CN113983675B - Bypass differential pressure variable frequency air conditioner chilled water adjusting system and hydraulic balance method thereof - Google Patents
Bypass differential pressure variable frequency air conditioner chilled water adjusting system and hydraulic balance method thereof Download PDFInfo
- Publication number
- CN113983675B CN113983675B CN202111327458.4A CN202111327458A CN113983675B CN 113983675 B CN113983675 B CN 113983675B CN 202111327458 A CN202111327458 A CN 202111327458A CN 113983675 B CN113983675 B CN 113983675B
- Authority
- CN
- China
- Prior art keywords
- flow
- pump
- primary pump
- water
- bypass
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
- F24F11/63—Electronic processing
- F24F11/64—Electronic processing using pre-stored data
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Fuzzy Systems (AREA)
- Mathematical Physics (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The application relates to a bypass differential pressure variable frequency regulating air conditioner chilled water system and a hydraulic balance method thereof. According to the application, the hydraulic balance is performed through the quantitative calculation based on the hydraulic model, so that the control frequency of the water pump is accurately found, the primary pump and the secondary pump can work in an optimal state, the hydraulic balance requirement of the whole system including the least adverse users is met, the traditional valve control is replaced, the hydraulic oscillation or water hammer phenomenon caused by opening and closing the valve is avoided, and the working efficiency of the air conditioner chilled water system is improved.
Description
Technical Field
The application relates to the field of energy transportation, in particular to a bypass differential pressure variable frequency regulation air conditioner chilled water system and a hydraulic balance method thereof.
Background
Existing air conditioning water systems can be largely divided into a primary pump variable flow system and a primary pump constant flow system. For the continuously-changing load of the user side, the once pump constant flow system adapts to the change of the user side by changing the temperature of the water supply and return, so that the problems of large flow, small temperature difference and the like can be generated, the energy consumption of the system is always at the rated maximum value, and the energy conservation of the system is not utilized. The primary pump variable flow system adapts to the change of the user side by changing the flow of the system, and when the load of the user side is reduced, the flow of the system is reduced, so that the energy consumption of the system is reduced.
In general, the flow rate to the user side can be controlled by setting a bypass valve, or the frequency of the primary pump can be changed by setting the pressure difference of the water supply and return, so that the requirement of the user side can be met. The principle of realizing variable flow through the bypass valve is that a flow sensor is arranged between the water separator and the water collector, and the difference between the flow of a user and the minimum flow of the refrigerating water unit is used as the basis for controlling the opening of the bypass valve. When the user flow is smaller than the minimum flow of the refrigerating water unit, the bypass valve is opened, and the opening of the valve is controlled so that the flow passing through the valve is equal to the difference between the minimum flow of the refrigerating water unit and the user flow; when the user flow is greater than or equal to the minimum flow of the refrigeration water unit, the bypass valve is closed, so that the flow of the refrigeration water unit is ensured to be supplied to the user side. However, in the actual running process of the system, the opening and closing of the valve can cause phenomena such as hydraulic oscillation and water hammer, so that abnormal change of the system pressure can adversely affect the safe running of the system, and because the system lacks regular maintenance, many bypass valves cannot work normally, so that the flow and heat requirements of a user side cannot be ensured. The working principle of the method for setting the pressure difference of the water supply and return is that a pressure difference sensor is arranged at a proper position of a water supply and return pipe of the system, and when the flow rate of a user side changes, the water pump is driven to operate in a variable speed mode according to the data measured by the pressure difference sensor, so that the water outlet pressure of the water pump meets the set value of the pressure difference of the water supply and return. Therefore, the set value and the set position of the pressure difference of the water supply and return are critical, and the phenomenon that the side pressure of a user cannot meet the requirement or the water return flows back is caused by improper site selection or improper set value.
Disclosure of Invention
The application aims to overcome the defects in the prior art and provides a bypass differential pressure variable frequency regulating air conditioner chilled water system and a hydraulic balance method thereof.
The aim of the application can be achieved by the following technical scheme:
a bypass differential pressure variable frequency regulated air conditioner chilled water system, comprising: the system comprises user side equipment, a variable frequency control module, a water collector, a bypass pipe and a pressure sensor;
the user side equipment is connected in parallel and connected to the water diversity device; a bypass pipe is arranged in the middle of the water collecting and distributing device, and a pressure sensor is arranged and used for monitoring the pressure difference between the water supply and return main pipes.
The air conditioner secondary pump chilled water system also comprises a primary pump and a secondary pump; the primary pump is responsible for meeting the pressure requirement of a bypass loop of the water chilling unit; the secondary pump is used for meeting the pressure requirement of the least adverse user, and the surplus pressure of other users is controlled by setting a valve;
a variable frequency control module is arranged between the primary pump and the secondary pump and is used for controlling the pressure based on hydraulic balance; the frequency conversion control module is used for controlling the side pressure of a user.
Further, the variable frequency control module is used for controlling the side pressure of the user by adjusting the primary pump and the secondary pump based on the determined frequency.
Furthermore, the system is suitable for an air conditioner secondary pump chilled water system of a high-rise building.
Furthermore, the water chilling unit adopts a variable flow water chilling unit.
A bypass differential pressure variable frequency regulation air conditioner chilled water system hydraulic balance method comprises the following steps:
step S1: establishing and checking a pipe network hydraulic model;
step S2: determining the flow rate of a user side;
step S3: determining bypass flow;
step S4: determining a bypass pressure differential;
step S5: determining a lowest frequency of the primary pump;
step S6: determining the frequency of the primary pump and the secondary pump;
step S7: the frequency control of the primary pump and the secondary pump is performed based on the determined frequencies of the primary pump and the secondary pump.
Further, the user-side traffic is calculated from measured data or a load prediction model established based on historical operating data.
Further, in step S5, the lowest frequency of the primary pump is obtained when the user flow rate is equal to the minimum flow rate of the chiller.
Further, the step S1 includes:
step S101: and establishing a pipe network hydraulic model according to the pipe network CAD base map of the chilled water system, the user load condition and the basic equipment data in the system.
Step S102: and performing simulation calculation and check on the pipe network model based on the historical running data of the chilled water system.
Further, device and user data device samples or historical operating data are obtained.
The control platform comprises an intelligent building control server and the bypass pressure difference variable frequency regulating air conditioner chilled water system; the variable frequency control module is used for controlling the frequency of the primary pump and the secondary pump under the control instruction of the intelligent building control server.
Compared with the prior art, the application has the advantages and positive effects that:
1. the hydraulic balance is performed through quantitative calculation based on the hydraulic model, so that the control frequency of the water pump is accurately found, the primary pump and the secondary pump can work in an optimal state, the hydraulic balance requirement of the whole system including the most adverse users is met, the traditional valve control is replaced, the phenomenon of hydraulic oscillation or water hammer caused by opening and closing of the valve is avoided, and the working efficiency of an air conditioner chilled water system is improved.
2. The primary pump and the secondary pump are controlled independently and mutually restricted, the primary pump only needs to be responsible for the pressure requirement of the bypass loop, the pressure of the user side is met through the boosting of the secondary pump, and the backwater backflow phenomenon is not generated.
Drawings
Fig. 1 is a schematic diagram of a bypass differential pressure variable frequency regulation air conditioner chilled water system provided by the application.
Fig. 2 is a schematic diagram of a bypass differential pressure variable frequency regulating air conditioner chilled water system and a hydraulic balancing method thereof.
Fig. 3 is a schematic diagram of a primary pump operating state point of the bypass differential pressure variable frequency regulating air conditioner chilled water system and the hydraulic balancing method thereof.
Detailed Description
The application will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present application, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present application is not limited to the following examples.
The application provides a bypass differential pressure variable frequency regulating air conditioner chilled water system and a hydraulic balance method thereof, and the method belongs to a fixed dry pipe differential pressure control method; as shown in figure 1, the method is suitable for an air conditioner secondary pump chilled water system of a high-rise building.
The bypass differential pressure variable frequency regulating air conditioner chilled water system comprises: the system comprises user side equipment, a variable frequency control module, a water collector, a bypass pipe and a pressure sensor;
wherein: the variable frequency control module is used for controlling the side pressure of a user;
the user side equipment is connected in parallel and connected to the water diversity device; a bypass pipe is arranged in the middle of the water collecting and distributing device, and a pressure sensor is arranged and used for monitoring the pressure difference between the water supply and return main pipes.
The air conditioner secondary pump chilled water system also comprises a primary pump and a secondary pump; the primary pump is responsible for meeting the pressure requirement of a bypass loop of the water chilling unit; the secondary pump is used for meeting the pressure requirement of the least adverse user, and the surplus pressure of other users is controlled by setting a valve;
preferably; the surplus pressure is controlled by arranging an electric two-way valve;
a variable frequency control module is arranged between the primary pump and the secondary pump and is used for controlling the pressure based on hydraulic balance;
preferably: the variable frequency control module is used for executing the bypass differential pressure variable frequency adjustment air conditioner chilled water system hydraulic balance method.
Alternatively, the following is used: the variable frequency control module is used for controlling the frequency of the primary pump and the secondary pump under the control instruction of the intelligent building control server so as to control the pressure based on hydraulic balance; the intelligent building control server is used for executing the bypass differential pressure variable frequency regulation air conditioner chilled water system hydraulic balance method;
further, in the secondary pump chilled water system, a variable flow water chiller is adopted as the water chiller.
Based on the same inventive concept, the application provides a bypass differential pressure variable frequency regulating air conditioner chilled water system and a hydraulic balance method thereof, as shown in figure 2, specifically comprising the following steps:
step S1: establishing and checking a pipe network hydraulic model; the method specifically comprises the following steps:
step S101: establishing a pipe network hydraulic model according to the pipe network CAD base map of the chilled water system, the user load condition and the basic equipment data in the system; wherein: the device and user data may be obtained from device samples or historical operating data of the system.
Step S102: performing simulation calculation and check on the pipe network model based on the historical running data of the chilled water system; the purpose of checking is to ensure that the communication topology, the heat loss, the roughness, the height and the equipment characteristics of the pipeline in the pipeline network model are the same as those of the real situation, so that accurate and reliable hydraulic data are provided for the follow-up variable frequency control of the water pump.
Step S2: determining the user side flow of the chilled water system; specific: the user side flow is calculated from measured data or from a load prediction model built from historical operating data.
Step S3: and determining the bypass pipe flow according to the formula (1) according to the user side flow and the minimum flow of the water chiller.
In general, in order to ensure safe operation of the water chiller, there is a minimum allowable flow rate of the water chiller, and when the chilled water flow rate is less than the lower limit of the allowable flow rate, the water chiller starts self-protection and stops working. Therefore, when the flow rate of the user side is smaller than the minimum allowable flow rate of the water chilling unit, the rest chilled water is bypassed through the bypass pipe; when the user side flow is larger than the minimum allowable flow of the water chilling unit, the bypass pipe does not bypass, and the flow is 0. The bypass flow can thus be determined according to equation (1).
Wherein: q (Q) Side by side : bypass flow, m 3 /h；；Q min : the minimum flow permitted by the water chilling unit, m 3 /h；；Q max : upper limit of flow of water chilling unit, m 3 /h；；Q By using : user side traffic, m 3 /h。
Step S4: the bypass pressure differential deltap is determined. The method comprises the following steps: calculating a bypass pressure difference Δp based on the following formula;
ΔP＝SQ 2
wherein: Δp is the differential pressure of the bypass pipe, m; q is the flow of the bypass pipe, m 3 /h; the method comprises the steps of carrying out a first treatment on the surface of the S is the resistance coefficient of the bypass pipeline.
Because the bypass pipe between the water separators is provided with a pressure sensor, the bypass pressure difference can be used as a control signal for controlling the system pressure; the frequency of the primary pump needs to be changed to achieve the occurrence and measurement of the pressure difference. For example: the bypass pressure difference is set to 0 as the lower limit. When the bypass flow is greater than 0, the primary pump should change the frequency to ensure that the bypass pipe has enough pressure difference, so that the bypass flow and the user flow are distributed according to the requirement; when the bypass flow is equal to 0, the primary pump should change the frequency to ensure that the pressure difference of the bypass pipe is equal to 0, so that the pressure between the water supply and return pipes is equal, and no redundant chilled water directly flows back to the water chilling unit through the bypass loop, and no backwater backflow phenomenon is generated.
Step S5: the lowest frequency of the primary pump is determined. Specific: and obtaining the lowest frequency of the primary pump under the condition that the user flow is equal to the minimum flow of the water chiller.
The theoretical basis for realizing variable flow regulation of the variable-frequency water pump is derived from the law of similarity of the pump and the fan, and when the actual frequency f and the rated frequency f 0 At different times, the following relations exist among the flow, the lift and the frequency of the water pump:
H＝a(nQ) 2 +bknQ+ck 2 (2)
wherein: h: the actual lift, m of the water pump; q: actual flow of water pump, m 3 /h; k: water pump rotation speed ratio, k=f/f 0 The method comprises the steps of carrying out a first treatment on the surface of the Coefficients a, b, c, provided by manufacturer samples;
therefore, when the water pump flow and the water pump lift are known, the variable frequency of the water pump can be obtained through solving.
The method for determining the lowest frequency of the primary pump operation mainly comprises the following steps:
step S501: the user flow is enabled to be equal to the minimum flow of the water chilling unit, the bypass pipe flow is enabled to be equal to zero, the primary pump flow is the minimum flow of the water chilling unit, and the secondary pump flow is the user flow.
Step S502: inputting user flow, minimum flow of the water chilling unit, bypass flow, flow of the primary pump and the secondary pump, and enabling the secondary pump to lift h 2 Let the primary pump head be h =0 1 Calculating the pressure difference p of the bypass pipe by calling the pipe network hydraulic model 0 。
Step S503: judging the pressure difference p of the bypass pipe 0 Whether or not equal to zero, if yes, executing step S504; otherwise, step S505 is performed;
since the bypass pressure difference is equal to 0 when the bypass flow is equal to 0, the pressure between the water supply and return pipes is equal.
Step S504: inputting the pump lift h of the primary pump 1 And (3) calculating the primary pump frequency according to the formula (2), namely the primary pump operation minimum frequency.
Step S505: if the bypass pipe is pressure differential p 0 <0, increasing the lift of the primary pump; if p is 0 >And 0, reducing the pump lift once. Repeating steps S502 and S503 until the bypass pipe differential pressure p 0 ＝0。
Step S6: the frequencies of the primary and secondary pumps are determined.
The method for determining the frequency of the primary pump and the secondary pump mainly comprises the following steps:
step S601: adopting formulas (3) and (4), determining the flow of the primary pump and the secondary pump according to the flow of the user side, the flow of the water chilling unit and the flow of the bypass pipe:
Q secondary pump ＝Q By using (4)
Wherein: q (Q) Disposable pump For the flow of the primary pump, m 3 /h；Q Secondary pump Is the flow rate of the secondary pump, m 3 /h；
Step S602: inputting user flow, chiller flow, bypass flow, primary pump and secondary pump flow to make secondary pump lift h 2 Let the primary pump head be h =0 1 Calculating the pressure difference p of the bypass pipe by calling the pipe network hydraulic model 0 。
Step S603: judging whether the bypass pipe pressure difference determined according to the step S4 is consistent with the bypass pipe pressure difference obtained through the simulation calculation of the step S602, if so, executing the step S604; otherwise, step S606 is performed;
step S604: inputting the pump lift h of the primary pump 1 Calculating the frequency of the primary pump according to the formula (2), judging whether the frequency of the primary pump is greater than the minimum frequency of the primary pump, and if so, executing the step S607; otherwise, step S605 is executed.
Step S605: the number of primary pumps is increased, and the flow rate of a single primary pump is reduced; returning to step S602;
step S606: if the bypass pipe is pressure differential p 0 <0, increasing the lift of the primary pump; if the bypass pipe is pressure differential p 0 >And 0, reducing the pump lift once. Returning to step S602;
step S607: and (3) enabling the lift of the secondary pump to be equal to the current maximum negative pressure of the user, calculating the frequency of the secondary pump according to the formula (2), and outputting a result.
Step S7: performing frequency control of the primary pump and the secondary pump based on the determined frequencies of the primary pump and the secondary pump;
preferably: setting the variable frequency control module, and controlling the frequencies of the primary pump and the secondary pump based on the determined frequencies of the primary pump and the secondary pump;
based on the same inventive concept, the application provides a primary pump variable frequency control method based on the bypass pressure difference variable frequency adjustment air conditioner chilled water system hydraulic balance method, and based on the adjustment method, the primary pump variable frequency control mode is mainly divided into the following three cases, and specifically, as shown in fig. 3: 0<Q By using <Q min 、Q By using ＝Q min 、Q By using ＝Q min ；
The primary pump variable frequency control method specifically comprises the following steps:
step SA1: detecting user traffic;
step SA2: determining the condition of the user flow, and determining the primary pump frequency and the number of water pumps based on the condition of the air;
①0<Q by using <Q min :
When the user flow is smaller than the minimum flow of the water chilling unit, the water chilling unit operates according to the working condition of the minimum flow, and the bypass pipe sets the flow to be Q min -Q By using The primary pump flow is the minimum flow of the water chilling unit, and the secondary pump flow is the user flow. At the moment, a hydraulic simulation model is called, bypass pressure difference is calculated, the lift of the primary pump meeting the condition is output, at the moment, the flow of the primary pump is the same as the minimum flow of the water chilling unit, and the primary pump frequency f is calculated by using a formula (2) 1 . The water pump operating point is located at point a in fig. 3.
②Q By using ＝Q min :
Along with the continuous increase of the user side flow, when the user flow is equal to the minimum flow of the water chilling unit, the water chilling unit still operates according to the working condition of the minimum flow, the bypass pipe flow is 0, and the primary pump flow is still the minimum flow of the water chilling unit. At the moment, a hydraulic simulation model is called, so that when the bypass pressure difference is 0, the primary pump lift meeting the condition is output, and the primary pump frequency f is calculated by using the formula (2) 2 . The water pump operating point is located at point B in fig. 3. Because the bypass pipeline has no flow at this time and the bypass pressure difference is 0, the pressure required by the primary pump is the lowest state in the operation process, thus f 2 The lowest frequency of the water pump is also used, and the frequency of the water pump under other working conditions must be greater than f 2 Otherwise, the number of water pumps needs to be increased.
③Q min <Q By using <Q max :
When the user flow is greater than the minimum flow of the water chilling unit, the water chilling unit still operates according to the flow working condition required by the user side, the bypass pipe flow is still 0, and the flows of the primary pump and the secondary pump are the user flow. At the moment, a hydraulic simulation model is called, and when the bypass pressure difference is 0, the primary pump lift meeting the condition is output and utilizedCalculating the primary pump frequency f according to the formula (2) x . As shown in FIG. 3, the water pump operating point is located at B x And (5) a dot. When the user flow increases to the upper limit Q of the water chilling unit flow max I.e. the primary pump flow rate also reaches Q max At this time, the water pump operating point is located at point C in FIG. 3, and the calculated operating frequency f C And is also the upper limit of the operating frequency of the water pump.
Step SA3: adjusting the primary pump frequency and the number of the water pumps based on the calculated number of the water pumps and the working frequency;
for the secondary pump, the secondary pump flow is the total flow at the user side, and the lift is the pressure required by the least utilized user equipment end at the user side. The control target of the secondary pump is that the frequency of the secondary pump can be calculated through the flow and the lift of the secondary pump. The secondary pump changes frequency to ensure the pressure requirements of the least adverse user. The hydraulic simulation model also recalculates the pressure conditions at each user side once every time the user flow is updated. In each flow update calculation, the lift of the secondary pump is assumed to be zero. The calculation of the secondary pump head is performed with the primary pump head meeting the requirements. At this time, the secondary pump head is the maximum negative pressure of the user in the case of the primary pump head satisfying the condition. The flow of the secondary pump is the total flow of the user side, the lift is the pressure required by the tail end of the least-utilized user equipment, and the frequency of the secondary pump under the corresponding working condition can be obtained by solving the formula (2).
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present application and not for limiting the same, and although the present application has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the application without departing from the spirit and scope of the application, which is intended to be covered by the claims.
Claims (6)
1. A bypass differential pressure variable frequency regulating air conditioner chilled water system hydraulic balance method is characterized in that: the method comprises the following steps:
step S1: establishing and checking a pipe network hydraulic model; the method specifically comprises the following steps:
step S2: determining the user side flow of the chilled water system; specific: the user side flow is calculated from measured data or a load prediction model established according to historical operation data;
step S3: determining the bypass pipe flow according to a formula (1) according to the user side flow and the minimum flow of the water chiller;
；
wherein: q (Q) Side by side : bypass flow, m 3 /h；Q min : the minimum flow permitted by the water chilling unit, m 3 /h；Q max : upper limit of flow of water chilling unit, m 3 /h；Q By using : user side traffic, m 3 /h；
Step S4: determining bypass pressure differential p 0 The method comprises the steps of carrying out a first treatment on the surface of the The method comprises the following steps: the bypass pressure difference p is calculated based on the following formula 0 ；p 0 ＝SQ Side by side 2 ；p 0 Is the pressure difference of the bypass pipe, m; s is the resistance coefficient of the bypass pipeline;
step S5: determining a lowest frequency of the primary pump; specific: the lowest frequency of the primary pump is obtained under the condition that the flow rate of the user side is equal to the minimum flow rate of the water chilling unit; when the actual frequency f and the rated frequency f 0 At different times, the following relations exist among the flow, the lift and the frequency of the water pump: h=a (nQ) 2 +bknQ+ck 2 (2) The method comprises the steps of carrying out a first treatment on the surface of the Wherein: h: the actual lift, m of the water pump; q: actual flow of water pump, m 3 /h; k: water pump rotation speed ratio, k=f/f 0 The method comprises the steps of carrying out a first treatment on the surface of the Coefficients a, b, c, provided by manufacturer samples;
the method for determining the lowest frequency of the primary pump operation mainly comprises the following steps:
step S501: the user side flow is enabled to be equal to the minimum flow of the water chilling unit, the bypass pipe flow is enabled to be equal to zero, the primary pump flow is the minimum flow of the water chilling unit, and the secondary pump flow is the user side flow;
step S502: inputting user side flow, minimum flow of water chilling unitThe flow of the bypass pipe, the flow of the primary pump and the secondary pump, and the lift h of the secondary pump 2 Let the primary pump head be h =0 1 The pipe network hydraulic model is called to calculate the pressure difference p of the bypass pipe 0 ；
Step S503: judging the pressure difference p of the bypass pipe 0 Whether or not equal to zero, if yes, executing step S504; otherwise, step S505 is performed;
step S504: inputting the pump lift h of the primary pump 1 Calculating the primary pump frequency according to the formula (2), namely the lowest primary pump operation frequency;
step S505: if the bypass pipe is pressure differential p 0 <0, increasing the lift of the primary pump; if p is 0 >0, reducing the lift of the primary pump; repeating steps S502 and S503 until the bypass pipe differential pressure p 0 ＝0；
Step S6: determining the frequency of the primary pump and the secondary pump; the method specifically comprises the following steps:
step S601: adopting formulas (3) and (4), determining the flow of the primary pump and the secondary pump according to the flow of the user side, the flow of the water chilling unit and the flow of the bypass pipe:
；
Q secondary pump ＝Q By using (4)；
Wherein: q (Q) Disposable pump For the flow of the primary pump, m 3 /h；Q Secondary pump Is the flow rate of the secondary pump, m 3 /h；
Step S602: inputting user side flow, chiller flow, bypass flow, primary pump and secondary pump flow to make secondary pump lift h 2 Let the primary pump head be h =0 1 Calculating the pressure difference p of the bypass pipe by calling the pipe network hydraulic model 0 ；
Step S603: judging whether the bypass pipe pressure difference determined according to the step S4 is consistent with the bypass pipe pressure difference obtained through the simulation calculation of the step S602, if so, executing the step S604; otherwise, step S606 is performed;
step S604: inputting the pump lift h of the primary pump 1 Calculated according to the formula (2)The frequency of the primary pump is determined whether the primary pump frequency is greater than the lowest frequency of its operation, and if so, step S607 is performed; otherwise, step S605 is executed;
step S605: the number of primary pumps is increased, and the flow rate of a single primary pump is reduced; returning to step S602;
step S606: if the bypass pipe is pressure differential p 0 <0, increasing the lift of the primary pump; if the bypass pipe is pressure differential p 0 >0, reducing the lift of the primary pump; returning to step S602;
step S607: enabling the lift of the secondary pump to be equal to the current maximum negative pressure of a user, calculating the frequency of the secondary pump according to a formula (2), and outputting a result;
step S7: the frequency control of the primary pump and the secondary pump is performed based on the above-determined frequencies of the primary pump and the secondary pump.
2. The method according to claim 1, characterized in that: the step S1 includes:
step S101: establishing a pipe network hydraulic model according to the pipe network CAD base map of the chilled water system, the user load condition and the basic equipment data in the system;
step S102: and performing simulation calculation and check on the pipe network model based on the historical running data of the chilled water system.
3. A bypass differential pressure variable frequency regulated air conditioner chilled water system based on the hydraulic balancing method of any one of the preceding claims 1-2, characterized in that the system comprises: the system comprises user side equipment, a variable frequency control module, a water collector, a bypass pipe and a pressure sensor;
the user side equipment is connected in parallel and connected to the water diversity device; a bypass pipe is arranged in the middle of the water collecting and distributing device, and a pressure sensor is arranged and used for monitoring the pressure difference between the water supply and return main pipes;
the air conditioner chilled water system further comprises a primary pump and a secondary pump; the primary pump is responsible for meeting the pressure requirement of a bypass loop of the water chilling unit; the secondary pump is used for meeting the pressure requirement of the least adverse user, and the surplus pressure of other users is controlled by setting a valve;
a variable frequency control module is arranged between the primary pump and the secondary pump and is used for controlling the pressure based on hydraulic balance; the frequency conversion control module is used for controlling the side pressure of a user.
4. A system according to claim 3, characterized in that: the variable frequency control module is used for controlling the side pressure of a user by adjusting the primary pump and the secondary pump based on the determined frequency.
5. The system according to claim 4, wherein: the air conditioner secondary pump chilled water system is suitable for high-rise buildings.
6. A system according to claim 3, characterized in that: the water chiller adopts a variable flow water chiller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111327458.4A CN113983675B (en) | 2021-11-10 | 2021-11-10 | Bypass differential pressure variable frequency air conditioner chilled water adjusting system and hydraulic balance method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111327458.4A CN113983675B (en) | 2021-11-10 | 2021-11-10 | Bypass differential pressure variable frequency air conditioner chilled water adjusting system and hydraulic balance method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113983675A CN113983675A (en) | 2022-01-28 |
| CN113983675B true CN113983675B (en) | 2023-10-10 |
Family
ID=79747716
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111327458.4A Active CN113983675B (en) | 2021-11-10 | 2021-11-10 | Bypass differential pressure variable frequency air conditioner chilled water adjusting system and hydraulic balance method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113983675B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118031383B (en) * | 2024-03-18 | 2024-09-03 | 广东普而通科技有限公司 | Dynamic analysis algorithm for chilled water balance |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1318719A (en) * | 2000-04-14 | 2001-10-24 | 天津美新建筑设计有限公司 | Variable pressure difference and variable flow rate control method and system for air conditioning water system |
| CN2630717Y (en) * | 2003-07-18 | 2004-08-04 | 戴军 | Energy-saving control device for central air conditioning system |
| CN1598427A (en) * | 2004-09-09 | 2005-03-23 | 贵州汇诚科技有限公司 | Method for fuzzy expected controlling cold water system of central air conditioner |
| CN202598765U (en) * | 2012-06-01 | 2012-12-12 | 武汉裕生智能节能设备有限公司 | Optimized control device of variable primary flow system |
| JP2014035090A (en) * | 2012-08-07 | 2014-02-24 | Daikin Ind Ltd | Air conditioning system |
| CN204987368U (en) * | 2015-09-01 | 2016-01-20 | 湖南集森节能环保科技有限公司 | Refrigerated water pump package energy -saving control system |
| CN206369306U (en) * | 2017-01-09 | 2017-08-01 | 深圳市海源节能科技有限公司 | Once and secondary pump variable volume energy-saving control system |
| CN206377791U (en) * | 2017-01-11 | 2017-08-04 | 奥意建筑工程设计有限公司 | A kind of central air-conditioning two stage pump air-conditioner water system |
| CN108006928A (en) * | 2017-12-20 | 2018-05-08 | 武汉捷高技术有限公司 | Air conditioning water system vari- able flow control system and method |
| CN111089371A (en) * | 2019-12-13 | 2020-05-01 | 南京卓恒科技有限公司 | Electronic factory building cold source station control system and control method thereof |
| CN112254237A (en) * | 2020-09-21 | 2021-01-22 | 无锡混沌能源技术有限公司 | Air conditioner circulating water system pressure difference control system |
-
2021
- 2021-11-10 CN CN202111327458.4A patent/CN113983675B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1318719A (en) * | 2000-04-14 | 2001-10-24 | 天津美新建筑设计有限公司 | Variable pressure difference and variable flow rate control method and system for air conditioning water system |
| CN2630717Y (en) * | 2003-07-18 | 2004-08-04 | 戴军 | Energy-saving control device for central air conditioning system |
| CN1598427A (en) * | 2004-09-09 | 2005-03-23 | 贵州汇诚科技有限公司 | Method for fuzzy expected controlling cold water system of central air conditioner |
| CN202598765U (en) * | 2012-06-01 | 2012-12-12 | 武汉裕生智能节能设备有限公司 | Optimized control device of variable primary flow system |
| JP2014035090A (en) * | 2012-08-07 | 2014-02-24 | Daikin Ind Ltd | Air conditioning system |
| CN204987368U (en) * | 2015-09-01 | 2016-01-20 | 湖南集森节能环保科技有限公司 | Refrigerated water pump package energy -saving control system |
| CN206369306U (en) * | 2017-01-09 | 2017-08-01 | 深圳市海源节能科技有限公司 | Once and secondary pump variable volume energy-saving control system |
| CN206377791U (en) * | 2017-01-11 | 2017-08-04 | 奥意建筑工程设计有限公司 | A kind of central air-conditioning two stage pump air-conditioner water system |
| CN108006928A (en) * | 2017-12-20 | 2018-05-08 | 武汉捷高技术有限公司 | Air conditioning water system vari- able flow control system and method |
| CN111089371A (en) * | 2019-12-13 | 2020-05-01 | 南京卓恒科技有限公司 | Electronic factory building cold source station control system and control method thereof |
| CN112254237A (en) * | 2020-09-21 | 2021-01-22 | 无锡混沌能源技术有限公司 | Air conditioner circulating water system pressure difference control system |
Non-Patent Citations (2)
| Title |
|---|
| "空调一次泵变流量冷冻水系统供回水压差PI^λ D^μ控制器参数整定及其调节性能的研究";程康;《制冷与空调（四川）》;20210813;第35卷(第3期);第295-304页 * |
| Diversity of energy-saving control strategy for a parallel chilled water pump based on variable differential pressure control in an air-conditioning system;Liu Xuefeng;《Energy》;20150831;第88卷;第718-733页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113983675A (en) | 2022-01-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107143001B (en) | A kind of variable-frequency variable-voltage intelligent water supply equipment and water-supply control | |
| CN115823706B (en) | Self-adaptive variable pressure difference energy-saving control system and method for primary pump | |
| CN109917646B (en) | System and method for optimizing operation of regional cooling and heating equipment | |
| CN105757851B (en) | A kind of chilled water variable-flow energy-saving control method and control system | |
| CN110793173B (en) | Frequency conversion control method of water pump based on dynamic change of the most unfavorable air conditioner terminal | |
| CN206360877U (en) | A kind of optimal control for energy saving system of variable frequency pump parallel running | |
| CN110107989A (en) | Small-sized based on chilled water return water temperature optimum set point determines frequency water cooler and becomes temperature control method of water | |
| CN112556098B (en) | Dynamic hydraulic balance control method | |
| CN1186572C (en) | Variable pressure difference and variable flow rate control method and system for air conditioning water system | |
| CN106642535B (en) | Control system and control method for cold station of central air conditioner | |
| CN106500280A (en) | Control system and control method for cold station of central air conditioner | |
| CN111980856A (en) | Load prediction-based frequency modulation control method for energy storage type hydraulic wind generating set | |
| CN201292954Y (en) | Water pump and/or blower fan highly effective energy-conserving control system | |
| JP6198398B2 (en) | Control method for determining the number of operating pumps in a two-pump heat source facility | |
| CN113983675B (en) | Bypass differential pressure variable frequency air conditioner chilled water adjusting system and hydraulic balance method thereof | |
| CN113446661B (en) | Intelligent and efficient heat supply network operation adjusting method | |
| CN113701321B (en) | Energy-saving frequency conversion control method for central air-conditioning water pump | |
| CN105864016A (en) | Variable-water-volume operation regulating method for open multi-water-pump transmission and distribution system | |
| CN114811714A (en) | Heating room temperature control method based on model predictive control | |
| Tianyi et al. | An optimal differential pressure reset strategy based on the most unfavorable thermodynamic loop on-line identification for a variable water flow air conditioning system | |
| KR20160017960A (en) | The optimal control method of inverter booster pump | |
| Ahonen et al. | Energy efficiency optimizing speed control method for reservoir pumping applications | |
| CN105221385A (en) | Air-conditioning system different lift different flow Combined water pump structure and controlling method | |
| CN107305055A (en) | A kind of frequency-changing control system of water pump of central air conditioner | |
| CN206387073U (en) | Control system of central air conditioning cold station |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: A bypass pressure difference variable frequency regulation air conditioning chilled water system and its hydraulic balance method Granted publication date: 20231010 Pledgee: Changning Sub Branch of Shanghai Rural Commercial Bank Co.,Ltd. Pledgor: Shanghai guanran Intelligent Technology Co.,Ltd. Registration number: Y2024310000160 |