A refrigerant cycle system and its control method

Abstract

The present invention discloses a refrigerant circulation system and its control method, relating to the technical field of refrigeration systems. It is used to solve the problem that the refrigerant flow rate and heat transfer amount through the regenerator cannot be adjusted in the prior art, resulting in low energy efficiency and reduced operating reliability of the refrigerant circulation system. The present invention provides a refrigerant circulation system including a compressor, a condenser, a throttling device, and an evaporator connected in series to form a loop, and further including a regenerator. The first pipeline and the second pipeline that exchange heat with each other are included in the regenerator. The first pipeline in the regenerator is connected in series between the condenser and the throttling device, and the second pipeline in the regenerator is connected in series between the evaporator and the compressor. A flow regulating valve is connected in parallel at both ends of the first pipeline or the second pipeline. The present invention is used for refrigeration or heating.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration systems, and particularly to a refrigerant circulation system and a control method thereof. Background Art

[0002] A refrigeration system generally includes a refrigerant circulation system composed of four basic components, namely a compressor, an evaporator, a condenser, and a throttling device, connected by pipes. The refrigerant continuously circulates in the refrigeration cycle system, thereby undergoing state changes and exchanging heat with the outside world.

[0003] In the prior art, the energy efficiency of the refrigerant circulation system is improved by adding a regenerator. The existing regenerator is usually connected in series in the main circuit of the refrigeration cycle system. The first pipeline in the regenerator is arranged between the condenser and the throttling device, and the second pipeline in the regenerator is arranged between the evaporator and the compressor. The refrigerant in the second pipeline in the regenerator can absorb the heat of the refrigerant in the first pipeline in the regenerator. The temperature of the refrigerant in the first pipeline in the regenerator decreases, which can increase the subcooling degree of the refrigerant at the inlet of the throttling device, obtain a lower evaporation temperature, and increase the evaporation capacity of the evaporator; the temperature of the refrigerant in the second pipeline in the regenerator increases, which increases the suction superheat degree of the compressor, avoids liquid carry-over during compressor suction, is beneficial to increasing the exhaust temperature of the compressor, and thus increases the refrigerant flow rate in the refrigerant circulation system.

[0004] However, it is not considered in the prior art that the regenerator is not beneficial in all working conditions. When operating under some extreme working conditions, the regenerator not only cannot improve the energy efficiency of the refrigerant circulation system, but even brings negative effects. For example, when operating under the condition of extremely high indoor ambient temperature and extremely low outdoor ambient temperature, the temperature of the refrigerant at the outlet of the condenser is very high, and the temperature of the refrigerant in the second pipeline in the regenerator is very low. At this time, the temperature difference between the refrigerant in the first pipeline and the second pipeline in the regenerator is very large, and the heat exchange amount of the regenerator is also very large, which will cause a relatively high suction superheat degree and exhaust temperature of the compressor, exceeding the allowable operating temperature of the compressor, thereby causing the compressor to enter the shutdown protection state, and the refrigerant circulation system cannot operate normally. Summary of the Invention

[0005] The refrigerant circulation system and the control method thereof provided by the present invention are used to solve the problems of low energy efficiency and reduced operation reliability of the refrigerant circulation system caused by the inability to adjust the refrigerant flow rate and heat transfer amount passing through the regenerator.

[0006] To achieve the above object, the present invention provides a refrigerant cycle system, which includes a compressor, a condenser, a throttling device, and an evaporator connected in series to form a loop, and further includes a regenerator. The regenerator includes a first pipeline and a second pipeline that exchange heat with each other. The first pipeline in the regenerator is connected in series between the condenser and the throttling device, and the second pipeline in the regenerator is connected in series between the evaporator and the compressor. A flow regulating valve is connected in parallel at both ends of the first pipeline or the second pipeline.

[0007] On the other hand, the present invention also provides a control method for the above refrigerant cycle system, which includes the following steps: adjusting the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant cycle system.

[0008] Compared with the prior art, in the refrigerant cycle system and its control method provided by the embodiments of the present invention, the refrigerant cycle system includes a regenerator. The regenerator includes a first pipeline and a second pipeline that exchange heat with each other. The first pipeline in the regenerator is connected in series between the condenser and the throttling device, and the second pipeline in the regenerator is connected in series between the evaporator and the compressor. A flow regulating valve is connected in parallel at both ends of the first pipeline or the second pipeline. Since the opening degree of the valve port of the flow regulating valve in the refrigerant cycle system determines the refrigerant flow rate and heat transfer amount in the regenerator, when the opening degree of the valve of the flow regulating valve in the refrigerant cycle system is adjusted, the refrigerant flow rate and heat transfer amount passing through the regenerator will also change accordingly, that is, the heat absorbed by the refrigerant in the second pipeline in the regenerator is adjusted, thereby changing the suction superheat degree of the compressor, preventing the suction superheat degree of the compressor from being too high or too low, and avoiding the problems of low energy efficiency and reduced operating reliability of the refrigerant cycle system caused by too high or too low exhaust temperature of the compressor. Description of the Drawings

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0010] Figure 1 It is a schematic structural diagram of the refrigerant cycle system in the embodiment of the present invention, where the flow regulating valve is connected in parallel at both ends of the first pipeline;

[0011] Figure 2 It is a schematic structural diagram of the refrigerant cycle system in the embodiment of the present invention, where the flow regulating valve is connected in parallel at both ends of the second pipeline;

[0012] Figure 3 It is a flowchart of the control method of the refrigerant cycle system in the embodiment of the present invention. Detailed implementation manners

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0014] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0015] The working process of the refrigerant circulation system is as follows: The compressor sucks in the refrigerant gas at low temperature and low pressure from the evaporator through the suction port, compresses it into the refrigerant gas at high temperature and high pressure, and then enters the condenser through the exhaust port of the compressor. The refrigerant gas at high temperature and high pressure releases heat to the fluid medium (water or air) in the condenser and condenses into a liquid at low temperature and high pressure. After being throttled by the throttling device into a liquid at low temperature and low pressure, it enters the evaporator to absorb heat and evaporate into the refrigerant gas at low temperature and low pressure and then enters the compressor for the next cycle, so as to achieve the purpose of circulating heat exchange. In this way, the refrigerant completes a refrigeration cycle through four basic processes of evaporation, compression, condensation and throttling in the circulation system.

[0016] Refer to Figures 1 - 2 , the refrigerant circulation system provided by the embodiment of the present invention includes a compressor 1, a condenser 2, a throttling device 3 and an evaporator 4 connected in series to form a loop in sequence, and further includes a regenerator 5. The regenerator 5 includes a first pipeline and a second pipeline that exchange heat with each other. The first pipeline in the regenerator 5 is connected in series between the condenser 2 and the throttling device 3, and the second pipeline in the regenerator 5 is connected in series between the evaporator 4 and the compressor 1. A flow regulating valve 6 is connected in parallel at both ends of the first pipeline or the second pipeline.

[0017] Compared with the prior art, a flow regulating valve 6 is connected in parallel at both ends of the first pipeline or the second pipeline in the regenerator 5 in the refrigerant circulation system provided by the embodiment of the present invention. Since the opening degree of the valve port of the flow regulating valve 6 in the refrigerant circulation system determines the refrigerant flow rate and the heat transfer amount in the regenerator 5, when the opening degree of the valve of the flow regulating valve 6 in the refrigerant circulation system is adjusted, the refrigerant flow rate and the heat transfer amount passing through the regenerator 5 will also change accordingly. That is, the heat absorbed by the refrigerant in the second pipeline in the regenerator 5 is adjusted, thereby changing the suction superheat degree of the compressor 1 and preventing the suction superheat degree of the compressor 1 from being too high or too low, and avoiding the problems of low energy efficiency and reduced operation reliability of the refrigerant circulation system caused by too high or too low exhaust temperature of the compressor 1.

[0018] Optionally, the flow regulating valve 6 is connected in parallel at both ends of the first pipeline in the regenerator 5. As Figure 1 shown, the refrigerant in the first pipeline in the regenerator 5 is in a liquid state, and the flow rate of the liquid refrigerant in the refrigerant circulation system is relatively slow. Therefore, the resistance of the liquid refrigerant when passing through the flow regulating valve 6 is small, and the suction pressure loss of the compressor 1 is also small, which is beneficial to improving the energy efficiency of the refrigerant circulation system. Optionally, the flow regulating valve 6 is connected in parallel at both ends of the second pipeline in the regenerator 5. As Figure 2 shown, the refrigerant evaporates and absorbs heat in the second pipeline in the regenerator 5 and then becomes gaseous refrigerant, and the flow rate of the gaseous refrigerant is relatively fast. Therefore, both the resistance and the pressure loss of the gaseous refrigerant when passing through the flow regulating valve 6 are large, resulting in a large suction pressure loss of the compressor 1, thereby reducing the energy efficiency of the refrigerant circulation system. Therefore, the embodiment of the present invention preferably adopts the former scheme.

[0019] Optionally, the evaporator 4 in the embodiment of the present invention is a finned tube heat exchanger. Compared with other heat exchangers, the finned tube heat exchanger adopts a double-layer metal material, and the base tube in the finned tube heat exchanger is protected by an aluminum wall, which has good corrosion resistance, good resistance to temperature mutation and vibration, and the refrigerant is not easy to leak; the regenerator 5 can be a shell-and-tube heat exchanger or a plate heat exchanger.

[0020] Further, the refrigerant cycle system further includes a controller, a first temperature detection device 7 for detecting the inlet temperature of the fluid medium that exchanges heat with the refrigerant in the condenser 2, and a second temperature detection device 8 for detecting the inlet temperature of the fluid medium that exchanges heat with the refrigerant in the evaporator 4. The flow regulating valve 6, the first temperature detection device 7, and the second temperature detection device 8 are all connected to the controller. In the embodiment of the present invention, according to the temperatures detected by the first temperature detection device 7 and the second temperature detection device 8, the refrigerant cycle system is divided into different operating conditions. The controller obtains the inlet temperature of the fluid medium entering the condenser 2 from the first temperature detection device 7, and obtains the inlet temperature of the fluid medium that exchanges heat with the refrigerant in the evaporator 4 from the second temperature detection device 8. When the first temperature detection device 7 and the second temperature detection device 8 feedback the detected temperatures to the controller, the controller determines the current operating condition of the refrigerant cycle system by judging the temperatures fed back by the first temperature detection device 7 and the second temperature detection device 8, and then the controller issues a corresponding control command to the flow control valve 6 to control the valve opening of the flow regulating valve 6 to increase or decrease.

[0021] It should be noted that: the compressor 1 can be any form of compressor, such as a single-stage single-compressor or a single-stage double-compressor, and the present invention does not make specific limitations in this regard. For a heat pump system, the condenser 2 is a gas cooler, and the gas cooler can be any one of a shell-and-tube heat exchanger, a plate heat exchanger, or other forms of water-refrigerant heat exchangers; the first temperature detection device 7 is installed on the water inlet pipe of the gas cooler; a water supply pump 15 is further provided on the water inlet pipe of the gas cooler, and the water supply pump 15 is used to introduce or discharge water from the gas cooler. The rotation speed of the water supply pump 15 determines the water flow rate in the gas cooler and the heat exchange rate between the water and the refrigerant in the gas cooler; for a split air conditioner, the first temperature detection device 7 is installed on the indoor unit housing of the air conditioner and on the windward side of the condenser.

[0022] Further, the refrigerant cycle system further includes a third temperature detection device 9 and a fourth temperature detection device 10. Both the third temperature detection device 9 and the fourth temperature detection device 10 are connected to the controller. The third temperature detection device 9 is installed on the connecting pipeline between the condenser 2 and the first pipeline in the regenerator 5, and the fourth temperature detection device 10 is installed on the connecting pipeline between the evaporator 4 and the second pipeline in the regenerator 5. The third temperature detection device 9 is used to detect the temperature of the refrigerant in the first pipeline entering the regenerator 5, and the fourth temperature detection device 10 is used to detect the temperature of the refrigerant in the second pipeline entering the regenerator 5. When the third temperature detection device 9 and the fourth temperature detection device 10 feed back the detected temperatures to the controller, the controller determines the heat transfer amounts in the first pipeline and the second pipeline in the regenerator 5 in the refrigerant cycle system at this time by judging the temperatures fed back by the third temperature detection device 9 and the fourth temperature detection device 10. Subsequently, the controller issues a control command to the flow control valve 6 to control the opening or closing of the valve port of the flow control valve 6.

[0023] Optionally, the refrigerant cycle system further includes a fifth temperature detection device 11 and a pressure detection device 12 both connected to the controller. The fifth temperature detection device 11 and the pressure detection device 12 are both installed at the suction port of the compressor 1. The fifth temperature detection device 11 feeds back the suction temperature detected at the suction port of the compressor 1 to the controller, and the pressure detection device 12 feeds back the suction pressure detected at the suction port of the compressor 1 to the controller. The controller obtains the suction superheat degree of the compressor 1 based on the suction temperature and the suction pressure at the suction port of the compressor 1. Specifically, the suction superheat degree of the compressor 1 is the difference between the suction temperature at the suction port of the compressor 1 and the saturation temperature of the refrigerant corresponding to the suction pressure value at the suction port of the compressor 1.

[0024] Based on the above embodiments, the refrigerant cycle system further includes a fan 13, and the fan 13 is connected to the controller. The fan 13 can promote the heat exchange between the fluid medium and the refrigerant in the evaporator 4, and the rotation speed of the fan 13 determines the heat exchange speed between the fluid medium and the refrigerant in the evaporator 4. When the refrigerant cycle system operates under different operating conditions, the controller can output the duty ratios of different voltage signals. The fan 13 adjusts its rotation speed according to the duty ratios of different voltage signals output by the controller, so that the rotation speed of the fan 13 can be freely adjusted within the range of 0 to 100%, thereby adjusting the air volume and air speed passing through the evaporator 4, and changing the heat exchange speed between the fluid medium and the refrigerant in the evaporator 4.

[0025] Further, the flow control valve 6 can be selected from an electric control valve, a self-operated control valve or a proportional control valve. Compared with other flow control valves, the proportional control valve has a smaller volume and higher control precision, so that the volume occupied by the refrigerant cycle system can be reduced. Therefore, the flow control valve 6 in the embodiments of the present invention preferably adopts a proportional control valve.

[0026] It should be noted that: for the solution where the flow regulating valve 6 in the refrigerant circulation system is connected in parallel at both ends of the first pipeline in the regenerator 5, the valve orifice diameter of the above-mentioned flow regulating valve 6 is close to the diameter of the connecting pipeline between the refrigerant outlet in the condenser 2 and the first pipeline in the regenerator 5. When the valve opening of the flow regulating valve 6 is 100%, the flow resistance of the refrigerant passing through the flow regulating valve 6 is less than the resistance of passing through the first pipeline in the regenerator 5, that is, when the flow regulating valve 6 is fully opened, all or most of the refrigerant passes through the flow regulating valve 6 and enters the throttling device 3. At this time, the refrigerant does not pass through the regenerator 5, or only a very small amount of refrigerant passes through the regenerator 5, and the regenerator 5 does not play or plays a very small heat recovery role; when the valve opening of the flow regulating valve 6 is 0%, that is, when the flow regulating valve 6 is fully closed, all the refrigerant passes through the first pipeline in the regenerator 5, that is, the regenerator 5 fully plays the heat recovery role. When the opening of the flow regulating valve 6 is dynamically adjusted between 0% and 100%, the flow rate of the refrigerant in the first pipeline in the regenerator 5 can be adjusted, so as to realize the adjustment of the heat transfer amount of the refrigerant in the regenerator 5.

[0027] Furthermore, the above-mentioned refrigerant circulation system further includes a gas-liquid separator 14, and the gas-liquid separator 14 is installed on the connecting pipeline between the regenerator 5 and the compressor 1. Among them, the air inlet of the gas-liquid separator 14 is communicated with the outlet of the second pipeline in the regenerator 5, and the air outlet of the gas-liquid separator 14 is communicated with the suction port of the compressor 1. During the operation of the refrigerant circulation system, the gas-liquid separator 14 can not only play the role of gas-liquid separation, but also prevent the compressor 1 from sucking liquid; and compared with directly returning the refrigerant discharged from the evaporator 4 to the suction port of the compressor 1, setting the gas-liquid separator 14 can buffer the pressure of the refrigerant in the gas-liquid separator 14, so as to ensure that the suction pressure of the compressor 1 is relatively stable and the operation is safe and reliable.

[0028] Optionally, the first temperature detection device 7, the second temperature detection device 8, the third temperature detection device 9, the fourth temperature detection device 10 and the fifth temperature detection device 11 in the embodiments of the present invention can be a temperature sensor or an infrared thermometer. Compared with an infrared thermometer, a temperature sensor has a simple structure, is easy to use, has a lower cost, has a high measurement accuracy, can reduce the space occupied by the refrigerant circulation system, and can reduce the cost of the refrigerant circulation system. Therefore, the first temperature detection device 7, the second temperature detection device 8, the third temperature detection device 9, the fourth temperature detection device 10 and the fifth temperature detection device 11 in the embodiments of the present invention are preferably temperature sensors.

[0029] The embodiment of the present invention also provides a control method for the above refrigerant cycle system, including the following steps: adjusting the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant cycle system. When adjusting the valve opening degree of the flow regulating valve in the refrigerant cycle system, the heat absorbed by the refrigerant in the second pipeline in the regenerator is adjusted, thereby changing the suction superheat degree of the compressor, preventing the suction superheat degree of the compressor from being too high or too low, and avoiding the problems of low energy efficiency and reduced operating reliability of the refrigerant cycle system caused by too high or too low exhaust temperature of the compressor. Among them, the adjustment of the opening degree of the flow regulating valve is controlled and executed by a controller. The above controller can be the controller of the refrigerant cycle system or a controller added to the refrigerant cycle system for controlling the opening degree of the flow regulating valve for adjustment.

[0030] The above adjustment of the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant cycle system specifically includes: increasing the opening degree of the flow regulating valve to reduce the suction superheat degree of the refrigerant cycle system; reducing the opening degree of the flow regulating valve to increase the suction superheat degree of the refrigerant cycle system. When the controller sends a control signal to increase the opening degree to the flow regulating valve, after receiving the control signal, the opening degree of the flow regulating valve increases on the basis of the current opening degree, so that the refrigerant flow rate passing through the regenerator is less, the heat transfer amount is less, the heat absorbed by the refrigerant passing through the second pipeline in the regenerator is less, and the suction superheat degree of the refrigerant cycle system is reduced. When the controller sends a control signal to reduce the opening degree to the flow regulating valve, after receiving the control signal, the opening degree of the flow regulating valve decreases on the basis of the current opening degree, so that the refrigerant flow rate passing through the regenerator is more, the heat transfer amount is more, the heat absorbed by the refrigerant passing through the second pipeline in the regenerator is more, and the suction superheat degree of the refrigerant cycle system increases.

[0031] Refer to Figure 3 , the above adjustment of the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant cycle system specifically includes: obtaining the ambient temperature T of the refrigerant cycle system a , and the inlet temperature T of the fluid medium exchanging heat with the refrigerant in the condenser i ; according to the ambient temperature T a and the inlet temperature T i , adjusting the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant cycle system. The above first temperature detection device is used to obtain the inlet temperature T of the fluid medium exchanging heat with the refrigerant in the condenser i , and the above second temperature detection device is used to obtain the ambient temperature T of the refrigerant cycle system a . The controller adjusts the opening degree of the flow regulating valve according to the detected inlet temperature T i and the ambient temperature T aJudge the current operating condition of the refrigerant cycle system. After determining the current operating condition of the refrigerant cycle system, the controller issues a control command to the flow regulating valve. The flow regulating valve adjusts its opening according to this control command to change the suction superheat of the refrigerant cycle system, so that the refrigerant cycle system has an appropriate suction superheat.

[0032] Further, based on the ambient temperature T a and the inlet temperature T i , adjusting the opening of the flow regulating valve to change the suction superheat of the refrigerant cycle system specifically includes: when the ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature, obtain the suction temperature T s of the compressor and the suction pressure P s of the compressor; calculate the target opening SVD(i) of the flow regulating valve, SVD(i)=SVD(i - 1)+K p ×{[T s (i)-T so (i)]-[T s (i - 1)-T so (i - 1)]+K i ×[T s (i)-T so (i)], where SVD(i - 1) is the opening of the flow regulating valve in the previous time, K p and K i are both control constants, T s (i) is the current suction temperature of the compressor, T s (i - 1) is the previous suction temperature of the compressor, T so (i) is the current suction temperature target value of the compressor, T so (i - 1) is the previous suction temperature target value of the compressor; adjust the opening of the flow regulating valve to the target opening SVD(i) to change the suction superheat of the refrigerant cycle system.

[0033] Based on the above embodiments, the current suction temperature target value T so (i)=T cs (i)+K tc (i), the previous suction temperature target value T so (i - 1)=T cs (i - 1)+K tc (i - 1). Wherein, T cs (i) is the saturation temperature corresponding to the current suction pressure P s of the compressor, T cs (i - 1) is the previous suction pressure Ps The corresponding saturation temperature, K tc (i) is the current control target parameter of the compressor, K tc (i - 1) is the previous control target parameter of the compressor. When the suction pressure P of the compressor s remains unchanged, the suction pressure P s The corresponding saturation temperature T cs also remains unchanged, that is, when the suction pressure P of the compressor s remains unchanged, T cs (i) and T cs (i - 1) are equal. At this time, the suction temperature target value T so is represented by the control target parameter K tc The above controller further includes a storage module for storing the previous suction temperature T of the compressor s and the suction pressure P s . When the controller determines that the obtained ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature, the controller obtains the current suction temperature T of the compressor s and the suction pressure P s , and calculates the target opening SVD(i) of the flow regulating valve according to the previous suction temperature T of the compressor s and the suction pressure P s . The controller sends the calculated target opening SVD(i) to the flow regulating valve, and the flow regulating valve adjusts the current opening to the target opening SVD(i) after receiving the target opening SVD(i) to change the suction superheat of the refrigerant circulation system.

[0034] It should be noted that: the above fifth temperature detection device is used to obtain the suction temperature T of the compressor s ; the above pressure detection device is used to obtain the suction pressure P of the compressor s , and obtains the corresponding saturation temperature T s from the obtained suction pressure P of the compressor cs ; the value range of the control constant K p is 1 to 5, and the value range of the control constant K i is 0.5 to 3.5. The control target parameter K tc can be obtained by looking up a table according to the ambient temperature T a and the inlet temperature T i . For example, when the above refrigerant circulation system is operating under the condition that both the current and the previous are at T a > - 10°C and T i ≥ 45°C, the current control target parameter K of the compressor tc(i) is equal to the control target parameter K of the compressor in the previous time. For example, as shown in Table 1, the unit of the ambient temperature T tc and the inlet temperature T a is °C: i

[0035] Table 1 Control target parameter K tc Control target parameter table

[0036]

[0037] Optionally, adjusting the opening degree of the flow regulating valve according to the ambient temperature T a and the inlet temperature T i to change the suction superheat degree of the refrigerant circulation system further includes: when the ambient temperature T a is greater than the second preset ambient temperature and the inlet temperature T i is less than or equal to the first preset inlet temperature, obtaining the refrigerant outlet temperature T gc of the condenser and the refrigerant temperature T g in the gas pipe in the evaporator; when T gc ≥T g , closing the flow regulating valve to increase the suction superheat degree of the refrigerant circulation system; when T gc <T g , adjusting the opening degree of the flow regulating valve to the maximum opening degree to maintain the suction superheat degree of the refrigerant circulation system. The above-mentioned third temperature detection device is used to obtain the refrigerant outlet temperature T gc of the condenser, and the above-mentioned fourth temperature detection device is used to obtain the refrigerant temperature T g in the gas pipe in the evaporator. After the controller obtains the refrigerant outlet temperature T gc of the condenser and the refrigerant temperature T g in the gas pipe in the evaporator, it judges the high and low of the two detected temperatures. When the controller judges that T gc ≥T g , that is, heat is transferred from the first pipeline in the regenerator to the second pipeline in the regenerator, the refrigerant temperature at the outlet of the first pipeline in the regenerator decreases, the evaporation capacity of the evaporator increases, the energy efficiency of the refrigerant circulation system improves, the refrigerant temperature at the outlet of the second pipeline in the regenerator increases, and the suction superheat degree of the refrigerant circulation system increases. Therefore, the heat transfer from the first pipeline in the regenerator to the second pipeline in the regenerator plays a role in increasing the suction superheat degree of the refrigerant circulation system. Subsequently, the controller controls the flow regulating valve to close, and all the refrigerant passes through the regenerator, further increasing the refrigerant temperature in the second pipeline in the regenerator and increasing the suction superheat degree of the refrigerant circulation system. When the controller judges that T gc <T g ​, that is, the second pipeline in the regenerator transfers heat to the first pipeline in the regenerator, the refrigerant temperature at the outlet of the second pipeline in the regenerator decreases, and the suction superheat of the refrigerant circulation system decreases. To avoid the decrease in the suction superheat of the refrigerant circulation system, the controller controls the flow regulating valve to open to the maximum opening, and all or most of the refrigerant passes through the flow regulating valve and enters the evaporator. At this time, no or only a very small amount of refrigerant passes through the first pipeline in the regenerator, and the refrigerant temperature at the outlet of the second pipeline in the regenerator remains unchanged, so that the suction superheat of the refrigerant circulation system remains unchanged.

[0038] Optionally, the above-mentioned adjustment of the opening of the flow regulating valve according to the ambient temperature T a and the inlet temperature T i , to change the suction superheat of the refrigerant circulation system further includes: when the ambient temperature T a is less than or equal to the second preset ambient temperature and the inlet temperature T i is less than or equal to the first preset inlet temperature, or the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature and less than or equal to the second preset inlet temperature, or the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the second preset inlet temperature, the flow regulating valve is closed to increase the suction superheat of the refrigerant circulation system. The controller judges by obtaining the ambient temperature T a and the inlet temperature T i . When the ambient temperature T a is less than or equal to the second preset ambient temperature and the inlet temperature T i is less than or equal to the first preset inlet temperature, both the ambient temperature T a and the inlet temperature T i are relatively low. To ensure the evaporation capacity of the evaporator, it is necessary to reduce the refrigerant temperature entering the throttling device. At this time, the controller controls the flow regulating valve to be fully closed, and all the refrigerant passes through the regenerator. The heat exchange amount of the regenerator is the largest, the temperature of the refrigerant in the first pipeline in the regenerator decreases, the evaporation capacity of the evaporator increases, and the temperature of the refrigerant in the second pipeline of the regenerator increases, and the suction superheat of the refrigerant circulation system increases; similarly, when the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature and less than or equal to the second preset inlet temperature, or the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the second preset inlet temperature, it can ensure that the refrigerant outlet temperature T gc of the condenser is greater than the refrigerant temperature T in the gas pipe of the evaporatorg , the controller controls the flow regulating valve to be fully closed.

[0039] Furthermore, the above refrigerant cycle system further includes a fan, which is used to introduce or export the fluid medium that exchanges heat with the refrigerant in the evaporator. The control method of the above refrigerant cycle system further includes: according to the ambient temperature T of the refrigerant cycle system a , and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i , adjust the rotational speed of the fan. The adjustment of the rotational speed of the fan is executed by the controller. The controller issues a control command to the fan according to the obtained ambient temperature T a and the inlet temperature T i . After receiving the control command, the fan adjusts its own rotational speed and the heat exchange speed between the fluid medium and the evaporator.

[0040] Based on the above embodiments, the adjustment of the rotational speed of the fan according to the ambient temperature T of the refrigerant cycle system a , and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i specifically includes: when the ambient temperature T a is greater than the second preset ambient temperature and the inlet temperature T i is less than or equal to the second preset inlet temperature, or when the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the second preset heat exchange temperature, calculate the target rotational speed R of the fan, where R = -a*T a +b, both a and b are control parameters, and a>0, b>0; adjust the rotational speed of the fan to the target rotational speed R. The target rotational speed R of the fan = -a*T a +b. It can be seen that the higher the ambient temperature T a , the slower the rotational speed of the fan, and the lower the ambient temperature T a , the faster the rotational speed of the fan. The controller calculates the target rotational speed R through the formula R = -a*T a and the inlet temperature T i , and then issues a control command to the fan. After receiving the control command, the fan adjusts the rotational speed of the fan to the target rotational speed R, so that the heat exchange speed between the fluid medium and the evaporator is more appropriate; and the higher the ambient temperature T a +b, the slower the rotational speed of the fan, which is also beneficial to the refrigerant cycle system to achieve the effect of energy saving and consumption reduction. a

[0041] Optionally, the adjustment of the rotational speed of the fan according to the ambient temperature T of the refrigerant cycle system a , and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i, adjusting the rotational speed of the fan further includes: when the ambient temperature T a is less than or equal to the second preset ambient temperature and the inlet temperature T i is less than or equal to the second preset inlet temperature, or when the ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the second preset inlet temperature, adjust the rotational speed of the fan to the maximum rotational speed. To ensure the evaporation capacity of the evaporator, the temperature of the refrigerant entering the evaporator is generally much lower than the ambient temperature. The faster the rotational speed of the fan, the faster the heat exchange speed between the fluid medium and the evaporator. Therefore, the controller controls the rotational speed of the fan to be adjusted to the maximum rotational speed, so that the heat exchange speed between the fluid medium and the refrigerant in the evaporator is the fastest.

[0042] The following further describes adjusting the opening degree of the flow regulating valve to change the suction superheat of the refrigerant cycle system according to the ambient temperature T a of the refrigerant cycle system and the inlet temperature T i of the fluid medium exchanging heat with the refrigerant in the condenser in conjunction with specific embodiments.

[0043] It should be noted that: the range of the ambient temperature T a is generally -35°C to 43°C, and the range of the inlet temperature T i is generally 5°C to 60°C. The above-mentioned first preset ambient temperature is -15°C, the second preset ambient temperature is 7°C, and the third preset ambient temperature is set to 30°C. According to the first preset ambient temperature of -15°C, the second preset ambient temperature of 7°C, and the third preset ambient temperature of 30°C, the range of the ambient temperature T a is divided into four segments. The above-mentioned first preset inlet temperature is 25°C and the second preset inlet temperature is 45°C. According to the first preset inlet temperature of 25°C and the second preset inlet temperature of 45°C, the range of the inlet temperature T i of the fluid medium exchanging heat with the refrigerant in the condenser is divided into three segments. Thus, the refrigerant cycle system is divided into 12 operating conditions. For example, as shown in Table 2:

[0044] Table 2 Division Table of Operating Conditions of Refrigerant Cycle System

[0045]

[0046] When the ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature, that is, when the ambient temperature -35°C < T a ≤ -15°C and the inlet temperature 25°C < T i ≤ 45°C or 25°C < T i≤45°C, referring to Table 2, the operating conditions of the refrigerant cycle system belong to operating condition ⑤ or ⑨. The controller controls the opening of the flow regulating valve to be adjusted to the target opening, and controls the fan speed to be adjusted to the maximum speed.

[0047] When the ambient temperature T a is greater than the second preset ambient temperature and the inlet temperature T i is less than or equal to the first preset inlet temperature, that is, when the ambient temperature 7°C < T a ≤30°C or 30°C < T a ≤43°C, and the inlet temperature 5°C < T i ≤25°C, referring to Table 2, the operating conditions of the refrigerant cycle system belong to operating condition ③ or ④. The controller judges the refrigerant outlet temperature T gc of the condenser and the refrigerant temperature T g in the gas pipe of the evaporator, controls the flow regulating valve to be closed or opened to the maximum opening, and controls the fan speed to be adjusted to the target speed.

[0048] When the ambient temperature T a is less than or equal to the second preset ambient temperature and the inlet temperature T i is less than or equal to the first preset inlet temperature, that is, when the ambient temperature -35°C < T a ≤15°C or 15°C < T a ≤7°C, and the inlet temperature 5°C < T i ≤25°C, referring to Table 2, the operating conditions of the refrigerant cycle system belong to operating condition ① or ②. The controller controls the flow regulating valve to be closed, increases the suction superheat of the refrigerant cycle system, and controls the fan speed to be adjusted to the maximum speed.

[0049] When the ambient temperature T a is greater than the first preset ambient temperature, and the inlet temperature T i is greater than the first preset inlet temperature and less than or equal to the second preset inlet temperature, that is, when the ambient temperature -15°C < T a ≤7°C or 7°C < T a ≤30°C or 30°C < T a ≤43°C, the inlet temperature 25°C < T i ≤45°C, referring to Table 2, the operating conditions of the refrigerant cycle system belong to operating condition ⑥, ⑦ or ⑧. The controller controls the flow regulating valve to be closed, increases the suction superheat of the refrigerant cycle system. If the operating condition of the refrigerant cycle system belongs to operating condition ⑥, controls the fan speed to be adjusted to the maximum speed; if the operating condition of the refrigerant cycle system belongs to operating condition ⑦ or ⑧, controls the fan speed to be adjusted to the target speed.

[0050] When the ambient temperature T a is greater than the first preset ambient temperature, and the inlet temperature Ti When it is greater than the second preset inlet temperature, i.e., ambient temperature - 15°C < T a ≤ 7°C or 7°C < T a ≤ 30°C or 30°C < T a ≤ 43°C, inlet temperature 45°C < T i ≤ 60°C, referring to Table 2, the operating conditions of the refrigerant circulation system belong to operating condition ⑩, or The controller controls the flow regulating valve to close, and all the refrigerant passes through the regenerator, which can increase the suction superheat of the refrigerant circulation system and control the fan speed to be adjusted to the target speed.

[0051] In the description of this specification, specific features, structures, materials, or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0052] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A refrigerant cycle system, the refrigerant cycle system comprising a compressor, a condenser, a throttling device, and an evaporator connected in series to form a loop, characterized in that, The refrigerant cycle system further includes a regenerator, which includes a first pipeline and a second pipeline that exchange heat with each other. The first pipeline in the regenerator is connected in series between the condenser and the throttling device, and the second pipeline in the regenerator is connected in series between the evaporator and the compressor. A flow regulating valve is connected in parallel at both ends of the first pipeline or the second pipeline; Wherein, the refrigerant cycle system further includes: A controller; The first temperature detection device, the first temperature detection device being configured to detect the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i ; Second temperature detection device, the second temperature detection device is configured to detect the ambient temperature T of the refrigerant circulation system a ; The fifth temperature detection device, which is configured to detect the suction temperature T of the compressor s ; and Pressure detection device, the pressure detection device is configured to detect the suction pressure P of the compressor s , The controller is connected to the flow regulating valve, the first temperature detection device, the second temperature detection device, the fifth temperature detection device and the pressure detection device, and the controller is configured such that: When the detected ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature, obtain the suction temperature T s of the compressor and the suction pressure P s ; Calculate the target opening SVD(i) of the flow regulating valve by the following formula SVD(i) = SVD(i - 1)+K p ×{[T s (i)-T so (i)]-[T s (i - 1)-T so (i - 1)]+K i ×[T s (i)-T so (i)] Among them, SVD(i - 1) is the opening degree of the flow regulating valve in the previous time, K p and K i are both control constants, T s (i) is the current suction temperature of the compressor, T s (i - 1) is the previous suction temperature of the compressor, T so (i) is the current suction temperature target value of the compressor, T so (i - 1) is the previous suction temperature target value of the compressor; Adjust the opening of the flow regulating valve to the target opening SVD(i) to change the suction superheat degree of the refrigerant cycle system.

2. The refrigerant cycle system according to claim 1, wherein The refrigerant cycle system further includes: The third temperature detection device, which is used to obtain the refrigerant outlet temperature T of the condenser gc ; and Fourth temperature detection device, which is used to obtain the refrigerant temperature T in the gas pipe of the evaporator g ; Wherein, both the third temperature detection device and the fourth temperature detection device are connected to the controller. The third temperature detection device is installed on the connecting pipeline between the condenser and the first pipeline in the regenerator, and the fourth temperature detection device is installed on the connecting pipeline between the evaporator and the second pipeline in the regenerator.

3. The refrigerant cycle system according to claim 1, wherein Both the fifth temperature detection device and the pressure detection device are installed at the suction port of the compressor.

4. The refrigerant cycle system according to claim 1, wherein The refrigerant cycle system further includes a fan, and the fan is connected to the controller.

5. The refrigerant cycle system according to claim 1, wherein The flow regulating valve is a proportional regulating valve.

6. The refrigerant cycle system according to claim 1, wherein The refrigerant cycle system further includes a gas-liquid separator, and the gas-liquid separator is installed on the connecting pipeline between the regenerator and the compressor.

7. The refrigerant cycle system according to claim 2, wherein, The first temperature detection device, the second temperature detection device, the third temperature detection device and the fourth temperature detection device are all temperature sensors.

8. A control method for the refrigerant cycle system according to any one of claims 1 to 7, characterized in that, The control method includes the following steps: Obtain the ambient temperature T of the refrigerant circulation system a and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i ; According to the ambient temperature T a and the inlet temperature T i adjust the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant circulation system; Wherein, adjusting the opening degree of the flow regulating valve according to the ambient temperature T a and the inlet temperature T i to change the suction superheat degree of the refrigerant circulation system includes: When the ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature, obtain the suction temperature T s of the compressor and the suction pressure P s ; Calculate the target opening SVD(i) of the flow regulating valve by the following formula: SVD(i) = SVD(i - 1)+K p ×{[T s (i)-T so (i)]-[T s (i - 1)-T so (i - 1)]+K i ×[T s (i)-T so (i)] Among them, SVD(i - 1) is the opening degree of the flow regulating valve in the previous time, K p and K i are both control constants, T s (i) is the current suction temperature of the compressor, T s (i - 1) is the previous suction temperature of the compressor, T so (i) is the current suction temperature target value of the compressor, T so (i - 1) is the previous suction temperature target value of the compressor; Adjust the opening of the flow regulating valve to the target opening SVD(i) to change the suction superheat degree of the refrigerant cycle system.

9. The control method of the refrigerant cycle system according to claim 8, characterized in that, According to the ambient temperature T a and the inlet temperature T i Adjusting the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant circulation system specifically includes: Increase the opening of the flow regulating valve to reduce the suction superheat degree of the refrigerant cycle system; Reduce the opening of the flow regulating valve to increase the suction superheat degree of the refrigerant cycle system.

10. The control method of the refrigerant cycle system according to claim 8, characterized in that, Said according to the ambient temperature T a and the inlet temperature T i Adjusting the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant cycle system further includes: When the ambient temperature T a is greater than a second preset ambient temperature, and the inlet temperature T i is less than or equal to a first preset inlet temperature, obtain the refrigerant outlet temperature T gc of the condenser and the refrigerant temperature T g in the gas pipe of the evaporator; When T gc ≥ T g , close the flow regulating valve to increase the suction superheat degree of the refrigerant circulation system; When T gc <T g , adjust the opening degree of the flow regulating valve to the maximum opening degree to maintain the suction superheat degree of the refrigerant circulation system.

11. The control method of the refrigerant cycle system according to claim 8, characterized in that, According to the ambient temperature T a and the inlet temperature T i Adjusting the opening degree of the flow regulating valve to change the suction superheat degree of the refrigerant circulation system further includes: When the ambient temperature T a is less than or equal to the second preset ambient temperature and the inlet temperature T i is less than or equal to the first preset inlet temperature, or when the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the first preset inlet temperature and less than or equal to the second preset inlet temperature, or when the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the second preset inlet temperature, close the flow regulating valve to increase the suction superheat degree of the refrigerant circulation system.

12. The control method of the refrigerant cycle system according to claim 8, characterized in that, The refrigerant cycle system further includes a fan, and the fan is used to introduce or export the fluid medium that exchanges heat with the refrigerant in the evaporator. The control method further includes: According to the ambient temperature T of the refrigerant circulation system a and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i , adjust the rotational speed of the fan.

13. The control method of the refrigerant cycle system according to claim 12, characterized in that, According to the ambient temperature T of the refrigerant cycle system a and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i , adjusting the rotational speed of the fan specifically includes: When the ambient temperature T a is greater than the second preset ambient temperature and the inlet temperature T i is less than or equal to the second preset inlet temperature, or when the ambient temperature T a is greater than the first preset ambient temperature and the inlet temperature T i is greater than the second preset heat exchange temperature, calculate the target speed R of the fan, where R = -a*T a +b, where both a and b are control parameters, and a > 0, b > 0; Adjust the rotation speed of the fan to the target rotation speed R.

14. The control method of the refrigerant cycle system according to claim 12, wherein According to the ambient temperature T of the refrigerant cycle system a and the inlet temperature T of the fluid medium that exchanges heat with the refrigerant in the condenser i , adjusting the rotational speed of the fan further includes: When the ambient temperature T a is less than or equal to the second preset ambient temperature and the inlet temperature T i is less than or equal to the second preset inlet temperature, or the ambient temperature T a is less than or equal to the first preset ambient temperature and the inlet temperature T i is greater than the second preset inlet temperature, adjust the rotational speed of the fan to the maximum rotational speed.

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