Refrigeration system

Abstract

The utility model provides a refrigerating system, and belongs to the technical field of refrigeration. The refrigerating system comprises a compressor, a condenser, a fluorine pump, a first expansion valve, a first evaporator and a second evaporator. An outlet of the compressor, the condenser, the fluorine pump, the first expansion valve, the first evaporator and an inlet of the compressor are sequentially communicated. An inlet of the second evaporator communicates with an outlet of the fluorine pump, and an outlet of the second evaporator communicates with an inlet of the condenser. In the mixed refrigeration mode, one part of a refrigerant output by the fluorine pump is input into the condenser through the first expansion valve, the first evaporator and the compressor in sequence, and the other part of the refrigerant is input into the condenser through the second evaporator. Thus, in the mixed refrigeration mode, the refrigeration system comprises two refrigeration circulation loops. Wherein one circulation loop is composed of the fluorine pump, the second evaporator, the condenser and the fluorine pump, a compressor and an expansion valve are not included in the circulation loop, a refrigerant is driven by the fluorine pump to circularly flow, an external natural cold source is fully utilized, and the energy efficiency of the refrigerating system is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of cooling technology, in particular to a refrigeration system. BACKGROUND

[0002] The refrigeration system of the machine room of the data center needs to cool all the year round, and the energy efficiency index of the refrigeration system has become an important index for the construction of the data center.

[0003] The refrigeration system in the related art includes a compressor, a condenser, a fluorine pump, an expansion valve and an evaporator which are sequentially connected and form a refrigeration cycle, and a first bypass pipeline for bypassing the compressor and a second bypass pipeline for bypassing the fluorine pump. The refrigeration system includes a compressor refrigeration mode, a fluorine pump refrigeration mode and a mixed refrigeration mode. When the outdoor temperature is relatively high, the refrigeration system operates in the compressor refrigeration mode, the compressor works, and the first bypass pipeline is turned off. The fluorine pump is closed, and the second bypass pipeline is turned on. When the outdoor temperature is relatively low, the refrigeration system operates in the fluorine pump refrigeration mode, the compressor is turned off, and the first bypass pipeline is turned on. The fluorine pump is turned on, and the second bypass pipeline is turned off. When the outdoor temperature is neither too high nor too low (i.e. in the transition temperature zone), the refrigeration system operates in the mixed refrigeration mode, the compressor and the fluorine pump work at the same time, and the first bypass pipeline and the second bypass pipeline are both turned off.

[0004] However, the fluorine pump is used to pressurize the refrigerant, and the expansion valve is used to throttle and depressurize the refrigerant to prevent the evaporator from outputting liquid refrigerant to the compressor. Therefore, in the mixed refrigeration mode, the fluorine pump pressurizes the refrigerant, which is immediately depressurized by the expansion valve, thereby increasing the power consumption of the fluorine pump and reducing the energy efficiency of the refrigeration system. UTILITY MODEL CONTENT

[0005] The present disclosure provides a refrigeration system. The refrigeration system includes two refrigeration cycle circuits in the mixed refrigeration mode, one of which does not include a compressor, and the fluorine pump drives the refrigerant to circulate, fully utilizes the natural cold source of the outside world, and improves the energy efficiency of the refrigeration system in the mixed refrigeration mode. The technical scheme of the refrigeration system is as follows.

[0006] The present disclosure provides a refrigeration system. The refrigeration system includes a compressor, a condenser, a fluorine pump, a first expansion valve, a first evaporator and a second evaporator. The fluorine pump is used to output refrigerant to the first expansion valve and the second evaporator. The first expansion valve is used to output refrigerant to the first evaporator, the first evaporator is used to output refrigerant to the compressor, and the compressor is used to output refrigerant to the condenser. The second evaporator is used to output refrigerant to the condenser. The condenser is used to output refrigerant to the fluorine pump.

[0007] The technical scheme provided by the present disclosure is that when the fluorine pump and the compressor are both turned on, the refrigeration system comprises two refrigeration circulating loops. The first circulating loop is compressor-condenser-fluorine pump-first expansion valve-first evaporator-compressor. The second circulating loop is fluorine pump-second evaporator-condenser-fluorine pump. It can be seen that the compressor is not included in the second circulating loop, so that the throttling pressure reduction of the expansion valve is not needed, and the phenomenon that the fluorine pump is immediately reduced in pressure by the expansion valve after the fluorine pump is increased in pressure is not caused. In the second circulating loop, the refrigerant is circulated and flows by the fluorine pump, and the natural cold source in the outside world is fully utilized, so that the energy consumption of the refrigeration system in the mixed refrigeration mode is reduced, and the energy efficiency of the refrigeration system is improved.

[0008] In addition, since the compressor participates in the work in the first circulating loop, the refrigeration capacity of the refrigeration system can meet the demand of the indoor. The compressor can adjust the flow of the refrigerant in the two circulating loops by adjusting the running frequency, so as to take into account the refrigeration demand of the indoor and the energy efficiency of the refrigeration system.

[0009] In an implementation manner, the outlet of the second evaporator is connected to the inlet of the condenser through a first pipeline, and is also connected to the inlet of the compressor through a second pipeline. The second evaporator is used to output the refrigerant to the condenser through the first pipeline, or output the refrigerant to the compressor through the second pipeline. In this way, the second evaporator can also output the refrigerant to the compressor, so that the second evaporator can also participate in the refrigeration in the working condition that the compressor works and the fluorine pump is closed.

[0010] In an implementation manner, the refrigeration system further comprises a second bypass pipeline, two ends of the second bypass pipeline are connected to the inlet and the outlet of the fluorine pump respectively. The condenser is also used to output the refrigerant to the second bypass pipeline, and the second bypass pipeline is used to connect the outlet of the condenser and the first expansion valve, and the outlet of the condenser and the second evaporator. When the fluorine pump is closed, the second bypass pipeline is connected and bypasses the fluorine pump, so that the refrigerant circulating loop can normally flow in the case that the fluorine pump is closed.

[0011] In an implementation manner, when the compressor and the fluorine pump are both turned on, the second bypass pipeline is closed, the first pipeline is connected, and the second pipeline is closed. When the compressor is turned on and the fluorine pump is closed, the second bypass pipeline is connected, the first pipeline is closed, and the second pipeline is connected.

[0012] In an implementation manner, the refrigeration system further comprises a second expansion valve, the second expansion valve is used to receive the refrigerant output by the fluorine pump or the second bypass pipeline, and output the refrigerant to the second evaporator. When the compressor is turned on and the fluorine pump is closed, the second evaporator outputs the refrigerant to the compressor, so that the second expansion valve can control the superheat degree of the refrigerant output by the second evaporator, so as to prevent the liquid refrigerant from entering the compressor, and ensure the reliability of the compressor.

[0013] In an implementation, when the compressor and the fluorine pump are both turned on, the second expansion valve is fully open. Wherein, since the second evaporator outputs refrigerant to the condenser when the compressor and the fluorine pump are both turned on, and does not output to the compressor. Therefore, the second expansion valve does not need to control the superheat degree of the refrigerant output by the second evaporator, so it can be in a fully open state. Wherein, the fully open second expansion valve does not throttle the refrigerant.

[0014] The technical solution provided by the present disclosure is that when the compressor and the fluorine pump are both turned on, the second expansion valve is fully open, the first pipeline is turned on, and the second pipeline is turned off, so that the refrigeration system includes two refrigerant circulation loops. The first circulation loop is compressor-condenser-fluorine pump-first expansion valve-first evaporator-compressor. The second circulation loop is fluorine pump-fully open second expansion valve-second evaporator-first pipeline-condenser-fluorine pump. The fully open second expansion valve does not throttle the refrigerant, so in the second circulation loop, the phenomenon that the fluorine pump pressurizes the refrigerant and then the second expansion valve immediately depressurizes the refrigerant does not occur. In the second circulation loop, the fluorine pump drives the circulation of the refrigerant, fully utilizes the natural cold source from the outside, thereby reducing the energy consumption of the refrigeration system in the mixed refrigeration mode and improving the energy efficiency of the refrigeration system.

[0015] In an implementation, when the compressor is turned on and the fluorine pump is turned off, the second expansion valve controls the superheat degree of the refrigerant output by the second evaporator. Wherein, when the compressor is turned on and the fluorine pump is turned off, the second evaporator needs to output refrigerant to the compressor. Therefore, the second expansion valve needs to control the superheat degree to avoid the phenomenon of liquid hammering of the compressor.

[0016] The technical solution provided by the present disclosure is that when the compressor is turned on and the fluorine pump is turned off, the first bypass pipeline is turned off, the first pipeline is turned off, the second pipeline is turned on, the second expansion valve controls the superheat degree of the refrigerant output by the second evaporator, and the first expansion valve controls the superheat degree of the refrigerant output by the first evaporator, to prevent the first evaporator and the second evaporator from outputting liquid refrigerant and to avoid the phenomenon of liquid hammering of the compressor.

[0017] In an implementation, the inlet of the second evaporator is connected to the outlet of the fluorine pump through a third pipeline, and is also connected to the outlet of the first expansion valve through a fourth pipeline. The first expansion valve is also used to output refrigerant to the second evaporator through the fourth pipeline. Wherein, when the third pipeline is turned on and the fourth pipeline is turned off, the fluorine pump outputs refrigerant to the first expansion valve and the second evaporator respectively, and the circulation loop in which the second evaporator is located does not have an expansion valve. When the third pipeline is turned off and the fourth pipeline is turned on, the refrigerant output by the first bypass pipeline first flows through the first expansion valve, and then flows through the first evaporator and the second evaporator respectively.

[0018] In one implementation, when the compressor and the fluorine pump are both turned on, the third pipeline is turned on and the fourth pipeline is turned off. In this way, the refrigeration system comprises two refrigerant circulation loops. The first circulation loop is compressor-condenser-fluorine pump-first expansion valve-first evaporator-compressor. The second circulation loop is fluorine pump-third pipeline-second evaporator-first pipeline-condenser-fluorine pump. In the second circulation loop, the compressor is not included, and thus, the expansion valve is not needed, and the phenomenon that the fluorine pump pressurizes the refrigerant and then the second expansion valve depressurizes the refrigerant does not occur. In the second circulation loop, the fluorine pump drives the refrigerant to circulate, and the natural cold source is fully utilized, thereby reducing the energy consumption of the refrigeration system and improving the energy efficiency of the refrigeration system.

[0019] In one implementation, when the compressor is turned on and the fluorine pump is turned off, the third pipeline is turned off and the fourth pipeline is turned on. In this way, the refrigerant output by the first bypass pipeline first flows through the first expansion valve, and then flows through the first evaporator and the second evaporator, respectively. The first expansion valve can control the superheat of the refrigerant output by the first evaporator and the second evaporator at the same time, so as to avoid the liquid hammer phenomenon of the compressor. Moreover, only one expansion valve is needed, thereby saving the cost of the expansion valve.

[0020] In one implementation, the refrigeration system further comprises a first bypass pipeline, two ends of the first bypass pipeline being connected to the inlet and the outlet of the compressor, respectively. The first evaporator and the second evaporator are further configured to output the refrigerant to the first bypass pipeline, and the first bypass pipeline is configured to connect the outlet of the first evaporator and the inlet of the condenser, and the outlet of the second evaporator and the inlet of the condenser. When the compressor is turned off, the first bypass pipeline is turned on and bypasses the compressor, so that the refrigerant can normally flow when the compressor is turned off.

[0021] In one implementation, when the compressor and the fluorine pump are both turned on, the first bypass pipeline is turned off, the first pipeline is turned on, and the second pipeline is turned off. When the compressor is turned off and the fluorine pump is turned on, the first bypass pipeline is turned on, the first pipeline is turned off, and the second pipeline is turned on.

[0022] In an implementation, the refrigeration system further comprises a first three-way valve, the first three-way valve comprising a first port, a second port and a third port. The first port is connected to the outlet of the second evaporator, the second port is located in the first pipeline, and the third port is located in the second pipeline. The first three-way valve is used to connect the first port and the second port and separate the first port and the third port to connect the first pipeline and close the second pipeline, or connect the first port and the third port and separate the first port and the second port to close the first pipeline and connect the second pipeline. When the compressor and the fluorine pump are both turned on, the first port and the second port are connected, and the first port and the third port are separated. When the compressor is turned on and the fluorine pump is turned off, the first port and the third port are connected, and the first port and the second port are separated. When the fluorine pump is turned on and the compressor is turned off, the first port and the third port are connected, and the first port and the second port are separated.

[0023] In an implementation, the refrigeration system further comprises a heat dissipation fan, and the air driven by the heat dissipation fan flows through the second evaporator first and then flows through the first evaporator.

[0024] The technical solution provided by the present disclosure can reduce the irreversible loss of heat transfer and improve energy efficiency in the mixed refrigeration mode, because the first evaporator is in the circulation loop where the compressor is located, while the second evaporator is not in the circulation loop where the compressor is located. Therefore, the air driven by the heat dissipation fan is set to flow through the high-temperature second evaporator first and then flow through the low-temperature first evaporator.

[0025] In an implementation, the heat dissipation fan is an air-suction fan, and the second evaporator, the first evaporator and the air-suction side of the heat dissipation fan are arranged in sequence. In this way, the air sucked by the heat dissipation fan flows through the second evaporator and the first evaporator in sequence. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a refrigeration system in a compressor refrigeration mode in the related art;

[0027] Figure 2 is a refrigeration system in a fluorine pump refrigeration mode in the related art;

[0028] Figure 3 is a refrigeration system in a mixed refrigeration mode in the related art;

[0029] Figure 4 is Figure 3 is a pressure-enthalpy diagram of the refrigeration system shown;

[0030] Figure 5 is a refrigeration system in a mixed refrigeration mode provided by an embodiment of the present disclosure;

[0031] Figure 6 is a pressure-enthalpy diagram corresponding to the refrigeration system in the mixed refrigeration mode provided by an embodiment of the present disclosure;

[0032] Figure 7 is a schematic diagram of a refrigeration system provided by an embodiment of the present disclosure;

[0033] Figure 8 is a schematic diagram of another refrigeration system provided by an embodiment of the present disclosure;

[0034] Figure 9 is a schematic diagram of a refrigeration system in the mixed refrigeration mode provided by an embodiment of the present disclosure;

[0035] Figure 10 is a schematic diagram of a refrigeration system in the compressor refrigeration mode provided by an embodiment of the present disclosure;

[0036] Figure 11 is a pressure-enthalpy diagram corresponding to the refrigeration system in the compressor refrigeration mode provided by an embodiment of the present disclosure;

[0037] Figure 12 is a schematic diagram of a fluorine pump refrigeration mode refrigeration system provided by an embodiment of the present disclosure;

[0038] Figure 13 is a pressure-enthalpy diagram corresponding to the refrigeration system in the fluorine pump refrigeration mode provided by an embodiment of the present disclosure;

[0039] Figure 14 is a schematic diagram of another refrigeration system provided by an embodiment of the present disclosure;

[0040] Figure 15 is a schematic diagram of another refrigeration system provided by an embodiment of the present disclosure;

[0041] Figure 16 is a schematic diagram of another refrigeration system in the mixed refrigeration mode provided by an embodiment of the present disclosure;

[0042] Figure 17 is a schematic diagram of another refrigeration system in the compressor refrigeration mode provided by an embodiment of the present disclosure;

[0043] Figure 18 is a schematic diagram of another refrigeration system in the fluorine pump refrigeration mode provided by an embodiment of the present disclosure.

[0044] Legend

[0045] 1, compressor, 2, condenser, 3, fluorine pump, 4, first expansion valve, 5, first evaporator, 6, first bypass pipeline, 7, second bypass pipeline, 8, second evaporator, 9, second expansion valve, 10, first three-way valve, 101, first port, 102, second port, 103, third port, 11, first valve, 12, second valve, 13, second three-way valve, 131, fourth port, 132, fifth port, 133, sixth port, 14, third valve, 15, fourth valve, 16, cooling fan;

[0046] 100, first pipeline, 200, second pipeline, 300, third pipeline, 400, fourth pipeline. DETAILED DESCRIPTION

[0047] The refrigeration system of the machine room of the data center (or referred to as the machine room air conditioner) needs to refrigerate all year round, and therefore, the energy efficiency index of the refrigeration system has become an important index for the construction of the data center.

[0048] Next, the refrigeration system in the related art is exemplarily described. Figure 1 A schematic diagram of the refrigeration system in the related art in a compressor refrigeration mode (i.e., the compressor is turned on and the fluorine pump is turned off) is shown. Figure 2 A schematic diagram of the refrigeration system in the related art in a fluorine pump refrigeration mode (i.e., the compressor is turned off and the fluorine pump is turned on) is shown. The compressor refrigeration mode can also be referred to as a direct expansion refrigeration system (DX) mode.

[0049] As shown in Figure 1 and Figure 2 , the refrigeration system includes a compressor 1, a condenser 2, a fluorine pump 3, a first expansion valve 4 (or referred to as an electronic expansion valve (EEV) or a throttling valve), a first evaporator 5, a first bypass pipeline 6, and a second bypass pipeline 7. The outlet of the compressor 1, the condenser 2, the fluorine pump 3, the first expansion valve 4, the first evaporator 5, and the inlet of the compressor 1 are sequentially communicated. The first bypass pipeline 6 has two ends respectively communicating with the inlet and the outlet of the compressor 1. The second bypass pipeline 7 has two ends respectively communicating with the inlet and the outlet of the fluorine pump 3. The first evaporator 5 is located indoors and is used to cool the indoor environment. The compressor 1, the condenser 2, and the fluorine pump 3 are located outdoors, and the condenser 2 is used to dissipate heat to the outside.

[0050] As shown in Figure 1 , when the outdoor temperature is relatively high (for example, the outdoor temperature > 20℃), the refrigeration system runs in the compressor refrigeration mode. At this time, the compressor 1 is turned on, and the first bypass pipeline 6 is turned off. The fluorine pump 3 is turned off, and the second bypass pipeline 7 is turned on. Next, the compressor refrigeration mode is described in combination with Figure 1The working process of the refrigeration system in compressor refrigeration mode is illustrated by an example.

[0051] AB stage: This stage is completed within compressor 1. Compressor 1 draws in gaseous refrigerant from the first evaporator 5, compresses the gaseous refrigerant, and outputs it as a high-temperature, high-pressure refrigerant.

[0052] Stage BC(D): This stage is completed within condenser 2. Compressor 1 delivers high-temperature, high-pressure refrigerant into condenser 2, where it is cooled and undergoes a change from a gaseous to a liquid state. Simultaneously, the refrigerant transfers heat absorbed indoors to the outside through condenser 2. Since refrigerant pump 3 is not operating, points C and D are equivalent.

[0053] DE stage: This stage is completed at the first expansion valve 4. The function of the first expansion valve 4 is to throttle and reduce pressure, so that the refrigerant becomes a low-pressure, low-temperature state. At the same time, the first expansion valve 4 adjusts its opening based on the temperature at the outlet of the first evaporator 5 to prevent liquid refrigerant from being delivered to the compressor 1, thus avoiding liquid slugging. This adjustment can be simply referred to as superheat regulation.

[0054] EA Stage: This stage is completed within the first evaporator 5. Because the pipe diameter of the first evaporator 5 is much larger than that at the first expansion valve 4, the refrigerant pressure suddenly decreases, and its temperature drops sharply. The cooler refrigerant enters the first evaporator 5, absorbs heat from the room, and becomes a high-temperature, high-pressure state until it completely vaporizes, causing the refrigerant to evaporate rapidly.

[0055] Afterwards, the high-temperature and high-pressure gas in the first evaporator 5 returns to the compressor 1, repeating the above stages and circulating the refrigeration repeatedly.

[0056] like Figure 2 As shown, when the outdoor temperature is low (e.g., outdoor temperature < 10°C), the refrigeration system operates in refrigerant pump cooling mode. At this time, compressor 1 is off, and the first bypass line 6 is open. Refrigerant pump 3 is on, and the second bypass line 7 is off.

[0057] When in refrigerant pump cooling mode, refrigerant pump 3 drives liquid refrigerant to flow through the first evaporator 5. The liquid refrigerant inside the first evaporator 5 absorbs heat from the indoor air, and a small portion of the refrigerant vaporizes. The refrigerant, carrying bubbles, circulates through the first bypass pipe 6 to the condenser 2, where it releases the heat it carries into the outdoor atmosphere. After releasing heat, the refrigerant becomes a subcooled liquid and re-enters refrigerant pump 3. This continuous operation allows for the cooling of indoor air by outdoor cold air.

[0058] Combining the two cooling modes above, it can be seen that when the outdoor temperature is high, compressor 1 provides better cooling, but also consumes more energy. When the outdoor temperature is low, refrigerant pump 3 provides cooling, making full use of the natural cold source and consuming less energy, but it is more sensitive to the outdoor temperature.

[0059] When the outdoor temperature is in a transitional temperature range (e.g., 10℃ < outdoor temperature < 15℃), if the refrigeration system is set to run in refrigerant pump mode, the indoor cooling demand may not be met because the outdoor temperature is not low enough. If the refrigeration system is set to run in compressor mode, while it can meet the indoor cooling demand, it does not utilize available natural cold sources, resulting in higher energy consumption and lower energy efficiency.

[0060] To ensure that the refrigeration system can meet indoor cooling needs while effectively utilizing external natural cold sources in the transition temperature range, one approach is to operate the refrigeration system in a hybrid refrigeration mode. This hybrid refrigeration mode can also be called the refrigerant pump-DX refrigeration mode or the refrigerant pump-compressor refrigeration mode, meaning that both compressor 1 and refrigerant pump 3 are operating.

[0061] Figure 3 A schematic diagram of a refrigeration system in a hybrid refrigeration mode, as shown in the related art, is illustrated. Figure 3 As shown, in the mixed cooling mode, compressor 1 is on, and the first bypass line 6 is off. Refrigerant pump 3 is on, and the second bypass line 7 is off. The refrigerant flows according to... Figure 3 The path shown is a cyclical flow.

[0062] Figure 4 It shows Figure 3 The pressure-enthalpy diagram of the refrigeration system. Combined with... Figure 3 ,as well as, Figure 4 The dashed box shows that in stage C-D, the refrigerant flows through refrigerant pump 3 and is pressurized under its action. In stage DE, the refrigerant flows through the first expansion valve 4, where it is throttled and depressurized, causing a rapid depressurization. Because the refrigerant does not effectively exchange heat with the outside environment during stages C-D-D, but is only pressurized and then depressurized, the pressurization by refrigerant pump 3 actually has no effect, only increasing its power consumption. Therefore, in the related technology, in the hybrid refrigeration mode, the compressor 1 is actually responsible for refrigeration, and the natural cold source is not fully utilized. The purpose of the first expansion valve 4 throttling and depressurizing the refrigerant is to prevent liquid refrigerant from entering the compressor 1, thus avoiding damage to the compressor 1.

[0063] Another approach is to set up two refrigeration systems: one operating in refrigerant pump mode and the other in compressor mode in the transition temperature range. However, this would significantly increase the cost of the refrigeration system.

[0064] In view of the above-mentioned technical problems, this disclosure provides a novel refrigeration system. For example... Figure 5 As shown, the refrigeration system includes a compressor 1, a condenser 2, a refrigerant pump 3, a first expansion valve 4, a first evaporator 5, and a second evaporator 8. The outlet of compressor 1, condenser 2, refrigerant pump 3, first expansion valve 4, first evaporator 5, and compressor 1 inlet are connected sequentially. The inlet of the second evaporator 8 is connected to the outlet of refrigerant pump 3, and the outlet of the second evaporator 8 is connected to the inlet of condenser 2. Specifically, refrigerant pump 3 supplies refrigerant to the first expansion valve 4 and the second evaporator 8. The first expansion valve 4 supplies refrigerant to the first evaporator 5, the first evaporator 5 supplies refrigerant to compressor 1, compressor 1 supplies refrigerant to condenser 2, and the second evaporator 8 supplies refrigerant to condenser 2. Condenser 2 supplies refrigerant to refrigerant pump 3.

[0065] like Figure 5 As shown, in the mixed refrigeration mode, both compressor 1 and refrigerant pump 3 are on. A portion of the refrigerant output from refrigerant pump 3 is sequentially fed into condenser 2 via the first expansion valve 4, the first evaporator 5, and compressor 1; the other portion is fed into condenser 2 via the second evaporator 8. From... Figure 5 As can be seen, in the mixed cooling mode, the refrigeration system includes two refrigerant circulation loops. The first loop is ABCDEA, i.e., compressor 1 - condenser 2 - refrigerant pump 3 - first expansion valve 4 - first evaporator 5 - compressor 1. The second loop is CDBC, i.e., refrigerant pump 3 - second evaporator 8 - condenser 2 - refrigerant pump 3. It is evident that compressor 1 is not included in the second loop, thus eliminating the need for the expansion valve to throttle and reduce pressure, and preventing the phenomenon of refrigerant pump 3 pressurizing the refrigerant only to have it immediately depressurized by the expansion valve. In the second loop, the refrigerant circulation is driven by refrigerant pump 3, fully utilizing the external natural cold source, thereby reducing the energy consumption of the refrigeration system in mixed cooling mode and improving the system's energy efficiency. Furthermore, since compressor 1 is involved in the first loop, it ensures that the cooling capacity of the refrigeration system can meet the indoor demand in mixed cooling mode.

[0066] In other words, the refrigeration system provided by this disclosure can meet the indoor cooling needs in the transition temperature range while effectively utilizing the natural cold source from the outside. Furthermore, only the addition of a second evaporator 8 and other related components is required, without the need for two separate refrigeration systems, thus avoiding excessive costs associated with the refrigeration system.

[0067] Figure 6 It showsFigure 5 The pressure-enthalpy diagram of the refrigeration system. From Figure 6 As can be seen from the diagram, in the CD stage, the refrigerant is pressurized after flowing through the refrigerant pump 3. The pressurized refrigerant then splits into two paths. The first path continues to flow through the first expansion valve 4 and depressurizes (i.e., the DE stage). The second path directly enters the second evaporator 8, depressurizes, and absorbs heat (i.e., the DB stage). Therefore, it is evident that, at least in the DCBD cycle, the refrigerant pressurization by the refrigerant pump 3 is valuable. Thus, it can also be seen from the pressure-enthalpy diagram that the refrigeration system provided in this embodiment effectively utilizes the external natural cold source in the mixed refrigeration mode.

[0068] It should be noted that in the hybrid cooling mode, compressor 1 can adjust the refrigerant flow rate in both circulation loops by adjusting its operating frequency, thus balancing indoor cooling demand with the energy efficiency of the cooling system. For example, when the indoor temperature is high and a larger cooling capacity is needed, compressor 1 increases its operating frequency to increase the flow rate in the ABCDEA circulation loop, thereby increasing the cooling capacity of the cooling system. When the indoor temperature is low and a large cooling capacity is not required, compressor 1 decreases its operating frequency to increase the flow rate in the CDBC circulation loop, thereby improving the utilization rate of external natural cold sources and reducing the energy consumption of the cooling system.

[0069] In some examples, such as Figure 5 As shown, the refrigeration system also includes a first bypass line 6 and a second bypass line 7. The two ends of the first bypass line 6 are connected to the inlet and outlet of the compressor 1, respectively. The two ends of the second bypass line 7 are connected to the inlet and outlet of the refrigerant pump 3, respectively. The first bypass line 6 is equipped with a first check valve or a first bypass valve. The second bypass line 7 is equipped with a second check valve or a second bypass valve. The first bypass line 6 is used to open when the compressor 1 is off, and the second bypass line 7 is used to open when the refrigerant pump 3 is off, thereby ensuring that the refrigerant can circulate in all modes.

[0070] To enable the second evaporator 8 to operate even in compressor refrigeration mode, thereby improving refrigeration efficiency, in some examples, such as... Figure 7-8 and Figure 14-15 As shown, the outlet of the second evaporator 8 is connected to the inlet of the condenser 2 via the first pipe 100, and also to the inlet of the compressor 1 via the second pipe 200. Thus, in the mixed refrigeration mode, the first pipe 100 is open and the second pipe 200 is closed. In the compressor refrigeration mode, the first pipe 100 is closed and the second pipe 200 is open, allowing the refrigerant output from the second evaporator 8 to be supplied to the compressor 1.

[0071] It is understood that, to prevent liquid refrigerant from flowing into compressor 1 and causing liquid slugging, an expansion valve needs to be installed at the inlet of the second evaporator 8. This expansion valve controls superheat based on the outlet temperature of the second evaporator 8. This expansion valve can be a newly added electronic expansion valve or the existing first expansion valve 4. The refrigeration system will now be described in more detail for both scenarios.

[0072] (1) As Figure 7 and Figure 8 As shown, the refrigeration system also includes a second expansion valve 9. The inlet of the second expansion valve 9 is connected to the outlet of the refrigerant pump 3, and the outlet of the second expansion valve 9 is connected to the inlet of the second evaporator 8. The second expansion valve 9 is used to receive refrigerant from the refrigerant pump 3 or the second bypass line 7, and to output refrigerant to the second evaporator 8.

[0073] The following describes the status of each component in the refrigeration system under each refrigeration mode.

[0074] like Figure 9 As shown, in the mixed refrigeration mode, the second expansion valve 9 is fully open, the first pipeline 100 is open, the second pipeline 200 is closed, and the first expansion valve 4 controls superheat based on the outlet temperature of the first evaporator 5. In this mixed refrigeration mode, the refrigeration system includes two loops. The first loop is ABCDEA, i.e., compressor 1 - condenser 2 - refrigerant pump 3 - first expansion valve 4 - first evaporator 5 - compressor 1. The second loop is CDBC, i.e., refrigerant pump 3 - fully open second expansion valve 9 - second evaporator 8 - first pipeline 100 - condenser 2 - refrigerant pump 3. The fully open second expansion valve 9 does not throttle or reduce the pressure of the refrigerant. Figure 9 The pressure-enthalpy diagram of the refrigeration system shown can also be referenced. Figure 6 As shown.

[0075] like Figure 10As shown, in compressor cooling mode, compressor 1 is on, refrigerant pump 3 is off, first bypass line 6 is off, second bypass line 7 is on, first line 100 is off, and second line 200 is on. Second expansion valve 9 controls superheat based on the outlet temperature of second evaporator 8. First expansion valve 4 controls superheat based on the outlet temperature of first evaporator 5. In compressor cooling mode, the refrigerant output from compressor 1 flows sequentially through condenser 2 and second bypass line 7. Then, the refrigerant output from second bypass line 7 is divided into two paths: one flows sequentially through first expansion valve 4 and first evaporator 5 to the inlet of compressor 1, and the other flows sequentially through second expansion valve 9 and second evaporator 8 to the inlet of compressor 1. First expansion valve 4 and second expansion valve 9 control superheat based on the outlet temperatures of first evaporator 5 and second evaporator 8, respectively, to prevent liquid refrigerant from being output from the outlets of first evaporator 5 and second evaporator 8, thus avoiding liquid slugging in compressor 1. Furthermore... Figure 10 The pressure-enthalpy diagram corresponding to the refrigeration system is shown below. Figure 11 As shown.

[0076] like Figure 12 As shown, in refrigerant pump refrigeration mode, compressor 1 is off, and the first bypass line 6 is open. Refrigerant pump 3 is on, and the second bypass line 7 is off. The first line 100 is off, the second line 200 is open, and the first expansion valve 4 and the second expansion valve 9 are fully open. In refrigerant pump refrigeration mode, the refrigerant output from refrigerant pump 3 is divided into two paths: one path flows sequentially through the fully open first expansion valve 4 and the first evaporator 5 into the inlet of the first bypass line 6; the other path flows sequentially through the fully open second expansion valve 9 and the second evaporator 8 into the inlet of the first bypass line 6. The refrigerant in the first bypass line 6 flows into the condenser 2 and then into the refrigerant pump 3. Additionally, Figure 12 The pressure-enthalpy diagram of the refrigeration system is shown below. Figure 13 As shown.

[0077] It should be noted that in the refrigerant pump refrigeration mode, the first line 100 can be opened while the second line 200 is closed. This allows the refrigeration system to operate in refrigerant pump refrigeration mode. Furthermore, in this case, since the branch containing the first evaporator 5 includes the first bypass line 6, while the branch containing the second evaporator 8 does not, to ensure that the flow resistance of the two branches is approximately the same, and thus that the amount of refrigerant passing through the two evaporators is approximately the same, it is necessary to install corresponding components in the branch containing the second evaporator 8 to increase the flow resistance.

[0078] In summary, the control logic of the refrigeration system under each refrigeration mode is shown in Table 1.

[0079] Table 1

[0080]

[0081] In the refrigerant pump refrigeration mode, the status of the first pipe 100 and the second pipe 200 is for reference only and is not unique.

[0082] This disclosure does not limit the implementation method of turning on and off the first pipeline 100 and the second pipeline 200. Two possible implementation methods are provided below.

[0083] In some examples, such as Figure 7 As shown, the refrigeration system also includes a first three-way valve 10, which includes a first port 101, a second port 102, and a third port 103. The first port 101 is connected to the outlet of the second evaporator 8, the second port 102 is located in the first pipe 100, and the third port 103 is located in the second pipe 200. The first three-way valve 10 is used to open the first port 101 and the second port 102, and separate the first port 101 and the third port 103, so as to open the first pipe 100 and close the second pipe 200; or, to open the first port 101 and the third port 103, and separate the first port 101 and the second port 102, so as to close the first pipe 100 and open the second pipe 200.

[0084] Among them, such as Figure 9 As shown, in the hybrid cooling mode, the first port 101 and the second port 102 are connected, while the first port 101 and the third port 103 are separated. Figure 10 As shown, in compressor cooling mode, the first port 101 and the third port 103 are connected, while the first port 101 and the second port 102 are separated. Figure 12 As shown, in the refrigerant pump refrigeration mode, for example, the first port 101 and the third port 103 are connected, and the first port 101 and the second port 102 are separated.

[0085] In other examples, such as Figure 8 As shown, the first pipeline 100 is equipped with a first valve 11, which is used to open or close the first pipeline 100. The second pipeline 200 is equipped with a second valve 12, which is used to open or close the second pipeline 200.

[0086] (2) Figure 14 and Figure 15 As shown, the inlet of the second evaporator 8 is connected to the outlet of the refrigerant pump 3 via a third pipe 300, and also to the outlet of the first expansion valve 4 via a fourth pipe 400. The third pipe 300 and the fourth pipe 400 can be switched on and off.

[0087] The following describes the status of each component in the refrigeration system under each refrigeration mode.

[0088] likeFigure 16 As shown, in the mixed refrigeration mode, both compressor 1 and refrigerant pump 3 are on, and both the first bypass line 6 and the second bypass line 7 are off. The third line 300 is open, and the fourth line 400 is off. The first line 100 is open, and the second line 200 is off. The first expansion valve 4 controls superheat based on the outlet temperature of the first evaporator 5.

[0089] In the hybrid refrigeration mode, the refrigeration system includes two refrigerant circulation loops. The first circulation loop is ABCDEA, namely, compressor 1 - condenser 2 - refrigerant pump 3 - first expansion valve 4 - first evaporator 5 - compressor 1. The second circulation loop is CDBC, namely, refrigerant pump 3 - third line 300 - second evaporator 8 - first line 100 - condenser 2 - refrigerant pump 3. Figure 16 The pressure-enthalpy diagram of the refrigeration system shown can also be referenced. Figure 6 As shown.

[0090] like Figure 17 As shown, in compressor refrigeration mode, compressor 1 is on, refrigerant pump 3 is off, first bypass line 6 is off, and second bypass line 7 is on. Third line 300 is off, and fourth line 400 is on. First line 100 is off, and second line 200 is on. First expansion valve 4 controls superheat based on the outlet temperature of first evaporator 5 and the outlet temperature of second evaporator 8. Figure 17 The pressure-enthalpy diagram of the refrigeration system shown can also be referenced. Figure 11 As shown. Figure 17 As shown, in compressor refrigeration mode, the refrigerant output from compressor 1 flows sequentially through condenser 2, second bypass line 7, and first expansion valve 4. The refrigerant output from first expansion valve 4 is divided into two paths: one flows through first evaporator 5 to the inlet of compressor 1, and the other flows through second evaporator 8 to the inlet of compressor 1. Specifically, first expansion valve 4 performs superheat control based on the outlet temperatures of first evaporator 5 and second evaporator 8 to prevent liquid refrigerant from being output from the outlets of first evaporator 5 and second evaporator 8, thus avoiding liquid slugging in compressor 1.

[0091] like Figure 18 As shown, in refrigerant pump refrigeration mode, compressor 1 is off, refrigerant pump 3 is on, the first bypass line 6 is open, and the second bypass line 7 is closed. The first expansion valve 4 is fully open, the third line 300 is open, and the fourth line 400 is closed. The first line 100 is closed, and the second line 200 is open. Thus, the refrigerant output from refrigerant pump 3 is divided into two paths: one path flows sequentially through the fully open first expansion valve 4 and the first evaporator 5 into the inlet of the first bypass line 6; the other path flows through the second evaporator 8 into the inlet of the first bypass line 6. The refrigerant in the first bypass line 6 flows into the condenser 2 and then into the refrigerant pump 3.

[0092] In other examples, in refrigerant pump refrigeration mode, the third line 300 can be turned off and the fourth line 400 can be turned on.

[0093] In other examples, in refrigerant pump refrigeration mode, the first line 100 can be open and the second line 200 can be closed.

[0094] The second implementation provided in this disclosure does not require increasing the number of expansion valves, which helps reduce the cost of the refrigeration system.

[0095] In summary, the control logic of the refrigeration system under each refrigeration mode is shown in Table 2.

[0096] Table 2

[0097]

[0098] This disclosure does not limit the implementation method of turning on and off the third pipeline 300 and the fourth pipeline 400. Two possible implementation methods are provided below.

[0099] In some examples, such as Figure 14 ,as well as Figure 16-18 As shown, the refrigeration system also includes a second three-way valve 13, which includes a fourth port 131, a fifth port 132, and a sixth port 133. The fourth port 131 connects to the inlet of the second evaporator 8, the fifth port 132 is located in the third pipe 300, and the sixth port 133 is located in the fourth pipe 400. The second three-way valve 13 is used to open the fourth port 131 and the fifth port 132, and to separate the fourth port 131 and the sixth port 133, thereby opening the third pipe 300 and closing the fourth pipe 400. Alternatively, it can open the fourth port 131 and the sixth port 133, and separate the fourth port 131 and the fifth port 132, thereby closing the third pipe 300 and opening the fourth pipe 400.

[0100] Among them, such as Figure 16 As shown, in the hybrid cooling mode, the fourth port 131 and the fifth port 132 are connected, while the fourth port 131 and the sixth port 133 are separated. Figure 17 As shown, in compressor cooling mode, the fourth port 131 and the sixth port 133 are connected, while the fourth port 131 and the fifth port 132 are separated. Figure 18 As shown, in the refrigerant pump cooling mode, exemplary, the fourth port 131 and the fifth port 132 are connected, and the fourth port 131 and the sixth port 133 are separated.

[0101] In other examples, such as Figure 15As shown, the third pipeline 300 is equipped with a third valve 14, which is used to open or close the third pipeline 300. The fourth pipeline 400 is equipped with a fourth valve 15, which is used to open or close the fourth pipeline 400.

[0102] Furthermore, this embodiment does not limit the implementation method of turning on and off the first pipeline 100 and the second pipeline 200 in the second implementation method. For specific implementation methods, please refer to the relevant content above.

[0103] In some examples, such as Figure 5 , Figure 7-10 , Figure 12 or Figure 14-18 As shown, the refrigeration system provided in this embodiment of the present disclosure further includes a cooling fan 16, which drives airflow through the second evaporator 8 and the first evaporator 5 to improve the heat exchange efficiency between the evaporator and the indoor air.

[0104] Understandably, in the hybrid cooling mode, since the first evaporator 5 is in the same circulation loop as the compressor 1, while the second evaporator 8 is not, the temperature of the second evaporator 8 is generally higher than that of the first evaporator 5. Therefore, the air driven by the cooling fan 16 can be configured to flow through the second evaporator 8 first, and then through the first evaporator 5. That is, it flows through the high-temperature evaporator first, and then through the low-temperature evaporator, to reduce irreversible heat transfer losses and improve energy efficiency. However, it is understandable that if the air flows through the low-temperature evaporator first, and then through the high-temperature evaporator, it is possible that the air will be cooled by the low-temperature evaporator and then reheated by the high-temperature evaporator.

[0105] In some examples, the cooling fan 16 is an intake fan, in which case the second evaporator 8, the first evaporator 5, and the intake side of the cooling fan 16 are arranged in sequence. The air drawn in by the cooling fan 16 flows sequentially through the second evaporator 8 and the first evaporator 5.

[0106] In other examples, the cooling fan 16 is a blower fan, in which case the exhaust side of the cooling fan 16, the second evaporator 8, and the first evaporator 5 are arranged in sequence. The air blown out by the cooling fan 16 flows sequentially through the second evaporator 8 and the first evaporator 5.

[0107] Alternatively, the first evaporator 5 and the second evaporator 8 can be two independent evaporators or integrated into the same evaporator. For example, the evaporator may contain two separate evaporation tubes, which form the first evaporator 5 and the second evaporator 8, respectively.

[0108] In practical applications, by adopting the technical solutions provided in the embodiments of this disclosure, system energy efficiency can be improved, reducing the annual cooling load factor (CLF) of data centers by 10% to 20%. CLF is an indicator that measures the energy efficiency of a data center cooling system; it represents the ratio of power consumption of cooling equipment to power consumption of internet technology (IT) in the data center. The formula for calculating CLF is: CLF = Power consumption of cooling equipment / Total energy consumption of IT equipment.

[0109] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A refrigeration system characterized by, The refrigeration system comprises a compressor (1), a condenser (2), a fluorine pump (3), a first expansion valve (4), a first evaporator (5) and a second evaporator (8); The fluorine pump (3) is used for outputting refrigerant to the first expansion valve (4) and the second evaporator (8); the first expansion valve (4) is used for outputting refrigerant to the first evaporator (5), the first evaporator (5) is used for outputting refrigerant to the compressor (1), and the compressor (1) is used for outputting refrigerant to the condenser (2); the second evaporator (8) is used for outputting refrigerant to the condenser (2); and the condenser (2) is used for outputting refrigerant to the fluorine pump (3).

2. The refrigeration system of claim 1, wherein, The outlet of the second evaporator (8) is connected to the inlet of the condenser (2) through a first pipeline (100), and is also connected to the inlet of the compressor (1) through a second pipeline (200); The second evaporator (8) is used for outputting refrigerant to the condenser (2) through the first pipeline (100), or outputting refrigerant to the compressor (1) through the second pipeline (200).

3. The refrigeration system of claim 2, wherein, The refrigeration system further comprises a second bypass pipeline (7), and the two ends of the second bypass pipeline (7) are connected to the inlet and outlet of the fluorine pump (3) respectively; The condenser (2) is also used for outputting refrigerant to the second bypass pipeline (7), the second bypass pipeline (7) is used for connecting the outlet of the condenser (2) to the first expansion valve (4) and the second evaporator (8), and the condenser (2) is used for outputting refrigerant to the second bypass pipeline (7).

4. The refrigeration system of claim 3, wherein, When the compressor (1) and the fluorine pump (3) are both turned on, the second bypass pipeline (7) is turned off, the first pipeline (100) is turned on, and the second pipeline (200) is turned off; When the compressor (1) is turned on and the fluorine pump (3) is turned off, the second bypass pipeline (7) is turned on, the first pipeline (100) is turned off, and the second pipeline (200) is turned on.

5. The refrigeration system of claim 3 or 4, wherein, The refrigeration system further comprises a second expansion valve (9), which is used for receiving refrigerant output by the fluorine pump (3) or the second bypass pipeline (7) and outputting refrigerant to the second evaporator (8).

6. The refrigeration system of claim 5, wherein, When the compressor (1) and the fluorine pump (3) are both turned on, the second expansion valve (9) is fully opened.

7. The refrigeration system of claim 3 or 4, wherein, The inlet of the second evaporator (8) is connected to the outlet of the fluorine pump (3) through a third pipeline (300), and is also connected to the outlet of the first expansion valve (4) through a fourth pipeline (400); The first expansion valve (4) is also used for outputting refrigerant to the second evaporator (8) through the fourth pipeline (400).

8. The refrigeration system of claim 7, wherein, When the compressor (1) and the fluorine pump (3) are both turned on, the third pipeline (300) is turned on, and the fourth pipeline (400) is turned off; When the compressor (1) is turned on and the fluorine pump (3) is turned off, the third pipeline (300) is turned off, and the fourth pipeline (400) is turned on.

9. The refrigeration system of any of claims 2-8, wherein, The refrigeration system further comprises a first bypass pipeline (6), two ends of the first bypass pipeline (6) are communicated with the inlet and outlet of the compressor (1) respectively; The first evaporator (5) and the second evaporator (8) are further used for outputting refrigerant to the first bypass pipeline (6), the first bypass pipeline (6) is used for connecting the outlet of the first evaporator (5) and the inlet of the condenser (2), and the outlet of the second evaporator (8) and the inlet of the condenser (2).

10. The refrigeration system of claim 9, wherein, When the compressor (1) and the fluorine pump (3) are both opened, the first bypass pipeline (6) is closed, the first pipeline (100) is connected, and the second pipeline (200) is closed; When the compressor (1) is closed and the fluorine pump (3) is opened, the first bypass pipeline (6) is connected, the first pipeline (100) is closed, and the second pipeline (200) is connected.

11. The refrigeration system of any of claims 2-10, wherein, The refrigeration system further comprises a first three-way valve (10), the first three-way valve (10) comprises a first port (101), a second port (102) and a third port (103), the first port (101) is communicated with the outlet of the second evaporator (8), the second port (102) is located in the first pipeline (100), and the third port (103) is located in the second pipeline (200); The first three-way valve (10) is used for connecting the first port (101) and the second port (102), separating the first port (101) and the third port (103), so as to connect the first pipeline (100) and close the second pipeline (200); or connecting the first port (101) and the third port (103), separating the first port (101) and the second port (102), so as to close the first pipeline (100) and connect the second pipeline (200).

12. The refrigeration system of any of claims 1-11, wherein, The refrigeration system further comprises a heat dissipation fan (16), the heat dissipation fan (16) drives the air to flow through the second evaporator (8) first and then flow through the first evaporator (5).

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