Accumulator unit, heat exchange module, and refrigeration cycle

Abstract

This technology provides space-saving solutions for refrigeration cycles employing a two-stage compression cycle. [Solution] The refrigeration cycle includes a refrigerant circulation passage that allows refrigerant discharged from the compressor 102 to circulate, passing sequentially through a first heat exchanger 104, a first expansion valve 124, a second heat exchanger 106, and an accumulator 120, and returning to the compressor 102 via an intake port 102a; a bypass passage 130 that branches off at a branching point P1 in the refrigerant circulation passage and connects to an intermediate port 102c of the compressor 102; a second expansion valve 126 provided in the bypass passage 130; and an internal heat exchanger 122 that performs heat exchange between the refrigerant sent to the first expansion valve 124 via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve 126 in the bypass passage. The accumulator 120 and the internal heat exchanger 122 are provided as a single unit. The refrigerant in the accumulator 120 exchanges heat with the refrigerant sent to the first expansion valve 124 via the branching point.

Description

Technical Field

[0001] The present invention relates to the structure of an accumulator applied to a refrigeration cycle.

Background Art

[0002] With the recent spread of electric vehicles, the development of their air conditioning systems has also been promoted. Electric vehicles do not have a heat source by an internal combustion engine itself. Therefore, a heat pump system that performs cycle operation using a refrigerant for both cooling and heating is often adopted. In the heat pump system, the heat absorbed from the outside air and the heat generated by the power of the compressor are added and dissipated in the heating operation in winter, so that the energy (electric power) used can be suppressed. Therefore, it is also possible to suppress the reduction in the vehicle's cruising range compared to a system using an electric heater or the like.

[0003] However, as the outside air temperature decreases, the amount of heat absorbed decreases, making it difficult to maintain the performance of the heat pump system. Therefore, a heat pump system that improves heating performance by adopting a so-called two-stage compression cycle has also been proposed (see Patent Document 1). In this system, the compressor has an intermediate port between the suction port and the discharge port, and compresses the refrigerant introduced from each of the suction port and the intermediate port and discharges it from the discharge port.

[0004] Such a system has a refrigeration cycle including a compressor, a first heat exchanger (condenser), a first expansion valve, and a second heat exchanger (evaporator). This refrigeration cycle has a refrigerant circulation passage through which the refrigerant discharged from the discharge port of the compressor returns to the suction port of the compressor via the first heat exchanger, the first expansion valve, and the second heat exchanger. Further, a bypass passage that branches on the downstream side of the first heat exchanger in the refrigerant circulation passage and connects to the intermediate port of the compressor is provided. A second expansion valve is provided in the bypass passage. And an internal heat exchanger is provided so that both the refrigerant circulation passage and the bypass passage pass through on the downstream side of the second expansion valve.

[0005] In this configuration, the refrigerant that has passed through the first heat exchanger flows directly through the refrigerant circulation passage to the internal heat exchanger on one hand, and through the bypass passage on the other hand, is depressurized by the second expansion valve and then introduced to the internal heat exchanger. At this time, heat exchange occurs in the internal heat exchanger between the refrigerant flowing through the refrigerant circulation passage and the refrigerant flowing through the bypass passage. The refrigerant that has passed through the second expansion valve is heated in the internal heat exchanger, becoming a highly dry gaseous refrigerant, which is then introduced into the intermediate port of the compressor.

[0006] In other words, the refrigerant circulating through the refrigerant circulation passage and being led to the compressor's intake port, and the refrigerant being led through the bypass passage to the compressor's intermediate port, are both compressed. As a result, the flow rate of refrigerant discharged from the compressor increases, improving the condensation performance of the refrigerant in the first heat exchanger. Furthermore, the refrigerant that has passed through the internal heat exchanger in the refrigerant circulation passage is led to the first expansion valve as a liquid refrigerant with reduced supercooling and low enthalpy, thus improving the heat absorption performance of the second heat exchanger. As a result, the heating performance of the refrigeration cycle can be improved. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2017 / 061233 [Overview of the project] [Problems that the invention aims to solve]

[0008] In such refrigeration cycles, an accumulator (gas-liquid separator) is often installed upstream of the compressor. The accumulator separates the refrigerant into gas and liquid phases, supplying only the gaseous refrigerant to the compressor, thereby preventing compressor failure due to liquid compression. However, when constructing a heat pump system as described above, the number of components increases due to the inclusion of an internal heat exchanger and a second expansion valve in addition to the accumulator, and space problems are likely to arise due to the need for piping to connect these devices.

[0009] One of the objectives of the present invention is to provide a technology that can achieve space savings in a refrigeration cycle employing a two-stage compression cycle. [Means for solving the problem]

[0010] One aspect of the present invention is an accumulator unit applied to a refrigeration cycle for a vehicle air conditioning system. This refrigeration cycle includes a compressor having an intermediate port between an intake port and a discharge port, which compresses refrigerant introduced from the intake port and the intermediate port, respectively, and discharges it from the discharge port; a first heat exchanger that dissipates heat from the refrigerant discharged from the compressor; a first expansion valve that expands the refrigerant that has passed through the first heat exchanger; a second heat exchanger that evaporates the refrigerant expanded by the first expansion valve; an accumulator that separates the refrigerant that has passed through the second heat exchanger into gas and liquid phases, stores it, and leads the gas phase refrigerant toward the intake port of the compressor; and a discharge valve that is discharged from the compressor. The system includes a refrigerant circulation passage that allows the discharged refrigerant to circulate, passing sequentially through a first heat exchanger, a first expansion valve, a second heat exchanger, and an accumulator, and returning to the compressor via an intake port; a bypass passage that branches off at a branching point between the first heat exchanger and the first expansion valve in the refrigerant circulation passage and connects to an intermediate port of the compressor; a second expansion valve provided in the bypass passage; and an internal heat exchanger that performs heat exchange between the refrigerant sent to the first expansion valve via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve in the bypass passage. The accumulator unit is an integrated unit comprising the accumulator and the internal heat exchanger. The refrigerant in the accumulator exchanges heat with the refrigerant sent to the first expansion valve via the branching point.

[0011] According to this embodiment, an accumulator unit is provided in which the accumulator and the internal heat exchanger are integrated into one unit. As a result, piping and other connections between the accumulator and the internal heat exchanger are eliminated or at least reduced. By applying this accumulator unit, space savings can be achieved in refrigeration cycles employing a two-stage compression cycle.

[0012] Another aspect of the present invention is a heat exchange module applied to a vehicle air conditioning system. This vehicle air conditioning system comprises a first water circulation path provided with a cooler core for cooling, a second water circulation path provided with a heater core for heating, and a refrigeration cycle that exchanges heat between the first water circulation path and the second water circulation path, respectively. The refrigeration cycle includes a compressor having an intermediate port between an intake port and a discharge port, which compresses the refrigerant introduced from the intake port and the intermediate port, respectively, and discharges it from the discharge port; a first heat exchanger that dissipates heat from the refrigerant discharged from the compressor and exchanges heat with the second water circulation path; a first expansion valve that expands the refrigerant that has passed through the first heat exchanger; a second heat exchanger that evaporates the refrigerant expanded by the first expansion valve and exchanges heat with the first water circulation path; and a valve that separates the refrigerant that has passed through the second heat exchanger into gas and liquid phases, stores it, and leads the gas phase portion of the refrigerant toward the intake port of the compressor. The heat exchange module comprises a cumulator, a refrigerant circulation passage that allows refrigerant discharged from the compressor to circulate so that it passes sequentially through a first heat exchanger, a first expansion valve, a second heat exchanger, and the accumulator and returns to the compressor through an intake port, a bypass passage that branches off at a branching point between the first heat exchanger and the first expansion valve in the refrigerant circulation passage and connects to an intermediate port of the compressor, a second expansion valve provided in the bypass passage, and an internal heat exchanger that performs heat exchange between the refrigerant sent to the first expansion valve via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve in the bypass passage. The heat exchange module integrates the accumulator, internal heat exchanger, first expansion valve, and second expansion valve into a single unit.

[0013] According to this embodiment, a heat exchange module is provided in which an accumulator, an internal heat exchanger, a first expansion valve, and a second expansion valve are integrated into one unit. As a result, piping and other connections between these components are eliminated or at least reduced. By applying this heat exchange module, space savings can be achieved in refrigeration cycles employing a two-stage compression cycle.

[0014] A further aspect of the present invention is a refrigeration cycle for a vehicle air conditioning system. This refrigeration cycle comprises a compressor having an intermediate port between an intake port and a discharge port, which compresses the refrigerant introduced from the intake port and the intermediate port, respectively, and discharges it from the discharge port; a first heat exchanger that dissipates heat from the refrigerant discharged from the compressor; a first expansion valve that expands the refrigerant that has passed through the first heat exchanger; a second heat exchanger that evaporates the refrigerant expanded by the first expansion valve; an accumulator that separates the refrigerant that has passed through the second heat exchanger into gas and liquid phases and stores it, and leads the gas phase refrigerant toward the intake port of the compressor; and a discharge port from the compressor. The system includes a refrigerant circulation passage that allows the discharged refrigerant to circulate, passing sequentially through a first heat exchanger, a first expansion valve, a second heat exchanger, and an accumulator, and returning to the compressor via an intake port; a bypass passage that branches off at a branching point between the first heat exchanger and the first expansion valve in the refrigerant circulation passage and connects to an intermediate port of the compressor; a second expansion valve provided in the bypass passage; and an internal heat exchanger that performs heat exchange between the refrigerant sent to the first expansion valve via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve in the bypass passage. The accumulator and the internal heat exchanger are provided as an integrated accumulator unit. The refrigerant in the accumulator exchanges heat with the refrigerant sent to the first expansion valve via the branching point.

[0015] According to this embodiment, an accumulator unit in which the accumulator and the internal heat exchanger are integrated is applied to a refrigeration cycle employing a two-stage compression cycle. As a result, piping and other connections between these components are eliminated or at least reduced, enabling space savings in the refrigeration cycle. [Effects of the Invention]

[0016] According to the present invention, a technology is available that enables space saving in a refrigeration cycle employing a two-stage compression cycle. [Brief explanation of the drawing]

[0017] [Figure 1] This is a system configuration diagram of a vehicle air conditioning and heating system according to the first embodiment. [Figure 2]It is a cross-sectional view showing the configuration of the accumulator unit. [Figure 3] It is a diagram showing the operation of the air conditioner. [Figure 4] It is a diagram showing the operation of the air conditioner. [Figure 5] It is a diagram showing the operation of the air conditioner. [Figure 6] It is a system configuration diagram of the vehicle air conditioner according to the second embodiment. [Figure 7] It is a diagram showing the operation of the air conditioner. [Figure 8] It is a diagram showing the operation of the air conditioner. [Figure 9] It is a diagram showing the configuration of the heat exchange module. [Figure 10] It is a diagram showing the configuration of the heat exchange module.

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for convenience, the positional relationship of each structure may be expressed based on the illustrated state. Also, for the following embodiments and their modifications, substantially the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0019] [First Embodiment] FIG. 1 is a system configuration diagram of the vehicle air conditioner according to the first embodiment. The air conditioner 100 includes a refrigeration cycle (refrigerant circulation circuit) in which a compressor 102, an auxiliary condenser 104, an outdoor heat exchanger 106, an accumulator unit 108, an evaporator 110, etc. are connected by piping. The auxiliary condenser 104 functions as a “first heat exchanger”, and the outdoor heat exchanger 106 functions as a “second heat exchanger”. The air conditioner 100 is configured as a heat pump system that performs air conditioning in the vehicle interior by using the heat of the refrigerant while the refrigerant such as HFO-1234yf circulates in the refrigeration cycle while changing its state.

[0020] The compressor 102, outdoor heat exchanger 106, and accumulator unit 108 are located outside the vehicle (in the engine compartment). Meanwhile, an indoor air conditioning unit 112 is provided inside the vehicle where heat exchange of air takes place. In the ducts constituting the indoor air conditioning unit 112, a blower 113, an evaporator 110, and an auxiliary condenser 104 are arranged from the upstream side in the direction of airflow. An air mix door 114 is rotatably provided upstream of the auxiliary condenser 104, and the ratio of the airflow passing through the auxiliary condenser 104 to the airflow bypassing the auxiliary condenser 104 is adjusted.

[0021] The accumulator unit 108 integrates an accumulator 120, an internal heat exchanger 122, a first expansion valve 124, and a second expansion valve 126 (details will be described later).

[0022] The air conditioning and heating system 100 is operated in such a way that it switches between multiple refrigerant circulation passages during cooling operation and heating operation. This refrigeration cycle is configured such that the auxiliary condenser 104 and the outdoor heat exchanger 106 can operate in series as condensers, and the evaporator 110 and the outdoor heat exchanger 106 can be switched as evaporators. A first refrigerant circulation passage is formed through which the refrigerant circulates during cooling operation, and a second refrigerant circulation passage is formed through which the refrigerant circulates during heating operation.

[0023] In this embodiment, a two-stage compression cycle is employed, enabling not only normal heating operation but also a specific heating operation that further enhances the performance of the heating operation. During this specific heating operation, a third refrigerant circulation passage is formed in addition to the second refrigerant circulation passage. To achieve two-stage compression, the compressor 102 has an intermediate port 102c between the intake port 102a for drawing in refrigerant and the discharge port 102b for discharging refrigerant.

[0024] The first refrigerant circulation passage is a passage through which the refrigerant circulates as follows: compressor 102 → auxiliary condenser 104 → internal heat exchanger 122 → first expansion valve 124 → outdoor heat exchanger 106 → evaporator 110 → accumulator 120 → compressor 102 (see Figure 3). The second refrigerant circulation passage is a passage through which the refrigerant circulates as follows: compressor 102 → auxiliary condenser 104 → internal heat exchanger 122 → first expansion valve 124 → outdoor heat exchanger 106 → accumulator 120 → compressor 102 (see Figure 4). In other words, the second refrigerant circulation passage is a passage that bypasses the evaporator 110.

[0025] The third refrigerant circulation passage is a passage through which the refrigerant circulates as follows: compressor 102 → auxiliary condenser 104 → second expansion valve 126 → internal heat exchanger 122 → compressor 102 (see Figure 5). In other words, the third refrigerant circulation passage includes a bypass passage 130 that branches off from the second refrigerant circulation passage at branching point P1 and bypasses the equipment downstream of the internal heat exchanger 122. The second expansion valve 126 is located in the bypass passage 130.

[0026] The accumulator unit 108 has inlet ports 108a to 108c for introducing refrigerant and outlet ports 108d to 108f for releasing refrigerant. Inlet port 108a functions as the "first inlet port", inlet port 108b functions as the "second inlet port", and inlet port 108c functions as the "third inlet port". Outlet port 108d functions as the "first outlet port", outlet port 108e functions as the "second outlet port", and outlet port 108f functions as the "third outlet port".

[0027] The accumulator unit 108 has internal passages: a first passage 141 connecting the inlet port 108a and the outlet port 108d, a second passage 142 connecting the inlet port 108b and the outlet port 108e, and a third passage 143 connecting the inlet port 108c and the outlet port 108f. The first passage 141 and the third passage 143 constitute the first and second refrigerant circulation passages, and the second passage 142 constitutes the third refrigerant circulation passage. When the internal heat exchanger 122 is functioning, heat exchange occurs between the refrigerant flowing through the first passage 141 and the refrigerant flowing through the second passage 142. The first expansion valve 124 adjusts the opening degree of the first passage 141, and the second expansion valve 126 adjusts the opening degree of the second passage 142. The third passage 143 constitutes an internal passage of the accumulator 120.

[0028] The discharge port 102b of the compressor 102 is connected to the inlet of the auxiliary condenser 104 via the first passage 131. The outlet of the auxiliary condenser 104 is connected to the introduction ports 108a and 108b of the accumulator unit 108 via the second passage 132. That is, the second passage 132 branches at branching point P1, with one branch connecting to introduction port 108a and the other connecting to introduction port 108b.

[0029] The outlet port 108d of the accumulator unit 108 is connected to the inlet of the outdoor heat exchanger 106 via the third passage 133. The outlet of the outdoor heat exchanger 106 is connected to the inlet of the evaporator 110 via the fourth passage 134. The outlet of the evaporator 110 is connected to the introduction port 108c (inlet of the accumulator 120) of the accumulator unit 108 via the fifth passage 135. The outlet port 108f (outlet of the accumulator 120) is connected to the suction port 102a of the compressor 102 via the sixth passage 136. The outlet port 108e is connected to the intermediate port 102c of the compressor 102 via the seventh passage 137. In other words, the second flow path 142 and the seventh passage 137 constitute the bypass passage 130.

[0030] A third expansion valve 128 is provided upstream of the evaporator 110 in the fourth passage 134. A check valve 150 is provided downstream of the evaporator 110 in the fifth passage 135. A bypass passage 138 is provided connecting a branching point P2 provided upstream of the third expansion valve 128 in the fourth passage 134 and a connection point P3 provided downstream of the check valve 150 in the fifth passage 135. The bypass passage 138 is a passage for the refrigerant to bypass the evaporator 110. An on-off valve 152 is provided in the bypass passage 138. In this embodiment, the on-off valve 152 is a solenoid-driven electromagnetic valve, but it may also be a motor-driven electric valve.

[0031] PT sensors 154 and 156 for detecting the refrigerant pressure and temperature are provided near the outlet of the outdoor heat exchanger 106 in the fourth passage 134 and near the inlet of the compressor 102 in the sixth passage 136, respectively.

[0032] With this configuration, a first refrigerant circulation passage is formed by the first passage 131, the second passage 132, the first flow path 141, the third passage 133, the fourth passage 134, the fifth passage 135, the third flow path 143, and the sixth passage 136 (see Figure 3). Furthermore, a second refrigerant circulation passage is formed by the first passage 131, the second passage 132, the first flow path 141, the third passage 133, the fourth passage 134 (upstream of branching point P2), the bypass passage 138, the fifth passage 135 (downstream of connection point P3), the third flow path 143, and the sixth passage 136 (see Figure 4). In addition, a third refrigerant circulation passage is formed by the first passage 131, the second passage 132, the second flow path 142, and the seventh passage 137 (see Figure 5). Details of these will be described later.

[0033] The compressor 102 is configured as an electric compressor, housing a motor and a compression mechanism within a housing. The compressor 102 is driven by a current supplied from a battery (not shown), and the refrigerant discharge flow rate changes according to the motor's rotational speed. The compressor 102 achieves two-stage compression by compressing the refrigerant introduced from the intake port 102a and the intermediate port 102c, respectively, and discharging it from the discharge port 102b. Since such compressors are well known, their description is omitted.

[0034] The auxiliary condenser 104 functions as an indoor condenser that dissipates heat from the refrigerant separately from the outdoor heat exchanger 106. In other words, the high-temperature, high-pressure refrigerant discharged from the compressor 102 dissipates heat as it passes through the auxiliary condenser 104.

[0035] The outdoor heat exchanger 106 functions as an outdoor condenser that releases heat from the refrigerant passing through it during cooling operation, while it functions as an outdoor evaporator that evaporates the refrigerant passing through it during heating operation. The outdoor heat exchanger 106 facilitates heat exchange between the outside air and the refrigerant.

[0036] The on-off valve 152 switches the flow of refrigerant in the refrigerant circulation passage according to the operating state of the refrigeration cycle. During cooling operation, the on-off valve 152 is closed and the third expansion valve 128 is opened. This opens the first refrigerant circulation passage and blocks the second refrigerant circulation passage. During heating operation, the third expansion valve 128 is closed and the on-off valve 152 is opened. This blocks the first refrigerant circulation passage and opens the second refrigerant circulation passage.

[0037] In this embodiment, the third expansion valve 128 is an electrically operated valve that, during cooling operation, throttles and expands the liquid refrigerant discharged from the outdoor heat exchanger 106 and supplies it to the evaporator 110.

[0038] The evaporator 110 functions as an indoor evaporator that evaporates the refrigerant passing through it. The refrigerant, which has become low temperature and low pressure after passing through the third expansion valve 128, evaporates as it passes through the evaporator 110. Air introduced from the upstream side of the indoor air conditioning unit 112 is cooled by its latent heat of vaporization. At this time, the cooled and dehumidified air is divided into two parts: one that passes through the auxiliary condenser 104 and the other that bypasses the auxiliary condenser 104, depending on the opening degree of the air mix door 114. The air that passes through the auxiliary condenser 104 is heated during its passage. The air that has passed through the auxiliary condenser 104 and the bypassed air are mixed downstream of the auxiliary condenser 104 and adjusted to the target temperature, and supplied into the vehicle from an outlet (not shown).

[0039] The air conditioning system 100, configured as described above, is controlled by the control unit 160. The control unit 160 calculates the control amount for each actuator to achieve the room temperature set by the vehicle occupants and outputs a control signal to the drive circuit of each actuator. Based on predetermined external information detected by various sensors such as PT sensors 154 and 156, including the temperature inside and outside the vehicle and the temperature of the air blown out of the evaporator 110, the control unit 160 determines the control amount (open / closed state) of each control valve and the drive amount of the compressor 102, and supplies a control current to drive them. The compressor 102 compresses the refrigerant introduced from the intake port 102a and the intermediate port 102c and discharges high-temperature, high-pressure refrigerant from the discharge port 102b.

[0040] Figure 2 is a cross-sectional view showing the configuration of the accumulator unit 108. The accumulator unit 108 is constructed by integrally assembling an accumulator 120, an internal heat exchanger 122, a first expansion valve 124, and a second expansion valve 126. The accumulator unit 108 has a cylindrical housing 10 that houses the accumulator 120. The housing 10 constitutes part of the internal heat exchanger 122. The first expansion valve 124 is assembled to one end (lower end) of the housing 10, and the second expansion valve 126 is assembled to the other end (upper end) of the housing 10.

[0041] The accumulator 120 has a cylindrical tank 12, which is coaxially housed in the housing 10. A gas phase section GA and a liquid phase section LA are formed at the top and bottom of the tank 12. Inside the tank 12, a U-shaped refrigerant pipe 14 is arranged, having a refrigerant inlet and outlet at its top. One end 14a of the refrigerant pipe 14 opens into the gas phase section GA of the tank 12, and the other end 14b penetrates the upper end of the tank 12 and has an outlet port 108f. A small hole 14c is provided at the bottom of the refrigerant pipe 14. Lubricating oil contained in the refrigerant accumulates at the bottom of the tank 12 (liquid phase section LA). This lubricating oil is drawn out through the small hole 14c and supplied to the compressor 102 via the external pipe 22. The space of the gas phase section GA and the internal passage of the refrigerant pipe 14 form the third flow path 143 described above.

[0042] The top surface of the tank 12 constitutes the top surface of the housing 10, with an inlet port 108c provided in its center and an outlet port 108f provided near the periphery. External piping 20 forming the fifth passage 135 is connected to the inlet port 108c, and external piping 22 forming the sixth passage 136 is connected to the outlet port 108f (see Figure 1).

[0043] An umbrella-shaped rectifier plate 16 is positioned at the top of the tank 12. External piping 20 opens directly above the rectifier plate 16, and one end 14a of refrigerant piping 14 opens directly below the rectifier plate 16. The refrigerant introduced through the introduction port 108c is slowed down by hitting the upper surface of the rectifier plate 16. The rectifier plate 16 guides the liquid phase component of the refrigerant to the peripheral edge of the tank 12 before dripping it into the liquid phase section LA below. Since one end 14a of refrigerant piping 14 is located directly below the center of the lower surface of the rectifier plate 16, the liquid phase component is prevented from directly flowing into refrigerant piping 14. In other words, refrigerant piping 14 introduces gaseous refrigerant from one end 14a and leads it out towards the compressor 102 from the other end 14b.

[0044] Internal piping 30 is provided along the outer circumferential surface of the tank 12. The internal piping 30 is constructed by arranging a plurality of cylindrical pipes (cylindrical pipes 30a) in the longitudinal direction of the tank 12, and connecting adjacent cylindrical pipes 30a in the longitudinal direction of the tank 12 with connecting pipes (not shown). In other words, a plurality of cylindrical pipes 30a are interconnected to constitute the internal piping 30. One end (upper end) of the internal piping 30 is connected to the second expansion valve 126, and the other end (lower end) is connected to the first expansion valve 124. A first flow path 141 is formed inside the internal piping 30. On the other hand, a second flow path 142 is formed between the inner circumferential surface of the housing 10 and the outer circumferential surface of the internal piping 30, that is, in the space within the housing 10 that encloses the internal piping 30. In other words, the housing 10 and the internal piping 30 function as an internal heat exchanger 122 that performs heat exchange between the refrigerant flowing through the first flow path 141 and the refrigerant flowing through the second flow path 142. In the modified example, the internal piping 30 may be a spiral pipe wrapped around the outer surface of the tank 12.

[0045] The first expansion valve 124 is, for example, an electric valve (electronic expansion valve) as described in Japanese Patent Publication No. 2022-146574. The body 32 of the first expansion valve 124 constitutes the lower end of the housing 10. A first refrigerant passage 34 and a second refrigerant passage 36 are provided so as to penetrate the body 32. The first refrigerant passage 34 constitutes a first flow path 141 and is provided with the valve portion of the first expansion valve 124. The first refrigerant passage 34 has the lower end of the internal piping 30 connected to its upstream end and has an outlet port 108d at its downstream end. The second refrigerant passage 36 constitutes a second flow path 142 and has an outlet port 108e at its downstream end.

[0046] The second expansion valve 126 is also an electrically operated valve (electronic expansion valve), such as the one described in Japanese Patent Publication No. 2023-53708. The body 42 of the second expansion valve 126 constitutes the upper end of the housing 10. The body 42 is provided with a first refrigerant passage 44 and a second refrigerant passage 46. The first refrigerant passage 44 constitutes a second flow path 142, and the valve portion of the second expansion valve 126 is provided therein. The first refrigerant passage 44 has an introduction port 108b at its upstream end. The second refrigerant passage 46 constitutes a first flow path 141 and has an introduction port 108a at its upstream end. The second expansion valve 126 is opened only when two-stage compression is performed by the compressor 102.

[0047] In this configuration, the refrigerant introduced from the inlet port 108a is introduced into the internal piping 30 (first flow path 141) via the second refrigerant passage 46, flows around the accumulator 120, and is led to the first refrigerant passage 34. This refrigerant then passes through the valve section of the first expansion valve 124 and is led out from the outlet port 108d toward the outdoor heat exchanger 106.

[0048] Meanwhile, the refrigerant introduced from the inlet port 108b is introduced into the first refrigerant passage 44. After passing through the valve section of the second expansion valve 126, this refrigerant flows through the space between the housing 10 and the internal piping 30 (second flow path 142) and is led to the second refrigerant passage 36, and is led out from the outlet port 108e toward the intermediate port 102c of the compressor 102.

[0049] The refrigerant introduced into the accumulator 120 from the inlet port 108c is separated into gas and liquid phases inside the accumulator 120 and stored there, and its gaseous component (gas refrigerant) is introduced into one end 14a of the refrigerant piping 14. This refrigerant passes through the refrigerant piping 14 and is discharged from the outlet port 108f towards the suction port 102a of the compressor 102.

[0050] Next, the operation of the refrigeration cycle in this embodiment will be described. Figures 3 to 5 illustrate the operation of the heating and cooling system 100. Figure 3 shows the cooling operation state, Figure 4 shows the normal heating operation state, and Figure 5 shows the specific heating operation state. "Specific heating operation" is an operating state in which heating performance is enhanced under extremely low temperature conditions. The upper part of each figure shows a Mollier diagram explaining the operation of the refrigeration cycle. The horizontal axis represents enthalpy, and the vertical axis represents various pressures. The lower part of each figure shows the operating state of the refrigeration cycle. The thick lines and arrows in the figures indicate the flow of refrigerant, and the symbols a to h correspond to those in the Mollier diagram. Also, the "×" in the figures indicates that the flow of refrigerant is blocked.

[0051] (Air conditioning operation) As shown in Figure 3, during cooling operation, the first expansion valve 124 and the third expansion valve 128 are in the open state, and the second expansion valve 126 and the on / off valve 152 are in the closed state. As a result, the first refrigerant circulation passage is opened, and the second and third refrigerant circulation passages are blocked. The air mix door 114 is closed. At this time, the first expansion valve 124 is in the fully open state, so it does not perform its expansion function. On the other hand, the third expansion valve 128 is controlled to a small opening and performs its expansion function. The outdoor heat exchanger 106 functions as an outdoor condenser.

[0052] The high-temperature, high-pressure refrigerant discharged from the compressor 102 passes through the auxiliary condenser 104, but since the air mix door 114 is closed, no heat exchange occurs with the air inside the vehicle. This refrigerant dissipates heat by exchanging heat with the refrigerant in the accumulator 120 as it passes through the first flow path 141 of the accumulator unit 108. Subsequently, the refrigerant that has dissipated heat into the outside air is condensed in the outdoor heat exchanger 106, becoming liquid refrigerant.

[0053] The liquid refrigerant discharged from the outdoor heat exchanger 106 is throttled and expanded by the third expansion valve 128, becoming a low-temperature, low-pressure atomized refrigerant which is then introduced into the evaporator 110. As the refrigerant passes through the evaporator 110, it evaporates, cooling the air inside the vehicle. The refrigerant discharged from the evaporator 110 is separated into gas and liquid phases in the accumulator 120, and the gaseous phase component is guided to the intake port 102a of the compressor 102. As described above, the refrigerant in the accumulator 120 exchanges heat with the high-temperature refrigerant passing through the first flow path 141, thus reliably becoming a gaseous refrigerant. This gaseous refrigerant is then returned to the compressor 102.

[0054] (Normal heating operation) As shown in Figure 4, during normal heating operation, the first expansion valve 124 and the on-off valve 152 are in the open state, and the second expansion valve 126 and the third expansion valve 128 are in the closed state. As a result, the second refrigerant circulation passage is opened, and the first and third refrigerant circulation passages are blocked. The air mix door 114 is wide open. At this time, the first expansion valve 124 is controlled to a small opening and performs its expansion function. The refrigerant does not pass through the evaporator 110, and the evaporator 110 effectively ceases to function. The outdoor heat exchanger 106 functions as an evaporator (outdoor evaporator).

[0055] The refrigerant discharged from the compressor 102 is condensed by passing through the auxiliary condenser 104. At this time, the interior of the vehicle is warmed by heat exchange in the auxiliary condenser 104. The refrigerant that has passed through the auxiliary condenser 104 dissipates heat by exchanging heat with the refrigerant in the accumulator 120 as it passes through the first flow path 141 of the accumulator unit 108. After that, it is throttled and expanded in the first expansion valve 124, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant and introduced into the outdoor heat exchanger 106. As the refrigerant passes through the outdoor heat exchanger 106, it evaporates and absorbs heat from the outside. The refrigerant discharged from the outdoor heat exchanger 106 reliably becomes a gaseous refrigerant by exchanging heat with the high-temperature refrigerant passing through the first flow path 141 of the accumulator unit 108. The gaseous component (gas refrigerant) of the refrigerant separated into gas and liquid phases in the accumulator 120 is returned to the compressor 102.

[0056] (Specific heating operation) As shown in Figure 5, in specific heating operation, the first expansion valve 124, the second expansion valve 126, and the on / off valve 152 are in the open state, and the third expansion valve 128 is in the closed state. As a result, the second and third refrigerant circulation passages are opened, and the first refrigerant circulation passage is blocked. In other words, the bypass passage 130 is opened compared to the normal heating state. The air mix door 114 is opened wide.

[0057] The refrigerant discharged from the compressor 102 circulates through the second refrigerant circulation passage, as in normal heating operation, and also through the third refrigerant circulation passage. That is, the discharged refrigerant is condensed by passing through the auxiliary condenser 104. At this time, the interior of the vehicle is heated by heat exchange in the auxiliary condenser 104. The refrigerant that has passed through the auxiliary condenser 104 branches off at branching point P1. One of the branched refrigerants dissipates heat by exchanging heat with the refrigerant in the accumulator 120 as it passes through the first flow path 141 of the accumulator unit 108. This refrigerant is throttled and expanded in the first expansion valve 124, becoming a low-temperature, low-pressure mist-like refrigerant and introduced into the outdoor heat exchanger 106. As the refrigerant passes through the outdoor heat exchanger 106, it evaporates and absorbs heat from the outside. The refrigerant discharged from the outdoor heat exchanger 106 reliably becomes a gaseous refrigerant by exchanging heat with the high-temperature refrigerant passing through the first flow path 141 of the accumulator unit 108. The gaseous component (gas refrigerant) of the refrigerant separated into gas and liquid phases in the accumulator 120 is returned to the compressor 102.

[0058] The other branched refrigerant is throttled and expanded by the second expansion valve 126 to become a medium-temperature, medium-pressure atomized refrigerant, and then heat is exchanged by the internal heat exchanger 122 as it passes through the second flow path 142. That is, heat exchange takes place between the refrigerant flowing through the second flow path 142 and the high-temperature refrigerant flowing through the first flow path 141. At this time, the refrigerant flowing through the second flow path 142 (bypass passage 130, third refrigerant circulation passage) is heated by the heat exchange and introduced into the intermediate port 102c in a state of increased dryness. Therefore, together with the refrigerant circulating through the second refrigerant circulation passage and introduced from the intake port 102a, the discharge flow rate in the compressor 102 can be increased, and the heat exchange in the auxiliary condenser 104, i.e., the heating performance, can be improved.

[0059] On the other hand, the refrigerant flowing through the first flow path 141 (second refrigerant circulation passage) is cooled by heat exchange, becoming a liquid refrigerant with a large degree of supercooling, and is then guided to the first expansion valve 124. As a result, when it expands in the first expansion valve 124, the enthalpy becomes lower than during normal heating operation, which can improve the heat exchange efficiency (heat absorption performance) with the outside air.

[0060] As described above, in this embodiment, the accumulator unit 108 is configured to house the accumulator 120 inside the internal heat exchanger 122. Furthermore, the bodies of the first expansion valve 124 and the second expansion valve 126 are integrally provided with the housing 10 of the internal heat exchanger 122, in other words, they constitute part of the housing of the accumulator unit 108. As a result, piping and other connections between each component are unnecessary, enabling a simple and compact refrigeration cycle. This embodiment makes it possible to save space in a refrigeration cycle employing a two-stage compression cycle. It also contributes to reducing refrigerant leakage in the refrigerant circulation passage.

[0061] [Second Embodiment] Figure 6 is a system configuration diagram of a vehicle air conditioning and heating system according to the second embodiment. This embodiment differs from the first embodiment in that the heating and cooling system 200 has a refrigerant circulation circuit 201 and coolant circulation circuits 202 and 203, employing a so-called water-cooled refrigeration cycle. The heater core 204 located in the coolant circulation circuit 202 provides the heating function, and the cooler core 206 located in the coolant circulation circuit 203 provides the cooling function. The coolant circulation circuit 203 has a first water circulation path 212, and the coolant circulation circuit 202 has a second water circulation path 214. In the indoor air conditioning unit 112, the blower 113, cooler core 206, and heater core 204 are arranged from the upstream side in the direction of airflow. An air mix door 114 is provided upstream of the heater core 204. In this embodiment, 124 is an electric valve (electronic expansion valve), similar to the second expansion valve 126, for example, as described in Japanese Patent Application Publication No. 2023-53708.

[0062] The heating and cooling system 200 includes a water-refrigerant condenser 208 for heat exchange between the refrigerant circulation circuit 201 and the coolant circulation circuit 202, and a water-refrigerant evaporator 210 for heat exchange between the refrigerant circulation circuit 201 and the coolant circulation circuit 203. The refrigerant circulation circuit 201 is constructed by connecting the compressor 102, the water-refrigerant condenser 208, the accumulator unit 108, and the water-refrigerant evaporator 210 with piping. The water-refrigerant condenser 208 functions as the "first heat exchanger," and the water-refrigerant evaporator 210 functions as the "second heat exchanger."

[0063] The outlet (discharge port 102b) of the compressor 102 is connected to the inlet of the water-refrigerant condenser 208 via the first passage 131. The second passage 132 is connected to the outlet of the water-refrigerant condenser 208. The second passage 132 branches off at branching point P1 and is connected to the inlet ports 108a and 180b of the accumulator unit 108. The outlet port 108d of the accumulator unit 108 is connected to the inlet of the water-refrigerant evaporator 210 via the third passage 133. The outlet of the water-refrigerant evaporator 210 is connected to the inlet port 108c of the accumulator unit 108 via the fourth passage 134.

[0064] The coolant circulation circuit 202 is constructed by connecting a water-refrigerant condenser 208, a heater core 204, and a heat exchanger 220 (radiator) with piping. Heat exchange occurs as the coolant circulates through the coolant circulation circuit 202. The coolant circulation circuit 202 is equipped with a pump 222 for circulating the coolant. The coolant may be an aqueous solution (cooling water) mainly composed of, for example, ethylene glycol or propylene glycol. A fan 221 is positioned opposite the heat exchanger 220. The fan 221 is driven to introduce outside air into the engine compartment, allowing heat exchange to occur between the coolant flowing through the heat exchanger 220 and the outside air.

[0065] A branching point P21 is provided between the heater core 204 and the radiator 220 in the second water circulation path 214, and a connection point P22 is provided between the radiator 220 and the pump 222. A bypass passage 215 is provided connecting the branching point P21 and the connection point P22. A three-way valve 226 is installed at the connection point P22. In the second water circulation path 214, a first circulation path is formed so that the coolant circulates so that it flows through the radiator 220, and a second circulation path is formed so that the coolant circulates so that it bypasses the radiator 220 (i.e., flows through the bypass passage 215), and these two paths can be switched off. By operating the three-way valve 226, one of the first and second circulation paths is opened and the other is closed.

[0066] Meanwhile, the coolant circulation circuit 203 is constructed by connecting a water-refrigerant evaporator 210, a water-air evaporator 230, and a cooler core 206 with piping. Heat exchange occurs as the coolant circulates through the coolant circulation circuit 203. The coolant circulation circuit 203 is equipped with a pump 224 for circulating the coolant. A fan 231 is positioned opposite the radiator 230. The fan 231 is driven to introduce outside air into the engine compartment, allowing heat exchange to occur between the coolant flowing through the radiator 230 and the outside air.

[0067] A branch point P23 and a connection point P24 are provided downstream of the water-refrigerant evaporator 210 in the first water circulation path 212, and a bypass passage 232 is provided connecting branch point P23 and connection point P24. A three-way valve 234 is installed at branch point P23. Furthermore, a branch point P25 is provided downstream of connection point P24 in the first water circulation path 212, and a connection point P26 is provided between the cooler core 206 and the pump 224. A bypass passage 236 is provided connecting branch point P25 and connection point P26. A three-way valve 238 is installed at branch point P25.

[0068] In the first water circulation path 212, a third circulation path is formed in which the coolant flows through the cooler core 206 while bypassing the radiator 230, and a fourth circulation path is formed in which the coolant flows through the radiator 230 while bypassing the cooler core 206 (i.e., flowing through the bypass passage 236). One of the third and fourth circulation paths is opened and the other is closed by the operation of the three-way valves 234 and 238.

[0069] Next, the operation of the refrigeration cycle in this embodiment will be described. Figures 7 and 8 illustrate the operation of the heating and cooling system 200. Figure 7(A) shows the cooling operation state, and Figure 7(B) shows the normal heating operation state. Figure 8 shows the specific heating operation state. The thick lines and arrows in the figures indicate the flow of refrigerant or coolant. The "×" symbols in the figures indicate that the flow of refrigerant or coolant is blocked.

[0070] (Air conditioning operation) As shown in Figure 7(A), during cooling operation, the first expansion valve 124 in the refrigerant circulation circuit 201 is in an open state (slightly open), and the second expansion valve 126 is in a closed state. In the coolant circulation circuit 202, the bypass passage 215 is blocked by the three-way valve 226, and the first circulation path is opened. The air mix door 114 is closed. On the other hand, in the coolant circulation circuit 203, the bypass passage 232 is blocked by the three-way valve 234, and the bypass passage 236 is blocked by the three-way valve 238, thereby opening the third circulation path.

[0071] In the refrigerant circulation circuit 201, the refrigerant discharged from the compressor 102 is condensed (heat is released) by passing through the water-refrigerant condenser 208. At this time, heat exchange takes place between the refrigerant circulation circuit 201 and the coolant circulation circuit 202.

[0072] The refrigerant discharged from the water-refrigerant condenser 208 is throttled and expanded in the first expansion valve 124 and introduced into the water-refrigerant evaporator 210. The refrigerant evaporates as it passes through the water-refrigerant evaporator 210. During this process, heat exchange occurs between the refrigerant circulation circuit 201 and the coolant circulation circuit 203. The refrigerant discharged from the water-refrigerant evaporator 210 is separated into gas and liquid phases in the accumulator 120, and its gaseous phase component is guided to the suction port 102a of the compressor 102.

[0073] At this time, in the coolant circulation circuit 202, the coolant heated in the water-refrigerant condenser 208 is supplied to the heater core 204, but since the air mix door 114 is closed, no heat exchange occurs with the air inside the vehicle. This coolant is then released by passing through the radiator 220 and is returned to the water-refrigerant condenser 208. In other words, the heat of condensation in the water-refrigerant condenser 208 is discharged into the atmosphere by the radiator 220. Meanwhile, in the coolant circulation circuit 203, the coolant cooled in the water-refrigerant evaporator 210 is supplied to the cooler core 206, where heat exchange occurs and the air inside the vehicle is cooled.

[0074] (Normal heating operation) As shown in Figure 7(B), during normal heating operation, the first expansion valve 124 in the refrigerant circulation circuit 201 is open (slightly open), and the second expansion valve 126 is closed. In the coolant circulation circuit 202, the bypass passage 215 is opened by the three-way valve 226, opening the second circulation path. The air mix door 114 is opened. On the other hand, in the coolant circulation circuit 203, the bypass passage 232 is opened by the three-way valve 234, and the bypass passage 236 is opened by the three-way valve 238, opening the fourth circulation path. Therefore, the cooler core 206 does not function.

[0075] The refrigerant discharged from the compressor 102 is condensed by passing through the water-refrigerant condenser 208. At this time, heat exchange takes place between the refrigerant circulation circuit 201 and the coolant circulation circuit 202. The coolant flowing through the coolant circulation circuit 202 absorbs heat in the water-refrigerant condenser 208 and releases heat in the heater core 204. As the air mix door 114 is opened wide, heat exchange takes place in the heater core 204, warming the air inside the vehicle. The refrigerant that has passed through the water-refrigerant condenser 208 evaporates by passing through the water-refrigerant evaporator 210, and is separated into gas and liquid phases in the accumulator 120, with the gaseous component (gas refrigerant) being returned to the compressor 102. The coolant flowing through the coolant circulation circuit 203 absorbs heat from the outside as it passes through the radiator 230.

[0076] (Specific heating operation) As shown in Figure 8, during specific heating operation, the first expansion valve 124 in the refrigerant circulation circuit 201 is opened (slightly open), and the second expansion valve 126 is also opened (slightly open). The bypass passage 130 is opened compared to the normal heating state. As with normal heating operation, the bypass passage 215 in the coolant circulation circuit 202 is opened. The bypass passages 232 and 236 in the coolant circulation circuit 203 are opened.

[0077] The refrigerant discharged from the compressor 102 is condensed by passing through the water-refrigerant condenser 208. At this time, heat exchange takes place between the refrigerant circulation circuit 201 and the coolant circulation circuit 202. The coolant flowing through the coolant circulation circuit 202 absorbs heat in the water-refrigerant condenser 208 and releases heat in the heater core 204. As the air mix door 114 is opened wide, heat exchange takes place in the heater core 204, warming the air inside the vehicle. The refrigerant that has passed through the water-refrigerant condenser 208 branches off at branching point P1. One of the branched refrigerants evaporates by passing through the water-refrigerant evaporator 210, and is separated into gas and liquid phases in the accumulator 120, with its gaseous component (gas refrigerant) being returned to the compressor 102. The coolant flowing through the coolant circulation circuit 203 absorbs heat from the outside as it passes through the radiator 230.

[0078] The other branched refrigerant is throttled and expanded by the second expansion valve 126 to become a medium-temperature, medium-pressure atomized refrigerant, which is then subjected to heat exchange by the internal heat exchanger 122. At this time, the refrigerant flowing through the bypass passage 130 (third refrigerant circulation passage) is heated by the heat exchange and introduced into the intermediate port 102c in a state of increased dryness. Therefore, together with the refrigerant circulating through the second refrigerant circulation passage and introduced from the intake port 102a, the discharge flow rate in the compressor 102 can be increased, improving the heat exchange performance in the water-refrigerant condenser 208 and, consequently, the heat exchange performance in the heater core 204. In other words, heating performance can be improved.

[0079] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these specific embodiments, and various modifications are possible within the scope of the technical concept of the present invention.

[0080] [Differentiation] Figures 9 and 10 illustrate the configuration around the accumulator unit in a modified example. Figure 9 is an assembly diagram of the heat exchange module, and Figure 10 is an exploded view. As shown in Figure 9, in this modified example, a heat exchange module 300 is configured which integrates the accumulator unit 308, the water-refrigerant condenser 208, and the water-refrigerant evaporator 210.

[0081] As shown in Figure 10, the accumulator unit 308 has an inlet port 108c (third inlet port) at the center of the lower end of the housing 10. That is, in addition to the first refrigerant passage 34 and the second refrigerant passage 36, the body 332 of the first expansion valve 124 is provided with a third refrigerant passage 38, and the third refrigerant passage 38 has an inlet port 108c. A connecting pipe 320 is provided inside the housing 10 to connect the upper space (gas phase section GA) of the accumulator 120 to the inlet port 108c. The connecting pipe 320 extends vertically inside the housing 10, penetrates the rectifier plate 16, and its upper end opens above the rectifier plate 16. An external pipe 24 connected to the intermediate port 102c of the compressor 102 is connected to the outlet port 108e of the accumulator unit 308.

[0082] Three fittings are provided protruding from one side of the water-refrigerant condenser 208, each having a first outlet port 208a, a second outlet port 208b, and an inlet port 208c. A branching point P1 is provided inside the water-refrigerant condenser 208. One of the passages branching off at branching point P1 connects to the first outlet port 208a, and the other passage connects to the second outlet port 208b. External piping (not shown) extending from the discharge port 102b is connected to the inlet port 208c.

[0083] The water-refrigerant condenser 208 is connected to the accumulator unit 308 by having its first outlet port 208a connected to the inlet port 108a and its second outlet port 208b connected to the inlet port 108b. In other words, the water-refrigerant condenser 208 is connected to the accumulator unit 308 via the second expansion valve 126.

[0084] On the other hand, two fittings are provided protruding from one side of the water-refrigerant evaporator 210, each having an inlet port 210a and an outlet port 210b. The water-refrigerant evaporator 210 is connected to the accumulator unit 308 by having its inlet port 210a connected to the outlet port 108d and its outlet port 210b connected to the introduction port 108c. In other words, the water-refrigerant evaporator 210 is connected to the accumulator unit 308 via the first expansion valve 124.

[0085] This configuration provides a heat exchange module 300 in which an accumulator 120, an internal heat exchanger 122, a first expansion valve 124, and a second expansion valve 126 are integrated into a single unit. As a result, piping and other connections between these components are unnecessary. This enables space savings in the refrigeration cycle. It also contributes to reducing refrigerant leakage in the refrigerant circulation passage. This is particularly effective when using highly flammable natural refrigerants such as propane.

[0086] [Other variations] In the first embodiment described above, as shown in Figure 1, a motor-driven electric valve was exemplified as the third expansion valve 128, but a solenoid-driven electromagnetic valve may also be used. In that case, the small opening degree is controlled by the electromagnetic valve. Alternatively, a temperature-controlled expansion valve that operates by sensing the temperature and pressure of the refrigerant may also be used.

[0087] In the above embodiment, a cylindrical (circular cross-section) tank 12 was used as the accumulator 120. Therefore, an example was shown in which the internal piping 30 was made cylindrical (circular in plan view) to match the shape of the accumulator 120, and the housing 10 of the accumulator unit 108 was also cylindrical. In a modified example, a tank with a polygonal cross-section may be used as the accumulator. In that case as well, the internal piping is wrapped around the outer surface of the accumulator. The housing of the accumulator unit may also be made coaxial (concentric) with the accumulator, for example, by making the cross-section polygonal.

[0088] In the above embodiment, an example was shown in which the accumulator unit 108 is assembled as an integral unit comprising an accumulator 120, an internal heat exchanger 122, a first expansion valve 124, and a second expansion valve 126. In a modified example, at least one of the first expansion valve 124 and the second expansion valve 126 may be separated from the accumulator unit and placed in the refrigerant circulation passage.

[0089] It should be noted that the present invention is not limited to the embodiments and modifications described above, and the components can be modified and implemented without departing from the spirit of the invention. Various inventions may be formed by appropriately combining the multiple components disclosed in the embodiments and modifications described above. In addition, some components may be deleted from all the components shown in the embodiments and modifications described above. [Explanation of Symbols]

[0090] 10 Housing, 12 Tank, 14 Refrigerant piping, 16 Rectifier plate, 30 Internal piping, 100 Heating and cooling system, 102 Compressor, 102a Intake port, 102b Discharge port, 102c Intermediate port, 104 Auxiliary condenser, 106 Outdoor heat exchanger, 108 Accumulator unit, 110 Evaporator, 112 Indoor air conditioning unit, 120 Accumulator, 122 Internal heat exchanger, 124 First expansion valve, 126 Second expansion valve, 128 Third expansion valve, 130 Bypass passage, 141 First flow path, 142 Second flow path, 143 Third flow path, 150 Check valve, 152 On / off valve, 160 Control unit, 200 Heating and cooling system, 201 Refrigerant circulation circuit, 202 Coolant circulation circuit, 203 Coolant circulation circuit, 204 Heater core, 206 Cooler core, 208 Water-refrigerant condenser, 208a First outlet port, 208b Second outlet port, 208c Inlet port, 210 Water-refrigerant evaporator, 210a Inlet port, 211b Outlet port, 212 First water circulation path, 214 Second water circulation path, 215 Bypass passage, 220 Radiator, 222 Pump, 224 Pump, 226 Three-way valve, 230 Radiator, 232 Bypass passage, 234 Three-way valve, 236 Bypass passage, 238 Three-way valve, 300 Heat exchange module, 308 Accumulator unit, 320 Connecting pipe, GA Gas phase section, LA Liquid phase section, P1 Branch point.

Claims

1. A compressor having an intermediate port between an intake port and a discharge port, which compresses the refrigerant introduced from the intake port and the intermediate port and discharges it from the discharge port, A first heat exchanger that dissipates heat from the refrigerant discharged from the compressor, A first expansion valve that expands the refrigerant that has passed through the first heat exchanger, A second heat exchanger that evaporates the refrigerant expanded by the first expansion valve, An accumulator separates the refrigerant that has passed through the second heat exchanger into gas and liquid phases, stores it, and leads the gaseous refrigerant toward the intake port of the compressor, A refrigerant circulation passage is provided that allows the refrigerant discharged from the compressor to circulate through the first heat exchanger, the first expansion valve, the second heat exchanger, and the accumulator in sequence, and return to the compressor via the suction port. A bypass passage branches off at a branching point between the first heat exchanger and the first expansion valve in the refrigerant circulation passage, and connects to the intermediate port of the compressor. A second expansion valve is provided in the bypass passage, An internal heat exchanger performs heat exchange between the refrigerant sent to the first expansion valve via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve in the bypass passage. An accumulator unit applied to the refrigeration cycle of a vehicle air conditioning system, comprising: The accumulator and the internal heat exchanger are provided as an integral part of the structure. An accumulator unit characterized in that the refrigerant in the accumulator exchanges heat with the refrigerant sent to the first expansion valve via the branching point.

2. A housing that accommodates the accumulator and has a first inlet port, a first outlet port, a second inlet port, and a second outlet port, An internal pipe is provided within the housing so as to extend along the outer surface of the accumulator and forms a first flow path that connects the first inlet port and the first outlet port, Equipped with, In the housing, a second flow path is formed in the space containing the internal piping, connecting the second inlet port and the second outlet port. The accumulator unit according to claim 1, characterized in that the first flow path constitutes the refrigerant circulation path as an internal heat exchanger, while the second flow path constitutes the bypass path, and heat exchange takes place between the refrigerant flowing through the first flow path and the refrigerant flowing through the second flow path.

3. The accumulator unit according to claim 1 or 2, characterized in that the second expansion valve is integrally provided.

4. The accumulator unit according to claim 3, characterized in that the first expansion valve is further integrally provided.

5. The accumulator unit according to claim 3, characterized in that the second expansion valve is an electronic expansion valve that is opened only when two-stage compression is performed by the compressor.

6. A heat exchange module applicable to a vehicle air conditioning system comprising: a first water circulation path provided with a cooler core for cooling; a second water circulation path provided with a heater core for heating; and a refrigeration cycle that exchanges heat between the first water circulation path and the second water circulation path, respectively. The aforementioned refrigeration cycle is A compressor having an intermediate port between an intake port and a discharge port, which compresses the refrigerant introduced from the intake port and the intermediate port and discharges it from the discharge port, A first heat exchanger that dissipates heat from the refrigerant discharged from the compressor and exchanges heat with the second water circulation path, A first expansion valve that expands the refrigerant that has passed through the first heat exchanger, A second heat exchanger that evaporates the refrigerant expanded by the first expansion valve and exchanges heat with the first water circulation path, An accumulator separates the refrigerant that has passed through the second heat exchanger into gas and liquid phases, stores it, and leads the gaseous refrigerant toward the intake port of the compressor, A refrigerant circulation passage is provided that allows the refrigerant discharged from the compressor to circulate through the first heat exchanger, the first expansion valve, the second heat exchanger, and the accumulator in sequence, and return to the compressor via the suction port. A bypass passage branches off at a branching point between the first heat exchanger and the first expansion valve in the refrigerant circulation passage, and connects to the intermediate port of the compressor. A second expansion valve is provided in the bypass passage, An internal heat exchanger performs heat exchange between the refrigerant sent to the first expansion valve via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve in the bypass passage. Equipped with, A heat exchange module characterized in that the accumulator, the internal heat exchanger, the first expansion valve, and the second expansion valve are provided as an integral part of the module.

7. Furthermore, the heat exchange module according to claim 6 is characterized in that the first heat exchanger and the second heat exchanger are provided integrally.

8. A housing that accommodates the accumulator and has a first inlet port, a first outlet port, a second inlet port, a second outlet port, a third inlet port, and a third outlet port, An internal pipe is provided within the housing so as to extend along the outer surface of the accumulator and forms a first flow path that connects the first inlet port and the first outlet port, A connecting pipe extending within the housing and connecting the third introduction port and the upper space of the accumulator, Equipped with, The bodies of the first expansion valve and the second expansion valve are integrally provided in the housing. In the housing, a second flow path is formed in the space containing the internal piping, connecting the second inlet port and the second outlet port. As the internal heat exchanger, the first flow path constitutes the refrigerant circulation passage, while the second flow path constitutes the bypass passage, and heat exchange takes place between the refrigerant flowing through the first flow path and the refrigerant flowing through the second flow path. The inlet port of the second heat exchanger is connected to the first outlet port, The outlet port of the second heat exchanger is connected to the third inlet port, The heat exchange module according to claim 7, characterized in that the refrigerant that has passed through the accumulator is discharged from the third discharge port toward the compressor.

9. The refrigerant passage of the first heat exchanger includes the branching point and has a first outlet port and a second outlet port for discharging the refrigerant branched off at the branching point, The first exit port is connected to the first input port, The heat exchange module according to claim 8, characterized in that the second outlet port is connected to the second inlet port.

10. A refrigeration cycle for a vehicle air conditioning and heating system, A compressor having an intermediate port between an intake port and a discharge port, which compresses the refrigerant introduced from the intake port and the intermediate port and discharges it from the discharge port, A first heat exchanger that dissipates heat from the refrigerant discharged from the compressor, A first expansion valve that expands the refrigerant that has passed through the first heat exchanger, A second heat exchanger that evaporates the refrigerant expanded by the first expansion valve, An accumulator separates the refrigerant that has passed through the second heat exchanger into gas and liquid phases, stores it, and leads the gaseous refrigerant toward the intake port of the compressor, A refrigerant circulation passage is provided that allows the refrigerant discharged from the compressor to circulate through the first heat exchanger, the first expansion valve, the second heat exchanger, and the accumulator in sequence, and return to the compressor via the suction port. A bypass passage branches off at a branching point between the first heat exchanger and the first expansion valve in the refrigerant circulation passage, and connects to the intermediate port of the compressor. A second expansion valve is provided in the bypass passage, An internal heat exchanger performs heat exchange between the refrigerant sent to the first expansion valve via the branching point in the refrigerant circulation passage and the refrigerant that has passed through the second expansion valve in the bypass passage. Equipped with, The accumulator and the internal heat exchanger are provided as an integrated accumulator unit. A refrigeration cycle characterized in that the refrigerant in the accumulator exchanges heat with the refrigerant sent to the first expansion valve via the branching point.

Images