CN111442438A - System and control method for refrigerating machine room - Google Patents
System and control method for refrigerating machine room Download PDFInfo
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- CN111442438A CN111442438A CN202010182582.5A CN202010182582A CN111442438A CN 111442438 A CN111442438 A CN 111442438A CN 202010182582 A CN202010182582 A CN 202010182582A CN 111442438 A CN111442438 A CN 111442438A
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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
- F24F5/00—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater
- F24F5/0003—Exclusively-fluid systems
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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
- F24F11/72—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure
- F24F11/74—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity
- F24F11/77—Control systems characterised by their outputs; Constructional details thereof for controlling the supply of treated air, e.g. its pressure for controlling air flow rate or air velocity by controlling the speed of ventilators
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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
- F24F11/89—Arrangement or mounting of control or safety devices
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
Abstract
The invention discloses a system of a refrigerating machine room, which comprises at least two cold water main machines, a cooling tower, at least two refrigerating water pumps, at least two cooling water pumps and a detection and control device, wherein the at least two cooling water main machines are connected with the cooling tower through a pipeline; the parallel freezing water pumps are connected with the parallel cold water main machine and then connected with the parallel cooling water pumps, and the parallel cooling water pumps are connected with the cooling tower; the detection and control device is used for obtaining the corresponding cooling water reduced temperature or the adjustment value of the host load according to the matching relation between the cooling water temperature and the host load of the cold water; the system is also used for controlling the number and the frequency of the fans of the cooling tower according to the preset relations between the outlet water temperature of the cooling tower and the number and the frequency of the fans of the cooling tower; the cooling water pump is also used for controlling the frequency and the flow of the cooling water pump according to the preset relationship between the temperature difference of the supplied and returned water and the frequency and the flow of the cooling water pump; and the system is also used for controlling the frequency and the flow of the chilled water pump according to the preset relation between the pressure difference at the tail end of the system and the frequency and the flow of the chilled water pump.
Description
Technical Field
The invention relates to a refrigerating machine room for a factory, in particular to a system of the refrigerating machine room and a control method.
Background
Based on the construction of a conventional refrigerating machine room, the working of each working stage in a project establishment stage, a project design stage, a project implementation stage, a project debugging stage and a project operation maintenance stage is disjointed and the quality of personnel is different, so that the operating efficiency of the refrigerating machine room is poor, the energy consumption cost is high, and no person bears responsibility for the operating effect of the refrigerating machine room; on the other hand, the refrigerating machine rooms are designed according to the maximum load selection of the system during design, the running time of the refrigerating machine room system during full load is almost 10% and the system often runs in a 40% -70% load section, and the energy efficiency of the system is lower and the energy consumption cost is higher than that of the system during full load.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a system and a control method of a refrigerating machine room, which are used for solving the problems of high energy consumption, low energy efficiency and high operation cost.
The purpose of the invention is realized by adopting the following technical scheme:
a system of a refrigerating machine room comprises at least two cold water main machines, a cooling tower, at least two refrigerating water pumps, at least two cooling water pumps and a detection and control device; at least two freezing water pumps are connected in parallel, at least two cold water hosts are connected in parallel, at least two cooling water pumps are connected in parallel, the freezing water pumps which are connected in parallel are connected with the cold water hosts which are connected in parallel and then connected with the cooling water pumps which are connected in parallel, and the cooling water pumps which are connected in parallel are connected with a cooling tower;
the detection and control device is used for detecting the temperature of cooling water, obtaining the load of the cold water host and obtaining the corresponding reduced temperature of the cooling water or the adjustment value of the load of the host according to the matching relation between the temperature of the cooling water and the load of the cold water host;
the detection and control device is also used for acquiring the water outlet temperature of the cooling tower and controlling the number and the frequency of fans of the cooling tower according to the preset relationship between the water outlet temperature of the cooling tower and the number and the frequency of the fans of the cooling tower;
the detection and control device is also used for acquiring a water supply and return temperature difference and controlling the frequency and the flow of the cooling water pump according to a preset relation between the water supply and return temperature difference and the frequency and the flow of the cooling water pump;
the detection and control device is also used for acquiring the pressure difference at the tail end of the system and controlling the frequency and the flow of the chilled water pump according to the preset relation between the pressure difference at the tail end of the system and the frequency and the flow of the chilled water pump.
Further, the detection and control device comprises a cooling water temperature sensor and a load monitoring device, wherein the cooling water temperature sensor is used for detecting the temperature of cooling water, and the load monitoring device is used for obtaining the load of the cold water host machine, and the temperature of the cooling water is the temperature of the cooling water after the cooling water is cooled by the cold water host machine.
Furthermore, the detection and control device also comprises an outlet water temperature sensor, and the outlet water temperature sensor is used for acquiring the outlet water temperature of the cooling tower;
the detection and control device further comprises a water supply temperature sensor and a water return temperature sensor, the water supply temperature sensor is used for obtaining water supply temperature, the water return temperature sensor is used for obtaining water return temperature, and the water supply temperature and the water return temperature are used for obtaining the water supply and return temperature difference.
Further, the detection and control device further comprises a time detector and a flow meter, wherein the time detector is used for detecting the operation time of the chilled water pump or the cooling water pump, and the flow meter is used for detecting the flow of the chilled water pump or the cooling water pump;
the detection and control device is also used for increasing the number of the chilled water pumps or the cooling water pumps when the time detector detects that the running time of the chilled water pumps or the cooling water pumps reaches a target time value and the flow of the chilled water pumps or the cooling water pumps does not reach a target flow value.
Further, the system of the refrigerating machine room further comprises a PID controller, and the PID controller performs PID control on the running refrigerating water pump or cooling water pump according to the water supply and return temperature difference.
Correspondingly, the invention also provides a control method of the refrigerating machine room, which comprises the steps of detecting the temperature of cooling water, obtaining the load of the cold water main machine, and obtaining the corresponding reduced temperature of the cooling water or the adjustment value of the load of the main machine according to the matching relation between the temperature of the cooling water and the load of the cold water main machine; the number of the cold water main machines is at least two, and the at least two cold water main machines are connected in parallel;
acquiring the outlet water temperature of the cooling tower, and controlling the number and frequency of fans of the cooling tower according to the preset relationship between the outlet water temperature of the cooling tower and the number and frequency of the fans of the cooling tower;
acquiring a temperature difference between supply water and return water, and controlling the frequency and the flow of the cooling water pump according to a preset relation between the temperature difference between the supply water and the return water and the frequency and the flow of the cooling water pump; the number of the cooling water pumps is at least two, and the at least two cooling water pumps are connected in parallel;
acquiring a system tail end pressure difference, and controlling the frequency and the flow of the chilled water pump according to a preset relation between the system tail end pressure difference and the frequency and the flow of the chilled water pump; the number of the freezing water pumps is at least two, the at least two freezing water pumps are connected in parallel, the freezing water pumps connected in parallel are connected with the cold water main machine connected in parallel and then connected with the cooling water pumps connected in parallel, and the cooling water pumps connected in parallel are connected with the cooling tower.
Further, the cooling water temperature is the temperature of the water cooled by the cold water main machine.
And further, obtaining a water supply temperature and a water return temperature, and obtaining the water supply and return temperature difference through the water supply temperature and the water return temperature.
Further, detecting the running time of the chilled water pump or the cooling water pump, and simultaneously detecting the flow of the chilled water pump or the cooling water pump;
and when the time detector detects that the running time of the chilled water pumps or the cooling water pumps reaches a target time value and the flow of the chilled water pumps or the cooling water pumps does not reach a target flow value, increasing the number of the chilled water pumps or the cooling water pumps.
And further, performing PID control on the running freezing water pump or cooling water pump according to the temperature difference between the supplied water and the returned water.
Compared with the prior art, the invention has the beneficial effects that:
(1) the connection of the freezing water pump, the cooling water pump and the cold water main machine adopts the parallel male pipe, so that a water separator and a water collector are omitted, and the power of the freezing water pump and the cooling water pump is lowest; and the equipment can be accurately controlled according to the control method, so that the energy consumption is reduced.
(2) The invention provides an operation strategy of the cold water main machine, an operation control strategy of the chilled water pump, an operation control strategy of the cooling water pump and an operation control strategy of the cooling tower, so that the use efficiency of each part is optimized, the lowest energy consumption of the cold water main machine, the chilled water pump, the cooling water pump and the cooling tower is ensured, and the energy efficiency of the whole refrigerating machine room can be improved.
(3) The invention realizes the automatic control and management of the refrigerating machine room equipment through the optimized control logic, prolongs the service life of the refrigerating machine room equipment, ensures the operation safety of the refrigerating machine room equipment, and further reduces the energy consumption cost and the operation and maintenance cost.
Drawings
Fig. 1 is a schematic diagram of a system of a refrigeration machine room of the present invention;
fig. 2 is a simplified diagram of a system of a refrigeration machine room according to the present invention;
fig. 3 is a graph showing performance curves of different cooling water temperature conditions of a water chiller in a system of a refrigeration machine room according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Referring to fig. 1 to 3, a system of a refrigeration machine room includes at least two main cooling water machines, a cooling tower, at least two chilled water pumps, at least two cooling water pumps, and a detection and control device.
As shown in fig. 1, at least two chilled water pumps are connected in parallel, at least two cold water main machines are connected in parallel, at least two cooling water pumps are connected in parallel, the chilled water pumps connected in parallel are connected with the cold water main machines connected in parallel and then connected with the cooling water pumps connected in parallel, and the cooling water pumps connected in parallel are connected with a cooling tower. Preferably, the energy efficiency of the cold water main machine is in the first grade of the national standard, and the energy efficiency of the refrigerating water pump, the cooling water pump and the cooling tower equipment meets the second grade and above of the national standard.
The freezing water pump, the cooling water pump and the cold water main machine are connected by adopting the parallel male pipes, so that a water separator and a water collector are omitted, and the power of the freezing water pump and the cooling water pump is lowest; and the equipment can be accurately controlled according to the control method, so that the energy consumption is reduced. Local resistance components such as valves, elbows and the like adopt low-resistance design products; the reasonable resistance of the system pipeline is ensured, and the power of the chilled water pump and the cooling water pump is the lowest.
Preferably, the whole refrigerating machine room is guided and implemented by a BIM (building information modeling) model, so that the project implementation is ensured to meet the design requirement standard.
The detection and control device specifically comprises an upper computer monitoring system, a P L C control cabinet, a cooling water temperature sensor, a load monitoring device, an outlet water temperature sensor, a water supply temperature sensor, a return water temperature sensor, a pressure sensor, a time detector, a flowmeter, an intelligent electric meter, a PID controller and the like.
Referring to fig. 3, the performance curve of the water chilling unit under different cooling water temperature conditions and different loads of the water chilling main unit is that the lower the cooling water temperature is, the higher the performance of the main unit is; the higher the temperature of the cooling water is, the lower the performance of the main machine is; in addition, when the cooling water temperature is fixed, the main engine is in the high-energy efficiency interval when the load is 40% -90%.
Therefore, the invention improves the energy efficiency of the main engine by reducing the temperature of the cooling water and the consideration of the operation load of the main engine.
The system comprises a cooling water temperature sensor, a load monitoring device, a detection and control device, a host computer, a P L C control cabinet, a P L C control cabinet and a P L C control cabinet, wherein the cooling water temperature sensor is used for detecting the temperature of cooling water, the load monitoring device is used for obtaining the load of a cold water host, the temperature of the cooling water is the temperature of the cooling water after the cooling water is cooled by the cold water host, the detection and control device is used for detecting the temperature of the cooling water and obtaining the load of the cold water host, and the corresponding temperature reduction of the cooling water or the adjustment value of the load of the host are obtained according to the matching relation between the temperature of the cooling water and the load of the cold water host, the upper computer monitoring system is used for obtaining the corresponding temperature reduction of the cooling water or the adjustment value of the load of the host and sending the temperature reduction of the.
In addition, when the temperature of cooling water is fixed, the temperature of the outlet water of chilled water is locked to be 6 ℃ according to a cold water host, and the temperature is adapted to change according to the self capacity of the unit; when the flow meter detects that the current of a single cold water main machine reaches 95%, the water outlet temperature cannot be stabilized, starting another machine set, and delaying the machine adding for 5 min; and 2 or more cold water main machines are ensured to run, and the started main machines run in a high-efficiency area as far as possible.
The temperature of the cooling water is closely related to the heat dissipation capacity of the cooling tower, wherein the outlet water temperature of the cooling tower is the approach degree of the wet bulb temperature (the wet bulb temperature plus the approach degree is 2-4 ℃). Therefore, the area of the filler of the cooling tower can be fully utilized as much as possible, the flow of the cooling water is ensured to be under the variable flow working condition of 15-120%, the filler can be fully filmed, and the heat radiation performance of the cooling tower is free from fluctuation and low in attenuation.
The device comprises a water outlet temperature sensor, a detection and control device, a host computer monitoring system, a P L C control cabinet, a P L C control cabinet and a P L C control cabinet, wherein the water outlet temperature sensor is used for acquiring the water outlet temperature of the cooling tower, the detection and control device is also used for acquiring the water outlet temperature of the cooling tower, and controlling the number and the frequency of fans of the cooling tower according to the preset relation between the water outlet temperature of the cooling tower and the number and the frequency of the fans of the cooling tower, the upper computer monitoring system acquires the number and the frequency of the fans of the cooling tower according to the preset relation between the water outlet temperature of the cooling tower and the number and the frequency of the fans of the cooling tower and sends the number and the frequency.
In other embodiments, the outlet water temperature of the cooling tower can be obtained by obtaining the wet bulb temperature, i.e. the wet bulb temperature + the approximation degree of 2-4 ℃ is the outlet water temperature of the cooling tower.
The detection and control device is also used for acquiring the temperature difference between water supply and return water and controlling the frequency and the flow of the cooling water pump according to the preset relation between the temperature difference between water supply and return water and the frequency and the flow of the cooling water pump, wherein the upper computer monitoring system acquires the frequency and the flow of the cooling water pump according to the preset relation between the temperature difference between water supply and return water and the frequency and the flow of the cooling water pump and sends the frequency and the flow of the cooling water pump to the P L C control cabinet, the P L C control cabinet is connected with the cooling water pump, and the P L C control cabinet controls the frequency and the flow of the cooling water pump.
Specifically, the temperature difference between cooling/freezing water supply and return water is 5 ℃ as a target value, the temperature difference is higher than 5 ℃, the frequency of a water pump is increased, and the flow of the water pump is increased; the temperature difference is less than 5 ℃, the water pump frequency is reduced, and the water pump flow is reduced.
The refrigerating water pump has large flow, long pipeline and large inertia of the system, so the worst pressure difference set value at the tail end of the system is adopted as a target value, and when the pressure difference load at the tail end of the system changes, the tail end temperature control system can automatically adjust the electric regulating valve at the tail end conventionally to cause the change of the pressure difference at the tail end, so the frequency and the flow of the refrigerating water pump are controlled according to the pressure difference at the tail end of the system. Wherein the system end differential pressure is obtained by a pressure sensor.
The upper computer monitoring system obtains the frequency and the flow of the chilled water pump according to the preset relation between the pressure difference at the tail end of the system and the frequency and the flow of the chilled water pump, and sends the frequency and the flow of the chilled water pump to the P L C control cabinet, the P L C control cabinet is connected with the chilled water pump, and the P L C control cabinet controls the frequency and the flow of the chilled water pump.
Specifically, when the pressure difference at the tail end of the system is increased to a pressure difference target value, the frequency of the water pump is increased, and the flow of the water pump is increased; when the pressure difference at the tail end of the system is reduced to a pressure difference target value, the frequency of the water pump is reduced, and the flow of the water pump is reduced.
The upper computer monitoring system is used for judging whether the running time of the freezing water pump or the cooling water pump reaches the target time value and whether the flow of the freezing water pump or the cooling water pump reaches the target flow value or not by the time detector, generating a signal for increasing the number of the freezing water pumps or the cooling water pumps when the running time of the freezing water pump or the cooling water pump reaches the target time value and the flow of the freezing water pump or the cooling water pump reaches the target flow value by the time detector and sending the signal to the P L C control cabinet, and controlling the number of the freezing water pumps or the cooling water pumps to increase by the P L C control cabinet.
And the PID controller performs PID control on the running freezing water pump or cooling water pump according to the temperature difference of the supplied water and the returned water. The PID control is critical to measuring the actual value of the controlled variable, and using this deviation to correct the response of the system, as compared to the desired value, to perform the regulatory control. Specifically, after the frequency of a single running water pump is maintained in a full working condition and runs for a certain preset time, for example, 10min, the system considers that the running water pump cannot meet the requirement of the tail end on the flow, at this time, a program sends an instruction for increasing 1 water pump, the frequency is gradually increased from zero (increased to above the minimum frequency within 10 s), the frequency of the running water pump is gradually reduced along with the increase of the frequency of the water pump, when the same value is reached, the frequency of the running water pump is changed simultaneously, and the system performs uniform PID control on the frequency of the running water pump according to the temperature difference of the supplied water and the returned water.
The connection of the freezing water pump, the cooling water pump and the cold water main machine adopts the parallel male pipe, so that a water separator and a water collector are omitted, and the power of the freezing water pump and the cooling water pump is lowest; the equipment can be accurately controlled according to the control method, so that the energy consumption is reduced; the invention provides an operation strategy of the cold water main machine, an operation control strategy of the chilled water pump, an operation control strategy of the cooling water pump and an operation control strategy of the cooling tower, so that the use efficiency of each part is optimized, the lowest energy consumption of the cold water main machine, the chilled water pump, the cooling water pump and the cooling tower is ensured, and the energy efficiency of the whole refrigerating machine room can be improved; the invention realizes the automatic control and management of the refrigerating machine room equipment through the optimized control logic, prolongs the service life of the refrigerating machine room equipment, ensures the operation safety of the refrigerating machine room equipment, and further reduces the energy consumption cost and the operation and maintenance cost.
Correspondingly, the invention also provides a control method of the refrigerating machine room.
The method specifically comprises a control strategy of a cold water main machine, a control strategy of a cooling tower, a control strategy of a cooling water pump and a control strategy of a chilled water pump.
The system for executing the whole control method comprises at least two cold water hosts, a cooling tower, at least two chilled water pumps, at least two cooling water pumps and a detection and control device. The cooling tower comprises at least two refrigeration water pumps, at least two cooling water main machines, at least two cooling water pumps, at least two cooling towers and a cooling tower, wherein the at least two refrigeration water pumps are connected in parallel, the at least two cooling water main machines are connected in parallel, the at least two cooling water pumps are connected in parallel, the refrigeration water pumps which are connected in parallel are connected with the cooling water main machines which are connected in parallel and then connected with the cooling. Preferably, the energy efficiency of the cold water main machine is in the first grade of the national standard, and the energy efficiency of the refrigerating water pump, the cooling water pump and the cooling tower equipment meets the second grade and above of the national standard. The freezing water pump, the cooling water pump and the cold water main machine are connected by adopting the parallel male pipes, so that a water separator and a water collector are omitted, and the power of the freezing water pump and the cooling water pump is lowest; and the equipment can be accurately controlled according to the control method, so that the energy consumption is reduced. Local resistance components such as valves, elbows and the like adopt low-resistance design products; the reasonable resistance of the system pipeline is ensured, and the power of the chilled water pump and the cooling water pump is the lowest.
Preferably, the whole refrigerating machine room is guided and implemented by a BIM (building information modeling) model, so that the project implementation is ensured to meet the design requirement standard.
The detection and control device specifically comprises an upper computer monitoring system, a P L C control cabinet, a cooling water temperature sensor, a load monitoring device, an outlet water temperature sensor, a water supply temperature sensor, a return water temperature sensor, a pressure sensor, a time detector, a flowmeter, an intelligent electric meter, a PID controller and the like.
The control method of the cold water host comprises the steps of detecting the temperature of cooling water and obtaining the load of the cold water host, wherein the temperature of the cooling water is the temperature of the cooling water cooled by the cold water host, and obtaining the corresponding reduced temperature of the cooling water or the adjusted value of the load of the host according to the matching relation between the temperature of the cooling water and the load of the cold water host, wherein at least two cold water hosts are connected in parallel, the upper computer monitoring system is used for obtaining the corresponding reduced temperature of the cooling water or the adjusted value of the load of the host according to the matching relation between the temperature of the cooling water and the load of the cold water host, the upper computer monitoring system is used for sending the reduced temperature of the cooling water or the adjusted value of the load of the host to a P L C control cabinet, the P L C control cabinet is connected with the cold water host, and the P L.
In addition, when the temperature of cooling water is fixed, the temperature of the outlet water of chilled water is locked to be 6 ℃ according to a cold water host, and the temperature is adapted to change according to the self capacity of the unit; when the flow meter detects that the current of a single cold water main machine reaches 95%, the water outlet temperature cannot be stabilized, starting another machine set, and delaying the machine adding for 5 min; and 2 or more cold water main machines are ensured to run, and the started main machines run in a high-efficiency area as far as possible.
The temperature of the cooling water is closely related to the heat dissipation capacity of the cooling tower, wherein the outlet water temperature of the cooling tower is the approach degree of the wet bulb temperature (the wet bulb temperature plus the approach degree is 2-4 ℃). Therefore, the area of the filler of the cooling tower can be fully utilized as much as possible, the flow of the cooling water is ensured to be under the variable flow working condition of 15-120%, the filler can be fully filmed, and the heat radiation performance of the cooling tower is free from fluctuation and low in attenuation.
Therefore, the control strategy of the cooling tower comprises the steps of obtaining the water outlet temperature of the cooling tower, controlling the number and the frequency of fans of the cooling tower according to the preset relation between the water outlet temperature of the cooling tower and the number and the frequency of the fans of the cooling tower, wherein the number and the frequency of the fans of the cooling tower are obtained by the upper computer monitoring system according to the preset relation between the water outlet temperature of the cooling tower and the number and the frequency of the fans of the cooling tower and are sent to a P L C control cabinet, the P L C control cabinet is connected with the cooling tower, and the number and the frequency of the fans of the cooling tower are controlled by the P L C control cabinet.
In other embodiments, the outlet water temperature of the cooling tower can be obtained by obtaining the wet bulb temperature, i.e. the wet bulb temperature + the approximation degree of 2-4 ℃ is the outlet water temperature of the cooling tower.
The control strategy of the cooling water pump is based on the premise that the lowest allowable flow of the host is met, preferably, the water supply temperature sensor is used for obtaining the water supply temperature, the water return temperature sensor is used for obtaining the water return temperature, and the water supply and return temperature difference is obtained through the water supply temperature and the water return temperature.
The method specifically comprises the steps of obtaining water supply temperature, obtaining water return temperature, obtaining water supply and return temperature difference through the water supply temperature and the water return temperature, controlling the frequency and the flow of cooling water pumps according to the preset relation between the water supply and return temperature difference and the frequency and the flow of the cooling water pumps, wherein at least two cooling water pumps are connected in parallel, the frequency and the flow of the cooling water pumps are obtained through an upper computer monitoring system according to the preset relation between the water supply and return temperature difference and the frequency and the flow of the cooling water pumps and are sent to a P L C control cabinet, the P L C control cabinet is connected with the cooling water pumps, and the frequency and the flow of the cooling water pumps are controlled through a P L C control cabinet.
Specifically, the temperature difference between cooling/freezing water supply and return water is 5 ℃ as a target value, the temperature difference is higher than 5 ℃, the frequency of a water pump is increased, and the flow of the water pump is increased; the temperature difference is less than 5 ℃, the water pump frequency is reduced, and the water pump flow is reduced.
The refrigerating water pump has large flow, long pipeline and large inertia of the system, so the worst pressure difference set value at the tail end of the system is adopted as a target value, and when the pressure difference load at the tail end of the system changes, the tail end temperature control system can automatically adjust the electric regulating valve at the tail end conventionally to cause the change of the pressure difference at the tail end, so the frequency and the flow of the refrigerating water pump are controlled according to the pressure difference at the tail end of the system. Wherein the system end differential pressure is obtained by a pressure sensor.
The control strategy of the chilled water pump comprises the steps of obtaining the pressure difference at the tail end of the system, and controlling the frequency and the flow of the chilled water pumps according to the preset relation between the pressure difference at the tail end of the system and the frequency and the flow of the chilled water pumps, wherein at least two chilled water pumps are connected in parallel, the chilled water pumps connected in parallel are connected with a cold water host machine and then connected with a cooling water pump connected in parallel, and the cooling water pumps connected in parallel are connected with a cooling tower, wherein the frequency and the flow of the chilled water pumps are obtained by an upper computer monitoring system according to the preset relation between the pressure difference at the tail end of the system and the frequency and the flow of the chilled water pumps and are sent to a P L C control cabinet, the P L C control cabinet is connected with the chilled water pumps, and the P L C control cabinet.
Specifically, when the pressure difference at the tail end of the system is increased to a pressure difference target value, the frequency of the water pump is increased, and the flow of the water pump is increased; when the pressure difference at the tail end of the system is reduced to a pressure difference target value, the frequency of the water pump is reduced, and the flow of the water pump is reduced.
In addition, the method further comprises: detecting the running time of a freezing water pump or a cooling water pump, and detecting the flow of the freezing water pump or the cooling water pump; judging whether the running time of the chilled water pump or the cooling water pump reaches a target time value or not, and simultaneously detecting that the flow of the chilled water pump or the cooling water pump reaches the target time value; and when the time detector detects that the running time of the chilled water pump or the cooling water pump reaches a target time value and the flow of the chilled water pump or the cooling water pump does not reach a target flow value, increasing the number of the chilled water pumps or the cooling water pumps.
The method further comprises the following steps: and performing PID control on the running freezing water pump or cooling water pump according to the temperature difference of the supplied water and the returned water. The PID control is critical to measuring the actual value of the controlled variable, and using this deviation to correct the response of the system, as compared to the desired value, to perform the regulatory control. Specifically, after the frequency of a single running water pump is maintained in a full working condition and runs for a certain preset time, for example, 10min, the system considers that the running water pump cannot meet the requirement of the tail end on the flow, at this time, a program sends an instruction for increasing 1 water pump, the frequency is gradually increased from zero (increased to above the minimum frequency within 10 s), the frequency of the running water pump is gradually reduced along with the increase of the frequency of the water pump, when the same value is reached, the frequency of the running water pump is changed simultaneously, and the system performs uniform PID control on the frequency of the running water pump according to the temperature difference of the supplied water and the returned water.
The connection of the freezing water pump, the cooling water pump and the cold water main machine adopts parallel connection and common pipe, so that a water separator and a water collector are omitted, and the power of the freezing water pump and the cooling water pump is lowest; the equipment can be accurately controlled according to the control method, so that the energy consumption is reduced; the invention provides an operation strategy of the cold water main machine, an operation control strategy of the chilled water pump, an operation control strategy of the cooling water pump and an operation control strategy of the cooling tower, so that the use efficiency of each part is optimized, the lowest energy consumption of the cold water main machine, the chilled water pump, the cooling water pump and the cooling tower is ensured, and the energy efficiency of the whole refrigerating machine room can be improved; the invention realizes the automatic control and management of the refrigerating machine room equipment through the optimized control logic, prolongs the service life of the refrigerating machine room equipment, ensures the operation safety of the refrigerating machine room equipment, and further reduces the energy consumption cost and the operation and maintenance cost.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A system of a refrigeration machine room, characterized in that: the system comprises at least two cold water main machines, a cooling tower, at least two chilled water pumps, at least two cooling water pumps and a detection and control device;
at least two freezing water pumps are connected in parallel, at least two cold water hosts are connected in parallel, at least two cooling water pumps are connected in parallel, the freezing water pumps which are connected in parallel are connected with the cold water hosts which are connected in parallel and then connected with the cooling water pumps which are connected in parallel, and the cooling water pumps which are connected in parallel are connected with a cooling tower;
the detection and control device is used for detecting the temperature of cooling water, obtaining the load of the cold water host and obtaining the corresponding reduced temperature of the cooling water or the adjustment value of the load of the host according to the matching relation between the temperature of the cooling water and the load of the cold water host;
the detection and control device is also used for acquiring the water outlet temperature of the cooling tower and controlling the number and the frequency of fans of the cooling tower according to the preset relationship between the water outlet temperature of the cooling tower and the number and the frequency of the fans of the cooling tower;
the detection and control device is also used for acquiring a water supply and return temperature difference and controlling the frequency and the flow of the cooling water pump according to a preset relation between the water supply and return temperature difference and the frequency and the flow of the cooling water pump;
the detection and control device is also used for acquiring the pressure difference at the tail end of the system and controlling the frequency and the flow of the chilled water pump according to the preset relation between the pressure difference at the tail end of the system and the frequency and the flow of the chilled water pump.
2. A system of a refrigeration room according to claim 1, characterized in that: the detection and control device comprises a cooling water temperature sensor and a load monitoring device, the cooling water temperature sensor is used for detecting the temperature of cooling water, the load monitoring device is used for obtaining the load of the cold water host, and the temperature of the cooling water is the temperature of the water cooled by the cold water host.
3. A system of a refrigeration room according to claim 1, characterized in that: the detection and control device also comprises an outlet water temperature sensor, and the outlet water temperature sensor is used for acquiring the outlet water temperature of the cooling tower;
the detection and control device further comprises a water supply temperature sensor and a water return temperature sensor, the water supply temperature sensor is used for obtaining water supply temperature, the water return temperature sensor is used for obtaining water return temperature, and the water supply temperature and the water return temperature are used for obtaining the water supply and return temperature difference.
4. A system of a refrigeration room according to claim 3, characterized in that: the detection and control device further comprises a time detector and a flowmeter, wherein the time detector is used for detecting the running time of the chilled water pump or the cooling water pump, and the flowmeter is used for detecting the flow of the chilled water pump or the cooling water pump;
the detection and control device is also used for increasing the number of the chilled water pumps or the cooling water pumps when the time detector detects that the running time of the chilled water pumps or the cooling water pumps reaches a target time value and the flow of the chilled water pumps or the cooling water pumps does not reach a target flow value.
5. A system of a refrigeration room according to claim 4, characterized in that: the detection and control device also comprises a PID controller, and the PID controller performs PID control on the running freezing water pump or the running cooling water pump according to the water supply and return temperature difference.
6. A control method of a refrigerating machine room is characterized in that:
detecting the temperature of cooling water, obtaining the load of a cold water host, and obtaining the corresponding reduced temperature of the cooling water or the adjustment value of the load of the host according to the matching relation between the temperature of the cooling water and the load of the cold water host; the number of the cold water main machines is at least two, and the at least two cold water main machines are connected in parallel;
acquiring the outlet water temperature of the cooling tower, and controlling the number and frequency of fans of the cooling tower according to the preset relationship between the outlet water temperature of the cooling tower and the number and frequency of the fans of the cooling tower;
acquiring a temperature difference between supply water and return water, and controlling the frequency and the flow of the cooling water pump according to a preset relation between the temperature difference between the supply water and the return water and the frequency and the flow of the cooling water pump; the number of the cooling water pumps is at least two, and the at least two cooling water pumps are connected in parallel;
acquiring a system tail end pressure difference, and controlling the frequency and the flow of the chilled water pump according to a preset relation between the system tail end pressure difference and the frequency and the flow of the chilled water pump; the number of the freezing water pumps is at least two, the at least two freezing water pumps are connected in parallel, the freezing water pumps connected in parallel are connected with the cold water main machine connected in parallel and then connected with the cooling water pumps connected in parallel, and the cooling water pumps connected in parallel are connected with the cooling tower.
7. The control method of the refrigerating machine room according to claim 6, wherein: the cooling water temperature is the temperature of the water cooled by the cold water host.
8. The control method of the refrigerating machine room according to claim 6, wherein: and acquiring a water supply temperature and a water return temperature, and acquiring the water supply and return temperature difference through the water supply temperature and the water return temperature.
9. The control method of the refrigerating machine room according to claim 8, wherein: detecting the running time of the chilled water pump or the cooling water pump, and simultaneously detecting the flow of the chilled water pump or the cooling water pump;
and when the time detector detects that the running time of the chilled water pumps or the cooling water pumps reaches a target time value and the flow of the chilled water pumps or the cooling water pumps does not reach a target flow value, increasing the number of the chilled water pumps or the cooling water pumps.
10. The control method of the refrigerating machine room according to claim 9, wherein: and performing PID control on the running freezing water pump or cooling water pump according to the temperature difference of the supplied water and the returned water.
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| CN202010182582.5A CN111442438A (en) | 2020-03-16 | 2020-03-16 | System and control method for refrigerating machine room |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112146247A (en) * | 2020-08-18 | 2020-12-29 | 同济大学 | Control method and system for parallel connection of multiple same-model variable-frequency freezing water pumps |
| CN112393345A (en) * | 2020-11-30 | 2021-02-23 | 珠海格力电器股份有限公司 | Water pump frequency control method and device, evaporative cooler and air conditioning system |
| CN112432269A (en) * | 2020-11-27 | 2021-03-02 | 上海碳索能源服务股份有限公司 | Method and system for optimizing set value of pressure difference of refrigerating water pump of refrigerating room |
| CN114340299A (en) * | 2020-09-30 | 2022-04-12 | 维谛技术有限公司 | Refrigeration station system and control method |
| CN115218714A (en) * | 2022-07-25 | 2022-10-21 | 贵州汇通华城股份有限公司 | Control device and method for heat exchanger |
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- 2020-03-16 CN CN202010182582.5A patent/CN111442438A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112146247A (en) * | 2020-08-18 | 2020-12-29 | 同济大学 | Control method and system for parallel connection of multiple same-model variable-frequency freezing water pumps |
| CN112146247B (en) * | 2020-08-18 | 2022-02-15 | 同济大学 | Control method and system for parallel connection of multiple same-model variable-frequency freezing water pumps |
| CN114340299A (en) * | 2020-09-30 | 2022-04-12 | 维谛技术有限公司 | Refrigeration station system and control method |
| CN112432269A (en) * | 2020-11-27 | 2021-03-02 | 上海碳索能源服务股份有限公司 | Method and system for optimizing set value of pressure difference of refrigerating water pump of refrigerating room |
| CN112393345A (en) * | 2020-11-30 | 2021-02-23 | 珠海格力电器股份有限公司 | Water pump frequency control method and device, evaporative cooler and air conditioning system |
| CN112393345B (en) * | 2020-11-30 | 2022-04-22 | 珠海格力电器股份有限公司 | Water pump frequency control method and device, evaporative cooler and air conditioning system |
| CN115218714A (en) * | 2022-07-25 | 2022-10-21 | 贵州汇通华城股份有限公司 | Control device and method for heat exchanger |
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