having a refrigeration cycle in which a compressor, an outdoor heat exchanger, a supercooling heat exchanger, an outdoor unit equipped with an outdoor decompressor, and an indoor unit equipped with an indoor heat exchanger are connected to each other by a refrigerant pipe,
The bypass refrigerant obtained by bypassing a part of the liquid refrigerant sent to the heat exchanger acting as an evaporator is depressurized and flows into the supercooling heat exchanger, and the main stream side refrigerant of the liquid refrigerant is converted into the supercooling heat. The refrigerant is cooled by an exchanger and sent to the indoor heat exchanger, and the bypass refrigerant evaporated by the supercooling heat exchanger is boosted by a boosting means that boosts the suction pressure to be higher than the suction pressure of the compressor, and then the compressor A refrigeration apparatus characterized in that the inhalation side is configured to inhale.   2. The refrigeration apparatus according to claim 1, wherein an ejector is provided as the boosting means.   2. The refrigeration apparatus according to claim 1, wherein an auxiliary compressor is provided as the pressure increasing means.   The gas-liquid separator is provided in the exit side of the said ejector, the refrigerant | coolant which flowed out from the heat exchanger which acts as a condenser is flowed into the said ejector, and the refrigerant | coolant which flowed out of the said ejector is supplied to the said gas-liquid separator. The outdoor decompression device that bypasses a part of the refrigerant that flows in and returns the refrigerant that flows out from the gas side outlet of the gas-liquid separator to the compressor and bypasses part of the refrigerant that flows out from the liquid side outlet of the gas-liquid separator. The main refrigerant on the main stream side of the liquid refrigerant is cooled by the supercooling heat exchanger and sent to the indoor heat exchanger, and the bypass refrigerant gasified by the supercooling heat exchanger is supplied to the ejector. A refrigeration apparatus characterized by being configured to be sucked from an inlet.   In Claim 2, the gas-liquid separator was provided in the exit side of the said ejector, the bypass refrigerant which bypassed a part of refrigerant | coolant from the heat exchanger which acts as a condenser was made to flow in into the said ejector, and it flowed out of the said ejector Refrigerant is allowed to flow into the gas-liquid separator, the refrigerant flowing out from the gas-side outlet of the gas-liquid separator is returned to the compressor, and the refrigerant flowing out from the liquid-side outlet of the gas-liquid separator is The main stream side refrigerant of the refrigerant from the heat exchanger acting as the condenser is decompressed, cooled by the supercooling heat exchanger and sent to the indoor heat exchanger, and gasified by the supercooling heat exchanger The refrigeration apparatus, wherein the bypass refrigerant is sucked from the suction port of the ejector.   4. The outdoor decompression apparatus according to claim 3, further comprising an expander that expands the refrigerant that has flowed out of the heat exchanger acting as a condenser and collects power, and bypasses a part of the refrigerant that has flowed out of the expander. The pressure is reduced by an apparatus and flows into the supercooling heat exchanger, the mainstream refrigerant that is the other of the refrigerant that has flowed out of the expander is cooled and sent to the indoor heat exchanger, and the supercooling heat exchanger The evaporated bypass refrigerant is boosted to a pressure higher than a suction pressure of the compressor and sucked into the compressor by the auxiliary compressor operated by power recovered by the expander. Refrigeration equipment.   4. The apparatus according to claim 3, further comprising an expander that recovers power by decompressing and expanding a bypass refrigerant that bypasses a part of the refrigerant that has flowed out of the heat exchanger that acts as a condenser, and flows out of the heat exchanger that acts as the condenser. The main refrigerant on the other side of the refrigerant that has been cooled is cooled in the supercooling heat exchanger by the bypass refrigerant and sent to the indoor heat exchanger, and the bypass refrigerant evaporated in the supercooling heat exchanger is A refrigeration apparatus characterized in that the auxiliary compressor operated by power recovered by an expander is boosted to a pressure higher than a suction pressure of the compressor and sucked into the compressor.   6. A bridge circuit comprising a check valve according to claim 2, wherein the bridge circuit is used to change the direction of the refrigerant flow path of the ejector and the supercooling heat exchanger. A refrigeration apparatus configured to be in the same direction during both heating operations.   In any one of claims 3, 6, and 7, comprising a bridge circuit constituted by a check valve, using the bridge circuit, the direction of the refrigerant flow path of the auxiliary compressor and the supercooling heat exchanger, A refrigeration apparatus configured to be in the same direction during both cooling and heating operations.   The refrigeration apparatus according to any one of claims 1 to 8, wherein the specific volume of the saturated gas at the same evaporation temperature of the refrigerant used is 1.5 times or more that of R-410A.

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