JP4082435B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus using an ejector in a refrigeration cycle.

A compressor, a condenser, a first expansion device, an ejector, a first evaporator, and a gas-liquid separator are sequentially connected by piping, a second evaporator is connected to the ejector suction section, and the gas-liquid separator and the second A refrigeration apparatus having a second expansion device between evaporators has been proposed (for example, Japanese Patent Laid-Open No. 52-30951).
In this method, since the pressure at the suction of the compressor can be made higher than the evaporation pressure of the second evaporator, the refrigerant gas density at the suction of the compressor does not decrease. For this reason, the compression ratio does not increase, and high-efficiency operation is possible.
JP 52-30951 A

However, the above-described refrigeration apparatus using an ejector has many problems in terms of load fluctuation, refrigerant flow rate relative to startup, and refrigerant amount control.
In addition, there are many problems such that the performance of the ejector is not stable with respect to the load fluctuation, and the performance cannot be ensured for the operation at the time of starting, stopping and unsteady.

The present invention has been made to solve such problems, and an object of the present invention is to perform appropriate refrigerant amount control by providing a gas-liquid separator with means for detecting a liquid level.
Moreover, it aims at performing appropriate refrigerant | coolant flow control based on the refrigerant | coolant superheat degree by the side of an evaporator outlet.
It is another object of the present invention to provide a refrigeration apparatus that ensures reliability without causing a liquid refrigerant to flow backward upon restart.
Furthermore, it aims at ensuring the performance and reliability of the freezing apparatus which has an ejector.

Refrigeration apparatus according to the present invention comprises a liquid level detection means provided in the gas-liquid separator, bypassing the first evaporator, a bypass circuit having an on-off valve or flow control valve, the liquid level detection means said And a control means for opening the on-off valve or the flow rate regulating valve of the bypass circuit until the refrigerant amount reaches a predetermined amount when the refrigerant amount shortage of the gas-liquid separator is detected.

  Further, a liquid level detection means provided in the gas-liquid separator, a second flow rate control valve connected between the gas-liquid separator and the second evaporator on the outlet side of the gas-liquid separator, The first flow rate adjustment valve, the second bypass circuit that bypasses the ejector, the third flow rate adjustment valve provided in the second bypass circuit, and the liquid level detection means have detected an insufficient refrigerant amount in the gas-liquid separator. Control means for closing the first flow rate valve and the second flow rate valve and adjusting the valve opening of the third flow rate control valve until the refrigerant amount reaches a predetermined amount. is there.

  The nozzle unit has a nozzle unit, a diffuser unit, and a suction unit. The high pressure refrigerant is reduced by the nozzle unit and mixed with a refrigerant gas flowing from the evaporator through the suction unit. A gas-liquid separator for separating the refrigerant flowing out from the ejector into refrigerant gas and refrigerant liquid, supplying the refrigerant liquid to the evaporator, and supplying the refrigerant gas to the compressor, and the gas-liquid separator A flow control valve provided between the separator and the evaporator, and the gas-liquid separator is installed at a position higher than the evaporator and the refrigerant of the gas-liquid separator when the refrigeration apparatus is stopped The liquid flows into the evaporator.

  The nozzle unit has a nozzle unit, a diffuser unit, and a suction unit. The nozzle unit depressurizes the high-pressure refrigerant and mixes it with a refrigerant gas flowing from the evaporator through the suction unit. A gas-liquid separator for separating the refrigerant flowing out of the ejector into refrigerant gas and refrigerant liquid, supplying the refrigerant liquid to the evaporator, and supplying the refrigerant gas to the compressor, and the gas-liquid separator A flow control valve provided between the separator and the evaporator, and a bypass circuit bypassing the other flow control valve and the other evaporator provided between the condenser and the gas-liquid separator, The ejector is provided in the bypass circuit.

  In addition, a compressor, a condenser, an on-off valve, a first flow rate adjustment valve, a first evaporator, and a gas-liquid separator are sequentially connected by piping, and an ejector is connected to a circuit that bypasses the first flow rate adjustment valve and the first evaporator. A pressure regulating valve between the junction of the bypass circuit and the outlet of the first evaporator to a pipe connecting the first evaporator and the gas-liquid separator, and suctioning the gas-liquid separator and the ejector In a refrigeration apparatus comprising a second flow rate control valve connected to a pipe via a second evaporator and further connected to a pipe between the gas-liquid separator and the second evaporator. Control means for detecting the condensation pressure or the condensation temperature of the condenser and controlling the condensation state of the condenser so as to reach the target condensation pressure or the target condensation temperature, and a pressure detection means and a temperature detection means. The first evaporator outlet pressure and temperature A control means for adjusting the refrigerant flow rate with the first flow rate control valve and a pressure detection means or a temperature detection means so as to detect and achieve a target superheat degree, and the evaporation pressure or evaporation temperature of the second evaporator is controlled. Control means for detecting and adjusting the refrigerant flow rate of the second flow rate adjusting valve so as to achieve the target evaporation pressure or the target evaporation temperature is provided.

Refrigeration apparatus according to the present invention comprises a liquid level detection means provided in the gas-liquid separator, to bypass the first evaporator, a bypass circuit having an on-off valve or flow control valve, the liquid level detection means the gas When detecting that the amount of refrigerant in the liquid separator is insufficient, control means for opening the on-off valve or the flow rate control valve of the bypass circuit until the refrigerant amount reaches a predetermined amount is provided. A shortage of refrigerant in the liquid separator can be solved, and a refrigeration apparatus with high performance and reliability can be provided.

  Further, a liquid level detection means provided in the gas-liquid separator, a second flow rate control valve connected between the gas-liquid separator and the second evaporator on the outlet side of the gas-liquid separator, A second bypass circuit that bypasses the first flow rate control valve and the ejector, a third flow rate control valve that is provided in the second bypass circuit, and the liquid level detection means detect an insufficient refrigerant amount in the gas-liquid separator. A control means for closing the first flow rate valve and the second flow rate valve and adjusting the valve opening of the third flow rate control valve until the refrigerant amount reaches a predetermined amount. Therefore, it is possible to perform control corresponding to the liquid amount of the gas-liquid separator by adjusting and controlling the valve opening degree of the third flow rate control valve while cooling with the first evaporator.

  The nozzle unit has a nozzle unit, a diffuser unit, and a suction unit. The high pressure refrigerant is reduced by the nozzle unit and mixed with a refrigerant gas flowing from the evaporator through the suction unit. A gas-liquid separator for separating the refrigerant flowing out from the ejector into refrigerant gas and refrigerant liquid, supplying the refrigerant liquid to the evaporator, and supplying the refrigerant gas to the compressor, and the gas-liquid separator A flow control valve provided between the separator and the evaporator, and the gas-liquid separator is installed at a position higher than the evaporator, so that when the refrigeration apparatus stops, the gas-liquid separator Since the remaining refrigerant liquid can be made to flow into the evaporator, it is possible to provide a refrigeration apparatus that ensures reliability against restart.

  The nozzle unit has a nozzle unit, a diffuser unit, and a suction unit. The nozzle unit depressurizes the high-pressure refrigerant and mixes it with a refrigerant gas flowing from the evaporator through the suction unit. A gas-liquid separator for separating the refrigerant flowing out from the ejector into refrigerant gas and refrigerant liquid, supplying the refrigerant liquid to the evaporator, and supplying the refrigerant gas to the compressor, and the gas-liquid separator A flow control valve provided between the separator and the evaporator, and a bypass circuit bypassing the other flow control valve and the other evaporator provided between the condenser and the gas-liquid separator, Since the ejector is provided in the bypass circuit, the refrigerant state at the ejector inlet is constant, the ejector performance is stabilized, and the refrigeration capacity is constant in the evaporator and the other evaporators. It is possible to provide a that the refrigeration apparatus.

  In addition, a compressor, a condenser, an on-off valve, a first flow rate adjustment valve, a first evaporator, and a gas-liquid separator are sequentially connected to the bypass circuit to bypass the first flow rate adjustment valve and the first evaporator. A pressure regulating valve between a junction of the bypass circuit and a first evaporator outlet to a pipe connecting the first evaporator and the gas-liquid separator, the gas-liquid separator and the ejector In a refrigeration system comprising a second flow rate control valve connected to the suction part via a second evaporator and further connected between the gas-liquid separator and the second evaporator, pressure detecting means or temperature A detecting means for detecting the condensing pressure or condensing temperature of the condenser and controlling the condensing state of the condenser so as to reach a target condensing pressure or a target condensing temperature; a pressure detecting means; and a temperature detecting means. Means of the first evaporator outlet pressure And a control means for adjusting the refrigerant flow rate with the first flow rate control valve, a pressure detection means or a temperature detection means so as to achieve a target superheat degree, and an evaporation pressure of the second evaporator or Since the control means for detecting the evaporating temperature and adjusting the refrigerant flow rate of the second flow rate control valve so as to reach the target evaporating pressure or the target evaporating temperature is provided By fully closing the valve, it is possible to provide a refrigeration apparatus capable of normal refrigeration cycle operation only with the first evaporator.

Embodiment 1 FIG.
FIG. 1 shows an example of an embodiment of the present invention, where a compressor 1, a condenser 2, a first flow rate adjustment valve 3, an ejector 4, a first evaporator 5, a second flow rate adjustment valve 13, and a second evaporator 6 are shown. The gas-liquid separator 7 is sequentially connected by piping, and the gas-liquid separator 7 is a refrigeration apparatus provided with a liquid level sensor 8 as liquid level detection means for detecting the height of the liquid level. FIG. 2 is a structural diagram of the ejector. The ejector includes a nozzle portion 10 and a diffuser portion 11. FIG. 3 is a refrigeration cycle operating point of the embodiment on the pressure-enthalpy diagram. In the figure, an arrow 9 indicates the flow of the refrigerant.

  The refrigeration cycle operation will be described with reference to FIGS. 1, 2, and 3. The high-temperature and high-pressure refrigerant gas R1 discharged from the compressor 1 enters the condenser 2, where it is condensed into a high-pressure liquid refrigerant R2, and the refrigerant flow rate is adjusted by the first flow rate adjusting valve 3 and sent to the ejector 4. The refrigerant sent to the ejector 4 enters the state R3 at the nozzle part outlet E2 and flows into the mixing part of the diffuser part 11. After mixing with refrigerant gas in state R4 flowing from E4 in the mixing section, the refrigerant in state R5 recovers pressure from Pe2 to Pe1 by the diffuser 11, and becomes refrigerant in state R6. The refrigerant discharged from the ejector 4 flows into the first evaporator 5 and is sent to the gas-liquid separator 7 in a wet state R7. In the gas-liquid separator 7, the refrigerant gas in the state R8 is sucked into the compressor 1, while the refrigerant liquid in the state R9 is depressurized by the second flow control valve 13, sent to the second evaporator 6, and evaporated to the state R4. And flows to the suction part E4 of the ejector 4. For this reason, when there are two evaporators as in a normal refrigeration system and they are operating at different evaporation pressures Pe1, Pe2 (Pe1> Pe2), it is necessary to match the compressor suction pressure with the evaporation pressure Pe2. However, by using the ejector, the suction pressure of the compressor 1 is not reduced because the suction pressure of the compressor can be adjusted to the evaporation pressure Pe1. Therefore, the compression ratio can be reduced, and highly efficient operation is possible.

Next, the effectiveness of the R404A or R507 ejector as a refrigerant will be described. Here, only R404A will be described, but R507 may be used.
1, the refrigerant flow rate at the compressor 1 is Gs, the refrigerant flow rate at the second evaporator 6 is Ge, the ratio of the refrigerant flow rate Ge at the second evaporator 6 and the refrigerant flow rate Gs at the compressor 1 is the flow rate ratio α. (= Ge / Gs). In general, the relationship between the ejector efficiency η, the flow rate ratio α, and the enthalpy is expressed by equation (1).
α = {(H _R10 −H _R3 ) / (H _R11 −H _R4 )} η (1)
H is enthalpy and the subscript corresponds to the refrigeration cycle operating point of FIG. R2 → R3, R4 → R11 is an isentropic change, and R2 → R10 is an isenthalpy change. As can be seen from the equation (1), the smaller the ratio H _R11 → H _{R4 and the} larger the ratio H _R10 → H _R3 , the larger the flow rate ratio α in the case of the same ejector efficiency. As a result, the refrigerant flow rate in the second evaporator 6 increases, and the refrigeration capacity of the second evaporator 6 can be increased. (H _R10 −H _R3 ) / (H _R11 −H _R4 ) is a value determined by the physical properties of the refrigerant. For example, (H _R10 −H _R3 ) / (H _R11 −H _R4 ) of R22 and R404A when the difference between the evaporation pressure Pe1 in the first evaporator 5 and the evaporation pressure Pe2 in the second evaporator 6 is constant 50 kPa. FIG. 4 shows the relationship between the temperature and the evaporation temperature of the second evaporator 6. When comparing R22 and R404A in FIG. 4, (H _R10 −H _R3 ) / (H _R11 −H _R4 ) of R404A is about 1.7 times larger than that of R22. When the same ejector efficiency η is used, R404A has a larger flow rate ratio α than R22, and it is easy to increase the refrigeration capacity in the second evaporator 6. From the above, it can be said that the refrigeration apparatus using R404A as the refrigerant has a greater effect of the ejector 4 than the other refrigerants from the viewpoint of physical properties.
That is, the ejector can be effectively used by using a refrigerant having a large value of (H _R10 −H _R3 ) / (H _R11 −H _R4 ), for example, R404A and R507 which are larger than the refrigerant R22 conventionally used. Can do.

Next, a driving method will be described. For example, the first flow rate adjusting valve 3 and the second flow rate adjusting valve 13 employ the electronic expansion valve 3 and the electronic expansion valve 13, respectively, and the gas-liquid separator 7 includes the liquid level sensor 8, and the liquid level sensor When 8 detects that the liquid level at the gas-liquid separator 7 is not a predetermined amount, the first first flow rate control valve control means adjusts the flow rate of the refrigerant flowing through the electronic expansion valve 3 to Control the amount. Specifically, when the liquid level is lowered by the gas-liquid separator 7, the opening of the electronic expansion valve 3 is increased, and the amount of refrigerant is controlled so that the liquid level becomes higher.
On the contrary, when the liquid level is high, the opening degree of the electronic expansion valve 3 is reduced to control the liquid level to be lowered. As a result, the amount of refrigerant can be properly controlled.
Further, the refrigerant flow rate control of the second evaporator 6 uses, for example, a pressure sensor 18 as a pressure detection means for detecting pressure, and a temperature sensor 19 as a temperature detection means for detecting the temperature of the evaporator, for example. The first second flow rate adjusting valve control means controls the refrigerant flow rate by the electronic expansion valve 13 so that the pressure P and temperature T at the outlet of the second evaporator are detected and the degree of superheat at the outlet of the evaporator becomes constant. To do.
When the liquid refrigerant is not present or insufficient in the gas-liquid separator 7 such as at the time of start-up, the second second flow rate control valve control means fully closes the electronic expansion valve 13 by the detection of the liquid level sensor 8. Only the first evaporator 5 is operated. After the liquid level sensor 8 detects that the liquid level has reached the target value, the opening degree of the electronic expansion valve 13 is adjusted.
However, the first and second second flow rate control valve control means may be common control means.

Embodiment 2. FIG.
FIG. 5 shows a second embodiment of the invention. For example, a pressure sensor 20 is installed at the outlet of the first evaporator 5 of the first embodiment of the invention as first first evaporator pressure detection means for detecting the outlet pressure of the first evaporator. For example, a temperature sensor 21 is provided at the outlet of the evaporator 5 as first first evaporator temperature detecting means for detecting the outlet temperature of the first evaporator. In the normal operation mode, as in the first embodiment of the present invention, the liquid level of the gas-liquid separator 7 is detected, for example, the liquid level sensor 8 detects the liquid level, and the first first flow rate is detected. The control valve control means controls the amount of refrigerant in the gas-liquid separator 7 by adjusting the opening of the first flow rate control valve, for example, the electronic expansion valve 3.
When only the first evaporator 5 is operated, the second flow rate control valve 13, for example, the electronic expansion valve 13, is fully closed, and the pressure P at the outlet of the first evaporator 5 is detected by the pressure sensor 20, Further, the temperature T is detected by the temperature sensor 21, and the second first flow rate control valve control means controls the refrigerant flow rate by the electronic expansion valve 3 so that the degree of superheat at the evaporator outlet becomes constant.
However, the first and second first flow rate control valve control means may be common control means.

Embodiment 3 FIG.
FIG. 6 shows a third embodiment of the invention. The first evaporator 5 according to the second embodiment of the present invention includes, for example, a first solenoid valve 12 as a first on-off valve, a first bypass circuit 15 that bypasses the first evaporator 5, and a second on-off switch on the bypass circuit 15. A second electromagnetic valve 14 is provided as a valve.

In the normal operation mode, the electromagnetic valve 14 of the first bypass circuit 15 is closed and the electromagnetic valve 12 of the first evaporator 5 is opened. When the liquid level sensor 8 detects that there is no refrigerant in the gas-liquid separator 7 or a shortage is detected, the first on-off valve control means closes the solenoid valve 12 of the first evaporator 5 and the solenoid valve of the bypass circuit 15. 14 is opened so that the refrigerant can bypass the first evaporator 5, and the refrigerant flows through the bypass circuit 15 until the target liquid level is reached by the liquid level sensor 8. When the target liquid level is reached, the normal operation mode is set.
The refrigerant flow rate control of the second evaporator 6 is performed by using, for example, a pressure sensor 18 as a means for detecting pressure and a temperature sensor 19 as a means for detecting the temperature of the evaporator, for example. The outlet pressure P and temperature T are detected, and the first second flow rate control valve control means controls the electronic expansion valve 13 so that the degree of superheat at the evaporator outlet becomes constant.
By closing the solenoid valve 12 of the first evaporator 5 and opening the solenoid valve 14 of the bypass circuit 15, only the second evaporator 6 can be operated, for example, at the time of heater defrost. Similarly, when it is desired to perform heater defrosting with the first evaporator 5, when the first electromagnetic valve 12 of the first evaporator 5 is closed and the second electromagnetic valve 14 of the bypass circuit 15 is opened, the first evaporator By defrosting 5 and operating the second evaporator 6, it is possible to suppress an increase in the internal temperature. Conversely, when the electronic expansion valve 13 is fully closed and the second electromagnetic valve 14 of the bypass circuit 15 is closed, only the first evaporator 5 is operated, and only the second evaporator 6 can be in a defrost state.

Embodiment 4 FIG.
FIG. 7 shows a fourth embodiment of the invention. A compressor 1, a condenser 2, a first flow rate adjustment valve 3, an ejector 4, a third flow rate adjustment valve 17, a second bypass circuit 16, a first evaporator 5, a gas-liquid separator 7, which bypass the ejector 4, The second flow rate control valve 13, the second evaporator 6 and the like are sequentially connected by piping. Further, the gas-liquid separator 7 is a refrigeration apparatus provided with a liquid level sensor 8 as means for detecting the height of the liquid level, for example. Here, electronic expansion valves are used for the first flow rate adjustment valve 3, the second flow rate adjustment valve 13, and the third flow rate adjustment valve 17.
In the normal operation mode, the opening of the electronic expansion valve 17 is fully closed, the refrigerant flows through the ejector 4, the liquid level of the gas-liquid separator 7 is detected by the liquid level sensor 8, and the first first The flow rate control valve control means controls the refrigerant amount by the electronic expansion valve 3.
The refrigerant flow rate control of the second evaporator 6 is performed by using, for example, a pressure sensor 18 as a means for detecting pressure and a temperature sensor 19 as a means for detecting the temperature of the evaporator, for example. The outlet pressure P and temperature T are detected, and the first second flow rate control valve control means controls the electronic expansion valve 13 so that the degree of superheat at the evaporator outlet becomes constant.
At the time of start-up, the first third flow rate control valve control means fully closes the electronic expansion valve 3 and further closes the electronic expansion valve 13 so that the refrigerant does not flow to the ejector 4 and the second evaporator 6. To do. While detecting the liquid level height of the gas-liquid separator 7 by the liquid level sensor 8, the amount of refrigerant is controlled by adjusting the opening degree of the electronic expansion valve 17 of the circuit 16 that bypasses the ejector 4. Until the liquid level reaches the target value, the electronic expansion valve 13 is fully closed and only the first evaporator 5 is operated. After the liquid level reaches the target value, the normal operation mode is set.

Embodiment 5. FIG.
FIG. 8 shows a fifth embodiment of the invention. For example, the first evaporator 5 of the fourth embodiment has a first solenoid valve 12 as a first on-off valve, a first bypass circuit 15 to bypass the first evaporator 5, and a second on-off valve in the circuit. An electromagnetic valve 14 is provided.
In the normal operation mode, the second electromagnetic valve 14 of the bypass circuit 15 is closed, the first electromagnetic valve 12 of the first evaporator 5 is opened, the opening of the electronic expansion valve 17 is fully closed, and the refrigerant is supplied to the ejector 4. Make it flow. Detected by the liquid level sensor 8 of the gas-liquid separator 7, the first first flow rate control valve control means adjusts the opening of the electronic expansion valve 3, thereby controlling the refrigerant amount. The refrigerant flow rate control of the second evaporator 6 is performed by using, for example, a pressure sensor 18 as a means for detecting pressure and a temperature sensor 19 as a means for detecting the temperature of the evaporator, for example. The outlet pressure P and temperature T are detected, and the first second flow rate control valve control means controls the electronic expansion valve 13 so that the degree of superheat at the evaporator outlet becomes constant.
When the liquid level sensor 8 detects that there is no refrigerant in the gas-liquid separator 7 or a shortage is detected, the second third flow rate control valve control means closes the first electromagnetic valve 12 of the first evaporator 5, The second electromagnetic valve 14 of the bypass circuit 15 is opened, the refrigerant is bypassed in the first evaporator 5, the electronic expansion valve 3 is fully closed, and the electronic expansion valve 17 of the circuit 16 bypassing the ejector is used to The evaporator 5 is bypassed until the target liquid level is reached by the sensor 8, and when the target liquid level is reached, the normal operation mode is set.
However, the second third flow rate control valve control means may be the same control means as the first third flow rate control valve control means of the fourth embodiment.
By closing the solenoid valve 12 of the first evaporator 5 and opening the solenoid valve 14 of the bypass circuit 15, only the second evaporator 6 can be operated. Similarly, when a heater defrost or the like is used, when the solenoid valve 12 of the first evaporator 5 is closed and the solenoid valve 14 of the bypass circuit 15 is opened, the first evaporator 5 performs defrosting and the second evaporation. By operating the vessel 6, it is possible to suppress an increase in the internal temperature. Conversely, when the electronic expansion valve 13 is fully closed and the solenoid valve 14 of the bypass circuit 15 is closed, the first evaporator 5 can be in the operating state and the second evaporator 6 can be in the defrosted state.

Embodiment 6 FIG.
FIG. 9 shows a sixth embodiment of the invention. The compressor 1, the condenser 2, the first flow rate adjustment valve 3, the ejector 4, the first evaporator 5, the second flow rate adjustment valve 13, and the second evaporator 6 are sequentially connected by piping, and further, the gas-liquid separator 7. The refrigeration apparatus includes a liquid level sensor 8 as means for detecting the height of the liquid level. The first flow rate adjusting valve 3, the ejector 4 and the third evaporator 23 bypassing the first evaporator 5, and the bypass circuit 23 includes a fourth flow rate adjusting valve 24. Here, electronic expansion valves are used for the first flow rate adjustment valve 3, the second flow rate adjustment valve 13, and the fourth flow rate adjustment valve 24.
In the normal operation mode, the electronic expansion valve 24 is fully closed so that the refrigerant flows through the ejector 4. The liquid level sensor 8 detects the liquid level height installed in the gas-liquid separator 7, and the first first flow rate control valve control means controls the refrigerant amount by the electronic expansion valve 3.
The refrigerant flow rate control of the second evaporator 6 is performed by using, for example, a pressure sensor 18 as a means for detecting pressure and a temperature sensor 19 as a means for detecting the temperature of the evaporator, for example. The outlet pressure P and temperature T are detected, and the first second flow rate control valve control means controls the electronic expansion valve 13 so that the degree of superheat at the evaporator outlet becomes constant.
When the liquid does not exist in the gas-liquid separator or when the liquid is insufficient, the first fourth flow rate control valve control means fully closes the electronic expansion valve 3 so that the refrigerant does not flow to the ejector. The operation is performed while adjusting the opening of the electronic expansion valve 24 until the target liquid level is reached by flowing the refrigerant. After reaching the target liquid level in the gas-liquid separator 7, the normal operation mode is set.

Embodiment 7 FIG.
FIG. 10 shows an example of an embodiment of the present invention. The compressor 1, the condenser 2, the liquid reservoir 26, the third on-off valve 27, the ejector 4, the first evaporator 5, the gas-liquid separator 7, and the second flow rate. The control valve 13 and the second evaporator 6 are sequentially connected by piping. In the figure, an arrow 9 indicates the flow of the refrigerant.
The refrigeration cycle operation will be described with reference to FIGS. 2, 3, and 10. The high-temperature and high-pressure refrigerant gas R1 discharged from the compressor 1 enters the condenser 2, where it condenses to become a high-pressure liquid refrigerant R2, and is sent to the ejector 4. The refrigerant sent to the ejector 4 enters the state R3 at the nozzle part outlet E2 and flows into the mixing part of the diffuser 11. After mixing with refrigerant gas in state R4 flowing from E4 in the mixing section, the refrigerant in state R5 recovers pressure from Pe2 to Pe1 by the diffuser 11, and becomes refrigerant in state R6. The refrigerant that has exited the ejector 4 flows into the first evaporator 5, enters a wet state R 7, and is sent to the gas-liquid separator 7. In the gas-liquid separator 7, the refrigerant gas in the state R8 is sent to the suction side of the compressor 1, while the refrigerant liquid in the state R9 is depressurized by the second flow control valve 13, sent to the second evaporator 6, and evaporated. R4 flows to the suction part E4 of the ejector 5. For this reason, when there are two evaporators as in a normal refrigeration system and they are operating at different evaporation pressures Pe1, Pe2 (Pe1> Pe2), it is necessary to match the compressor suction pressure with the evaporation pressure Pe2. However, by using the ejector, the suction pressure of the compressor 1 is not reduced because the suction pressure of the compressor can be adjusted to the evaporation pressure Pe1. Therefore, the compression ratio can be reduced, and highly efficient operation is possible.

A driving method will be described. In the embodiment of the present invention, the second flow rate adjusting valve 13 is an electronic expansion valve 13, the third on-off valve 27 is an electromagnetic valve 27, and the first second evaporator pressure for detecting the pressure at the second evaporator outlet. A pressure sensor 18 is used as the detection means 18, and a temperature sensor 19 is used as the first second evaporator temperature detection means 19 that detects the temperature at the outlet of the second evaporator. During operation, the solenoid valve 27 is kept open, the pressure and temperature at the outlet of the second evaporator are measured by the pressure sensor 18 and the temperature sensor 19, and the first second flow rate control valve control means 6a is controlled by the second evaporator outlet. And the flow rate of the refrigerant sent to the second evaporator 6 is controlled by adjusting the opening degree of the electronic expansion valve 13 so as to reach a predetermined target superheat degree. At the time of stop, like the normal refrigeration apparatus, the electromagnetic valve 27 is fully closed and the refrigeration apparatus is stopped by the pump down operation.
In this way, when the refrigeration apparatus is stopped by the pump-down operation, the refrigerant liquid remains in the gas-liquid separator 7 the next time the refrigeration apparatus is started, and therefore, the refrigerant may return suddenly to the compressor 1. There is a problem of reliability. Therefore, when the gas-liquid separator 7 is placed above the second evaporator 6 and the refrigeration system is stopped, the electronic expansion valve 13 is fully opened, and the refrigerant liquid in the gas-liquid separator 7 is second evaporated. To flow into the vessel 6. By moving the refrigerant liquid to the second evaporator 6 in this way, it becomes difficult for the refrigerant liquid to return to the compressor 1 at the time of restart, thereby improving the reliability.
Further, at the time of restart, the electronic expansion valve 13 is fully closed by the first second flow rate control valve control means 6a, the degree of superheat is calculated by the pressure sensor 18 and the temperature sensor 19 at the outlet of the second evaporator, When the degree of superheat is reached, it is desirable to open the electronic expansion valve 13 and eliminate the liquid refrigerant in the second evaporator 6. Thereafter, the refrigerant flow rate in the second evaporator 6 is controlled by the electronic expansion valve 13 by the first second flow rate adjusting valve control means 6a so as to achieve a predetermined target superheat degree. By performing this control, it is possible to eliminate the refrigerant that flows backward from the second evaporator 6 to the gas-liquid separator 7 at the time of startup, and the reliability is improved.

Embodiment 8 FIG.
FIG. 11 shows an eighth embodiment of the present invention. The compressor 1, the condenser 2, the liquid reservoir 26, the third on-off valve 27, the ejector 4, the first evaporator 5, the second evaporator 6 and the like are connected by piping. For example, in the embodiment of the present invention, the condenser 2 includes a pressure sensor 29 as the condensation pressure detecting means 29 that detects the condensation pressure at an intermediate point of the condenser 2. Instead of the condensation pressure detection means, a temperature sensor may be used as the condensation temperature detection means for detecting the condensation temperature. At the outlet of the second evaporator, a pressure sensor 18 is used as the first pressure detection means 18 and a temperature sensor 19 is used as the first temperature detection means 19.
Next, the effectiveness of condensing pressure control (control for condensing condensing pressure) will be described. 11, the refrigerant flow rate at the compressor 1 is Gc, the refrigerant flow rate at the second evaporator 6 is Ge, the ratio of the refrigerant flow rate Ge at the second evaporator 6 and the refrigerant flow rate Gc at the compressor 1 is a flow rate ratio α. (= Ge / Gc). In general, the relationship between the ejector efficiency η, the flow rate ratio α, and the enthalpy is expressed by equation (2).
α = (H _R10 −H _R3 ) · η / (H _R11 −H _R4 ) (2)
H is enthalpy and the subscript corresponds to the refrigeration cycle operating point of FIG. R2 → R3, R4 → R11 is an isentropic change, and R2 → R10 is an isenthalpy change. As can be seen from the equation (2), the larger H _R10 → H _R3 , the larger the flow rate ratio becomes for the same ejector efficiency. As a result, the ejector can be used effectively. That is, when the condensing pressure decreases, enthalpy H _R3 increases and H _R10 -H _R3 also decreases as can be seen from FIG. As a result, the flow rate ratio α decreases from the equation (2). Increasing the condensing pressure increases the flow rate ratio α, but the compression ratio increases, so the compressor performance decreases. As a result, Gc decreases, and the refrigerating capacity of the second evaporator does not increase. That is, the condensation pressure has an appropriate range.

  Next, a driving method will be described. In the case of an air-cooled condenser, the air volume is adjusted by the condensation pressure control means 2a so that the condensation pressure is detected by the pressure sensor 29 and reaches the target condensation pressure. Specifically, when the condensation pressure is lower than the target pressure, the air volume is decreased. Conversely, when the condensation pressure exceeds the target pressure, the air volume is increased. In the case of a water-cooled condenser, adjust the amount of water. Specifically, when the condensation pressure is lower than the target pressure, the amount of water is decreased. Conversely, when the condensation pressure is higher than the target pressure, the amount of water is increased. With such a control method, the condensation pressure is set within a target range. Further, the pressure and temperature at the outlet of the second evaporator are measured by the pressure sensor 18 and the temperature sensor 19, the degree of superheat at the outlet of the second evaporator is calculated, and the first second flow rate is set so as to reach the target degree of superheat. The flow rate of the refrigerant sent to the second evaporator 6 is controlled by adjusting the opening degree of the electronic expansion valve 13 by the adjusting valve control means 6a.

Embodiment 9 FIG.
FIG. 12 shows Embodiment 9 of the invention. The second evaporator 6 is provided with a pressure sensor 31 as the second evaporation pressure detecting means 31 for detecting the evaporation pressure. A temperature sensor may be used as the second evaporation temperature detection means in the second evaporator 6 instead of the second evaporation pressure detection means 31. Although the condenser 2 is provided with a pressure sensor as the condensation pressure detection means 29, it may be a condensation temperature temperature detection means. The condensing pressure or condensing temperature of the condenser 2 is controlled by the condensing pressure control means 2a as in the control of the eighth embodiment of the present invention. The evaporation pressure of the second evaporator 6 is detected by the pressure sensor 31, and the second flow rate adjustment valve 13 is controlled by the third second flow rate adjustment valve control means 6b so as to reach the target evaporation pressure. Specifically, when the evaporation pressure is larger than the target evaporation pressure, for example, the opening degree of the electronic expansion valve 13 is reduced as the flow rate adjustment valve 13. Conversely, when the evaporation pressure is lower than the target evaporation pressure, the opening degree of the electronic expansion valve 13 is increased. By this operation, the condensation pressure is constant and the second evaporation pressure is constant. Further, since the first evaporation pressure is substantially determined by the state of the inlet of the ejector nozzle and the nozzle diameter, the first evaporation pressure is also substantially constant. As a result, H _R10 −H _R3 and H _R11 −H _{R4 in} equation (2) are also constant, the flow rate ratio α is also constant, and the refrigeration capacity of the second evaporator 6 is constant. Such a control method is particularly effective in a refrigerated warehouse where the load fluctuation is small.

Embodiment 10 FIG.
FIG. 13 shows a tenth embodiment of the invention. The compressor 1, the condenser 2, the liquid reservoir 26, the third on-off valve 27, the first flow rate adjusting valve 3, the first evaporator 5, and the gas-liquid separator 7 are sequentially connected to form a circuit, and the first flow rate The fourth bypass circuit 28 for bypassing the control valve 3 and the first evaporator 5 is provided with the ejector 4, and the circuit connecting the second flow rate control valve 13 and the second evaporator 6 is connected to the gas-liquid separator 7 and the It is connected to the suction part E4 of the ejector 4. An electronic expansion valve 13 is provided as a second flow rate adjustment valve 13 between the gas-liquid separator 7 and the second evaporator 6. As the first flow rate adjusting valve 3, for example, an electronic expansion valve 3 is used. The condenser 2 has a pressure sensor 29 and a condensation pressure control means 2a as the condensation pressure detection means for detecting the condensation pressure, and a pressure as the second first evaporator pressure detection means for detecting the evaporation pressure of the first evaporator 5. The sensor 32 and the third first flow rate control valve control means 5a, the pressure sensor 31 and the third second flow rate control valve control means 6b as the second second evaporator pressure means for detecting the evaporation pressure of the second evaporator. It has.
In normal operation, in the condenser 2, the air volume and the water volume are increased or decreased by the condensation pressure control means 2a so that the target condensation pressure is obtained. For the first evaporator 5, the electronic expansion valve 3 is controlled by the third first flow rate control valve control means 5 a so as to achieve the target first evaporation pressure. For the second evaporator 6, the target first evaporation pressure is controlled. The electronic expansion valve 13 is controlled by the third second flow rate control valve control means 6b so as to obtain the double evaporation pressure. In normal operation, the flow rate of the refrigerant flowing through the ejector 4 is substantially constant, and the state of the ejector inlet is also substantially constant, so that the refrigerating capacity in the second evaporator 6 is substantially constant. Moreover, the refrigerating capacity of the second evaporator 6 is also substantially constant.
For example, when the temperature in the cabinet in which the first evaporator 5 is installed is high (when the load is large), there is a possibility that the gas-liquid separator 7 may run out of liquid. However, since the ejector 4 is provided in the bypass circuit 28 and the first evaporator 5 is bypassed as in the embodiment of the present invention, the refrigerant liquid can always be fed into the gas-liquid separator 7. Refrigerant liquid can be stored in the vessel 7 and the reliability is improved.

Embodiment 11 FIG.
FIG. 14 shows Embodiment 11 of the invention. The outlet pressure of the ejector 4 and the compression between the junction of the first evaporator 6 and the pipe connecting the gas-liquid separator 7 of the fourth bypass circuit 28 of the tenth embodiment of the invention and the outlet of the first evaporator For example, an evaporation pressure adjusting valve 34 is provided as a pressure adjusting valve 34 for always equalizing the machine suction pressure. The refrigerant load in the first evaporator 5 is increased, and the pressure at the outlet of the ejector 4 is increased. As a result, a pressure difference at the ejector 4 cannot be sufficiently secured, and a phenomenon in which the performance cannot be exhibited sufficiently occurs. By installing the evaporation pressure control valve 34, the pressure at the outlet of the ejector 4 can be made substantially constant, and the performance of the ejector 4 can be made constant. At the outlet of the first evaporator, there are a third pressure detection means 35 for detecting the first evaporator outlet pressure, a pressure sensor 35, a temperature sensor 36 and a second temperature detection means 36 for detecting the first evaporator outlet temperature. 4 first flow rate control valve control means 5b.
The pressure control of the condenser 2 and the second evaporator 6 is the same as in the tenth embodiment.
In normal operation, the flow rate of the refrigerant flowing through the ejector 4 is substantially constant, and the state of the ejector inlet is also substantially constant, so that the refrigerating capacity in the second evaporator 6 is substantially constant. Further, the degree of superheat at the outlet of the first evaporator is obtained from the pressure sensor 35 and the temperature sensor 36 at the outlet of the first evaporator, and the opening degree of the electronic expansion valve 3 is adjusted so as to achieve the target degree of superheat. By using the refrigerant circuit as in the embodiment of the present invention, the refrigerating capacity of the first evaporator 5 can be made variable, and the refrigerating capacity of the second evaporator 6 can be made constant. The refrigeration system using such a control and refrigerant circuit is particularly effective in a place where the load fluctuation is small in the refrigeration warehouse on the first evaporator side, but the refrigeration warehouse in the second evaporator is small.

Embodiment 12 FIG.
FIG. 15 shows a twelfth embodiment of the invention. For example, an electromagnetic valve 33 is provided as the fourth on-off valve 33 in the fourth bypass circuit 28 of the tenth embodiment of the invention. In normal operation, the solenoid valve 33 of the fourth bypass circuit 28 is kept open and the control is the same as in the tenth embodiment of the invention. By closing the solenoid valve 33 of the fourth bypass circuit 28 including the ejector 4, only the first evaporator 5 is operated at the time of start-up or pull-down, and a normal refrigeration cycle is achieved. During start-up or pull-down operation (during unsteady operation), fluctuations in the refrigerant flow rate are expected to be large, and it is desirable to prevent the refrigerant from flowing into the ejector until it becomes stable. Let's drive. Further, by closing the electromagnetic valve 33, the second evaporator 6 can be defrosted by stopping, and the first evaporator 5 can be operated normally. Conversely, when the first electronic expansion valve 3 is fully closed and the electromagnetic valve 33 is opened, the first evaporator 5 can be defrosted by stopping and the second evaporator 6 can be operated normally.

It is a figure which shows Embodiment 1 of this invention. 1 is a structural diagram of an ejector according to the present invention. It is the refrigerating cycle operating point on the pressure-enthalpy diagram of this invention. Is a diagram showing an _{H R10 -H R3 / H R11 -H} R4 and relationship evaporation temperature of the present invention. It is a figure which shows Embodiment 2 of this invention. It is a figure which shows Embodiment 3 of this invention. It is a figure which shows Embodiment 4 of this invention. It is a figure which shows Embodiment 5 of this invention. It is a figure which shows Embodiment 6 of this invention. It is a figure which shows Embodiment 7 of this invention. It is a figure which shows Embodiment 8 of this invention. It is a figure which shows Embodiment 9 of this invention. It is a figure which shows Embodiment 10 of this invention. It is a figure which shows Embodiment 11 of this invention. It is a figure which shows Embodiment 12 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor, 2 Condenser, 2a Condenser control means, 3 First flow control valve, 4 Ejector, 5 First evaporator, 5b Control means, 6 Second evaporator, 6a Control means, 6b Control means, 7 Air Liquid separator, 8 liquid level detecting means, 12 first on-off valve, 13 second flow rate adjusting valve, 14 on-off valve (second on-off valve), 15 bypass circuit (first bypass circuit), 16 second bypass circuit, 17 3rd flow control valve, 18 pressure detection means, 19 temperature detection means, 20 pressure detection means, 21 temperature detection means, 22 suction part, 23 bypass circuit (3rd bypass circuit), 24 flow control valve (4th flow control valve) ), 28 Bypass circuit, 29 Condensing pressure (temperature) detecting means, 31 Second evaporator pressure (temperature) detecting means, 33 On-off valve, 34 Pressure adjusting valve, 35 Pressure detecting means, 36 Temperature detecting means.
In the drawings, the same numbers indicate the same or corresponding parts.

Claims (12)

A compressor, a condenser, a first flow rate control valve, an ejector, a first evaporator, and a gas-liquid separator are connected in a pipe, and the gas-liquid separator and the suction part of the ejector are connected to the second evaporator. In a refrigeration apparatus connected via a pipe, a liquid level detection means provided in the gas-liquid separator, a bypass circuit having an on-off valve or a flow rate adjustment valve that bypasses the first evaporator, and the liquid level detection Control means for opening an on-off valve or a flow rate control valve of the bypass circuit until the refrigerant amount reaches a predetermined amount when the means detects a refrigerant amount shortage of the gas-liquid separator. Refrigeration equipment. A first on-off valve is provided in the first evaporator inlet side pipe, and a bypass circuit is connected to a pipe between the ejector and the first on-off valve, and a second pipe connected to the pipe between the first evaporator and the gas-liquid separator. A first bypass circuit having an on-off valve is provided, and when the liquid level detection means detects that the refrigerant amount in the gas-liquid separator is insufficient, the control means closes the first on-off valve until the refrigerant amount reaches a predetermined amount. and the valve, the refrigeration apparatus of claim 1, wherein by opening the second shut-off valve. A second bypass circuit having a third flow rate control valve for bypassing the first flow rate control valve and the ejector, and when the liquid level detecting means detects that the refrigerant amount of the gas-liquid separator is insufficient, the refrigerant amount is set to a predetermined amount; Until the control means opens the second on-off valve of the first bypass circuit, closes the first on-off valve and the first flow control valve of the first evaporator, the valve opening of the third flow control valve 3. The refrigeration apparatus according to claim 2 , wherein the refrigeration apparatus is adjusted and controlled. The bypass circuit is a third bypass circuit having a fourth flow rate control valve for connecting a pipe between the condenser and the first flow rate control valve and a pipe between the first evaporator and the gas-liquid separator, and a liquid level detecting means When detecting that the amount of refrigerant in the gas-liquid separator is insufficient, the control means closes the first flow rate adjustment valve until the refrigerant amount reaches a predetermined amount, and sets the valve opening degree of the fourth flow rate adjustment valve. 2. The refrigeration apparatus according to claim 1 , wherein the refrigeration apparatus is controlled. A compressor, a condenser, a first flow rate control valve, an ejector, a first evaporator, and a gas-liquid separator are connected in a pipe, and the gas-liquid separator and the suction part of the ejector are connected to the second evaporator. In the refrigeration apparatus connected via a pipe, a liquid level detecting means provided in the gas-liquid separator and an outlet side of the gas-liquid separator are connected between the gas-liquid separator and the second evaporator. A second flow rate control valve, a second bypass circuit that bypasses the first flow rate control valve and the ejector, a third flow rate control valve provided in the second bypass circuit, and the liquid level detecting means When a shortage of refrigerant in the liquid separator is detected, the first flow valve and the second flow valve are closed until the refrigerant amount reaches a predetermined amount, and the valve opening of the third flow control valve is adjusted. A refrigeration apparatus comprising a control means for adjusting. It has a nozzle part, a diffuser part, and a suction part. The high pressure refrigerant is reduced by the nozzle part and mixed with a refrigerant gas flowing from the evaporator through the suction part, and the pressure of the refrigerant is increased in the diffuser part. The ejector
A gas-liquid separator that separates refrigerant flowing out of the ejector into refrigerant gas and refrigerant liquid, supplies the refrigerant liquid to the evaporator, and supplies refrigerant gas to the compressor;
A flow control valve provided between the gas-liquid separator and the evaporator,
The gas-liquid separator is installed at a position higher than the evaporator, and the refrigerant liquid of the gas-liquid separator flows into the evaporator when the refrigeration apparatus stops. The refrigeration apparatus according to claim 6 , wherein the control means fully opens the flow rate control valve when the refrigeration apparatus is stopped. The control means is characterized in that, at startup, the flow control valve is fully closed, the superheat degree of the evaporator outlet is detected, and the flow control valve is fully closed until the superheat degree reaches a predetermined value. The refrigeration apparatus according to claim 6 . It has a nozzle part, a diffuser part, and a suction part. The high pressure refrigerant is reduced by the nozzle part and mixed with a refrigerant gas flowing from the evaporator through the suction part, and the pressure of the refrigerant is increased in the diffuser part. The ejector
A gas-liquid separator that separates refrigerant flowing out of the ejector into refrigerant gas and refrigerant liquid, supplies the refrigerant liquid to the evaporator, and supplies refrigerant gas to the compressor;
A flow control valve provided between the gas-liquid separator and the evaporator;
A bypass circuit that bypasses another flow control valve and another evaporator provided between the condenser and the gas-liquid separator,
The refrigeration apparatus, wherein the ejector is provided in the bypass circuit. First control means for detecting a condensation state of the condenser and controlling the condensation state of the condenser so that a condensation pressure or a condensation temperature of the condenser becomes a target condensation pressure or a target condensation temperature;
Second control means for controlling the flow rate adjusting valve so that the evaporation pressure or evaporation temperature of the evaporator becomes a target evaporation pressure or target evaporation temperature;
The refrigeration apparatus according to claim 9 , comprising: The refrigerating apparatus according to claim 9 , wherein the bypass circuit includes an on-off valve. A compressor, a condenser, an on-off valve, a first flow rate adjustment valve, a first evaporator, and a gas-liquid separator are connected in series, and an ejector is provided in a circuit that bypasses the first flow rate adjustment valve and the first evaporator. A pressure adjusting valve is provided between the junction of the bypass circuit and the outlet of the first evaporator to the pipe connecting the first evaporator and the gas-liquid separator, and the gas-liquid separator and the ejector suction unit In a refrigeration apparatus comprising a second flow rate control valve connected to a pipe via a second evaporator and further connected to a pipe between the gas-liquid separator and the second evaporator. A control means for detecting a condensation pressure or a condensation temperature of the condenser and controlling a condensation state of the condenser so as to reach a target condensation pressure or a target condensation temperature; a pressure detection means; and a temperature detection means. Detect the pressure and temperature at the outlet of the first evaporator And a control means for adjusting the refrigerant flow rate with the first flow rate control valve and a pressure detection means or a temperature detection means so as to achieve a target superheat degree, and detects an evaporation pressure or an evaporation temperature of the second evaporator. A refrigeration apparatus comprising control means for adjusting the refrigerant flow rate of the second flow rate control valve so as to achieve a target evaporation pressure or a target evaporation temperature.

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