JP2007298196A - Piping with internal heat exchanger and refrigerating cycle device comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide piping with an internal heat exchanger and a refrigerating cycle device comprising the same, capable of preventing the degradation of cooling performance in accompany with increase in pressure loss in a low-pressure refrigerant piping. <P>SOLUTION: This refrigerating cycle device 100A comprises the internal heat exchanger 160 having a first flow channel 160a and a second flow channel 162, and the piping 170 with the internal heat exchanger having a bypass pipe 171 providing a flow channel joining to an outlet side of the second flow channel 162 while bypassing the internal heat exchanger 160, a refrigerant outflow side of a high-pressure side heat exchanger 120 is connected to an inlet-side connecting portion 164b, refrigerant inflow sides of expansion valves 131, 132 are connected to outlet-side connecting portions 165b, 168b, a refrigerant suction side of a compressor 110 is connected to an outlet-side connecting portion 167a, the refrigerant outflow side of one 141 of two low-pressure side heat exchangers is connected to an inlet-side connecting portion 166a, and the refrigerant outflow side of the other low-pressure side heat exchanger 142 is connected to an inlet-side connecting portion 171a of the bypass pipe 171. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pipe with an internal heat exchanger and a refrigeration cycle apparatus including the same.

  2. Description of the Related Art Conventionally, a refrigeration cycle pipe used for a vehicle air conditioner or the like is known as a pipe provided with an internal heat exchanger. This refrigeration cycle pipe includes, for example, a double pipe as an internal heat exchanger, as shown in Patent Document 1, which includes a high-pressure refrigerant pipe extending from a compressor to a evaporator, and an evaporator. The low-pressure refrigerant pipe extending from the compressor to the compressor is formed as a pipe (double pipe structure) in which at least one part enters the other.

This enables heat exchange between the high-temperature high-pressure refrigerant and the low-temperature low-pressure refrigerant, and the high-pressure refrigerant flowing out of the condenser is supercooled by the low-pressure refrigerant and can be supplied to the evaporator side by increasing the amount of liquid refrigerant. . In the evaporator, as the amount of liquid refrigerant increases, the refrigerant flow resistance decreases and the cooling capacity improves. The low-pressure refrigerant flowing out of the evaporator is overheated by the high-pressure refrigerant so that liquid compression on the compressor can be prevented.
JP 2001-277842 A

  However, for example, in a vehicle air conditioner (a so-called dual air conditioner or the like) having a plurality of evaporators such as front seats and rear seats, the low pressure refrigerant pipes from the two or more evaporators are connected to the low pressure refrigerant of the double pipe portion. When communicating with the pipe, depending on the shape of the double pipe part, there is a problem that the pressure loss in the low-pressure refrigerant pipe increases and the cooling capacity decreases.

  In view of the above problems, an object of the present invention is to provide a pipe with an internal heat exchanger and a refrigeration cycle apparatus including the pipe with an internal heat exchanger that can prevent a decrease in cooling capacity accompanying an increase in pressure loss in the low-pressure refrigerant pipe.

  In order to achieve the above object, the present invention employs the following technical means.

  The invention according to claim 1 includes an internal heat exchanger (160) having a first flow path (160a) and a second flow path (162), which are arranged so as to be able to exchange heat with each other, and internal heat exchange. And a bypass pipe (171) that provides a flow path that bypasses the vessel (160), and the first flow path (160a) is connected to the refrigerant outflow side of the high-pressure heat exchanger (120) at one end thereof. A first inlet side connecting portion (164b) and a first outlet side connecting portion (165b, 168b) connected to the refrigerant inflow side of the expansion valve (131, 132) on the other end side; (162) is connected to the refrigerant outlet side of the low pressure side heat exchanger (141) at one end side thereof, and to the refrigerant suction side of the compressor (110) at the other end side. A second outlet side connecting portion (167a) to be connected, and the bypass pipe (171) is low at one end side thereof. It has a bypass inlet side connection part (171a) connected to the refrigerant outflow side of the side heat exchanger (142), and the other end side of the bypass pipe (171) joins the second outlet side connection part (167a). It is characterized by being connected.

  Such a pipe (170) with an internal heat exchanger can provide a low-pressure path that bypasses the internal heat exchanger (160) by the bypass pipe (171) in the refrigeration cycle apparatus (100A, 200A). It is possible to prevent an increase in pressure loss in the low-pressure piping and prevent a decrease in cooling capacity.

  When the two outlet side connection portions (165b, 168b) are provided as the first outlet side connection portion as in the invention described in claim 2, the refrigeration cycle having two or more expansion valves (131, 132, 233). In the apparatus (100A, 200A), the refrigerant inflow side of at least one expansion valve (131) is connected to one first outlet side connection part (165b), and the refrigerant inflow side of the remaining expansion valves (132, 233) is connected. It can be connected to the other first outlet side connecting portion (168b).

  In the pipe with internal heat exchanger (170), as in the invention according to claim 3, the double pipe portion (160) formed by inserting the inner pipe (162) into the outer pipe (161). An internal heat exchanger (160) is configured, and one of the first flow path (160a) and the second flow path (162) is connected between the outer pipe (161) and the inner pipe (162). The other channel can be formed as a channel in the inner pipe (162).

  At this time, as in the invention described in claim 4, when the total bending angle obtained by adding the bending angles of one or more bending portions (163b) of the double pipe portion (160) is 160 degrees or more, When the length of the double pipe part (160) is 600 mm or more as in the invention described in claim 5, the pressure loss in the low pressure path of the refrigeration cycle (100A, 200A) increases, and the cooling capacity is increased. There is a tendency to decrease. In the pipe with internal heat exchanger (170), a low-pressure path that bypasses the double pipe part (160) can be provided by the bypass pipe (171), so that a reduction in cooling capacity can be reduced.

  In this case, as in the invention described in claim 6, the first flow path (160a) is formed as a flow path between the outer pipe (161) and the inner pipe (162), and the second flow path (162). Is formed as a flow path in the inner pipe (162), the low-pressure refrigerant in the inner pipe (162) is covered by the outer pipe (161), so the outer periphery of the double pipe portion (160) is hot. Even in some cases, the low-pressure refrigerant can be prevented from receiving heat from the outside.

  In the double pipe portion (160), when the groove portion is formed on the outer surface of the inner pipe (162), the flow between the inner pipe (162) and the outer pipe (161) is formed. Since the path is enlarged and the surface area of the inner pipe (162) is increased, the heat exchange efficiency between the high-pressure refrigerant and the low-pressure refrigerant can be improved.

  In the invention described in claim 8, the compressor (110), the high-pressure side heat exchanger (120), the expansion valves (131, 132, 233) and the low-pressure side heat exchanger (Parallel) arranged in parallel as a pair. 141, 142, 243), the internal heat exchanger pipe (170) according to any one of claims 1 to 7, wherein the refrigerant of the high pressure side heat exchanger (120) is provided. The outflow side is connected to the first inlet side connection part (164b), the refrigerant inflow side of the expansion valves (131, 132, 233) is connected to the first outlet side connection part (165b, 168b), and at least one of the plurality of sets The refrigerant outflow side of the low pressure side heat exchanger (141) is connected to the second inlet side connection portion (166a), and the refrigerant outflow side of the remaining low pressure side heat exchangers (142, 243) is connected to the bypass inlet side connection portion ( 171a) Is, the refrigerant suction side of the compressor (110) is characterized in that it is connected to the second outlet-side connecting portion (167a).

  Thereby, in the refrigeration cycle apparatus (100A, 200A) having a plurality of low-pressure side heat exchangers (141, 142, 243), a part of the plurality of low-pressure side heat exchangers (141, 142, 243) Since the low-pressure refrigerant can be circulated through the bypass pipe (171) and the internal heat exchanger (160) can be bypassed, an increase in pressure loss in the low-pressure pipe can be prevented and a reduction in cooling capacity can be prevented.

  When the refrigeration cycle apparatus (100A) includes two low-pressure side heat exchangers (141, 142), the refrigerant outflow side of one low-pressure side heat exchanger (141) as in the invention according to claim 9. Is connected to the second inlet side connecting portion (166a), and the refrigerant outlet side of the other low pressure side heat exchanger (142) is connected to the bypass inlet side connecting portion (171a).

  When the refrigeration cycle apparatus (200A) includes three low-pressure side heat exchangers (141, 142, 243), one low-pressure side heat exchanger (141) as in the invention described in claim 10. It is preferable to connect the refrigerant outflow side to the second inlet side connecting portion (166a) and connect the refrigerant outflow side of the other two low pressure side heat exchangers (142, 243) to the bypass inlet side connecting portion (171a).

  When the pipe with heat exchanger (170) includes two outlet side connection portions (165b, 168b) as the first outlet side connection portion as in the invention described in claim 11, a plurality of sets of expansions are provided. The refrigerant inflow side of at least one set of expansion valves (131) of the valves is connected to one first outlet side connection part (165b), and the refrigerant inflow side of the remaining sets of expansion valves (132, 233) is connected to the other side. To the first outlet side connecting portion (168b).

  The refrigeration cycle apparatus of the present invention is suitably applied to a vehicle as in the invention described in claim 12. As the refrigerant, HFC134a may be used as in the invention described in claim 13.

  Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with the specific means described in the embodiments described later.

(First embodiment)
In the present embodiment, the pipe 170 with an internal heat exchanger and the refrigeration cycle apparatus 100A using the pipe 170 according to the present invention are applied to a vehicle air conditioner (hereinafter, air conditioner) 100. Hereinafter, a specific configuration will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic configuration diagram illustrating the entire air conditioner 100, and FIG. 2 is a schematic diagram illustrating the entire configuration of a pipe 170 with an internal heat exchanger.

  As shown in FIG. 1, the vehicle is divided into an engine room 1 in which a traveling engine 10 is mounted and a passenger compartment 2 by a dash panel 3, and a refrigeration cycle apparatus constituting an air conditioner 100. Among the 100A and the indoor units 100B and 100C, the refrigeration cycle apparatus 100A (excluding the expansion valves 131 and 132 and the evaporators 141 and 142 as low-pressure side heat exchangers) is disposed in the engine room 1. The air conditioner 100 in the present embodiment is a so-called dual air conditioner that includes two indoor units 100B and 100C for the front seat and the rear seat, and the front seat indoor unit 100B is disposed in the instrument panel of the passenger compartment 2. The rear seat indoor unit 100C is disposed between the rear side body of the passenger compartment 2 and the interior panel.

  The front seat indoor unit 100 </ b> B is a unit formed by arranging the blower 102, the evaporator 141, the heater core 103, and the like in the air conditioning case 101. The blower 102 selectively takes in outside air or inside air of the vehicle as conditioned air and blows the conditioned air to the evaporator 141 and the heater core 103. The evaporator 141 is a heat exchanger for cooling that evaporates a refrigerant accompanying operation of a refrigeration cycle apparatus 100A described later and cools conditioned air by latent heat of evaporation at that time. The heater core 103 is a heat exchanger for heating that heats conditioned air using hot water of the engine 10 as a heating source.

  An air mix door 104 is provided in the air conditioning case 101 in the vicinity of the heater core 103. The air mix door 104 is heated by the heater core 103 and the conditioned air cooled by the evaporator 141 according to the opening degree of the air mix door 104. The mixing ratio with the conditioned air is varied and adjusted to the temperature set by the passenger.

  On the other hand, the rear seat indoor unit 100 </ b> C is a unit formed by arranging the blower 109, the evaporator 142, and the like in the air conditioning case 108. The blower 109 takes in the inside air of the vehicle as conditioned air and blows the conditioned air to the evaporator 142. The evaporator 142 is a heat exchanger for cooling that evaporates a refrigerant accompanying the operation of the refrigeration cycle apparatus 100A described later and cools the conditioned air by latent heat of evaporation at that time. In the present embodiment, the rear seat indoor unit 100C does not include the heater core 103, the air mix door 104, and the like that the front seat indoor unit 100B has.

  The refrigeration cycle apparatus 100A includes a compressor 110, a condenser 120 as a high-pressure side heat exchanger, expansion valves 131 and 132, and the evaporators 141 and 142, which are sequentially connected by a pipe 150 to form a closed circuit. In the middle of the pipe 150, the pipe 170 with an internal heat exchanger according to the embodiment of the present invention is provided. The condenser 120 is a high-pressure side heat exchanger, and is also called a radiator or a gas cooler. The evaporators 141 and 142 are low-pressure side heat exchangers and are also called coolers or heat absorbers. The expansion valves 131 and 132 are pressure reducers, and may be provided by a throttle, a valve, an ejector, or the like. In the refrigeration cycle apparatus 100A of the present embodiment, HFC134a is used as the refrigerant.

  The compressor 110 is a fluid device that compresses the refrigerant in the refrigeration cycle apparatus 100 </ b> A to a high temperature and a high pressure, and is driven by the driving force of the engine 10 here. That is, the pulley 111 is fixed to the drive shaft of the compressor 110, and the driving force of the engine 10 is transmitted to the pulley 111 via the crank pulley 11 and the drive belt 12, and the compressor 110 is driven. The pulley 111 is provided with an electromagnetic clutch (not shown) that connects and disconnects between the compressor drive shaft and the pulley 111. The condenser 120 is a heat exchanger that is connected to the discharge side of the compressor 110 and condenses and liquefies the refrigerant by exchanging heat with the outside air.

  The expansion valve (hereinafter referred to as the front expansion valve) 131 and the expansion valve (hereinafter referred to as the rear expansion valve) 132 are valves that decompress and expand the liquid-phase refrigerant flowing out of the condenser 120 to reduce the pressure in an isoenthalpy manner. They are provided on the indoor units 100B and 100C side in contact with the evaporators 141 and 142, respectively. The expansion valves 131 and 132 are temperature type expansion valves that control the throttle opening so that the degree of superheat of the refrigerant flowing out of the evaporators 141 and 142 (the refrigerant sucked into the compressor 110) becomes a predetermined value. The evaporators 141 and 142 are cooling heat exchangers that cool the conditioned air as described above, and the refrigerant outlet sides of the evaporators 141 and 142 are connected to the suction side of the compressor 110.

  As shown in FIG. 2, the pipe 170 with an internal heat exchanger includes a double pipe portion 160 and a bypass pipe 171. , 132, a high-pressure pipe 151 through which a high-temperature high-pressure refrigerant from the compressor 110 flows, and a low-temperature low-pressure refrigerant between the evaporator (hereinafter referred to as front evaporator) 141 of the front seat air conditioning unit 100B and the compressor 110. At least a part of the flowing low-pressure pipe 152 forms a double pipe structure.

  Further, the bypass pipe 171 includes a part of the low-pressure pipe 152 in the pipe 150 in which low-temperature low-pressure refrigerant flows between the evaporator (hereinafter, rear evaporator) 142 of the rear seat air conditioning unit 100 </ b> C and the compressor 110. Thus, the low-pressure refrigerant from the rear evaporator 142 bypasses the double pipe portion (heat exchanger) 160 and reaches the compressor 110.

  Hereinafter, the details of the pipe 170 with the internal heat exchanger will be described with reference to FIGS. 3 and 4. FIG. 3 shows the appearance of the pipe 170 with the internal heat exchanger, and FIG. 4 is a cross-sectional view showing the IV part in FIG. The double pipe portion 160 has a total length (points A to B in FIG. 3) of about 600 mm, and is opposed to the straight pipe portion 163a that extends straight in order to avoid interference with the engine 10 and other devices, bodies, and the like. A plurality of (two in the present embodiment) bent portions 163 b are formed and mounted in the engine room 1. Here, the bending portion angle of the bending portion 163b is an angle with respect to the straight pipe portion 163a (α, β in FIG. 3), and the total angle of each bending portion 163b is the total bending angle (in FIG. 3). α + β). The total bending angle of the double pipe portion 160 in this embodiment is about 160 degrees.

  The double pipe portion 160 includes an outer pipe (corresponding to the outer pipe in the present invention) 161 and an inner pipe (corresponding to the inner pipe in the present invention) 162 formed individually, and the inside of the outer pipe 161 is the inner pipe. 162 is arranged to penetrate therethrough. The outer tube 161 is, for example, an aluminum φ22 mm tube, and the inner tube 162 is, for example, an aluminum φ19.1 mm tube. After both ends of the outer tube 161 are combined with the inner tube 162, the entire circumference thereof is contracted radially inward and welded to the circumferential surface of the inner tube 162 so as to be airtight or liquid tight. ing. Therefore, a space is formed between the outer tube 161 and the inner tube 162, and this space serves as an inner / outer flow path 160a.

  Aluminum pipes 164 and 165 made of aluminum forming the high-pressure pipe 151 are connected to the circumferential wall surface on both end sides (points A and B in FIG. 3) of the outer pipe 161 and the outer and inner passages 160a are communicated. Is brazed. The liquid pipe 164 has at least one bent portion and extends toward the condenser 120, and a joint 164b as a connecting portion is provided at the tip. The liquid pipe 165 has at least one bent portion and extends toward the front expansion valve 131, and a joint 165b is provided at the tip.

  Further, the liquid pipe 165 branches at a longitudinal intermediate point (in the present embodiment, a middle point shown by C in FIG. 3), and here, a liquid pipe 168 made of aluminum using a three-way branch connector 169. Is connected. The liquid pipe 168 has at least one bent portion and extends toward the rear expansion valve 132, and a joint 168b is provided at the tip. The joint 164b is connected to the refrigerant outflow side of the condenser 120, the joint 165b is connected to the refrigerant inflow side of the front side expansion valve 131, and the joint 168b is connected to the refrigerant inflow side of the rear side expansion valve 132. As a result, high-pressure refrigerant flows through the liquid pipe 164, the inner and outer flow paths 160a, and the liquid pipes 165 and 168.

  On the other hand, an aluminum suction pipe 166 forming a low pressure pipe 152 is provided at an end of the inner pipe 162 on the liquid pipe 165 side, and a joint 166a is provided at the tip of the suction pipe 166. A joint 167a is provided at the end of the inner pipe 162 on the liquid pipe 164 side.

  In addition, a bypass communicating with the inside of the inner pipe 162 is provided at an intermediate point between the weld position of the outer pipe 161 and the joint 167a at the end of the inner pipe 162 (in the present embodiment, a middle point indicated by D in FIG. 3). A tube 171 is connected. The bypass pipe 171 is, for example, a φ12.7 mm pipe made of aluminum, and is connected to the inner pipe 162 in a T shape by brazing. The bypass pipe 171 has at least one bent portion and extends toward the rear evaporator 142, and a joint 171a is provided at the tip thereof.

  The joint 166a is connected to the refrigerant outflow side of the front evaporator 141, the joint 167a is connected to the refrigerant intake side of the compressor 110, and the joint 171a is connected to the refrigerant outflow side of the rear evaporator 142. As a result, the low-pressure refrigerant flows through the suction pipe 166, the bypass pipe 171, and the inner pipe 162.

  A circumferential groove 162c and a spiral groove 162a are provided on the surface of the inner tube 162 corresponding to the region where the inner-outer flow path 160a is formed. The circumferential groove 162c is a groove extending in the circumferential direction of the inner tube 162 provided corresponding to the position of the connection portion of each liquid pipe 164, 165 with the outer tube 161. Further, the spiral groove 162a is a multiple groove that is connected to each of the circular grooves 162c and extends spirally in the longitudinal direction of the inner tube 162 between both the circular grooves 162c. Between the spiral groove portions 162a, a ridge portion 162b is formed in which the outer diameter of the inner tube 162 is substantially maintained (strictly, the tube is contracted). The circumferential groove portion 162c and the spiral groove portion 162a correspond to the groove portions in the present invention. The groove portions 162c and 162a expand the inner / outer flow path 160a, and the surface area of the inner pipe 162 is increased. The efficiency of heat exchange with the refrigerant is improved. The circumferential groove 162c and the spiral groove 162a can be formed by a grooving tool, for example.

  The inner / outer flow path 160a in the present embodiment corresponds to the first flow path in the present invention, and the inner tube 162 corresponds to the second flow path in the present invention. Further, the joint 164b corresponds to the first inlet side connection portion in the present invention, the joint 165b corresponds to the first outlet side connection portion in the present invention, and the joint 168b corresponds to the first outlet side connection portion in the present invention. It corresponds to. The joint 166a corresponds to the second inlet side connection portion in the present invention, and the joint 167a corresponds to the second outlet side connection portion in the present invention. The joint 171a corresponds to the bypass inlet side connecting portion in the present invention.

  The joint device as the connecting portion in this embodiment refers to a device that can be attached and detached by an operator's operation, such as a joint device that can be tightened by a bolt or a nut, or a quick joint device having an engaging claw member. The joint device in this embodiment is a device that provides passage communication without requiring high temperature or flame-related connection operations such as brazing or welding. The joint device used at the location shown in this embodiment allows the piping 170 to be installed, removed and replaced in the market. In this embodiment, since the piping parts including the internal heat exchanger and the bypass pipe are provided as one piece as a whole, the connection between the bypass pipe 171 and the inner pipe 162 uses a flame like brazing. Provided by connection work. However, the connection between the bypass pipe 171 and the inner pipe 162 may be provided by a detachable joint device such as a bolt or a nut.

  Next, the operation based on the above configuration and the operation and effect thereof will be described with reference to FIGS. FIG. 5 is a schematic diagram showing the configuration of the refrigeration cycle apparatus 100A, and FIG. 6 is a Mollier diagram.

  When there is an air conditioning request from an occupant, for example, a cooling request, the electromagnetic clutch of the compressor 110 is connected, the compressor 110 is driven by the engine 10, sucks and compresses refrigerant from the evaporators 141 and 142 side, The high pressure refrigerant is discharged to the condenser 120 side. The high-pressure refrigerant is cooled and condensed and liquefied in the condenser 120. The refrigerant here is almost in a liquid phase.

  The condensed and liquefied refrigerant passes from the liquid pipe 164 of the double pipe section 160 through the inner / outer flow path 160a to the front expansion valve 131 via the liquid pipe 165, and is also split at the point C from the liquid pipe 165. It reaches the rear expansion valve 132 via the pipe 168. The refrigerant is decompressed and expanded in the expansion valves 131 and 132 and evaporated in the evaporators 141 and 142. In the evaporators 141 and 142, the conditioned air is cooled as the refrigerant evaporates.

  Then, the saturated gas refrigerant evaporated in the front evaporator 141 flows through the inner pipe 162 from the suction pipe 166 of the double pipe section 160 as a low-temperature low-pressure refrigerant and returns to the compressor 110. On the other hand, the saturated gas refrigerant from the rear evaporator 142 joins the inner pipe 162 at the point D via the bypass pipe 171 and returns to the compressor 110. In this way, the saturated gas refrigerant from the rear evaporator 142 bypasses the double pipe portion (internal heat exchanger) 160.

  Here, in the double pipe portion 160, heat exchange is performed between the high-pressure refrigerant and the low-pressure refrigerant, the high-pressure refrigerant is cooled, and the low-pressure refrigerant is heated. That is, the liquid-phase refrigerant that has flowed out of the condenser 120 is further supercooled by the double pipe portion 160, and the temperature reduction is promoted. The saturated gas refrigerant that has flowed out of the front evaporator 141 is further heated by the double pipe portion 160 to become a gas refrigerant having a superheat degree.

  As described above, in the present embodiment, only the low-pressure refrigerant from the front evaporator 141 among the low-pressure refrigerants from the front and rear evaporators 141 and 142 to the compressor 110 is the double pipe portion (internal heat). Since the low-pressure refrigerant from the rear evaporator 142 bypasses the double pipe 160 and reaches the compressor 110, the low-pressure refrigerant from both the evaporators 141 and 142 is used together. Compared with the case where it circulates through the double pipe section 160, it is possible to prevent an increase in pressure loss in the low-pressure pipe 152 and the inner pipe 162 and to prevent a decrease in cooling capacity in the refrigeration cycle apparatus 100A. Moreover, since the heat exchange amount in the double pipe part 160 can also be reduced, the temperature rise of a low-pressure refrigerant | coolant can be suppressed. Therefore, the rise in the internal temperature and the discharge temperature in the compressor 110 can be suppressed, and deterioration in the durability of the compressor 110 parts due to heat can be prevented.

  For example, when the flow rate of the low-pressure refrigerant from the front evaporator 141 is 100 kg / h and the flow rate of the low-pressure refrigerant from the rear evaporator 142 is 50 kg / h, when both are circulated through the double pipe portion 160, While the pressure loss in the double pipe section 160 is 30 kPa, the heat exchange amount is 800 W, and the discharge temperature in the compressor 110 is 105 degrees, the low-pressure refrigerant from the rear evaporator 142 bypasses the double pipe section 160. As a result, it was confirmed that the pressure loss in the double pipe portion 160 was reduced to 20 kPa, the heat exchange amount was 600 W, and the discharge temperature in the compressor 110 was reduced to 100 degrees.

  Moreover, although the bending total angle of the double pipe part 160 in this embodiment was about 160 degrees, as shown in FIG. 7, when the bending total angle of the double pipe part 160 is 160 degrees or more, By adopting the pipe 170 with an internal heat exchanger according to the present invention and configuring so that the low-pressure refrigerant from the rear evaporator 142 bypasses the double pipe portion 160, cooling is achieved as compared with the case where the bypass is not bypassed. Ability improves. When the total bending angle of the double pipe portion 160 is relatively large, the linear distance between the points A and B of the double pipe portion 160 is shortened, and the length of the bypass pipe 171 that bypasses the double pipe portion 160 is long. Since the length can be shortened, the bypass pipe 171 can be easily disposed in the engine room 1.

  FIG. 8 shows the relationship between the length of the double pipe section 160, the heat exchange amount in the double pipe section 160, the pressure loss in the low pressure pipe 152 and the inner pipe 162, and the cooling capacity of the refrigeration cycle apparatus 100A. 14 is a graph showing a comparison between a case where the low-pressure refrigerant from 142 bypasses the double pipe section 160 and a case where the low-pressure refrigerant bypasses the double pipe section 160. According to this, as the length of the double pipe part 160 becomes longer, it can be seen that the cooling capacity decreases as the pressure loss increases from nearing 600 mm. In the present embodiment, the length of the double pipe portion 160 is 600 mm. However, when the length of the double pipe portion 160 is relatively long and is 600 mm or more, the internal heat exchange of the present invention is performed. By adopting the pipe 170 with the cooler and by configuring so that the low-pressure refrigerant from the rear evaporator 142 bypasses the double pipe section 160, it is possible to suppress the pressure loss and reduce the cooling capacity.

  In the present embodiment, since the high-pressure refrigerant is circulated through the inner-outer flow path 160a and the low-pressure refrigerant is circulated through the inner pipe 162, the inner pipe 162 through which the low-pressure refrigerant circulates is covered with the outer pipe 161. There is no concern that radiant heat from the engine 10 or the like is received by the low-pressure refrigerant in the inner pipe 162.

(Second Embodiment)
A second embodiment of the present invention is shown in FIG. In the first embodiment, the pipe 170 with the internal heat exchanger of the present invention is attached to the refrigeration cycle 100A of the vehicle air conditioner (dual air conditioner) 100 including the two evaporators 141 and 142 for the front seat and the rear seat. In contrast to the application, in the present embodiment, the refrigeration cycle of a vehicle air conditioner (triple air conditioner) including three evaporators 141, 142, and 243 for front seats and rear seats, and further for a cool box. The pipe 170 with an internal heat exchanger of the present invention is applied to 200A.

  A pipe 170 with an internal heat exchanger in the present embodiment has the same configuration as that of the first embodiment shown in FIGS. 2 to 4, and includes a condenser 120, a compressor 110, a front expansion valve 131, and a front evaporator. 141 are connected to joints 164b, 167a, 165b, 166a, respectively. A pipe 250 constituting a high-pressure pipe 151 leading to the rear expansion valve 132 is connected to the joint 168b at the tip of the liquid pipe 168. This pipe branches at point E shown in FIG. It is connected to the expansion valve 233 on the cool box evaporator 243 side. Thus, the high-pressure refrigerant flowing out from the liquid pipe 168 reaches the rear side expansion valve 132 and the expansion valve 233 on the cool box evaporator 243 side through the pipes 250 and 251.

  The joint 171a at the tip of the bypass pipe 171 is connected to a pipe 253 that forms a low-pressure pipe 152 from the rear evaporator 142. The pipe 253 is connected to the low-pressure pipe 152 from the cool box evaporator 243. The formed piping 254 joins at the point F shown in FIG. As a result, low-pressure refrigerant from the rear evaporator 142 and the cool box evaporator 243 flows into the bypass pipe 171. The other structure of the vehicle air conditioner in this embodiment is the same as that of the said 1st Embodiment.

  In the case of a vehicle air conditioner including three evaporators 141, 142, and 243 as described above, when all the low-pressure refrigerant from the three evaporators 141, 142, and 243 is circulated to the double pipe portion 160, the low-pressure pipe 152 Since the pressure loss in the refrigerant increases and the cooling capacity decreases, the front side of the low-pressure refrigerant from the evaporators 141, 142, and 243 for the front side, the rear side, and the cool box to the compressor 110 as in the present embodiment. Only the low-pressure refrigerant from the evaporator 141 is circulated to the double pipe part (heat exchanger) 160, and the low-pressure refrigerant from the rear evaporator 142 and the cool box evaporator 243 bypasses the double pipe part 160 and is a compressor. By being configured to reach 110, an increase in pressure loss in the low-pressure pipe 152 can be prevented, and a decrease in cooling capacity can be prevented. Moreover, since the amount of heat exchange in the double pipe portion 160 is also reduced, it is possible to suppress an increase in internal temperature and discharge temperature in the compressor 110 and to prevent a decrease in durability of the compressor 110 parts due to heat.

(Other embodiments)
In the second embodiment, the low-pressure refrigerant from the front evaporator 141 is circulated to the double pipe section 160, and the low-pressure refrigerant from the rear evaporator 142 and the cool box evaporator 243 bypasses the double pipe section 160. However, the present invention is not limited to this. For example, the low-pressure refrigerant from the front evaporator 141 and the cool box evaporator 243 is circulated through the double pipe portion 160, and only the low-pressure refrigerant from the rear evaporator 142 is supplied. The heavy pipe portion 160 may be bypassed.

  The spiral groove 162a of the inner tube 162 in each of the above embodiments is not limited to this, and any configuration that can improve the heat exchange efficiency between the high-pressure refrigerant and the low-pressure refrigerant, for example, extends in the longitudinal direction of the inner tube 162. It is good also as a straight groove part.

  In each of the above embodiments, the outer tube 161, the inner tube 162, and the bypass tube 171 are made of aluminum. However, the present invention is not limited to this, and may be made of iron or copper. In addition, the double pipe portion 160 has a configuration including an outer tube 161 and an inner tube 162 that are individually formed. Instead, the outer tube 161 and the inner tube 162 have a connecting portion and are simultaneously formed. It is good also as the extrusion double tube formed.

  In each of the above-described embodiments, the internal heat exchanger 160 is configured as a double tube including the outer tube 161 and the inner tube 162. However, the present invention is not limited thereto, and may be configured with a parallel tube or the like.

  Further, the liquid pipes 164, 165, 168 and the bypass pipe 171 may be straight pipes when there is no particular problem in assembling with the counterpart side.

  In each said embodiment, although the pipe 170 with an internal heat exchanger of this invention was applied to the vehicle air conditioner 100, you may apply not only to this but to a household air conditioner. When the internal heat exchanger is configured as the double pipe portion 160 in a home air conditioner, the outside air temperature of the outer pipe 161 can be used under a lower condition than in the case of the engine room 1 used for a vehicle. Depending on the heat exchange performance between the high-pressure refrigerant and the low-pressure refrigerant, the low-pressure refrigerant may be circulated through the inner-outer flow path 160 a and the high-pressure refrigerant may be circulated through the inner pipe 162.

  The piping in this embodiment can also be applied to a supercritical refrigeration cycle using carbon dioxide as a refrigerant, for example. In the supercritical refrigeration cycle apparatus, the high-pressure side heat exchanger is called a radiator and the expansion valve is also called a pressure control valve.

It is a schematic block diagram which shows the whole vehicle air conditioner in 1st Embodiment. It is a schematic diagram which shows the structure of piping with an internal heat exchanger in 1st Embodiment. It is an external view which shows the whole piping with an internal heat exchanger in 1st Embodiment. FIG. 4 is a transverse sectional view showing a IV part in FIG. 3. It is a schematic diagram which shows the structure of the refrigeration cycle apparatus in 1st Embodiment. It is a graph which shows the Mollier diagram of a refrigeration cycle apparatus. It is a graph which shows the relationship between the bending total angle of a double pipe part, and cooling capacity. It is a graph which shows the relationship of the amount of heat exchange, pressure loss, and cooling capacity with respect to the length of a double pipe part. It is a schematic diagram which shows the structure of the refrigeration cycle apparatus in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Vehicle air conditioner 100A, 200A Refrigeration cycle apparatus 110 Compressor 120 Condenser (high-pressure side heat exchanger)
131 Front expansion valve (expansion valve)
132 Rear expansion valve (expansion valve)
141 Front evaporator (low pressure side heat exchanger)
142 Rear evaporator (low pressure side heat exchanger)
160 Double pipe (internal heat exchanger)
160a Internal / external flow path (first flow path)
161 Outer pipe (outer pipe)
162 Inner pipe (second flow path, inner pipe)
162a Spiral groove (groove)
162c Circumferential groove (groove)
163b Bending part 164b Joint (first inlet side connecting part)
165b Joint (first outlet side connection part)
166a Joint (second inlet side connection part)
167a Joint (second outlet side connection part)
168b Joint (first outlet side connection)
171 Bypass pipe 171a Joint (Bypass inlet side connection part)
233 Expansion valve 243 Cool box evaporator (low pressure side heat exchanger)

Claims (13)

An internal heat exchanger (160) having a first flow path (160a) and a second flow path (162), which are arranged to exchange heat with each other;
A bypass pipe (171) providing a flow path bypassing the internal heat exchanger (160),
The first flow path (160a) has a first inlet side connection (164b) connected to the refrigerant outflow side of the high pressure side heat exchanger (120) at one end side thereof, and an expansion valve (131, 132) having a first outlet side connecting portion (165b, 168b) connected to the refrigerant inflow side,
The second flow path (162) has a second inlet side connecting portion (166a) connected to the refrigerant outflow side of the low pressure side heat exchanger (141) at one end side, and a compressor (110) at the other end side. A second outlet side connection portion (167a) connected to the refrigerant suction side of
The bypass pipe (171) has a bypass inlet side connection part (171a) connected to the refrigerant outflow side of the low pressure side heat exchanger (142) at one end side thereof,
A pipe with an internal heat exchanger, wherein the other end side of the bypass pipe (171) is connected so as to join the second outlet side connection part (167a).   2. The pipe with an internal heat exchanger according to claim 1, comprising two outlet side connection portions (165 b, 168 b) as the first outlet side connection portion. The internal heat exchanger (160) is a double pipe part (160) formed by inserting the inner pipe (162) into the outer pipe (161),
One of the first flow path (160a) and the second flow path (162) is formed as a flow path between the outer pipe (161) and the inner pipe (162), The pipe with an internal heat exchanger according to claim 1 or 2, wherein the other flow path is formed as a flow path in the inner pipe (162). The double pipe portion (160) has one or more bent portions (163b),
The pipe with an internal heat exchanger according to claim 3, wherein a total bending angle obtained by adding the bending angles of the bent portions (163b) is 160 degrees or more.   The pipe with an internal heat exchanger according to claim 3 or 4, wherein a length of the double pipe portion (160) is 600 mm or more.   The first flow path (160a) is formed as a flow path between the outer pipe (161) and the inner pipe (162), and the second flow path (162) is formed in the inner pipe (162). The pipe with an internal heat exchanger according to any one of claims 3 to 5, wherein the pipe is formed as a flow path.   The internal heat exchange according to any one of claims 3 to 6, wherein a groove (162a) is formed in an outer surface of the inner pipe (162) in the double pipe portion (160). With piping. Refrigeration having a compressor (110), a high pressure side heat exchanger (120), a plurality of pairs of expansion valves (131, 132, 233) arranged in parallel and a low pressure side heat exchanger (141, 142, 243) In cycle equipment,
A pipe with an internal heat exchanger (170) according to any one of claims 1 to 7,
The refrigerant outflow side of the high-pressure side heat exchanger (120) is connected to the first inlet side connection portion (164b),
The refrigerant inflow side of the expansion valve (131, 132, 233) is connected to the first outlet side connection portion (165b, 168b),
The refrigerant outflow side of at least one low pressure side heat exchanger (141) of the plurality of sets is connected to the second inlet side connection portion (166a),
The refrigerant outflow side of the remaining set of low pressure side heat exchangers (142, 243) is connected to the bypass inlet side connection portion (171a),
A refrigeration cycle apparatus, wherein a refrigerant suction side of the compressor (110) is connected to the second outlet side connection portion (167a).   Two low-pressure side heat exchangers (141, 142) are provided as the plurality of sets of low-pressure side heat exchangers, and the refrigerant outflow side of one of the low-pressure side heat exchangers (141) is the second inlet-side connection portion (166a). The refrigeration cycle apparatus according to claim 8, wherein the refrigerant outlet side of the other low-pressure side heat exchanger (142) is connected to the bypass inlet side connection portion (171a).   The low pressure side heat exchangers (141, 142, 243) are provided as the plurality of sets of low pressure side heat exchangers, and the refrigerant outflow side of one low pressure side heat exchanger (141) is connected to the second inlet side connection portion ( The refrigerant outflow side of the remaining two low-pressure side heat exchangers (142, 243) is connected to the bypass inlet side connection portion (171a). Refrigeration cycle equipment. The first outlet side connecting portion includes two outlet side connecting portions (165b, 168b),
The refrigerant inflow side of at least one of the plurality of sets of expansion valves (131) is connected to one of the first outlet side connection portions (165b), and the refrigerant inflow side of the remaining sets of expansion valves (132, 233) The refrigeration cycle apparatus according to any one of claims 8 to 10, wherein the refrigeration cycle apparatus is connected to the other second outlet side connection portion (168b).   The refrigeration cycle apparatus according to any one of claims 8 to 11, wherein the refrigeration cycle apparatus is applied to a vehicle.   The refrigeration cycle apparatus according to any one of claims 8 to 12, wherein HFC134a is used as the refrigerant.

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