WO2016141792A1

WO2016141792A1 - Multi-connection refrigeration system and control method thereof

Info

Publication number: WO2016141792A1
Application number: PCT/CN2016/073230
Authority: WO
Inventors: 黄志超; 黄桂良; 胡荣国
Original assignee: 深圳市艾特网能有限公司
Priority date: 2015-03-10
Filing date: 2016-02-02
Publication date: 2016-09-15
Also published as: CN104896630B; CN104896630A

Abstract

A multi-connection refrigeration system, comprising at least one indoor refrigerating unit (10), at least one outdoor refrigerating unit (20), and a cold energy transfer unit (30) connecting the indoor refrigerating unit (10) to the outdoor refrigerating unit (20). The cold energy transfer unit (30) comprises a liquid storage device (31) for storing a phase-change refrigerant, and a transporting pump (32) connected to the liquid storage device (31). The outdoor refrigerating unit (20) comprises a recuperative heat exchanging unit (21) comprising a first heat exchanging pipe (211) and a second heat exchanging pipe (212) independent of each other and used to exchange heat. The outdoor refrigerating unit (20) further comprises a compressor (22), a condensing device (23), a second flow control valve (24) and a second control portion (25). The indoor refrigerating unit (10) comprises a first flow control valve (11), an indoor evaporator (12) and a first control portion (13). The indoor refrigerating unit (10), the cold energy transfer unit (30) and the first heat exchanging pipe (211) form a closed cycle. Also provided is a control method of the multi-connection refrigeration system. The multi-connection refrigeration system and the control method enable a high heat exchange efficiency, have a simple structure and a convenient and simple system control process, and effectively reduce energy waste.

Description

Description: Inventive name: Multi-connected refrigeration system and its control method

[0001] The present invention relates to the field of refrigeration systems, and in particular, to a multiple refrigeration system and a control method thereof.

Background technique

[0002] Current multi-unit refrigeration systems, especially in multi-unit refrigeration units such as computer rooms and data centers, such as air-cooled chillers and water-cooled chillers, are transported by chilled water or ethylene glycol. The refrigerant delivery cooling capacity has the following outstanding problems: First, more refrigerant is required; second, the higher demand refrigerant circulation amount corresponds to the higher refrigerant delivery pump power; Third, the heat exchange efficiency is low. Moreover, in the current refrigeration system, the indoor unit has a large volume, low efficiency, and low energy efficiency ratio. As the requirements of national energy conservation and emission reduction policies become higher and higher, improving efficiency and conserving resources have become an important direction for the development of refrigeration systems.

[0003] For example, in the current multi-connected refrigeration system, the circulating water volume of chilled water needs to reach 17.2 tons/min in units of chilled water with a cooling capacity of 21 kJ and 100 kW per kW of temperature difference of 5 degrees; According to the calculation of the conventional unit, the power of the pump needs to reach more than 10 kW.

technical problem

The technical problem to be solved by the present invention is to provide an improved multiple cooling system and a control method thereof against the defects of the prior art.

Problem solution

Technical solution

[0005] The technical solution adopted by the present invention to solve the technical problem thereof is: a multiple refrigeration system including at least one indoor refrigeration unit, at least one outdoor refrigeration unit, and for connecting the indoor refrigeration unit and the outdoor refrigeration Cooling unit of the unit;

[0006] The cold conveying unit includes a liquid storage device for storing a phase change refrigerant and a transfer pump connected to the liquid storage device;

[0007] The outdoor refrigeration unit includes a partition wall heat exchange unit, and the partition wall heat exchange unit includes mutually independent first heat exchange tubes and second heat exchange tubes for performing heat exchange; Said The cold conveying unit and the first heat exchange conduit form a closed loop;

[0008] the indoor refrigeration unit includes a first flow control valve connected to the delivery pump outlet, an indoor evaporator connected to the first flow control valve outlet and the first heat exchange conduit inlet, and a first a control unit, wherein the first control unit is respectively connected to the first flow control valve and the transfer pump, and is configured to control start and stop of the first flow control valve and the transfer pump according to indoor cooling demand, according to The indoor outlet superheat of the indoor evaporator controls the temperature of the first flow control valve, and the capacity output of the transfer pump is controlled according to a pressure difference before and after the transfer pump;

[0009] The outdoor refrigeration unit further includes a compressor connected to the second heat exchange conduit outlet, a condensing device connected to the compressor outlet, and the condensing device outlet and the second heat exchange conduit inlet a second flow control valve and a second control unit connected to the compressor, the second flow control valve and the condensing device, respectively, for controlling the compression according to an outdoor cooling demand Start/stop or capacity output of the machine, controlling the capacity output of the condensing device according to the first outlet pressure of the outlet of the condensing device and/or the first outlet temperature, and controlling the superheat of the outdoor outlet according to the second heat exchange pipe The second flow control valve has a twist.

[0010] Preferably, the at least one indoor refrigeration unit comprises at least two indoor refrigeration units arranged in parallel.

[0011] Preferably, the method further includes an indoor fan that cooperates with the indoor evaporator, and the first control unit is connected to the indoor fan, and is configured to control the intensity or capacity output of the indoor fan according to the indoor cooling demand.

[0012] Preferably, the outdoor refrigeration unit comprises at least two outdoor refrigeration units arranged in series, and the first heat exchange pipes of the at least two outdoor refrigeration units are connected;

[0013] or

[0014] the outdoor refrigeration unit includes at least two outdoor refrigeration units arranged in parallel, the at least two outdoor refrigeration units sharing one of the partition wall heat exchange units and one of the second flow control valves, the at least two At least two compressors of the outdoor refrigeration unit are connected in parallel to the second heat exchange conduit outlet of the partition wall heat exchange unit, and at least two condensation devices are connected in parallel to the at least two compressor outlets and the second flow Control valve inlet;

[0015] or

[0016] The outdoor refrigeration unit includes at least two outdoor refrigeration units arranged in parallel, and the first heat exchange conduit outlets of the at least two outdoor refrigeration units are respectively connected to the liquid storage device. [0017] Preferably, the condensing device includes an outdoor fan connected to the outdoor condenser connected between the compressor and the second flow control valve, and the outdoor fan, the second control unit and the The outdoor fan is connected to control a capacity output of the outdoor fan according to a first outlet pressure and/or a first outlet temperature of the outdoor condenser outlet;

[0018] or

[0019] the condensing device includes an outdoor condenser connected between the compressor and the second flow control valve, and a cooling water output device coupled to the outdoor condenser, the second control unit controlling the The capacity output of the cooling water output device.

[0020] The present invention also provides a control method of a multiple refrigeration system, including the following steps performed by the first control unit

[0021] S11: obtaining indoor refrigeration demand, indoor outlet superheat of the indoor evaporator, and a pressure difference value before and after the pump;

[0022] S12: controlling start and stop of the first flow control valve and the transfer pump according to indoor refrigeration demand;

[0023] S13: controlling the twist of the first flow control valve according to the indoor outlet superheat of the indoor evaporator;

[0024] S14: controlling the capacity output of the transfer pump according to a pressure difference before and after the transfer pump;

[0025] further comprising the following steps performed by the second control unit:

[21] S21: determining an outdoor cooling demand, a first outlet pressure of the condensing device outlet and/or a first outlet temperature, and an outdoor outlet superheat of the second heat exchange conduit;

[0027] S22: controlling start/stop or capacity output of the compressor according to an outdoor cooling demand;

[0028] S23: controlling a capacity output of the condensing device according to a first outlet pressure and/or a first outlet temperature of the outlet of the condensing device;

[0029] S24: controlling the twist of the second flow control valve according to the outdoor outlet superheat of the second heat exchange conduit

[0030] Preferably, the step S11 includes: collecting an indoor ambient temperature, comparing the indoor ambient temperature with a first preset temperature value, calculating a temperature difference between the two to determine the indoor cooling demand; Calculating a second outlet temperature of the evaporator outlet and/or a second outlet pressure to determine the indoor outlet superheat; collecting a pump inlet pressure and a pump outlet pressure of the delivery pump, and calculating a pressure difference before and after the pump is obtained value. [0031] Preferably, the step S12 includes: comparing the indoor cooling demand with a preset first cooling threshold, and if the indoor cooling demand is greater than or equal to the first cooling threshold, controlling the first The flow control valve and the delivery pump are activated, and if not, controlling the first flow control valve and the delivery pump to stop working;

[0032] and / or

[0033] The step S13 includes: comparing the indoor outlet superheat degree with a preset first superheat degree threshold range, and if the indoor outlet superheat degree is less than the first superheat degree threshold range, reducing the Determining the temperature of the first flow control valve; if the indoor outlet superheat is greater than the first superheat threshold range, increasing the twist of the first flow control valve; if the indoor outlet superheat is at Maintaining the temperature of the first flow control valve within the first superheat threshold range;

[0034] and / or

[0035] the step S14 includes: comparing the pressure difference value with a preset pressure difference threshold range, and if the pressure difference value is less than the pressure difference threshold range, reducing a capacity output of the delivery pump; And the pressure difference value is greater than the pressure difference threshold range, thereby increasing the capacity output of the delivery pump; if the pressure difference value is within the pressure difference threshold range, maintaining the capacity output of the delivery pump.

[0036] Preferably, the step S21 includes: collecting a third outlet temperature, a third outlet pressure, a first inlet pressure or a first inlet temperature of the first heat exchange conduit outlet, and the third outlet temperature, Calculating the three outlet pressures, the first inlet pressure or the first inlet temperature and the second preset temperature value to obtain the outdoor refrigeration demand; collecting the fourth outlet temperature and/or the fourth outlet pressure of the second heat exchange conduit outlet Calculated to determine the outdoor outlet superheat

[0037] Preferably, the step S22 includes: comparing the outdoor cooling demand with a preset second cooling threshold, and if the outdoor cooling demand is greater than the second cooling threshold, controlling the starting the compression And adjusting the capacity output of the compressor, and if not, controlling the compressor to stop working;

[0038] and / or

[0039] the step S23 includes: converting the first outlet temperature into a corresponding outlet pressure value by calculation, and performing the corresponding outlet pressure value or the first outlet pressure with a preset pressure threshold range. Comparing; if the corresponding outlet pressure value or the first outlet pressure is greater than the pressure threshold range, increasing a capacity output of the condensing device; if the corresponding outlet pressure value or the first outlet pressure small Reducing the capacity output of the condensing device within the pressure threshold range; maintaining the capacity of the condensing device if the corresponding outlet pressure value or the first outlet pressure is within the pressure threshold range Output

[0040] and / or

[0041] The step S24 includes: comparing the outdoor outlet superheat degree with a preset second superheat degree threshold range, and if the outdoor outlet superheat degree is less than the second superheat degree threshold range, reducing the The second flow control valve has a twist; if the outdoor outlet superheat is greater than the second superheat threshold range, increasing the twist of the second flow control valve; if the outdoor outlet superheat is Within the second superheat threshold range, the temperature of the second flow control valve is maintained.

Advantageous effects of the invention

Beneficial effect

Compared with the prior art, the present invention has the following advantages: The cold conveying unit of the multiple refrigeration system provided by the present invention delivers a phase change refrigerant as a cooling capacity, and has high heat exchange efficiency and required refrigerant circulation. The utility model has the advantages of low volume and no need for a higher power transfer pump; moreover, the partition wall heat exchange unit adopts the invention, and has the advantages of high heat exchange efficiency, small heat loss, compact structure and light weight, and small floor space; The indoor refrigeration unit includes only the indoor evaporator and the first flow control valve and the first control portion, and the volume thereof is small.

[0043] The control method of the multiple refrigeration system provided by the present invention, the first control unit obtains the indoor refrigeration demand, the indoor outlet superheat and the pressure difference before and after the pump, and independently controls the first flow control valve and the conveying The second control unit obtains the outdoor cooling demand, the first outlet pressure of the condensing device outlet, and/or the first outlet temperature and the outdoor outlet superheat, and independently controls the compressor, the condensing device and the second flow control valve. The control method of the multiple refrigeration system is simple and easy to implement, and the corresponding components of the multiple refrigeration system are independently controlled to avoid energy waste caused by the associated control of multiple components.

Brief description of the drawing

DRAWINGS

[0044] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a schematic structural view of a multiple refrigeration system in Embodiment 1 of the present invention.

2 is another schematic structural view of a multiple refrigeration system in Embodiment 1 of the present invention.

3 is another schematic structural view of a multiple refrigeration system in Embodiment 1 of the present invention. 4 is another schematic structural view of a multiple refrigeration system in Embodiment 1 of the present invention.

5 is a flow chart showing a control method of the multiple refrigeration system in Embodiment 2 of the present invention.

6 is a flow chart of step S12 of FIG. 5.

7 is a flow chart of step S13 of FIG. 5.

8 is a flow chart of step S14 of FIG. 5.

9 is a flow chart of step S22 of FIG. 5.

10 is a flow chart of step S23 of FIG. 5.

11 is a flow chart of step S24 of FIG. 5.

[0056] In the figure: 10, indoor refrigeration unit; 11, the first flow control valve; 12, indoor evaporator; 13, the first control unit; 14, indoor fan; 15, the first stop valve; 20; outdoor refrigeration unit; 21, wall-type heat exchange unit; 211, first heat exchange pipe; 212, second heat exchange pipe; 22, compressor; 23, condensing device; 231, outdoor condenser; Outdoor fan; 233, cooling water output device; 24, second flow control valve; 25, second control unit; 30, cold conveying unit; 31, liquid storage device; 32, conveying pump.

Embodiments of the invention

[0057] In order to more clearly understand the technical features, objects and effects of the present invention, the embodiments of the present invention are described in detail with reference to the accompanying drawings.

Embodiment 1

1 to 4 show a multiple refrigeration system in the present embodiment, the multiple refrigeration system including at least one indoor refrigeration unit 10, at least one outdoor refrigeration unit 20, and for connecting the indoor refrigeration unit 10 and the outdoor Cooling unit 30 of refrigeration unit 20. Specifically, at least one indoor refrigeration unit 10 includes at least two indoor refrigeration units 10 arranged in parallel. It can be understood that at least two indoor refrigeration units 10 are arranged in parallel such that the indoor refrigeration units 10 do not affect each other; the number of each indoor refrigeration unit 10 is determined according to user requirements, and the number of outdoor refrigeration units 20 depends on the indoor refrigeration unit. 10 required cooling requirements are determined.

As shown in FIGS. 1-4, the cooling amount delivery unit 30 includes a liquid storage device 31 for storing phase change refrigerant and a transfer pump 32 connected to the liquid storage device 31. The phase change refrigerant may be a liquid phase change refrigerant such as Freon, which absorbs heat (i.e., refrigeration capacity) into the chamber during evaporation in a low temperature state. Understandably, phase change The refrigerant utilizes the principle of liquid evaporation and heat absorption. Compared with the cooling water in the air-cooled or water-cooled unit, the heat exchange efficiency is higher, and the required refrigerant circulation is lower, and no higher power is required. Delivery pump 32. Experiments have shown that the phase change refrigerant is used to transport the cooling capacity, and the unit with a cooling capacity of 214 kJ and 100 kW per kilogram can only reach 1.687 ton / 吋 of the refrigerant, and the power of the pump 32 is only Need l.lkW.

[0061] As shown in FIG. 1 to FIG. 3, the outdoor refrigeration unit 20 includes a partition wall heat exchange unit 21, and the partition wall heat exchange unit 21 includes mutually independent first heat exchange tubes 211 and second exchanges for performing heat exchange. Heat pipe 212. It can be understood that the partition wall heat exchange unit 21 can be a plate heat exchange unit, and the plate heat exchange unit is an important device for heat exchange between liquid-liquid and liquid-vapor, and has high heat exchange efficiency, small heat loss, compact structure and light weight. The utility model has the advantages of small occupied area, convenient installation and cleaning, wide application and long service life.

[0062] As shown in FIGS. 1 to 4, the indoor refrigeration unit 10, the cold delivery unit 30, and the first heat exchange conduit 211 form a closed cycle. Specifically, the indoor refrigeration unit 10 includes a first flow control feed 1 connected to the outlet of the transfer pump 32, an indoor evaporator 12 connected to the outlet of the first flow control valve 11 and the inlet of the first heat exchange conduit 211, and a first control unit. 13. The first control unit 13 is connected to the first flow control valve 11 and the transfer pump 32, respectively, for controlling the start and stop of the first flow control valve 11 and the transfer pump 32 according to the indoor refrigeration demand, according to the indoor outlet of the indoor evaporator 12 The heat controls the temperature of the first flow control valve 11, and controls the capacity output of the transfer pump 32 based on the differential pressure before and after the transfer pump 32.

[0063] It can be understood that the liquid phase change refrigerant stored in the liquid storage device 31 is transported to the indoor evaporator 12 by the transfer pump 32, and the vaporized heat transfer is converted into a vapor phase by the indoor evaporator 12. The refrigerant is changed to provide a cooling capacity that meets the user's demand; the vapor phase change refrigerant flows through the first heat exchange conduit 211 of the partition heat exchange unit 21, and passes through the first heat exchange conduit 211 and the second heat exchange conduit 212. Heat exchange is performed to convert the vapor phase change refrigerant into a liquid phase change refrigerant and deliver it to the liquid storage device 31.

[0064] As shown in FIG. 1 to FIG. 4, the indoor refrigeration unit 10 further includes an indoor fan 14 that cooperates with the indoor evaporator 12, and the first control unit 13 is connected to the indoor fan 14 for controlling the indoor fan 14 according to the indoor refrigeration demand. The strength or capacity output. It is understood that the indoor fan 14 cooperating with the indoor evaporator 12 is used to increase the evaporation efficiency of the indoor evaporator 12, thereby improving the heat exchange efficiency of the indoor refrigeration unit 10.

[0065] It can be understood that the indoor refrigeration unit 10 further includes a first shutoff valve 15 disposed at the inlet of the first flow control valve 11 and a second shutoff valve 16 at the outlet of the indoor evaporator 12 (as shown in FIGS. 1-4). Through the first stop valve 1 The arrangement of the fifth and second shut-off valves 16 facilitates independent control of any indoor refrigeration unit 10 to access the multiple refrigeration system to better meet the user's needs.

[0066] The outdoor refrigeration unit 20 further includes a compressor 22 connected to the outlet of the second heat exchange conduit 212, a condensing device 23 connected to the outlet of the compressor 22, and an inlet connected to the outlet of the condensing device 23 and the inlet of the second heat exchange conduit 212. The second flow control valve 24 and the second control unit 25 are connected to the compressor 22, the second flow control valve 24 and the condensing device 23, respectively, for controlling the start-stop or capacity of the compressor 22 according to the outdoor cooling demand. Output, controlling the capacity output of the condensing device 23 according to the first outlet pressure of the outlet of the condensing device 23 and/or the first outlet temperature, and controlling the twist of the second flow control valve 24 according to the outdoor outlet superheat of the second heat exchange conduit 212 .

[0067] It can be understood that the vaporous refrigerant placed in the circulation pipe of the outdoor refrigeration unit 20 is exothermic under the condensation of the compressor 22 and the condensing device 23 and converted into a liquid refrigerant, and the liquid refrigerant is in the partition heat exchange unit 21. The second heat exchange tube 212 absorbs heat to perform liquid to vapor phase conversion, and outputs vapor refrigerant to the compressor 22 and the condensing unit 23. It can be understood that the first heat exchange conduit 211 and the second heat exchange conduit 21 of the partition wall heat exchange unit 21 respectively perform vapor-liquid conversion and liquid-vapor conversion, and the heat exchange efficiency is high and the heat loss is small.

As shown in FIG. 1 to FIG. 4, the first control unit 13 is in communication with the second control unit 25, and the second control unit 25 controls the activation of the second control unit 25 based on the indoor cooling demand transmitted by the first control unit 13. Stopping, that is, the first control unit 13 actually detects the indoor cooling demand to control the start and stop of the first flow control valve 11 and the transfer pump 32. If the first flow control valve 11 and the transfer pump 32 start and stop, the second control is correspondingly controlled. The control unit 25 is activated to detect the outdoor cooling demand, the first outlet pressure of the outlet of the condensing device 23 and/or the first outlet temperature, and the outdoor outlet superheat of the second heat exchange conduit 212 to control the respective compressors 22, condensing Device 23 and second flow control valve 24

[0069] It can be understood that the condensing device 23 disposed outdoors can adopt an air-cooling unit (as shown in FIG. 1 to FIG. 3).

The condensing device 23 includes an outdoor fan 232 coupled to the outdoor condenser 231 connected between the compressor 22 and the second flow control valve 24, and the second control unit 25 is connected to the outdoor fan 232 for The first outlet pressure at the outlet of the outdoor condenser 231 and/or the first outlet temperature controls the capacity output of the outdoor fan 232.

[0070] It can be understood that the condensing device 23 placed outdoors can also adopt a water cooling unit (as shown in FIG. 4), and the condensing unit 23 includes an outdoor condenser connected between the compressor 22 and the second flow control valve 24. 231 and with The cooling water output device 233 that the outdoor condenser 231 is engaged with, the second control unit 25 controls the capacity output of the cooling water output device 2 33.

[0071] As shown in FIG. 1, the outdoor refrigeration unit 20 may include at least two outdoor refrigeration units 20 arranged in series, and the first heat exchange tubes 211 of at least two outdoor refrigeration units 20 are connected to flow through at least two second The phase change refrigerant of the heat exchange pipe 212 is subjected to multi-stage condensation to make the condensation efficiency better, thereby improving the heat exchange efficiency of the multiple refrigeration system.

[0072] As shown in FIG. 2, the outdoor refrigeration unit 20 may include at least two outdoor refrigeration units 20 arranged in parallel, and at least two outdoor refrigeration units 20 share a wall heat exchange unit 21 and a second flow control valve 24, At least two compressors 22 of at least two outdoor refrigeration units 20 are connected in parallel to the second heat exchange conduit 2 12 outlet of the heat exchange unit, and at least two condensing devices 23 are connected in parallel to at least two compressor 22 outlets and a second flow Control valve 24 inlet. At least two outdoor refrigerating units 20 are respectively arranged in parallel by the compressor 22 and the condensing device 23 as shown in FIG. 2, which can effectively accelerate the condensation efficiency of the outdoor refrigerating unit 20, thereby accelerating the evaporation efficiency in the second heat exchange conduit 212. , improving heat exchange efficiency of the second heat exchange pipe 212 and the first heat exchange pipe 211

As shown in FIG. 3, the outdoor refrigeration unit 20 includes at least two outdoor refrigeration units 20 arranged in parallel, and the outlets of the first heat exchange tubes 211 of the at least two outdoor refrigeration units 20 are connected to the respective liquid storage devices 31. It can be understood that at least two outdoor refrigeration units 20 adopt a connection manner as shown in FIG. 3, so that each outdoor refrigeration unit 20 exchanges heat with at least two outdoor refrigeration units 20 without affecting each other, and ensures each outdoor refrigeration unit. 20 heat exchange efficiency with at least two indoor refrigeration units 10.

Example 2

[0075] FIG. 5 shows a control method of the multiple refrigeration system in the present embodiment, the control method including the following steps performed by the first control unit 13:

[0076] S11: The first control unit 13 actually acquires the indoor cooling demand CFrl, the indoor outlet superheat degree SHrl of the indoor evaporator 12, and the differential pressure ΔΡ before and after the transfer pump 32. Specifically, the step S11 includes: acquiring the indoor cooling demand C Frl by collecting the indoor ambient temperature T1, comparing the indoor ambient temperature T1 with the first preset temperature value Ts etl, and calculating the temperature difference between the two as the indoor cooling demand CFrl . The indoor outlet superheat degree SHrl of the indoor evaporator 12 is determined by collecting the second outlet temperature T2 and/or the second outlet pressure P1 at the outlet of the indoor evaporator 12, and calculating according to the superheat degree calculation formula to determine the indoor outlet of the indoor evaporator 12. Over Heat SHrl. Specifically, by collecting the second outlet temperature T2 at two points of the outlet of the indoor evaporator 12, or the second outlet pressure P1 of two points, or collecting the second outlet temperature Τ2 and the second outlet pressure PI at any point, The indoor outlet superheat degree SHrl of the indoor evaporator 12 is calculated. The determination of the pressure difference ΔP before and after the delivery pump 32 is performed by collecting the pump inlet pressure P2 and the pump outlet pressure P3 of the delivery pump 32, and calculating the pressure difference ΔΡ before and after the delivery pump 32 is obtained.

[0077] S12: The first control unit 13 controls the start and stop of the first flow control valve 11 and the transfer pump 32 according to the indoor cooling demand CFrl. As shown in FIG. 6, step S12 includes the following steps: First control unit 13 compares indoor cooling demand CFrl with preset first cooling threshold CFsetl, and if indoor cooling demand CFrl is greater than or equal to first cooling threshold CFset1, then control A flow control valve 11 and a transfer pump 32 are activated, and if not, the first flow control valve 11 and the transfer pump 32 are controlled to stop operating. That is, only if the calculated indoor cooling demand CFrl is greater than the second cooling enthalpy CFsetl吋, it is necessary to control the indoor refrigeration unit 10 to cool, and then control the first flow control valve 11 and the transfer pump 32 to start; the larger the indoor refrigeration demand CFrl, indicating that The greater the cooling output requirement, the greater the torque Xrl of the first flow control valve 11 and the capacity output of the delivery pump 32 need to be adjusted accordingly.

[0078] and / or

[1379] S13: The first control unit 13 controls the twist Xrl of the first flow control valve 11 in accordance with the indoor outlet superheat degree SHrl of the indoor evaporator 12. As shown in FIG. 7, step S13 includes the following steps: The first control unit 13 compares the indoor outlet superheat degree SHrl with a preset first superheat degree threshold range SHsetl, if the indoor outlet superheat degree SHrl is smaller than the first superheat degree threshold range SHsetl Then, the twist Xrl of the first flow control valve 11 is reduced. If the indoor outlet superheat degree SHrl is greater than the first superheat degree threshold range SHset1, the twist Xrl of the first flow control valve 11 is increased. If the indoor outlet superheat degree SHrl is within the first superheat threshold range SHset1, the twist Xrl of the first flow control valve 11 is maintained.

[0080] and / or

[0081] S14: The first control unit 13 controls the capacity output of the transfer pump 32 based on the differential pressure ΔΡ before and after the transfer pump 32. As shown in FIG. 8, step S14 includes: the first control unit 13 compares the differential pressure difference ΔΡ with a preset differential pressure threshold range Pset, and reduces the capacity of the transfer pump 32 if the differential pressure difference ΔΡ is smaller than the differential pressure threshold range Pset. Output. If the differential pressure ΔΡ is greater than the differential pressure threshold range Pset, the capacity output of the transfer pump 32 is increased; if the differential pressure ΔΡ is within the differential pressure threshold range Pset, the capacity output of the transfer pump 32 is maintained.

[0082] It can be understood that the first control unit 13 does not affect the mutual control of the transfer pump 32 and the first flow control valve 11. Ringing, that is, there is no order between the two, independent control according to their respective control conditions. Specifically, the first control unit 13 controls the transfer pump 32 and the first flow control valve 11 by using a PID control method or a P control method.

[0083] The control method of the multiple refrigeration system further includes the following steps performed by the second control unit 25:

[0084] S21: determining an outdoor cooling demand CFr2, a first outlet pressure P4 of the outlet of the condensing unit 23, and/or a first outlet temperature T3, and an outdoor outlet superheat degree SHr2 of the second heat exchange conduit 212.

[0085] The step S21 includes: the outdoor cooling demand CFr2 collects the third outlet temperature T4, the third outlet pressure Ρ5, the first inlet pressure Ρ6 or the first inlet temperature Τ5 of the outlet of the first heat exchange conduit 211, and The three outlet temperature Τ4, the third outlet pressure Ρ5, the first inlet pressure Ρ6 or the first inlet temperature Τ6 are calculated with the second preset temperature value Tset2 to obtain the outdoor cooling demand CFr2. The first outlet pressure P4 and/or the first outlet temperature T3 at the outlet of the condensing unit 23 are collected. The determination of the outdoor outlet superheat degree SHr2 of the second heat exchange conduit 212 is performed by collecting the fourth outlet temperature T6 and/or the fourth outlet pressure P7 of the outlet of the first heat exchange conduit 211, and calculating according to the superheat degree calculation formula to determine the second change The outdoor outlet superheat degree SHr2 of the heat pipe 212. Specifically, the fourth outlet temperature T6 at two points of the second heat exchange conduit 212 exit, or the fourth outlet pressure Ρ6 at two points, or the fourth outlet temperature Τ6 and the fourth outlet pressure Ρ7 at any point are collected, The outdoor outlet superheat SHr2 can be calculated.

[0086] S22: The second control unit 25 controls the start-stop or capacity output of the compressor 22 according to the outdoor cooling demand CFr2. As shown in FIG. 9, step S22 includes the following steps: comparing the outdoor cooling demand CFr2 with a preset second cooling threshold C Fset2, and if the outdoor cooling demand CFr2 is greater than the second cooling threshold CFset2, controlling the starting of the compressor 2 2 and adjusting The capacity output of the compressor 22, if not, controls the compressor 22 to stop operating.

[0087] and / or

[0088] S23: The second control unit 25 controls the capacity output of the condensing device 23 according to the first outlet pressure P4 and/or the first outlet temperature T3 of the outlet of the condensing device 23. As shown in FIG. 10, step S23 includes the following steps: The second control unit 25 converts the first outlet temperature T3 into a corresponding outlet pressure value by calculation, and the corresponding outlet pressure value or the first outlet pressure P4 is preset. The pressure threshold range Psetl is compared. If the corresponding outlet pressure value or first outlet pressure P4 is greater than the pressure threshold range, the capacity output of the condensing device 23 is increased. If the corresponding outlet pressure value or first outlet pressure P4 is less than the pressure threshold range Pset1, the capacity output of the condensing device 23 is reduced. If the corresponding outlet pressure value or the first outlet pressure P4 is within the pressure threshold range Psetl Then, the capacity output of the condensing device 23 is maintained.

[0089] It can be understood that if the condensing device 23 adopts an air-cooling unit, that is, the condensing device 23 includes an outdoor fan 232 that is coupled between the compressor 22 and the second flow control valve 24 and the outdoor condenser 231. Then, the second control unit 25 can control the capacity output of the outdoor fan 232 according to the first outlet pressure P4 and/or the first outlet temperature T3 of the outlet of the outdoor condenser 231, that is, control the rotational speed of the outdoor fan 232.

[0090] If the condensing device 23 employs a water-cooling unit, the condensing unit 23 includes an outdoor condenser 231 connected between the compressor 22 and the second flow control valve 24, and a cooling water output device 233 coupled to the outdoor condenser 231, The second control unit 25 can control the capacity output of the control cooling water output device 233 according to the first outlet pressure P4 and/or the first outlet temperature T3 of the outlet of the outdoor condenser 231.

[0091] and / or

[0092] S24: controlling the temperature Xr2 of the second flow control valve 24 according to the outdoor outlet superheat degree SHr2 of the second heat exchange conduit 212. As shown in FIG. 11, step S24 includes the following steps: The second control unit 25 compares the outdoor outlet superheat degree S Hr2 with a preset second superheat degree threshold range SHset2, if the outdoor outlet superheat degree SHr2 is smaller than the second superheat degree threshold range SHset2, then reduces the twist Xr2 of the second flow control valve 24. If the outdoor outlet superheat SHr2 is greater than the second superheat threshold range SHset2, the twist Xr2 of the second flow control valve 24 is increased. If the outdoor outlet superheat degree SHr2 is within the second superheat degree threshold range SHset2, the twist Xr2 of the second flow control valve 24 is maintained.

[0093] It can be understood that the second control unit 25 does not affect the control of the second flow control valve 24, the condensing device 23, and the compressor 22, that is, there is no order between the two, and is independently controlled according to respective control conditions. Specifically, the second control unit 25 controls the second flow rate control valve 24, the condensing unit 23, and the compressor 22 by a PID control method or a P control method.

According to the control method of the multiple refrigeration system provided by the present invention, the first control unit 13 obtains the indoor cooling demand CFrl, the indoor outlet superheat degree SHrl, and the differential pressure ΔΡ before and after the delivery pump 32, and independently controls the first Flow control valve 11 and delivery pump 32;

The second control unit 25 actually obtains the outdoor cooling demand CFr2, the first outlet pressure P4 of the outlet of the condensing device 23, and/or the first outlet temperature T3 and the outdoor outlet superheat degree SHr2, and independently controls the compressor 22, the condensing device 23, and the The mobility of the two flow control valve 24, the control method of the multiple refrigeration system is simple and easy to implement, and the corresponding components of the multiple refrigeration system are independently controlled to avoid the energy control caused by the associated control of multiple components. Fee.

The present invention has been described in terms of several specific embodiments, and those skilled in the art will understand that various modifications and equivalents can be made to the present invention without departing from the scope of the invention. In addition, various modifications may be made to the invention without departing from the scope of the invention. Therefore, the invention is not limited to the specific embodiments disclosed, but all the embodiments falling within the scope of the appended claims.

Claims

Claim

[Claim 1] A multiple refrigeration system, comprising at least one indoor refrigeration unit (10)

At least one outdoor refrigeration unit (20), and for connecting the indoor refrigeration unit (

10) and a cold conveying unit (30) of the outdoor refrigeration unit (20);

The cold delivery unit (30) includes a liquid storage device (31) for storing phase change refrigerant and a transfer pump (32) connected to the liquid storage device (31);

The outdoor refrigeration unit (20) includes a partition wall heat exchange unit (21), and the partition wall heat exchange unit (21) includes mutually independent first heat exchange tubes (21 1) and second for performing heat exchange. a heat exchange pipe (212); the indoor refrigeration unit (10), the cold conveying unit (30) and the first heat exchange pipe (211) form a closed cycle;

The indoor refrigeration unit (10) includes a first flow control valve (11) connected to an outlet of the transfer pump (32), an outlet of the first flow control valve (11), and the first heat exchange conduit ( 211) an indoor evaporator (12) connected to the inlet, and a first control unit (13), the first control unit (13) and the first flow control valve (11) and the transfer pump (32) Connected, for controlling the first flow control valve according to indoor refrigeration demand (

11) and starting and stopping of the transfer pump (32), controlling the temperature of the first flow control valve (11) according to the indoor outlet superheat of the indoor evaporator (12), according to the transfer pump

(32) The differential pressure before and after the control controls the capacity output of the transfer pump (32);

The outdoor refrigeration unit (20) further includes a compressor (22) connected to an outlet of the second heat exchange conduit (212), a condensing device (23) connected to an outlet of the compressor (22), and a second flow control valve (24) connected to the inlet of the second heat exchange conduit (212) and a second control portion (25), wherein the second control portion (25) is respectively a compressor (22), the second flow control valve (24) and the condensing device (23) are connected to control start/stop or capacity output of the compressor (22) according to an outdoor cooling demand, according to the The first outlet pressure of the outlet of the condensing unit (23) and/or the first outlet temperature controls the capacity output of the condensing unit (23) and is controlled according to the outdoor outlet superheat of the second heat exchange conduit (212) The twist of the second flow control valve (24).

[Claim 2] The multiple refrigeration system according to claim 1, wherein the at least one indoor refrigeration unit (10) includes at least two indoor refrigeration units (10) arranged in parallel.

[Claim 3] The multiple refrigeration system according to claim 2, further comprising an indoor fan (14) cooperating with the indoor evaporator (12), the first control portion (13) and the The indoor fan (14) is connected to control the intensity or capacity output of the indoor fan (14) according to the indoor cooling demand.

[Claim 4] The multiple refrigeration system according to any one of claims 1-3, wherein the outdoor refrigeration unit (20) comprises at least two outdoor refrigeration units (20) arranged in series, The first heat exchange tubes (211) of the at least two outdoor refrigeration units (20) are connected; the outdoor refrigeration unit (20) includes at least two outdoor refrigeration units (20) arranged in parallel, the at least two outdoor refrigeration units (20) sharing a partition wall heat exchange unit (21) and a second flow control valve (24), and coupling at least two compressors (22) of the at least two outdoor refrigeration units (20) Into the second heat exchange conduit (212) outlet of the partition wall heat exchange unit (21), at least two condensing devices (23) are connected in parallel to the at least two compressor (22) outlets and the second flow a control valve (24) inlet; the outdoor refrigeration unit (20) includes at least two outdoor refrigeration units (20) arranged in parallel, and a first heat exchange conduit (211) outlet of the at least two outdoor refrigeration units (20) Separate reservoir Means (31) is connected.

[Claim 5] The multiple refrigeration system according to claim 4, wherein the condensing device (2)

3) comprising an outdoor fan (23 2) coupled to the outdoor condenser (231) connected between the compressor (22) and the second flow control valve (24) and the outdoor condenser (231), The second control unit (25) is connected to the outdoor fan (232) for controlling the outdoor fan according to a first outlet pressure and/or a first outlet temperature of the outdoor condenser (231) outlet. Capacity output;

Or

The condensing device (23) includes a compressor connected to the compressor (22) and the second flow control An outdoor condenser (231) between the valve (24) and a cooling water output device (233) cooperating with the outdoor condenser (231), the second control unit (25) controlling the cooling water output device (233) Capacity output.

[Claim 6] A control method of a multiple refrigeration system, comprising: the first control unit (13) performing the following steps:

S11: obtaining indoor refrigeration demand, indoor outlet superheat of the indoor evaporator (12), and pressure difference before and after the pump (32);

S12: Control the first flow control valve (11) and the transfer pump according to indoor refrigeration demand (32)

Start and stop;

S13: controlling the twist of the first flow control valve (11) according to the indoor outlet superheat of the indoor evaporator (12);

S14: controlling the capacity output of the transfer pump (32) according to a pressure difference before and after the transfer pump (32);

It also includes the following steps performed by the second control unit (25):

S21: determining an outdoor cooling demand, a first outlet pressure of the outlet of the condensing device (23) and/or a first outlet temperature, and an outdoor outlet superheat of the second heat exchange conduit (212);

S22: controlling start/stop or capacity output of the compressor (22) according to outdoor cooling demand; S23: controlling the condensing device according to a first outlet pressure and/or a first outlet temperature of the outlet of the condensing device (23) ( 23) capacity output;

S24: controlling the second according to the outdoor outlet superheat of the second heat exchange conduit (212)

[Claim 7] The control method of the multiple refrigeration system according to claim 6, wherein the step S11 comprises: collecting an indoor ambient temperature, and performing the indoor ambient temperature and the first preset temperature value Comparing, calculating a temperature difference between the two to determine the indoor refrigeration demand; collecting a second outlet temperature and/or a second outlet pressure of the outlet of the indoor evaporator (12), calculating to determine the indoor outlet superheat; collecting the The pump inlet pressure and the pump outlet pressure of the transfer pump (32) are calculated to obtain the pressure difference before and after the transfer pump (32).

[Claim 8] The control method of the multiple refrigeration system according to claim 7, wherein The step S12 includes: comparing the indoor cooling demand with a preset first cooling threshold, and if the indoor cooling demand is greater than or equal to the first cooling threshold, controlling the first flow control valve (11) And the transfer pump (32) is started, if not, controlling the first flow control valve (11) and the transfer pump (32) to stop working;

and / or

The step S13 includes: comparing the indoor outlet superheat degree with a preset first superheat degree threshold range, and if the indoor outlet superheat degree is less than the first superheat degree threshold range, decreasing the first flow rate Controlling the degree of twist of the valve (11); if the indoor outlet superheat is greater than the first superheat threshold range, increasing the twist of the first flow control valve (11); Maintaining the twist of the first flow control valve (11) within the first superheat threshold range;

and / or

The step S14 includes: comparing the pressure difference value with a preset pressure difference threshold value range, and if the pressure difference value is smaller than the pressure difference threshold value range, reducing a capacity output of the delivery pump (32); And the pressure difference value is greater than the pressure difference threshold range, thereby increasing a capacity output of the transfer pump (32); if the pressure difference value is within the pressure difference threshold range, maintaining the transfer pump ( 32) Capacity output.

[Claim 9] The control method of the multiple refrigeration system according to any one of claims 6-8, characterized in that

The step S21 includes: collecting a third outlet temperature, a third outlet pressure, a first inlet pressure or a first inlet temperature of the outlet of the first heat exchange conduit (211), and the third outlet temperature and the third outlet pressure Calculating a first inlet pressure or a first inlet temperature and a second preset temperature value to obtain the outdoor refrigeration demand; collecting a fourth outlet temperature and/or a fourth outlet pressure of the second heat exchange conduit (212) outlet Calculated to determine the outdoor outlet superheat

[Claim 10] The control method of the multiple refrigeration system according to claim 9, wherein

The step S22 includes: comparing the outdoor cooling demand with a preset second cooling threshold, and if the outdoor cooling demand is greater than the second cooling threshold, controlling the starting a compressor (22) and adjusting a capacity output of the compressor (22), and if not, controlling the compressor (22) to stop working;

and / or

The step S23 includes: converting the first outlet temperature into a corresponding outlet pressure value by calculation, and comparing the corresponding outlet pressure value or the first outlet pressure with a preset pressure threshold range; If the corresponding outlet pressure value or the first outlet pressure is greater than the pressure threshold range, increasing the capacity output of the condensing device (23); if the corresponding outlet pressure value or the first outlet pressure Less than the pressure threshold range, reducing the capacity output of the condensing device (23); maintaining the condensation if the corresponding outlet pressure value or the first outlet pressure is within the pressure threshold range Capacity output of the device (23);

and / or

The step S24 includes: comparing the outdoor outlet superheat degree with a preset second superheat degree threshold range, and if the outdoor outlet superheat degree is less than the second superheat degree threshold range, decreasing the second flow rate Controlling the degree of twist of the valve (24); if the outdoor outlet superheat is greater than the second superheat threshold range, increasing the twist of the second flow control valve (24); Within the second superheat threshold range,