CN114440410B - Variable flow control method for freezing and cooling water pump based on heat exchange efficiency - Google Patents
Variable flow control method for freezing and cooling water pump based on heat exchange efficiency Download PDFInfo
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- CN114440410B CN114440410B CN202210131635.XA CN202210131635A CN114440410B CN 114440410 B CN114440410 B CN 114440410B CN 202210131635 A CN202210131635 A CN 202210131635A CN 114440410 B CN114440410 B CN 114440410B
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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
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/54—Control or safety arrangements characterised by user interfaces or communication using one central controller connected to several sub-controllers
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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
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/52—Indication arrangements, e.g. displays
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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
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/61—Control or safety arrangements characterised by user interfaces or communication using timers
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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
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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
- F24F11/70—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
- F24F11/84—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 valves
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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
- F24F11/70—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
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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
- F24F11/70—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
- F24F11/87—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling absorption or discharge of heat in outdoor units
- F24F11/871—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling absorption or discharge of heat in outdoor units by controlling outdoor fans
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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
- F24F2110/00—Control inputs relating to air properties
- F24F2110/10—Temperature
- F24F2110/12—Temperature of the outside air
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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
- F24F2110/00—Control inputs relating to air properties
- F24F2110/20—Humidity
- F24F2110/22—Humidity of the outside air
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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
- F24F2140/00—Control inputs relating to system states
- F24F2140/10—Pressure
- F24F2140/12—Heat-exchange fluid pressure
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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
- F24F2140/00—Control inputs relating to system states
- F24F2140/20—Heat-exchange fluid temperature
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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
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- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Fuzzy Systems (AREA)
- Mathematical Physics (AREA)
- Thermal Sciences (AREA)
- Air Conditioning Control Device (AREA)
- Other Air-Conditioning Systems (AREA)
Abstract
The invention discloses a variable flow control method for a freezing and cooling water pump based on heat exchange efficiency, which is characterized in that the data are processed by a PID algorithm through the performance parameter data of a freezing water system and a cooling water system running under different working conditions, and related parameters and energy consumption models are established; calculating energy consumption values of different operation parameters selected under different environments and system loads through the models; then, the system operation parameters which enable the energy consumption of the cooling water system to be the lowest when the system requirements are met under the specified environment and system load conditions are found; finally, the cooling water system is controlled according to the operation parameter so as to minimize the energy consumption. According to the invention, the influence of environmental factors and system cooling load on the energy consumption of the cooling water system is comprehensively considered, the fan frequency of the cooling tower and the operation frequency of the cooling pump are coordinately controlled, and the comprehensive energy consumption of the cooling water system is minimized on the premise of ensuring the efficient operation of the water chilling unit.
Description
Technical Field
The invention belongs to the technical field of energy and energy conservation, and particularly relates to a method for controlling variable flow rate of a freezing and cooling water pump based on heat exchange efficiency.
Background
In modern intelligent buildings, a central air-conditioning system is an indispensable component, but central air-conditioning is also a large energy-consuming user of modern buildings, and is also in a continuously increasing trend. Under such a large environment, how to make the central air conditioning system more energy-saving and more efficient, how to reasonably improve the comprehensive energy efficiency ratio of the central air conditioning system, and the central air conditioning system is more and more important for the current users.
The cooling water/chilled water system is an important component of the central air conditioning system, the energy consumption of the cooling water/chilled water system accounts for 15% -20% of the energy consumption of the central air conditioning system, and the energy-saving control of the cooling water/chilled water system has very important significance for overall energy saving. With the development of the water chilling unit technology, the flow of the current cooling water system can be changed within the range of 30% -130%, and when the load of the air conditioner and the outdoor environment are changed, the operation parameters of the cooling pump and the cooling tower are regulated to become the main mode of energy-saving control of the cooling water system, and the most commonly used control methods in the current engineering comprise constant temperature differential flow control, constant cooling water return water temperature control, constant flow control and the like. However, the above control method does not comprehensively consider the influence of the comprehensive energy efficiency, the system load and the environmental factors of the cooling water/chilled water system on the energy consumption of the cooling water/chilled water system.
Disclosure of Invention
The invention aims to control the minimum energy consumption of a chilled water system and a cooling water system under the conditions of different outdoor dry bulb temperatures, humidity and system cold load and on the premise of ensuring that the temperature of a condenser is the system demand temperature.
The technical scheme adopted by the invention is as follows:
the embodiment of the invention provides a variable flow control method for a refrigerating and cooling water pump based on heat exchange efficiency, which is applied to control of a central air conditioning system, wherein the operation of the central air conditioning system relates to cooling water circulation, refrigerating water circulation and air circulation of a fresh air system; the method is characterized by comprising the following steps of:
s1, according to the heat exchange performance of a refrigerating unit, regulating the temperature difference between water supply and return of chilled water to obtain a preset temperature difference value of the water supply and return;
s2, controlling the chilled water pump according to the temperature difference value of the water supply and return, wherein the control comprises the control of start-stop frequency and the adjustment of the flow rate of the chilled water;
s3, controlling the cooling water pump according to the temperature difference value of the water supply and return, and synchronously referencing the influence of the temperature and the humidity of the outdoor environment;
s4, judging whether the temperature of the cooling backwater is close to the current wet bulb temperature and the deviation value, performing variable frequency control on the cooling tower fan, controlling the rotating speed of the cooling tower fan, and increasing or decreasing the online quantity of the cooling tower in operation;
wherein step S1 further comprises:
s1.1, judging the heat exchange performance of a refrigerating unit, wherein the judging comprises gradually reducing a preset temperature difference value of the water supply and return in preset unit time, wherein the reduction temperature in the unit time is 0.1 ℃, and the running efficiency (COP) of the system is calculated in real time through the total energy consumption of the refrigerating unit, a water pump part and an air treatment unit and the refrigerating capacity, so that the highest running efficiency (COP) of the system is compared, and the preset temperature difference value of the water supply and return is obtained as the highest heat exchange capacity point of the heat exchanger;
wherein step S2 further comprises:
s2.1, calculating a control frequency of the chilled water pump through a PID algorithm, and synchronously comprehensively controlling the water supply and return water main pipe pressure difference value, the cold and hot quantity demand detected by a cold and hot quantity meter in real time and the chilled water supply temperature by referring to the number of the chilled water pumps which are increased or decreased to run, wherein the pressure difference value is equal to or higher than a set value of the water pressure difference;
wherein step S3 further comprises:
s3.1, switching and controlling the start and stop of the cooling water pump manually or automatically according to the requirement, and remotely accessing the centralized monitoring system;
s3.2, calculating control frequency of the cooling water pumps by using a PID algorithm according to the temperature difference value of the water supply and return, and increasing or reducing the number of the cooling water pumps in operation by the control frequency, wherein when a plurality of cooling water pumps of the same type operate simultaneously, pump lifts of the cooling water pumps are kept consistent;
wherein step S4 further comprises:
s4.1, performing variable frequency control, and reducing the rotating speed of a fan of the cooling tower when the value of the cooling backwater temperature minus the current wet bulb temperature is less than 2 ℃; when the temperature of cooling backwater minus the temperature of wet bulb is more than 2 ℃, increasing the rotating speed of a fan of the cooling tower;
s4.2, controlling the rotating speed of the cooling tower fan by switching manually or automatically according to the requirement, and remotely accessing the cooling tower fan into a centralized monitoring system.
Further, the running number of the chilled water pump and the cooling water pump is larger than that of the refrigerating unit.
Further, the unit time is based on 5 minutes.
Further, the temperature difference range of the temperature difference value of the water supply and return is 4-8 ℃.
The invention comprehensively considers the influence of environmental factors and system cooling load on the energy consumption of the cooling water system and the chilled water system, coordinates and controls the frequency of the cooling tower fan, the running frequency of the chilled pump and the running frequency of the cooling pump, and ensures that the comprehensive energy consumption of the chilled water and the chilled water system is the lowest on the premise of ensuring the efficient running of the chiller.
The invention will be further described with reference to the drawings and examples.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain the invention.
Fig. 1 is a chilled water cycle control flow chart of the present invention.
Fig. 2 is a flow chart of the cooling water circulation control of the present invention.
Detailed Description
The present invention will be further described with reference to specific embodiments and drawings, in which more details are set forth in the following description in order to provide a thorough understanding of the present invention, it will be apparent that the present invention can be embodied in many other forms than described herein, and that those skilled in the art may make similar generalizations and deductions depending on the actual application without departing from the spirit of the present invention, and therefore should not be taken as limiting the scope of the present invention in terms of the content of this specific embodiment.
According to the method, through the performance parameter data of the chilled water system and the cooling water system running under different working conditions, a PID algorithm is applied to process the data, and related parameters and energy consumption models are established; calculating energy consumption values of different operation parameters selected under different environments and system loads through the models; then, the system operation parameters which enable the energy consumption of the cooling water system to be the lowest when the system requirements are met under the specified environment and system load conditions are found; finally, the cooling water system is controlled according to the operation parameter so as to minimize the energy consumption.
Referring to fig. 1 and 2, the method for controlling variable flow rate of the freezing and cooling water pump based on heat exchange efficiency is applied to control of a central air conditioning system, and relates to cooling water circulation, freezing water circulation and air circulation of a fresh air system in operation of the central air conditioning system, wherein the cooling water circulation cools heat in a refrigerating unit through cooling water in a cooling tower, the freezing water circulation cools cold energy generated in the refrigerating unit through the freezing water in an air treatment unit, the freezing water circulation exchanges heat with the air circulation through the air treatment unit, a variable speed cooling water pump is arranged on the cooling water circulation, and a variable speed freezing water pump is arranged on the freezing water circulation; the method is characterized by comprising the following steps of:
s1, according to the heat exchange performance of a refrigerating unit, regulating the temperature difference between water supply and return of chilled water to obtain a preset temperature difference value of the water supply and return;
s2, controlling the chilled water pump according to the temperature difference value of the water supply and return, wherein the control comprises the control of start-stop frequency and the adjustment of the flow rate of the chilled water;
s3, controlling the cooling water pump according to the temperature difference value of the water supply and return, and synchronously referencing the influence of the temperature and the humidity of the outdoor environment;
s4, judging whether the temperature of the cooling backwater is close to the current wet bulb temperature and the deviation value, performing variable frequency control on the cooling tower fan, controlling the rotating speed of the cooling tower fan, and increasing or decreasing the online quantity of the cooling tower in operation;
wherein step S1 further comprises:
s1.1, judging the heat exchange performance of a refrigerating unit, wherein the judging comprises gradually reducing a preset temperature difference value of the water supply and return in preset unit time, wherein the reduction temperature in the unit time is 0.1 ℃, and the running efficiency (COP) of the system is calculated in real time through the total energy consumption of the refrigerating unit, a water pump part and an air treatment unit and the refrigerating capacity, so that the highest running efficiency (COP) of the system is compared, and the preset temperature difference value of the water supply and return is obtained as the highest heat exchange capacity point of the heat exchanger;
wherein step S2 further comprises:
s2.1, calculating a control frequency of the chilled water pump through a PID algorithm, and synchronously comprehensively controlling the water supply and return water main pipe pressure difference value, the cold and hot quantity demand detected by a cold and hot quantity meter in real time and the chilled water supply temperature by referring to the number of the chilled water pumps which are increased or decreased to run, wherein the pressure difference value is equal to or higher than a set value of the water pressure difference;
wherein step S3 further comprises:
s3.1, switching and controlling the start and stop of the cooling water pump manually or automatically according to the requirement, and remotely accessing the centralized monitoring system;
s3.2, calculating control frequency of the cooling water pumps by using a PID algorithm according to the temperature difference value of the water supply and return, and increasing or reducing the number of the cooling water pumps in operation by the control frequency, wherein when a plurality of cooling water pumps of the same type operate simultaneously, pump lifts of the cooling water pumps are kept consistent;
wherein step S4 further comprises:
s4.1, performing variable frequency control, and reducing the rotating speed of a fan of the cooling tower when the value of the cooling backwater temperature minus the current wet bulb temperature is less than 2 ℃; when the temperature of cooling backwater minus the temperature of wet bulb is more than 2 ℃, increasing the rotating speed of a fan of the cooling tower;
s4.2, controlling the rotating speed of the cooling tower fan by switching manually or automatically according to the requirement, and remotely accessing the cooling tower fan into a centralized monitoring system.
Further, the running number of the chilled water pump and the cooling water pump is larger than that of the refrigerating unit.
Further, the unit time is based on 5 minutes.
Further, the temperature difference range of the temperature difference value of the water supply and return is 4-8 ℃.
Further, by applying the method of the invention, the refrigerating unit, the cooling tower, the air treatment unit, the variable-speed cooling water pump and the variable-speed chilled water pump related to the cooling water circulation, the chilled water circulation and the air circulation of the fresh air system comprise the following components:
(1) Communication interface (heat pump unit): transmitting data to a gateway by using Modbus interfaces and the like, and finally monitoring equipment parameters on an upper computer interface;
(2) A water flow switch: the heat pump unit is provided with a main machine without cold and hot water flow and does not operate;
(3) Liquid level switch: the water supplementing device is used, and the liquid level is one each;
(4) A water pipe pressure sensor: the cold and hot water supply and return pipes are all measured;
(5) Water pipe temperature sensor: the cold and hot water supply and return pipes are all measured;
(6) Outdoor temperature and humidity sensor: measuring outdoor temperature and humidity, and calculating dew point temperature and wet bulb temperature;
(7) And (3) switching the valve: the water cooling and heating pipeline is arranged and is controlled in linkage with the heat pump unit;
(8) A bypass valve: independent differential pressure control, no need to be demonstrated on the system;
(9) Cold and heat flow meter: measuring the flow of the total cold water pipe and the flow of the total hot water pipe, and calculating the cooling quantity and the heating quantity;
(10) Heat pump set switch board: the multifunctional remote transmission electric energy meter is needed to be arranged, and the power consumption of the unit is measured;
(11) Cold and hot water pump frequency conversion cabinet: exchanging signals with a controller, and controlling the output frequency of the frequency converter through temperature difference and pressure difference; the device is provided with a manual frequency modulation knob; the variable frequency cabinet is provided with a multifunctional remote electric energy meter.
Further, by applying the method of the present invention, the monitoring content used includes:
and (3) equipment monitoring: on-site/remote start-stop control and state display (operation, fault and manual operation) of the heat pump unit, the cold water pump and the hot water pump; other parameters such as the load rate of the heat pump unit, the water inlet and outlet temperature, the condensation approaching temperature and the like;
system functions: a timing power-on function, a one-key start-off function, an accumulated running time display, and a priority to start high-efficiency equipment or equipment with the lowest running time;
and (3) energy consumption monitoring: monitoring energy consumption, voltage, current, power factor and the like of a host machine, a water pump and the like;
and (3) energy monitoring: monitoring the total cooling capacity, the total heat capacity and other parameters of the cold and heat meter;
and (3) temperature and humidity monitoring: cooling and heating total water inlet and outlet temperature, outdoor temperature and humidity, dew point temperature and wet bulb temperature; setting temperature compensation on an upper computer; when the acquired value of the sensor is not in the conventional range, the sensor fault is processed;
total water inlet and outlet temperature redundancy for cooling and heating: the total water inlet and outlet temperature value of cooling and heating is compared with the average temperature value of the running host computer, when the difference is more than 2 ℃ (settable), the sensor fault alarm is carried out, and the running host computer average temperature is used for replacing the sensor main pipe temperature to control the system (the upper computer is provided with a sensor temperature/host computer temperature manual switching button);
pressure monitoring: total water inlet and outlet pressure for cooling and heating; when the acquired value of the sensor is not in the conventional range, the sensor fault is processed;
water level: high and low liquid level display (generally not monitored);
and (3) switching the valve: an in-situ/remote, switch control and in-place signal display is needed (fault is displayed if the switch is not in place for more than 1 minute after the switch is turned on); when the valve is closed, the red light flashes, and the closed red light is always on; when the valve is opened, the green light flashes, and the green light is normally on when the valve is opened in place;
and (3) regulating valve: a mechanical manual adjusting device and an opening signal feedback display are needed;
variable frequency control of the cold and hot water pump: automatically converting the frequency according to the temperature difference and the pressure difference and feeding back a frequency value; the device has the function of manually setting the frequency of an upper computer; when a plurality of pumps of the same type are operated, the frequencies are consistent, so that the pump lifts are kept consistent;
redundancy: the air conditioning units are mutually standby; the cold water pump and the hot water pump are mutually standby;
start-stop sequence: when the system program starts and stops and the interlocking unit starts, the electric butterfly valves at the cold water pipe and the hot water pipe are opened, and the cold water pump and the hot water pump are started in sequence. And after the water flow is confirmed by the water flow switch, starting the air-cooled heat pump unit. When the machine is stopped, the air-cooled heat pump unit is stopped first, and after a certain delay time, the water pump is stopped and the valve is closed. Any set of refrigeration system stops running, and all units, water pumps and electric butterfly valves corresponding to the system are closed in an interlocking way;
and (3) linkage of a host: host joint control is carried out according to the load rate energy efficiency curve, so that the host joint control operates in a high energy efficiency interval; when a plurality of hosts are started, when the load rate or the flow rate of each running host has obvious difference, an alarm is given to remind a manager to check the problems of the hosts, and at the moment, the linkage control of the hosts is not easy to start; the water outlet temperature of the host can be manually set on the upper computer;
forming a real-time curve, a history curve and a report form: heat quantity value, cold quantity value, ratio of heat quantity value to cold quantity value, load rate of heat pump unit, cold and hot water inlet and outlet temperature of heat pump, condensation approaching temperature, energy consumption of main machine and water pump, total cooling quantity, total heat supply quantity, total water inlet and outlet temperature of cooling and heating, outdoor temperature and humidity, dew point temperature, wet bulb temperature, total water inlet and outlet pressure of cooling and heating and COP curve.
In the invention, when the system is started, the cooling water system is operated in a full-power mode (namely, the cooling tower fan, the cooling pump and the freezing pump are operated according to design parameters) for a period of time, and the system enters an optimal control mode after being started stably.
The invention is not related in part to the same as or can be practiced with the prior art.
Although embodiments of the present invention have been disclosed above, it is not limited to the applications listed in the specification and the embodiments, which are to be fully applicable to the various fields of adaptation of the present invention, and further modifications may be readily effected by those skilled in the art, so that the present invention is not limited to the specific details and illustrations shown and described herein without departing from the general concepts defined by the claims and the scope of equivalents.
Claims (4)
1. The method is applied to control of a central air conditioning system, and relates to cooling water circulation, chilled water circulation and air circulation of a fresh air system in the operation of the central air conditioning system, wherein the cooling water circulation cools heat in a refrigerating unit through cooling water in a cooling tower, the chilled water circulation cools cold generated in the refrigerating unit through the chilled water in an air treatment unit, the chilled water circulation exchanges heat with the air circulation through the air treatment unit, a variable speed cooling water pump is arranged on the cooling water circulation, and a variable speed chilled water pump is arranged on the chilled water circulation; the method is characterized by comprising the following steps of:
s1, according to the heat exchange performance of a refrigerating unit, regulating the temperature difference between water supply and return of chilled water to obtain a preset temperature difference value of the water supply and return;
s2, controlling the chilled water pump according to the temperature difference value of the water supply and return, wherein the control comprises the control of start-stop frequency and the adjustment of the flow rate of the chilled water;
s3, controlling the cooling water pump according to the temperature difference value of the water supply and return, and synchronously referencing the influence of the temperature and the humidity of the outdoor environment;
s4, judging whether the temperature of the cooling backwater is close to the current wet bulb temperature and the deviation value, performing variable frequency control on the cooling tower fan, controlling the rotating speed of the cooling tower fan, and increasing or decreasing the online quantity of the cooling tower in operation;
wherein step S1 further comprises:
s1.1, judging the heat exchange performance of a refrigerating unit, wherein the judging comprises gradually reducing a preset temperature difference value of the water supply and return in preset unit time, wherein the reduction temperature in the unit time is 0.1 ℃, and the running efficiency (COP) of the system is calculated in real time through the total energy consumption of the refrigerating unit, a water pump part and an air treatment unit and the refrigerating capacity, so that the highest running efficiency (COP) of the system is compared, and the preset temperature difference value of the water supply and return is obtained as the highest heat exchange capacity point of the heat exchanger;
wherein step S2 further comprises:
s2.1, calculating a control frequency of the chilled water pump through a PID algorithm, and synchronously comprehensively controlling the water supply and return water main pipe pressure difference value, the cold and hot quantity demand detected by a cold and hot quantity meter in real time and the chilled water supply temperature by referring to the number of the chilled water pumps which are increased or decreased to run, wherein the pressure difference value is equal to or higher than a set value of the water pressure difference;
wherein step S3 further comprises:
s3.1, switching and controlling the start and stop of the cooling water pump manually or automatically according to the requirement, and remotely accessing the centralized monitoring system;
s3.2, calculating control frequency of the cooling water pumps by using a PID algorithm according to the temperature difference value of the water supply and return, and increasing or reducing the number of the cooling water pumps in operation by the control frequency, wherein when a plurality of cooling water pumps of the same type operate simultaneously, pump lifts of the cooling water pumps are kept consistent;
wherein step S4 further comprises:
s4.1, performing variable frequency control, and reducing the rotating speed of a fan of the cooling tower when the value of the cooling backwater temperature minus the current wet bulb temperature is less than 2 ℃; when the temperature of cooling backwater minus the temperature of wet bulb is more than 2 ℃, increasing the rotating speed of a fan of the cooling tower;
s4.2, controlling the rotating speed of the cooling tower fan by switching manually or automatically according to the requirement, and remotely accessing the cooling tower fan into a centralized monitoring system.
2. The method for variable flow control of chilled and chilled water pumps based on heat transfer efficiency of claim 1, wherein the number of chilled water pumps and chilled water pumps is greater than the number of chiller units.
3. The method for variable flow control of a chilled or cooled water pump based on heat exchange efficiency of claim 1, wherein the unit time is based on 5 minutes.
4. The method for variable flow control of a chilled or cooled water pump based on heat exchange efficiency of claim 1, wherein the temperature difference range of the temperature difference value of the water supply and return is 4-8 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210131635.XA CN114440410B (en) | 2022-02-14 | 2022-02-14 | Variable flow control method for freezing and cooling water pump based on heat exchange efficiency |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210131635.XA CN114440410B (en) | 2022-02-14 | 2022-02-14 | Variable flow control method for freezing and cooling water pump based on heat exchange efficiency |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114440410A CN114440410A (en) | 2022-05-06 |
| CN114440410B true CN114440410B (en) | 2023-09-08 |
Family
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| CN115164375B (en) * | 2022-07-08 | 2024-04-26 | 南京优助智能科技有限公司 | Flow estimation method and system for central air conditioner cold and heat source system |
| CN115235051B (en) * | 2022-07-27 | 2023-03-14 | 广州市铭汉科技股份有限公司 | Double-control cooling water control system |
| CN115860445B (en) * | 2022-11-15 | 2024-02-09 | 中核陕西铀浓缩有限公司 | Multi-level collaborative scheduling method for uranium enrichment refrigerating unit and closed cooling tower |
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| CN201059715Y (en) * | 2007-07-06 | 2008-05-14 | 北京时代嘉华环境控制科技有限公司 | Central air-conditioning freezing stations quality regulating control system |
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