阅读说明：本技术 一种制冷系统及其控制方法 (Refrigerating system and control method thereof ) 是由 姚亚明 卫广穹 黎华斌 姚书荣 于 2020-04-28 设计创作，主要内容包括：本发明提供一种制冷系统及其控制方法,制冷系统包括：压缩机、冷凝器、冷冻蒸发器和冷藏蒸发器以及第一管路和第二管路,第一管路的一端与冷凝器连通、另一端与低压吸气口连通,第二管路的一端与冷凝器连通、另一端与中压吸气口连通,第一管路上位于冷冻蒸发器的上游还设置有第一节流装置,第二管路上位于冷藏蒸发器的上游还设置有第二节流装置。根据本发明能够使得在同一制冷系统中同时实现两个不同蒸发温度的制冷冷藏和冷冻,本申请蒸发结束后的压缩机吸气过热度大大降低,降低了排气温度,降低了压缩机耗功,同时由于处于潜热状态换热,其制冷冷量大幅提高、能够有效满足冷藏用冷量。(The invention provides a refrigeration system and a control method thereof, wherein the refrigeration system comprises: the refrigeration system comprises a compressor, a condenser, a freezing evaporator, a refrigeration evaporator, a first pipeline and a second pipeline, wherein one end of the first pipeline is communicated with the condenser, the other end of the first pipeline is communicated with a low-pressure air suction port, one end of the second pipeline is communicated with the condenser, the other end of the second pipeline is communicated with a medium-pressure air suction port, a first throttling device is further arranged on the first pipeline at the upstream of the freezing evaporator, and a second throttling device is further arranged on the second pipeline at the upstream of the refrigeration evaporator. According to the invention, refrigeration, cold storage and freezing at two different evaporation temperatures can be simultaneously realized in the same refrigeration system, the suction superheat degree of the compressor after evaporation is greatly reduced, the exhaust temperature is reduced, the power consumption of the compressor is reduced, and meanwhile, the refrigeration capacity is greatly improved due to heat exchange in a latent heat state, and the refrigeration capacity for refrigeration can be effectively met.)

1. A refrigeration system, characterized by: the method comprises the following steps:

the refrigeration compressor comprises a compressor (1), a condenser (2), a freezing evaporator (3), a refrigeration evaporator (4), a first pipeline (101) and a second pipeline (102), wherein the freezing evaporator (3) is arranged on the first pipeline (101), the refrigeration evaporator (4) is arranged on the second pipeline (102), the compressor (1) is provided with a low-pressure suction port (11) and a medium-pressure suction port (12), one end of the first pipeline (101) is communicated with the condenser (2), the other end of the first pipeline is communicated with the low-pressure suction port (11), one end of the second pipeline (102) is also communicated with the condenser (2), the other end of the second pipeline is communicated with the medium-pressure suction port (12), and a first throttling device (51) is further arranged on the first pipeline (101) and positioned at the upstream position of the freezing evaporator (3) along the flow of a refrigerant, the second pipeline (102) is also provided with a second throttling device (52) at the position of the refrigerating evaporator (4) upstream along the flow of the refrigerant.

2. The refrigeration system of claim 1, wherein:

the first pipeline (101) is communicated with the second pipeline (102) and then communicated to the condenser (2), a first proportional regulating three-way valve (61) is arranged at the position where the first pipeline (101) is communicated with the second pipeline (102), and the first proportional regulating three-way valve (61) can regulate the flow of refrigerant entering the first pipeline (101) and the flow of refrigerant flowing into the second pipeline (102).

3. The refrigeration system of claim 2, wherein:

and a liquid storage device (7) and/or a drying filter (8) are/is further arranged on a pipeline between the condenser (2) and the first proportional control three-way valve (61).

4. A refrigeration system according to any one of claims 1 to 3, wherein:

the refrigeration system is characterized by further comprising a third pipeline (103), wherein one end of the third pipeline (103) is communicated to the first pipeline (101) and is located between the freezing evaporator (3) and the first throttling device (51), and the other end of the third pipeline (103) penetrates through the refrigeration evaporator (4) and is then communicated to the first pipeline (101) and is located between the freezing evaporator (3) and the compressor (1), so that the refrigerant in the third pipeline (103) exchanges heat in the refrigeration evaporator (4).

5. The refrigeration system of claim 4, wherein:

a second proportional three-way valve (62) is also arranged on the third pipeline (103) and the first pipeline (101) at the position communicated between the refrigeration evaporator (3) and the first throttling device (51).

6. The refrigeration system according to any one of claims 1 to 5, wherein:

the first throttling device (51) is an electronic expansion valve; and/or the second throttling device (52) is an electronic expansion valve; and/or, when a first proportional regulating three-way valve (61) is further included, the first proportional regulating three-way valve (61) is an electric proportional regulating three-way valve; and/or, when a second proportional three-way valve (62) is further included, the second proportional three-way valve (62) is an electric proportional three-way valve.

7. A control method applicable to the refrigeration system according to any one of claims 1 to 6, characterized in that: when a first proportional adjustment three-way valve (61) is included, the control method includes:

a detection step, which is used for detecting the pressure of a medium-pressure air suction port of the compressor, detecting the refrigerant pressure of an outlet of the refrigeration evaporator on a second pipeline and detecting the opening degree of a second throttling device;

judging whether the pressure of a refrigerant at the outlet of the refrigeration evaporator is smaller than the pressure of the medium-pressure air suction port or not, and simultaneously judging the relationship between the opening degree of the second throttling device and the maximum opening degree of the second throttling device;

a control step of controlling the opening of the first proportional control three-way valve (61) to increase the flow rate of the refrigerant flowing into the second pipe line (102) when the refrigerant pressure at the outlet of the refrigeration evaporator is smaller than the pressure at the medium-pressure suction port and the opening of the second throttle device is equal to the maximum opening; when the pressure of the refrigerant at the outlet of the refrigeration evaporator is larger than the pressure of the medium-pressure suction port and when the opening degree of the second throttling device is smaller than the maximum opening degree, controlling and adjusting the opening degree of the first proportional adjustment three-way valve (61) to reduce the flow rate of the refrigerant flowing into the second pipeline (102); when the pressure of the refrigerant at the outlet of the refrigeration evaporator is equal to the pressure of the medium-pressure suction port, the opening degree of the first proportional regulating three-way valve (61) is controlled and regulated to be unchanged.

8. The control method according to claim 7, characterized in that:

the control step is also used for controlling and adjusting the opening degree of the second throttling device to increase when the refrigerant pressure at the outlet of the refrigeration evaporator is smaller than the pressure of the medium-pressure suction port and the opening degree of the second throttling device is smaller than the maximum opening degree; and/or the control step is also used for controlling and regulating the opening degree of the second throttling device (52) to be reduced when the pressure of the refrigerant at the outlet of the refrigeration evaporator is larger than the pressure of the medium-pressure suction port and the opening degree of the second throttling device is equal to the maximum opening degree.

9. The control method according to claim 7, characterized in that:

when a second proportional three-way valve (62) is included, the control method further includes:

the detection step is also used for detecting the actual working condition temperature of the refrigeration evaporator and detecting the opening degree of the second throttling device;

the judging step is also used for judging the size relationship between the actual working condition temperature of the refrigeration evaporator and a preset temperature value and simultaneously judging the relationship between the opening size of the second throttling device and the maximum opening size of the second throttling device;

a control step of controlling and adjusting the opening of the second proportional control three-way valve (62) to increase the flow rate of the refrigerant flowing into the third pipeline (103) when the actual working condition temperature of the refrigeration evaporator is greater than a preset temperature value and the opening of the second throttling device is equal to the maximum opening; when the actual working condition temperature of the refrigeration evaporator is lower than a preset temperature value, controlling and adjusting the opening degree of the second proportional control three-way valve (62) to increase and decrease the flow rate of the refrigerant flowing into the third pipeline (103); and when the actual working condition temperature of the refrigeration evaporator is equal to the preset temperature value, controlling and adjusting the opening of the second proportional control three-way valve (62) to be unchanged.

10. The control method according to claim 9, characterized in that:

the control step is also used for controlling and adjusting the opening degree of the second proportional control three-way valve (62) to be reduced to 0 when the actual working condition temperature of the refrigeration evaporator is smaller than a preset temperature value, so that the flow rate of the refrigerant flowing into the third pipeline (103) is 0; and/or the presence of a gas in the gas,

the control step is also used for controlling and adjusting the opening degree of the second proportional control three-way valve (62) to be reduced to 0 and controlling the opening degree of the second throttling device to be reduced when the actual working condition temperature of the refrigeration evaporator is smaller than a preset temperature value; and/or the presence of a gas in the gas,

and the control step is also used for controlling and adjusting the opening of the second throttling device (52) to increase when the actual working condition temperature of the refrigeration evaporator is greater than a preset temperature value and the opening of the second throttling device is smaller than the maximum opening.

Technical Field

The invention relates to the technical field of refrigeration, in particular to a refrigeration system and a control method thereof.

Background

The existing conventional refrigerating unit has a single function, has a specific working condition temperature range, is also a specific use condition in the use process, selects different machine types to meet different working condition temperatures, and needs to be provided with a specific refrigerating unit and a specific refrigerating unit when the requirements of freezing and refrigerating are met. When the conventional refrigerating unit is used in the aspect of freezing and refrigeration, the refrigerant of the system can be throttled to a very low pressure, the refrigerant is firstly subjected to heat exchange through the freezing heat exchanger to become gas with small superheat, the refrigerant coming out of the freezing heat exchanger flows through the refrigerating heat exchanger to exchange heat, the refrigerant coming out of the refrigerating heat exchanger flows back to the suction port of the compressor, and passes through the refrigerating heat exchanger, the superheat degree of the refrigerant becomes very high, the exhaust temperature of the system can be increased, and the power consumption can be increased. Meanwhile, the heat exchange amount of the heat exchanger for refrigeration is carried out only by the sensible heat temperature difference of the refrigerant, the prepared cold amount is limited, and when the load becomes larger, the refrigeration function is difficult to meet.

The refrigeration system in the prior art usually adopts two systems to respectively finish refrigeration and low-temperature refrigeration when refrigeration and freezing are needed, the structure is complex, the cost is high, and if one system is adopted to simultaneously realize refrigeration and freezing, the technical problems that the suction superheat degree of a compressor suction port is very high due to the serial connection of a refrigeration heat exchanger and a refrigeration heat exchanger, the exhaust temperature is very high, the power consumption is increased, the refrigeration heat exchanger exchanges heat in a sensible heat state, the refrigeration cold quantity is limited, the refrigeration function cannot be met and the like exist.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to overcome the defect that the same refrigeration system in the prior art cannot realize refrigeration and freezing at the same time and can ensure low power consumption, thereby providing a refrigeration system and a control method thereof.

In order to solve the above problems, the present invention provides a refrigeration system including:

compressor, condenser, freezing evaporimeter and cold-stored evaporimeter and first pipeline and second pipeline, freezing evaporimeter sets up on the first pipeline, cold-stored evaporimeter sets up on the second pipeline, the compressor has low pressure induction port and middling pressure induction port, the one end of first pipeline with condenser intercommunication, the other end with low pressure induction port intercommunication, the one end of second pipeline also with condenser intercommunication, the other end with middling pressure induction port intercommunication, just lie in on the first pipeline lie in freezing evaporimeter still is provided with first throttling arrangement along the upstream position that the refrigerant flows, lie in on the second pipeline the upstream position that the refrigerant flows along the cold-stored evaporimeter still is provided with second throttling arrangement.

Preferably, the first pipeline is communicated with the second pipeline and then communicated with the condenser, and a first proportional regulating three-way valve is arranged at a position where the first pipeline is communicated with the second pipeline, and the first proportional regulating three-way valve can regulate the flow of the refrigerant entering the first pipeline and regulate the flow of the refrigerant flowing into the second pipeline.

Preferably, a reservoir and/or a dry filter is/are further provided on a pipeline between the condenser and the first proportional regulating three-way valve.

Preferably, the refrigeration system further comprises a third pipeline, one end of the third pipeline is communicated to the first pipeline and is located between the freezing evaporator and the first throttling device, and the other end of the third pipeline passes through the refrigeration evaporator and then is communicated to the first pipeline and is located between the freezing evaporator and the compressor, so that the refrigerant in the third pipeline exchanges heat in the refrigeration evaporator.

Preferably, a second proportional three-way valve is further provided on the third line and the first line at a position communicating between the refrigeration evaporator and the first throttling device.

Preferably, the first throttling device is an electronic expansion valve; and/or the second throttling device is an electronic expansion valve; and/or when the device further comprises a first proportional regulating three-way valve, the first proportional regulating three-way valve is an electric proportional regulating three-way valve; and/or when a second proportional control three-way valve is further included, the second proportional control three-way valve is an electric proportional control three-way valve.

The present invention also provides a control method applicable to the refrigeration system of any one of the above, which, when including the first proportional regulating three-way valve, includes:

a detection step, which is used for detecting the pressure of a medium-pressure air suction port of the compressor, detecting the refrigerant pressure of an outlet of the refrigeration evaporator on a second pipeline and detecting the opening degree of a second throttling device;

judging whether the pressure of a refrigerant at the outlet of the refrigeration evaporator is smaller than the pressure of the medium-pressure air suction port or not, and simultaneously judging the relationship between the opening degree of the second throttling device and the maximum opening degree of the second throttling device;

a control step of controlling the opening of the first proportional control three-way valve to increase the flow rate of the refrigerant flowing into the second line when the refrigerant pressure at the outlet of the refrigeration evaporator is smaller than the pressure at the medium-pressure suction port and the opening of the second throttle device is equal to the maximum opening; when the pressure of the refrigerant at the outlet of the refrigeration evaporator is larger than the pressure of the medium-pressure suction port and the opening degree of the second throttling device is smaller than the maximum opening degree, controlling and adjusting the opening degree of the first proportional adjustment three-way valve to reduce the flow rate of the refrigerant flowing into the second pipeline; when the pressure of the refrigerant at the outlet of the refrigeration evaporator is equal to the pressure of the medium-pressure suction port, the opening degree of the first proportional regulating three-way valve is controlled and regulated to be unchanged.

Preferably, the controlling step is further configured to control the opening degree of the second throttling device to increase when the refrigerant pressure at the outlet of the refrigeration evaporator is less than the pressure of the medium-pressure suction port and the opening degree of the second throttling device is less than the maximum opening degree; and/or the control step is also used for controlling and regulating the opening degree of the second throttling device to be reduced when the pressure of the refrigerant at the outlet of the refrigeration evaporator is greater than the pressure of the medium-pressure suction port and when the opening degree of the second throttling device is equal to the maximum opening degree.

Preferably, when the second proportional three-way valve is included, the control method further includes:

the detection step is also used for detecting the actual working condition temperature of the refrigeration evaporator and detecting the opening degree of the second throttling device;

the judging step is also used for judging the size relationship between the actual working condition temperature of the refrigeration evaporator and a preset temperature value and simultaneously judging the relationship between the opening size of the second throttling device and the maximum opening size of the second throttling device;

a control step of controlling and adjusting the opening of the second proportional control three-way valve to increase the flow rate of the refrigerant flowing into the third pipeline when the actual working condition temperature of the refrigeration evaporator is greater than a preset temperature value and the opening of the second throttling device is equal to a maximum opening; when the actual working condition temperature of the refrigeration evaporator is lower than a preset temperature value, controlling and adjusting the opening of the second proportional control three-way valve to increase and decrease the flow of the refrigerant flowing into the third pipeline; and when the actual working condition temperature of the refrigeration evaporator is equal to the preset temperature value, controlling and adjusting the opening of the second proportional control three-way valve to be unchanged.

Preferably, the control step is further configured to, when the actual operating condition temperature of the refrigeration evaporator is less than a preset temperature value, control and adjust the opening of the second proportional control three-way valve to be reduced to 0, so that the flow rate of the refrigerant flowing into the third pipeline is 0; and/or the presence of a gas in the gas,

the control step is also used for controlling and adjusting the opening degree of the second proportional control three-way valve to be reduced to 0 and controlling the opening degree of the second throttling device to be reduced when the actual working condition temperature of the refrigeration evaporator is smaller than a preset temperature value; and/or the presence of a gas in the gas,

and the control step is also used for controlling and adjusting the opening degree of the second throttling device to increase when the actual working condition temperature of the refrigeration evaporator is greater than a preset temperature value and the opening degree of the second throttling device is smaller than the maximum opening degree.

The refrigeration system and the control method thereof provided by the invention have the following beneficial effects:

1. the invention sets two different pipelines, each pipeline is respectively provided with a freezing evaporator and a refrigerating evaporator, the compressor is set to be in a structural form with two compression stages (such as two cylinders connected in series), one end of the freezing evaporator is communicated with the condenser, the other end of the freezing evaporator is communicated with the low-pressure air suction port, one end of the refrigerating evaporator is communicated with the condenser, the other end of the refrigerating evaporator is communicated with the medium-pressure air suction port, so that the refrigerating refrigeration and the freezing with two different evaporation temperatures can be simultaneously realized in the same refrigerating system (namely, a refrigerating circulation loop driven by a compressor), and compared with the structural forms of the refrigerating evaporator and the freezing evaporator, the freezing evaporator and the refrigerating evaporator of the invention respectively exchange heat with a refrigerant from the condenser, and the flow is respectively regulated by the first throttling device and the second throttling device, so that the freezing evaporator and the refrigerating evaporator can both carry out phase-change evaporation heat absorption, the suction superheat degree of the compressor after the evaporation is finished is greatly reduced, the exhaust temperature is reduced, the power consumption of the compressor is reduced, and meanwhile, the refrigeration capacity is greatly improved due to the heat exchange in a latent heat state, so that the refrigeration capacity for refrigeration can be effectively met;

2. the invention also can adjust the flow of the refrigerant which respectively enters the first pipeline to exchange heat with the freezing evaporator and the flow of the refrigerant which enters the second pipeline to exchange heat with the refrigerating evaporator by arranging the first proportional adjustment three-way valve, so as to be able to adjust the first proportional three-way flow valve according to the refrigeration parameters of the refrigeration evaporator, to adjust the distribution of the refrigerant flow in the first and second lines, so as to adapt to the control of the refrigeration evaporator and the freezing evaporator under different working conditions, preferably to adjust according to the actual working condition (the relation between the outlet pressure and the pressure of the medium-pressure air suction port) of the refrigeration evaporator, the refrigerating evaporator is effectively ensured to have enough refrigerant flow to achieve enough pressure of medium-pressure air suction of the compressor, the refrigerating evaporator is ensured to effectively and reliably absorb heat in the evaporation process, and the medium-pressure air suction process is ensured to be effectively and reliably carried out;

3. the third pipeline is arranged, so that the refrigerant in the first pipeline is effectively utilized to bypass to the refrigerating evaporator, the refrigerating capacity of the refrigerating evaporator is supplemented, the refrigerating capacity of the refrigerating evaporator is improved, the situation that the refrigerating temperature in the refrigerating chamber is insufficient due to the fact that the refrigerant in the second pipeline is insufficient in the refrigerating evaporator is prevented, the normal and reliable operation of the refrigerating evaporator is guaranteed, and the refrigerating work of the refrigerating chamber is guaranteed to be normally and effectively carried out; and through the setting of second proportion regulation three-way valve, can be further to be used for carrying out the refrigerant flow that supplements to cold-stored evaporimeter in this third pipeline according to actual need or adjust according to operating condition, preferably adjust according to operating condition (evaporating temperature's size), can effectively guarantee to have sufficient refrigerant flow in the cold-stored evaporimeter, in order to reach sufficient evaporating temperature, realize required cold-stored refrigeration volume.

Drawings

Fig. 1 is a system configuration diagram of a refrigeration system of the present invention.

The reference numerals are represented as:

1. a compressor; 11. a low-pressure air suction port; 12. a medium pressure suction port; 2. a condenser; 3. a refrigeration evaporator; 4. a refrigerated evaporator; 51. a first throttling device; 52. a second throttling device; 61. a first proportional regulating three-way valve; 62. a second proportional regulating three-way valve; 7. a reservoir; 8. drying the filter; 9. a gas-liquid separator; 101. a first pipeline; 102. a second pipeline; 103. a third pipeline.

Detailed Description

As shown in fig. 1, the present invention provides a refrigeration system comprising:

a compressor 1, a condenser 2, a freezing evaporator 3 and a refrigerating evaporator 4 and a first pipe 101 and a second pipe 102, the freezing evaporator 3 is provided on the first pipe 101, the refrigerating evaporator 4 is provided on the second pipe 102, the compressor 1 has a low pressure suction port 11 and a medium pressure suction port 12 (the suction pressure of the medium pressure suction port is greater than that of the low pressure suction port), one end of the first pipe 101 communicates with the condenser 2, the other end communicates with the low pressure suction port 11, the second line 102 also communicates at one end with the condenser 2 and at the other end with the medium-pressure suction port 12, and a first throttle device 51 is further provided on the first pipe 101 at a position upstream of the freezing evaporator 3 in the flow of the refrigerant, a second throttle device 52 is also provided in the second line 102 at a position upstream of the refrigerating evaporator 4 in the refrigerant flow direction.

The invention sets two different pipelines, each pipeline is respectively provided with a freezing evaporator and a refrigerating evaporator, the compressor is set to be in a structural form with two compression stages (such as two cylinders connected in series), one end of the freezing evaporator is communicated with the condenser, the other end of the freezing evaporator is communicated with the low-pressure air suction port, one end of the refrigerating evaporator is communicated with the condenser, the other end of the refrigerating evaporator is communicated with the medium-pressure air suction port, so that the refrigerating refrigeration and the freezing with two different evaporation temperatures can be simultaneously realized in the same refrigerating system (namely, a refrigerating circulation loop driven by a compressor), and compared with the structural forms of the refrigerating evaporator and the freezing evaporator, the freezing evaporator and the refrigerating evaporator of the invention respectively exchange heat with a refrigerant from the condenser, and the flow is respectively regulated by the first throttling device and the second throttling device, so that the freezing evaporator and the refrigerating evaporator can both carry out phase-change evaporation heat absorption, the suction superheat degree of the compressor after the evaporation is finished is greatly reduced, the exhaust temperature is reduced, the power consumption of the compressor is reduced, and meanwhile, due to the fact that the compressor is in a latent heat state for heat exchange, the refrigeration capacity of the compressor is greatly improved, and the refrigeration capacity for refrigeration can be effectively met.

The refrigerating system of the invention comprises components such as a two-stage compressor, a condenser, a liquid storage device, a drying filter, a first proportion adjusting three-way valve 61, a first throttling device 51, a second proportion adjusting three-way valve 62, an evaporator for freezing, a second throttling device 52, an evaporator for refrigerating, a gas-liquid separator and the like. The system can realize the dual-purpose functions of freezing and refrigerating at the same time, meets the requirement of a user on dual purposes, and ensures that the freezing and refrigerating performance of the unit is better by matching with the set pipeline component combination.

The operation and control of the refrigeration system of the invention use:

1. operation of the system

The high-temperature and high-pressure refrigerant gas discharged from the two-stage compressor enters a condenser for heat exchange and cooling, flows through a drying filter through a liquid storage device, flows to a first proportional control three-way valve 61 for regulation and distribution to two pipelines, flows to the refrigerant of the second pipeline 102, is throttled and depressurized through a second throttling device 52 (preferably an electronic expansion valve) to reach the set refrigerant pressure, enters a refrigeration evaporator for heat exchange and evaporation, and flows back to a medium-pressure air suction port of the two-stage compressor; the refrigerant flowing to the first pipeline 101 is throttled and depressurized by the first throttling device 51 (preferably an electronic expansion valve) to reach a set refrigerant pressure value, then flows through the second proportional control three-way valve 62 to be adjusted and distributed into two paths, the refrigerant flowing out of the first pipeline 101 of the second proportional control three-way valve 62 flows into the freezing evaporator to be subjected to heat exchange and evaporation, the refrigerant flowing out of the third pipeline 103 of the second proportional control three-way valve 62 flows into a specific pipeline of the refrigeration evaporator 4 to be subjected to heat exchange and evaporation, the refrigerant flowing out of the refrigeration evaporator and the refrigerant flowing out of the freezing evaporator are converged and then flow into the gas-liquid separator, the refrigerant gas flowing out of the gas-liquid separator flows back to the low-pressure suction port of the two-stage compressor, and the whole system is operated in a reciprocating cycle mode.

Preferably, the first pipeline 101 communicates with the second pipeline 102 and then communicates with the condenser 2, and a first proportional three-way valve 61 is provided at a position where the first pipeline 101 communicates with the second pipeline 102, and the first proportional three-way valve 61 is capable of adjusting the flow of the refrigerant into the first pipeline 101 and adjusting the flow of the refrigerant into the second pipeline 102. The invention also provides a three-way valve for adjusting the first ratio, which can adjust the flow of the refrigerant entering the first pipeline for heat exchange with the freezing evaporator and the flow of the refrigerant entering the second pipeline for heat exchange with the refrigerating evaporator respectively by arranging a three-way valve for adjusting the first ratio, which can adjust the flow valve of the three-way valve according to the refrigeration parameters of the refrigerating evaporator, so as to adjust the distribution of the flow of the refrigerant in the first pipeline and the second pipeline, so as to adapt to the control of the refrigerating evaporator and the freezing evaporator under different working conditions, preferably adjust according to the actual working conditions (the relation between the outlet pressure and the pressure of the medium-pressure air suction port) of the refrigerating evaporator, so as to effectively ensure that the refrigerating evaporator has enough refrigerant flow to achieve the enough pressure of the medium-pressure air suction of the compressor, ensure that the evaporation and heat absorption of the refrigerating evaporator are effectively and reliably.

Preferably, a reservoir 7 and/or a dry filter 8 are/is further provided on a line between the condenser 2 and the first proportional regulating three-way valve 61. According to the invention, the liquid storage device and the drying filter are arranged to dehydrate the gas-liquid mixed refrigerant, and both the liquid storage device and the drying filter can be used for absorbing liquid refrigerant or other impurities.

Preferably, the refrigeration system further comprises a third pipeline 103, one end of the third pipeline 103 is connected to the first pipeline 101 and located between the freezing evaporator 3 and the first throttling device 51, and the other end of the third pipeline 103 passes through the refrigeration evaporator 4 and then is connected to the first pipeline 101 and located between the freezing evaporator 3 and the compressor 1, so that the refrigerant in the third pipeline 103 exchanges heat in the refrigeration evaporator 4. The third pipeline is arranged, so that the refrigerant in the first pipeline is effectively utilized to bypass to the refrigerating evaporator, the refrigerating capacity of the refrigerating evaporator is supplemented, the refrigerating capacity of the refrigerating evaporator is improved, the situation that the refrigerating temperature in the refrigerating chamber is insufficient due to the fact that the refrigerant in the second pipeline is insufficient in the refrigerating evaporator is prevented, the normal and reliable operation of the refrigerating evaporator is guaranteed, and the refrigerating work of the refrigerating chamber is guaranteed to be normally and effectively carried out.

Preferably, a second proportional three-way valve 62 is also provided on the third line 103 and the first line 101 at a position communicating between the refrigeration evaporator 3 and the first throttling means 51. Through the setting of second proportion regulation three-way valve, can be further to be used for carrying out the refrigerant flow that supplements to cold-stored evaporimeter in this third pipeline according to actual need or adjust according to operating condition, preferably adjust according to operating condition (evaporating temperature's size), can effectively guarantee to have sufficient refrigerant flow in the cold-stored evaporimeter, in order to reach sufficient evaporating temperature, realize required cold-stored refrigeration volume.

Preferably, the first throttling means 51 is an electronic expansion valve; and/or, the second throttling device 52 is an electronic expansion valve; and/or, when a first proportional three-way valve 61 is further included, the first proportional three-way valve 61 is an electric proportional three-way valve; and/or, when a second proportional three-way valve 62 is further included, the second proportional three-way valve 62 is an electric proportional three-way valve. The first throttling device and the second throttling device are both preferably electronic expansion valves, so that intelligent control is realized; the electric proportional control three-way valve can realize the function of accurately and intelligently controlling the flow of the first branch.

The present invention also provides a control method of the refrigeration system recited in any one of the foregoing items, which, when including the first proportional regulating three-way valve 61, includes:

a detection step, which is used for detecting the pressure of a medium-pressure air suction port of the compressor, detecting the refrigerant pressure of an outlet of the refrigeration evaporator on a second pipeline and detecting the opening degree of a second throttling device;

judging whether the pressure of a refrigerant at the outlet of the refrigeration evaporator is smaller than the pressure of the medium-pressure air suction port or not, and simultaneously judging the relationship between the opening degree of the second throttling device and the maximum opening degree of the second throttling device;

a control step of controlling the opening degree of the first proportional control three-way valve 61 to increase the flow rate of the refrigerant flowing into the second pipe line 102 when the refrigerant pressure at the outlet of the refrigeration evaporator is smaller than the pressure at the medium-pressure suction port and the opening degree of the second throttle device is equal to the maximum opening degree; when the refrigerant pressure at the outlet of the refrigeration evaporator is greater than the pressure of the medium-pressure suction port and when the opening degree of the second throttling means is less than the maximum opening degree, controlling and adjusting the opening degree of the first proportional adjustment three-way valve 61 so that the flow rate of the refrigerant flowing into the second pipeline 102 is reduced; when the refrigerant pressure at the outlet of the refrigeration evaporator is equal to the pressure at the medium-pressure suction port, the control adjusts the opening degree of the first proportional regulating three-way valve 61 to be constant.

The first proportional control three-way valve is a control means for controlling and adjusting according to the relationship between the outlet pressure of the refrigeration evaporator and the medium-pressure suction pressure, when the refrigerant pressure at the outlet of the refrigeration evaporator is smaller than the pressure of the medium-pressure suction port, the refrigerant flow at the outlet of the refrigeration evaporator is smaller, and the refrigerant flow does not reach enough pressure, so that the refrigerant flow in the second pipeline needs to be increased, and the opening degree of the second throttling device is the maximum opening degree, so that the refrigerant flow in the second pipeline can be increased only by adjusting the first proportional control three-way valve, so that the outlet pressure of the refrigeration evaporator reaches the medium-pressure suction pressure, and normal and effective medium-pressure suction is performed; when the pressure of the refrigerant at the outlet of the refrigeration evaporator is greater than the pressure of the medium-pressure air suction port, the flow of the refrigerant at the outlet of the refrigeration evaporator is sufficient, and the condition that the medium-pressure air suction port sucks air is met, at the moment, the flow of the refrigerant in the second pipeline is reduced, and at the moment, if the opening degree of the second throttling device is smaller than the maximum opening degree, the pipeline is likely to be blocked and the like, so that the conditions that the flow of the refrigerant entering the second pipeline is effectively reduced by adjusting the first proportional adjusting three-way valve, the pressure at the outlet of the refrigeration evaporator is reduced, and the effective medium-pressure air suction effect is achieved; when the refrigerant pressure at the outlet of the refrigeration evaporator is equal to the pressure at the medium-pressure suction port, the refrigerant pressure is just suitable for medium-pressure suction, so the opening degree of the first proportional control three-way valve 61 is controlled and adjusted to be unchanged.

Preferably, the controlling step is further configured to control the opening degree of the second throttling device to increase when the refrigerant pressure at the outlet of the refrigeration evaporator is less than the pressure of the medium-pressure suction port and the opening degree of the second throttling device is less than the maximum opening degree; and/or, the controlling step is further used for controlling and adjusting the opening degree of the second throttling device 52 to be reduced when the pressure of the refrigerant at the outlet of the refrigeration evaporator is larger than the pressure of the medium-pressure suction port and when the opening degree of the second throttling device is equal to the maximum opening degree.

This is a further preferable control form of the present invention for adjusting the opening of the first proportional three-way valve according to the outlet pressure of the refrigeration evaporator and the medium-pressure suction pressure, i.e. when the refrigerant pressure at the outlet of the refrigeration evaporator is smaller than the pressure at the medium-pressure suction port, the pressure of the second pipeline needs to be increased, but when the opening of the second throttling device is smaller than the maximum opening, the opening of the second throttling device is preferably increased first, so as to increase the refrigerant flow into the refrigeration evaporator as fast as possible and increase the outlet pressure; when the refrigerant pressure at the outlet of the refrigeration evaporator is higher than the pressure at the medium-pressure suction port, the refrigerant flow rate of the second pipeline needs to be reduced, but when the opening degree of the second throttling device is equal to the maximum opening degree, the opening degree of the second throttling device should be preferentially reduced, so that the refrigerant flow rate entering the refrigeration evaporator is reduced through the opening degree control of the second throttling device to reduce the outlet pressure.

2. Control of the first proportional three-way valve 61

The first proportional control three-way valve 61 is used to appropriately distribute the refrigerant flowing to the freezing evaporator and the refrigerating evaporator, thereby preventing the refrigerant flowing through the freezing evaporator or the refrigerating evaporator from being very small and failing to satisfy the required cooling capacity.

(1) When the refrigerant pressure at the outlet of the evaporator for cold storage is less than the set medium-pressure suction port refrigerant pressure and the opening degree of the second throttling device 52 reaches the maximum state, the first proportional control three-way valve 61 adjusts and increases the amount of the refrigerant flowing to the second pipeline 102, so that the refrigerant pressure at the outlet of the evaporator for cold storage reaches the set medium-pressure suction port pressure value.

(2) When the refrigerant pressure at the outlet of the refrigeration evaporator is equal to the set medium-pressure suction port refrigerant pressure, the opening degree of the first proportional control three-way valve 61 is kept constant.

(3) When the refrigerant pressure at the outlet of the evaporator for cold storage is greater than the set medium-pressure suction port refrigerant pressure and the opening degree of the second throttling device 52 is small (smaller than the maximum opening degree of the second throttling device 52), the first proportional regulating three-way valve 61 reduces the amount of the refrigerant flowing to the second pipeline 102, so that the refrigerant pressure at the outlet of the evaporator for cold storage is reduced to the set medium-pressure suction port pressure value.

Preferably, when the second proportional three-way valve 62 is included, the control method further includes:

the detection step is also used for detecting the actual working condition temperature of the refrigeration evaporator and detecting the opening degree of the second throttling device;

the judging step is also used for judging the size relationship between the actual working condition temperature of the refrigeration evaporator and a preset temperature value and simultaneously judging the relationship between the opening size of the second throttling device and the maximum opening size of the second throttling device;

a control step of controlling and adjusting the opening of the second proportional control three-way valve 62 to increase the flow rate of the refrigerant flowing into the third pipeline 103 when the actual working condition temperature of the refrigeration evaporator is greater than a preset temperature value and the opening of the second throttling device is equal to a maximum opening; when the actual working condition temperature of the refrigeration evaporator is lower than the preset temperature value, controlling and adjusting the opening degree of the second proportional control three-way valve 62 to increase and decrease the flow rate of the refrigerant flowing into the third pipeline 103; and when the actual working condition temperature of the refrigeration evaporator is equal to the preset temperature value, controlling and adjusting the opening degree of the second proportional control three-way valve 62 to be unchanged.

The second proportional control three-way valve is a control means for controlling and adjusting according to the relation between the evaporation working condition temperature of the refrigeration evaporator and the preset temperature, when the actual working condition temperature of the refrigeration evaporator is higher than the preset temperature value, the flow of the refrigerant entering the refrigeration evaporator for heat exchange is small, so that the effective evaporation heat absorption cannot be completed to reduce the evaporation temperature, the heat exchange flow of the refrigeration evaporator needs to be increased, and the opening degree of the second throttling device is the maximum opening degree at the moment, so that the flow of the refrigerant in the third pipeline can be increased only by adjusting the second proportional control three-way valve and supplementing the refrigerant, and the evaporation temperature of the refrigeration evaporator reaches the preset temperature; when the actual working condition temperature of the refrigeration evaporator is lower than the preset temperature value, the flow of the refrigerant entering the refrigeration evaporator for heat exchange is enough, effective evaporation and heat absorption are carried out, and the flow of the refrigerant in the third pipeline is reduced at the moment, so that the flow of the refrigerant entering the third pipeline is effectively reduced by adjusting the second proportional adjusting three-way valve, and the flow of the refrigerant entering the refrigeration evaporator is reduced and supplemented, so that the evaporation temperature of the refrigeration evaporator reaches the preset temperature; when the actual working condition temperature of the refrigeration evaporator is equal to the preset temperature value, it is indicated that the working condition of the refrigerant temperature is identical to the preset temperature, and the target working condition is reached, so that the opening degree of the second proportional control three-way valve 62 is controlled and adjusted to be unchanged.

Preferably, the control step is further configured to control and adjust the opening degree of the second proportional control three-way valve 62 to be reduced to 0 when the actual working condition temperature of the refrigeration evaporator is less than the preset temperature value, so that the flow rate of the refrigerant flowing into the third pipeline 103 is 0; and/or the presence of a gas in the gas,

the control step is also used for controlling and adjusting the opening degree of the second proportional control three-way valve 62 to be reduced to 0 and controlling the opening degree of the second throttling device to be reduced when the actual working condition temperature of the refrigeration evaporator is smaller than a preset temperature value; and/or the presence of a gas in the gas,

and the control step is also used for controlling and adjusting the opening of the second throttling device 52 to increase when the actual working condition temperature of the refrigeration evaporator is greater than a preset temperature value and the opening of the second throttling device is smaller than the maximum opening.

The opening of the second proportional regulating three-way valve is regulated according to the temperature of the evaporation working condition of the refrigeration evaporator and the preset temperature, namely when the actual working condition temperature of the refrigeration evaporator is lower than the preset temperature, the supplementary refrigerant flow of the third pipeline needs to be reduced, and the supplementary refrigerant flow can be further reduced to 0 so as to rapidly reduce the temperature of the evaporation working condition of the refrigeration evaporator; when the actual working condition temperature of the refrigeration evaporator is lower than the preset temperature value, the supplementary refrigerant flow of the third pipeline needs to be reduced, and the flow of the refrigerant in the refrigeration evaporator can be further reduced by reducing the refrigerant flow in the second pipeline, so that the evaporation working condition temperature of the refrigeration evaporator is further and quickly reduced; when the actual working condition temperature of the refrigeration evaporator is larger than the preset temperature value, the flow of the supplementary refrigerant of the third pipeline is increased, but the purpose of reducing the temperature of the evaporation working condition can be achieved by increasing the flow of the refrigerant in the second pipeline and increasing the heat exchange of the refrigeration evaporator when the opening degree of the second throttling device is smaller than the maximum opening degree.

3. Control of the second proportional three-way valve 62

The second proportional control three-way valve 62 is used for dividing a part of refrigerant to supplement the capacity of the refrigeration evaporator, so as to prevent the refrigerant capacity of the refrigeration evaporator from being incapable of meeting the use requirement.

(1) When the actual operating temperature of the refrigeration evaporator is greater than the set value while the second throttling device 52 has reached the optimum operating state (preferably, the maximum opening degree is reached), the second proportional regulating three-way valve 62 regulates to increase the refrigerant flow rate in the third pipeline 103 so that the actual operating temperature of the refrigeration evaporator is equal to the set value.

(2) When the actual operating temperature of the refrigeration evaporator is equal to the set value and the second throttle device 52 is in the optimum operating state (preferably, the maximum opening degree is reached), the opening degree of the second proportional three-way valve 62 is kept constant.

(3) When the actual working condition temperature of the refrigeration evaporator is less than the set value, the opening degree of the second proportional control three-way valve 62 is adjusted, so that no refrigerant flows through the third pipeline 103.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention. The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.