CN113803901A - Direct expansion type air conditioning unit and control method and device thereof - Google Patents
Direct expansion type air conditioning unit and control method and device thereof Download PDFInfo
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- CN113803901A CN113803901A CN202111036609.0A CN202111036609A CN113803901A CN 113803901 A CN113803901 A CN 113803901A CN 202111036609 A CN202111036609 A CN 202111036609A CN 113803901 A CN113803901 A CN 113803901A
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- 238000004378 air conditioning Methods 0.000 title claims abstract description 53
- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000003507 refrigerant Substances 0.000 claims abstract description 38
- 238000001704 evaporation Methods 0.000 claims abstract description 15
- 230000008020 evaporation Effects 0.000 claims abstract description 13
- 239000007788 liquid Substances 0.000 claims description 14
- 125000000086 dCMP group Chemical group 0.000 claims description 3
- 238000005057 refrigeration Methods 0.000 abstract description 9
- 230000000694 effects Effects 0.000 abstract description 6
- 238000012546 transfer Methods 0.000 abstract description 2
- 230000007306 turnover Effects 0.000 abstract 1
- 230000001276 controlling effect Effects 0.000 description 49
- 238000007791 dehumidification Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 230000006870 function Effects 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 230000008014 freezing Effects 0.000 description 2
- 238000007710 freezing Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
- F25B5/02—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in parallel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
- F25B41/31—Expansion valves
- F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B6/00—Compression machines, plants or systems, with several condenser circuits
- F25B6/02—Compression machines, plants or systems, with several condenser circuits arranged in parallel
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
Abstract
The application relates to a direct expansion type air conditioning unit and a control method and a device thereof, wherein the direct expansion type air conditioning unit comprises a water-cooled condenser and an air-cooled condenser, the water-cooled condenser and the air-cooled condenser are connected in parallel, a first-stage evaporator and a second-stage evaporator which are respectively connected with the water-cooled condenser and the air-cooled condenser, a main electronic expansion valve used for adjusting the flow of a refrigerant passing through the water-cooled condenser, an auxiliary electronic expansion valve used for adjusting the flow of the refrigerant passing through the air-cooled condenser and a DDC controller, and the DDC controller is respectively connected with the main electronic expansion valve and the auxiliary electronic expansion valve. This application is through setting up doublestage evaporimeter increase heat transfer area, and increase evaporating temperature avoids frosting to, adjust through the doublestage evaporation, can realize the low humidity air supply of low temperature, when the business turn over wind difference in temperature is great, still can keep good refrigeration effect.
Description
Technical Field
The application belongs to the technical field of air conditioning units, and particularly relates to a direct expansion type air conditioning unit and a control method and device thereof.
Background
The direct expansion air conditioning unit is provided with a compressor, liquid refrigerant in a refrigerating system directly exchanges heat with air to be treated outside a coil in an evaporator coil, and absorbs heat of the air outside the coil to be directly evaporated, so that the air outside the coil is refrigerated. Because the refrigerant directly completes heat exchange with the air to be treated, the air outside the coil pipe is not absorbed by secondary heat exchange in the middle to realize refrigeration, the heat exchange efficiency is high, the temperature regulation range is wide, and the air-conditioning system is widely applied to various industries. The traditional direct expansion type air conditioning unit has poor temperature and humidity adjusting capacity and narrow applicable range, and the refrigeration effect is not obvious on occasions with obvious heat and humidity load change, such as large temperature difference of inlet and outlet air. In addition, the dehumidification capacity is weak during freezing dehumidification, and the safety problems of frost formation, ice blockage and the like exist when the air conditioner is applied to the air supply field with low air supply dew point temperature.
Disclosure of Invention
In order to overcome the problems that the traditional direct-expansion air conditioning unit has an unobvious refrigeration effect on some occasions with obvious heat and humidity load changes and has safety such as frosting, ice blockage and the like when being applied to the air supply field with low air supply dew point temperature at least to a certain extent, the application provides the direct-expansion air conditioning unit and a control method and a control device thereof.
In a first aspect, the present application provides a direct expansion air conditioning unit comprising:
the water-cooled condenser and the air-cooled condenser are connected in parallel;
the primary evaporator and the secondary evaporator are respectively connected with the water-cooled condenser and the air-cooled condenser;
the main electronic expansion valve is used for adjusting the flow of the refrigerant passing through the water-cooled condenser, and the auxiliary electronic expansion valve and the DDC controller are used for adjusting the flow of the refrigerant passing through the air-cooled condenser;
the DDC controller is respectively connected with the main electronic expansion valve and the auxiliary electronic expansion valve.
Further, the method also comprises the following steps:
a primary compressor and a secondary compressor;
the inlet of the primary compressor is connected with the outlet of the primary evaporator;
the inlet of the secondary compressor is connected with the outlet of the secondary evaporator;
the outlet of the primary compressor is respectively connected with the inlet of the water-cooled condenser and the inlet of the air-cooled condenser;
and the outlet of the secondary compressor is respectively connected with the inlet of the water-cooled condenser and the inlet of the air-cooled condenser.
Further, the method also comprises the following steps:
and the electromagnetic valve is arranged between the inlet of the air-cooled condenser and the exhaust outlets of the primary compressor and the secondary compressor.
Further, the method also comprises the following steps:
the main electronic expansion valve is arranged between the outlet of the water-cooled condenser and the inlets of the first-stage evaporator and the second-stage evaporator;
the auxiliary electronic expansion valve is arranged between the outlet of the air-cooled condenser and the inlets of the first-stage evaporator and the second-stage evaporator.
Further, the method also comprises the following steps:
a primary gas-liquid separator and a secondary gas-liquid separator;
the first-stage gas-liquid separator is arranged between an inlet of the first-stage compressor and an outlet of the first-stage evaporator;
the second-stage gas-liquid separator is arranged between an inlet of the second-stage compressor and an outlet of the second-stage evaporator.
Further, the method also comprises the following steps:
the evaporation area of the first-stage evaporator is larger than that of the second-stage evaporator.
In a second aspect, the present application provides a direct expansion type air conditioning unit control method, including:
acquiring air conditioner operation parameters;
controlling the opening degree of a main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters;
and/or the presence of a gas in the gas,
and controlling the opening of an auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air-conditioner operation parameters.
Further, the air conditioner operation parameters include:
at least one of the outlet air temperature, outlet air humidity, return air temperature and suction superheat degree.
Further, the method also comprises the following steps:
calculating the outlet air moisture content according to the outlet air temperature and the outlet air humidity;
and when the outlet air moisture content is greater than the target outlet air moisture content set value, controlling the primary compressor to be started.
Further, the wind outlet moisture content is calculated according to the wind outlet temperature and the wind outlet humidity, and the method comprises the following steps:
inputting the outlet air temperature into an empirical formula to calculate the outlet air moisture content, wherein the empirical formula is as follows:
d1＝622*{RH4*133exp[18.5916-3991.11/(T4+233.84)]}/{101300-RH4*133exp[18.5916-3991.11/(T4+233.84)]}
wherein d1 is the outlet air moisture content, T4 is the outlet air temperature, and RH4 is the outlet air humidity.
Further, the method also comprises the following steps:
and controlling the state of an electromagnetic valve according to the comparison result of the return air temperature and the return air temperature set value, wherein the electromagnetic valve is arranged between the inlet of the air-cooled condenser and the exhaust outlets of the primary compressor and the secondary compressor and is used for controlling the on-off of the inlet passage of the air-cooled condenser.
Further, the control according to return air temperature and return air temperature set value comparison result is used for controlling the solenoid valve state, includes:
if the return air temperature is less than the set return air temperature value, controlling the electromagnetic valve to open;
and if the return air temperature is not less than the set return air temperature value and the opening degree of the auxiliary electronic expansion valve is opened to the minimum step number, controlling the electromagnetic valve to be closed.
Further, the controlling the opening of the auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air-conditioning operation parameter includes:
if the return air temperature is more than or equal to T-1, controlling the opening of the auxiliary electronic expansion valve to be reduced;
if the T-delta T-1 is greater than the return air temperature and less than T-1, controlling the opening of the auxiliary electronic expansion valve to be unchanged;
if the return air temperature is less than or equal to T-delta T-1, controlling the opening of the auxiliary electronic expansion valve to be increased;
wherein T is the return air temperature target value, and Delta T is the difference value of the return air temperature and the return air temperature target value.
Further, the method also comprises the following steps:
and when the frequency of the first-stage compressor reaches the maximum frequency set value, controlling the second-stage compressor to be started.
Further, the controlling the opening degree of a main electronic expansion valve used for adjusting the flow rate of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters comprises:
after the secondary compressor is started, the opening degree of the main electronic expansion valve is adjusted according to the deviation between the suction superheat degree and the target suction superheat degree set value.
Further, the adjusting the opening degree of the main electronic expansion valve includes:
if the deviation of the suction superheat degree is larger than the target suction superheat degree set value, controlling the opening of the main electronic expansion valve to be increased;
if the suction superheat deviation is more than 0 and less than or equal to the target suction superheat set value, controlling the opening of the main electronic expansion valve to be unchanged;
and if the deviation of the suction superheat degree is less than or equal to 0, controlling the opening degree of the auxiliary electronic expansion valve to be reduced.
Further, the method also comprises the following steps:
and adjusting the frequency of a compressor according to the air outlet moisture content, wherein the compressor comprises a primary compressor and/or a secondary compressor.
Further, the frequency of the compressor is adjusted according to the outlet air moisture content, and the method comprises the following steps:
if d1 is greater than dcm, controlling the frequency of the compressor to increase according to a first time interval;
if the dcm is more than or equal to d1 and is more than the dcm-dcm, controlling the frequency of the compressor to keep unchanged;
if the dcm-dcmp-1 is more than or equal to d1 and more than the dcm-dcmp-2, controlling the frequency of the compressor to be reduced according to a second time interval until the detected frequency is the lowest frequency;
and d1 is the outlet air moisture content, dcm is the target outlet air moisture content set value, and dcmp is the difference between the outlet air moisture content and the target outlet air moisture content set value.
In a third aspect, the present application provides a direct expansion air conditioning unit control apparatus comprising:
the acquisition module is used for acquiring the operating parameters of the air conditioner;
the control module is used for controlling the opening of a main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters;
and/or the presence of a gas in the gas,
and controlling the opening of an auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air-conditioner operation parameters.
The technical scheme provided by the embodiment of the application can have the following beneficial effects:
the direct expansion type air conditioner unit and the control method and device thereof provided by the embodiment of the invention are characterized in that the direct expansion type air conditioner unit comprises a water-cooled condenser and an air-cooled condenser, wherein the water-cooled condenser is connected with the air-cooled condenser in parallel, a first-stage evaporator and a second-stage evaporator which are respectively connected with the water-cooled condenser and the air-cooled condenser, a main electronic expansion valve used for adjusting the flow of a refrigerant passing through the water-cooled condenser, an auxiliary electronic expansion valve used for adjusting the flow of the refrigerant passing through the air-cooled condenser and a DDC controller which is respectively connected with the main electronic expansion valve and the auxiliary electronic expansion valve, the heat exchange area is increased by arranging the two-stage evaporator, the evaporation temperature is increased, the frosting is avoided, in addition, the low-temperature and low-humidity air supply can be realized through the two-stage evaporation adjustment, and the good refrigeration effect can be still kept when the temperature difference between the inlet air and the outlet air is large.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
Fig. 1 is a schematic structural diagram of a direct expansion air conditioning unit according to an embodiment of the present application.
Fig. 2 is a flowchart of a method for controlling a direct expansion air conditioning unit according to an embodiment of the present application.
Fig. 3 is a flowchart of a method for controlling a direct expansion air conditioning unit according to another embodiment of the present application.
Fig. 4 is a functional structure diagram of a direct expansion air conditioning unit control device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present application.
Fig. 1 is a schematic structural diagram of a direct expansion type air conditioning unit according to an embodiment of the present application, and as shown in fig. 1, the direct expansion type air conditioning unit includes:
the water-cooled condenser 101 and the air-cooled condenser 102 are connected in parallel;
a primary evaporator 103 and a secondary evaporator 104 connected to the water-cooled condenser 101 and the air-cooled condenser 102, respectively;
a main electronic expansion valve 105 for adjusting the flow rate of the refrigerant passing through the water-cooled condenser 101, an auxiliary electronic expansion valve 106 for adjusting the flow rate of the refrigerant passing through the air-cooled condenser 102, and a DDC controller 107;
the DDC controller 107 is connected to the main electronic expansion valve 105 and the auxiliary electronic expansion valve 106, respectively.
The DDC (Direct Digital Control) controller comprises a central Control device, a color monitor, a keyboard, a printer, an uninterruptible power supply, a communication interface and the like.
The traditional direct expansion type air conditioning unit has poor temperature and humidity adjusting capacity and narrow applicable range, and the refrigeration effect is not obvious on occasions with obvious heat and humidity load change, such as large temperature difference of inlet and outlet air. In addition, the dehumidification capacity is weak during freezing dehumidification, and the safety problems of frost formation, ice blockage and the like exist when the air conditioner is applied to the air supply field with low air supply dew point temperature.
In this embodiment, the direct-expansion air conditioning unit includes a water-cooled condenser and an air-cooled condenser, the water-cooled condenser is connected in parallel with the air-cooled condenser, a first-stage evaporator and a second-stage evaporator respectively connected with the water-cooled condenser and the air-cooled condenser, a main electronic expansion valve for adjusting the flow of refrigerant passing through the water-cooled condenser, an auxiliary electronic expansion valve for adjusting the flow of refrigerant passing through the air-cooled condenser, and a DDC controller respectively connected with the main electronic expansion valve and the auxiliary electronic expansion valve.
As shown in fig. 1, the direct expansion type air conditioning unit further includes:
a primary compressor 108 and a secondary compressor 109;
the inlet of the first-stage compressor 108 is connected with the outlet of the first-stage evaporator 103;
the inlet of the secondary compressor 109 is connected to the outlet of the secondary evaporator 104;
the outlet of the first-stage compressor 108 is respectively connected with the inlet of the water-cooled condenser 101 and the inlet of the air-cooled condenser 102;
the outlet of the secondary compressor 109 is connected to the inlet of the water-cooled condenser 101 and the inlet of the air-cooled condenser 102, respectively.
And the electromagnetic valve 110 is arranged between the inlet of the air-cooled condenser 102 and the exhaust outlets of the primary compressor 108 and the secondary compressor 109.
The main electronic expansion valve 105 is arranged between the outlet of the water-cooled condenser 101 and the inlets of the first-stage evaporator 103 and the second-stage evaporator 104;
the auxiliary electronic expansion valve 106 is arranged between the outlet of the air-cooled condenser 101 and the inlets of the first-stage evaporator 103 and the second-stage evaporator 104.
A primary gas-liquid separator 111 and a secondary gas-liquid separator 112;
the first-stage gas-liquid separator 111 is arranged between the inlet of the first-stage compressor 108 and the outlet of the first-stage evaporator 103;
the secondary gas-liquid separator 112 is provided between an inlet of the secondary compressor 109 and an outlet of the secondary evaporator 104.
In some embodiments, further comprising:
the evaporation area of the primary evaporator 103 is larger than that of the secondary evaporator 104.
Not only the evaporation area is enlarged, but also the evaporation area of the first-stage evaporator 103 is larger than that of the second-stage evaporator 104, so that the requirements of large temperature difference of inlet and outlet air and low air outlet temperature are met.
Meanwhile, the frequency of the two-stage compressor is adjusted, so that the secondary evaporator is guaranteed to have enough evaporation temperature, and the problem that the evaporator frosts due to the fact that the evaporation temperature is too low is solved.
When the refrigeration cycle is in operation, low-temperature and low-pressure refrigerant steam is sucked and compressed from the evaporator by the stage compressor, the compressed high-temperature and high-pressure gas is discharged by the compressor through the tee joint (Y-shaped pipe), one path of the high-temperature and high-pressure gas enters the air-cooled condenser, the other path of the high-temperature and low-pressure gas enters the water-cooled condenser, the high-temperature and high-pressure gas is throttled and decompressed by the electronic expansion valve after being condensed by the air-cooled condenser and the water-cooled condenser and enters the stage evaporator, and finally the low-temperature and low-pressure gas returns to the compressor to finish the refrigeration cycle.
In this embodiment, adopt doublestage evaporation to effectively improve the heat transfer area of heat exchanger, improve evaporating temperature and do not reduce to very low, realize that the operating mode is undulant greatly in the air inlet operating mode, the variable blast volume, the abominable operating mode such as dehumidification is big, according to different cold load operating modes, realizes energy-conserving operation modes such as doublestage full-open or single-open one-level simultaneously, promotes energy-conservation nature.
Fig. 2 is a flowchart of a direct expansion air conditioning unit control method according to an embodiment of the present application, and as shown in fig. 2, the direct expansion air conditioning unit control method includes:
s21: obtaining air conditioner operating parameters including, but not limited to: the air outlet temperature, the air outlet humidity, the air return temperature and the air suction superheat degree.
S22: calculating the air outlet moisture content according to the air outlet temperature and the air outlet humidity;
s23: and when the outlet air moisture content is greater than the target outlet air moisture content set value, controlling the primary compressor to be started.
In some embodiments, calculating the outlet air moisture content according to the outlet air temperature and the outlet air humidity includes:
the air outlet temperature is input into an empirical formula to calculate the air outlet moisture content, and the empirical formula is as follows:
d1＝622*{RH4*133exp[18.5916-3991.11/(T4+233.84)]}/{101300-RH4*133exp[18.5916-3991.11/(T4+233.84)]}
wherein d1 is the outlet air moisture content, T4 is the outlet air temperature, and RH4 is the outlet air humidity.
It should be noted that the outlet air moisture content is similar to the return air moisture content calculation method, and in some embodiments, the primary compressor may be controlled to be turned on according to the return air moisture content.
The empirical formula of the moisture content of return air is as follows:
dn＝622*{RH2*133exp[18.5916-3991.11/(T2+233.84)]}/{101300-RH2*133exp[18.5916-3991.11/(T2+233.84)]}
where dn is the return air moisture content, T2 is the return air temperature, and RH2 is the return air humidity.
S24: and the electromagnetic valve is arranged between the inlet of the air-cooled condenser and the exhaust outlets of the primary compressor and the secondary compressor and is used for controlling the on-off of the inlet passage of the air-cooled condenser.
In some embodiments, controlling the state of the solenoid valve based on the comparison of the return air temperature to the return air temperature setpoint comprises:
if the return air temperature is less than the set return air temperature value, controlling the electromagnetic valve to open;
and if the return air temperature is not less than the set return air temperature value and the opening degree of the auxiliary electronic expansion valve is opened to the minimum step number, controlling the electromagnetic valve to be closed.
S25: and controlling the opening of an auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the operation parameters of the air conditioner.
In some embodiments, controlling an opening of an auxiliary electronic expansion valve for regulating a flow of refrigerant through the air-cooled condenser based on an air conditioner operating parameter includes:
if the return air temperature is more than or equal to T-1, controlling the opening of the auxiliary electronic expansion valve to be reduced;
if the T-delta T-1 is greater than the return air temperature and less than T-1, controlling the opening of the auxiliary electronic expansion valve to be unchanged;
if the return air temperature is less than or equal to T-delta T-1, controlling the opening of the auxiliary electronic expansion valve to be increased;
wherein T is the return air temperature target value, and Delta T is the difference value of the return air temperature and the return air temperature target value.
S25 is executed by the PID operation of the DDC controller to adjust the opening degree of the auxiliary electronic expansion valve, thereby adjusting the refrigerant flow rate passing through the air-cooled condenser and adjusting the temperature of the reheated air.
In this embodiment, the outlet air moisture content is calculated by collecting the outlet air temperature and humidity parameters, and compared with a set outlet air moisture content target value, the opening and closing of the electromagnetic valve on one side of the air-cooled condenser are controlled, and then the DDC controller automatically adjusts the opening of the auxiliary electronic expansion valve through PID adjustment, controls the flow of the refrigerant entering the air-cooled condenser, and further controls the reheat, thereby achieving the purpose of adjusting the outlet air temperature.
An embodiment of the present invention provides another direct expansion type air conditioning unit control method, as shown in a flowchart in fig. 3, and as shown in fig. 3, the direct expansion type air conditioning unit control method includes:
s31: obtaining air conditioner operating parameters including, but not limited to: the air outlet temperature, the air outlet humidity, the return air temperature and the suction superheat degree;
s32: calculating the air outlet moisture content according to the air outlet temperature and the air outlet humidity;
s33: and when the outlet air moisture content is greater than the target outlet air moisture content set value, controlling the primary compressor to be started.
S34: and when the frequency of the first-stage compressor reaches the maximum frequency set value, controlling the second-stage compressor to be started.
S35: and adjusting the frequency of the compressor according to the moisture content of the outlet air, wherein the compressor comprises a primary compressor and/or a secondary compressor.
In some embodiments, modulating the frequency of the compressor based on the outlet air moisture content comprises:
if d1 is greater than dcm, controlling the frequency of the compressor to increase according to a first time interval;
if the dcm is more than or equal to d1 and is more than the dcm-dcm, controlling the frequency of the compressor to keep unchanged;
if the dcm-dcmp-1 is more than or equal to d1 and more than the dcm-dcmp-2, controlling the frequency of the compressor to be reduced according to a second time interval until the detected frequency is the lowest frequency;
and d1 is the outlet air moisture content, dcm is the target outlet air moisture content set value, and dcmp is the difference between the outlet air moisture content and the target outlet air moisture content set value.
The temperature and the humidity can be continuously adjusted by adjusting the frequency of the compressor, and the functions of adjusting the constant temperature and the constant humidity with high precision are realized.
S36: after the secondary compressor is started, the opening degree of the main electronic expansion valve is adjusted according to the deviation between the suction superheat degree and the target suction superheat degree set value.
In some embodiments, adjusting the opening degree of the main electronic expansion valve comprises:
if the deviation of the suction superheat degree is larger than the target suction superheat degree set value, controlling the opening of the main electronic expansion valve to be increased;
if the suction superheat deviation is more than 0 and less than or equal to the target suction superheat set value, controlling the opening of the main electronic expansion valve to be unchanged;
and if the deviation of the suction superheat degree is less than or equal to 0, controlling the opening degree of the auxiliary electronic expansion valve to be reduced.
In the embodiment, the opening degree of the main electronic expansion valve is adjusted, the flow of the refrigerant of the evaporator is adjusted, a certain suction superheat degree is ensured, and suction liquid waiting is avoided.
An embodiment of the present invention provides a direct expansion type air conditioning unit control device, as shown in a functional structure diagram of fig. 4, the direct expansion type air conditioning unit control device including:
an obtaining module 41, configured to obtain an air conditioner operation parameter;
the control module 42 is used for controlling the opening of a main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters;
and/or the presence of a gas in the gas,
and controlling the opening of an auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air-conditioner operation parameters.
In some embodiments, further comprising:
the calculation module 43 is configured to calculate an outlet air moisture content according to the outlet air temperature and the outlet air humidity;
and the adjusting module 44 is used for adjusting the frequency of the compressor according to the outlet air moisture content, wherein the compressor comprises a primary compressor and/or a secondary compressor.
In some embodiments, the control module 42 includes:
the first control unit is used for controlling the opening degree of a main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the operation parameters of the air conditioner;
a second control unit for controlling the opening of the auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the operation parameters of the air conditioner
And the third control unit is used for controlling the primary compressor to be started when the outlet air moisture content is greater than the target outlet air moisture content set value.
And the fourth control unit is used for controlling the state of the electromagnetic valve according to the comparison result of the return air temperature and the return air temperature set value, and the electromagnetic valve is arranged between the inlet of the air-cooled condenser and the exhaust outlets of the primary compressor and the secondary compressor and is used for controlling the on-off of the inlet passage of the air-cooled condenser.
In the embodiment, the air conditioner operation parameters are acquired through the acquisition module, the control module controls the opening of the main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters, and/or controls the opening of the auxiliary electronic expansion valve used for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air conditioner operation parameters, the heat exchange area of the heat exchanger is effectively increased by adopting two-stage evaporation, the evaporation temperature is not reduced to be very low, the severe working conditions such as large fluctuation of air inlet working conditions, variable air volume and large dehumidification are realized, meanwhile, according to different cold load working conditions, energy-saving operation modes such as two-stage full-open or single-open one-stage are realized, the energy conservation is improved, low-temperature and low-humidity air supply can be realized, and when the temperature difference between inlet air and outlet air is large, a good refrigeration effect can be still kept.
It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.
It should be noted that, in the description of the present application, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present application, the meaning of "a plurality" means at least two unless otherwise specified.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and the scope of the preferred embodiments of the present application includes other implementations in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present application.
It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
It should be noted that the present invention is not limited to the above-mentioned preferred embodiments, and those skilled in the art can obtain other products in various forms without departing from the spirit of the present invention, but any changes in shape or structure can be made within the scope of the present invention with the same or similar technical solutions as those of the present invention.
Claims (19)
1. A direct expansion type air conditioning unit, characterized by comprising:
the water-cooled condenser and the air-cooled condenser are connected in parallel;
the primary evaporator and the secondary evaporator are respectively connected with the water-cooled condenser and the air-cooled condenser;
the main electronic expansion valve is used for adjusting the flow of the refrigerant passing through the water-cooled condenser, and the auxiliary electronic expansion valve and the DDC controller are used for adjusting the flow of the refrigerant passing through the air-cooled condenser;
the DDC controller is respectively connected with the main electronic expansion valve and the auxiliary electronic expansion valve.
2. A direct-expansion air conditioning unit according to claim 1, characterized by further comprising:
a primary compressor and a secondary compressor;
the inlet of the primary compressor is connected with the outlet of the primary evaporator;
the inlet of the secondary compressor is connected with the outlet of the secondary evaporator;
the outlet of the primary compressor is respectively connected with the inlet of the water-cooled condenser and the inlet of the air-cooled condenser;
and the outlet of the secondary compressor is respectively connected with the inlet of the water-cooled condenser and the inlet of the air-cooled condenser.
3. A direct-expansion air conditioning unit according to claim 2, characterized by further comprising:
and the electromagnetic valve is arranged between the inlet of the air-cooled condenser and the exhaust outlets of the primary compressor and the secondary compressor.
4. A direct-expansion air conditioning unit according to claim 1, characterized by further comprising:
the main electronic expansion valve is arranged between the outlet of the water-cooled condenser and the inlets of the first-stage evaporator and the second-stage evaporator;
the auxiliary electronic expansion valve is arranged between the outlet of the air-cooled condenser and the inlets of the first-stage evaporator and the second-stage evaporator.
5. A direct-expansion air conditioning unit according to claim 2, characterized by further comprising:
a primary gas-liquid separator and a secondary gas-liquid separator;
the first-stage gas-liquid separator is arranged between an inlet of the first-stage compressor and an outlet of the first-stage evaporator;
the second-stage gas-liquid separator is arranged between an inlet of the second-stage compressor and an outlet of the second-stage evaporator.
6. A direct-expansion air conditioning unit according to claim 1, characterized by further comprising:
the evaporation area of the first-stage evaporator is larger than that of the second-stage evaporator.
7. A direct expansion type air conditioning unit control method applied to the direct expansion type air conditioning unit according to any one of claims 1 to 6, comprising:
acquiring air conditioner operation parameters;
controlling the opening degree of a main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters;
and/or the presence of a gas in the gas,
and controlling the opening of an auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air-conditioner operation parameters.
8. The direct-expansion air conditioning unit control method according to claim 7, wherein the air conditioning operation parameters include:
at least one of the outlet air temperature, outlet air humidity, return air temperature and suction superheat degree.
9. The direct-expansion air conditioning unit control method according to claim 8, further comprising:
calculating the outlet air moisture content according to the outlet air temperature and the outlet air humidity;
and when the outlet air moisture content is greater than the target outlet air moisture content set value, controlling the primary compressor to be started.
10. The direct-expansion air conditioning unit control method according to claim 9, wherein the calculating of the outlet air moisture content from the outlet air temperature and the outlet air humidity includes:
inputting the outlet air temperature into an empirical formula to calculate the outlet air moisture content, wherein the empirical formula is as follows:
d1＝622*{RH4*133exp[18.5916-3991.11/(T4+233.84)]}/{101300-RH4*133exp[18.5916-3991.11/(T4+233.84)]}
wherein d1 is the outlet air moisture content, T4 is the outlet air temperature, and RH4 is the outlet air humidity.
11. The direct-expansion air conditioning unit control method according to claim 8, further comprising:
and controlling the state of an electromagnetic valve according to the comparison result of the return air temperature and the return air temperature set value, wherein the electromagnetic valve is arranged between the inlet of the air-cooled condenser and the exhaust outlets of the primary compressor and the secondary compressor and is used for controlling the on-off of the inlet passage of the air-cooled condenser.
12. The direct-expansion air conditioning unit control method according to claim 11, wherein the controlling for controlling the state of the solenoid valve according to the comparison result of the return air temperature with the return air temperature set value comprises:
if the return air temperature is less than the set return air temperature value, controlling the electromagnetic valve to open;
and if the return air temperature is not less than the set return air temperature value and the opening degree of the auxiliary electronic expansion valve is opened to the minimum step number, controlling the electromagnetic valve to be closed.
13. The direct expansion air conditioning unit control method according to claim 8, wherein the controlling of the opening of the auxiliary electronic expansion valve for adjusting the flow rate of the refrigerant passing through the air-cooled condenser according to the air conditioning operation parameter includes:
if the return air temperature is more than or equal to T-1, controlling the opening of the auxiliary electronic expansion valve to be reduced;
if the T-delta T-1 is greater than the return air temperature and less than T-1, controlling the opening of the auxiliary electronic expansion valve to be unchanged;
if the return air temperature is less than or equal to T-delta T-1, controlling the opening of the auxiliary electronic expansion valve to be increased;
wherein T is the return air temperature target value, and Delta T is the difference value of the return air temperature and the return air temperature target value.
14. The direct-expansion air conditioning unit control method according to claim 9, characterized by further comprising:
and when the frequency of the first-stage compressor reaches the maximum frequency set value, controlling the second-stage compressor to be started.
15. The direct-expansion air conditioning unit control method according to claim 14, wherein the controlling of the opening degree of a main electronic expansion valve for adjusting the flow rate of refrigerant passing through the water-cooled condenser according to the air conditioning operation parameter includes:
after the secondary compressor is started, the opening degree of the main electronic expansion valve is adjusted according to the deviation between the suction superheat degree and the target suction superheat degree set value.
16. The direct expansion type air conditioning unit control method according to claim 15, wherein the adjusting the opening degree of the main electronic expansion valve includes:
if the deviation of the suction superheat degree is larger than the target suction superheat degree set value, controlling the opening of the main electronic expansion valve to be increased;
if the suction superheat deviation is more than 0 and less than or equal to the target suction superheat set value, controlling the opening of the main electronic expansion valve to be unchanged;
and if the deviation of the suction superheat degree is less than or equal to 0, controlling the opening degree of the auxiliary electronic expansion valve to be reduced.
17. The direct-expansion air conditioning unit control method according to claim 9 or 10, characterized by further comprising:
and adjusting the frequency of a compressor according to the air outlet moisture content, wherein the compressor comprises a primary compressor and/or a secondary compressor.
18. The direct-expansion air conditioning unit control method according to claim 17, wherein the adjusting the frequency of the compressor according to the outlet air moisture content includes:
if d1 is greater than dcm, controlling the frequency of the compressor to increase according to a first time interval;
if the dcm is more than or equal to d1 and is more than the dcm-dcm, controlling the frequency of the compressor to keep unchanged;
if the dcm-dcmp-1 is more than or equal to d1 and more than the dcm-dcmp-2, controlling the frequency of the compressor to be reduced according to a second time interval until the detected frequency is the lowest frequency;
and d1 is the outlet air moisture content, dcm is the target outlet air moisture content set value, and dcmp is the difference between the outlet air moisture content and the target outlet air moisture content set value.
19. A direct expansion type air conditioning unit control device is characterized by comprising:
the acquisition module is used for acquiring the operating parameters of the air conditioner;
the control module is used for controlling the opening of a main electronic expansion valve used for adjusting the flow of the refrigerant passing through the water-cooled condenser according to the air conditioner operation parameters;
and/or the presence of a gas in the gas,
and controlling the opening of an auxiliary electronic expansion valve for adjusting the flow of the refrigerant passing through the air-cooled condenser according to the air-conditioner operation parameters.
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