Ejector Refrigeration System

This application claims benefit of Chinese Patent Application No. 202410390088.6, filed Apr. 1, 2024, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in their entirety are herein incorporated by reference.

This application relates to the field of refrigeration devices, and particularly, to an ejector refrigeration system.

This application provides an ejector refrigeration system to resolve or alleviate some of the problems in the prior art.

A first aspect of this application provides an ejector refrigeration system including: a compressor having a suction port and a discharge port; a first heat exchanger connected to the discharge port of the compressor to receive a fluid working medium flowing out from the discharge port of the compressor; and an ejector including a primary flow inlet connected to the first heat exchanger to receive a fluid working medium from the first heat exchanger, a secondary flow inlet, and an ejector outlet connected to the suction port of the compressor to return a fluid working medium entering the ejector to the suction port of the compressor. The ejector refrigeration system further includes a phase adjustment mechanism configured to adjust a phase state of the fluid working medium entering the primary flow inlet of the ejector.

In one or more embodiments, the phase adjustment mechanism is configured to adjust the fluid working medium entering the primary flow inlet of the ejector into a gas-liquid two-phase state in response to an external ambient temperature being lower than a specified value.

In one or more embodiments, the ejector refrigeration system further includes: a second heat exchanger; and a gas-liquid separator including an inlet connected to the ejector outlet, a gas outlet connected to the suction port of the compressor, and a liquid outlet connected to the secondary flow inlet via the second heat exchanger.

In one or more embodiments, the ejector refrigeration system further includes a differential pressure sensor configured to measure a differential pressure between the secondary flow inlet of the ejector and the ejector outlet, the phase adjustment mechanism being in communication connection with the differential pressure sensor, or the ejector refrigeration system further includes a pressure detection assembly configured to detect pressures of the ejector outlet and the secondary flow inlet, the phase adjustment mechanism being in communication connection with the pressure detection assembly.

In one or more embodiments, the ejector refrigeration system further includes: a dryness sensor disposed at the primary flow inlet, the phase adjustment mechanism being in communication connection with the dryness sensor.

In one or more embodiments, the ejector refrigeration system further includes an expansion valve disposed between the primary flow inlet and the first heat exchanger, in which the phase adjustment mechanism is a mechanism for controlling an opening degree of the expansion valve.

In one or more embodiments, the phase adjustment mechanism is a mechanism for controlling a rotation speed of a fan of the first heat exchanger.

In one or more embodiments, the ejector refrigeration system further includes: a bypass pipeline connected, at one end, between the discharge port of the compressor and the first heat exchanger, and connected, at the other end, between an outlet of the first heat exchanger and the primary flow inlet; and a first opening regulating valve disposed in the bypass pipeline, in which the phase adjustment mechanism is a mechanism for adjusting an opening degree of the first opening regulating valve.

In one or more embodiments, the ejector refrigeration system further includes a reservoir including: a reservoir inlet communicating with a first pipe section of the first heat exchanger to receive a fluid working medium at an outlet of the first pipe section; a reservoir liquid refrigerant outlet communicating with a second pipe section of the first heat exchanger; and a reservoir gaseous refrigerant outlet located at the top of the reservoir and connected between an outlet of the first heat exchanger and the primary flow inlet of the ejector.

In one or more embodiments, the ejector refrigeration system further includes a second opening regulating valve disposed between the reservoir gaseous refrigerant outlet and the primary flow inlet, in which the phase adjustment mechanism is a mechanism for adjusting an opening degree of the second opening regulating valve.

The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application, and obviously, the described embodiments are merely a part of the embodiments of this application, and are not all embodiments.

Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of this application.

As illustrated in, an ejector refrigeration system of existing configurations using carbon dioxide as a fluid working medium and using an ejector is disclosed.

In the ejector refrigeration system, the fluid working medium from a compressorenters an ejectorthrough a first heat exchanger, the fluid working medium entering through a second heat exchanger(evaporator) is mixed in the ejectorand then enters a gas-liquid separator. After the gas-liquid separation, a gaseous working medium returns to the compressor, the liquid working medium enters the second heat exchanger(evaporator) again, the second heat exchangerexchanges heat with, for example, external air, so that a temperature of the external air is decreased to achieve a refrigeration effect.

However, when an external ambient temperature is relatively low, since a fluid pressure at an outlet of the first heat exchangeris excessively low, the ejectorcannot provide sufficient pressure lift, and a working medium pressure at an outlet of the ejectorcannot be raised to a specified pressure, which greatly reduces an effect of the ejectorin the ejector refrigeration system and can cause the ejector refrigeration system to malfunction and fail to operate normally. Further, there are problems of reduced refrigeration energy efficiency, complex structure and high cost.

The one or more embodiments of the present disclosure provide an ejector refrigeration system which increases reliability, improves refrigeration energy efficiency, provides a less complex structure, and facilitates system wide cost reductions.

As illustrated in, a first aspect of this application provides an ejector refrigeration system including a compressor, a first heat exchanger, an ejector, a phase adjustment mechanism (not illustrated), a second heat exchanger, a gas-liquid separatorand a throttle valve. The compressorhas a suction portand a discharge port. The first heat exchangeris connected to the discharge portof the compressorto receive a fluid working medium flowing out from the discharge portof the compressor. The ejectorincludes a primary flow inlet, a secondary flow inletand an ejector outlet, the primary flow inletis connected to the first heat exchangerto receive a fluid working medium from the first heat exchanger, and the ejector outletis connected to the suction portof the compressorto return a fluid working medium entering the ejectorto the suction portof the compressor. The phase adjustment mechanism adjusts a phase state of the fluid working medium entering the primary flow inletof the ejector, and specifically adjusts the fluid working medium entering the primary flow inletof the ejectorto a gas-liquid two-phase state or adjusts the content of a gaseous working medium in the gas-liquid two-phase state.

The gas-liquid separatoris disposed between the ejectorand the compressor. The gas-liquid separatorincludes an inlet, a gas outletand a liquid outlet. The inletof the gas-liquid separatoris connected to the ejector outlet, and the gas outletis connected to the suction portof the compressor. The liquid outletis connected to the secondary flow inletvia the second heat exchanger, and the throttle valveis disposed between the liquid outletand the second heat exchanger.

The ejector refrigeration system of this application includes a first loop and a second loop. In the first loop, the gaseous working medium discharged from the compressorsequentially passes through the first heat exchanger, the ejector, and the gas-liquid separatorand then returns to the compressor. In the second loop, a liquid working medium discharged from the liquid outletof the gas-liquid separatorsequentially passes through the throttle valve, the second heat exchanger, and the secondary flow inletof the ejectorand then returns to the inletof the gas-liquid separator.

It should be noted that the ejector refrigeration system in this application may perform heating operation in addition to cooling operation.

The term “connected” in this application may refer to a direct connection or an indirect connection

The fluid working medium in this application is carbon dioxide, which has inexpensive, non-flammable, non-toxic and good environmental characteristics.

The fluid working medium at the outlet of the compressoris gaseous carbon dioxide in a subcritical state (carbon dioxide is at a temperature lower than 31.1° C. and a pressure lower than 7.38 MPa).

The ejectorincludes a nozzle, a mixing chamber, a diffuser and a suction chamber. The nozzle is configured to convert pressure energy of the fluid working medium into kinetic energy and suction the gaseous working medium entering from the suction chamber, the mixing chamber is configured to mix the gaseous working medium suctioned by the suction chamber with the fluid working medium ejected from the nozzle, and the diffuser is configured to convert the kinetic energy of the mixed fluid working medium into pressure energy for discharge.

The structure of the ejectoris a common application form in the art, and details are not described herein again.

In some embodiments of this application, the first heat exchangeris a gas cooler, the second heat exchangeris an evaporator, and the gas-liquid separatoris configured to separate the gaseous working medium from the liquid working medium, and may be a flash tank or another mechanism that can separate the gaseous working medium from the liquid working medium. This application does not limit the specific structural form of the gas-liquid separator, and those skilled in the art can select a suitable gas-liquid separatoras needed.

A phase adjustment mechanism adjusts the fluid working medium entering the primary flow inletof the ejectorto a gas-liquid two-phase state or adjusts the content of the gaseous working medium in the gas-liquid two-phase state.

Specifically, under a first working condition, the fluid working medium entering the first heat exchangeris completely cooled to a liquid state, and the fluid working medium entering the primary flow inletis in a purely liquid state. Under the first working condition, the phase adjustment mechanism adjusts a phase state of the fluid working medium entering the primary flow inletof the ejector, which specifically refers to adjusting the fluid working medium of the primary flow inletto a gas-liquid two-phase state.

Under a second working condition, the fluid working medium discharged by the first heat exchangeris a mixed working medium of the liquid working medium and a small amount of gaseous working medium. Under the second working condition, the phase adjustment mechanism adjusts the phase state of the fluid working medium entering the primary flow inletof the ejector, which specifically refers to adjusting the content of the gaseous working medium in the fluid working medium at the primary flow inlet, such as increasing the content of the gaseous working medium in the fluid working medium.

In some cases, adjusting the phase state of the fluid working medium entering the primary flow inletof the ejectormay also be understood as adjusting the content of the gaseous working medium in the fluid working medium entering the primary flow inlet.

In this application, the phase adjustment mechanism adjusts the fluid working medium entering the primary flow inletof the ejectorto the gas-liquid two-phase state or increases the content of the gaseous working medium in the gas-liquid two-phase state, thereby ensuring that the ejectorcan generate sufficient pressure lift and enabling the uninterrupted operation of the ejector refrigeration system.

In addition, since the gaseous working medium discharged from the first heat exchangeris a fluid working medium circulating inside the ejector refrigeration system, there is no need to introduce an additional fluid working medium, which reduces energy consumption and is conducive to cost savings.

In this application, the ejector refrigeration system further includes an ambient temperature sensor (not illustrated) configured to detect an external ambient temperature.

The phase adjustment mechanism is configured to adjust the fluid working medium entering the primary flow inletof the ejectorto a gas-liquid two-phase state in response to the external ambient temperature being lower than a specified value (for example, the external ambient temperature is lower than 15° C.).

In this application, when the external ambient temperature is lower than the specified value, the pressure of the fluid working medium at the outlet of the first heat exchangerdecreases relatively, resulting in the ejectorbeing unable to provide sufficient pressure lift to ensure the normal operation of the second loop.

By adjusting the fluid working medium entering the primary flow inletof the ejectorto the gas-liquid two-phase state, the pressure lift of the ejectorcan be increased.

Compared with a case where the fluid working medium entering the primary flow inletof the ejectoris entirely in the liquid state and the pressure at the primary flow inletis relatively low when the external ambient temperature is lower than the specified value, this application includes the fluid working medium that is partly the gaseous working medium, which is beneficial for ensuring the pressure lift of the ejectorand the uninterrupted operation of the ejector refrigeration system.

Further, the ejector refrigeration system further includes a differential pressure sensorconfigured to measure a differential pressure between the secondary flow inletof the ejectorand the ejector outlet, and the phase adjustment mechanism is in communication connection with the differential pressure sensor.

In this application, the phase adjustment mechanism may adjust, based on a differential pressure detection result of the differential pressure sensor, the fluid working medium entering the primary flow inletto a gas-liquid two-phase state or adjust the content of the gaseous working medium in the gas-liquid two-phase state.

Specifically, according to different differential pressure detection results, the fluid working medium entering the primary flow inletis adjusted to the gas-liquid two-phase state or the content of the gaseous working medium in the gas-liquid two-phase state is adjusted to ensure the pressure lift of the ejector, thereby avoiding a situation where the ejectorcannot work normally due to the excessive or small amount of the gaseous working medium, and improving operation reliability of the ejector refrigeration system.

A differential pressure between a working medium pressure at the ejector outletand a working medium pressure at the secondary flow inletis large, which indicates that the pressure lift of the ejectoris large, and thus the content of the gaseous working medium at the primary flow inletcan be reduced.

The differential pressure between the working medium pressure at the ejector outletand the working medium pressure at the secondary flow inletis small, which indicates that the pressure lift of the ejectoris small, and thus the pressure lift of the ejectorneeds to be increased by increasing the content of the gaseous working medium in the fluid working medium at the primary flow inlet.

In some embodiments, pressure sensors may also be respectively disposed at the secondary flow inletand the ejector outletto form a pressure detection assembly, so as to detect the pressure at the secondary flow inletand the pressure at the ejector outlet, and the phase adjustment mechanism adjusts the fluid working medium of the primary flow inletto the gas-liquid two-phase state or adjusts the content of the gaseous working medium in the gas-liquid two-phase state according to the differential pressure between the secondary flow inletand the ejector outlet.

This application does not limit a method for acquiring the differential pressure, and those skilled in the art may select a suitable differential pressure detection structure as needed.

In some embodiments, a dryness sensor (not illustrated) may be disposed at the primary flow inletto detect the content of the gaseous working medium in the fluid working medium at the primary flow inlet.