Fresh air refrigerating machine with efficient condensation and heat dissipation functions

Abstract

The utility model relates to a fresh air refrigerating machine with an efficient condensation heat dissipation function. The fresh air refrigerating machine comprises a refrigerant circulation flow path, a fresh air flow path and a condensation heat dissipation air flow path. The refrigerant circulating flow path comprises a first refrigerant circulating flow path and a second refrigerant circulating flow path; the first refrigerant circulating flow path comprises a first compressor, a condenser refrigerant channel first module, a first throttling element and a refrigerant channel of a first evaporator; the second refrigerant circulating flow path comprises a second compressor, a condenser refrigerant channel second module, a second throttling element and a refrigerant channel of a second evaporator; condensation heat dissipation air flow paths are symmetrically distributed on the two sides, and four condensers distributed in a staggered mode are arranged on the condensation side of the fresh air refrigerating machine. Compared with the prior art, the efficient condensation heat dissipation mode is adopted, the four heat exchangers are arranged on the condensation side and are ingeniously arranged and reasonably distributed to the two refrigerant circulation loops, and better heat exchange matching of the refrigerant side and the air side is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of fresh air refrigerators, in particular to a fresh air refrigerator with high efficiency in condensation and heat dissipation. Background Art

[0002] Fresh air chillers are suitable for industrial applications that require large-area fresh air treatment, such as in the shipbuilding industry where fresh air ventilation is required for a long time in the cabin. It can cool the fresh air and provide a comfortable environment for the application site. Fresh air chillers usually use the principle of vapor compression refrigeration cycle to cool the outdoor fresh air through the evaporation side heat exchanger and then send it to the application site.

[0003] Direct processing of fresh air is a feature of fresh air chillers. Its load size is directly determined by the fresh air flow and temperature difference. The load scale is large and the energy consumption is relatively high. Unlike traditional air refrigeration equipment, the state of its evaporation and condensation sides are directly affected by the fresh air conditions, making it difficult to achieve optimal control. Especially under high temperature conditions, the condensation temperature of the refrigeration cycle is high, which inhibits the cycle efficiency. Therefore, improving the heat dissipation efficiency on the condensation side has a great impact on improving the overall performance of the fresh air chiller.

[0004] In addition, since it directly processes fresh air from the environment, the fresh air chiller needs to adapt to fresh air conditions under different conditions. Its system load also changes with the environment and application conditions, which brings challenges to the matching and adjustment of the unit. Although in theory the system capacity can be adjusted in the form of a full variable frequency compressor, there are many problems in actual applications: for example, fresh air chillers have high energy consumption and are cost-sensitive, while compressor inverters require additional costs. Most fresh air chillers are mobile and have high reliability requirements such as vibration resistance. It is difficult to balance the vibration characteristics at different frequencies using variable frequency compressors, and it is difficult to always ensure reliable operation. Utility Model Content

[0005] The purpose of the present utility model is to provide a fresh air refrigerator with high-efficiency condensation and heat dissipation in order to overcome the defects of the above-mentioned prior art. The structure adopts a high-efficiency condensation and heat dissipation method. Four heat exchangers are set on the condensation side and cleverly arranged, and reasonably allocated to two refrigerant circulation loops to achieve better heat exchange matching between the refrigerant side and the air side. In terms of control, a component control scheme of a fixed-frequency compressor + a variable-frequency fan is adopted to reduce equipment cost, control complexity, and failure rate, and avoid problems such as heat dissipation and vibration of the variable-frequency compressor. At the same time, with the help of a reasonable combination of two-stage discrete adjustment on the refrigerant side and continuous adjustment of the air volume on the air side, a performance control method comparable to that of the variable-frequency compressor adjustment can be achieved, and the unit can cover a capacity adjustment range of 30% to 100%.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] The utility model provides a fresh air refrigerator with high efficiency condensation and heat dissipation, comprising a refrigerant circulation flow path, a fresh air flow path, and a condensation and heat dissipation air flow path;

[0008] The refrigerant circulation flow path includes a first refrigerant circulation flow path and a second refrigerant circulation flow path;

[0009] The first refrigerant circulation flow path includes a first compressor, a first module of a condenser refrigerant channel, a first throttling element, and a refrigerant channel of a first evaporator connected in sequence;

[0010] The second refrigerant circulation flow path includes a second compressor, a second module of a condenser refrigerant channel, a second throttling element, and a refrigerant channel of a second evaporator connected in sequence;

[0011] The fresh air flow path includes an air passage of a first evaporator, an air passage of a second evaporator, and an air supply fan which are connected in sequence;

[0012] The condensation and heat dissipation air flow path is distributed in a symmetrical form on both sides. The condensation side of the fresh air refrigeration machine is provided with four condensers in a staggered distribution, wherein the first condenser is arranged downstream of the condensation and heat dissipation inlet air flow path on one side, and the second condenser is arranged upstream of the condensation and heat dissipation inlet air flow path on the other side. The refrigerant channels of the first condenser and the second condenser are connected in series and are used for the first refrigerant circulation flow path. The third condenser is arranged downstream of the condensation and heat dissipation inlet air flow path on the same side of the second condenser, and the fourth condenser is arranged upstream of the condensation and heat dissipation inlet air flow path on the same side of the first condenser. The refrigerant channels of the third condenser and the fourth condenser are connected in series and are used for the second refrigerant circulation flow path.

[0013] Furthermore, the fresh air refrigeration machine also includes a condensing and cooling fan, and the condensing and cooling air flow paths on both sides are merged into one path and discharged through the condensing and cooling fan;

[0014] The fresh air flow path is heat-exchange connected to the first refrigerant circulation flow path through the first evaporator, and is heat-exchange connected to the second refrigerant circulation flow path through the second evaporator;

[0015] The first refrigerant circulation flow path and the second refrigerant circulation flow path are in a parallel relationship on the refrigerant side, and in a series and parallel relationship on the air side.

[0016] Further, the first refrigerant circulation flow path includes a first compressor, a refrigerant channel of a first condenser, a refrigerant channel of a second condenser, a first throttling element, and a refrigerant channel of a first evaporator connected in sequence;

[0017] The second refrigerant circulation flow path includes a second compressor, a refrigerant passage of a third condenser, a refrigerant passage of a fourth condenser, a second throttling element, and a refrigerant passage of a second evaporator which are connected in sequence.

[0018] Furthermore, one side of the air inlet of the condensation and heat dissipation air flow path is heat-exchange connected to the second condenser of the first refrigerant circulation flow path and the third condenser of the second refrigerant circulation flow path in sequence, and the other side of the air inlet of the condensation and heat dissipation air flow path is heat-exchange connected to the fourth condenser of the second refrigerant circulation flow path and the first condenser of the first refrigerant circulation flow path in sequence.

[0019] Furthermore, the utility model provides another condensation side heat exchanger connection mode, wherein the first condenser and the third condenser are connected in parallel and used in the first refrigerant circulation flow path;

[0020] The second condenser and the fourth condenser are connected in parallel and used in the second refrigerant circulation flow path.

[0021] Furthermore, one side of the air inlet of the condensation and heat dissipation air flow path is heat-exchange connected to the second condenser of the second refrigerant circulation flow path and the third condenser of the first refrigerant circulation flow path in sequence, and the other side of the air inlet of the condensation and heat dissipation air flow path is heat-exchange connected to the fourth condenser of the second refrigerant circulation flow path and the first condenser of the first refrigerant circulation flow path in sequence.

[0022] Furthermore, the utility model also provides a condensation side heat exchanger arrangement method, that is, two refrigerant circulation paths share a combined condenser, which is simpler in structural arrangement.

[0023] Furthermore, the first compressor and the second compressor are both fixed frequency compressors;

[0024] The air supply fan is a fan of stepless adjustment within a preset frequency conversion range.

[0025] The condensing and cooling fan is a fan with a stepless adjustment mode, or a fan with a stepped adjustment mode with two speeds of high speed and low speed.

[0026] Furthermore, the fresh air inlet and outlet of the fresh air refrigeration machine are both provided with temperature sensors or temperature and humidity sensors;

[0027] The control target of the fresh air refrigerator is the fresh air supply temperature or the return air temperature of the application site;

[0028] The system refrigeration load range of the fresh air refrigerator is calculated based on the state of fresh air collected at the air inlet.

[0029] Furthermore, the first throttling element and the second throttling element are one of a capillary tube, a throttling short tube, a thermal expansion valve or an electronic expansion valve. The technical solution preferably uses an electronic expansion valve to achieve automatic control.

[0030] The utility model discloses a fresh air refrigerator with high efficiency of condensation and heat dissipation. The refrigerant working process is as follows: the low temperature and low pressure refrigerant in the first evaporator is sucked in by the first compressor and compressed to a high temperature and high pressure state. After flowing out of the first compressor, it enters the first condenser to initially release heat to the higher temperature air flowing through it, and then flows through the second condenser to further release heat to the lower temperature air in the air channel on the other side, thereby converting the refrigerant into a supercooled liquid state. The supercooled refrigerant coming out of the second condenser is throttled by the first throttling element to become a low temperature and low pressure two-phase refrigerant, returns to the first evaporator to take heat from the air in the channel on the other side, and is converted into a refrigerant superheated gas again, and continues to be sucked in by the first compressor. The above process is repeated, thereby forming a first refrigerant cycle.

[0031] The low-temperature and low-pressure refrigerant in the second evaporator is sucked in by the second compressor and compressed to a high-temperature and high-pressure state. After flowing out of the second compressor, it enters the third condenser to initially release heat to the higher-temperature air flowing through it, and then flows through the fourth condenser to further release heat to the lower-temperature air in the air channel on the other side, thereby turning into a supercooled liquid state of the refrigerant. The supercooled refrigerant coming out of the fourth condenser is throttled by the second throttling element to become a low-temperature and low-pressure two-phase refrigerant, and returns to the second evaporator to take heat from the air in the channel on the other side, and is transformed into a superheated refrigerant gas again, and continues to be sucked in by the second compressor, repeating the above process, thereby forming a second refrigerant cycle.

[0032] The fresh air treatment process is as follows: driven by the air supply fan, the ambient fresh air first flows through the air channel of the first evaporator, exchanges heat with the low-temperature refrigerant in the refrigerant channel on the other side, and is initially cooled (and may be partially dehumidified); then it flows through the air channel of the second evaporator, also exchanges heat with the refrigerant with a lower temperature in the refrigerant channel, and after being further cooled and dehumidified, it is sent out to the application site by the air supply fan.

[0033] The working process of condensation heat dissipation air is as follows: driven by the condensation heat dissipation fan, the heat dissipation air intake is sucked in from both sides symmetrically, one side first flows through the air channel of the second condenser to exchange heat with the refrigerant of the first refrigerant circulation loop in the channel on the other side to form a larger refrigerant supercooling, and at the same time, the air is initially heated up, and then flows through the air channel of the third condenser to exchange heat with the high-temperature refrigerant discharged from the compressor in the second refrigerant circulation flow path in the refrigerant channel on the other side, taking away most of its condensation heat; similarly, the heat dissipation air intake first flows through the air channel of the fourth condenser on the other side to exchange heat with the refrigerant of the second refrigerant circulation loop in the channel on the other side to form a larger refrigerant supercooling, and at the same time, the air is initially heated up, and then flows through the air channel of the first condenser to exchange heat with the high-temperature refrigerant discharged from the compressor in the first refrigerant circulation flow path in the refrigerant channel on the other side, taking away most of its condensation heat. After the two parts of air are fully exchanged with each other, they are sucked in by the condensation heat dissipation fan and discharged as condensation exhaust air.

[0034] In the present invention, both the first compressor and the second compressor are preferably in the form of fixed-frequency compressors, which is beneficial to reducing equipment cost and control complexity.

[0035] The air supply fan adopts a stepless adjustment form within a certain range, such as conventional 35-50Hz variable frequency adjustment.

[0036] The condensing cooling fan adopts a stepless adjustment method (such as EC variable frequency adjustment) or a high-speed-low-speed two-speed step adjustment method.

[0037] Through the combination of the above main power component control forms and reasonable control algorithm matching, this technical solution can complete the capacity adjustment of the unit within a large range (30% to 100%) with the least possible cost. The control method of this technical solution is:

[0038] Temperature or temperature and humidity sensors are installed at the fresh air inlet and outlet respectively. It allows users to set the fresh air supply temperature as the control target (the return air temperature of the application site can also be monitored and connected to the unit as the control target), and the system cooling load range can be calculated based on the fresh air status collected at the air inlet.

[0039] Compressor start and stop: When the cooling load of the fresh air refrigerator exceeds 50% of the maximum capacity, start the two compressors; if the cooling load of the fresh air refrigerator is less than 50% of the maximum capacity, turn off one of them, and any one can be selectively turned off in combination with the operating time to balance the loss of the compressor.

[0040] Supply fan speed regulation: When the speed of the supply fan is increased, the supply air volume will increase, thereby increasing the cooling capacity of the fresh air chiller; otherwise, the cooling capacity of the fresh air chiller will be reduced. When the cooling load of the fresh air chiller exceeds 50% of the maximum capacity and is in the range of 70% to 100% of the maximum capacity, or the cooling load of the fresh air chiller is less than 50% of the maximum capacity and is in the range of 35% to 50% of the maximum capacity, the supply air volume can be adjusted by changing the speed of the supply fan to achieve the adjustment of the system cooling capacity.

[0041] Condensing cooling fan speed regulation: When the condensing cooling fan runs at high speed, the cooling air volume flowing through the condenser increases, which is beneficial to the heat dissipation of the system and improves the cooling capacity of the fresh air refrigerator; conversely, the cooling capacity of the fresh air refrigerator decreases. In conjunction with the speed regulation of the air supply fan, the adjustment range of the fresh air refrigerator when the cooling load exceeds 50% of the maximum capacity (running two compressors) can be widened to 60% to 100%, and the adjustment range of the fresh air refrigerator when the cooling load is less than 50% of the maximum capacity (running one compressor) can be widened to 30% to 60%, thereby ultimately achieving full coverage of the system capacity in the range of 30% to 100%.

[0042] In actual control, for example, the speed regulation of the air supply fan can adopt feedback control algorithms such as PID. The final result is that when the set fresh air supply temperature is lower than the current actual fresh air supply temperature, the air supply fan speed is increased first, and the condensing cooling fan speed is increased, and then another compressor is turned on as needed (if only one compressor is turned on under the current low load); when the set fresh air supply temperature is higher than the current actual value, the air supply fan speed is reduced, the cooling fan speed is reduced, and one compressor may be shut down (if the two compressors are fully turned on under the current load).

[0043] If the condensing cooling fan also adopts stepless speed regulation, its adjustment range for the cooling capacity of the fresh air refrigeration mechanism has a certain overlap with that of the supply fan, that is, within this range, a slightly higher condensing cooling fan speed + a slightly lower supply fan speed and a slightly lower condensing cooling fan speed + a slightly higher supply fan speed can achieve the same cooling capacity. At this time, the power consumption of the two will be estimated in the control algorithm, and priority will be given to running in a mode with lower total power consumption.

[0044] The above-mentioned slightly lower and slightly higher speed values ​​will be automatically adjusted within the adjustable range of each of the air supply fan and the condensing and cooling fan. For example, one of the methods is that the air supply fan runs in the range of 42-50Hz, and the condensing and cooling fan runs at a low speed; the second equivalent method is that the air supply fan runs in the range of 35-42Hz, and the condensing and cooling fan runs at a high speed.

[0045] The utility model provides a fresh air refrigerator with high efficiency condensation and heat dissipation, which has the following beneficial effects compared with the prior art:

[0046] 1. Higher average evaporation temperature and sensible heat ratio (the efficiency of converting cooling capacity into temperature drop): The first evaporator and the second evaporator exchange heat with the air passing through at two different evaporation temperatures, forming a stepped form. The evaporation temperature of the first evaporator is higher than that of the single evaporator. On the one hand, it can improve the cycle energy efficiency, and on the other hand, it can increase the sensible heat ratio of the heat exchange process (that is, more cooling capacity is used for cooling rather than dehumidification), thereby consuming less power to meet the fresh air cooling needs.

[0047] 2. Efficient condensation and heat dissipation structure: Four small heat exchangers are used on the condensation side and are cleverly arranged to achieve a smaller temperature difference in the heat exchange process between the refrigerant and the air. The temperature of the condensation and heat dissipation inlet air is relatively low, and is used to subcool the refrigerant in the first and second circulation loops in the second condenser and the fourth condenser, respectively, to achieve a greater degree of subcooling and increase the circulation efficiency; the air preliminarily heated by the second and fourth condensers further exchanges heat with the high-temperature refrigerant discharged by the compressor in the second and first refrigerant cycles, taking away the main condensation heat. The heat exchange process is reasonably distributed.

[0048] 3. Lower cost and more reliable control: Although a full frequency conversion compressor can be used to achieve a wide range of unit capacity adjustment, it will lead to an increase in equipment cost, control complexity, and failure rate. It is necessary to consider the anti-electromagnetic interference and heat dissipation of the compressor inverter. In addition, the vibration characteristics of the variable frequency compressor at different speeds are different, requiring more complex research and design to ensure stability and reliability within the full frequency range. The utility model uses a fixed frequency compressor to avoid these problems.

[0049] 4. Performance control method comparable to stepless regulation: The regulation capacity of the fixed-frequency compressor on the refrigerant side is limited. For two parallel circuits, the capacity regulation of only 0% / 50% / 100% discrete gears can be achieved through the start and stop of the compressor, which cannot cover the intermediate load (for example, 75%). Running at a higher load to ensure capacity or using start and stop control will increase unnecessary energy consumption. The utility model further assists the capacity regulation method on the air side. Based on the change of the supply air volume of the air supply fan and the change of the heat dissipation air volume of the condensing heat dissipation fan, the air heat exchange capacity of the evaporation side and the condensation side of the unit are changed respectively, and the air volume delivered to the application site is adjusted, thereby achieving the effect of stepless regulation of the overall capacity of the unit within a larger range. The final unit can cover a range of 30% to 100%, and is more energy-efficient under partial load. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of the principle of Example 1 of the utility model.

[0051] Figure 2 This is a schematic diagram of the principle of Example 2 of the utility model.

[0052] Figure 3This is a schematic diagram of the principle of Example 3 of the utility model.

[0053] In the figure: 1. first evaporator, 2. first compressor, 3. condenser, 3-1. first condenser, 3-2. second condenser, 3-3. third condenser, 3-4. fourth condenser, 4. first throttling element, 5. second evaporator, 6. second compressor, 8. second throttling element, 9. supply air fan, 10. fresh air inlet, 11. fresh air supply, 12. condensation and cooling fan, 13. condensation and cooling inlet, 14. condensation and cooling outlet. DETAILED DESCRIPTION

[0054] The following is a detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0055] Example 1

[0056] See also Figure 1 In this embodiment, a high-efficiency condensation and heat dissipation fresh air refrigerator includes a refrigerant circulation flow path, a fresh air flow path and a condensation and heat dissipation air flow path.

[0057] This embodiment includes two independent refrigerant circulation flow paths, namely a first refrigerant circulation flow path and a second refrigerant circulation flow path.

[0058] The first refrigerant circulation flow path includes a first compressor 2 , a refrigerant passage of a first condenser 3 - 1 , a refrigerant passage of a second condenser 3 - 2 , a first throttling element 4 and a refrigerant passage of a first evaporator 1 , which are connected in sequence.

[0059] The second refrigerant circulation flow path includes a second compressor 6 , a refrigerant passage of the third condenser 3 - 3 , a refrigerant passage of the fourth condenser 3 - 4 , a second throttling element 8 , and a refrigerant passage of the second evaporator 5 , which are connected in sequence.

[0060] The fresh air flow path includes an air inlet 10 , an air passage of the first evaporator 1 , an air passage of the second evaporator 5 , an air supply fan 9 and an air supply 11 in sequence.

[0061] The condensation and heat dissipation air flow path is distributed in a symmetrical manner on both sides, with one side being the air inlet 13, the air passage of the second condenser 3-2, and the air passage of the third condenser 3-3 in sequence; the other side being the air inlet 13, the air passage of the fourth condenser 3-4, and the air passage of the first condenser 3-1 in sequence. The two sides are combined and then discharged through the condensation and heat dissipation fan 12.

[0062] The fresh air flow path is heat-exchange connected to the first refrigerant circulation flow path through the first evaporator 1 , and is heat-exchange connected to the second refrigerant circulation flow path through the second evaporator 5 .

[0063] One side of the air inlet of the condensation and heat dissipation air flow path is heat-exchange connected to the second condenser 3-2 of the first refrigerant circulation flow path and the third condenser 3-3 of the second refrigerant circulation flow path in sequence, and the other side of the air inlet is heat-exchange connected to the fourth condenser 3-4 of the second refrigerant circulation flow path and the first condenser 3-1 of the first refrigerant circulation flow path in sequence.

[0064] The first refrigerant circulation flow path and the second refrigerant circulation flow path are in a parallel relationship on the refrigerant side, and are in a more complicated series-parallel relationship on the air side.

[0065] In this embodiment, four heat exchangers are arranged on the condensation side and are staggered in distribution, wherein the first condenser 3-1 is arranged downstream of the condensation and heat dissipation inlet air flow path on one side, and the second condenser 3-2 is arranged upstream of the condensation and heat dissipation inlet air flow path on the other side, and the refrigerant channels of the two are connected in series for the first refrigerant circulation flow path; at the same time, the third condenser 3-3 is arranged downstream of the condensation and heat dissipation inlet air flow path on the same side of the second condenser 3-2, and the fourth condenser 3-4 is arranged upstream of the condensation and heat dissipation inlet air flow path on the same side of the first condenser 3-1, and the refrigerant channels of the two are connected in series for the second refrigerant circulation flow path.

[0066] The first throttling element and the second throttling element in this embodiment are one of a capillary tube, a throttling short tube, a thermal expansion valve or an electronic expansion valve. The electronic expansion valve is preferably used in this technical solution to achieve automatic control.

[0067] The refrigerant working process of this embodiment is as follows: the low-temperature and low-pressure refrigerant in the first evaporator 1 is sucked in by the first compressor 2 and compressed to a high-temperature and high-pressure state, flows out of the first compressor 2 and enters the first condenser 3-1 to initially release heat to the higher-temperature air flowing through it, and then flows through the second condenser 3-2 to further release heat to the lower-temperature air in the air channel on the other side, thereby turning into a refrigerant supercooled liquid state. The supercooled refrigerant coming out of the second condenser 3-2 is throttled by the first throttling element 4 to become a low-temperature and low-pressure two-phase refrigerant, returns to the first evaporator 1 to take heat from the air in the channel on the other side, and is transformed into a refrigerant superheated gas again, and continues to be sucked in by the first compressor 2, and the above process is repeated, thereby forming a first refrigerant cycle.

[0068] The low-temperature and low-pressure refrigerant in the second evaporator 5 is sucked in by the second compressor 6 and compressed to a high-temperature and high-pressure state. After flowing out of the second compressor 6, it enters the third condenser 3-3 to initially release heat to the higher-temperature air flowing through it, and then flows through the fourth condenser 3-4 to further release heat to the lower-temperature air in the air channel on the other side, thereby turning into a refrigerant supercooled liquid state. The supercooled refrigerant coming out of the fourth condenser 3-4 is throttled by the second throttling element 8 to become a low-temperature and low-pressure two-phase refrigerant, and returns to the second evaporator 5 to take heat from the air in the channel on the other side, and is transformed into a refrigerant superheated gas again, and continues to be sucked in by the second compressor 6, and the above process is repeated, thereby forming a second refrigerant cycle.

[0069] The fresh air treatment process of this embodiment is as follows: driven by the air supply fan 9, the ambient fresh air first flows through the air channel of the first evaporator 1, exchanges heat with the low-temperature refrigerant in the refrigerant channel on the other side, and is initially cooled (and may be partially dehumidified); then flows through the air channel of the second evaporator 5, also exchanges heat with the refrigerant with a lower temperature in the refrigerant channel, and after being further cooled and dehumidified, is sent out to the application site by the air supply fan 9.

[0070] The condensation and heat dissipation air working process of this embodiment is as follows: under the drive of the condensation and heat dissipation fan 12, the heat dissipation air inlet 13 is sucked in symmetrically from both sides, one side first flows through the air channel of the second condenser 3-2 to exchange heat with the refrigerant of the first refrigerant circulation loop in the channel on the other side to form a larger refrigerant supercooling, and at the same time the air is initially heated up, and then flows through the air channel of the third condenser 3-3, and exchanges heat with the high-temperature refrigerant discharged from the compressor 6 in the second refrigerant circulation path in the refrigerant channel on the other side, taking away most of its condensation heat; similarly, the heat dissipation air inlet 13 first flows through the air channel of the fourth condenser 3-4 on the other side to exchange heat with the refrigerant of the second refrigerant circulation loop in the channel on the other side to form a larger refrigerant supercooling, and at the same time the air is initially heated up, and then flows through the air channel of the first condenser 3-1, and exchanges heat with the high-temperature refrigerant discharged from the compressor 2 in the first refrigerant circulation path in the refrigerant channel on the other side, taking away most of its condensation heat. After sufficient heat exchange between the two parts of air, the air is sucked into the condensation and heat dissipation fan 12 and discharged as condensation exhaust air 14.

[0071] The structural features and beneficial effects of this embodiment are as follows: (1) The first evaporator 1 and the second evaporator 5 exchange heat with the air flowing through them at two different evaporation temperatures, forming a stepped form. The evaporation temperature of the first evaporator 1 is higher than that of the single evaporator. On the one hand, it can improve the cycle energy efficiency, and on the other hand, it can increase the sensible heat ratio of the heat exchange process (that is, more cooling capacity is used to meet the cooling rather than dehumidification), thereby consuming less power to meet the fresh air cooling needs. (2) Four small heat exchangers are used on the condensation side and are cleverly arranged to achieve a smaller temperature difference in the heat exchange process between the refrigerant and the air. The temperature of the condensation heat dissipation inlet air 13 is relatively low, and is used to supercool the refrigerant in the first and second circulation loops in the second condenser 3-2 and the fourth condenser 3-4, respectively, to achieve a greater degree of supercooling and increase the cycle efficiency; the air preliminarily heated by the second and fourth condensers further exchanges heat with the high-temperature refrigerant discharged from the compressor in the second and first refrigerant cycles, taking away the main condensation heat. The heat exchange process is reasonably distributed.

[0072] In this embodiment, both the first compressor 2 and the second compressor 6 are preferably fixed-frequency compressors, which is beneficial to reducing equipment cost and control complexity.

[0073] In this embodiment, the air supply fan 9 adopts a stepless adjustment form within a certain range, such as a conventional 35-50 Hz variable frequency adjustment.

[0074] In this embodiment, the condensing and cooling fan 12 adopts a stepless adjustment method (such as EC variable frequency adjustment) or a stepped adjustment method with two speeds of high speed and low speed.

[0075] Through the combination of the above main power component control forms and reasonable control algorithm matching, this technical solution can complete the capacity adjustment of the unit within a large range (30% to 100%) with the least possible cost. The control method of this technical solution is:

[0076] Temperature or temperature and humidity sensors are respectively set at the fresh air inlet 10 and the air outlet 11. The user is allowed to set the fresh air supply temperature as the control target (the return air temperature of the application site can also be monitored and connected to the unit as the control target), and the system cooling load range is calculated based on the fresh air state collected at the air inlet 10.

[0077] Compressor start and stop: When the cooling load of the fresh air refrigerator exceeds 50% of the maximum capacity, start the two compressors; if the cooling load of the fresh air refrigerator is less than 50% of the maximum capacity, turn off one of them, and any one can be selectively turned off in combination with the operating time to balance the loss of the compressor.

[0078] Speed ​​regulation of air supply fan 9: When the speed of the air supply fan increases, the air supply volume will increase, thereby increasing the cooling capacity of the fresh air refrigerator; otherwise, the cooling capacity of the fresh air refrigerator will be reduced. When the cooling load of the fresh air refrigerator exceeds 50% of the maximum capacity and is in the range of 70% to 100% of the maximum capacity, or the cooling load of the fresh air refrigerator is less than 50% of the maximum capacity and is in the range of 35% to 50% of the maximum capacity, the air supply volume can be adjusted by changing the speed of the air supply fan 9 to achieve the adjustment of the cooling capacity of the system.

[0079] Condensing cooling fan 12 speed regulation: When the condensing cooling fan runs at high speed, the cooling air volume flowing through the condenser increases, which is beneficial to the heat dissipation of the system and improves the cooling capacity of the fresh air refrigerator; conversely, the cooling capacity of the fresh air refrigerator decreases. In conjunction with the speed regulation of the air supply fan, the adjustment range of the fresh air refrigerator when the cooling load exceeds 50% of the maximum capacity (running two compressors) can be widened to 60% to 100%, and the adjustment range of the fresh air refrigerator when the cooling load is less than 50% of the maximum capacity (running one compressor) can be widened to 30% to 60%, thereby ultimately achieving full coverage of the system capacity in the range of 30% to 100%.

[0080] In actual control, for example, the speed regulation of the blower can adopt feedback control algorithms such as PID. The final result is that when the set fresh air supply temperature is lower than the current actual fresh air supply temperature, the speed of the supply fan 9 is increased first, and the speed of the condensing cooling fan 12 is increased, and then another compressor is turned on as needed (if only one compressor is turned on under the current low load); when the set fresh air supply temperature is higher than the current actual value, the speed of the blower decreases, the speed of the cooling fan decreases, and one compressor may be shut down (if the two compressors are fully turned on under the current load).

[0081] If the condensing and cooling fan 12 also adopts stepless speed regulation, its adjustment range of the refrigeration capacity of the fresh air refrigeration mechanism has a certain overlap with that of the supply fan 9, that is, within this range, a slightly higher condensing and cooling fan 12 speed + a slightly lower supply fan 9 speed and a slightly lower condensing and cooling fan 12 speed + a slightly higher supply fan 9 speed can achieve the same cooling capacity. At this time, the power consumption of the two will be estimated in the control algorithm, and priority will be given to running in a mode with lower total power consumption.

[0082] The beneficial effects of the control component form and control scheme described in this embodiment are as follows: (1) Although a full-frequency compressor can be used to achieve unit capacity adjustment within a wide range, it will lead to an increase in equipment cost, control complexity, and failure rate. It is necessary to consider issues such as the compressor inverter's anti-electromagnetic interference and inverter heat dissipation. In addition, the vibration characteristics of the variable-frequency compressor at different speeds are different, requiring more complex research and design to ensure stability and reliability within the full frequency range. The use of a fixed-frequency compressor can avoid these problems. (2) The adjustment capacity of a fixed-frequency compressor is limited. For the two parallel circuits in this embodiment, the compressor can only achieve capacity adjustment of 0% / 50% / 100% discrete gears through start-stop, which cannot cover intermediate loads (for example, 75%). Running at a higher load to ensure capacity or using start-stop control will increase unnecessary energy consumption. This embodiment adopts the air side capacity adjustment method, based on the air supply fan 9 changing the air supply volume and the condensing heat dissipation fan 12 changing the heat dissipation volume, respectively changing the air heat exchange capacity of the evaporation side and the condensation side of the unit, adjusting the air volume sent to the application site, and thus achieving the effect of stepless adjustment of the overall capacity of the unit in a larger range. The unit can eventually cover a range of 30% to 100%, and is more energy-efficient under partial load.

[0083] Example 2

[0084] This embodiment sees Figure 2 , the principle and control scheme are consistent with those of Example 1, the difference lies in the arrangement of the condenser structure. In this embodiment, the condenser at the top also forms a ladder form. The first condenser 3-1 and the third condenser 3-3 are connected in parallel and used in the first refrigerant circulation flow path. The second condenser 3-2 and the fourth condenser 3-4 are connected in parallel and used in the second refrigerant circulation flow path. The condensation heat dissipation inlet 13 first passes through the second condenser 3-2 and the fourth condenser 3-4 symmetrically on both sides to be initially heated, and then flows through the third condenser 3-3 and the first condenser 3-1 to further be used for heat dissipation of the higher temperature condenser. Thus, a ladder condensation temperature is formed, and the condensation temperature of the first refrigerant circulation flow path is higher than that of the second refrigerant circulation flow path. Combined with the ladder form of the evaporation side (the evaporation temperature of the first refrigerant circulation flow path is also higher), the compression ratio of the two ladder sub-cycles is smaller than that of the single cycle, which is conducive to improving the cycle performance. The structural selection in this embodiment and Example 1 can be selected according to the actual process manufacturing difficulty, the advantages and disadvantages under the commonly used environmental conditions, etc.

[0085] Example 3

[0086] This embodiment sees Figure 3 The principle and control scheme are consistent with those of embodiment 1, except that the two refrigerant cycles share the combined condenser 3. In comparison, the energy efficiency of this embodiment is slightly reduced, but the complexity of the pipeline connection is lower and the structural layout is simpler.

[0087] The embodiments of the present invention are described according to two refrigerant cycles, but the number of refrigerant cycles is not restricted. The disclosed principles can obviously be extended to several identical or similar refrigerant cycles, and the heat exchangers can be arranged in various ways in the air flow path, which still falls within the scope of protection of the present invention.

[0088] In the present invention, the words "first", "second" and the like are used to define components. Those skilled in the art should know that the words "first", "second" and the like are used only to facilitate the distinction of components in description. If not otherwise stated, the above words have no special meanings.

[0089] The above embodiments do not fully display all the components of the refrigerant cycle and the air flow path. During the implementation process, common refrigeration accessories such as high-pressure liquid storage tanks, gas-liquid separators, oil separators, filters, dryers, etc. are set in the refrigerant circuit, and air treatment accessories such as air filters, mufflers, humidifiers, heaters, sterilization devices, etc. are set in the air flow path. Or heat exchangers, fans and air valves are added without departing from the spirit of the technical solution of the utility model. These cannot be regarded as substantial improvements to the utility model and should fall within the scope of protection of the utility model.

[0090] The above description of the embodiments is to facilitate the understanding and use of the utility model by those skilled in the art. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the utility model is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the utility model without departing from the scope of the utility model should be within the scope of protection of the utility model.

Claims

1. A fresh air refrigerator with high efficiency condensation and heat dissipation, characterized in that: It includes a refrigerant circulation flow path, a fresh air flow path, and a condensation and heat dissipation air flow path; The refrigerant circulation flow path includes a first refrigerant circulation flow path and a second refrigerant circulation flow path; The first refrigerant circulation flow path comprises a first compressor (2), a first module of a condenser refrigerant channel, a first throttling element (4), and a refrigerant channel of a first evaporator (1) connected in sequence; The second refrigerant circulation flow path comprises a second compressor (6), a second condenser refrigerant channel module, a second throttling element (8), and a refrigerant channel of a second evaporator (5) connected in sequence; The fresh air flow path comprises an air passage of a first evaporator (1), an air passage of a second evaporator (5), and an air supply fan (9) which are connected in sequence; The condensation and heat dissipation air flow path is distributed in a bilaterally symmetrical manner. The condensation side of the fresh air refrigeration machine is provided with four staggeredly distributed condensers, wherein the first condenser (3-1) is arranged downstream of the condensation and heat dissipation inlet air flow path on one side, and the second condenser (3-2) is arranged upstream of the condensation and heat dissipation inlet air flow path on the other side. The refrigerant channels of the first condenser (3-1) and the second condenser (3-2) are connected in series and used for the first refrigerant circulation flow path. The third condenser (3-3) is arranged downstream of the condensation and heat dissipation inlet air flow path on the same side as the second condenser (3-2). The fourth condenser (3-4) is arranged upstream of the condensation and heat dissipation inlet air flow path on the same side as the first condenser (3-1). The refrigerant channels of the third condenser (3-3) and the fourth condenser (3-4) are connected in series and used for the second refrigerant circulation flow path.

2. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 1, characterized in that: The fresh air refrigeration machine further comprises a condensation and heat dissipation fan (12), and the condensation and heat dissipation air flow paths on both sides are converged into one path and discharged through the condensation and heat dissipation fan (12); The fresh air flow path is heat-exchange connected to the first refrigerant circulation flow path through the first evaporator (1), and is heat-exchange connected to the second refrigerant circulation flow path through the second evaporator (5); The first refrigerant circulation flow path and the second refrigerant circulation flow path are in a parallel relationship on the refrigerant side, and in a series and parallel relationship on the air side.

3. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 1, characterized in that: The first refrigerant circulation flow path comprises a first compressor (2), a refrigerant channel of a first condenser (3-1), a refrigerant channel of a second condenser (3-2), a first throttling element (4), and a refrigerant channel of a first evaporator (1) which are connected in sequence; The second refrigerant circulation flow path comprises a second compressor (6), a refrigerant channel of a third condenser (3-3), a refrigerant channel of a fourth condenser (3-4), a second throttling element (8), and a refrigerant channel of a second evaporator (5) which are connected in sequence.

4. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 3, characterized in that: One side of the air inlet of the condensation and heat dissipation air flow path is heat-exchangeably connected to the second condenser (3-2) of the first refrigerant circulation flow path and the third condenser (3-3) of the second refrigerant circulation flow path in sequence, and the other side of the air inlet of the condensation and heat dissipation air flow path is heat-exchangeably connected to the fourth condenser (3-4) of the second refrigerant circulation flow path and the first condenser (3-1) of the first refrigerant circulation flow path in sequence.

5. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 1, characterized in that: The first condenser (3-1) and the third condenser (3-3) are connected in parallel and used in a first refrigerant circulation flow path; The second condenser (3-2) and the fourth condenser (3-4) are connected in parallel and are used in a second refrigerant circulation flow path.

6. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 5, characterized in that: One side of the air inlet of the condensation and heat dissipation air flow path is heat-exchangeably connected to the second condenser (3-2) of the second refrigerant circulation flow path and the third condenser (3-3) of the first refrigerant circulation flow path in sequence, and the other side of the air inlet of the condensation and heat dissipation air flow path is heat-exchangeably connected to the fourth condenser (3-4) of the second refrigerant circulation flow path and the first condenser (3-1) of the first refrigerant circulation flow path in sequence.

7. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 1, characterized in that: The first compressor (2) and the second compressor (6) are both fixed-frequency compressors.

8. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 1, characterized in that: The air supply fan (9) is a fan of stepless adjustment type within a preset frequency conversion range.

9. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 2, characterized in that: The condensing and cooling fan (12) is a fan with a stepless adjustment mode, or a fan with a step-by-step adjustment mode with two speeds of high speed and low speed.

10. The fresh air refrigerator with high efficiency condensation and heat dissipation according to claim 1, characterized in that: The fresh air inlet and outlet of the fresh air refrigerator are both provided with temperature sensors or temperature and humidity sensors.

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