JP2011153825A - Refrigerating air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem on degradation of operation efficiency when a load medium of high temperature is heated, as a refrigerant state at an outlet of a radiator is gas, and a gas-liquid two phase refrigerant can not be prepared even when the refrigerant is decompressed, a function of a heat pump can not be exerted. <P>SOLUTION: In an expanding section 13a, a part of the refrigerant at the outlet of the radiator 2 flows therein, is expanded and decompressed to generate power, and flows out from the expanding section 13a. In a compressing section 13b, a saturated gas refrigerant coming out from an accumulator 7 flows therein, is compressed for pressure rising, and flows out from the compressing section 13b. The refrigerants flowing out from the expanding section 13a and the compressing section 13b are joined, and flow into a low pressure side of a high/low pressure heat exchanger 4. Thus a pressure of the refrigerant decompressed to a pressure Pe lower than a saturated pressure to an outside air temperature in a bypass circuit 8 can be raised to the saturated pressure or more to the outside air temperature by an expanding machine 13. The compression power of the compressor 1 can be reduced in comparison with a case when the pressure of the refrigerant of the bypass circuit 8 is raised by the compressor 1 from the state of pressure Pe, and the operation of high efficiency can be performed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a refrigeration air conditioner, and more particularly to a refrigeration air conditioner that includes a device that recovers expansion power such as an ejector and that generates a high-temperature load medium such as hot water.

As a conventional refrigeration air conditioner that generates high temperatures, carbon dioxide is used as a refrigerant, the temperature of the refrigerant is kept within a predetermined range by a cooler, the accumulator can be eliminated by suppressing the amount of excess refrigerant, and miniaturization can be achieved. it can. There are some which boil low-temperature water or air in a duct to a high temperature (for example, see Patent Document 1).
Further, as a refrigeration air conditioner to which an ejector is applied, there is one provided with a bypass circuit that branches a part of the refrigerant flowing into the ejector and supplies it to the evaporator (for example, see Patent Document 2). In addition, there is a type in which an ejector is used as a gas pump and two evaporators are operated simultaneously or independently at different temperatures (for example, see Patent Document 3).

Japanese Patent Laying-Open No. 2004-3825 (page 4-5, FIG. 1) JP 2007-3166 (page 7-8, FIG. 1) JP 2004-257694 A (page 4-7, FIG. 1)

However, the conventional refrigeration air conditioner (Patent Document 1) has the following problems. In the conventional apparatus, since operation is performed to boil relatively low-temperature water, the refrigerant is also cooled to a low temperature according to the temperature of the low-temperature water. Therefore, when the refrigerant at the outlet of the radiator is depressurized, it becomes a gas-liquid two-phase state, and if it is depressurized to a pressure that becomes a saturation temperature at which heat can be collected from outside air, heat can be collected by the evaporator, and it can function as a heat pump. Highly efficient operation was carried out. However, when the feed water temperature is high, for example, when the operation is performed to boil up to 75 ° C. with 70 ° C. feed water, the refrigerant temperature at the radiator outlet is higher than the feed water temperature and is 70 ° C. or more. Even if the pressure is reduced from this state, it does not become a gas-liquid two-phase, and the pressure is reduced in the gas state. When the pressure is reduced in the gas state, the refrigerant temperature at the same pressure becomes higher than that in the gas-liquid two-phase state, so that the amount of pressure reduction required from the outside air to the temperature at which heat can be collected increases. Therefore, there has been a problem that the compression work when the refrigerant at the outlet of the evaporator is compressed again is increased by the amount of decompression, and the operation efficiency is lowered. Further, when the pressure is reduced in the gas state, the amount of heat that can be reheated from the outside air after the pressure reduction is proportional to the gas specific heat × the gas temperature change. Therefore, in order to increase the amount of heat reheated from the outside air, it is necessary to lower the refrigerant temperature after depressurization from the outside air temperature and increase the temperature difference from the outside air. As a result, there was a problem that the compression work increased and the operating efficiency decreased. The pressure reduction range can also be reduced to reduce the compression power, but in this case, the amount of heat collected from the outside air becomes 0, the function as a heat pump cannot be obtained, and the work that the refrigerant receives in the compressor There is a problem that the operation is performed to dissipate the amount of heat corresponding to the heating, and the COP, which is the operation efficiency, is reduced to 1, which is equivalent to the heater. Further, since the compression ratio at the time of compression increases as the amount of decompression increases, the compressor discharge temperature rises. Depending on the situation, the operation of further cooling the decompressed gas refrigerant and lowering the temperature of the refrigerant sucked into the compressor is required depending on the situation, so that the COP becomes smaller than 1 and the operation efficiency further decreases. There was a problem.
In order to solve this problem, it is necessary to operate the refrigerant at a condensation temperature of 70 ° C. or higher to realize the liquefaction of the refrigerant in the radiator, but for this purpose, it is more than the high pressure used in a normal refrigeration cycle. It is necessary to operate at high pressure. From the problem of pressure resistance of normal equipment and the arrangement of the high-pressure gas safety law, the design pressure of the apparatus is often set to a saturation temperature of the refrigerant with respect to the design pressure at 65 ° C. The operation at about 75 ° C. is required, and accordingly, the design pressure needs to be set high, and the device needs to be designed so that the pressure strength increases. In order to ensure pressure resistance, it is necessary to increase the thickness of pipes, shells, and containers, resulting in a problem that the material cost of the apparatus increases.

  Further, in the case of another conventional refrigeration air conditioner (Patent Document 2), there are the following problems. Since the refrigerant in the same state as the refrigerant supplied to the evaporator is supplied to the ejector, the refrigerant decompressed by the ejector is in a gas-liquid two-phase state. In the ejector, the kinetic energy obtained by increasing the speed at the time of decompression is converted to pressure energy, so that the pressure of the sucked refrigerant is increased. However, when the gas-liquid two-phase refrigerant flows at high speed, The speed is high and the speed of the dense liquid phase is slow. Since a speed difference occurs between the gas and liquid, friction is generated at the gas-liquid interface, and the kinetic energy is lost by the amount lost by this friction, and the amount that can be converted into pressure energy is reduced. That is, since the ejector is used in a gas-liquid two-phase state in the ejector, there is a problem that the power recovery efficiency in the ejector is lowered and the operation efficiency is lowered.

  Further, in the case of another conventional refrigeration air conditioner (Patent Document 3), there are the following problems. In the conventional apparatus, the refrigerant discharged from the compressor is supplied to the ejector, and the ejector is used as a pump. However, when heating a high-temperature load medium such as in a hot water supply operation, the refrigerant discharged from the compressor has a heating capacity because it is higher than the temperature of the load medium, but the heating capacity of the refrigerant is not utilized. There was a problem that wasted.

  This invention was made in order to solve the above-mentioned subject, and when heating a high-temperature load medium, while achieving the function of a heat pump, it aims at obtaining the refrigerating air-conditioner which realizes high efficiency operation. To do. In particular, high efficiency operation is realized by realizing the function of the heat pump when using a load medium in the vicinity of the upper limit condensing temperature defined by the saturation temperature according to the design pressure of the device, or when a load medium higher than that temperature is used. It is intended to be a device.

  The refrigeration air conditioner according to the present invention includes a refrigeration cycle in which a first compressor, a radiator, an expansion unit, and a high-low pressure heat exchanger low-pressure unit are sequentially connected in an annular manner, and between the radiator and the expansion unit. A bypass circuit that branches and joins between the expansion section and the low pressure section of the high / low pressure heat exchanger, and on the bypass circuit, a high flow that exchanges heat with the refrigerant flowing through the low pressure section of the high / low pressure heat exchanger. A low-pressure heat exchanger, a high-pressure unit, a decompression device, an evaporator, and a second compressor driven by the expansion unit are sequentially provided, and when the radiator heats a load medium having a temperature higher than a predetermined temperature, the compressor The refrigerant from the refrigerant is cooled and output in a gas state, the expansion unit inputs the refrigerant from the radiator in a gas state, and the second compressor supplies the refrigerant from the evaporator in a gas state. Input.

  In the present invention, it becomes possible to heat the gas refrigerant flowing into the high-low pressure heat exchanger that is higher in temperature than the outside air by the heat obtained from the outside air via the bypass circuit and the high-low pressure heat exchanger. In the operation of heating the medium, the refrigeration cycle can be made to function as a heat pump even under operating conditions in which the radiator outlet becomes gas, and a highly efficient operation can be realized. In addition, the refrigerant whose pressure is reduced to a pressure lower than the saturation pressure with respect to the outside air temperature in the bypass circuit can be increased to the saturation pressure or more with respect to the outside air temperature. Therefore, compared with the case where the pressure of the refrigerant in the bypass circuit is increased by the compressor from a pressure lower than the saturation pressure with respect to the outside air temperature, the compression power of the compressor can be reduced, and a highly efficient operation can be realized.

1 is a circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 1 of the present invention. It is the figure which showed the structure and pressure change of the ejector of the refrigerating and air-conditioning apparatus which shows Embodiment 1 of this invention. It is a figure which shows the correlation of the pressure and enthalpy of the refrigerating air-conditioning apparatus which shows Embodiment 1 of this invention. It is a flowchart which shows the control action of the refrigerating air conditioner which shows Embodiment 1 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus which shows Embodiment 2 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus which shows Embodiment 3 of this invention. It is a circuit diagram of the refrigerating and air-conditioning apparatus which shows Embodiment 4 of this invention.

Embodiment 1 FIG.
A first embodiment of the present invention is shown in FIG. FIG. 1 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus according to the present invention. The refrigerant circuit includes a compressor 1, a radiator 2 acting as a load-side heat exchanger for heating hot water, an ejector 3, a high-low pressure heat exchanger 4, and a reduced pressure. It comprises an expansion valve 5 acting as a device, an evaporator 6 acting as a heat source side heat exchanger, and an accumulator 7, which are connected in a ring shape as shown.
That is, the refrigeration cycle is configured in the order of the low pressure side (lower side in FIG. 1) of the compressor 1, the radiator 2, the ejector 3, and the high / low pressure heat exchanger 4, and the refrigerant that has exited the low pressure side of the high / low pressure heat exchanger 4. Is returned to the compressor 1 suction side. Further, a part of the refrigerant distributed at the outlet of the radiator 2 is connected to the high pressure side (the upper side in FIG. 1) of the high / low pressure heat exchanger 4, the expansion valve 5, the evaporator 6, and the accumulator 7 in this order. The saturated gas refrigerant flowing through the accumulator 7 is returned to the suction portion of the ejector 3.
The compressor 1 is a type in which the rotation speed is controlled by an inverter and the capacity is controlled. The evaporator 6 exchanges heat with the air around the refrigeration air conditioner conveyed by the blower. The ejector 3 has a structure in which the throttle opening at the expansion portion is variable. The expansion valve 5 is an electronic expansion valve whose opening degree is variably controlled. The radiator 2 and the high / low pressure heat exchanger 4 are plate heat exchangers, and the heat exchanger 2 performs heat exchange between the load side heat medium such as water and brine to be conveyed and the refrigerant. In the high / low pressure heat exchanger 4, the high / low pressure refrigerant exchanges heat, and heat is transferred from the high pressure side to the low pressure side. Further, the high-pressure channel and the low-pressure channel have a counterflow configuration in which one outlet and one inlet are close to each other. The accumulator 7 has a gas-liquid separation and excess refrigerant storage function, and the saturated gas refrigerant after the gas-liquid separation by the accumulator 7 flows out of the accumulator 7 and is sucked into the ejector 3. For example, R410A is used as the refrigerant of the refrigeration air conditioner. The design pressure of this device is set to 4.28 MPa, the saturation temperature for that pressure is 65 ° C., and the upper limit of the condensation temperature is 65 ° C. even if the high pressure is operated at the highest pressure, the design pressure.

In the apparatus, a pressure sensor 9a is provided on the suction side of the compressor 1 and a pressure sensor 9b is provided on the discharge side of the compressor 1, and the refrigerant pressure at the installation location is measured.
Also, the temperature sensor 10a is the compressor 1 suction side, the temperature sensor 10b is the compressor 1 discharge side, the temperature sensor 10c is the radiator 2 outlet, the temperature sensor 10d is the high pressure side outlet of the high / low pressure heat exchanger 4, and the temperature sensor 10e is evaporated. A temperature sensor 10f is provided at the inlet of the heat exchanger 6 at the outlet of the ejector 3 (low pressure side inlet of the high / low pressure heat exchanger 4), and measures the refrigerant temperature at each installation location. Further, the temperature sensor 10g is provided at the load-side heat medium flow path inlet of the radiator 2, and the temperature sensor 10h is provided at the load-side heat medium flow path outlet of the radiator 2, and the temperature of the load-side heat medium here is measured. To do. A temperature sensor 10i is provided to measure the outside air temperature around the apparatus.

  In addition, the apparatus is provided with a measurement control device 11, which is based on measurement information such as the pressure sensor 9 and the temperature sensor 10 and the operation content instructed by the user of the refrigeration air conditioner. The operation method of the compressor 1, the blower air volume of the evaporator 6, the throttle opening of the ejector 3, the opening of the expansion valve 5, and the like are controlled. The measurement control device 11 is composed of a processor such as a microcomputer or a DSP.

  Next, the structure of the ejector 3 in this refrigeration air conditioner will be described. FIG. 2 is a diagram showing the relationship between the structure of the ejector used in the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention and the pressure change. FIG. 2 (a) shows the structure of the ejector 3. 2 (b) shows the pressure distribution corresponding to the refrigerant flow direction position of the ejector 3 in FIG. 2 (a). 2B, the horizontal axis represents the refrigerant flow direction position of the ejector 3 in FIG. 2A, and the vertical axis represents the pressure at each position of the ejector 3. In FIG. In the figure, the ejector 3 is composed of a needle part 42, an electromagnetic coil part 41 for driving the needle part 42, a nozzle part 43, a mixing part 44, and a diffuser part 45. The nozzle part 43 further includes a decompression part 43a and a nozzle throat part 43c. And the divergent portion 43b. Therefore, the ejector 3 of the present embodiment can change the flow path area of the nozzle throat portion 43c by driving (moving) the needle portion 42 in the axial direction by the electromagnetic coil portion 41 in response to a command from the measurement control device 11. Since this is a possible structure, the ejector has a throttle mechanism with a variable throttle opening.

  The ejector 3 decompresses and expands the refrigerant E1 having the pressure P1, which is a driving flow, by the decompression unit 43a (X1 to X2) to obtain the sound velocity of the pressure P2 by the nozzle throat 43c (X2), and further by the divergent part 43b (X2 to X3) The pressure is reduced to a pressure P3 as a supersonic speed. At this time, the gas refrigerant E4 is sucked from the suction part inlet 3a of the surrounding gas refrigerant, and the sucked gas refrigerant flows out of the divergent part 43b in the suction mixing part (X3 to X4) and becomes supersonic. To the refrigerant E2, and the mixed refrigerant E2 recovers the pressure in the mixing unit 44 (X4 to X5) to the state of the pressure P4, and further increases to the pressure P5 in the diffuser unit 45 (X5 to X6). And then spill.

  Next, the operation | movement operation | movement in this refrigeration air conditioner is demonstrated based on FIGS. 1-3. FIG. 3 is a diagram showing the relationship between the pressure and enthalpy of the refrigerating and air-conditioning apparatus showing Embodiment 1 of the present invention, in which the horizontal axis represents enthalpy and the vertical axis represents pressure. Here, the refrigerating and air-conditioning apparatus according to the present embodiment performs an operation of exchanging heat between the load-side heat medium such as water or brine to be conveyed and the refrigerant, and collecting heat from, for example, outside air having a temperature of 5 ° C. as a heat source. The water flowing at a temperature of 70 ° C. is heated to 75 ° C. to give the heat. Since the inlet water temperature of 70 ° C. is higher than the saturation temperature of 65 ° C. with respect to the aforementioned design pressure, heat cannot be exchanged while condensing the refrigerant when heating the water, and the refrigerant remains in a high temperature gas state. Heat exchange.

The state change of the refrigerant in the refrigeration air conditioner is as follows. First, the high-temperature / high-pressure gas refrigerant R1 (pressure Pd: 4 MPa, temperature 118 ° C.) discharged from the compressor 1 is cooled while the water is radiated to the water by the radiator 2 to heat the water, and the temperature decreases. (Pd: 4 MPa, temperature 71 ° C.).
A part of the refrigerant exiting the radiator 2 (24% of the whole) is branched and flows into the bypass circuit 8, and a large amount of the remaining refrigerant (76% of the whole) flows into the ejector 3. The refrigerant that has flowed into the ejector 3 becomes a saturated gas having a dryness of about 1 in the state R3 (pressure Pe: 0.8 MPa, temperature 0 ° C.) at the outlet of the nozzle portion 43 (position X3 in FIG. 2). Inflow. After mixing with the refrigerant gas flowing out from the accumulator 7 of R4 (pressure Pe: 0.8 MPa, temperature 0 ° C.) flowing in from the gas refrigerant suction section inlet 3a of the ejector 3 in the mixing section 44, R5 (pressure Pe: 0. The refrigerant that has reached a state of 8 MPa and a temperature of 0 ° C. recovers its pressure from Pe to Ps by the diffuser 45, and enters a state of R6 (pressure Ps: 2.0 MPa, temperature of 38 ° C.).
The refrigerant that has flowed out of the ejector 3 flows into the low-pressure side of the high-low pressure heat exchanger 4 and is heated while exchanging heat with the high-pressure refrigerant flowing in the bypass circuit 8, and is in a state R7 (pressure Ps: 2.0 MPa, temperature 66 ° C. ) And is sucked into the compressor 1.

  On the other hand, the refrigerant flowing through the bypass circuit 8 flows into the high-pressure side inlet of the high-low pressure heat exchanger 4, exchanges heat with the refrigerant exiting the ejector 3, cools and condenses, and the state R8 (pressure Pd: 4.0 MPa, It becomes a liquid refrigerant having a temperature of 51 ° C. Thereafter, the liquid refrigerant is depressurized by the expansion valve 5 to become a low dryness two-phase refrigerant in the state R9 (pressure Pe: 0.8 MPa, temperature 0 ° C.), and then flows into the evaporator 6. Heat is transferred from outside air at a temperature of 5 ° C., heated and evaporated to become a saturated gas in a state R4 (pressure Pe: 0.8 MPa, temperature 0 ° C.), and is sucked into the ejector 3 through the accumulator 7 in that state.

By setting the refrigerant state change as described above, the gas refrigerant that exits the ejector 3 and is sucked into the compressor 1 is heated by the gas refrigerant that flows into the high-pressure side of the high-low pressure heat exchanger 4. The refrigerant flowing through the bypass circuit 8 liquefied by cooling on the high pressure side of the high / low pressure heat exchanger 4 to heat the suction gas of the compressor 1 absorbs heat corresponding to the cooling heat from the outside air by the evaporator 6. Heated. The enthalpy of the refrigerant flowing through the bypass channel is substantially the same before branching (state R2) and before merging (state R4).
Therefore, by using the circuit configuration of the present embodiment, the energy of the bypass circuit 8 flowing through the high-pressure side of the high-low pressure heat exchanger 4 ⇒ the refrigerant of the bypass circuit 8 in which the energy partially indirectly flows from the outside air ⇒ the evaporator 6 ⇒ Gas refrigerant sucked into the compressor 1 flowing on the low pressure side of the high / low pressure heat exchanger 4 is transmitted to the gas refrigerant flowing out of the ejector 3 that is higher in temperature than the outside air. It becomes possible to heat.

  Next, the control operation in this refrigeration air conditioner will be described with reference to FIG. First, the measurement control device 11 operates by setting the rotation speed of the compressor 1, the air flow rate of the evaporator 6, the opening degree of the ejector 3, and the opening degree of the expansion valve 5 to initial values (step S401). Here, the measurement control device 11 determines the initial setting value of the air flow rate of the evaporator 6 based on the outside air temperature detected by the temperature sensor 10i. Since the heat exchange capacity is low when the outside air temperature is relatively low, the high air volume is high. In this case, since the heat exchange capacity is high, the air flow is set to be low.

  And after driving | operating in this state, the measurement control apparatus 11 controls each actuator according to an apparatus operating state. First, the rotation speed of the compressor 1 is controlled so that the outlet water temperature, which is the load-side heat medium temperature at the outlet of the radiator 2 detected by the temperature sensor 10h, becomes a preset target value, for example, 75 ° C. When the rotation speed of the compressor 1 is high, the refrigerant flow rate increases, so that the heating capacity of the apparatus increases, the water is further heated, and the water temperature at the outlet of the radiator 2 rises. On the contrary, when the rotation speed of the compressor 1 is low, the water temperature at the outlet of the radiator 2 is lowered. Therefore, the measurement control device 11 compares the water temperature at the outlet of the radiator 2 with the target value, and increases the rotational speed of the compressor 1 when the water temperature is low, and decreases the rotational speed of the compressor 1 when the water temperature is high ( Steps S402 to S404).

  Next, although it is the ventilation volume of the evaporator 6, the measurement control apparatus 11 operates this ventilation volume by an initial setting value fundamentally. However, the refrigerant pressure Pe in the evaporator 6 increases depending on the operating conditions, and the pressure Pd of the refrigerant discharged from the compressor 1 detected by the pressure sensor 9b may increase with the increase. The discharge refrigerant pressure Pd is compared with the design pressure, and if the discharge refrigerant pressure Pd rises excessively and exceeds the design pressure, control is performed to reduce the air volume for protection of the compressor 1. . Thereby, the refrigerant | coolant pressure Pe in the evaporator 6 falls, the pressure Pd of the compressor 1 discharge refrigerant | coolant can also be lowered | hung with the fall, and protection of the compressor 1 is implement | achieved (step S405).

  Next, the opening degree of the ejector 3 and the opening degree of the expansion valve 5, the measurement control device 11 controls the opening degree based on the heat exchange status in the high-low pressure heat exchanger 4 and the discharge temperature of the compressor 1. Control. Next, the operation at the time of opening control will be described below. First, the flow rate of refrigerant flowing through the ejector 3 changes according to the opening degree of the ejector 3, and the refrigerant flow rate increases as the opening degree increases. Conversely, when the refrigerant flow rate is constant, the pressure difference at the ejector 3 changes according to the opening, and when the opening is small, the pressure difference (Pd at the ejector 3 is compensated for the corresponding decrease in the refrigerant flow rate. -Ps) expands. Similarly, the opening degree of the expansion valve 5 has the same characteristics. When the opening degree is larger, the flow rate of the refrigerant passing through the expansion valve 5 increases. When the flow rate is constant, the smaller the opening degree, The pressure difference (Pd−Pe) increases.

  Therefore, the change of the opening degree of the ejector 3 and the expansion valve 5 with respect to the total opening degree is as follows. In this apparatus, since the refrigerant flow rate is defined by the rotation speed of the compressor 1, when the rotation speed does not change, the refrigerant flow volume is substantially the same. Therefore, the smaller the total opening, the larger the pressure difference between the ejector 3 and the expansion valve 5, but the refrigerant pressure Pe in the evaporator 6 operates so as to realize heat exchange with the outside air temperature. The temperature is almost determined by the outside air temperature, and the change due to the opening degree control is small. Therefore, when the total opening is reduced and the pressure difference is increased, the discharge pressure Pd of the compressor 1 increases. When Pd, which is the discharge pressure of the compressor 1, increases, the compression work in the compressor 1 increases, so the discharge temperature of the compressor 1 also increases.

  Here, considering the heat exchange characteristics of the radiator 2, since the refrigerant changes in the gas state in the radiator 2, the amount of heat that the refrigerant can give to water is determined by the temperature difference of the refrigerant, the specific heat, and the refrigerant flow rate. Is done. Even if the discharge pressure Pd, which is the refrigerant operating pressure in the radiator 2, changes, the change in specific heat and refrigerant flow rate is small. Therefore, the change in temperature difference with the increase or decrease in discharge temperature affects the amount of heat that the refrigerant can give. The temperature difference increases as the discharge temperature increases, and the temperature difference decreases as the discharge temperature decreases. When the compressor 1 conveys the same refrigerant flow rate, the heating capacity increases and the operation efficiency increases as the amount of heat given to the refrigerant at the flow rate increases, so that the measurement control device 11 aims at high-efficiency operation. 2, an operation in which the refrigerant inlet / outlet temperature difference increases, that is, an operation aiming at a high discharge temperature is performed. However, since the discharge temperature has an upper limit temperature allowed for each device such as the compressor 1, the measurement control device 11 performs an operation with the highest discharge temperature within a range in which reliability can be secured below this temperature. For example, when the allowable upper limit temperature of the discharge temperature is 120 ° C., the measurement control device 11 controls the opening degree with the discharge temperature 118 ° C. as the target temperature in consideration of the discharge temperature increase due to the transient fluctuation. As described above, the smaller the total opening, the higher the discharge temperature. Therefore, the current discharge temperature is detected by the temperature sensor 10b (step S406), and the measurement control device 11 determines that the discharge temperature is higher than the target temperature. In order to lower the discharge temperature, the total opening degree is controlled to be large, and when the discharge temperature is lower than the target temperature, the total opening degree is controlled to be small in order to increase the discharge temperature to approach the target value (steps S407 to S408). .

  In addition, although the discharge pressure Pd of the compressor 1 also changes by control of a total opening degree, the upper limit pressure permitted to each apparatus, such as the compressor 1, is prescribed | regulated also with respect to the discharge pressure Pd. Therefore, when the control based on the discharge temperature is performed, if the discharge pressure Pd exceeds the upper limit pressure, the measurement control device 11 controls the total opening largely to suppress the increase in the discharge pressure Pd. .

Next, the change with respect to the ratio of the opening degree of the ejector 3 and the expansion valve 5 is shown below. If the opening ratio is defined as the opening degree of the ejector 3 / the opening degree of the expansion valve 5, the refrigerant flow rate flowing through the ejector 3 increases and the refrigerant flow rate flowing through the bypass circuit 8 decreases as the opening ratio increases.
When the opening ratio increases and the flow rate flowing through the ejector 3 increases, the pressure increase of the suction refrigerant due to the action of the ejector 3 increases, and the pressure Ps of the refrigerant discharged from the ejector 3 increases. Further, since the flow rate of the refrigerant flowing through the bypass circuit 8 is reduced, the amount of heat collected from the outside air is reduced, thereby reducing the amount of heat exchange in the high and low pressure heat exchanger 4 and the amount of heating of the gas refrigerant exiting the ejector 3 is reduced. Decrease.
Conversely, when the opening ratio becomes smaller and the flow rate flowing through the ejector 3 decreases, the pressure increase amount of the suction refrigerant due to the action of the ejector 3 decreases, and the pressure Ps of the refrigerant discharged from the ejector 3 decreases. Further, since the flow rate of the refrigerant flowing through the bypass circuit 8 increases, the amount of heat collected from the outside air increases, thereby increasing the amount of heat exchange in the high / low pressure heat exchanger 4 and the amount of heat of the gas refrigerant exiting the ejector 3 is increased. To increase.

  Even if the opening ratio increases and the flow rate of the bypass circuit 8 decreases, if the enthalpy difference on the high pressure side of the high and low pressure heat exchanger 4 increases by an amount corresponding to the decrease in the flow rate, the total heat exchange The amount of decrease is relatively small. Since the temperature on the high pressure side of the high / low pressure heat exchanger 4 can be lowered until it approaches the refrigerant temperature on the low pressure side, the outlet temperature on the high pressure side of the high / low pressure heat exchanger 4 is higher than the refrigerant temperature on the low pressure side inlet. In this case, even if the flow rate of the refrigerant flowing through the bypass circuit 8 decreases, the outlet temperature on the high pressure side of the high / low pressure heat exchanger 4 decreases, and the amount of decrease in the heat exchange amount becomes relatively small. In this case, an increase in the flow rate of the refrigerant flowing through the ejector 3 increases the pressure Ps of the refrigerant discharged from the ejector 3, thereby reducing the pressure difference in the compressor 1 and reducing the compression work. Therefore, the operating efficiency of the apparatus is in a state where the operating efficiency does not change greatly even if the flow rate of the refrigerant flowing through the bypass circuit 8 is reduced, that is, the opening ratio is increased.

  On the other hand, when the outlet temperature on the high pressure side of the high / low pressure heat exchanger 4 decreases and is close to the refrigerant temperature on the low pressure side inlet, if the refrigerant flow rate flowing through the bypass circuit 8 decreases, the enthalpy difference on the high pressure side increases. Since it becomes impossible, the fall of a refrigerant | coolant flow volume will lead to the fall of the heat exchange amount in the high-low pressure heat exchanger 4 as it is. In this case, the effect of reducing the heating amount of the refrigerant flowing out of the ejector 3 is larger than the effect of increasing the suction pressure Ps of the compressor 1, and the operation efficiency is lowered. Therefore, when the opening ratio is increased, the operation efficiency is lowered.

Further, even if the opening ratio becomes small and the flow rate of the bypass circuit 8 increases, the heat exchange amount of the high / low pressure heat exchanger 4 does not increase inexhaustively but is defined by the refrigerant at the low pressure side outlet. When the refrigerant flow rate is constant, the refrigerant temperature at the low-pressure side outlet also increases as the heat exchange amount of the high-low pressure heat exchanger 4 increases. However, the rise in the refrigerant temperature at the low-pressure side outlet is regulated by the high-pressure side inlet temperature of the high-low pressure heat exchanger 4. That is, the high pressure side inlet temperature cannot be reached. Accordingly, when the opening ratio is decreased when the low pressure side outlet temperature of the high / low pressure heat exchanger 4 is close to the high pressure side inlet temperature, the heat exchange amount of the high / low pressure heat exchanger 4 is not increased. Thus, since the action of raising the suction pressure Ps of the compressor 1 due to the suction effect of the ejector 3 is reduced, the operation efficiency is lowered.
Conversely, when the low-pressure side outlet temperature and the high-pressure side inlet temperature of the high / low pressure heat exchanger 4 are not close, the opening ratio is reduced and the suction pressure Ps of the compressor 1 due to the suction effect of the ejector 3 is increased. Even if the action is reduced, the heat exchange amount of the high / low pressure heat exchanger 4 is increased, and more heat can be absorbed from the outside air. Even if the opening ratio is reduced, the operating efficiency does not change greatly.

In accordance with the above characteristics, the opening ratio between the ejector 3 and the expansion valve 5 is controlled based on the temperature difference between the inlet and outlet of the high / low pressure heat exchanger 4 so as to realize a high efficiency operation. First, according to the heat exchange characteristics of the high-low pressure heat exchanger 4, the temperature proximity between the high-pressure side inlet and the low-pressure side outlet and the temperature difference between the high-pressure side outlet and the low-pressure side inlet are determined. A judgment value is provided. Next, the high pressure side inlet temperature of the high / low pressure heat exchanger 4 is detected by the temperature sensor 10c, and the low pressure side outlet temperature is detected by the temperature sensor 10a, and a temperature difference between the detected temperatures is obtained. Similarly, the high-pressure side outlet temperature of the high-low pressure heat exchanger 4 is detected by the temperature sensor 10d and the low-pressure side inlet temperature is detected by the temperature sensor 10f, and the temperature difference between the detected temperatures is obtained (step S409).
Then, the temperature difference between the high-pressure side inlet and the low-pressure side outlet is compared with the determination value. If the temperature difference between the high-pressure side inlet and the low-pressure side outlet is smaller than the determination value (Yes in step S410), the measurement control device 11 It is determined that the opening ratio becomes too small and the heat exchange amount of the high-low pressure heat exchanger 4 is decreased due to the low-pressure temperature condition, and the opening ratio is controlled to be large (step S411). If the temperature difference between the high-pressure side outlet and the low-pressure side inlet is smaller than the determination value (Yes in step S412), the measurement control device 11 has an excessively large opening ratio, and the high-low pressure heat exchanger changes depending on the high-pressure side temperature condition. 4 is determined to be decreasing, and the opening ratio is controlled to be small (step S413).

  In this embodiment, when both temperature differences at the inlet and outlet of the high-low pressure heat exchanger 4 are larger than the determination value (No in step S410 and No in S412), the opening ratio is not changed. However, the opening ratio may be controlled so as to eliminate the situation on the closer side. That is, when the deviation between the temperature difference between the inlet and outlet and the judgment value is compared, and the deviation between the temperature difference between the high-pressure side inlet and the low-pressure side outlet and the judgment value is smaller, the opening ratio is controlled to be large, When the difference between the temperature difference between the high-pressure side outlet and the low-pressure side inlet and the determination value is smaller, the opening ratio is controlled to be small. Moreover, when each temperature difference of the entrance / exit of the high-low pressure heat exchanger 4 is smaller than a judgment value, it is good also as a driving | operation which does not change an opening ratio, but similarly to the case where each temperature difference is larger than a judgment value, The opening ratio may be controlled so as to eliminate the situation on the closer side. That is, the temperature difference between each inlet / outlet and the judgment value is compared, and if the temperature difference between the high-pressure side inlet and the low-pressure side outlet is closer and the deviation from the judgment value is larger, the difference is opened. The degree ratio is controlled to be large, and when the temperature difference between the high-pressure side outlet and the low-pressure side inlet is closer and the deviation from the judgment value is larger, the opening ratio is controlled to be small.

  When the refrigerant state at the high-pressure side outlet of the high-low pressure heat exchanger 4 is a gas-liquid two-phase state, that is, the discharge pressure of the compressor 1, which is the pressure of the high-low pressure heat exchanger 4, is detected by the pressure sensor 9b. When the saturation temperature obtained by converting the pressure and the high-pressure side outlet temperature detected by the temperature sensor 10d are substantially equal, the measurement control device 11 determines that the opening ratio is small, and the opening degree The ratio is greatly controlled. When the high-pressure side outlet is in a gas-liquid two-phase state, the gas refrigerant contained therein is a refrigerant that does not particularly function when flowing through the bypass circuit. That is, since the high pressure side of the high / low pressure heat exchanger 4 is not condensed and liquefied, the heat exchange amount hardly contributes. Also, when flowing into the evaporator, heat exchange by evaporative gasification is not carried out, so that it hardly contributes as a heat exchange amount. Therefore, the gas refrigerant present at the high-pressure side outlet of the high-low pressure heat exchanger 4 is a refrigerant that does not realize the purpose of the bypass circuit 8 that absorbs heat from the outside air. On the other hand, when the amount of the gas refrigerant flows into the ejector 3, the amount of pressure increase by the ejector 3 increases, so that the suction pressure Ps of the compressor 1 increases, the compression power decreases, and the operation efficiency increases. Therefore, the measurement control device 11 controls the opening ratio largely so as to avoid the waste of the gas refrigerant flowing to the high pressure side outlet of the high / low pressure heat exchanger 4 and reduces the flow rate of the refrigerant flowing to the high / low pressure heat exchanger 4. Let As a result, the refrigerant condensation on the high-pressure side is promoted, and the operation is brought into a supercooling state in which no gas refrigerant is mixed into the outlet, thereby realizing a highly efficient operation.

  In the rotation speed control of the compressor 1 and the opening control of the ejector 3 and the expansion valve 5, the control amount is determined by a PID control method based on a deviation from the target value.

  Next, the effect obtained by the configuration and control of this refrigeration air conditioner will be described. First, the gas refrigerant flowing out of the ejector 3 having a higher temperature than the outside air can be heated by the heat obtained from the outside air via the bypass circuit 8 and the high / low pressure heat exchanger 4. Therefore, the refrigeration cycle functions as a heat pump even in operating conditions where the radiator outlet becomes gas in the operation of heating the load medium that is near the saturation temperature with respect to the design pressure of the device or higher than that. It is possible to realize high-efficiency operation.

Further, the ejector 3 can increase the pressure of the refrigerant that is depressurized to a pressure Pe lower than the saturation pressure with respect to the outside air temperature by the bypass circuit 8 to the saturation pressure or more with respect to the outside air temperature. Therefore, compared with the case where the pressure of the refrigerant in the bypass circuit 8 is increased by the compressor 1 from the state of the pressure Pe, the compression power of the compressor 1 can be reduced, and a highly efficient operation can be realized.
Further, the operation compression ratio of the compressor 1 is reduced by the pressurizing action of the ejector 3, so that the increase range of the discharge temperature with respect to the suction temperature in the compressor 1 is reduced. Therefore, it is possible to operate at a higher intake temperature when the control is performed so as to reach the upper limit discharge temperature as described above. Since the heating amount of the refrigerant flowing out of the ejector 3 also increases in proportion to the temperature difference of the refrigerant, the higher the intake temperature of the compressor 1, the more heating amount can be obtained. Therefore, it can be operated as a heat pump with an increased amount of heat absorption, and a more efficient operation can be realized.

  Further, since the refrigerant flowing into the ejector 3 is in a gas state and the sucked refrigerant is also in a gas state, no liquid refrigerant is generated during the decompression and pressure increase processes of the ejector 3, and the refrigerant discharged from the ejector 3 is also a gas refrigerant. Become. Therefore, compared to the case where the ejector 3 is in a gas-liquid two-phase state, the efficiency in the liquid phase is not reduced and the ejector 3 can be used more efficiently than the case where the ejector 3 is in a gas-liquid two-phase state. Efficiency improvement effect is obtained.

  The accumulator 7 performs gas-liquid separation, so that the liquid phase refrigerant can be prevented from being mixed into the refrigerant sucked by the ejector 3. Even if there is a transient fluctuation and the refrigerant at the outlet of the evaporator 6 is in a gas-liquid two-phase state, the refrigerant sucked into the ejector 3 by the gas-liquid separation action can always be in a gas state, so that the liquid phase is mixed in. It is possible to suppress a decrease in efficiency due to the above, and a more efficient operation is possible.

  Even if the accumulator 7 is not arranged, the same function can be implemented by controlling the opening degree of the expansion valve 5. That is, by controlling the opening degree of the expansion valve 5, the refrigerant state at the outlet of the evaporator 6 is controlled to become superheated gas. Specifically, the target value of the refrigerant superheat degree at the outlet of the evaporator 6 is determined, and the measurement control device 11 controls the expansion valve 5 so that the superheat degree obtained from the temperature difference of the refrigerant temperature at the inlet and outlet of the evaporator 6 becomes the target value. Control the opening. By performing such control, the refrigerant sucked into the ejector 3 can always be in a gas state, and a reduction in efficiency due to mixing of the liquid phase can be suppressed, so that a more efficient operation can be performed.

  In addition, by controlling the opening of the ejector 3 and the expansion valve 5 so that the discharge temperature at the outlet of the compressor 1 is the maximum operable temperature, the refrigerant temperature difference in the radiator 2 can be maximized, and the heating capacity can be increased. It can be maximized and at the same time the operating efficiency of the device can be increased.

  In addition, the amount of heat exchange in the high / low pressure heat exchanger 4 is achieved by performing an operation to appropriately secure the refrigerant temperature difference between the high / low pressure inlet / outlet of the high / low pressure heat exchanger 4 by controlling the opening of the ejector 3 and the expansion valve 5 Can be suppressed. Therefore, it is possible to secure the amount of heating to the refrigerant that has exited the ejector 3, and it is possible to implement a more efficient operation by appropriately realizing the function as a heat pump.

  In addition, in this Embodiment, the structure which heats the hot water of a load side medium was shown, However, The structure which heats a load side medium is not restricted to this, It is applicable also in other cases. For example, a plate fin heat exchanger that heats air may be applied as the radiator 2 and may be applied to an apparatus that obtains high-temperature air for drying purposes. Moreover, it is good also as a separator type apparatus structure which connects the heat radiator 2 which heats a load medium by extension piping, and isolate | separates and arrange | positions from the part containing the compressor 1 other than the heat radiator 2. FIG.

  In the ejector 3, the needle portion 42 is driven (moved) in the axial direction by the electromagnetic coil portion 41 so that the flow passage area of the nozzle throat portion 43 c can be varied, but the nozzle of the ejector 3 is a fixed opening nozzle. The flow rate adjusting valve may be separately provided. For example, a second electronic expansion valve having a variable opening degree is arranged on the suction side, the downstream side, or in parallel of the ejector 3, and the opening degree control of the ejector 3 is performed by controlling the opening degree of the second electronic expansion valve. It is good also as a structure which substitutes.

  Further, in the opening control of the ejector 3 and the expansion valve 5, the total opening and the opening ratio are controlled so as to obtain a target state. You may implement the method of controlling. For example, control is performed so that the discharge temperature of the compressor 1 becomes a target value by opening degree control of the ejector 3, and control is performed so as to secure the inlet / outlet temperature difference of the high / low pressure heat exchanger 4 by opening degree control of the expansion valve 5. May be performed.

  In this embodiment, the expansion valve 5 is used as the pressure reducing device, but a second ejector may be used instead of the expansion valve 5. Since the second ejector is configured to suck and pressurize the refrigerant exiting the evaporator 6, the suction pressure of the ejector 3 increases, thereby increasing the suction pressure of the compressor 1 and reducing the compression power. More efficient operation can be performed.

In the present embodiment, the operation method for heating the high-temperature load-side medium has been described. However, the present embodiment can also be applied to heating the low-temperature load-side medium. In this case, the heat is exchanged while the refrigerant is condensed and liquefied in the radiator 2, and heat is applied to the load-side medium. Therefore, the opening degree of the ejector 3 is set to a fully closed state or a small opening degree near the fully closed state, and the refrigerant is mainly the compressor 1, the radiator 2, the high pressure side of the high / low pressure heat exchanger 4, the expansion valve 5, The evaporator 6, the accumulator 7, the ejector 3, the low pressure side of the high / low pressure heat exchanger 4, and the compressor 1 are flowed in this order. In this case, the refrigerant is liquefied by the radiator 2, and the evaporator 6 is operated to absorb the high-pressure liquid refrigerant after depressurizing the low-pressure two-phase refrigerant from outside air and heat it, and the operation of the refrigeration cycle is the same as that of a normal heat pump. . Therefore, in this case, a high-efficiency operation can be realized without the pressure increasing action by the ejector 3.
By controlling the opening degree of the ejector 3 and the expansion valve 5, a suitable refrigeration cycle can be operated according to the temperature of the load-side medium, so that a highly efficient device that can cope with various operating conditions can be obtained.

  Moreover, although the refrigerant | coolant applied in this Embodiment was R410A, other refrigerant | coolants are applicable similarly. A refrigerant such as CO 2 that operates in a supercritical state where the compressor 1 discharge pressure Pd is also applicable. In the case of a CO2 refrigerant, if the high pressure operates in a supercritical state, the refrigerant does not condense, but when cooled to a moderate low temperature in the radiator 2, it becomes a two-phase refrigerant after depressurization, and like the R410A refrigerant, Operation that absorbs heat from outside air while evaporating and gasifying is possible. However, the design pressure also exists in the apparatus using CO2, and when the load side medium having a temperature higher than the temperature determined for the design pressure is heated, the refrigerant at the outlet of the radiator 2 becomes high temperature, and the refrigerant is decompressed. However, there is a condition that the heat pump cannot perform the action of absorbing heat from the outside air while evaporating and gasifying. For example, when the design pressure is 13 MPa and the high pressure is 13 MPa, the radiator 2 outlet temperature is 74 ° C. or higher, that is, when the load-side medium of about 70 ° C. or higher is heated, the radiator 2 outlet Even if the refrigerant is depressurized, it becomes a gas state instead of a two-phase state, and heat cannot be absorbed from the outside air. Even under such conditions, by applying the configuration of the present embodiment, it is possible to function as a heat pump, and a more efficient operation can be performed.

Embodiment 2. FIG.
A second embodiment of the present invention is shown in FIG. FIG. 5 is a circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 2 of the present invention. In the figure, the same reference numerals are given to the same parts as those in FIG.
In FIG. 5, a gas-liquid separator 12 is provided at a branch portion of the ejector 3 and the bypass circuit 8 at the outlet of the radiator 2. The gas-liquid separator 12 is of a type that separates the liquid by gravity. The refrigerant flowing out from below the gas-liquid separator 12 flows to the bypass circuit 8, and the gas refrigerant flowing out from above the gas-liquid separator 12 flows to the ejector 3. Flowing.

  Next, the driving operation will be described. First, the radiator 2 outlet is operated in a gas state. In this case, since the gas refrigerant is distributed as it is to the ejector 3 and the bypass circuit 8 as in the first embodiment, the same as in the first embodiment. It becomes the operation.

  Next, a case where the outlet of the radiator 2 is in a gas-liquid two-phase state will be described. In the radiator 2, when the temperature of the inlet water of the load-side medium is high, heat exchange is performed so that the refrigerant state at the outlet of the radiator 2 becomes gas, but when the temperature of the water is appropriately reduced, the radiator 2 In some cases, the refrigerant is partially condensed and the refrigerant state at the outlet of the radiator 2 becomes a gas-liquid two-phase state. At this time, if the configuration is the same as that of the first embodiment, a part of the liquid refrigerant that has exited the radiator 2 flows into the ejector 3 as it is. When liquid refrigerant is mixed into the ejector 3, the refrigerant state in the ejector 3 becomes a gas-liquid two-phase state, so that the power recovery efficiency of the ejector is reduced. Further, since the power recovery amount obtained even if the liquid refrigerant itself is expanded is small, the influence of the reduction in power recovery efficiency is great, and the operation efficiency of the apparatus is reduced.

  Therefore, in the present embodiment, a gas-liquid separator is disposed at the outlet of the radiator 2 so that the liquid refrigerant is not mixed into the ejector 3 even if the refrigerant state at the outlet of the radiator 2 is a gas-liquid two-phase state. Thereby, the fall of the motive power collection | recovery efficiency of the ejector 3 by liquid refrigerant mixing can be avoided, and the operating efficiency of an apparatus rises. Further, since the liquid refrigerant acts to obtain heat absorption from the outside air by evaporating in the evaporator 6, the amount of heat absorption from the outside air can be increased by allowing more liquid refrigerant to flow into the bypass circuit 8, and the ejector 3 The amount of heating of the refrigerant flowing out can be increased. Thereby, the operating efficiency when the apparatus operates as a heat pump can be increased.

  In the gas-liquid separator 12, the gas / liquid is not completely separated and the gas flows to the ejector 3, and the liquid flows to the high / low pressure heat exchanger 4, but a part of the gas flows to the high / low pressure heat exchanger 4 as it is. Like that. This refrigerant distribution state is realized by opening control of the ejector 3 and the expansion valve 5. That is, as described above, when the operation is performed in a state in which the gas and liquid are completely separated and only the liquid refrigerant flows through the bypass, there is no refrigerant that condenses and liquefies in the high pressure portion of the high and low pressure heat exchanger 4. The refrigerant cools and the temperature decreases. At this time, with respect to the required amount of heat on the low pressure side in the high and low pressure heat exchanger 4, the cooling of the high pressure liquid refrigerant becomes larger by the amount that is not condensed, and the high pressure side outlet temperature of the high and low pressure heat exchanger 4 is low. The operation is close to the inlet temperature. In this state, when the opening degree control of the ejector 3 and the expansion valve 5 shown in the first embodiment is performed, the measurement control device 11 causes the opening / closing ratio to become too large, and the high / low pressure heat exchanger depends on the high temperature side temperature condition. 4 is determined to be low, and the opening ratio is controlled to be small so that the flow rate of the refrigerant flowing through the bypass circuit 8 increases. Since all of the liquid refrigerant at the outlet of the radiator 2 flows to the bypass flow path 8 before the control, when a refrigerant flow rate is additionally increased, part of the gas refrigerant flowing to the ejector 3 flows to the bypass circuit 8. Thus, the gas-liquid separation state as described above is obtained.

  In addition, about operation control, control similar to Embodiment 1 is implemented including said control. The operation at the time of control is the same as that in the first embodiment, and the same effect can be obtained.

Embodiment 3 FIG.
A third embodiment of the present invention is shown in FIG. FIG. 6 is a circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 3 of the present invention. In the figure, the same reference numerals are given to the same parts as those in FIG.
In FIG. 6, a gas-liquid separator 12 is provided at a branch portion between the ejector 3 and the bypass circuit 8 at the high-pressure side outlet of the high-low pressure heat exchanger 4. The gas-liquid separator 12 is a type that separates the liquid by gravity. The refrigerant flowing out from below the gas-liquid separator 12 flows to the bypass circuit 8, and the refrigerant flowing out from above the gas-liquid separator 12 flows to the ejector 3. .

  Next, the driving operation will be described. In the case of the same operating conditions as in the first embodiment, in the first embodiment, about 70% of the gas refrigerant at the outlet of the radiator 2 is caused to flow into the ejector 3, and the high-pressure side outlet of the high-low pressure heat exchanger 4 is in a supercooled state. However, since the branching of the gas refrigerant at the outlet of the radiator 2 to the ejector is not in the third embodiment and all flows to the high / low pressure heat exchanger 4, the high / low pressure heat exchanger 4 has a high pressure side outlet. The refrigerant state is a gas-liquid two-phase state. Therefore, in the present embodiment, a gas-liquid separator is disposed at the high pressure side outlet of the high / low pressure heat exchanger 4, and when the refrigerant at the high pressure side outlet of the high / low pressure heat exchanger 4 is branched to the ejector 3, Inflow of liquid refrigerant. Thereby, the fall of the motive power collection | recovery efficiency of the ejector 3 by liquid refrigerant mixing can be avoided, and the operating efficiency of an apparatus rises. Further, since the liquid refrigerant acts to obtain heat absorption from the outside air by evaporating in the evaporator 6, the amount of heat absorption from the outside air can be increased by allowing more liquid refrigerant to flow into the bypass circuit 8, and the ejector 3 The amount of heating of the refrigerant flowing out can be increased. Thereby, the operating efficiency when the apparatus operates as a heat pump can be increased.

  In addition, about operation control, control similar to Embodiment 1 is implemented including said control. The operation at the time of control is the same as that in the first embodiment, and the same effect can be obtained.

Embodiment 4 FIG.
A fourth embodiment of the present invention is shown in FIG. FIG. 7 is a circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 4 of the present invention. In the figure, the same reference numerals are given to the same parts as those in FIG.
In FIG. 7, the expander 13 is provided between the radiator 2 outlet and the high-low pressure heat exchanger 4 low-pressure side inlet. The expander 13 includes an expansion unit 13a and a compression unit 13b, and drives the compression unit 13b with expansion power recovered by the expansion unit 13a. In the expansion part 13a, a part of the refrigerant at the outlet of the radiator 2 flows in, expands and depressurizes, generates power, and flows out of the expansion part 13a. In the compression unit 13b, the saturated gas refrigerant that has exited the accumulator 7 flows in, and after compression and pressure increase, flows out of the compression unit 13b. The refrigerant that has flowed out of the expansion portion 13a and the refrigerant that has flowed out of the compression portion 13b merge, and then flow into the low-pressure side of the high-low pressure heat exchanger 4.

  The operation in the present embodiment is the same as that in the first embodiment, and the operation state of the refrigeration cycle is the same as that shown in FIG. Therefore, the gas refrigerant flowing into the high / low pressure heat exchanger 4 having a higher temperature than the outside air can be heated by the heat obtained from the outside air via the bypass circuit 8 and the high / low pressure heat exchanger 4. For this reason, in the operation of heating the high-temperature load medium, the refrigeration cycle can be made to function as a heat pump even under operating conditions in which the radiator outlet becomes gas, and a highly efficient operation can be realized.

Further, the expander 13 can raise the pressure of the refrigerant, which is decompressed to a pressure Pe lower than the saturation pressure with respect to the outside air temperature, by the bypass circuit 8 to be higher than the saturation pressure with respect to the outside air temperature. Therefore, compared with the case where the pressure of the refrigerant in the bypass circuit 8 is increased by the compressor 1 from the state of the pressure Pe, the compression power of the compressor 1 can be reduced, and a highly efficient operation can be realized.
In general, since the power recovery efficiency of the expander 13 is higher than that of the ejector, the boosting width is larger than that in the case where the ejector is applied, and a more efficient operation can be performed.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Radiator, 3 Ejector, 3a Suction part inlet, 4 High-low pressure heat exchanger, 5 Expansion valve, 6 Evaporator, 7 Accumulator, 8 Bypass circuit, 9a, 9b Pressure sensor, 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10i Temperature sensor, 11 Measurement control device, 12 Gas-liquid separator, 13 Expander, 13a Expansion unit, 13b Compression unit, 41 Electromagnetic coil unit, 42 Needle unit, 43 Nozzle unit, 43a Depressurization part, 43b Wide end part, 43c Nozzle throat part, 44 Mixing part, 45 Diffuser part.

Claims (1)

A refrigeration cycle in which a first compressor, a radiator, an expansion section, and a high-low pressure heat exchanger low-pressure section are sequentially connected in an annular shape;
A bypass circuit that branches between the radiator and the expansion section, and merges between the expansion section and the high-low pressure heat exchanger low-pressure section;
On this bypass circuit, a high-low pressure heat exchanger for exchanging heat with the refrigerant flowing in the high-low pressure heat exchanger low-pressure section, a high-pressure section, a decompression device, an evaporator, and a second compressor driven by the expansion section One after another
When the heat radiator heats a load medium having a temperature higher than a predetermined temperature, the gas refrigerant from the compressor is cooled and output in a gas state, and the expansion unit inputs the refrigerant from the heat radiator in a gas state. And the said 2nd compressor inputs the refrigerant | coolant from the said evaporator in a gas state, The refrigeration air conditioner characterized by the above-mentioned.

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