JP3625803B2 - Refrigerant circuit using CO2 refrigerant - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigerant circuit including a compressor and a gas cooler and using a CO ₂ refrigerant.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, a car air conditioner that air-conditions a passenger compartment of a car has a refrigerant circuit in which a compressor such as a rotary compressor, a gas cooler, a pressure reducing device, an evaporator, and the like are sequentially connected in an annular manner. Then, the high-temperature and high-pressure refrigerant discharged from the compressor is radiated by a gas cooler, depressurized by a decompression device, and then flows into the evaporator to evaporate. The vehicle interior is air-conditioned by the endothermic action generated in the evaporator. It was a thing.
[0003]
[Problems to be solved by the invention]
Here, the gas cooler is composed of a fin-and-tube or microtube heat exchanger composed of a normal refrigerant pipe and a heat radiation fin attached to the heat exchanger. A continuous refrigerant stream is used from upstream to downstream.
[0004]
On the other hand, in recent years, in order to cope with the global environmental problem, it has been attempted to use CO ₂ (carbon dioxide), which is a natural refrigerant, as a refrigerant in a refrigerant circuit such as this type of car air conditioner without using a conventional chlorofluorocarbon refrigerant. However, since the CO2 refrigerant is used at the critical point, the temperature change in the gas cooler becomes remarkable.
[0005]
That is, in the case of a normal refrigerant, the temperature rapidly decreases immediately after entering the gas cooler and becomes a condensing temperature and hardly changes thereafter. However, in the case of a CO ₂ refrigerant, upstream of the refrigerant flow in the gas cooler. The temperature begins to decrease over the entire range from the downstream to the downstream.
[0006]
From this situation, if the heat dissipating fins of the gas cooler are continuous from the upstream to the downstream of the refrigerant flow in the refrigerant circuit using the CO2 refrigerant, the heat of the portion located on the upstream side will flow to the downstream side. There has been a problem in that the heat that has been transmitted to the portion located and the temperature of the refrigerant has been lowered on the downstream side is affected by the heat that has traveled through the heat dissipating fins, resulting in a decrease in the heat dissipating efficiency of the gas cooler.
[0007]
The present invention has been made to solve the conventional technical problem, and an object thereof is to improve the heat radiation efficiency in the gas cooler of the refrigerant circuit using the CO2 refrigerant.
[0008]
[Means for Solving the Problems]
That is, the refrigerant circuit of the present invention includes a compressor and a gas cooler, and dissipates the CO ₂ refrigerant discharged from the compressor with the gas cooler, and the gas cooler is exchanged heat with the refrigerant pipe and the refrigerant pipe, respectively. The heat exchanger is composed of a plurality of heat exchangers attached to the heat exchanger, and each heat exchanger is connected in series with the refrigerant flow so that the heat dissipating fins of the adjacent heat exchangers are separated from each other. It is characterized by being arranged.
[0009]
According to the present invention, in a refrigerant circuit that includes a compressor and a gas cooler and dissipates the CO ₂ refrigerant discharged from the compressor with the gas cooler, the gas cooler is attached to the refrigerant pipe and the refrigerant pipe in a heat exchange manner. Since it is composed of a plurality of heat exchangers composed of heat radiation fins, each heat exchanger is connected in series with the flow of the refrigerant, and the heat radiation fins of the adjacent heat exchangers are arranged so as to be separated from each other. In the flow of the refrigerant in the gas cooler, it is possible to prevent or suppress the disadvantage that the heat of the radiating fin of the heat exchanger located on the upstream side is transmitted to the radiating fin of the heat exchanger located on the downstream side Become.
[0010]
Accordingly, CO ₂ refrigerant temperature flowing through the heat exchanger located on the downstream side is reduced, eliminate a disadvantage that the temperature rise by the heat of the heat exchanger located on the upstream side, or suppressing, the CO ₂ refrigerant The heat radiation efficiency in the gas cooler of the refrigerant circuit used can be remarkably improved.
[0011]
In the refrigerant circuit using the CO ₂ refrigerant of the present invention, the interval between the heat dissipating fins of the heat exchangers adjacent to each other on the upstream side of the refrigerant flow is set so that the heat exchange adjacent to each other on the downstream side of the refrigerant flow is performed. It is characterized by being larger than the interval between the heat dissipating fins of the vessel.
[0012]
Thereby, in addition to the above, the interval between the heat dissipating fins of the heat exchangers adjacent to each other on the upstream side of the refrigerant flow is larger than the interval between the heat dissipating fins of the heat exchangers adjacent to each other on the downstream side of the refrigerant flow. Therefore, heat conduction from the upstream heat exchanger to the downstream heat exchanger is effective while minimizing the expansion of the overall size of the gas cooler caused by providing a space between the heat radiation fins of each heat exchanger. It can be prevented or suppressed.
[0013]
In the refrigerant circuit using the CO ₂ refrigerant according to the second aspect of the present invention, the heat exchanger on the upstream side in the flow of the refrigerant in the gas cooler in each of the above inventions is disposed on the downstream side of the air flow ventilated in the gas cooler. The heat exchanger on the downstream side in the refrigerant flow in the gas cooler is arranged on the upstream side of the air flow ventilated in the gas cooler.
[0014]
According to the invention of claim 2 , in addition to each of the above inventions, a heat exchanger on the upstream side in the flow of refrigerant in the gas cooler is disposed on the downstream side of the air flow ventilated in the gas cooler, and the refrigerant in the gas cooler The heat exchanger on the downstream side in the flow of the gas is disposed upstream of the air flow ventilated in the gas cooler, so that the refrigerant flow in the gas cooler and the air flow vented in the gas cooler are referred to as a so-called counterflow. Will be able to.
[0015]
As a result, the air that is ventilated in the gas cooler passes through the heat exchanger having a lower temperature and then is ventilated to the heat exchanger having a higher temperature while the temperature is rising. The effect is improved, and the heat dissipation efficiency in the gas cooler can be further improved.
[0016]
The invention of claim 3 is characterized in that the refrigerant circuit using the CO ₂ refrigerant is used for air conditioning the passenger compartment.
[0017]
According to the invention of claim 3, since the vehicle interior can be air-conditioned by the refrigerant circuit using the CO ₂ refrigerant, in a so-called car air conditioner in which the leakage of the depression coolant is concerned, the safety for the environment and the user is improved. It will be able to improve significantly.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of an internal intermediate pressure type multi-stage (two-stage) compression rotary compressor 10 having first and second rotary compression elements 32 and 34 as an embodiment of a compressor constituting a refrigerant circuit of the present invention. 2 is a front view of the multistage compression rotary compressor 10, FIG. 3 is a side view of the multistage compression rotary compressor 10, and FIG. 4 shows a refrigerant circuit of the present invention.
[0019]
In each figure, 10 is an internal intermediate pressure type multi-stage compression rotary compressor using CO ₂ (carbon dioxide) as a refrigerant. This multi-stage compression rotary compressor 10 includes a cylindrical sealed container 12 made of a steel plate, The electric element 14 arranged and housed on the upper side of the internal space, and the first rotary compression element 32 (first stage) and the second arranged at the lower side of the electric element 14 and driven by the rotating shaft 16 of the electric element 14. This is composed of a rotary compression mechanism portion 18 composed of a rotary compression element 34 (second stage). The sealed container 12 has an oil reservoir at the bottom, a container main body 12A that houses the rotary compression mechanism 18 of the electric element 14, and a substantially bowl-shaped end cap (lid body) 12B that closes the upper opening of the container main body 12A. A circular mounting hole 12D is formed in the center of the upper surface of the end cap 12B, and a terminal (wiring is omitted) 20 for supplying power to the electric element 14 is mounted in the mounting hole 12D. It has been.
[0020]
The electric element 14 includes a stator 22 attached in an annular shape along the inner peripheral surface of the upper space of the hermetic container 12, and a rotor 24 inserted and installed inside the stator 22 with a slight gap. The rotor 24 is fixed to a rotating shaft 16 that passes through the center and extends in the vertical direction.
[0021]
The stator 22 has a laminated body 26 in which donut-shaped electromagnetic steel plates are laminated, and a stator coil 28 wound around the teeth of the laminated body 26 by a direct winding (concentrated winding) method. Similarly to the stator 22, the rotor 24 is also formed by a laminated body 30 of electromagnetic steel plates, and is formed by inserting a permanent magnet MG into the laminated body 30.
[0022]
An intermediate partition plate 36 is sandwiched between the first rotary compression element 32 and the second rotary compression element 34. That is, the first rotary compression element 32 and the second rotary compression element 34 include an intermediate partition plate 36, an upper cylinder 38 and a lower cylinder 40 disposed above and below the intermediate partition plate 36, and the upper and lower cylinders 38, The upper and lower rollers 46 and 48 that are eccentrically rotated by the upper and lower eccentric portions 42 and 44 provided on the rotary shaft 16 with a phase difference of 180 degrees in the interior 40, and the upper and lower cylinders 38 and 48 abut against the upper and lower rollers 46 and 48, The vanes 50 and 52 that divide the inside of the inside 40 into a low-pressure chamber side and a high-pressure chamber side, and the upper opening surface of the upper cylinder 38 and the lower opening surface of the lower cylinder 40 are closed to serve as bearings for the rotary shaft 16. The upper support member 54 and the lower support member 56 are used as support members.
[0023]
On the other hand, the upper support member 54 and the lower support member 56 are respectively provided with a suction passage 60 (the upper suction passage is not shown) that communicates with the inside of the upper and lower cylinders 38 and 40 through a suction port (not shown), and a part thereof is recessed. Discharge silencing chambers 62 and 64 formed by closing the recessed portion with an upper cover 66 and a lower cover 68 are provided.
[0024]
The discharge silencing chamber 64 and the inside of the sealed container 12 are communicated with each other through a communication passage that penetrates the upper and lower cylinders 38 and 40 and the intermediate partition plate 36, and an intermediate projecting pipe 121 is erected at the upper end of the communication passage. The intermediate pressure refrigerant compressed by the first rotary compression element 32 is discharged from the intermediate discharge pipe 121 into the sealed container 12.
[0025]
An upper cover 66 that closes the upper opening of the discharge silencing chamber 62 that communicates with the inside of the upper cylinder 38 of the second rotary compression element 34 partitions the inside of the sealed container 12 into the discharge silencing chamber 62 and the electric element 14 side. .
[0026]
In this case, the refrigerant is environmentally friendly and uses the carbon dioxide (CO ₂ ), which is a natural refrigerant in consideration of flammability and toxicity, and the oil as the lubricating oil is, for example, mineral oil (mineral oil) Existing oils such as alkylbenzene oil, ether oil, ester oil, and PAG (polyalkyl glycol) are used.
[0027]
On the side surface of the container main body 12A of the sealed container 12, the suction passage 60 (upper side is not shown) of the upper support member 54 and the lower support member 56, the discharge silencer chamber 62, the upper side of the upper cover 66 (on the lower end of the electric element 14). Sleeves 141, 142, 143, and 144 are welded and fixed at positions corresponding to (substantially corresponding positions). The sleeves 141 and 142 are adjacent to each other vertically, and the sleeve 143 is substantially diagonal to the sleeve 141. Further, the sleeve 144 is located at a position shifted by approximately 90 degrees from the sleeve 141.
[0028]
One end of a refrigerant introduction pipe 92 for introducing refrigerant gas into the upper cylinder 38 is inserted and connected into the sleeve 141, and one end of the refrigerant introduction pipe 92 communicates with a suction passage (not shown) of the upper cylinder 38. The refrigerant introduction pipe 92 passes through the upper side of the sealed container 12 to reach the sleeve 144, and the other end is inserted and connected into the sleeve 144 to communicate with the sealed container 12.
[0029]
In addition, one end of a refrigerant introduction pipe 94 for introducing refrigerant gas into the lower cylinder 40 is inserted and connected in the sleeve 142, and one end of the refrigerant introduction pipe 94 communicates with the suction passage 60 of the lower cylinder 40. The other end of the refrigerant introduction tube 94 is connected to the lower end of the accumulator 146. In addition, a refrigerant discharge pipe 96 is inserted and connected into the sleeve 143, and one end of the refrigerant introduction pipe 96 communicates with the discharge silencer chamber 62.
[0030]
The accumulator 146 is a tank that performs gas-liquid separation of the suction refrigerant, and is attached to a bracket 147 on the hermetic container side welded to the upper side surface of the container body 12A of the hermetic container 12 via a bracket 148 on the accumulator side. (FIG. 2).
[0031]
FIG. 4 shows a refrigerant circuit of a car air conditioner 153 as an embodiment to which the present invention is applied. In this figure, 154 is a gas cooler, 156 is an expansion valve as a pressure reducing device, 157 is an evaporator, the multi-stage compression rotary compressor 10 is disposed in an engine room of an automobile (not shown), and the refrigerant discharge pipe 96 is connected to the gas cooler. 154 is connected to the inlet.
[0032]
Each of the gas coolers 154 includes a plurality (three in the embodiment) of a refrigerant pipe 151 and a plurality of heat radiation fins (made of a thin aluminum plate) 152 attached to the refrigerant pipe 151 in a heat exchange manner. The heat exchangers 159A, 159B, and 159C are configured, and the heat exchangers 159A, 159B, and 159C are connected in series to the refrigerant flow. That is, the heat exchanger 159A is provided on the most upstream side of the refrigerant flow, and the refrigerant discharge pipe 96 is connected to the inlet of the refrigerant pipe 151 of the heat exchanger 159A. The inlet of the refrigerant pipe 151 of the heat exchanger 159B is connected to the outlet of the refrigerant pipe 151 of the heat exchanger 159A, and the inlet of the refrigerant pipe 151 of the heat exchanger 159C is connected to the outlet of the refrigerant pipe 151 of the heat exchanger 159B. And the outlet of the refrigerant pipe 151 of the heat exchanger 159C is connected to the expansion valve 156.
[0033]
Here, the inlet of the refrigerant pipe 151 of the heat exchanger 159A is on one side of the heat exchanger 159A, and the outlet is on the other side. The inlet of the refrigerant pipe 151 of the heat exchanger 159B is on the other side of the heat exchanger 159B, and the outlet is on one side. The inlet of the refrigerant pipe 151 of the heat exchanger 159C is on one side of the heat exchanger 159C, and the outlet is on the other side. Thereby, each heat exchanger 159A-159C is arranged in parallel with the inside of the grill of the engine room of the above-mentioned car, etc. so that mutual refrigerant piping 151 can be connected in the shortest distance.
[0034]
Further, the heat dissipating fins 152 of the heat exchanger 159A and the heat dissipating fins 152 of the heat exchanger 159B, and the heat dissipating fins 152 of the heat exchanger 159B and the heat dissipating fins 152 of the heat exchanger 159C are adjacent to each other. And are separated. Particularly in this case, the distance between the heat radiation fins 152, 152 on one side of the heat exchanger 159A that is the most upstream side of the refrigerant and one side of the heat exchanger 159B that is adjacent to the heat exchanger 159B (the gap A in FIG. 4). ) And the distance between the heat dissipating fins 152, 152 on one side of the heat exchanger 159B and one side of the most downstream heat exchanger 159C adjacent to the heat exchanger 159B (gap B in FIG. 4) is , Gap A> gap B. That is, the spacing between the heat radiation fins 15 2 and 15 2 of the heat exchangers 159A and 159B adjacent to each other on the upstream side of the refrigerant flow is equal to the heat radiation fin 15 of the heat exchangers 159B and 159C adjacent to each other on the downstream side of the refrigerant flow. 2, is arranged to be larger than 15 second intervals.
[0035]
Furthermore, the air that is ventilated to the gas cooler 154 first enters the heat exchanger 159C that is the most downstream of the refrigerant, passes through it, and then enters the heat exchanger 159B on the upstream side of the refrigerant and passes there. Thereafter, the heat exchangers 159A to 159C are arranged so as to finally flow into the heat exchanger 159A that is the uppermost stream of the refrigerant. That is, the heat exchanger 159A on the upstream side in the flow of the refrigerant in the gas cooler 154 is disposed on the downstream side of the air flow passed through the gas cooler 154, and the heat exchange on the downstream side in the flow of refrigerant in the gas cooler 154. Units 159B and 159C are arranged on the upstream side of the air flow ventilated by the gas cooler 154.
[0036]
The outlet of such a gas cooler 154 (the outlet of the refrigerant pipe 151 of the heat exchanger 159C) is connected to the expansion valve 156 by piping. The piping exiting the expansion valve 156 reaches the inlet of the evaporator 157, and the outlet of the evaporator 157 is connected to the refrigerant introduction pipe 94 via the accumulator 146. The evaporator 157 is attached to a ventilation path for air-conditioning the interior of the automobile. Reference numeral 158 denotes an intermediate heat exchanger for exchanging heat between the refrigerant exiting the gas cooler 154 and the refrigerant exiting the evaporator 157.
[0037]
Next, the operation will be described with the following configuration. When the stator coil 28 constituting the electric element 14 of the multistage compression rotary compressor 10 is energized from a battery (not shown) of the automobile via the terminal 20 and a wiring (not shown), the electric element 14 is activated and the rotor 24 rotates. By this rotation, the upper and lower rollers 46 and 48 are eccentrically rotated in the upper and lower cylinders 38 and 40 by being fitted to the upper and lower eccentric portions 42 and 44 provided integrally with the rotary shaft 16.
[0038]
Thus, the low-pressure refrigerant sucked into the low-pressure chamber side of the cylinder 40 from the suction port (not shown) via the suction passage 60 formed in the refrigerant introduction pipe 94 and the lower support member 56 is operated by the rollers 48 and the vanes 52. The intermediate pressure is compressed by the high pressure chamber side of the lower cylinder 40 from the discharge port (not shown), the discharge silencer chamber 64 formed in the lower support member 56, and the discharge from the intermediate discharge pipe 121 through the communication passage (not shown) into the sealed container 12. Is done. Thereby, the inside of the sealed container 12 becomes an intermediate pressure.
[0039]
The intermediate-pressure refrigerant gas in the sealed container 12 exits from the sleeve 144 and passes through a suction passage (not shown) formed in the refrigerant introduction pipe 92 and the upper support member 54, and then the low pressure of the upper cylinder 38 from the suction port (not shown). Inhaled into the room. The suctioned intermediate-pressure refrigerant gas is compressed in the second stage by the operation of the roller 46 and the vane 50 to become a high-temperature and high-pressure refrigerant gas, and is formed on the upper support member 54 from the high-pressure chamber side through a discharge port (not shown). The gas flows into the gas cooler 154 via the discharge silencer chamber 62 and the refrigerant discharge pipe 96.
[0040]
The temperature of the refrigerant flowing into the heat exchanger 159A of the gas cooler 154 reaches approximately + 100 ° C., but the CO ₂ refrigerant used at the critical point flows from the heat exchanger 159A to the heat exchangers 159B and 159C sequentially. Then, the air is cooled by the air ventilated there, and the temperature falls in the entire range of the gas cooler 154. Thereby, when leaving the heat exchanger 159B, the temperature falls to about + 50 ° C., and when leaving the heat exchanger 159C, it falls to + 30 ° C. to + 35 ° C.
[0041]
The refrigerant exiting the heat exchanger 159C (gas cooler 154) is decompressed by the expansion valve 156, then flows into the evaporator 157, evaporates, and absorbs heat from the surroundings. Due to this endothermic effect, the passenger compartment is cooled and air-conditioned. The refrigerant exiting the evaporator 157 repeats the cycle of being sucked into the first rotary compression element 32 from the refrigerant introduction pipe 94 via the accumulator 146.
[0042]
Here, radiation fins 15 2 of each heat exchanger 159A~159C constituting the gas cooler 154, because it is provided apart from each other as described above, positioned on the upstream side in the flow of the refrigerant in the gas cooler 154 the radiating fins 15 second heat of the heat exchanger 159A is, the heat radiation fins 15 and second heat exchanger 159B located downstream, and, to prevent a disadvantage that directly transmitted to the radiation fin 15 second heat exchanger 159C Can do. Moreover, the heat conduction by radiant heat is also suppressed.
[0043]
As a result, the heat exchanger 159B located on the downstream side, and further, the CO ₂ refrigerant whose temperature flowing in the heat exchanger 159C has decreased, are converted into the heat exchanger 159A located on the upstream side, and further the heat exchanger 159B. The problem of temperature rise due to heat is eliminated or suppressed, and the heat dissipation efficiency in the gas cooler 154 when a CO ₂ refrigerant is used can be significantly improved.
[0044]
Further, the heat radiation fins 15 2 and 15 2 of the heat exchangers 159A and 159B adjacent to each other on the upstream side of the refrigerant flow are spaced from the heat dissipation fins 15 2 and 152 of the heat exchangers 159B and 159C adjacent to each other on the downstream side of the refrigerant flow. since larger than the spacing of the fins 15 2, 15 2, while minimizing the gas cooler 154 the size enlargement of the whole caused by providing a gap between the heat radiating fins 15 2 of each heat exchanger 159A～159C, upstream It is possible to effectively prevent or suppress heat conduction from the heat exchanger 159A on the side to the heat exchanger 159B on the downstream side, and further to 159C.
[0045]
Further, as described above, the heat exchangers 159A and 159B on the upstream side in the flow of the refrigerant in the gas cooler 154 are arranged on the downstream side of the air flow ventilated in the gas cooler 154, and the downstream in the flow of the refrigerant in the gas cooler 154. Since the heat exchanger 159C on the side is arranged upstream of the flow of air that is ventilated to the gas cooler 154, the refrigerant flow in the gas cooler 154 and the flow of air that is ventilated in the gas cooler 154 are so-called opposites. It becomes a flow.
[0046]
As a result, the low-temperature air that is ventilated in the gas cooler 154 passes through the heat exchanger 159C having the lowest temperature and is then ventilated to the heat exchangers 159B and 159A having higher temperatures while the temperature is rising. As shown in FIG. 5, in the entire region of the gas cooler 154, the difference between the temperature of the CO ₂ refrigerant and the temperature of the air ventilated therein can be made substantially constant. Thereby, the cooling effect by the ventilation in the whole gas cooler 154 is improved, and the heat dissipation efficiency in the gas cooler 154 can be further improved.
[0047]
In particular, if the interior of an automobile is air-conditioned as in the embodiment, the so-called car air conditioner in which the leakage of the depression coolant is a concern, the safety and safety for the user can be remarkably improved. is there.
[0048]
In the embodiment, the gas cooler is configured with three heat exchangers, but is not limited thereto, and may be configured with two or four or more heat exchangers.
[0049]
【The invention's effect】
As described above in detail, according to the present invention, in the refrigerant circuit that includes the compressor and the gas cooler and dissipates the CO ₂ refrigerant discharged from the compressor by the gas cooler, the gas cooler exchanges heat with the refrigerant pipe and the refrigerant pipe, respectively. Each heat exchanger is connected in series with the flow of the refrigerant, and the heat dissipating fins of the adjacent heat exchangers are separated from each other. Therefore, it is possible to prevent or suppress the inconvenience that the heat of the radiating fin of the heat exchanger located upstream in the flow of the refrigerant in the gas cooler is transmitted to the radiating fin of the heat exchanger located downstream. It becomes possible to do.
[0050]
Accordingly, CO ₂ refrigerant temperature flowing through the heat exchanger located on the downstream side is reduced, eliminate a disadvantage that the temperature rise by the heat of the heat exchanger located on the upstream side, or suppressing, the CO ₂ refrigerant The heat radiation efficiency in the gas cooler of the refrigerant circuit used can be remarkably improved.
[0051]
Further , according to the present invention, in addition to the above, the interval between the heat dissipating fins of the heat exchangers adjacent to each other on the upstream side of the refrigerant flow is set so that the heat dissipating fins of the heat exchangers adjacent to each other on the downstream side of the refrigerant flow. Since it is larger than the interval, the heat from the upstream heat exchanger to the downstream heat exchanger is minimized while minimizing the overall size expansion of the gas cooler caused by providing an interval between the radiating fins of each heat exchanger. Conduction can be effectively prevented or suppressed.
[0052]
According to the invention of claim 2 , in addition to each of the above inventions, a heat exchanger on the upstream side in the flow of refrigerant in the gas cooler is disposed on the downstream side of the air flow ventilated in the gas cooler, and the refrigerant in the gas cooler The heat exchanger on the downstream side in the flow of the gas is disposed upstream of the air flow ventilated in the gas cooler, so that the refrigerant flow in the gas cooler and the air flow vented in the gas cooler are referred to as a so-called counterflow. Will be able to.
[0053]
As a result, the air that is ventilated in the gas cooler passes through the heat exchanger having a lower temperature and then is ventilated to the heat exchanger having a higher temperature while the temperature is rising. The effect is improved, and the heat dissipation efficiency in the gas cooler can be further improved.
[0054]
According to the invention of claim 3, since the vehicle interior can be air-conditioned by the refrigerant circuit using the CO ₂ refrigerant, in a so-called car air conditioner in which the leakage of the depression coolant is concerned, the safety for the environment and the user is improved. It will be able to improve significantly.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a multi-stage compression rotary compressor as an embodiment of a compressor used in the present invention.
2 is a front view of the rotary compressor of FIG. 1. FIG.
3 is a side view of the rotary compressor of FIG. 1. FIG.
FIG. 4 is a refrigerant circuit diagram of a car air conditioner to which the present invention is applied.
5 is a graph showing the relationship between the temperature of the CO ₂ refrigerant in the gas cooler in FIG. 4 and the temperature of the air ventilated through it.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Multistage compression type rotary compressor 12 Airtight container 14 Electric element 16 Rotating shaft 18 Rotation compression mechanism part 32 1st rotation compression element 34 2nd rotation compression element 151 Refrigerant piping 152 Radiation fin 154 Gas cooler 159A-159C Heat exchanger

Claims (3)

In a refrigerant circuit comprising a compressor and a gas cooler, and dissipating the CO ₂ refrigerant discharged from the compressor with the gas cooler,
The gas cooler is composed of a plurality of heat exchangers each composed of a refrigerant pipe and a heat radiation fin attached to the refrigerant pipe in a heat exchange manner,
While connecting each heat exchanger in series with the refrigerant flow,
The heat dissipating fins of the adjacent heat exchangers are arranged so as to be separated from each other and the distance between the heat dissipating fins of the adjacent heat exchangers on the upstream side of the refrigerant flow is set to be adjacent to each other on the downstream side of the refrigerant flow. A refrigerant circuit using a CO ₂ refrigerant characterized in that it is larger than the interval between the radiation fins of each heat exchanger . The heat exchanger on the upstream side in the flow of refrigerant in the gas cooler is disposed on the downstream side of the flow of air ventilated in the gas cooler, and the heat exchanger on the downstream side in the flow of refrigerant in the gas cooler Is disposed upstream of the flow of air ventilated through the gas cooler. ₂ Refrigerant circuit using refrigerant. The CO according to claim 1 or 2, wherein the CO is used to air-condition a vehicle interior. ₂ Refrigerant circuit using refrigerant.

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