Central air conditioner temperature control system and control method

Abstract

The invention relates to a central air conditioner temperature control system which comprises a water storage tank, a water chilling unit and a plurality of terminal coil pipes, a low-temperature water filling pipeline and a high-temperature water return pipeline are connected between the water storage tank and the water chilling unit, and the low-temperature water filling pipeline is provided with two low-temperature water filling stop valves and a low-temperature water filling pump. The high-temperature water return pipeline is provided with two high-temperature water return stop valves, the low-temperature water filling pipeline section between the two low-temperature water filling stop valves is connected with a low-temperature water distribution main pipeline, the water inlet end of the low-temperature water distribution main pipeline is connected with a low-temperature water distribution main valve, and the low-temperature water distribution main pipeline is connected with the terminal coil pipes through low-temperature water distribution branch pipelines. And each low-temperature water distribution branch is connected with a flow control valve. The optimal working parameter combination of the system can be quickly obtained, so that the energy efficiency of the central air conditioner temperature control system is improved, and energy conservation and environmental protection are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of central air-conditioning temperature control, and particularly relates to a central air-conditioning temperature control system and a control method thereof. Background Art

[0002] In order to achieve peak shaving and valley filling of power consumption and realize green energy conservation, the central air-conditioning temperature control system adopts a "low-temperature water filling mode" at night to fill cold water into a water storage tank for storage. During the day, the central air-conditioning temperature control system adopts a "water storage tank cooling mode" to input cold water into each terminal coil.

[0003] When operating in the "water storage tank cooling mode", a "stratified temperature layer" gradually appears in the water storage tank. If the "stratified temperature layer" becomes thicker, it will increase the heat loss of the water storage tank and reduce the energy storage efficiency of the water tank. Generally, the thickness of the stratified temperature layer should be kept within 1 m to enable the energy storage tank to have a high energy storage efficiency. The low-temperature water temperature, high-temperature water temperature, low-temperature water flow rate, and high-temperature water flow rate stored in the water storage tank jointly affect the rate of thickening of the "stratified temperature layer". On the other hand, size factors such as the ratio of the height to the diameter of the water storage tank itself also affect the rate of thickening of the "stratified temperature layer".

[0004] After replacing the water storage tank with different dimensions (or height-diameter ratio), the rate of thickening of its "stratified temperature layer" will change. In order to make the new water storage tank reach the minimum rate of thickening of the "stratified temperature layer" again, it is necessary to try different combinations of parameters such as low-temperature water temperature, high-temperature water temperature, low-temperature water flow rate, and high-temperature water flow rate, and try to find the optimal combination of the above parameters. Only in this way can the new water storage tank reach the minimum rate of thickening of the "stratified temperature layer" again. The above attempt process is time-consuming and has low efficiency, and it may not necessarily be able to find the optimal parameter combination. Summary of the Invention

[0005] The purpose of the present invention is to provide a central air-conditioning temperature control system and a control method thereof, which can quickly obtain the optimal working parameter combination of the system, so as to improve the energy efficiency of the central air-conditioning temperature control system and is beneficial to energy conservation and environmental protection.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A central air-conditioning temperature control system includes a water storage tank, a chiller, and several terminal coils. A low-temperature water filling pipeline and a high-temperature water return pipeline are connected between the water storage tank and the chiller. The low-temperature water filling pipeline is provided with two low-temperature water filling stop valves and a low-temperature water filling pump. The high-temperature water return pipeline is provided with two high-temperature water return stop valves. A low-temperature water distribution main pipeline is connected to the section of the low-temperature water filling pipeline between the two low-temperature water filling stop valves. The inlet end of the low-temperature water distribution main pipeline is connected with a low-temperature water distribution main valve. The low-temperature water distribution main pipeline and each terminal coil are connected through a low-temperature water distribution branch pipeline. Each low-temperature water distribution branch pipeline is connected with a flow control valve. The section of the high-temperature water return pipeline between the two high-temperature water return stop valves is connected with a high-temperature water confluence main pipeline. The outlet end of the high-temperature water confluence main pipeline is connected with a high-temperature water distribution main valve. The high-temperature water confluence main pipeline and each terminal coil are connected through a high-temperature water distribution branch pipeline. The high-temperature water distribution branch pipeline is connected with a branch water pump.

[0008] Specifically, a water thermometer is provided on the low-temperature water filling pipeline.

[0009] Specifically, a water thermometer is provided on the high-temperature water return pipeline.

[0010] Specifically, a flow meter is provided on the low-temperature water filling pipeline.

[0011] Specifically, a flow meter is provided on the high-temperature water return pipeline.

[0012] Specifically, a water thermometer is provided on each low-temperature water distribution branch pipeline.

[0013] Specifically, a water thermometer is provided on each high-temperature water distribution branch pipeline.

[0014] A control method applied to the control system is characterized by including the following steps:

[0015] Sensor mounting bracket arrangement step: Hoist and place a multi-layer concentric ring mounting bracket into the water storage tank. Each layer of the concentric ring mounting bracket is evenly provided with a plurality of flow velocity sensors, water pressure sensors, and water temperature sensors. Each layer of the concentric ring mounting bracket is arranged at intervals in the vertical direction, so that the distance between the highest concentric ring mounting bracket and the lowest concentric ring mounting bracket is greater than the maximum value of the thickness of the thermocline corresponding to the water storage tank;

[0016] Low-temperature water filling step: The chiller inputs low-temperature water through the bottom of the water storage tank until the entire water storage tank is filled;

[0017] The height position positioning step of the inclined temperature layer: the low-temperature water stored in the water storage tank is pumped to each terminal coil, and the low-temperature water becomes high-temperature water after passing through the terminal coil, and flows back to the top of the water storage tank through the high-temperature water return pipe, and the low-temperature water is discharged at the bottom of the water storage tank. At the same time, in the process of receiving high-temperature water at the top of the water storage tank, the water body in the water storage tank gradually forms an inclined temperature layer, and the cage is slowly suspended vertically from top to bottom. The water temperature sensors of the concentric ring mounting frames of each layer sense the water temperature at each height position in real time until two temperature mutations are sensed: the temperature mutation at the lower side is determined as the lower boundary of the inclined temperature layer, and the temperature mutation at the upper side is determined as the upper boundary of the inclined temperature layer;

[0018] Numerical sensing and simulation steps: The velocity sensor senses the velocity of each layer near the upper and lower boundaries of the thermocline layer in real time, and the velocity gradient tensor at the upper and lower boundaries of the thermocline layer is obtained by Kriging interpolation and radial basis function simulation. And measure the flow velocity u at the upper and lower boundaries of the thermocline layer 上界 、u 下界 ;

[0019] The water pressure sensor senses the water pressure of each layer near the upper and lower boundaries of the thermocline layer in real time, and the water pressure gradient tensor at the upper and lower boundaries of the thermocline layer is obtained by Kriging interpolation and radial basis function simulation. The water pressure p at the upper and lower boundaries of the thermocline layer is measured. 上界 、p 下界 The water temperature sensor measures the water temperature T at the upper and lower boundaries of the thermocline layer in real time. 上界 、T 下界 ;

[0020] Steps for combining equations: Substitute the upper boundary of the thermocline u 上界 , and the lower boundary of the thermocline u 下界 , Substitute them into the momentum equation as follows:

[0021]

[0022] By T 上界 The internal energy E at the upper boundary of the thermocline layer is calculated 上界 , through T 下界 The internal energy E at the lower boundary of the thermocline is calculated 下界 , then, the E at the upper boundary of the thermocline 上界 、u 上界 、p 上界 and E at the lower boundary of the thermocline 下界 、u 下界 、p 下界 Substitute them into the following energy equation:

[0023]

[0024] By simultaneously solving the momentum equation and the energy equation at the upper boundary of the thermocline, the temperature gradient at the upper boundary of the thermocline is obtained. By simultaneously solving the momentum equation and the energy equation at the lower boundary of the thermocline, the temperature gradient at the lower boundary of the thermocline is obtained.

[0025] Steps for analyzing the migration law of the thermocline: During the process of the water storage tank supplying cooling to each terminal coil, the upper and lower boundaries of the thermocline will gradually shift. Under any high-temperature water temperature T-high temperature water and any low-temperature water temperature T-low temperature water conditions, the height position where the upper boundary of the thermocline shifts is tracked and positioned in real time through the water temperature sensors on each layer of concentric ring mounting frames, and the real-time temperature gradient of the upper boundary of the thermocline under this water temperature condition is calculated. Obtain the real-time temperature gradient of the upper boundary of the thermocline under this water temperature condition. And the real-time flow rate F of the water discharged from the bottom of the tank 罐底出水 And the real-time flow rate F of the water entering the top of the tank 罐顶进水 The relationship curve between them. The relationship curves under different high-temperature water temperatures T-high temperature water and low-temperature water temperatures T-low temperature water conditions are collected to obtain a cluster of migration law curves of the upper boundary of the thermocline.

[0026] Under any high-temperature water temperature T-high temperature water and any low-temperature water temperature T-low temperature water conditions, the position where the lower boundary of the thermocline shifts is tracked and positioned in real time through the water temperature sensors on each layer of concentric ring mounting frames, and the real-time temperature gradient of the lower boundary of the thermocline under this water temperature condition is calculated. Obtain the real-time temperature gradient of the lower boundary of the thermocline under this water temperature condition. And the real-time flow rate F of the water discharged from the bottom of the tank 罐底出水 And the real-time flow rate F of the water entering the top of the tank 罐顶进水 The relationship curve between them. The relationship curves under different high-temperature water temperatures T-high temperature water and low-temperature water temperatures T-low temperature water conditions are collected to obtain a cluster of migration law curves of the lower boundary of the thermocline.

[0027] Integrate And And perform data analysis to obtain And When it is in a relatively small interval range, the corresponding high-temperature water temperature T-high temperature water interval and low-temperature water temperature T-low temperature water interval of the water storage tank are called the ideal high-temperature water temperature interval and the ideal low-temperature water temperature interval. The ideal high-temperature water temperature interval corresponds to an ideal water inflow rate interval at the top of the tank, and the ideal low-temperature water temperature interval corresponds to an ideal water discharge rate interval at the bottom of the tank.

[0028] Branch flow and terminal coil cooling capacity distribution steps: Establish a collaborative regulation mechanism for the cooling capacity of each terminal coil: When the bottom water outlet temperature is within the ideal low-temperature water temperature range and the top water inlet temperature is within the ideal high-temperature water temperature range, the cooling capacity of each terminal coil 3 meets the requirements. On this basis, establish a collaborative regulation mechanism for the flow rates of each inlet branch and each outlet branch: Make the total inflow of low-temperature water in each inlet branch fall within the ideal bottom water outlet flow rate range, and make the total outflow of high-temperature water in each outlet branch fall within the ideal top water inlet flow rate range.

[0029] Compared with the prior art, the beneficial effects of the present invention:

[0030] For different height-to-diameter ratios and sizes of the water storage tank 1, design a cage 7 and a concentric ring-shaped mounting frame 6 with corresponding sizes, so that the diameter of the outermost ring is corresponding to the inner diameter of the water storage tank 1.

[0031] Uniformly arrange a plurality of flow rate sensors, water pressure sensors and water temperature sensors on the outer wall of the concentric rings, and make the diameters of the ring bodies of the same-layer concentric ring-shaped mounting frame 6 increase in reasonable sizes, so as to ensure that the above sensors are evenly distributed in the same layer.

[0032] Lift the combination body composed of the cage 7 and the multi-layer concentric ring-shaped mounting frame 6 into the inner cavity of the water storage tank 1. First, lift the cage 7 to the upper part of the inner cavity of the water storage tank 1 (as Figure 1 shown, the thermocline generally forms in the upper part first, and the maximum thickness of the thermocline is generally 1 meter, that is, the distance between the highest-layer concentric ring-shaped mounting frame 6 and the lowest-layer concentric ring-shaped mounting frame 6 is greater than 1 meter).

[0033] Then, the water storage tank 1 operates in the above-mentioned mode two (water storage tank cooling mode). During the operation, a thermocline is generated between the low-temperature water and the high-temperature water in the water storage tank 1. The thermocline has a certain thickness. The interface between the thermocline and the high-temperature water is the upper boundary of the thermocline, and the interface between the thermocline and the low-temperature water is the lower boundary of the thermocline.

[0034] The densely arranged flow rate sensors, water pressure sensors and water temperature sensors near the corresponding height positions can measure the flow rates u 上界 、u 下界 at the upper boundary and the lower boundary of the thermocline, the water pressures p 上界 、p 下界 at the upper boundary and the lower boundary of the thermocline, and the water temperatures T 上界 、T 下界 at the upper boundary and the lower boundary of the thermocline. Through interpolation and simulation, the water pressure gradient tensors at the upper boundary and the lower boundary of the thermocline and the flow rate gradient tensors

[0035] Substituting the above values ​​into the momentum equation:

[0036]

[0037] Substituting the above values ​​into the energy equation:

[0038]

[0039] Combining the momentum equation and energy equation for the upper boundary of the thermocline, we can obtain Combining the momentum equation and energy equation at the lower boundary of the thermocline, we can obtain and The speed and direction of the axial displacement of the upper and lower boundaries of the thermocline layer are respectively indicated, which reflects the rate at which the thermocline layer becomes thicker.

[0040] By collecting the relationship curve clusters under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water and By integrating and analyzing them, the ideal high-temperature water temperature T-high-temperature water interval and low-temperature water temperature T-low-temperature water interval of the water tank 1 with the aspect ratio and size can be obtained, and the ideal tank top water inlet flow interval and the ideal tank bottom water outlet flow interval can be further obtained. In this way, the optimal operating condition corresponding to the water tank 1 with the aspect ratio and size can be quickly obtained, and mode two (water tank cooling mode) operation is carried out under the optimal operating condition, which can greatly save energy consumption and is conducive to green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 This is the system diagram of the central air-conditioning temperature control system;

[0043] Figure 2 It is a combination of a cage body and multi-layer concentric annular mounting frames;

[0044] Figure 3 It is a single-layer concentric ring mounting frame;

[0045] Figure 4 For the cage.

[0046] In the figure:

[0047] 1. Water storage tank; 2. Chiller; 21. Low-temperature water filling pipeline; 211. Low-temperature water filling stop valve; 212. Low-temperature water filling pump; 22. High-temperature water return pipeline; 221. High-temperature water return stop valve; 23. Low-temperature water distribution main line; 231. Low-temperature water distribution main valve; 24. Low-temperature water distribution branch line; 241. Flow control valve; 25. High-temperature water confluence main line; 26. High-temperature water distribution branch line; 261. Branch line pump

[0048] 3. Terminal coil

[0049] 4. Water thermometer

[0050] 5. Flowmeter

[0051] 6. Concentric ring mounting bracket

[0052] 7. Cage Detailed implementation mode

[0053] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments

[0054] See Figure 1 , a central air-conditioning temperature control system, including a water storage tank 1, a chiller 2 and a number of terminal coils 3. A low-temperature water filling pipeline 21 and a high-temperature water return pipeline 22 are connected between the water storage tank 1 and the chiller 2. The low-temperature water filling pipeline 21 is provided with two low-temperature water filling stop valves 211 and a low-temperature water filling pump 212. The high-temperature water return pipeline 22 is provided with two high-temperature water return stop valves 221

[0055] The section of the low-temperature water filling pipeline 21 between the two low-temperature water filling stop valves 211 is connected with a low-temperature water distribution main line 23, and the water inlet end of the low-temperature water distribution main line 23 is connected with a low-temperature water distribution main valve 231. The low-temperature water distribution main line 23 is connected with each terminal coil 3 through a low-temperature water distribution branch line 24, and each low-temperature water distribution branch line 24 is connected with a flow control valve 241

[0056] The section of the high-temperature water return pipeline 22 between the two high-temperature water return stop valves 221 is connected with a high-temperature water confluence main line 25, and the water outlet end of the high-temperature water confluence main line 25 is connected with a high-temperature water distribution main valve 251. The high-temperature water confluence main line 25 is connected with each terminal coil 3 through a high-temperature water distribution branch line 26, and the high-temperature water distribution branch line 26 is connected with a branch line pump 261

[0057] Specifically, the low-temperature water filling pipeline 21 is provided with a water thermometer 4

[0058] Specifically, the high-temperature water return pipeline 22 is provided with a water thermometer 4

[0059] Specifically, a flow meter 5 is provided on the low-temperature water filling pipeline 21.

[0060] Specifically, a flow meter 5 is provided on the high-temperature water return pipeline 22.

[0061] Specifically, a water temperature meter 4 is provided on each low-temperature water distribution branch 24.

[0062] Specifically, a water temperature meter 4 is provided on each high-temperature water distribution branch 26.

[0063] The central air-conditioning temperature control system has two working modes:

[0064] Mode 1: Low-temperature water filling mode

[0065] When the electricity price at night is relatively low, the chiller 2 is used for refrigeration and the cold is stored. Specifically: the low-temperature water distribution main valve 231 and the high-temperature water distribution main valve 251 are closed, the two low-temperature water filling stop valves 211 and the two high-temperature water return stop valves 221 are opened, and the low-temperature water produced by the chiller 2 is transported to the bottom of the water storage tank 1 through the low-temperature water filling pipeline 21 until the inside of the water storage tank 1 is filled with cold water.

[0066] Mode 2: Water storage tank cooling mode

[0067] When the electricity price during the day is relatively high, the chiller 2 is turned off and the water storage tank is used for cooling. Specifically: the right low-temperature water filling stop valve 211 in the low-temperature water filling pipeline 21 is closed, the right high-temperature water return stop valve 221 in the high-temperature water return pipeline 22 is closed, and the chiller 2 is shut down. Then, the low-temperature water distribution main valve 231 and the high-temperature water distribution main valve 251 are both opened. At this time, the low-temperature water at the bottom of the water storage tank 1 enters the low-temperature water distribution main pipeline 23 through the low-temperature water filling pipeline 21, then enters each terminal coil 3, then converges into the high-temperature water converging main pipeline 25, then enters the high-temperature water return pipeline 22, and then flows into the top of the water storage tank 1.

[0068] During the process of working in Mode 2, the liquid in the water storage tank 1 is gradually stratified, with low-temperature water at the lower layer and high-temperature water at the top layer, and a thermocline will be formed between the low-temperature water and the high-temperature water. On the premise of ensuring the normal operation of the terminal coil 3, selecting a reasonable flow rate and cooling capacity of the terminal coil 3 is beneficial to delaying the thickening of the thermocline, thereby improving the cold storage efficiency of the water storage tank 1. The control method is as follows:

[0069] Combined with Figures 2 to 4 , the control method applied to the control system includes the following steps:

[0070] Sensor mounting bracket arrangement step: Arrange the multi-layer concentric ring mounting bracket 6 (the multi-layer concentric ring mounting bracket 6 is mounted on the cage body 7 to form a combined body, such as Figure 2The concentric ring mounting frame 6 is suspended in the water storage tank 1, and the ring bodies of each layer of concentric ring mounting frame 6 are evenly arranged with multiple flow rate sensors, water pressure sensors and water temperature sensors. The concentric ring mounting frames 6 of each layer are arranged vertically at intervals, so that the distance between the highest concentric ring mounting frame 6 and the lowest concentric ring mounting frame 6 is greater than the maximum value of the thickness of the inclined temperature layer corresponding to the water storage tank 1. For the water storage tank, the maximum value of the thickness of the inclined temperature layer is 1m.

[0071] Low-temperature water filling steps: The chiller 2 inputs low-temperature water through the bottom of the water storage tank 1 until the entire water storage tank 1 is filled.

[0072] The step of locating the height position of the thermocline layer: the low-temperature water stored in the water tank 1 is pumped to each terminal coil 3, and the low-temperature water becomes high-temperature water after passing through the terminal coil 3, and flows back to the top of the water tank 1 through the high-temperature water return pipe 22. In the process of discharging low-temperature water from the bottom of the water tank 1 and receiving high-temperature water at the top of the water tank 1, the water body in the water tank 1 gradually forms a thermocline layer. The cage 7 is slowly suspended vertically from top to bottom, and the water temperature sensors of each layer of concentric annular mounting frames 6 sense the water temperature at each height position in real time until two temperature mutations are sensed: the temperature mutation located on the lower side is determined as the lower boundary of the thermocline layer, and the temperature mutation located on the upper side is determined as the upper boundary of the thermocline layer.

[0073] Numerical sensing and simulation steps: The velocity sensor senses the velocity of each layer near the upper and lower boundaries of the thermocline layer in real time, and the velocity gradient tensor at the upper and lower boundaries of the thermocline layer is obtained by Kriging interpolation and radial basis function simulation. And measure the flow velocity u at the upper and lower boundaries of the thermocline layer 上界 、u 下界 ;

[0074] The water pressure sensor senses the water pressure of each layer near the upper and lower boundaries of the thermocline layer in real time, and the water pressure gradient tensor at the upper and lower boundaries of the thermocline layer is obtained by Kriging interpolation and radial basis function simulation. The water pressure p at the upper and lower boundaries of the thermocline layer is measured. 上界 、p 下界 ;

[0075] The water temperature sensor measures the water temperature T at the upper and lower boundaries of the thermocline layer in real time. 上界 、T 下界 ;

[0076] Steps for combining equations: Substitute the upper boundary of the thermocline u 上界 , and the lower boundary of the thermocline u 下界 , Substitute them into the momentum equation as follows:

[0077]

[0078] Through T 上界 calculate the internal energy E at the upper boundary of the thermocline 上界 and through T 下界 calculate the internal energy E at the lower boundary of the thermocline 下界 Then, substitute E 上界 , u 上界 , p 上界 at the upper boundary of the thermocline and E 下界 , u 下界 , p 下界 at the lower boundary of the thermocline into the following energy equation respectively:

[0079]

[0080] Simultaneously solve the momentum equation and the energy equation at the upper boundary of the thermocline to obtain the temperature gradient at the upper boundary of the thermocline Simultaneously solve the momentum equation and the energy equation at the lower boundary of the thermocline to obtain the temperature gradient at the lower boundary of the thermocline

[0081] Analysis steps for the migration law of the thermocline: During the process of the water storage tank 1 supplying cooling to each terminal coil 3, the upper and lower boundaries of the thermocline will gradually shift. Under any high-temperature water temperature T-high temperature water and any low-temperature water temperature T-low temperature water conditions, the height position where the upper boundary of the thermocline offsets is tracked and positioned in real time through the water temperature sensors on each layer of the concentric ring mounting frame 6, and the real-time temperature gradient of the upper boundary of the thermocline is calculated under this water temperature condition Obtain the real-time temperature gradient of the upper boundary of the thermocline under this water temperature condition and the relationship curve with the real-time flow rate F of the water discharged from the bottom of the tank 罐底出水 and the real-time flow rate F of the water entering the top of the tank 罐底进水 Collect the relationship curves under different high-temperature water temperatures T-high temperature water and low-temperature water temperatures T-low temperature water conditions to obtain a cluster of offset law curves of the upper boundary of the thermocline

[0082] Under any high-temperature water temperature T-high temperature water and any low-temperature water temperature T-low temperature water conditions, the height position where the lower boundary of the thermocline offsets is tracked and positioned in real time through the water temperature sensors on each layer of the concentric ring mounting frame 6, and the real-time temperature gradient of the lower boundary of the thermocline is calculated under this water temperature condition Obtain the real-time temperature gradient of the lower boundary of the thermocline under this water temperature condition and the real-time flow rate F of the water discharged from the bottom of the tank 罐底出水 and the real-time flow rate F of the water entering the top of the tank 罐顶进水The relationship curves between them are integrated, and the relationship curves under different high-temperature water temperatures T - high-temperature water and low-temperature water temperatures T - low-temperature water conditions are collected to obtain a cluster of curves of the law of the lower boundary shift of the thermocline.

[0083] Integrate And And perform data analysis to obtain And When it is in a relatively small interval range, the high-temperature water temperature T - high-temperature water interval and the low-temperature water temperature T - low-temperature water interval of the water storage tank 1 are called the ideal high-temperature water temperature interval and the ideal low-temperature water temperature interval. The ideal high-temperature water temperature interval corresponds to an ideal top-inlet flow rate interval, and the ideal low-temperature water temperature interval corresponds to an ideal bottom-outlet flow rate interval.

[0084] Steps for branch flow and cooling capacity distribution of the terminal coil 3:

[0085] Establish a collaborative regulation mechanism for the cooling capacity of each terminal coil 3: When the bottom-outlet water temperature is in the ideal low-temperature water temperature interval and the top-inlet water temperature is in the ideal high-temperature water temperature interval, the cooling capacity of each terminal coil 3 meets the requirements. On this basis, establish a collaborative regulation mechanism for the flow rates of each inlet branch and each outlet branch: Make the total inflow of low-temperature water in each inlet branch be in the ideal bottom-outlet flow rate interval, and make the total outflow of high-temperature water in each outlet branch be in the ideal top-inlet flow rate interval.

[0086] The working principle of the above control method is:

[0087] For different height-diameter ratios and sizes of the water storage tank 1, design a cage 7 and a concentric ring-shaped mounting frame 6 with corresponding sizes, so that the diameter of the outermost ring is corresponding to the inner diameter of the water storage tank 1.

[0088] Uniformly arrange a plurality of flow rate sensors, water pressure sensors and water temperature sensors on the outer wall of the concentric rings, and make the diameters of the ring bodies of the same-layer concentric ring-shaped mounting frame 6 increase in reasonable sizes, so as to ensure that the above sensors are uniformly densely arranged in the same layer.

[0089] Lift the combination body composed of the cage 7 and the multi-layer concentric ring-shaped mounting frame 6 into the inner cavity of the water storage tank 1. First, lift the cage 7 to the upper part of the inner cavity of the water storage tank 1 (as Figure 1 shown, the thermocline generally forms in the upper part first, and the maximum thickness of the thermocline is generally 1 meter, that is, the distance between the highest-layer concentric ring-shaped mounting frame 6 and the lowest-layer concentric ring-shaped mounting frame 6 is greater than 1 meter).

[0090] Then, the water storage tank 1 operates in the above-mentioned mode 2 (water storage tank cooling mode). During the operation, a thermocline is generated between the low-temperature water and the high-temperature water in the water storage tank 1. The thermocline has a certain thickness. The interface between the thermocline and the high-temperature water is the upper boundary of the thermocline, and the interface between the thermocline and the low-temperature water is the lower boundary of the thermocline.

[0091] The densely arranged flow velocity sensors, water pressure sensors, and water temperature sensors near the corresponding height positions can measure the flow velocities u 上界 、u 下界 at the upper and lower boundaries of the thermocline, the water pressures p 上界 、p 下界 at the upper and lower boundaries of the thermocline, and the water temperatures T 上界 、T 下界 at the upper and lower boundaries of the thermocline. By interpolation and simulation, the water pressure gradient tensors and the flow velocity gradient tensors

[0092] at the upper and lower boundaries of the thermocline are obtained.

[0093]

[0094] Substitute the above values into the momentum equation:

[0095]

[0096] Substitute the above values into the energy equation: Substitute the above values into the momentum equation and the energy equation at the lower boundary of the thermocline, and solve for And respectively identify the velocity and direction of the axial offset of the upper and lower boundaries of the thermocline, that is, reflect the rate of thermocline thickening.

[0097] By collecting the relationship curve clusters and under different high-temperature water temperatures T-high temperature water and low-temperature water temperatures T-low temperature water conditions and integrating and analyzing them, the ideal high-temperature water temperature T-high temperature water interval and low-temperature water temperature T-low temperature water interval of the water storage tank 1 with this aspect ratio and size can be obtained, and further the ideal tank top inlet flow rate interval and ideal tank bottom outlet flow rate interval can be obtained. In this way, the optimal operating conditions corresponding to the water storage tank 1 with this aspect ratio and size can be quickly obtained. Operating in mode 2 (water storage tank cooling mode) with this optimal operating condition can greatly save energy consumption and is beneficial to environmental protection.

[0098] Each fan coil unit of the temperature control system of the present invention is equipped with an outlet air temperature and humidity sensor, a return air temperature and humidity sensor, an energy meter and a thermostat, and can sense the operating conditions of each fan coil unit in real time. For fan coil units with different coil rows (two-row tubes, three-row tubes or four-row tubes), or fan coil units with different valve types (ball valves or on-off valves), the above sensors can record the operating data of each fan coil unit in real time, facilitating comparison between fan coil units with different configurations and discovering differences.

[0099] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any brief modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A central air conditioning temperature control system, characterized in that: It includes a water storage tank, a chiller and several terminal coils. A low-temperature water filling pipeline and a high-temperature water return pipeline are connected between the water storage tank and the chiller. The low-temperature water filling pipeline is provided with two low-temperature water filling stop valves and a low-temperature water filling pump. The high-temperature water return pipeline is provided with two high-temperature water return stop valves. The low-temperature water filling pipeline section between the two low-temperature water filling stop valves is connected with a low-temperature water distribution trunk. The water inlet end of the low-temperature water distribution trunk is connected with a low-temperature water distribution main valve. The low-temperature water distribution trunk is connected to each terminal coil through a low-temperature water distribution branch. Each low-temperature water distribution branch is connected with a flow control valve. The high-temperature water return pipeline section between the two high-temperature water return stop valves is connected with a high-temperature water confluence trunk. The water outlet end of the high-temperature water confluence trunk is connected with a high-temperature water distribution main valve. The high-temperature water confluence trunk is connected to each terminal coil through a high-temperature water distribution branch. The high-temperature water distribution branch is connected with a branch water pump.

2. The central air-conditioning temperature control system according to claim 1 is characterized in that: The low-temperature water filling pipeline is equipped with a water thermometer.

3. The central air-conditioning temperature control system according to claim 2 is characterized in that: The high-temperature water return pipe is equipped with a water thermometer.

4. The central air-conditioning temperature control system according to claim 3 is characterized in that: The low-temperature water filling pipeline is equipped with a flow meter.

5. The central air-conditioning temperature control system according to claim 4 is characterized in that: The high-temperature water return pipeline is equipped with a flow meter.

6. The central air-conditioning temperature control system according to claim 5 is characterized in that: Each low-temperature water distribution branch is equipped with a water thermometer.

7. The central air-conditioning temperature control system according to claim 6 is characterized in that: Each high-temperature water distribution branch is equipped with a water thermometer.

8. The control method applied to the control system according to claim 7, characterized in that: The following steps are involved: Sensor mounting frame arrangement steps: multiple layers of concentric ring mounting frames are suspended in the water storage tank, each layer of the concentric ring mounting frames is evenly arranged with multiple flow rate sensors, water pressure sensors and water temperature sensors, and each layer of the concentric ring mounting frames is arranged vertically at intervals, so that the distance between the highest concentric ring mounting frame and the lowest concentric ring mounting frame is greater than the maximum value of the thickness of the inclined temperature layer corresponding to the water storage tank; Low-temperature water filling steps: The chiller inputs low-temperature water through the bottom of the water storage tank until the entire water storage tank is filled; The height position positioning step of the inclined temperature layer: the low-temperature water stored in the water storage tank is pumped to each terminal coil, and the low-temperature water becomes high-temperature water after passing through the terminal coil, and flows back to the top of the water storage tank through the high-temperature water return pipe, and the low-temperature water is discharged at the bottom of the water storage tank. At the same time, in the process of receiving high-temperature water at the top of the water storage tank, the water body in the water storage tank gradually forms an inclined temperature layer, and the cage is slowly suspended vertically from top to bottom. The water temperature sensors of the concentric ring mounting frames of each layer sense the water temperature at each height position in real time until two temperature mutations are sensed: the temperature mutation at the lower side is determined as the lower boundary of the inclined temperature layer, and the temperature mutation at the upper side is determined as the upper boundary of the inclined temperature layer; Numerical sensing and simulation steps: The velocity sensor senses the velocity of each layer near the upper and lower boundaries of the thermocline layer in real time, and the velocity gradient tensor at the upper and lower boundaries of the thermocline layer is obtained by Kriging interpolation and radial basis function simulation. And measure the flow velocity at the upper and lower boundaries of the thermocline layer; The water pressure sensor senses the water pressure of each layer near the upper and lower boundaries of the thermocline layer in real time, and the water pressure gradient tensor at the upper and lower boundaries of the thermocline layer is obtained by Kriging interpolation and radial basis function simulation. The water pressure p at the upper and lower boundaries of the thermocline layer is measured. 上界 、p 下界 The water temperature sensor measures the water temperature T at the upper and lower boundaries of the thermocline layer in real time. 上界 , T 下界 ; Steps for combining equations: Substitute the upper boundary of the thermocline u 上界 , and the lower boundary of the thermocline u 下界 , Substitute them into the momentum equation as follows: By T 上界 The internal energy E at the upper boundary of the thermocline layer is calculated 上界 , through T 下界 The internal energy E at the lower boundary of the thermocline is calculated 下界 , then, the E at the upper boundary of the thermocline 上界 、u 上界 、p 上界 and E at the lower boundary of the thermocline 下界 、u 下界 、p 下界 Substitute them into the following energy equation: Combining the momentum equation and energy equation at the upper boundary of the thermocline, we can solve the temperature gradient at the upper boundary of the thermocline. Combining the momentum equation and energy equation at the lower boundary of the thermocline, we can solve the temperature gradient at the lower boundary of the thermocline. Steps for analyzing the migration law of the inclined temperature layer: When the water storage tank provides cooling for each terminal coil, the upper and lower boundaries of the inclined temperature layer will gradually shift. Under any high-temperature water temperature T-high-temperature water and any low-temperature water temperature T-low-temperature water, the water temperature sensors of each layer of concentric ring mounting frame are used to track and locate the height position to which the upper boundary of the inclined temperature layer shifts in real time, and the real-time temperature gradient of the upper boundary of the inclined temperature layer under the water temperature condition is calculated. Obtain the real-time temperature gradient of the upper boundary of the thermocline under the water temperature condition Real-time flow rate of water from the tank bottom F 罐底出水 And the real-time flow rate of water entering the tank top F 罐顶进水 The relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions are collected to obtain the curve cluster of the upper boundary offset law of the thermocline layer Under any high-temperature water temperature T-high-temperature water and any low-temperature water temperature T-low-temperature water, the water temperature sensors of each layer of concentric ring mounting frame are used to track and locate the position to which the lower boundary of the thermocline layer is offset in real time, and the real-time temperature gradient of the lower boundary of the thermocline layer under the water temperature condition is calculated. Obtain the real-time temperature gradient of the lower boundary of the thermocline under the water temperature condition Real-time flow rate of water from the tank bottom F 罐底出水 And the real-time flow rate of water entering the tank top F 罐顶进水 The relationship curves between the high-temperature water temperature T-high-temperature water and the low-temperature water temperature T-low-temperature water are combined to obtain the cluster of regular curves of the lower boundary of the thermocline layer. Integration and And perform data analysis to obtain and The high-temperature water temperature T-high-temperature water interval and the low-temperature water temperature T-low-temperature water interval of the water storage tank corresponding to the smaller interval are called the ideal high-temperature water temperature interval and the ideal low-temperature water temperature interval. The ideal high-temperature water temperature interval corresponds to an ideal tank top water inlet flow interval, and the ideal low-temperature water temperature interval corresponds to an ideal tank bottom water outlet flow interval. Branch flow and terminal coil cooling capacity distribution steps: Establish a coordinated adjustment mechanism for the cooling capacity of each terminal coil: when the water outlet temperature at the bottom of the tank is in the ideal low-temperature water temperature range, and the water inlet temperature at the top of the tank is in the ideal high-temperature water temperature range, the cooling capacity of each terminal coil 3 meets the demand. On this basis, establish a coordinated adjustment mechanism for the flow of each inlet branch and each outlet branch: make the total inflow flow of low-temperature water of each inlet branch within the ideal tank bottom water outlet flow range, and make the total outflow flow of high-temperature water of each outlet branch within the ideal tank top water inlet flow range.

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