CN104315741B - Mixed working fluid injection refrigeration cycle system and refrigeration cycle method - Google Patents

Abstract

The present invention relates to mixed working fluid spray type refrigerating blood circulation and refrigerating and circulating method.Wherein mixed working fluid spray type refrigerating blood circulation includes gas-liquid separator, regenerator, vaporizer and restricting element, the gas-phase working medium outlet of gas-liquid separator is connected with the hot working fluid feeder connection of regenerator and constitutes gas-phase working medium and separate condensing unit, it is provided with at least one-level secondary gas-phase working medium between hot working fluid channel outlet and the restricting element of regenerator and separates condensing unit, secondary gas-phase working medium separation condensing units at different levels all include that the secondary gas-liquid separator being connected with the hot working fluid channel outlet of regenerator in higher level and the gas-phase working medium with secondary gas-liquid separator export the secondary regenerator being connected, in most end one-level, the secondary hot working fluid channel outlet of regenerator is connected with the working medium entrance of restricting element.Above-mentioned cooling cycle system can reduce the compression ratio needed for ejector, is advantageously implemented the separation of mixed working fluid, energy-conservation, simple in construction, stable.

Description

Mixed working fluid injection refrigeration cycle system and refrigeration cycle method

technical field

The invention relates to a mixed working medium injection refrigeration cycle system and a refrigeration cycle method.

Background technique

The ejector refrigeration system is a heat-driven refrigeration system that can utilize low-grade thermal energy such as industrial waste heat, waste heat, solar energy, and geothermal energy, and can use environmentally friendly working fluids such as water, hydrocarbons, or hydrofluorocarbons, and the system Simple structure, no moving parts, high reliability. Therefore, the ejector refrigeration system is of great significance for saving energy and protecting the environment. However, the working efficiency of the ejector is closely related to the compression ratio. Increasing the compression ratio will significantly reduce the working efficiency of the ejector, that is, as the cooling temperature decreases, the efficiency of the ejector refrigeration system will decrease sharply; while the traditional ejector refrigeration cycle The compression ratio of the ejector of the system is small, and it is difficult to meet the condensing pressure required by the cooling medium of the condenser when the cooling temperature is high, so the cooling temperature of the traditional jet refrigeration cycle is relatively high. In addition, when the difference between the ejector back pressure and the injection pressure exceeds a certain value, that is, when the ejector compression ratio increases to a certain value, the injection coefficient will drop sharply, which also means that it is difficult for traditional ejector refrigeration to achieve lower cooling efficiency. temperature.

The Chinese patent with application number 201210116545.X and authorized announcement number CN 102620461 B discloses a self-cascading ejector refrigerator, which includes a first generator, a first ejector, a first condenser, a first The gas-liquid separator and the working medium pump (namely the first circulation pump), also includes the first heat regenerator (namely the condensation evaporator) and the evaporator for refrigeration. The gas-phase working medium outlet of the first gas-liquid separator is connected to the thermal working medium channel inlet of the first regenerator to form a gas-phase working medium separation and condensation device; the thermal working medium channel outlet of the first regenerator is connected to the first throttling element connected, the working fluid outlet of the first throttling element is connected with the evaporator. The liquid-phase working medium outlet of the first gas-liquid separator is divided into two paths, one is connected with the working medium pump, and the other is connected with the cold working medium channel inlet of the first regenerator through the second throttling element; The cold working medium channel outlet of the device and the working medium outlet of the evaporator are simultaneously connected with the injection fluid inlet of the working medium pump.

When working, the working fluid rich in high boiling point is heated by an external heat source in the first generator and becomes a high-pressure gas, and the working fluid rich in high boiling point at the outlet of the first generator enters the first injector as the working fluid , introducing the working fluid rich in low boiling point from the evaporator and the working fluid rich in high boiling point from the regenerator, the mixed gas is injected to boost the pressure to reach the condensation pressure, and enter the first condenser to release heat; the fluid mixture After being partially liquefied, the gas-liquid mixture enters the first gas-liquid separator, in which a part of the liquid-phase fluid rich in high-boiling point working fluid is pressurized by the working medium pump and returns to the first generator; the other part is rich in high-boiling point working fluid. The liquid phase fluid of the working medium enters the regenerator to evaporate and absorb heat after passing through the second throttling element, and then returns to the first ejector; The medium is cooled to become liquid, and after passing through the first throttling element, it enters the evaporator to evaporate and absorb heat to obtain cooling effect, and then returns to the first ejector, and the system completes a working process. The refrigerator adopts a self-cascading method to reduce the compression ratio that the refrigeration system needs to achieve, and can use jet refrigeration technology to achieve a lower refrigeration temperature. However, in the actual application process, due to the limitation of the low compression ratio of the injector, the standard boiling point of the mixed working fluid in the system cannot be too different, which makes the separation of the mixed working fluid in the system more difficult, which limits its practical application. Adopting the double-stage injection form with the second injector will cause the problems of complicated structure, high cost and poor working reliability.

Contents of the invention

The object of the present invention is to provide a mixed working medium injection refrigeration cycle system, which can reduce the compression ratio required by the ejector, and conveniently realize the separation of mixed working medium, thereby obtaining a lower refrigeration temperature; at the same time, the present invention also provides A mixed refrigerant injection refrigeration cycle method is proposed.

The technical solution adopted by the mixed working medium injection refrigeration cycle system in the present invention is: the mixed working medium injection refrigeration cycle system includes a gas-liquid separator, a regenerator, an evaporator for refrigeration and a working medium connected to the evaporator A throttling element for the inlet, the gas-phase working medium outlet of the gas-liquid separator is connected with the thermal working medium channel inlet of the regenerator to form a gas-phase working medium separation and condensation device, and the thermal working medium channel outlet of the regenerator is connected to the At least one secondary gas-phase working medium separation and condensing device is arranged between the throttling elements, and each level of the secondary gas-phase working medium separation and condensing device includes a secondary gas-phase working medium channel outlet connected to the regenerator in the upper stage. The primary gas-liquid separator and the secondary regenerator connected to the gas-phase working medium outlet of the secondary gas-liquid separator, the thermal working medium channel outlet of the secondary regenerator in the last stage and the working medium of the throttling element The liquid-phase working medium outlet of the secondary gas-liquid separator is connected with a secondary throttling element, and the working medium outlet of the secondary throttling element is connected with the cold working medium channel inlet of the secondary regenerator. The outlet of the cold working medium channel of the stage regenerator communicates with the injection fluid inlet of the ejector of the mixed working medium injection refrigeration cycle system or communicates with the inlet of the cold working medium channel of the regenerator in the upper stage.

The working medium outlet of the evaporator communicates with the cold working medium channel inlet of the secondary regenerator in the last stage or directly communicates with the injection fluid inlet of the ejector of the mixed working medium injection refrigeration cycle system.

The secondary gas-phase working medium separation and condensation device has only one stage.

The mixed working medium used in the mixed working medium injection refrigeration cycle system includes high boiling point working medium and low boiling point working medium, and the high boiling point working medium is a mixture of one or more of R134a, R600, R152a, R245fa and R600a, The low boiling point working fluid is one or a mixture of R23, R32, R290 and R143a.

The technical solution adopted by the mixed working medium injection refrigeration cycle method in the present invention is: the mixed working medium injection refrigeration cycle method, which comprises the following steps: The working fluid flowing out of the outlet of the channel passes through at least one secondary gas-phase working fluid separation and condensing device, and the secondary gas-phase working fluid separation and condensing devices at each level include a secondary gas phase connected to the thermal working medium channel outlet of the regenerator in the upper stage. The liquid separator and the secondary regenerator connected to the gas-phase working medium outlet of the secondary gas-liquid separator, and the outlet of the thermal working medium channel of the secondary regenerator in the last stage and the working medium inlet connected to the evaporator The working fluid inlet of the throttling element is connected so that the working fluid enters the evaporator for refrigeration; the liquid-phase working medium outlet of the secondary gas-liquid separator is connected with a secondary throttling element, and the working fluid outlet of the secondary throttling element is connected to the secondary The inlet of the cold working medium channel of the primary regenerator is connected, and the outlet of the cold working medium channel of the secondary regenerator is connected with the injection fluid inlet of the injector of the mixed working medium injection refrigeration cycle system or with the cooling fluid of the upper middle regenerator. The inlet of the working fluid channel is connected, and the working fluid flowing out of the outlet of the cold working medium channel of the secondary regenerator is directly ejected by the injector or ejected by the ejector after passing through the cold working medium channel of the upper secondary regenerator.

The working medium outlet of the evaporator communicates with the cold working medium channel inlet of the secondary regenerator in the last stage or directly communicates with the injection fluid inlet of the ejector of the mixed working medium injection refrigeration cycle system, and flows out of the evaporator The working fluid is directly ejected by the ejector or is ejected by the ejector after passing through the cold refrigerant channel of the secondary regenerator in the last stage.

The mixed working medium injection refrigeration cycle system is a mixed working medium single-stage injection refrigeration cycle system with only one stage ejector.

The mixed working medium used in the mixed working medium injection refrigeration cycle system includes high boiling point working medium and low boiling point working medium, and the high boiling point working medium is a mixture of one or more of R134a, R600, R152a, R245fa and R600a, The low boiling point working fluid is one or a mixture of R23, R32, R290 and R143a.

The present invention adopts the above-mentioned technical scheme, and at least one secondary gas-phase working medium separation and condensing device is provided between the thermal working medium channel outlet of the regenerator and the throttling element, and the secondary gas-phase working medium separation and condensing devices at each level include The secondary gas-liquid separator connected to the outlet of the thermal working medium channel of the upper-stage regenerator and the secondary regenerator connected to the outlet of the gas-phase working medium of the secondary gas-liquid separator, and the secondary regenerator in the last stage The outlet of the hot working medium channel of the injector is connected with the working medium inlet of the throttling element, thereby forming two stages of condensate separation, which can effectively reduce the compression ratio of the injector, and realize the separation and separation of the mixed working medium under low compression ratio conditions. Cascade, to obtain lower refrigeration temperature, improve the utilization rate of low-grade low-temperature heat source, greatly reduce the refrigeration temperature of the traditional single-stage jet refrigeration cycle, good energy saving effect, wide application range; and compared with the existing technology, this refrigeration system is In the case of the same cooling effect, there is no need to use two-stage injection, and the structure is simple, the operation is stable, and the cost is low.

Description of drawings

Fig. 1 is the structural representation of embodiment 1 of the mixed working medium injection refrigeration cycle system in the present invention;

Fig. 2 is a schematic structural diagram of Embodiment 2 of the mixed working medium injection refrigeration cycle system in the present invention.

The names corresponding to the reference signs in the figure are: 1-generator, 2-eductor, 3-cooler, 4-first gas-liquid separator, 5-first throttle valve, 6-first regenerator , 7-second gas-liquid separator, 8-second throttle valve, 9-second regenerator, 10-third throttle valve, 11-evaporator, 12-working medium pump.

detailed description

Embodiment 1 of the mixed working medium ejector refrigeration cycle system in the present invention is shown in Figure 1, comprising a generator 1, an ejector 2, a cooler 3, a first gas-liquid separator 4 and a working medium pump 12 connected in sequence, It also includes a first throttling valve 5 , a first regenerator 6 , an evaporator 11 for refrigeration and a third throttling valve 10 connected to the working medium inlet of the evaporator 11 .

The liquid-phase working medium outlet of the first gas-liquid separator 4 is divided into two paths, one of which is connected to the working medium pump 12 and the other is connected to the first throttle valve 5 . The first regenerator 6 has a cold working medium channel and a hot working medium channel. The inlet of the cold working medium channel of the first regenerator 6 is connected to the working medium outlet of the first throttle valve 5, and the outlet of the cold working medium channel is connected to the injector. 2 is connected to the injection fluid inlet. The gas-phase working medium outlet of the first gas-liquid separator 4 is connected to the thermal working medium channel inlet of the first regenerator 6 to form a gas-phase working medium separation and condensation device. A secondary gas-phase working medium separation and condensing device is provided between the thermal working medium channel outlet of the first regenerator 6 and the third throttle valve 10, and the secondary gas-phase working medium separation and condensing device includes a second gas-liquid separator 7 And the second regenerator 9, the second gas-liquid separator 7 is connected to the outlet of the thermal working medium channel of the first regenerator 6, and the second regenerator 9 is connected to the gas phase working medium outlet of the second gas-liquid separator 7 , the second gas-liquid separator 7 and the second regenerator 9 respectively constitute a secondary gas-liquid separator and a secondary regenerator.

The liquid-phase working medium outlet of the second gas-liquid separator 7 is connected with a second throttle valve 8 as a secondary throttling element, and the working medium outlet of the second throttle valve 8 is connected with the cold working medium of the second regenerator 9 The channel inlet is connected, the cold working medium channel outlet of the second regenerator 9 is connected with the cold working medium channel inlet of the first regenerator 6; the hot working medium channel outlet of the second regenerator 9 is connected with the third throttle valve 10 The working fluid inlet connection. The working medium outlet of the evaporator 11 communicates with the cold working medium channel inlet of the second regenerator 9 . In order to improve heat exchange efficiency, both the first regenerator 6 and the second regenerator 9 adopt counter-flow heat exchange, that is, the flow direction of the hot working medium channel is opposite to that of the cold working medium channel.

The mixed working medium used in the mixed working medium injection refrigeration cycle system includes high boiling point working medium and low boiling point working medium, and the high boiling point working medium is a mixture of one or more of R134a, R600, R152a, R245fa and R600a , the low boiling point working fluid is one or a mixture of R23, R32, R290 and R143a.

When working, the liquid mixed working medium in the generator 1 is heated and vaporized into a high-pressure superheated working medium steam, which enters the ejector 2 as working gas to eject the cold working medium channel outlet (low pressure side outlet) of the first regenerator 6 Low-pressure mixed working medium steam. The injected low-pressure mixed working medium steam is mixed and pressurized by the injector 2, and becomes a superheated mixed working medium steam at the outlet of the injector 2, and then enters the cooler 3 and becomes a vapor-liquid two-phase mixture after heat exchange. The working medium enters the first gas-liquid separator 4 to separate the gas and liquid phases. After separation, the gaseous phase is composed of low-boiling point working fluid and high-boiling point working medium, and the liquid phase is composed of high-boiling point working fluid and a small amount of low-boiling point working medium. The liquid-phase working fluid at the bottom of the first gas-liquid separator 4 is divided into two paths, one path is pressurized by the working fluid pump 12 and then enters the generator 1 to be heated and vaporized to become the working fluid of the ejector 2, and the other path enters the first throttle valve 5 Throttling and pressure reduction; the gas phase working medium at the top of the first gas-liquid separator 4 enters the first regenerator 6 to exchange heat with the mixed working medium from the first throttle valve 5 and the low pressure side of the second regenerator 9 , and the high-pressure gas phase The saturated working medium steam is cooled into a vapor-liquid two-phase working medium and then enters the second gas-liquid separator 7 to separate the gas phase and the liquid phase again. After separation, the gaseous phase is composed of low-boiling point working fluid and a small amount of high-boiling point working medium, and the liquid phase is composed of high-boiling point working fluid and a small amount of low-boiling point working medium. The liquid-phase working medium flowing out from the bottom of the second gas-liquid separator 7 enters the second throttle valve 8 to throttle and reduce pressure, and the gas-phase working medium flowing out from the top of the second gas-liquid separator 7 enters the second regenerator 9 and comes from the second section. The mixed working medium in the flow valve 8 and the evaporator 11 performs heat exchange, and the gas phase working medium in the intermediate pressure state condenses, and the condensed liquid working medium enters the third throttle valve 10 to throttle and become a low-temperature and low-pressure working medium, and then enters the evaporator 11 for evaporation Endothermic refrigeration, the low-pressure working medium steam flowing out of the evaporator 11 is mixed with the working medium at the outlet of the second throttle valve 8, and after heat exchange through the second regenerator 9, it is mixed with the working medium behind the first throttle valve 5 After mixing, it enters the first regenerator 6 for heat exchange and becomes a low-pressure superheated working medium steam, which is introduced into the ejector 2 by the high-pressure working medium steam from the generator 1 . Through the above-mentioned cycle process, the low-temperature refrigeration temperature is obtained in the evaporator 11, and the low-temperature deep refrigeration below -40°C can be realized. The above cycle process is also the first embodiment of the mixed working medium injection refrigeration cycle method in the present invention.

The second embodiment of the mixed working medium injection refrigeration cycle system in the present invention is shown in Figure 2, and the difference from the first embodiment is that in this embodiment, the outlet of the cold working medium channel of the second regenerator 9 is directly connected to the The injection fluid inlet of the injector 2 is connected, and the working medium outlet of the evaporator 11 is also directly connected with the injection fluid inlet of the injector 2 .

When working, the liquid mixed working medium in the generator 1 is heated and vaporized into high-pressure superheated working medium steam, which enters the injector 2 as the working fluid and injects it from the outlet of the cold working medium channel of the first regenerator 6 (low-pressure side outlet), the second The low-pressure working medium at the outlet of the low-pressure side of the regenerator 9 and the outlet of the evaporator 11 is mixed and pressurized by the ejector 2, and the mixed working medium vapor at the outlet of the ejector 2 enters the cooler 3 and is cooled to a lower temperature gas. The liquid two-phase mixed working medium, the vapor-liquid two-phase mixed working medium enters the first gas-liquid separator 4 to realize the separation of the gas phase and the liquid phase, the liquid phase working medium at the bottom of the first gas-liquid separator 4 is divided into two paths, and one path passes After the pump 12 is pressurized, it enters the generator 1 to be heated and vaporized to become the working fluid of the injector 2, and the other way enters the first throttle valve 5 to throttle and reduce the pressure, and then exchange with the gas phase working fluid from the top of the first gas-liquid separator 4 Heat, low-pressure liquid working medium evaporates, high-pressure gas-phase working medium is cooled to lower temperature gas-liquid two-phase mixed working medium enters the second gas-liquid separator 7 to realize gas phase and liquid phase separation again, after separation, the gas phase part is low boiling point working medium refrigerant and a small amount of high-boiling-point working fluid, the liquid phase part is high-boiling-point working fluid and a small amount of low-boiling-point working fluid, and the gas-phase working medium flowing out from the top of the second gas-liquid separator 7 enters the second regenerator 9 and comes from the second throttle valve 8 The low-pressure working fluid performs heat exchange, the high-pressure gas-phase working medium condenses, and the condensed high-pressure liquid working medium enters the third throttling valve 10 to throttle to become a low-temperature and low-pressure working medium, and then enters the evaporator 11 to evaporate, absorb heat and refrigerate, and the second throttling The low-pressure gas-liquid two-phase working medium at the outlet of valve 8 absorbs heat and evaporates in the second regenerator 9, and the low-pressure working medium steam at the outlet of evaporator 11, the outlet of the cold working medium channel of the first regenerator 6 (low-pressure side outlet) The working medium steam is mixed and injected into the injector 2 by the high-pressure working medium steam from the generator 1. Through the above-mentioned cycle process, the low-temperature refrigeration temperature is obtained in the evaporator 11, and the low-temperature deep refrigeration below -40°C can be realized. The above cycle process is also the second embodiment of the mixed working medium injection refrigeration cycle method in the present invention.

In the above embodiments, the mixed working medium injection refrigeration cycle system is a mixed working medium single-stage injection refrigeration cycle system with only one stage of ejector, and the secondary gas phase working medium separation and condensing device is only provided with one stage. In other embodiments of the present invention, the mixed working medium injection refrigeration cycle system can also adopt the two-stage injection in the prior art to achieve better refrigeration effect, and the secondary gas phase working medium separation and condensation device can also be provided with two stages above. In addition, in other embodiments, the liquid-phase working medium outlets of each gas-liquid separator can also be replaced with other connection methods, for example, connecting the liquid-phase working medium outlet of the second gas-liquid separator 7 to the first regenerator 6 The working fluid inlet is connected. Furthermore, the regenerators in the gas-phase working medium separation and condensing devices at each stage in the above embodiment can also be replaced with other forms, such as using an external cold source to exchange heat with the working medium passing through the hot working medium channel, or using other stages The working fluid flowing out of the liquid phase working medium outlet of the gas-liquid separator in the gas-phase working medium separation and condensing device exchanges heat with the working medium passing through the hot working medium channel.

Claims (8)

1. Mixed working medium injection refrigeration cycle system, including a gas-liquid separator, a regenerator, an evaporator for refrigeration and a throttling element connected to the working medium inlet of the evaporator, the gas phase of the gas-liquid separator The gas outlet is connected to the inlet of the thermal medium channel of the regenerator to form a gas-phase working medium separation and condensation device, which is characterized in that at least one Secondary gas-phase working medium separation and condensing devices, the secondary gas-phase working medium separation and condensing devices at each level include a secondary gas-liquid separator connected to the outlet of the thermal working medium channel of the regenerator in the upper stage and a secondary gas-liquid separator connected to the outlet of the secondary gas-liquid The secondary regenerator connected to the gas-phase working medium outlet of the separator, the thermal working medium channel outlet of the secondary regenerator in the last stage is connected to the working medium inlet of the throttling element; the secondary gas-liquid separation The liquid-phase working medium outlet of the regenerator is connected with a secondary throttling element, the working fluid outlet of the secondary throttling element is connected with the cold working medium channel inlet of the secondary regenerator, and the cold working medium channel outlet of the secondary regenerator is connected with the The injection fluid inlet of the ejector of the mixed working medium injection refrigeration cycle system is connected or communicated with the cold working medium channel inlet of the regenerator in the upper stage. 2. The mixed working medium injection refrigeration cycle system according to claim 1, characterized in that: the working medium outlet of the evaporator communicates with the cold working medium channel inlet of the secondary regenerator in the last stage or directly It communicates with the injection fluid inlet of the ejector of the mixed working medium injection refrigeration cycle system. 3. The mixed working medium injection refrigeration cycle system according to claim 1, wherein the secondary gas phase working medium separation and condensing device is provided with only one stage. 4. The mixed working medium injection refrigeration cycle system according to claim 1, characterized in that: the mixed working medium used in the mixed working medium injection refrigeration cycle system includes a high boiling point working medium and a low boiling point working medium, and the high boiling point The working medium is a mixture of one or more of R134a, R600, R152a, R245fa and R600a, and the low boiling point working medium is a mixture of one or more of R23, R32, R290 and R143a. 5. The mixed working medium injection refrigeration cycle method is characterized in that the method includes the following steps: passing the working fluid flowing out from the outlet of the hot working medium channel of the regenerator in the mixed working medium injection refrigeration cycle system through at least one secondary The gas-phase working medium separation and condensing device, the secondary gas-phase working medium separation and condensing devices at each level include a secondary gas-liquid separator connected to the outlet of the thermal working medium channel of the regenerator in the upper stage and a secondary gas-liquid separator connected to the outlet of the secondary gas-liquid separator. The secondary regenerator connected to the gas-phase working medium outlet, the outlet of the thermal working medium passage of the secondary regenerator in the last stage is connected to the working medium inlet of the throttling element connected to the working medium inlet of the evaporator so that the working medium into the evaporator for refrigeration; the liquid-phase working medium outlet of the secondary gas-liquid separator is connected with a secondary throttling element, and the working medium outlet of the secondary throttling element is connected with the cold working medium channel inlet of the secondary regenerator, The outlet of the cold working medium channel of the secondary regenerator communicates with the injection fluid inlet of the ejector of the mixed working medium injection refrigeration cycle system or communicates with the inlet of the cold working medium channel of the upper stage regenerator, and flows out of the secondary regenerator The working fluid at the outlet of the cold working medium channel is directly ejected by the ejector or is ejected by the ejector after passing through the cold working medium channel of the upper secondary regenerator. 6. The mixed working medium injection refrigeration cycle method according to claim 5, characterized in that: the working medium outlet of the evaporator communicates with the cold working medium channel inlet of the secondary regenerator in the last stage or directly It is connected with the injection fluid inlet of the injector of the mixed working medium injection refrigeration cycle system, and the working fluid flowing out of the evaporator is directly injected by the injector or passed through the cold working medium channel of the secondary regenerator in the last stage. The ejector ejects. 7. The mixed working medium injection refrigeration cycle method according to claim 5, characterized in that: the mixed working medium injection refrigeration cycle system is a mixed working medium single-stage injection refrigeration cycle system with only one stage ejector. 8. The mixed working medium injection refrigeration cycle method according to claim 5, characterized in that: the mixed working medium used in the mixed working medium injection refrigeration cycle system includes a high boiling point working medium and a low boiling point working medium, and the high boiling point The working medium is a mixture of one or more of R134a, R600, R152a, R245fa and R600a, and the low boiling point working medium is a mixture of one or more of R23, R32, R290 and R143a.