A central air conditioning temperature control system and control method

Abstract

This invention relates to a central air conditioning temperature control system, comprising a water storage tank, a chiller unit, and several terminal coils. A low-temperature water filling pipeline and a high-temperature water return pipeline connect the water storage tank and the chiller unit. The low-temperature water filling pipeline is equipped with two low-temperature water filling shut-off valves and a low-temperature water filling pump. The high-temperature water return pipeline is equipped with two high-temperature water return shut-off valves. The section of the low-temperature water filling pipeline between the two low-temperature water filling shut-off valves is connected to a low-temperature water distribution main line. The inlet end of the low-temperature water distribution main line is connected to a low-temperature water distribution master valve. The low-temperature water distribution main line is connected to each terminal coil via low-temperature water distribution branch lines, and each low-temperature water distribution branch line is connected to a flow control valve. This invention can quickly obtain the optimal combination of operating parameters for the system, thereby improving the energy efficiency of the central air conditioning temperature control system and contributing to energy conservation and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of central air conditioning temperature control technology, specifically to a central air conditioning temperature control system and control method. Background Technology

[0002] To achieve peak shaving and valley filling of electricity consumption and realize green energy conservation, the central air conditioning temperature control system adopts a "low-temperature water filling mode" at night to fill the storage tank with chilled water. During the day, the central air conditioning temperature control system adopts a "storage tank cooling mode" to supply chilled water to each terminal coil.

[0003] When operating in "water tank cooling mode," a "thermotropic layer" gradually forms inside the water tank. If this layer thickens, it increases heat loss and reduces the tank's energy storage efficiency. Typically, the thermotropic layer thickness should be kept below 1 meter to ensure high energy storage efficiency. The temperature of the stored low-temperature water, the temperature of the high-temperature water, the flow rate of the low-temperature water, and the flow rate of the high-temperature water all influence the rate of thermotropic layer thickening. Furthermore, the tank's own dimensions, such as the height-to-diameter ratio, also affect the rate of thermotropic layer thickening.

[0004] After replacing the water tank with a new one of different size (or height-to-diameter ratio), the rate of thickening of the thermocline will change. In order to make the new water tank reach the minimum rate of thickening of the thermocline 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. Only by trying the optimal combination of the above parameters can the new water tank reach the minimum rate of thickening of the thermocline again. The above trial process is time-consuming, inefficient, and may not be able to find the optimal combination of parameters. Summary of the Invention

[0005] The purpose of this invention is to provide a central air conditioning temperature control system and control method, which can quickly obtain the optimal combination of operating parameters of the system to improve the energy efficiency of the central air conditioning temperature control system and is conducive to energy conservation and environmental protection.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A central air conditioning temperature control system includes a water storage tank, a chiller unit, 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 unit. The low-temperature water filling pipeline is equipped with two low-temperature water filling shut-off valves and a low-temperature water filling pump. The high-temperature water return pipeline is equipped with two high-temperature water return shut-off valves. A low-temperature water distribution main line is connected between the two low-temperature water filling shut-off valves. A low-temperature water distribution master valve is connected to the inlet end of the low-temperature water distribution main line. The low-temperature water distribution main line is connected to each terminal coil via low-temperature water distribution branch lines. Each low-temperature water distribution branch line is connected to a flow control valve. A high-temperature water return pipeline is connected between the two high-temperature water return shut-off valves. A high-temperature water manifold is connected to the outlet end of the high-temperature water manifold, and the high-temperature water manifold is connected to each terminal coil via high-temperature water distribution branch lines. A branch water pump is connected to each high-temperature water distribution branch line.

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

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

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

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

[0012] Specifically, each low-temperature water distribution branch is equipped with a water thermometer.

[0013] Specifically, each high-temperature water distribution branch is equipped with a water thermometer.

[0014] The control method applied to the control system is characterized by comprising the following steps:

[0015] Sensor mounting rack arrangement steps: The multi-layer concentric ring mounting rack is suspended in the water storage tank. Each layer of the concentric ring mounting rack is evenly arranged with multiple flow rate sensors, water pressure sensors and water temperature sensors. The concentric ring mounting racks are arranged vertically at intervals, so that the distance between the highest concentric ring mounting rack and the lowest concentric ring mounting rack is greater than the maximum thickness of the corresponding inclined temperature layer of the water storage tank.

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

[0017] Steps for locating the height of the inclined thermosphere: The low-temperature water stored in the water tank is pumped to each terminal coil. After flowing through the terminal coil, the low-temperature water becomes high-temperature water and flows back to the top of the water tank through the high-temperature water return pipe. The low-temperature water is discharged at the bottom of the water tank. At the same time, as the top of the water tank receives the high-temperature water, the water in the water tank gradually forms an inclined thermosphere. The cage is slowly lowered vertically from top to bottom. The water temperature sensors of each layer of the concentric ring mounting frame sense the water temperature at each height position in real time until two temperature change points are sensed: the temperature change point on the lower side is determined to be the lower boundary of the inclined thermosphere, and the temperature change point on the upper side is determined to be the upper boundary of the inclined thermosphere.

[0018] Numerical sensing and simulation steps: The velocity sensor senses the flow velocity in each layer near the upper and lower boundaries of the thermocline in real time. Kriging interpolation and radial basis functions are used to simulate and obtain the velocity gradient tensor at the upper and lower boundaries of the thermocline. The flow velocity u at the upper and lower boundaries of the thermocline was measured. 上界 u 下界 ;

[0019] A water pressure sensor detects the water pressure in layers near the upper and lower boundaries of the thermocline in real time. Kriging interpolation and radial basis functions are used to simulate and derive the water pressure gradient tensors at the upper and lower boundaries of the thermocline. The water pressure p at the upper and lower boundaries of the thermocline was measured. 上界 p 下界 The water temperature sensor measures the water temperature T at the upper and lower boundaries of the thermocline in real time. 上界 T 下界 ;

[0020] Steps for solving the equations simultaneously: [The equations are then defined as follows:] [The equations are then defined as follows u 上界 , and the lower boundary of the thermocline u 下界 , Substituting into the following momentum equations:

[0021]

[0022] Through T 上界 The internal energy E at the upper boundary of the thermosphere is calculated. 上界 Through T 下界 The internal energy E at the lower boundary of the thermocline was calculated. 下界 Subsequently, the E at the upper boundary of the thermocline 上界 u 上界 p 上界 and the lower boundary of the thermocline E 下界 u 下界 p 下界 Substitute them into the following energy equations:

[0023]

[0024] By simultaneously solving the momentum and energy equations for the upper boundary of the thermocline, the temperature gradient at the upper boundary of the thermocline can be obtained. By simultaneously solving the momentum and energy equations for the lower boundary of the thermocline, the temperature gradient at the lower boundary of the thermocline can be obtained.

[0025] Steps for analyzing the migration pattern of the thermocline: During the cooling 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 Thigh-temperature water and any low-temperature water temperature Tlow-temperature water, the water temperature sensors of each concentric ring mounting frame are used to track and locate the height position of the shifted upper boundary of the thermocline in real time, and calculate the real-time temperature gradient of the upper boundary of the thermocline under the water temperature condition. Obtain the real-time temperature gradient of the upper boundary of the thermocline under this water temperature condition. Real-time flow rate F of water emanating from the bottom of the tank 罐底出水 and the real-time flow rate F of the water entering from the top of the tank 罐顶进水 The relationship curves are compiled by combining the relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions to obtain a cluster of curves showing the upper boundary shift of the thermocline.

[0026] Under any given high-temperature water temperature Thigh-temperature water and any given low-temperature water temperature Tlow-temperature water, the water temperature sensors on each concentric ring mounting frame track and locate the position of the lower boundary of the thermocline layer in real time, and calculate the real-time temperature gradient of the lower boundary of the thermocline layer under that water temperature condition. Obtain the real-time temperature gradient of the lower boundary of the thermocline under this water temperature condition. Real-time flow rate F of water emanating from the bottom of the tank 罐底出水 and the real-time flow rate F of the water entering from the top of the tank 罐顶进水 The relationship curves, which are obtained by combining the relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions, yield a cluster of curves showing the migration pattern of the lower boundary of the thermocline.

[0027] Integration and And conduct data analysis to obtain and The high-temperature water temperature T-high-temperature water range and the low-temperature water temperature T-low-temperature water range corresponding to the smaller range are called the ideal high-temperature water temperature range and the ideal low-temperature water temperature range. The ideal high-temperature water temperature range corresponds to an ideal tank top inlet flow range, and the ideal low-temperature water temperature range corresponds to an ideal tank bottom outlet flow range.

[0028] Branch flow and terminal coil cooling capacity allocation steps: Establish a coordinated adjustment mechanism for the cooling capacity of each terminal coil: When the water temperature at the bottom of the tank is within the ideal low-temperature water temperature range and the water temperature at the top of the tank is within the ideal high-temperature water temperature range, the cooling capacity of each terminal coil 3 meets the requirements. Based on this, establish a coordinated adjustment mechanism for the flow of each inlet branch and each outlet branch: Ensure that the total flow of low-temperature water into each inlet branch is within the ideal bottom outlet flow range, and ensure that the total flow of high-temperature water out of each outlet branch is within the ideal top inlet flow range.

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

[0030] For different height-to-diameter ratios and sizes of water storage tank 1, cages 7 and concentric ring mounting frames 6 of corresponding sizes are designed so that the diameter of the outermost ring corresponds to the inner diameter of water storage tank 1.

[0031] Multiple flow rate sensors, water pressure sensors, and water temperature sensors are evenly arranged on the outer wall of the concentric rings, so that the diameter of each ring of the concentric ring mounting frame 6 in the same layer increases in an appropriate size, thereby ensuring that the above sensors are evenly and densely distributed in the same layer.

[0032] The assembly consisting of the cage body 7 and the multi-layer concentric ring mounting frame 6 is hoisted into the inner cavity of the water storage tank 1. First, the cage body 7 is hoisted to the upper part of the inner cavity of the water storage tank 1 (e.g., Figure 1 As shown, the inclined temperature layer is generally formed first on the upper part, and the maximum thickness of the inclined temperature layer is generally 1 meter, that is, the distance between the highest concentric ring mounting frame 6 and the lowest concentric ring mounting frame 6 is greater than 1 meter.

[0033] Then, the water storage tank 1 operates in the above-mentioned mode 2 (water storage tank cooling mode). During operation, a temperature gradient layer is generated between the low-temperature water and the high-temperature water in the water storage tank 1. The temperature gradient layer has a certain thickness. The boundary between the temperature gradient layer and the high-temperature water is the upper boundary of the temperature gradient layer, and the boundary between the temperature gradient layer and the low-temperature water is the lower boundary of the temperature gradient layer.

[0034] The dense array of flow velocity sensors, water pressure sensors, and water temperature sensors near the corresponding height positions can measure the flow velocity u at the upper and lower boundaries of the thermocline. 上界 u 下界 The water pressure p at the upper and lower boundaries of the thermocline 上界 p 下界 And the water temperature T at the upper and lower boundaries of the thermocline. 上界 T 下界 The water pressure gradient tensors at the upper and lower boundaries of the thermocline were obtained through interpolation and simulation. and the velocity gradient tensor at the upper and lower boundaries of the thermocline.

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

[0036]

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

[0038]

[0039] By combining the momentum and energy equations for the upper boundary of the thermocline, we can obtain... By combining the momentum and energy equations for the lower boundary of the thermocline, we obtain... and The velocity and direction of the axial shift of the upper and lower boundaries of the thermocline are respectively indicated, which reflects the rate of thermocline thickening.

[0040] By compiling a cluster of relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions and By integrating and analyzing these data, we can obtain the ideal high-temperature water temperature range T-high-temperature water range and the ideal low-temperature water temperature range T-low-temperature water range for the water storage tank 1 with its height-to-diameter ratio and size. Furthermore, we can obtain the ideal inlet flow range at the top of the tank and the ideal outlet flow range at the bottom of the tank. In this way, we can quickly determine the optimal operating conditions for the water storage tank 1 with its height-to-diameter ratio and size. Operating the second mode (water storage tank cooling mode) under these optimal operating conditions can greatly save energy consumption and is beneficial to green environmental protection. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a system diagram of a central air conditioning temperature control system.

[0043] Figure 2 It is a combination of a cage and a multi-layered concentric ring-shaped mounting frame;

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

[0045] Figure 4 It is a cage.

[0046] In the picture:

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

[0048] 3. Terminal coils;

[0049] 4. Water thermometer;

[0050] 5. Flow meter;

[0051] 6. Concentric ring mounting bracket;

[0052] 7. Cage. Detailed Implementation

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0054] See Figure 1 A central air conditioning temperature control system includes a water storage tank 1, a chiller unit 2, and several terminal coils 3. A low-temperature water filling pipeline 21 and a high-temperature water return pipeline 22 connect the water storage tank 1 and the chiller unit 2. The low-temperature water filling pipeline 21 is equipped with two low-temperature water filling shut-off valves 211 and a low-temperature water filling pump 212. The high-temperature water return pipeline 22 is equipped with two high-temperature water return shut-off valves 221.

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

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

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

[0058] Specifically, a water thermometer 4 is installed in the high-temperature water return pipe 22.

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

[0060] Specifically, a flow meter 5 is installed in the high-temperature water return pipe 22.

[0061] Specifically, each low-temperature water distribution branch 24 is equipped with a water thermometer 4.

[0062] Specifically, each high-temperature water distribution branch 26 is equipped with a water thermometer 4.

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

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

[0065] When electricity prices are lower at night, chiller unit 2 is used for cooling and storage of cold water. Specifically, the low-temperature water distribution main valve 231 and the high-temperature water distribution main valve 251 are closed, while the two low-temperature water filling shut-off valves 211 and the two high-temperature water return shut-off valves 221 are opened. The low-temperature water produced by chiller unit 2 is then transported to the bottom of water storage tank 1 through the low-temperature water filling pipeline 21 until the water storage tank 1 is full of cold water.

[0066] Mode 2: Cooling mode using water storage tanks

[0067] When daytime electricity prices are high, chiller unit 2 is shut down, and cooling is supplied by the water storage tank. Specifically, the low-temperature water filling shut-off valve 211 on the right side of the low-temperature water filling pipeline 21 is closed, and the high-temperature water return shut-off valve 221 on the right side of the high-temperature water return pipeline 22 is closed, thus shutting down chiller unit 2. Then, both the low-temperature water distribution main valve 231 and the high-temperature water distribution main valve 251 are opened. At this time, the low-temperature water at the bottom of the water storage tank 1 enters the low-temperature water distribution trunk line 23 through the low-temperature water filling pipeline 21, then enters each terminal coil 3, flows into the high-temperature water collection trunk line 25, then enters the high-temperature water return pipeline 22, and finally flows into the top of the water storage tank 1.

[0068] During operation in Mode 2, the liquid in storage tank 1 stratifies into layers: a lower layer of low-temperature water and a top layer of high-temperature water, forming a thermocline between the two layers. While ensuring the normal operation of terminal coil 3, selecting appropriate flow rate and cooling capacity for terminal coil 3 can help delay the thickening of the thermocline, thereby improving the cooling efficiency of storage tank 1. The control method is as follows:

[0069] Combination Figures 2 to 4 The control method applied to the control system includes the following steps:

[0070] Sensor mounting bracket arrangement steps: Install the multi-layer concentric ring mounting bracket 6 (the multi-layer concentric ring mounting bracket 6 is installed on the cage body 7 to form a combined body, such as...) Figure 2As shown, the concentric ring-shaped mounting frames 6 are suspended inside the water storage tank 1. Multiple flow rate sensors, water pressure sensors, and water temperature sensors are evenly arranged on the rings of each layer. The concentric ring-shaped mounting frames 6 are arranged vertically at intervals, such that the distance between the highest and lowest concentric ring-shaped mounting frame 6 is greater than the maximum thickness of the inclined temperature layer corresponding to the water storage tank 1. For the water storage tank, the maximum thickness of the inclined temperature layer is assumed to be 1m.

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

[0072] Steps for locating the height of the thermocline: The low-temperature water stored in the storage tank 1 is pumped to each terminal coil 3. After flowing through the terminal coil 3, the low-temperature water becomes high-temperature water and flows back to the top of the storage tank 1 through the high-temperature water return pipe 22. During the process of discharging low-temperature water at the bottom of the storage tank 1 and receiving high-temperature water at the top of the storage tank 1, a thermocline gradually forms in the water inside the storage tank 1. The cage 7 is slowly lowered vertically from top to bottom. The water temperature sensors of each layer of the concentric ring mounting frame 6 sense the water temperature at each height position in real time until two temperature abrupt changes are detected: the temperature abrupt change on the lower side is determined to be the lower boundary of the thermocline, and the temperature abrupt change on the upper side is determined to be the upper boundary of the thermocline.

[0073] Numerical sensing and simulation steps: The velocity sensor senses the flow velocity in each layer near the upper and lower boundaries of the thermocline in real time. Kriging interpolation and radial basis functions are used to simulate and obtain the velocity gradient tensor at the upper and lower boundaries of the thermocline. The flow velocity u at the upper and lower boundaries of the thermocline was measured. 上界 u 下界 ;

[0074] A water pressure sensor detects the water pressure in layers near the upper and lower boundaries of the thermocline in real time. Kriging interpolation and radial basis functions are used to simulate and derive the water pressure gradient tensors at the upper and lower boundaries of the thermocline. The water pressure p at the upper and lower boundaries of the thermocline was 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 in real time. 上界 T 下界 ;

[0076] Steps for solving the equations simultaneously: [The equations are then defined as follows:] [The equations are then defined as follows u 上界 , and the lower boundary of the thermocline u 下界 , Substituting into the following momentum equations:

[0077]

[0078] Through T 上界 The internal energy E at the upper boundary of the thermosphere is calculated. 上界 Through T 下界 The internal energy E at the lower boundary of the thermocline was calculated. 下界 Subsequently, the E at the upper boundary of the thermocline 上界 u 上界 p 上界 and the lower boundary of the thermocline E 下界 u 下界 p 下界 Substitute them into the following energy equations:

[0079]

[0080] By simultaneously solving the momentum and energy equations for the upper boundary of the thermocline, the temperature gradient at the upper boundary of the thermocline can be obtained. By simultaneously solving the momentum and energy equations for the lower boundary of the thermocline, the temperature gradient at the lower boundary of the thermocline can be obtained.

[0081] Steps for analyzing the migration pattern of the thermocline: During the cooling 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, the water temperature sensors of each concentric ring mounting bracket 6 track and locate the height position of the shifted upper boundary of the thermocline in real time, and calculate the real-time temperature gradient of the upper boundary of the thermocline under the water temperature condition. Obtain the real-time temperature gradient of the upper boundary of the thermocline under this water temperature condition. Real-time flow rate F of water emanating from the bottom of the tank 罐底出水 and the real-time flow rate F of the water entering from the top of the tank 罐底进水 The relationship curves are compiled by combining the relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions to obtain a cluster of curves showing the upper boundary shift of the thermocline.

[0082] 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 concentric ring mounting frame 6 track and locate the height position of the lower boundary of the thermocline layer in real time, and calculate the real-time temperature gradient of the lower boundary of the thermocline layer under the given water temperature conditions. Obtain the real-time temperature gradient of the lower boundary of the thermocline under this water temperature condition. Real-time flow rate F of water emanating from the bottom of the tank 罐底出水 and the real-time flow rate F of the water entering from the top of the tank 罐顶进水The relationship curves are compiled by combining the relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions to obtain a cluster of curves showing the lower boundary shift of the thermocline.

[0083] Integration and And conduct data analysis to obtain and The high-temperature water temperature T-high-temperature water range and the low-temperature water temperature T-low-temperature water range corresponding to the water storage tank 1 when it is in a smaller range are called the ideal high-temperature water temperature range and the ideal low-temperature water temperature range. The ideal high-temperature water temperature range corresponds to an ideal tank top inlet flow range, and the ideal low-temperature water temperature range corresponds to an ideal tank bottom outlet flow range.

[0084] Branch flow rate and cooling capacity distribution steps for terminal coil 3:

[0085] Establish a coordinated cooling capacity adjustment mechanism for each terminal coil 3: This ensures that when the water temperature at the bottom of the tank is within the ideal low-temperature water temperature range and the water temperature at the top of the tank is within the ideal high-temperature water temperature range, the cooling capacity of each terminal coil 3 meets the demand. Based on this, establish a coordinated flow rate adjustment mechanism for each inlet branch and each outlet branch: This ensures that the total inflow of low-temperature water into each inlet branch is within the ideal bottom outlet flow rate range, and that the total outflow of high-temperature water from each outlet branch is within the ideal top inlet flow rate range.

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

[0087] For different height-to-diameter ratios and sizes of water storage tank 1, cages 7 and concentric ring mounting frames 6 of corresponding sizes are designed so that the diameter of the outermost ring corresponds to the inner diameter of water storage tank 1.

[0088] Multiple flow rate sensors, water pressure sensors, and water temperature sensors are evenly arranged on the outer wall of the concentric rings, so that the diameter of each ring of the concentric ring mounting frame 6 in the same layer increases in an appropriate size, thereby ensuring that the above sensors are evenly and densely distributed in the same layer.

[0089] The assembly consisting of the cage body 7 and the multi-layer concentric ring mounting frame 6 is hoisted into the inner cavity of the water storage tank 1. First, the cage body 7 is hoisted to the upper part of the inner cavity of the water storage tank 1 (e.g., Figure 1 As shown, the inclined temperature layer is generally formed first on the upper part, and the maximum thickness of the inclined temperature layer is generally 1 meter, that is, the distance between the highest concentric ring mounting frame 6 and the lowest concentric ring 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 operation, a temperature gradient layer is generated between the low-temperature water and the high-temperature water in the water storage tank 1. The temperature gradient layer has a certain thickness. The boundary between the temperature gradient layer and the high-temperature water is the upper boundary of the temperature gradient layer, and the boundary between the temperature gradient layer and the low-temperature water is the lower boundary of the temperature gradient layer.

[0091] The dense array of flow velocity sensors, water pressure sensors, and water temperature sensors near the corresponding height positions can measure the flow velocity u at the upper and lower boundaries of the thermocline. 上界 u 下界 The water pressure p at the upper and lower boundaries of the thermocline 上界 p 下界 And the water temperature T at the upper and lower boundaries of the thermocline. 上界 T 下界 The water pressure gradient tensors at the upper and lower boundaries of the thermocline were obtained through interpolation and simulation. and the velocity gradient tensor at the upper and lower boundaries of the thermocline.

[0092] Substituting the above values ​​into the momentum equation:

[0093]

[0094] Substituting the above values ​​into the energy equation:

[0095]

[0096] By combining the momentum and energy equations for the upper boundary of the thermocline, we can obtain... By combining the momentum and energy equations for the lower boundary of the thermocline, we obtain... and The velocity and direction of the axial shift of the upper and lower boundaries of the thermocline are respectively indicated, which reflects the rate of thermocline thickening.

[0097] By compiling a cluster of relationship curves under different high-temperature water temperature T-high-temperature water and low-temperature water temperature T-low-temperature water conditions and By integrating and analyzing these data, we can obtain the ideal high-temperature water temperature range T-high-temperature water range and the ideal low-temperature water temperature range T-low-temperature water range for the water storage tank 1 with its height-to-diameter ratio and size. Furthermore, we can obtain the ideal inlet flow range at the top of the tank and the ideal outlet flow range at the bottom of the tank. In this way, we can quickly determine the optimal operating conditions for the water storage tank 1 with its height-to-diameter ratio and size. Operating the second mode (water storage tank cooling mode) under these optimal operating conditions can greatly save energy consumption and is beneficial to green environmental protection.

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

[0099] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1.A control method of a central air conditioning temperature control system, the control system comprising a water storage tank, a water chiller unit and a plurality of terminal coils, a low-temperature water charging pipeline and a high-temperature water return pipeline being connected between the water storage tank and the water chiller unit, the low-temperature water charging pipeline being provided with two low-temperature water charging stop valves and a low-temperature water charging pump, the high-temperature water return pipeline being provided with two high-temperature water return stop valves, a low-temperature water distribution main pipeline being connected to a section of the low-temperature water charging pipeline between the two low-temperature water charging stop valves, a low-temperature water distribution total valve being connected to an inlet end of the low-temperature water distribution main pipeline, the low-temperature water distribution main pipeline being connected to each terminal coil through a low-temperature water distribution branch pipeline, each low-temperature water distribution branch pipeline being provided with a flow control valve, a high-temperature water distribution main pipeline being connected to a section of the high-temperature water return pipeline between the two high-temperature water return stop valves, a high-temperature water distribution total valve being connected to an outlet end of the high-temperature water distribution main pipeline, the high-temperature water distribution main pipeline being connected to each terminal coil through a high-temperature water distribution branch pipeline, each high-temperature water distribution branch pipeline being provided with a branch water pump, a water temperature meter being provided in the low-temperature water charging pipeline, a water temperature meter being provided in the high-temperature water return pipeline, a flow meter being provided in the low-temperature water charging pipeline, a flow meter being provided in the high-temperature water return pipeline, a water temperature meter being provided in each low-temperature water distribution branch pipeline, a water temperature meter being provided in each high-temperature water distribution branch pipeline, the control method comprising the following steps: a sensor mounting rack arrangement step: a plurality of concentric ring-shaped mounting racks are hung in the water storage tank, each concentric ring-shaped mounting rack being uniformly provided with a plurality of flow rate sensors, water pressure sensors and water temperature sensors, the concentric ring-shaped mounting racks being vertically spaced apart, so that the spacing between the highest concentric ring-shaped mounting rack and the lowest concentric ring-shaped mounting rack is greater than the maximum value of the thermocline thickness of the water storage tank; a low-temperature water charging step: the water chiller unit charges low-temperature water into the water storage tank through the bottom of the water storage tank until the entire water storage tank is filled; a thermocline height position positioning step: the low-temperature water stored in the water storage tank is pumped to each terminal coil, the low-temperature water becomes high-temperature water after flowing through the terminal coil, and the high-temperature water returns to the top of the water storage tank through the high-temperature water return pipeline, the low-temperature water is discharged at the bottom of the water storage tank, and at the same time, the water body in the water storage tank gradually forms a thermocline during the process of receiving the high-temperature water at the top of the water storage tank, the cage is slowly hung from top to bottom along the vertical direction, the water temperature sensors of each concentric ring-shaped mounting rack sense the water temperature at each height position in real time until two temperature mutation positions are sensed: the lower temperature mutation position is determined as the lower boundary of the thermocline, and the upper temperature mutation position is determined as the upper boundary of the thermocline; a branch flow rate and terminal coil cooling capacity distribution step: a cooling capacity cooperative adjustment mechanism of each terminal coil is established: when the tank bottom outlet water temperature is in an ideal low-temperature water temperature range and the top inlet water temperature is in an ideal high-temperature water temperature range, the cooling capacity of each terminal coil meets the demand, on this basis, a flow rate cooperative adjustment mechanism of each inlet branch and outlet branch is established: the total flow rate of the low-temperature water flowing into each inlet branch is in an ideal tank bottom outlet water flow rate range, and the total flow rate of the high-temperature water flowing out of each outlet branch is in an ideal tank top inlet water flow rate range. characterized in that ​ ​ ​ ​ Numerical sensing, simulation step: the flow rate sensor senses the flow rate of each layer near the upper boundary of the thermocline and the lower boundary of the thermocline in real time, and the flow rate gradient tensor at the upper boundary of the thermocline and the lower boundary of the thermocline is simulated by using the Kriging interpolation method and using the radial basis function 、 , and the flow rate at the upper boundary of the thermocline and the lower boundary of the thermocline is measured 、 ; The water pressure sensor senses the water pressure of each layer near the upper boundary of the thermocline and the lower boundary of the thermocline in real time, obtains the water pressure gradient tensor at the upper boundary of the thermocline and the lower boundary of the thermocline by using Kriging interpolation method and radial basis function simulation 、 , and measures the water pressure at the upper boundary of the thermocline and the lower boundary of the thermocline 、 The water temperature sensor measures the water temperature at the upper boundary of the thermocline and the lower boundary of the thermocline in real time , ; Equation system step: Substitute the upper boundary of the thermocline , , and the lower boundary of the thermocline , , into the momentum equation respectively: By The internal energy at the upper boundary of the thermocline is calculated as By The internal energy at the lower boundary of the thermocline is calculated as Then, the internal energy at the upper boundary of the thermocline is calculated as , , and the internal energy at the lower boundary of the thermocline is calculated as , , respectively by substituting the above into the following energy equation: Solving the momentum equation and the energy equation of the upper boundary of the thermocline, the temperature gradient at the upper boundary of the thermocline is obtained Solving the momentum equation and the energy equation of the lower boundary of the thermocline, the temperature gradient at the lower boundary of the thermocline is obtained ; The step of analyzing the migration law of the thermocline is as follows: in the process of supplying cooling for each terminal coil by the water storage tank, the upper boundary of the thermocline and the lower boundary of the thermocline will gradually shift, under the condition of any high-temperature water temperature and any low-temperature water temperature , the water temperature sensor of each layer concentric ring mounting frame is used to track and locate the height position to which the upper boundary of the thermocline shifts in real time, and the real-time temperature gradient of the upper boundary of the thermocline under the water temperature condition is calculated , the real-time temperature gradient of the upper boundary of the thermocline under the water temperature condition is obtained , and the relationship curve between the real-time temperature gradient of the upper boundary of the thermocline and the real-time flow of water out of the tank bottom and the real-time flow of water into the tank top is obtained, the relationship curves under different high-temperature water temperatures and low-temperature water temperatures are collected, and a curve cluster of the migration law of the upper boundary of the thermocline is obtained . Under any high temperature water temperature and any low temperature water temperature , the water temperature sensor through each layer concentric ring mounting bracket real-time tracking positioning the position where the lower boundary of the thermocline deviates to, and calculating the real-time temperature gradient of the lower boundary of the thermocline under the water temperature condition , obtaining the real-time temperature gradient of the lower boundary of the thermocline under the water temperature condition , the relationship curve between the real-time flow of the water out of the tank bottom and the real-time flow of the water into the tank top , collecting the relationship curves under different high temperature water temperature and low temperature water temperature , obtaining the curve cluster of the deviation rule of the lower boundary of the thermocline , integrate with and data analysis, get with Corresponding to the water tank high temperature water temperature when in a smaller interval range Interval and low temperature water temperature Interval, called ideal high temperature water temperature interval and ideal low temperature water temperature interval, ideal high temperature water temperature interval corresponds to an ideal tank top water inflow interval, and ideal low temperature water temperature interval corresponds to an ideal tank bottom water outflow interval; ​

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