CN103954062B - A kind of mixture throttling refrigerating machine operating mode concentration control system and method thereof - Google Patents

Abstract

The invention discloses a mixed working medium throttling refrigerator operating condition concentration control system and a method thereof, which include a compressor unit, a condensing cooler unit, a regenerative heat exchanger unit, a throttling unit, an evaporator unit, and a controllable passage Working fluid concentration and flow adjustment unit, control unit. Its input parameters are compressor suction pressure and/or discharge pressure value of the refrigerator system, inlet temperature value of recuperator heat exchanger, outlet temperature value of recuperator heat exchanger, inlet temperature value of throttling unit, outlet temperature value of throttling unit The temperature value, the outlet temperature value of the evaporator, and the output parameters are instructions for controlling the corresponding actions of the execution unit. Corresponding to the different operating conditions and capacity adjustment requirements of the mixed working medium throttling refrigerator system, according to the comparison between the preset value and the input parameters, the circulating concentration of the working medium in the controllable channel and the flow adjustment unit are used to control the circulating concentration of the working medium in the refrigeration system. Control and adjust to make it adapt to the operating requirements of different working conditions and maintain high operating efficiency.

Description

A mixed working fluid throttling refrigerator working condition concentration control system and method thereof

technical field

The invention relates to the subject field of engineering thermophysics and energy utilization, in particular to a concentration control system and a method for working condition concentration of a mixed working medium throttling refrigerator.

Background technique

Using traditional vapor compression refrigeration technology, the minimum effective refrigeration temperature that can be achieved by a single-stage cycle is around -40°C. If you want to achieve a lower refrigeration temperature, you need to use multi-stage compression or multi-stage cascade cycle. In the existing technology, two-stage compression can achieve a refrigeration temperature of about -60°C, and a two-stage cascade cycle can achieve a refrigeration temperature of about -80°C, but to achieve a refrigeration temperature of -100°C or even lower, it is necessary to Take more than three levels of cascade loops. Therefore, as the demand temperature decreases, the refrigeration system of vapor compression refrigeration technology becomes more complex, less reliable, and more difficult to adjust. After the 1980s, important progress has been made in multivariate mixed refrigerant throttling refrigeration technology. This technology enables the throttling refrigeration to reach -100℃～- The low temperature of 200°C, therefore, this technology can replace the cascade cycle in the temperature range below -100°C, and it has broad application prospects.

However, due to the characteristics of the mixed working medium used in the mixed working medium throttling refrigeration technology, if the corresponding technical means are not used to control it, there will be some defects as follows: (1) The multi-component mixed working medium cryogenic refrigeration system, due to the use of Strong non-azeotropic working fluid, the working fluid is basically exothermic in the gas phase in the condenser, and the outlet of the condenser has a certain dryness and will not be overcooled. The high pressure of the system operation is basically not controlled by the ambient temperature, but is determined by the working fluid charge and system structural parameters. In the initial stage of the refrigeration system start-up process, the entire system is basically at a relatively high temperature, and most of the charging fluid is still in the gas phase state, so the exhaust pressure will be too high; (2) When the mixed fluid refrigeration system enters After normal refrigeration working conditions, because most of the working fluid with higher boiling point has been liquefied, the system pressure will drop sharply at this time, and the cooling capacity will decrease sharply; Slip phenomenon. In the process of cooling the multi-component mixed working fluid refrigeration system from the start-up condition to the lowest temperature, due to the continuous drop of the system temperature, the working fluid is continuously liquefied. The working medium is liquefied first, and the gas-liquid two-phase flow rate has the characteristics of velocity slip, that is, the flow rate of the liquid-phase working medium is lower than that of the gas-phase working medium, and the liquid-phase accumulation of the working medium will occur at this time. Due to the existence of the phenomenon of liquid phase accumulation in multi-component mixed refrigerant refrigeration systems, the actual circulating concentration of refrigerants in the refrigeration system will deviate from the actual charging concentration, that is, the concentration of refrigerants will slip. Due to this shortcoming, on the one hand, the actual circulating concentration of the mixed working fluid is affected by factors such as the actual operating conditions and the size of the system. That is to say, it is difficult to determine the optimal filling volume and concentration of the mixed working fluid, and it is even more difficult to determine the optimal filling volume and filling concentration for refrigeration systems using ternary or more mixed working fluids. Different types of systems require The final filling amount and concentration can only be obtained through a large number of test fillings, and the production cost is high. On the other hand, even for the same system, under different working conditions in the temperature zone, the refrigeration system needs different concentrations to achieve the best efficiency in the temperature zone. The efficiency of the system drops sharply, and even the temperature cannot drop.

In response to the first two defects, Chinese invention patent ZL200510042730.9 reports a low-temperature throttling refrigeration system with a mixed working medium with a switchable gas storehouse. The air storage is used to adjust the quality of the system's participating cycle work to control the high and low pressure and the working conditions of the system. Although this method can control the high and low pressure within a reasonable range, the concentration of the working medium that actually participates in the refrigeration cycle will change uncontrollably due to the gas entering and exiting the gas storage, which will cause a serious decline in the refrigeration performance of the refrigeration system;

Chinese invention patent ZL201110061458.4 reports a cryogenic mixed working fluid throttling refrigeration system capacity, working condition adjustment and control method. Its core idea is to prevent the exhaust pressure of the compressor from being too high in the start-up condition by controlling the high-pressure gas to enter a controllable passage stabilizing tank, and to adjust the low pressure by controlling the gas in and out of the controllable passage stabilizing tank, so that the low pressure is stable under low temperature conditions. In addition, the controllable passage stabilizing tank is bypassed through the pipeline to reduce the refrigerant circulation of the refrigeration system under the start-up condition and the rapid cooling condition. The refrigerant participates in the refrigeration cycle to increase the flow rate of the refrigeration system, so that the power is maintained at a high level, that is, the capacity and working conditions of the refrigeration system can be adjusted by controlling the entry and exit of the refrigerant in the controllable path stabilization tank. The disadvantage is that the circulating concentration of the working medium in the refrigeration system will change to a certain extent when switching whether the gas in the gas storage tank participates in the cycle and adjusting the high and low pressure, which will cause the system to deviate from the optimal circulating concentration of the working medium under certain working conditions. , leading to a decrease in efficiency, especially in the rapid cooling process. At the beginning of the process, the evaporation temperature is high. Under high temperature conditions, the circulating concentration of the working fluid of the system requires a large proportion of heavy components to achieve a better circulating concentration.

For the third shortcoming, there is no report on related methods or means to control or utilize it to develop in a beneficial direction.

In fact, according to the requirements of the refrigeration system for the optimal circulating concentration of working fluid in different temperature regions, if the circulating concentration of working medium in high temperature conditions can be adjusted by means of control, it will make the circulating concentration of working medium closer to the optimal Concentration, improve efficiency, increase cooling capacity, further shorten the cooling time in the high temperature zone; similarly, in the process of rapid cooling, when the temperature drops to the working condition of the medium temperature zone, the optimal working fluid concentration of the system is no longer The concentration of the working condition in the high temperature area requires that the proportion of heavy components in the circulating concentration of the working fluid at this time should be reduced to make the heat transfer curve of the regenerator match better. Therefore, at this time, it is also necessary to adjust the refrigeration system through control means according to the working condition The circulating concentration of working fluid makes the circulating concentration of working fluid more suitable for the working conditions in this temperature zone. In this way, the efficiency of the system is ensured by adjusting the appropriate concentration. Generally speaking, the power of the system does not change much after adjusting the concentration, but the efficiency can be improved; instead of adjusting the concentration, just increasing the flow to increase the power may be due to changes in the concentration. , the refrigeration efficiency cannot be improved. Obviously, this method is not effective compared with adjusting the concentration and is not energy-saving. Therefore, in the rapid cooling stage, the cooling speed in different temperature zones can be greatly accelerated by adjusting the circulating concentration of the working fluid closer to the optimal concentration, and the entire cooling time will be greatly shortened.

Therefore, whether it is to cool down the refrigeration system or enable the refrigeration system to operate at a better concentration of working fluid in each temperature zone, it is necessary to take certain technical means to control the circulating concentration of working fluid in the system.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings and deficiencies of the above-mentioned prior art, and provide a mixed working medium throttling refrigerator operating condition concentration control system and its method, so as to realize rapid cooling of the refrigeration system and maintain high efficiency and stable operation.

The present invention realizes through following technical scheme:

A mixed working medium throttling refrigerator operating condition concentration control system, including a compressor unit 1, a condensing cooler unit 2, a heat recovery heat exchanger unit 3, a throttling unit 4, an evaporator unit 5, and a controllable channel working medium Circulation concentration and flow adjustment unit 6, control unit 7;

The controllable passage working medium circulation concentration and flow adjustment unit (6) includes: a controllable main circuit valve V1, a controllable bypass tank inlet valve V2, a controllable working medium outlet valve V3, a tank outlet one-way valve V4 and Controllable low-pressure tank outlet valve V5;

It is connected by pipelines, and the connection method is: the inlet port of the controllable main circuit valve V1 is connected to the first outlet of the three-way fitting A, and the second outlet of the three-way fitting A is connected to the controllable bypass tank inlet valve Import port of V2;

The outlet end of the controllable bypass tank inlet valve V2 communicates with the high-pressure inlet end of the gas-liquid separation tank S;

The outlet end of the controllable main circuit valve V1 is connected to the first inlet of the three-way pipe fitting B, and the second inlet of the three-way pipe fitting B is connected to the outlet end of the tank outlet check valve V4;

The inlet end of the tank outlet check valve V4 is connected to the first outlet of the three-way pipe fitting C, and the inlet of the three-way pipe fitting C communicates with the top gas phase outlet end of the gas-liquid separation tank S;

The inlet end of the controllable working medium outlet valve V3 is connected to the outlet end at the bottom of the liquid storage tank S;

The outlet end of the controllable working medium outlet valve V3 communicates with the inlet of the low-pressure pipeline of the recuperation heat exchanger unit 3;

The inlet end of the controllable low-pressure tank outlet valve V5 is connected to the second outlet of the three-way pipe fitting C, and the outlet end of the controllable low-pressure tank outlet valve V5 is connected with the low-pressure circuit pipeline of the refrigerator;

The inlet end of the three-way pipe fitting A is connected to the outlet end of the high-pressure refrigerant side of the condensing cooler unit 2;

The outlet end of the three-way pipe fitting B is connected to the inlet end of the high-pressure refrigerant side of the regenerative heat exchanger unit (3);

The inlet end of the low-pressure refrigerant side of the regenerative heat exchanger unit 3 is connected to the outlet end of the evaporator unit 5; the inlet end of the evaporator unit 5 is connected to the outlet end of the throttling unit 4;

The inlet end of the throttling unit 4 is connected to the outlet end of the high-pressure refrigerant side of the regenerative heat exchanger unit 3 .

The controllable main circuit valve V1, the controllable bypass tank inlet valve V2, and the controllable low pressure tank outlet valve V5 are all on-off solenoid valves.

The controllable working medium outlet valve V3 is a valve with electric or manual stepless adjustment of opening.

The above-mentioned control method for the concentration control system of the working condition of the mixed working medium throttling refrigerator includes the following steps:

The control unit 7 receives the suction pressure value of the compressor unit 1, the discharge pressure value of the compressor unit 1, the inlet temperature value of the throttling unit 4, the outlet temperature value of the throttling unit 4, and the inlet temperature value of the throttling unit 4. Difference of outlet temperature value, outlet temperature value of evaporator unit 5, inlet temperature value of regenerator heat exchanger unit 3, outlet temperature value of regenerative heat exchanger unit 3, difference between inlet and outlet temperature values of regenerative heat exchanger unit 3 difference or a combination of any of the above parameters; the control unit 7 outputs the control parameters to instruct the controllable channel working medium circulation concentration and the opening/closing or opening adjustment of each valve part of the flow regulating unit 6:

(1) Start-up working condition process:

The controllable main circuit valve V1 is in the open state, the controllable bypass tank inlet valve V2, the controllable working medium outlet valve V3 and the controllable low pressure outlet valve V5 are all in the closed state; Check whether the engine exhaust pressure parameter reaches the set value, and judge whether to turn to the controlled cooling process;

(2) Process of controlled cooling condition:

2-1) The control unit 7 judges according to the parameter of the input evaporator outlet temperature or compressor discharge pressure and the set value. If the control system is in the high temperature condition of the controlled cooling condition, the adjustment method is as follows: the controllable main The circuit valve V1 is in the open state, the controllable bypass inlet valve V2 and the controllable low pressure outlet valve V5 are in the closed state, and the opening state of the controllable working medium outlet valve V3 is determined by the control unit 7 according to the evaporator outlet temperature or compression The parameters of the engine exhaust pressure are determined, specifically:

a) The temperature difference between the inlet and outlet of the regenerative heat exchanger unit is less than the set value of the inlet and outlet temperature difference, and the opening of the controllable working fluid outlet valve V3 is increased; the temperature difference between the inlet and outlet of the regenerative heat exchanger unit is greater than the set value of the inlet and outlet temperature difference Fixed value, the opening of the controllable working medium outlet valve V3 is adjusted to be small;

b) The temperature difference between the inlet and outlet of the throttling unit 4 is greater than the set value of the inlet and outlet temperature difference, and the opening of the controllable working medium outlet valve V3 is increased; the temperature difference between the inlet and outlet of the throttling unit 4 is smaller than the set value of the inlet and outlet temperature difference, and The opening of V3 of the quality control tank valve is adjusted down.

2-2) The control unit 7 judges according to the parameter comparison of the input evaporator outlet temperature or compressor exhaust pressure. If the control system is in the medium temperature working condition of the controlled cooling condition, the adjustment method is as follows: controllable bypass tank inlet valve V2 is in the open state, the controllable main circuit valve V1 and the controllable low-pressure tank outlet valve V5 are in the closed state, and the opening state of the controllable working fluid outlet valve V3 is determined by the control unit 7 according to the input parameters, specifically:

a) The temperature difference between the inlet and outlet of the regenerative heat exchanger unit is less than the set value of the inlet and outlet temperature difference, and the opening of the controllable working fluid outlet valve V3 is increased; the temperature difference between the inlet and outlet of the regenerative heat exchanger unit is greater than the set value of the inlet and outlet temperature difference Fixed value, the opening of the controllable working medium outlet valve V3 is adjusted to be small;

b) The temperature difference between the inlet and outlet of the throttling unit 4 is greater than the set value of the inlet and outlet temperature difference, and the opening of the controllable working medium outlet valve V3 is increased; the temperature difference between the inlet and outlet of the throttling unit 4 is smaller than the set value of the inlet and outlet temperature difference, and The opening of V3 of the quality control tank valve is adjusted down.

2-3) The control unit 7 judges according to the comparison of input evaporator outlet temperature or compressor exhaust pressure parameters. If the system is in the low-temperature working condition of the controlled cooling condition, the adjustment method is as follows: the controllable main circuit valve V1 is in the open state , the controllable bypass inlet valve V2 is in the closed state; the opening state of the controllable working medium outlet valve V3 and the controllable low pressure outlet valve V5 is determined by the control unit 7 according to the parameters of the evaporator outlet temperature or compressor exhaust pressure decide, specifically:

a) The temperature difference between the inlet and outlet of the regenerative heat exchanger unit is less than the set value of the inlet and outlet temperature difference, and the opening of the controllable working fluid outlet valve V3 is increased; the temperature difference between the inlet and outlet of the regenerative heat exchanger unit is greater than the set value of the inlet and outlet temperature difference Fixed value, the opening of the controllable working medium outlet valve V3 is adjusted to be small;

b) The temperature difference between the inlet and outlet of the throttling unit 4 is greater than the set value of the inlet and outlet temperature difference, and the opening of the controllable working medium outlet valve V3 is increased; the temperature difference between the inlet and outlet of the throttling unit 4 is smaller than the set value of the inlet and outlet temperature difference, and Adjust the opening of V3 of the quality control tank valve;

c) The suction pressure of the compressor drops to the set value of the suction pressure of the compressor, and the controllable low-pressure tank outlet valve V5 opens; the suction pressure of the compressor is higher than the set value of the compressor suction pressure, and the controllable low-pressure tank outlet Valve V5 is closed;

(3) Refrigeration system refrigeration process:

The controllable main circuit valve V1 is in the open state, the controllable bypass tank inlet valve V2 is in the closed state, the controllable working fluid outlet valve V3 and the controllable low pressure tank outlet valve V5 are both in the closed state;

(4) Controlled heating or constant temperature working conditions of the refrigeration system:

The controllable main circuit valve V1 is in the open state, the controllable working medium outlet valve V3 is in the closed state, the opening/closing state of the controllable bypass inlet valve V2 and the controllable low pressure outlet valve V5 is controlled by the control unit 7 according to the requirements. Refrigeration status determines on/off status;

When the compressor suction pressure drops to the set value of the compressor suction pressure, the controllable bypass inlet valve V2 and the controllable low pressure outlet valve V5 are opened at the same time; until the compressor suction pressure is higher than the compressor suction pressure Set value, the controllable bypass tank inlet valve V2 and the controllable low pressure tank outlet valve V5 are closed at the same time;

(5) Uncontrolled heating conditions of the refrigeration system:

The controllable bypass tank inlet valve V2 and the controllable low pressure tank outlet valve V5 are in the open state; the controllable main circuit valve V1 and the controllable working medium outlet valve V3 are in the closed state.

Compared with the prior art, the present invention has the following advantages and effects:

For the mixed working fluid throttling refrigeration system, at the initial start-up stage, due to the high temperature of each part of the system, the working fluid filled in the system is basically in the gas phase, and because the flow area of the throttling element is small, the gas phase working fluid Therefore, when the system is first started, the high pressure is very high, the low pressure is very low, and the compression ratio is too large. The high pressure exceeds the withstand voltage limit of the system hardware, and the compressor motor is overloaded and overheated, resulting in failure to start normally. , and even cause compression to burn. Therefore, the present invention can not only adjust the circulation concentration of the working fluid of the system according to different working conditions so that the system can operate at a better working fluid concentration in different temperature zones, but also can overcome the problems of high starting high pressure and excessive compressor pressure ratio. big case. At the same time, under low temperature conditions, it can automatically adjust the low pressure so that it will not be too low, realize the rapid cooling of the refrigeration system, and maintain high efficiency and stable operation.

Description of drawings

Fig. 1 is the structural block diagram of control system of the present invention;

In the figure: 301 represents the air inlet pressure sensor of the compressor; 302 represents the inlet temperature sensor of the recuperator heat exchanger; 303 represents the outlet temperature sensor of the recuperator heat exchanger; 304 represents the outlet temperature sensor of the evaporator;

Figure 2 is a schematic diagram of the structure of the controllable channel working medium circulation concentration and flow adjustment unit (gas-liquid separation tank with controllable valve opening degree control liquid level function);

Fig. 3 The circulating concentration of the better working medium in a ternary mixed working medium single-stage compression regenerative refrigeration system under different temperature zones.

detailed description

The present invention will be described in further detail below in conjunction with specific embodiments.

Example

as the picture shows. The present invention is a mixed working medium throttling refrigerator operating condition concentration control system, comprising a compressor unit 1, a condensing cooler unit 2, a recuperation heat exchanger unit 3, a throttling unit 4, an evaporator unit 5, and a controllable passage Working fluid concentration and flow adjustment unit 6, control unit 7;

The controllable passage working medium circulation concentration and flow adjustment unit 6 includes: a controllable main circuit valve V1, a controllable bypass tank inlet valve V2, a controllable working medium outlet valve V3, a tank outlet one-way valve V4 and a controllable Low pressure tank valve V5;

It is connected by pipelines, and the connection method is: the inlet port of the controllable main circuit valve V1 is connected to the first outlet of the three-way fitting A, and the second outlet of the three-way fitting A is connected to the controllable bypass tank inlet valve Import port of V2;

The outlet port of the controllable bypass tank inlet valve V2 communicates with the high-pressure inlet port of the gas-liquid separation tank S (with the function of controlling the liquid level through the controllable valve opening);

The outlet end of the controllable main circuit valve V1 is connected to the first inlet of the three-way pipe fitting B, and the second inlet of the three-way pipe fitting B is connected to the outlet end of the tank outlet check valve V4;

The inlet end of the tank outlet check valve V4 is connected to the first outlet of the three-way pipe fitting C, and the inlet of the three-way pipe fitting C communicates with the top gas phase outlet end of the gas-liquid separation tank S;

The inlet end of the controllable working medium outlet valve V3 is connected to the outlet end at the bottom of the liquid storage tank S;

The outlet end of the controllable working medium outlet valve V3 communicates with the inlet of the low-pressure pipeline of the recuperation heat exchanger unit 3;

The inlet end of the controllable low-pressure tank outlet valve V5 is connected to the second outlet of the three-way pipe fitting C, and the outlet end of the controllable low-pressure tank outlet valve V5 is connected with the low-pressure circuit pipeline of the refrigerator;

The inlet end of the three-way pipe fitting A is connected to the outlet end of the high-pressure refrigerant side of the condensing cooler unit 2 (or to the outlet end of the high-pressure refrigerant side of the regenerative heat exchanger unit 3);

The outlet end of the three-way pipe fitting B is connected to the inlet end of the high-pressure refrigerant side of the regenerative heat exchanger unit (3);

The inlet end of the low-pressure refrigerant side of the regenerative heat exchanger unit 3 is connected to the outlet end of the evaporator unit 5; the inlet end of the evaporator unit 5 is connected to the outlet end of the throttling unit 4;

The inlet end of the throttling unit 4 is connected to the outlet end of the high-pressure refrigerant side of the regenerative heat exchanger unit 3 .

The controllable main circuit valve V1, the controllable bypass tank inlet valve V2, and the controllable low pressure tank outlet valve V5 are all on-off solenoid valves.

The controllable working medium outlet valve V3 is a valve with electric or manual stepless adjustment of opening.

The above-mentioned control method for the concentration control system of the working condition of the mixed working medium throttling refrigerator includes the following steps:

The control unit 7 receives the suction pressure value of the compressor unit 1, the discharge pressure value of the compressor unit 1, the inlet temperature value of the throttling unit 4, the outlet temperature value of the throttling unit 4, and the inlet temperature value of the throttling unit 4. Difference of outlet temperature value, outlet temperature value of evaporator unit 5, inlet temperature value of regenerator heat exchanger unit 3, outlet temperature value of regenerative heat exchanger unit 3, difference between inlet and outlet temperature values of regenerative heat exchanger unit 3 difference or a combination of any of the above parameters; the control unit 7 outputs control parameters to instruct the controllable channel working medium circulation concentration and the opening/closing or opening adjustment of each valve part of the flow regulating unit 6 as follows:

(1) Start-up working condition process:

The controllable main circuit valve V1 is in the open state, the controllable bypass tank inlet valve V2, the controllable working medium outlet valve V3 and the controllable low pressure outlet valve V5 are all in the closed state; Whether the compressor exhaust pressure parameter (or the combination of the evaporator outlet temperature and the compressor exhaust pressure parameter) reaches the set value, and judge whether to turn to the controlled cooling process;

(2) Process of controlled cooling condition:

2-1) The control unit 7 compares the input parameters of the evaporator outlet temperature or compressor discharge pressure (or the combination of evaporator outlet temperature and compressor discharge pressure parameters) with the set value to make a judgment. For the high-temperature working condition of the controlled cooling condition, the adjustment method is as follows: the controllable main circuit valve V1 is in the open state, the controllable bypass tank inlet valve V2 and the controllable low-pressure tank outlet valve V5 are in the closed state, and the controllable working fluid outlet valve is in the closed state. The opening state of V3 is determined by the control unit 7 according to the parameters of the outlet temperature of the evaporator or the discharge pressure of the compressor, specifically:

a) The temperature difference between the inlet and outlet of the regenerative heat exchanger unit is less than the set value of the inlet and outlet temperature difference (or the set value of the inlet and outlet temperature difference plus the temperature difference control return difference between the inlet and outlet of the regenerative heat exchanger unit), and the controllable working medium output The opening of the tank valve V3 is increased; the temperature difference between the inlet and outlet of the regenerative heat exchanger unit is greater than the set value of the inlet and outlet temperature difference (or the set value of the inlet and outlet temperature difference plus the return difference controlled by the temperature difference between the inlet and outlet of the regenerative heat exchanger unit) , the opening of the controllable working medium outlet valve V3 is adjusted to be small;

b) The temperature difference between the inlet and outlet of the throttle unit 4 is greater than the set value of the temperature difference between the inlet and outlet (or the set value of the temperature difference between the inlet and outlet plus the return difference controlled by the temperature difference between the inlet and outlet of the throttle unit), and the controllable working medium outlet valve V3 opens The temperature difference between the inlet and outlet of the throttle unit 4 is less than the set value of the temperature difference between the inlet and outlet (or the set value of the temperature difference between the inlet and outlet plus the temperature difference between the inlet and outlet of the throttle unit to control the hysteresis), the controllable working medium outlet valve The opening of V3 is adjusted down.

2-2) The control unit 7 judges according to the comparison of the input parameters of the evaporator outlet temperature or the compressor discharge pressure (or the parameters of the evaporator outlet temperature and the compressor discharge pressure). For medium temperature conditions, the adjustment method is as follows: the controllable bypass tank inlet valve V2 is in the open state, the controllable main circuit valve V1 and the controllable low pressure tank outlet valve V5 are in the closed state, and the opening of the controllable working fluid outlet valve V3 is in the state Determined by the control unit 7 according to the input parameters, specifically:

a) The temperature difference between the inlet and outlet of the regenerative heat exchanger unit is less than the set value of the inlet and outlet temperature difference (or the set value of the inlet and outlet temperature difference plus the temperature difference control return difference between the inlet and outlet of the regenerative heat exchanger unit), and the controllable working medium output The opening of the tank valve V3 is increased; the temperature difference between the inlet and outlet of the regenerative heat exchanger unit is greater than the set value of the inlet and outlet temperature difference (or the set value of the inlet and outlet temperature difference plus the return difference controlled by the temperature difference between the inlet and outlet of the regenerative heat exchanger unit) , the opening of the controllable working medium outlet valve V3 is adjusted to be small;

b) The temperature difference between the inlet and outlet of the throttle unit 4 is greater than the set value of the temperature difference between the inlet and outlet (or the set value of the temperature difference between the inlet and outlet plus the return difference controlled by the temperature difference between the inlet and outlet of the throttle unit), and the controllable working medium outlet valve V3 opens The temperature difference between the inlet and outlet of the throttle unit 4 is less than the set value of the temperature difference between the inlet and outlet (or the set value of the temperature difference between the inlet and outlet plus the temperature difference between the inlet and outlet of the throttle unit to control the hysteresis), the controllable working medium outlet valve The opening of V3 is adjusted down.

2-3) The control unit 7 judges according to the comparison of the input evaporator outlet temperature or the compressor discharge pressure parameter (or the input evaporator outlet temperature and the compressor discharge pressure parameter), if the system is in the low temperature working condition of the controlled cooling condition The adjustment method is as follows: the controllable main circuit valve V1 is in the open state, the controllable bypass tank inlet valve V2 is in the closed state; the opening status of the controllable working medium outlet valve V3 and the controllable low pressure outlet valve V5 The control unit 7 is determined according to the temperature at the outlet of the evaporator or the discharge pressure of the compressor, specifically:

a) The temperature difference between the inlet and outlet of the regenerative heat exchanger unit is less than the set value of the inlet and outlet temperature difference (or the set value of the inlet and outlet temperature difference plus the temperature difference control return difference between the inlet and outlet of the regenerative heat exchanger unit), and the controllable working medium output The opening of the tank valve V3 is increased; the temperature difference between the inlet and outlet of the regenerative heat exchanger unit is greater than the set value of the inlet and outlet temperature difference (or the set value of the inlet and outlet temperature difference plus the return difference controlled by the temperature difference between the inlet and outlet of the regenerative heat exchanger unit) , the opening of the controllable working medium outlet valve V3 is adjusted to be small;

b) The temperature difference between the inlet and outlet of the throttle unit 4 is greater than the set value of the temperature difference between the inlet and outlet (or the set value of the temperature difference between the inlet and outlet plus the return difference controlled by the temperature difference between the inlet and outlet of the throttle unit), and the controllable working medium outlet valve V3 opens The temperature difference between the inlet and outlet of the throttle unit 4 is less than the set value of the temperature difference between the inlet and outlet (or the set value of the temperature difference between the inlet and outlet plus the temperature difference between the inlet and outlet of the throttle unit to control the hysteresis), the controllable working medium outlet valve V3 opening reduced;

c) The suction pressure of the compressor drops to the set value of the suction pressure of the compressor (or the set value plus the suction pressure control hysteresis), and the controllable low-pressure tank outlet valve V5 opens; the suction pressure of the compressor is higher than The set value of the suction pressure of the compressor (or the set value plus the suction pressure control hysteresis), the controllable low-pressure tank outlet valve V5 is closed;

(3) Refrigeration system refrigeration process:

The controllable main circuit valve V1 is in the open state, the controllable bypass tank inlet valve V2 is in the closed state, the controllable working fluid outlet valve V3 and the controllable low pressure tank outlet valve V5 are both in the closed state;

(4) Controlled heating or constant temperature working conditions of the refrigeration system:

The controllable main circuit valve V1 is in the open state, the controllable working medium outlet valve V3 is in the closed state, the opening/closing state of the controllable bypass inlet valve V2 and the controllable low pressure outlet valve V5 is controlled by the control unit (7) according to Desired cooling state determines on/off state;

When the suction pressure of the compressor drops to the set value of the compressor suction pressure (or the set value plus the suction pressure control hysteresis), the controllable bypass tank inlet valve V2 and the controllable low pressure tank outlet valve V5 are opened at the same time ;Until the compressor suction pressure is higher than the set value of the compressor suction pressure (or the set value plus the suction pressure control hysteresis), the controllable bypass tank inlet valve V2 and the controllable low pressure tank outlet valve V5 close at the same time;

(5) Uncontrolled heating conditions of the refrigeration system:

The controllable bypass tank inlet valve V2 and the controllable low pressure tank outlet valve V5 are in the open state; the controllable main circuit valve V1 and the controllable working medium outlet valve V3 are in the closed state.

As described above, the present invention can be preferably carried out.

The implementation of the present invention is not limited by the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods, and are included in within the protection scope of the present invention.

Claims (4)

1. a mixture throttling refrigerating machine operating mode concentration control system, is characterized in that: comprise compressionMachine unit (1), condensate cooler unit (2), Recuperative heat exchanger unit (3), throttling unit (4),Evaporator unit (5), controlled path working medium circulation concentration and flow regulating unit (6), control module (7);

Described controlled path working medium circulation concentration and flow regulating unit (6) comprising: controlled major loop valve(V1), controlled bypass is entered pot valve (V2), controlled working medium tank-outlet valve (V3), is gone out tank check valve (V4)With controlled low pressure tank-outlet valve (V5);

Connected by pipeline therebetween, connected mode is: described controlled major loop valve (V1) entrance point connectsConnect the primary outlet of tee pipe fitting A, second outlet of this tee pipe fitting A connects controlled bypass and enters tankThe entrance point of valve (V2);

Described controlled bypass enters the port of export of pot valve (V2) and the high-pressure inlet end of knockout drum S communicates;

First import of the port of export connecting tee pipe fitting B of described controlled major loop valve (V1), these are three years oldSecond import of way pipe fitting B is connected with the port of export that goes out tank check valve (V4);

Described go out the primary outlet of entrance point connecting tee pipe fitting C of tank check valve (V4), this threewayThe import of pipe fitting C communicates with the top gaseous phase outlet end of knockout drum S;

The entrance point of described controlled working medium tank-outlet valve (V3) is connected with fluid reservoir S outlet at bottom end;

The low pressure line of the port of export of described controlled working medium tank-outlet valve (V3) and Recuperative heat exchanger unit (3)Import is communicated with;

Second outlet of the entrance point connecting tee pipe fitting C of described controlled low pressure tank-outlet valve (V5), canThe port of export and the refrigeration machine low tension loop pipeline connection of control low pressure tank-outlet valve (V5);

The high-pressure refrigerant side outlet of the entrance point of described tee pipe fitting A and condensate cooler unit (2)End is connected;

The port of export of described tee pipe fitting B and Recuperative heat exchanger unit (3) high-pressure refrigerant side-entrance endBe connected;

The low pressure refrigerant side-entrance end of described Recuperative heat exchanger unit (3) and evaporator unit (5)The port of export is connected; Described evaporator unit (5) entrance point is connected with throttling unit (4) port of export;

Described throttling unit (4) entrance point and Recuperative heat exchanger unit (3) high-pressure refrigerant side outlet endBe connected.

2. mixture throttling refrigerating machine operating mode concentration control system according to claim 1, its spyLevy and be: described controlled major loop valve (V1), controlled bypass are entered pot valve (V2), controlled low pressure tank-outlet valve(V5) be power on/off magnet valve.

3. mixture throttling refrigerating machine operating mode concentration control system according to claim 1, its spyLevy and be: the valve that described controlled working medium tank-outlet valve (V3) is electronic or manual step-less adjustment aperture.

4. the controlling party of mixture throttling refrigerating machine operating mode concentration control system described in a claim 1Method, is characterized in that comprising the steps:

(1) start operating performance process:

Controlled major loop valve (V1) is in opening, and controlled bypass is entered pot valve (V2), controlled working mediumTank-outlet valve (V3) and controlled low pressure tank-outlet valve (V5) are all in closed condition; Control module (7) rootWhether reach setting value according to evaporator outlet temperature or Compressor Discharge Pressure parameter, judge whether to turn toControlled cooling operating mode process;

(2) controlled cooling operating mode process:

2-1) control module (7) is according to the parameter of input evaporator outlet temperature or Compressor Discharge PressureJudge with setting value contrast, if the worst hot case of control system in controlled cooling operating mode regulatesMethod is as follows: controlled major loop valve (V1) enters pot valve (V2) and can in opening, controlled bypassThe aperture state of control low pressure tank-outlet valve (V5) in closed condition, controlled working medium tank-outlet valve (V3) is by controllingUnit processed (7) determines according to the parameter of evaporator outlet temperature or Compressor Discharge Pressure, is specially:

A) setting value that the temperature difference is less than this import and export temperature difference is imported and exported in Recuperative heat exchanger unit, and controlled working medium goes out tankValve (V3) aperture tunes up; The setting value that the temperature difference is greater than this import and export temperature difference is imported and exported in Recuperative heat exchanger unit,Controlled working medium tank-outlet valve (V3) aperture is turned down;

B) throttling unit (4) import and export the setting value that the temperature difference is greater than this import and export temperature difference, and controlled working medium goes out tankValve (V3) aperture tunes up; The setting value that the temperature difference is less than this import and export temperature difference is imported and exported in throttling unit (4),Controlled working medium tank-outlet valve (V3) aperture is turned down;

2-2) control module (7) is according to the parameter of input evaporator outlet temperature or Compressor Discharge PressureContrast and judge, if the middle temperature operating mode of control system in controlled cooling operating mode, control method is as follows:Controlled bypass is entered pot valve (V2) in opening, controlled major loop valve (V1) and controlled low extrusion tankValve (V5) is in closed condition, and the aperture state of controlled working medium tank-outlet valve (V3) is by control module (7)Fixed according to input parameter, be specially:

A) setting value that the temperature difference is less than this import and export temperature difference is imported and exported in Recuperative heat exchanger unit, and controlled working medium goes out tankValve (V3) aperture tunes up; The setting value that the temperature difference is greater than this import and export temperature difference is imported and exported in Recuperative heat exchanger unit,Controlled working medium tank-outlet valve (V3) aperture is turned down;

B) throttling unit (4) import and export the setting value that the temperature difference is greater than this import and export temperature difference, and controlled working medium goes out tankValve (V3) aperture tunes up; The setting value that the temperature difference is less than this import and export temperature difference is imported and exported in throttling unit (4),Controlled working medium tank-outlet valve (V3) aperture is turned down;

2-3) control module (7) is according to input evaporator outlet temperature or Compressor Discharge Pressure parameter pairThan judging, if the worst cold case of system in controlled cooling operating mode, control method is as follows: controlledMajor loop valve (V1) is in opening, and controlled bypass is entered pot valve (V2) in closed condition; ControlledThe aperture state of working medium tank-outlet valve (V3) and controlled low pressure tank-outlet valve (V5), by control module (7)Determine according to evaporator outlet temperature or Compressor Discharge Pressure parameter, be specially:

A) setting value that the temperature difference is less than this import and export temperature difference is imported and exported in Recuperative heat exchanger unit, and controlled working medium goes out tankValve (V3) aperture tunes up; The setting value that the temperature difference is greater than this import and export temperature difference is imported and exported in Recuperative heat exchanger unit,Controlled working medium tank-outlet valve (V3) aperture is turned down;

B) throttling unit (4) import and export the setting value that the temperature difference is greater than this import and export temperature difference, and controlled working medium goes out tankValve (V3) aperture tunes up; The setting value that the temperature difference is less than this import and export temperature difference is imported and exported in throttling unit (4),Controlled working medium tank-outlet valve (V3) aperture is turned down;

C) suction pressure of compressor is down to the setting value of suction pressure of compressor, controlled low pressure tank-outlet valve (V5)Open; Suction pressure of compressor is higher than the setting value of suction pressure of compressor, controlled low pressure tank-outlet valve (V5)Close;

(3) refrigeration system process of refrigerastion:

Controlled major loop valve (V1) is in opening, and controlled bypass is entered pot valve (V2) in closing shapeState, controlled working medium tank-outlet valve (V3) and controlled low pressure tank-outlet valve (V5) are all in closed condition;

(4) refrigeration system controlled ramp or constant temperature operating mode:

Controlled major loop valve (V1) is in opening, and controlled working medium tank-outlet valve (V3) is in closing shapeState, controlled bypass is entered the On/Off state of pot valve (V2) and controlled low pressure tank-outlet valve (V5) by controllingOn/Off state is determined according to required refrigerating state in unit (7);

Suction pressure of compressor is down to the setting value of suction pressure of compressor, and controlled bypass is entered pot valve (V2)Open with controlled low pressure tank-outlet valve (V5) simultaneously; Until suction pressure of compressor is pressed higher than compressor air suctionThe setting value of power, controlled bypass enters pot valve (V2) and controlled low pressure tank-outlet valve (V5) is closed simultaneously;

(5) the uncontrolled intensification operating mode of refrigeration system:

Controlled bypass is entered pot valve (V2) and controlled low pressure tank-outlet valve (V5) in opening; Controlled masterReturn valve (V1) and controlled working medium tank-outlet valve (V3) are in closed condition.