CN116294102A - Central air conditioner cooling water supply and return water temperature difference optimal control system and method - Google Patents

Central air conditioner cooling water supply and return water temperature difference optimal control system and method Download PDF

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CN116294102A
CN116294102A CN202310128037.1A CN202310128037A CN116294102A CN 116294102 A CN116294102 A CN 116294102A CN 202310128037 A CN202310128037 A CN 202310128037A CN 116294102 A CN116294102 A CN 116294102A
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temperature difference
temperature
water supply
water
cooling water
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高佳佳
高亮
彭绮娴
刘雅琴
熊琬钰
汤立宽
李冠男
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Wuhan University of Science and Engineering WUSE
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Wuhan University of Science and Engineering WUSE
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
    • F24F11/63—Electronic processing
    • F24F11/64—Electronic processing using pre-stored data
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
    • F24F11/46—Improving electric energy efficiency or saving
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F11/00—Control or safety arrangements
    • F24F11/70—Control systems characterised by their outputs; Constructional details thereof
    • F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
    • F24F11/83—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers
    • F24F11/85—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling the supply of heat-exchange fluids to heat-exchangers using variable-flow pumps
    • 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

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Abstract

The invention relates to a central air conditioner cooling water supply and return water temperature difference optimization control system and method, comprising a cooling tower, a cooling water pump provided with a frequency converter, a water loop formed by sequentially connecting a water chilling unit condenser and a controller for controlling the supply and return water temperature difference, wherein the cooling tower is communicated with the cooling water pump and the cooling water pump is communicated with the water chilling unit condenser through a water return pipe, the water chilling unit condenser is communicated with the cooling tower through a water supply pipe, a first temperature sensor and a second temperature sensor are respectively arranged on the water return pipe and the water supply pipe, and the frequency converter, the first temperature sensor and the second temperature sensor are respectively electrically connected with the controller. The controller calculates the optimized temperature difference set value through respectively collecting the water supply temperature signal and the backwater temperature signal, and calculates the working frequency of the frequency converter so as to control the rotating speed of the cooling water pump, dynamically adjust the temperature difference between the water supply temperature and the backwater temperature to the optimized temperature difference set value, and improve the accuracy and the reliability of the calculation of the temperature difference set value.

Description

Central air conditioner cooling water supply and return water temperature difference optimal control system and method
Technical Field
The invention relates to the technical field of building energy conservation and refrigeration air conditioner control, in particular to a central air conditioner cooling water supply and return water temperature difference optimization control system and a control method.
Background
Most of the time the central air conditioning system is operated under partial load, and most of the water flow of the cooling water system is in a state of abundance. The variable flow control is implemented on the cooling water system, so that the running energy consumption of the cooling water pump can be effectively reduced. The variable flow control of the cooling water system usually adopts temperature difference control, namely, the operation frequency of the cooling water pump is regulated according to the temperature difference of the cooling water supply and return water, and the temperature difference of the cooling water supply and return water is maintained at 4-5 ℃. Typically the cooling water return design temperature is 32 ℃ and the water supply design temperature is 37 ℃. When the outdoor temperature is higher, the backwater temperature of the cooling water is always higher than the designed temperature of 32 ℃, and the backwater temperature is kept continuously at the moment, and when the fixed temperature difference of 5 ℃ is controlled, the water supply temperature of the cooling water can exceed 37 ℃ and even reach 40 ℃, so that the running efficiency of the water chilling unit can be reduced, and the high-temperature alarm of the water chilling unit can be triggered, so that the water chilling unit is down. Therefore, the cooling effect of the system is affected, and great potential safety hazards exist. In practical engineering application, in order to ensure safe operation of the water chilling unit, many engineers often adopt low temperature difference set values (such as 3 ℃ temperature difference) to control the cooling water pump, so that energy consumption waste of the cooling water pump is greatly increased. Therefore, optimizing the temperature difference control strategy of the central air-conditioning cooling water system has important significance for improving the operation safety of the central air-conditioning system and reducing the operation energy consumption of the system.
In view of the technical background, the existing variable frequency control system of the cooling water pump of the central air conditioner has the problems that the temperature difference is fixed, when the outdoor temperature is higher, the water supply temperature of the cooling water is too high, and the high-temperature alarm downtime of the water chilling unit is caused, so that the energy-saving operation of the system is affected, and the system has great potential safety hazard and cannot fully meet the requirements of building safety, energy conservation and consumption reduction.
Disclosure of Invention
The invention aims to solve the technical problems of the prior art, and provides a central air conditioner cooling water supply and return water temperature difference optimization control system and method.
The technical scheme for solving the technical problems is as follows: the utility model provides a central air conditioning cooling water supplies return water difference in temperature optimization control system, includes by cooling tower, the cooling water pump that disposes the converter, the cooling water set condenser link to each other in order and form the water return circuit and be used for controlling and supply return water difference in temperature's controller, between cooling tower and the cooling water pump and between cooling water pump and the cooling water set condenser through the wet return intercommunication, between cooling water set condenser and the cooling tower through the delivery pipe intercommunication, be provided with first temperature sensor and second temperature sensor on wet return and the delivery pipe respectively, converter, first temperature sensor and second temperature sensor respectively with the controller electricity is connected;
the first temperature sensor and the second temperature sensor are respectively used for collecting a water supply temperature signal of water supply in the water return pipe and water return temperature signals in the water supply pipe;
the controller is used for calculating an optimized temperature difference set value according to the water supply temperature signal and the water return temperature signal, calculating a real-time cooling water supply and water return temperature difference according to the water supply temperature signal and the water return temperature signal, judging whether the cooling water supply and water return temperature difference is within the deviation range of the optimized temperature difference set value, if so, controlling the working frequency of the cooling water pump to maintain the last output value unchanged, otherwise, comparing the cooling water supply and water return temperature difference with the optimized temperature difference set value, calculating the working frequency of the frequency converter, and outputting the frequency converter;
the frequency converter controls the rotating speed of the cooling water pump according to the working frequency, and adjusts the temperature difference between the temperature of water supply in the water return pipe and the temperature of water supply in the water supply pipe to the optimized temperature difference set value.
The beneficial effects of the invention are as follows: according to the central air conditioner cooling water supply and return water temperature difference optimal control system, the first temperature sensor and the second temperature sensor are used for respectively collecting the water supply temperature signal and the return water temperature signal, the controller is used for calculating the optimal temperature difference set value, and further calculating the working frequency of the frequency converter, so that the rotating speed of the cooling water pump is controlled, the temperature difference between the water supply temperature in the return water pipe and the water supply temperature in the water supply pipe is dynamically adjusted to the optimal temperature difference set value, the accuracy and the reliability of temperature difference set value calculation are improved, the optimal temperature difference set value of cooling water supply and return water can be automatically adjusted along with the real-time cooling water supply temperature and return water temperature change, the degree of automation of the whole system is improved, the response time of the system to environmental change is reduced, the energy consumption of the system is reduced while the safe and stable operation of the system is ensured, and the energy-saving operation of the central air conditioner cooling water system is realized.
Based on the technical scheme, the invention can also be improved as follows:
further: the controller calculates and optimizes the specific realization of the temperature difference set value according to the water supply temperature signal and the backwater temperature signal:
if T is defined 2 To supply water temperature for real-time cooling water, T 1 For the real-time return water temperature of the cooling water,
Figure BDA0004082820100000031
to optimize the temperature difference set point, deltaT set For default temperature difference set value, T 2，up The upper limit value of the water supply temperature of the cooling water is set, and the water supply temperature does not exceed the high-temperature alarm temperature;
the calculation formula of the optimized temperature difference set value is as follows:
if T 2 ＞T 2，up Then
Figure BDA0004082820100000032
If T 2 ≤T 2，up And T is 1 +ΔT set ＞T 2，up Then
Figure BDA0004082820100000033
If T 2 ≤T 2，up And T is 1 +ΔT set ≤T 2，up Then
Figure BDA0004082820100000034
The beneficial effects of the above-mentioned further scheme are: when the temperature value T of the water supply of the real-time cooling water 2 Is higher than the upper limit value T of the water supply temperature of the cooling water 2，up When optimizing the temperature difference set value
Figure BDA0004082820100000035
Along with the real-time return water temperature value T of cooling water 1 Is changed according to the change of the temperature T of the return water of the real-time cooling water 1 Rising, optimizing the temperature difference set value ∈>
Figure BDA0004082820100000036
Reducing the temperature value T of the return water of the real-time cooling water 1 Reducing and optimizing the temperature difference set value->
Figure BDA0004082820100000037
An increase; when the real-time cooling water supply temperature T 2 Is less than or equal to the upper limit value T of the water supply temperature of the cooling water 2，up When the temperature T of the return water of the real-time cooling water needs to be further judged 1 With a default temperature difference set point DeltaT set The sum is larger than the upper limit value T of the water supply temperature of the cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000038
Also set upper limit value T of water supply temperature of cooling water 2，up And the return water temperature of the real-time cooling waterDegree T 1 A difference between; when the real-time cooling water backwater temperature T 1 With a default temperature difference set point DeltaT set The sum is less than or equal to the upper limit value T of the water supply temperature of the cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000041
Is a default temperature difference set value delta T set 。
Further: the range of the optimized temperature difference set value is between an upper temperature difference limit value and a lower temperature difference limit value, when the optimized temperature difference set value calculated by the controller is larger than the upper temperature difference limit value, the optimized temperature difference set value is determined to be equal to the upper temperature difference limit value, and when the optimized temperature difference set value calculated by the controller is smaller than the lower temperature difference limit value, the optimized temperature difference set value is determined to be equal to the lower temperature difference limit value.
The beneficial effects of the above-mentioned further scheme are: by controlling the upper limit value of the temperature difference of the optimized temperature difference set value to the lower limit value of the temperature difference, a certain safety margin can be reserved, so that the safety and stability of the whole system can be ensured
The invention also provides a central air conditioner cooling water supply and return water temperature difference optimal control method, which adopts the central air conditioner cooling water supply and return water temperature difference optimal control system and comprises the following steps:
collecting a water supply temperature signal of water supply in the water return pipe and water return temperature signals in a water supply pipe respectively;
calculating an optimized temperature difference set value according to the water supply temperature signal and the backwater temperature signal;
calculating a real-time cooling water supply and return water temperature difference according to the water supply temperature signal and the return water temperature signal, judging whether the cooling water supply and return water temperature difference is within the deviation range of the optimized temperature difference set value, if so, controlling the working frequency of the cooling water pump to maintain the last output value unchanged, otherwise, comparing the cooling water supply and return water temperature difference with the optimized temperature difference set value, and determining the working frequency of the frequency converter;
and the frequency converter controls the rotating speed of the cooling water pump according to the working frequency, and adjusts the temperature difference between the temperature of the water supply in the water return pipe and the temperature of the water supply in the water supply pipe to the optimized temperature difference set value.
According to the central air conditioner cooling water supply and return water temperature difference optimization control method, the water supply temperature signal and the return water temperature signal are respectively acquired, the optimized temperature difference set value is calculated, and the working frequency of the frequency converter is further calculated, so that the rotating speed of the cooling water pump is controlled, the temperature difference between the water supply temperature in the return water pipe and the water supply temperature in the water supply pipe is dynamically adjusted to the optimized temperature difference set value, the accuracy and the reliability of calculation of the temperature difference set value are improved, the optimized temperature difference set value of the cooling water supply and return water can be automatically adjusted along with the real-time cooling water supply temperature and return water temperature change, the automation degree of the whole system is improved, the response time of the system to environmental change is reduced, the energy consumption of the system can be reduced while the safe and stable operation of the system is ensured, and the energy-saving operation of the central air conditioner cooling water system is realized.
Based on the technical scheme, the invention can also be improved as follows:
further: the method for calculating the optimal temperature difference set value according to the water supply temperature signal and the backwater temperature signal specifically comprises the following steps:
if T is defined 2 To supply water temperature for real-time cooling water, T 1 For the real-time return water temperature of the cooling water,
Figure BDA0004082820100000051
to optimize the temperature difference set point, deltaT set For default temperature difference set value, T 2，up The upper limit value of the water supply temperature of the cooling water is set, and the water supply temperature does not exceed the high-temperature alarm temperature;
the calculation formula of the optimized temperature difference set value is as follows:
if T 2 ＞T 2，up Then
Figure BDA0004082820100000052
If T 2 ≤T 2，up And T is 1 +ΔT set ≥T 2，up Then
Figure BDA0004082820100000053
If T 2 ≤T 2，up And T is 1 +ΔT set ≤T 2，up Then
Figure BDA0004082820100000054
The beneficial effects of the above-mentioned further scheme are: when the temperature value T of the water supply of the real-time cooling water 2 Is higher than the upper limit value T of the water supply temperature of the cooling water 2，up When optimizing the temperature difference set value
Figure BDA0004082820100000055
Along with the real-time return water temperature value T of cooling water 1 Is changed according to the change of the temperature T of the return water of the real-time cooling water 1 Rising, optimizing the temperature difference set value ∈>
Figure BDA0004082820100000056
Reducing the temperature value T of the return water of the real-time cooling water 1 Reducing and optimizing the temperature difference set value->
Figure BDA0004082820100000057
An increase; when the real-time cooling water supply temperature T 2 Is less than or equal to the upper limit value T of the water supply temperature of the cooling water 2，up When the temperature T of the return water of the real-time cooling water needs to be further judged 1 With a default temperature difference set point DeltaT set The sum is larger than the upper limit value T of the water supply temperature of the cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000058
Also set upper limit value T of water supply temperature of cooling water 2，up And the real-time cooling water backwater temperature T 1 A difference between; when the real-time cooling water backwater temperature T 1 With a default temperature difference set point DeltaT set The sum of the cooling water supply and the water supply is less than or equal to the set cooling water supplyUpper limit value T of temperature 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000061
Is a default temperature difference set value delta T set 。
Further: the range of the optimized temperature difference set value is between an upper temperature difference limit value and a lower temperature difference limit value, when the optimized temperature difference set value calculated by the controller is larger than the upper temperature difference limit value, the optimized temperature difference set value is determined to be equal to the upper temperature difference limit value, and when the optimized temperature difference set value calculated by the controller is smaller than the lower temperature difference limit value, the optimized temperature difference set value is determined to be equal to the lower temperature difference limit value.
The beneficial effects of the above-mentioned further scheme are: by controlling the upper limit value of the temperature difference of the optimized temperature difference set value to the lower limit value of the temperature difference, a certain safety margin can be reserved, so that the safety and stability of the whole system can be ensured.
The invention also provides a computer readable storage medium, wherein the computer readable storage medium stores computer instructions, and the computer instructions are used for realizing the central air conditioner cooling water supply and return water temperature difference optimization control method when being executed by a processor.
The invention also provides a central air conditioner cooling water supply and return water temperature difference optimal control device, which comprises:
at least one processor and a storage medium, the memory communicatively coupled to the processor;
wherein the storage medium stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor, so that the at least one processor can execute the central air-conditioning cooling water supply and return water temperature difference optimizing control method.
Drawings
FIG. 1 is a schematic diagram of a system for optimizing and controlling the temperature difference of cooling water supply and return water of a central air conditioner according to an embodiment of the invention;
FIG. 2 is a graph of an optimized temperature differential limiting range according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a method for optimizing and controlling the temperature difference of cooling water supply and return water of a central air conditioner according to an embodiment of the invention.
In the drawings, the list of components represented by the various numbers is as follows:
1. a cooling tower; 2. a water return pipe; 3. a cooling water pump; 4. a condenser of the chiller; 5. a water supply pipe; 6. a frequency converter; 7. a controller; 8. a first temperature sensor; 9. and a second temperature sensor.
Detailed Description
The principles and features of the present invention are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the invention and are not to be construed as limiting the scope of the invention.
As shown in fig. 1, the central air conditioner cooling water supply and return water temperature difference optimization control system comprises a cooling tower 1, a cooling water pump 3 provided with a frequency converter 6, a water loop formed by sequentially connecting a water chilling unit condenser 4 and a controller 7 for controlling the supply and return water temperature difference, wherein the cooling tower 1 and the cooling water pump 3 and the water chilling unit condenser 4 are communicated through a water return pipe 2, the water chilling unit condenser 4 and the cooling tower 1 are communicated through a water supply pipe 5, a first temperature sensor 8 and a second temperature sensor 9 are respectively arranged on the water return pipe 2 and the water supply pipe 5, and the frequency converter 6, the first temperature sensor 8 and the second temperature sensor 9 are respectively electrically connected with the controller 7;
the first temperature sensor 8 and the second temperature sensor 9 are respectively used for collecting a water supply temperature signal of water supply in the water return pipe 2 and a water return and water return temperature signal in the water supply pipe 5;
the controller 7 is used for calculating an optimized temperature difference set value according to the water supply temperature signal and the backwater temperature signal, and calculating the working frequency of the frequency converter 6 according to the optimized temperature difference set value;
the frequency converter 6 controls the rotation speed of the cooling water pump 3 according to the working frequency, and adjusts the temperature difference between the temperature of the water supply in the water return pipe 2 and the temperature of the water supply in the water supply pipe 5 to the optimized temperature difference set value.
According to the central air conditioner cooling water supply and return water temperature difference optimization control system, the water supply temperature signal and the return water temperature signal are respectively acquired through the first temperature sensor 8 and the second temperature sensor 9, the optimized temperature difference set value is calculated by the controller 7, and the working frequency of the frequency converter 6 is further calculated, so that the rotating speed of the cooling water pump 3 is controlled, the temperature difference between the water supply temperature in the return water pipe 2 and the water supply temperature in the water supply pipe 5 is dynamically adjusted to the optimized temperature difference set value, the accuracy and the reliability of calculation of the temperature difference set value are improved, the optimized temperature difference set value of the cooling water supply and return water can be automatically adjusted along with the real-time change of the cooling water supply temperature and the return water temperature, the automation degree of the whole system is improved, the response time of the system to environmental change is reduced, the safe and stable operation of the system is ensured, the energy consumption of the system is reduced, and the energy-saving operation of the central air conditioner cooling water system is realized.
Here, the frequency converter 6 sets a frequency according to the calculated working frequency value, adjusts the rotation speed of the cooling water pump 3, and then adjusts the temperature difference between the water supply pipe 5 and the water return pipe 2, so as to maintain the temperature difference set value to ensure that the water supply temperature of the cooling water is always lower than the high-temperature alarm temperature of the water chilling unit, and further ensure the safe operation of the water chilling unit, and meanwhile, the cooling water pump 3 operates at the lowest energy consumption in a safe range, and further saves energy.
In one or more embodiments of the present invention, the controller 7 includes a calculation module and a variable frequency control module;
the calculation module is used for calculating an optimized temperature difference set value according to the water supply temperature signal and the backwater temperature signal and transmitting the optimized temperature difference set value to the frequency conversion control module;
the frequency conversion control module is configured to calculate a real-time cooling water supply and return water temperature difference according to the water supply temperature signal and the return water temperature signal, determine whether the cooling water supply and return water temperature difference is within a deviation range of the optimized temperature difference set value, if so, control the working frequency of the cooling water pump 3 to maintain the last output value unchanged, otherwise, compare the cooling water supply and return water temperature difference with the optimized temperature difference set value, calculate the working frequency of the frequency converter 6, and output the working frequency to the frequency converter 6.
The calculation module calculates an optimized temperature difference set value according to the water supply temperature signal and the water return temperature signal, and the variable frequency control module calculates a real-time cooling water supply and return temperature difference according to the water supply temperature signal and the water return temperature signal, so that the working frequency of the frequency converter 6 can be accurately calculated according to comparison between the real-time cooling water supply and return temperature difference and the optimized temperature difference set value, the rotating speed of the cooling water pump 3 can be controlled, and the cooling water supply and return temperature difference can be dynamically adjusted to the optimized temperature difference set value more conveniently than the price.
In one or more embodiments of the present invention, the controller 7 calculates the optimized temperature difference set point according to the water supply temperature signal and the backwater temperature signal by:
if T is defined 2 To supply water temperature for real-time cooling water, T 1 For the real-time return water temperature of the cooling water,
Figure BDA0004082820100000091
to optimize the temperature difference set point, deltaT set For default temperature difference set value, T 2，up The upper limit value of the water supply temperature of the cooling water is set, and the water supply temperature does not exceed the high-temperature alarm temperature;
the calculation formula of the optimized temperature difference set value is as follows:
if T 2 ＞T 2，up Then
Figure BDA0004082820100000092
If T 2 ≤T 2，up And T is 1 +ΔT set ＞T 2，up Then
Figure BDA0004082820100000093
If T 2 ≤T 2，up And T is 1 +ΔT set ≤T 2，up Then
Figure BDA0004082820100000094
When the temperature value T of the water supply of the real-time cooling water 2 Is higher than the upper limit value T of the water supply temperature of the cooling water 2，up When optimizing the temperature difference set value
Figure BDA0004082820100000095
Along with the real-time return water temperature value T of cooling water 1 Is changed according to the change of the temperature T of the return water of the real-time cooling water 1 Rising, optimizing the temperature difference set value ∈>
Figure BDA0004082820100000096
Reducing the temperature value T of the return water of the real-time cooling water 1 Reducing and optimizing the temperature difference set value->
Figure BDA0004082820100000097
An increase; when the real-time cooling water supply temperature T 2 Is less than or equal to the upper limit value T of the water supply temperature of the cooling water 2，up When the temperature T of the return water of the real-time cooling water needs to be further judged 1 With a default temperature difference set point DeltaT set The sum is larger than the upper limit value T of the water supply temperature of the cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000098
Also set upper limit value T of water supply temperature of cooling water 2，up And the real-time cooling water backwater temperature T 1 A difference between; when the real-time cooling water backwater temperature T 1 With a default temperature difference set point DeltaT set The sum is less than or equal to the upper limit value T of the water supply temperature of the cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000099
Is a default temperature difference set value delta T set 。
In practice, the default temperature difference set value is generally 5 ℃, the high-temperature alarm temperature is generally more than 38 ℃, and a certain safety margin is reserved for T in the algorithm 2，up Default settingsAnd calculating at 37.5 ℃ according to the algorithm model to obtain an optimized temperature difference set value.
In order to adjust the temperature difference between the water supply temperatures to the optimized temperature difference set point, in the embodiment of the present invention, the operating frequency of the frequency converter 6 is calculated using a PID algorithm.
In one or more embodiments of the present invention, the optimized temperature difference set value ranges from an upper temperature difference limit value to a lower temperature difference limit value, when the optimized temperature difference set value calculated by the controller 7 is greater than the upper temperature difference limit value, the optimized temperature difference set value is determined to be equal to the upper temperature difference limit value, and when the optimized temperature difference set value calculated by the controller 7 is less than the lower temperature difference limit value, the optimized temperature difference set value is determined to be equal to the lower temperature difference limit value. By controlling the upper limit value of the temperature difference of the optimized temperature difference set value to the lower limit value of the temperature difference, a certain safety margin can be reserved, so that the safety and stability of the whole system can be ensured. In the embodiment of the invention, the upper limit value of the temperature difference is 5-7 ℃; the lower limit value of the temperature difference is 2-3 ℃.
As shown in fig. 2, a central air conditioner cooling water supply and return water temperature difference optimizing control method, which adopts the central air conditioner cooling water supply and return water temperature difference optimizing control system, comprises the following steps:
s1: collecting a water supply temperature signal of water supply in the water return pipe 2 and a water return and water return temperature signal in the water supply pipe 5 respectively;
s2: calculating an optimized temperature difference set value according to the water supply temperature signal and the backwater temperature signal;
s3: calculating a real-time cooling water supply and return water temperature difference according to the water supply temperature signal and the return water temperature signal number, judging whether the cooling water supply and return water temperature difference is within the deviation range of the optimized temperature difference set value, if so, controlling the working frequency of the cooling water pump 3 to maintain the last output value unchanged, otherwise, comparing the cooling water supply and return water temperature difference with the optimized temperature difference set value, and determining the working frequency of the frequency converter 6;
s4: the frequency converter 6 controls the rotation speed of the cooling water pump 3 according to the working frequency, and adjusts the temperature difference between the water supply temperature in the water return pipe 2 and the water supply temperature in the water supply pipe 5 to the optimized temperature difference set value.
According to the central air conditioner cooling water supply and return water temperature difference optimal control method, the water supply temperature signal and the water return temperature signal are respectively acquired, the optimal temperature difference set value is calculated, and the working frequency of the frequency converter 6 is further calculated, so that the rotating speed of the cooling water pump 3 is controlled, the temperature difference between the water supply temperature in the water return pipe 2 and the water supply temperature in the water supply pipe 5 is dynamically adjusted to the optimal temperature difference set value, the accuracy and the reliability of calculation of the temperature difference set value are improved, the optimal temperature difference set value of the cooling water supply and return water can be automatically adjusted along with the real-time cooling water supply temperature and return water temperature change, the degree of automation of the whole system is improved, the response time of the system to environmental change is reduced, the energy consumption of the system can be reduced while the safe and stable operation of the system is ensured, and the energy-saving operation of the central air conditioner cooling water system is realized.
In one or more embodiments of the invention, the deviation of the optimized temperature difference setpoint ranges between ±0.2 ℃ of the optimized temperature difference setpoint.
In one or more embodiments of the present invention, the calculating the optimized temperature difference set point according to the water supply temperature signal and the water return temperature signal specifically includes the following steps:
if T is defined 2 To supply water temperature for real-time cooling water, T 1 For the real-time return water temperature of the cooling water,
Figure BDA0004082820100000111
to optimize the temperature difference set point, deltaT set For default temperature difference set value, T 2，up The upper limit value of the water supply temperature of the cooling water is set, and the water supply temperature does not exceed the high-temperature alarm temperature;
the calculation formula of the optimized temperature difference set value is as follows:
if T 2 ＞T 2，up Then
Figure BDA0004082820100000112
If T 2 ≤T 2，up And T is 1 +ΔT set ＞T 2，up Then
Figure BDA0004082820100000113
If T 2 ≤T 2，up And T is 1 +ΔT set ≤T 2，up Then
Figure BDA0004082820100000114
When the temperature value T of the water supply of the real-time cooling water 2 Is higher than the upper limit value T of the water supply temperature of the cooling water 2，up When optimizing the temperature difference set value
Figure BDA0004082820100000115
Along with the real-time return water temperature value T of cooling water 1 Is changed according to the change of the temperature T of the return water of the real-time cooling water 1 Rising, optimizing the temperature difference set value ∈>
Figure BDA0004082820100000116
Reducing the temperature value T of the return water of the real-time cooling water 1 Reducing and optimizing the temperature difference set value->
Figure BDA0004082820100000117
An increase; when the real-time cooling water supply temperature T 2 Is less than or equal to the upper limit value T of the water supply temperature of the cooling water 2，up When the temperature T of the return water of the real-time cooling water needs to be further judged 1 With a default temperature difference set point DeltaT set The sum is larger than the upper limit value T of the water supply temperature of the cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000118
Also set upper limit value T of water supply temperature of cooling water 2，up And the real-time cooling water backwater temperature T 1 A difference between; when the real-time cooling water backwater temperature T 1 With a default temperature difference set point DeltaT set The sum is less than or equal toUpper limit value T of water supply temperature of cooling water 2，up Optimizing the temperature difference set value +.>
Figure BDA0004082820100000119
Is a default temperature difference set value delta T set 。
In one or more embodiments of the present invention, the optimized temperature difference set value ranges from an upper temperature difference limit value to a lower temperature difference limit value, when the optimized temperature difference set value calculated by the controller 7 is greater than the upper temperature difference limit value, the optimized temperature difference set value is determined to be equal to the upper temperature difference limit value, and when the optimized temperature difference set value calculated by the controller 7 is less than the lower temperature difference limit value, the optimized temperature difference set value is determined to be equal to the lower temperature difference limit value. By controlling the upper limit value of the temperature difference of the optimized temperature difference set value to the lower limit value of the temperature difference, a certain safety margin can be reserved, so that the safety and stability of the whole system can be ensured.
For example, the optimized temperature difference set point has a certain interval range. When the calculated optimal temperature difference set value is higher than the set upper limit value, for example, 7 ℃, outputting the optimal temperature difference set value by the upper limit value; and when the calculated optimal temperature difference set value is lower than the set lower limit value, for example, 2 ℃, outputting the optimal temperature difference set value with the lower limit value.
In the embodiment of the invention, the temperature difference of the cooling water supply and return water is compared with the optimized temperature difference set value, and the working frequency of the frequency converter 6 is determined by adopting a PID algorithm, specifically:
when the real-time cooling water supply and return water temperature difference is larger than the calculated optimal temperature difference set value, the PID algorithm calculates a larger working frequency value of the cooling water pump 3 after optimization according to the deviation value, and then sends a working frequency signal to the frequency converter 6 so as to increase the rotating speed of the cooling water pump 3 and further reduce the cooling water supply and return water temperature difference; when the real-time cooling water supply and return water temperature difference is smaller than the calculated optimal temperature difference set value, the PID algorithm calculates the optimized working frequency value of the smaller cooling water pump 3 according to the deviation value, and then sends the optimized working frequency signal to the frequency converter 6 so as to reduce the rotating speed of the cooling water pump 3 and further increase the cooling water supply and return water temperature difference.
The frequency control dead zone is set in the process control algorithm, the general dead zone range is-0.2 ℃ to 0.2 ℃, namely, when the deviation between the detected cooling water supply and return water temperature difference and the optimized temperature difference set value is between-0.2 ℃ to 0.2 ℃, the PID algorithm does not calculate, and the working frequency of the cooling water pump 3 is kept unchanged at the last moment.
The PID algorithm adopted by the process control algorithm in the present invention is a common algorithm, and the specific algorithm formula is not the content of the present invention, so the detailed description is not repeated.
Through the control system and the control method, the cooling water supply and return water temperature difference control is to control the working frequency of the cooling water pump according to the optimized cooling water supply and return water temperature difference set value and the system real-time cooling water supply and return water temperature difference, so that the cooling water pump 3 operates in an optimized working frequency state, the system energy consumption can be reduced while the safe and stable operation of the system is ensured, the energy-saving operation of the central air conditioner cooling water system is realized, and the intelligent operation degree of the cooling water system is effectively improved.
FIG. 3 is a graph of the optimized temperature difference limit, with the optimized temperature difference set point being defined at 2-7deg.C and the cooling water supply temperature being defined at no more than 37.5deg.C.
The invention provides a control system and a control method thereof, wherein an intelligent controller is arranged in the control system, the controller comprises two modules, and the safe and reliable performance of the intelligent controller can be fully utilized by adopting a layered design mode of a control strategy, so that the energy-saving operation of the system can be realized, and the reliability and safety of the system in operation are ensured.
In the embodiment of the invention, the temperature difference of the cooling water supply and return water is not a fixed value, but is calculated by a corresponding algorithm, so that the accuracy and reliability of the calculation of the temperature difference set value of the cooling water supply and return water are improved. The optimal temperature difference set value of the cooling water supply and return water can be automatically adjusted along with the real-time change of the cooling water supply temperature and return water temperature, so that the automation degree of the whole system is improved, and the response time of the system to environmental change is reduced. And the working frequency of the cooling water pump 3 is calculated by a calculation module in the controller 7 and is sent to the frequency converter 6, the working frequency of the cooling water pump 3 is adjusted according to the working frequency, the safe and stable operation of the system is ensured, the energy consumption of the system is reduced, and the energy-saving operation of the cooling water system of the central air conditioner is realized.
The optimization control method for the temperature difference of the cooling water supply and return water of the central air conditioner can effectively improve the safety and stability of system operation, save the energy consumption of system operation, solve the problem that when the outdoor temperature is higher, the cooling water unit is down due to high temperature of the cooling water supply, and solve the problem that the energy saving effect of a cooling water system is poor due to equipment failure avoidance.
The invention also provides a computer readable storage medium, wherein the computer readable storage medium stores computer instructions, and the computer instructions are used for realizing the central air conditioner cooling water supply and return water temperature difference optimal control method when being executed by a processor.
The invention also provides a central air conditioner cooling water supply and return water temperature difference optimal control device, which comprises:
at least one processor and a storage medium, the memory communicatively coupled to the processor;
wherein the storage medium stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor, so that the at least one processor can execute the central air-conditioning cooling water supply and return water temperature difference optimizing control method.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims (8)

1. The utility model provides a central air conditioning cooling water supplies return water difference in temperature optimization control system, its characterized in that includes by cooling tower (1), cooling water pump (3) that dispose converter (6), cooling water set condenser (4) link to each other in order and form water return circuit and be used for controlling supply return water difference in temperature's controller (7), between cooling tower (1) and cooling water pump (3) and between cooling water pump (3) and cooling water set condenser (4) through wet return (2) intercommunication, between cooling water set condenser (4) and cooling tower (1) through delivery pipe (5) intercommunication, be provided with first temperature sensor (8) and second temperature sensor (9) on wet return (2) and delivery pipe (5) respectively, converter (6), first temperature sensor (8) and second temperature sensor (9) respectively with controller (7) electricity is connected;
the first temperature sensor (8) and the second temperature sensor (9) are respectively used for collecting a water supply temperature signal of water supply in the water return pipe (2) and a water return and water return temperature signal in the water supply pipe (5);
the controller (7) is used for calculating an optimized temperature difference set value according to the water supply temperature signal and the water return temperature signal, calculating a real-time cooling water supply and return water temperature difference according to the water supply temperature signal and the water return temperature signal, judging whether the cooling water supply and return water temperature difference is within the deviation range of the optimized temperature difference set value, if so, controlling the working frequency of the cooling water pump (3) to maintain the last output value unchanged, otherwise, comparing the cooling water supply and return water temperature difference with the optimized temperature difference set value, calculating the working frequency of the frequency converter (6), and outputting the working frequency to the frequency converter (6), wherein the upper limit value of the temperature difference of the optimized temperature difference set value is 5-7 ℃; the lower limit value of the temperature difference is 2-3 ℃;
the frequency converter (6) controls the rotating speed of the cooling water pump (3) according to the working frequency, and adjusts the temperature difference between the temperature of water supply in the water return pipe (2) and the temperature of water supply in the water supply pipe (5) to the optimized temperature difference set value.
2. The system for optimizing and controlling the temperature difference of the cooling water supply and return water of the central air conditioner according to claim 1, wherein the controller (7) calculates an optimized temperature difference set value according to the water supply temperature signal and the return water temperature signal, and is specifically realized as follows:
if T is defined 2 To supply water temperature for real-time cooling water, T 1 For the real-time return water temperature of the cooling water,
Figure FDA0004082820090000021
to optimize the temperature difference set point, deltaT set For default temperature difference set value, T 2，up The upper limit value of the water supply temperature of the cooling water is set, and the water supply temperature does not exceed the high-temperature alarm temperature;
the calculation formula of the optimized temperature difference set value is as follows:
if T 2 ＞T 2，up Then
Figure FDA0004082820090000022
If T 2 ≤T 2,up And T is 1 +ΔT set ＞T 2，up Then
Figure FDA0004082820090000023
If T 2 ≤T 2，up And T is 1 +ΔT set ≤T 2，up Then
Figure FDA0004082820090000024
3. The central air conditioner cooling water supply and return water temperature difference optimal control system according to claim 1, wherein: the range of the optimized temperature difference set value is between an upper temperature difference limit value and a lower temperature difference limit value, when the optimized temperature difference set value calculated by the controller (7) is larger than the upper temperature difference limit value, the optimized temperature difference set value is determined to be equal to the upper temperature difference limit value, and when the optimized temperature difference set value calculated by the controller (7) is smaller than the lower temperature difference limit value, the optimized temperature difference set value is determined to be equal to the lower temperature difference limit value.
4. A central air conditioner cooling water supply and return water temperature difference optimal control method, which adopts the central air conditioner cooling water supply and return water temperature difference optimal control system as claimed in any one of claims 1-3, and is characterized by comprising the following steps:
collecting a water supply temperature signal of water supply in the water return pipe (2) and a water return and water return temperature signal in the water supply pipe (5) respectively;
calculating an optimized temperature difference set value according to the water supply temperature signal and the backwater temperature signal;
calculating a real-time cooling water supply and return water temperature difference according to the water supply temperature signal and the return water temperature signal number, judging whether the cooling water supply and return water temperature difference is within the deviation range of the optimized temperature difference set value, if so, controlling the working frequency of the cooling water pump (3) to maintain the last output value unchanged, otherwise, comparing the cooling water supply and return water temperature difference with the optimized temperature difference set value, and determining the working frequency of the frequency converter (6);
the frequency converter (6) controls the rotating speed of the cooling water pump (3) according to the working frequency, and adjusts the temperature difference between the temperature of water supply in the water return pipe (2) and the temperature of water supply in the water supply pipe (5) to the optimized temperature difference set value.
5. The central air conditioner cooling water supply and return water temperature difference optimal control system according to claim 4, wherein: the method for calculating the optimal temperature difference set value according to the water supply temperature signal and the backwater temperature signal specifically comprises the following steps:
if T is defined 2 To supply water temperature for real-time cooling water, T 1 For the real-time return water temperature of the cooling water,
Figure FDA0004082820090000031
to optimize the temperature difference set point, deltaT set For default temperature difference set value, T 2，up The upper limit value of the water supply temperature of the cooling water is set, and the water supply temperature does not exceed the high-temperature alarm temperature;
the calculation formula of the optimized temperature difference set value is as follows:
if T 2 ＞T 2，up Then
Figure FDA0004082820090000032
If T 2 ≤T 2,up And T is 1 +ΔT set ＞T 2,up Then
Figure FDA0004082820090000033
If T 2 ≤T 2,up And T is 1 +ΔT set ≤T 2，up Then
Figure FDA0004082820090000034
6. The central air conditioner cooling water supply and return water temperature difference optimal control system according to claim 4, wherein: the range of the optimized temperature difference set value is between an upper temperature difference limit value and a lower temperature difference limit value, when the optimized temperature difference set value calculated by the controller (7) is larger than the upper temperature difference limit value, the optimized temperature difference set value is determined to be equal to the upper temperature difference limit value, and when the optimized temperature difference set value calculated by the controller (7) is smaller than the lower temperature difference limit value, the optimized temperature difference set value is determined to be equal to the lower temperature difference limit value.
7. A computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions for causing a processor to execute the central air-conditioning cooling water supply-return water temperature difference optimization control method according to any one of claims 4 to 6.
8. The utility model provides a central air conditioning cooling water supplies return water difference in temperature optimizing control equipment which characterized in that, central air conditioning cooling water supplies return water difference in temperature optimizing control equipment includes:
at least one processor and a storage medium, the memory communicatively coupled to the processor;
wherein the storage medium has stored thereon a computer program executable by the at least one processor, the computer program being executable by the at least one processor to enable the at least one processor to perform the central air conditioning cooling water supply-return water temperature difference optimizing control method of any one of claims 4 to 6.
CN202310128037.1A 2023-02-13 2023-02-13 Central air conditioner cooling water supply and return water temperature difference optimal control system and method Pending CN116294102A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116624969A (en) * 2023-07-21 2023-08-22 蘑菇物联技术（深圳）有限公司 Method, apparatus and medium for determining a temperature difference of cooling water supply and return water
CN117091241A (en) * 2023-08-21 2023-11-21 中瑞恒（北京）科技有限公司 Cold-warm water temperature difference control optimizing energy-saving method
CN117346305A (en) * 2023-12-06 2024-01-05 广东蘑菇物联科技有限公司 Temperature difference control method and device for cryopump, storage medium and computer equipment

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116624969A (en) * 2023-07-21 2023-08-22 蘑菇物联技术（深圳）有限公司 Method, apparatus and medium for determining a temperature difference of cooling water supply and return water
CN116624969B (en) * 2023-07-21 2023-10-10 蘑菇物联技术（深圳）有限公司 Method, apparatus and medium for determining a temperature difference of cooling water supply and return water
CN117091241A (en) * 2023-08-21 2023-11-21 中瑞恒（北京）科技有限公司 Cold-warm water temperature difference control optimizing energy-saving method
CN117091241B (en) * 2023-08-21 2024-04-16 中瑞恒（北京）科技有限公司 Cold-warm water temperature difference control optimizing energy-saving method
CN117346305A (en) * 2023-12-06 2024-01-05 广东蘑菇物联科技有限公司 Temperature difference control method and device for cryopump, storage medium and computer equipment
CN117346305B (en) * 2023-12-06 2024-03-08 广东蘑菇物联科技有限公司 Temperature difference control method and device for cryopump, storage medium and computer equipment

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