Online temperature control method and system for differentiated water temperature

Abstract

The present invention relates to the field of energy-saving technology, and in particular to an online temperature control method and system for differentiated water temperature, the system comprising: an ejector, a data acquisition unit, and a control unit; the method comprising obtaining the temperature fluctuation frequency of the water outlet to determine whether the temperature stability of the outlet water is qualified; obtaining the pressure gradient of the diffusion chamber to determine the temperature fluctuation characteristics of the outlet water based on the judgment result of whether the smoothness of the pressure gradient is qualified; determining the temperature boundary of the detection mixing chamber based on the judgment result of the radial temperature fluctuation to determine the pressure adjustment coefficient of the main fluid pressure according to the axial distance of the stable area of ​​the temperature boundary, or determining the relative humidity of the detection mixing chamber based on the judgment result of the axial temperature fluctuation to determine the pressure adjustment coefficient of the main fluid pressure according to the extinction coefficient of the relative humidity; determining whether the ejection ratio of the main fluid to the secondary fluid is qualified according to the pressure pulsation amplitude of the mixing chamber to optimize the pressure adjustment coefficient. The present invention improves the temperature stability of the water outlet.

Description

Technical Field

[0001] The present invention relates to the field of energy-saving technology, and in particular to an online temperature control method and system for differentiated water temperatures. Background Art

[0002] The ejector nozzle is exposed to high-temperature water for a long time, and the hard components in the water (such as calcium, magnesium and other minerals) are easily precipitated on the inner wall of the nozzle and form scale. As the scale layer accumulates, the effective flow diameter of the nozzle gradually decreases, resulting in a significant increase in its flow rate due to the reduction in cross-sectional area under the condition of constant pressure of the main fluid. At this time, the flow rate matching relationship between the main fluid and the secondary fluid is broken, and the fluid dynamic balance inside the ejector is destroyed, resulting in intensified turbulence in the mixing section and increased energy loss. This problem is directly manifested in fluctuations in the system outlet water temperature, decreased heat exchange efficiency, and even causes the ejector to become unstable. Although the existing technology improves energy efficiency by optimizing the exhaust pressure or adjusting the structural parameters of the ejector, it has not effectively solved the long-term interference of the dynamic accumulation of scale on the flow rate matching.

[0003] Chinese Patent Publication No. CN108981159A discloses a water heater and a control method for the water heater. The water heater includes a heat exchanger casing, a water tank, and a drain line. The heat exchanger casing is provided with a first cold water inlet and a second cold water inlet. The water tank is connected to the first cold water inlet via a first pipeline and to the second cold water inlet via a second pipeline. The first end of the drain line is connected to the second cold water inlet, and the second end of the drain line is connected to the water tank. Applying the technical solution of this invention, after the water heater is out of operation, the drain line can drain the domestic water remaining in the heat exchanger casing back into the water tank, preventing scaling of the heat exchanger casing due to the long-term storage of domestic water. This ensures the heat exchange efficiency of the heat exchanger casing, thereby improving the energy efficiency of the water heater and making it more energy-efficient. Furthermore, draining the domestic water from the heat exchanger casing can prevent the water discharged from the heat exchanger casing from freezing and cracking in low-temperature environments.

[0004] The following problems also exist in the existing technology: when the water heater uses an ejector for temperature control, scale caused by long-term use accumulates on the working nozzle, causing the diameter of the working nozzle to decrease, thereby causing the flow rate of the main fluid to increase under the condition of constant pressure, causing the ejection ratio of the main fluid and the secondary fluid to be unbalanced, and ultimately resulting in insufficient temperature stability at the final water outlet. Summary of the Invention

[0005] To this end, the present invention provides an online temperature control method and system for differentiated water temperature, so as to overcome the problem in the prior art of low temperature stability of the water outlet due to the reduction of the working nozzle diameter.

[0006] To achieve the above objectives, the present invention provides, on the one hand, a method for online temperature control of differentiated water temperature, comprising:

[0007] Obtain the temperature fluctuation frequency of the water outlet to determine whether the temperature stability of the water outlet is qualified;

[0008] Under the condition that the temperature stability of the outlet water is determined to be unqualified, obtaining the pressure gradient of the diffusion chamber to determine the temperature fluctuation characteristics of the outlet water based on the result of determining that the smoothness of the pressure gradient is qualified;

[0009] Determining a temperature boundary of the detection mixing chamber based on a determination result that the temperature fluctuation characteristic is radial temperature fluctuation, and determining a pressure adjustment coefficient of the main fluid pressure according to an axial distance of a stable region of the temperature boundary;

[0010] Alternatively, based on the determination result that the temperature fluctuation characteristic is axial temperature fluctuation, the relative humidity of the detection mixing chamber is determined to determine the pressure adjustment coefficient of the main fluid pressure according to the extinction coefficient of the relative humidity;

[0011] Whether the injection ratio of the primary fluid to the secondary fluid is qualified is determined according to the pressure pulsation amplitude of the mixing chamber to optimize the pressure adjustment coefficient.

[0012] Furthermore, the process of determining whether the temperature stability of the outlet water is qualified according to the temperature fluctuation frequency includes:

[0013] comparing the temperature fluctuation frequency with a preset frequency;

[0014] Based on the comparison result that the temperature fluctuation frequency is greater than the preset frequency, it is determined that the temperature stability of the outlet water is unqualified.

[0015] Furthermore, the process of determining the smoothness of the pressure gradient of the diffusion chamber includes:

[0016] Taking the inlet pressure at the inlet of the diffusion chamber as the reference pressure, the gradient pressures at several positions are determined in sequence with a preset length as the interval;

[0017] Subtracting the reference pressure from the gradient pressure to obtain a plurality of gradient difference values ​​to establish a gradient pressure broken line;

[0018] The ratio of the number of line segments in the portion where the gradient pressure broken line overlaps with the standard gradient pressure broken line to the total number of line segments is determined as the smoothness of the pressure gradient.

[0019] Furthermore, the process of determining whether the smoothness of the pressure gradient is qualified includes:

[0020] comparing the smoothness with a preset smoothness;

[0021] determining that the smoothness of the pressure gradient is unqualified based on a comparison result that the smoothness is less than the preset smoothness;

[0022] The smoothness of the pressure gradient is determined to be qualified based on a comparison result that the smoothness is greater than or equal to the preset smoothness.

[0023] Furthermore, under the condition that the smoothness is determined to be unqualified, the process of determining the temperature fluctuation characteristics of the outlet water according to the change in the number of vortices in the diffusion chamber includes:

[0024] determining whether the change in the number of vortices is a periodic change or a non-periodic change;

[0025] determining to start the acoustic wave disturbance based on a determination result of the periodic change in the number of vortices;

[0026] Determining temperature fluctuation characteristics based on the determination result of the non-periodic change in the number of vortices to determine corresponding detection parameters;

[0027] Wherein, the temperature fluctuation characteristics include radial temperature fluctuations and axial temperature fluctuations. When the temperature fluctuation characteristics are determined to be radial temperature fluctuations, the temperature boundary of the mixing chamber is determined to be detected. When the temperature fluctuation characteristics are determined to be axial temperature fluctuations, the relative humidity of the mixing chamber is determined to be detected.

[0028] Furthermore, the process of determining the temperature boundary includes:

[0029] Acquire multiple image information of the mixing chamber, and determine the grayscale gradients of multiple pixel blocks based on the single image information;

[0030] comparing the grayscale gradient with a preset gradient;

[0031] A curve formed by connecting a number of pixel blocks whose grayscale gradient is greater than or equal to the preset gradient is determined as a temperature boundary.

[0032] Furthermore, the process of determining the corresponding pressure adjustment coefficient of the main fluid pressure according to the temperature boundary includes:

[0033] determining a stable region of the temperature boundary based on a plurality of image information;

[0034] A pressure adjustment coefficient of the corresponding main fluid pressure is determined based on the axis distance of the stable region.

[0035] Furthermore, the process of determining whether the injection ratio of the primary fluid to the secondary fluid is qualified includes:

[0036] comparing the pressure pulsation amplitude of the mixing chamber with a preset amplitude;

[0037] Based on the comparison result that the pressure pulsation amplitude is greater than the preset amplitude, it is determined that the injection ratio of the primary fluid to the secondary fluid is unqualified.

[0038] Furthermore, under the condition that the injection ratio of the primary fluid to the secondary fluid is determined to be unqualified, the process of optimizing the pressure adjustment coefficient includes:

[0039] Subtracting the pressure pulsation amplitude from the preset amplitude to obtain a difference value;

[0040] A plurality of correction coefficients corresponding to the difference are set to reduce the pressure adjustment coefficient based on the correction coefficients.

[0041] On the other hand, the present invention also provides an online temperature control system for differentiated water temperature, comprising:

[0042] Heat exchanger, water system, several ejectors;

[0043] a data acquisition module connected to the ejector, comprising a temperature sensor disposed at the water outlet, a plurality of image sensors disposed inside the diffusion chamber and the mixing chamber of the ejector, a pressure sensor disposed inside the diffusion chamber for detecting pressure, and a humidity sensor disposed inside the mixing chamber for detecting relative humidity;

[0044] A control module, connected to the data acquisition module, comprising:

[0045] a temperature detection unit, configured to determine a temperature fluctuation frequency and a temperature fluctuation characteristic based on the detection result of the temperature sensor, so as to determine whether the temperature stability at the water outlet is qualified based on the temperature fluctuation frequency, and to determine a temperature boundary or relative humidity of the mixing chamber based on the temperature fluctuation characteristic;

[0046] a pressure detection unit, configured to determine whether the smoothness of the pressure gradient is qualified according to the detection result of the pressure sensor;

[0047] an image detection unit, configured to determine the number of vortices in the diffusion chamber according to a detection result of the image sensor to determine the start of acoustic wave disturbance or determine temperature fluctuation characteristics;

[0048] The regulating unit is configured to determine a pressure regulating coefficient of the main fluid pressure based on the stable region of the temperature boundary or the extinction coefficient of the relative humidity, so as to regulate the pressure regulating coefficient according to the pressure pulsation amplitude of the mixing chamber.

[0049] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention determines whether the temperature stability of the water outlet is qualified by setting a temperature sensor at the water outlet of the water heater to determine the temperature fluctuation frequency, and confirms the pressure gradient of the diffusion chamber under the condition that the water outlet temperature is unqualified, so as to determine whether the unstable water outlet temperature is due to incomplete mixing of high and low temperature water caused by unqualified smoothness of the pressure gradient in the diffusion chamber, or uneven temperature caused by unqualified mixing of high and low temperature water in the mixing chamber; under the condition that the smoothness of the pressure gradient is determined to be unqualified, the acoustic wave disturbance device is turned on to break large-scale vortices into small-scale vortices through energy level series dissipation, thereby improving the smoothness of the pressure gradient; under the condition that the smoothness of the pressure gradient is determined to be qualified, the temperature fluctuation characteristics are further determined to determine whether it is axial temperature fluctuation or radial temperature fluctuation, and the corresponding detection parameters are determined according to different temperature fluctuation states, and then the pressure adjustment coefficient of the main fluid pressure is determined according to the value of the detection parameter, and the pressure adjustment coefficient is corrected, thereby improving the flow rate matching of the main fluid and the secondary fluid, and further improving the temperature stability of the water outlet.

[0050] Furthermore, the present invention monitors the pressure gradient in the diffusion chamber and determines the smoothness of the pressure gradient based on the number of overlapping line segments of the gradient pressure broken line and the standard curve. A qualified smoothness indicates that the temperature mixing process in the diffusion chamber is qualified, and an unqualified smoothness indicates that the temperature mixing in the mixing chamber has not reached the required degree, resulting in the subsequent mixing process in the diffusion chamber being qualified, but the final water outlet temperature stability is still unqualified. The process that leads to the unqualified temperature stability is determined based on the smoothness of the pressure gradient, and targeted detection and adjustment are performed, thereby further improving the temperature stability of the water outlet.

[0051] Furthermore, the present invention further determines whether the temperature fluctuation characteristics are radial temperature fluctuations or axial temperature fluctuations under the condition of determining that the smoothness is unqualified. The radial temperature fluctuation is due to the local pressure pulsation caused by the periodic generation and collapse of cavitation bubbles, which leads to fluctuations in the heat transfer rate, thereby causing the fluid temperature mixing uniformity to decrease, and the temperature at the water outlet to show radial fluctuations; the axial temperature fluctuation is due to the high-temperature main fluid entering the mixing chamber in the form of a jet, and the secondary fluid forms a circulation on the wall. A shear layer is formed between the jet core area and the circulation, and the turbulent pulsation at the interface is enhanced. The jet and the circulation interact with each other, inducing secondary flows such as horseshoe vortexes and Taylor vortices. The secondary flows carry high-temperature / low-temperature fluids to alternately flush the outlet of the mixing chamber, causing the outlet temperature to show axial fluctuations; targeted adjustments are made according to the specific circumstances of the temperature fluctuation, thereby further improving the temperature stability of the water outlet.

[0052] Furthermore, the present invention improves the water temperature stability of each water outlet by monitoring the water temperature of water outlets with different temperatures and performing targeted detection and adjustment on water outlets with insufficient temperature stability, thereby improving the temperature stability of differentiated water temperatures of the water heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a flow chart of an online temperature control method for differentiated water temperature according to an embodiment of the present invention;

[0054] Figure 2 This is a flow chart for determining whether the temperature stability of a water outlet is qualified according to an embodiment of the present invention;

[0055] Figure 3 A flow chart for determining whether the smoothness of a pressure gradient is qualified according to an embodiment of the present invention;

[0056] Figure 4 This is a structural block diagram of an online temperature control system for differentiated water temperature according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0058] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0059] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0060] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0061] See also Figure 1-Figure 3 As shown, Figure 1This is a flow chart of an online temperature control method for differentiated water temperature according to an embodiment of the present invention; Figure 2 This is a flow chart for determining whether the temperature stability of a water outlet is qualified according to an embodiment of the present invention; Figure 3 This is a flow chart for determining whether the smoothness of the pressure gradient is qualified according to an embodiment of the present invention.

[0062] An embodiment of the present invention provides an online temperature control method for differentiated water temperature, characterized by comprising:

[0063] Step S1, obtaining the temperature fluctuation frequency of the water outlet to determine whether the temperature stability of the water outlet is qualified;

[0064] Step S2, when it is determined that the temperature stability of the outlet water is unqualified, obtaining the pressure gradient of the diffusion chamber to determine the temperature fluctuation characteristics of the outlet water based on the result of determining that the smoothness of the pressure gradient is qualified;

[0065] Step S3, based on the determination result that the temperature fluctuation characteristic is radial temperature fluctuation, the temperature boundary of the detection mixing chamber is determined to determine the pressure adjustment coefficient of the main fluid pressure according to the axial distance of the stable area of ​​the temperature boundary,

[0066] Alternatively, based on the determination result that the temperature fluctuation characteristic is axial temperature fluctuation, the relative humidity of the detection mixing chamber is determined to determine the pressure adjustment coefficient of the main fluid pressure according to the extinction coefficient of the relative humidity;

[0067] Step S4: determining whether the injection ratio of the primary fluid to the secondary fluid is qualified according to the pressure pulsation amplitude of the mixing chamber to optimize the pressure adjustment coefficient.

[0068] Specifically, the process of determining whether the temperature stability of the outlet water is qualified based on the temperature fluctuation frequency includes:

[0069] comparing the temperature fluctuation frequency with a preset frequency;

[0070] Determining that the temperature stability of the outlet water is unqualified based on a comparison result that the temperature fluctuation frequency is greater than the preset frequency;

[0071] The temperature stability of the water outlet is determined to be qualified based on the comparison result that the temperature fluctuation frequency is less than or equal to the preset frequency.

[0072] Specifically, the process of determining the temperature fluctuation frequency includes:

[0073] Recording the actual temperature at the water outlet in real time to establish a temperature curve, and comparing the temperature curve with a preset temperature range;

[0074] The temperature fluctuation frequency is determined by comparing the number of peaks of the temperature curve exceeding the preset temperature range with the corresponding time.

[0075] Specifically, the preset temperature range is the range between two straight lines parallel to the horizontal axis. The temperatures corresponding to the two straight lines are the maximum and minimum temperatures allowed to fluctuate in the design temperature of the water outlet. For example, if the design temperature at the water outlet is 50°C and the allowable fluctuation temperature is ±1°C, then the temperatures corresponding to the two straight lines are 49°C and 51°C respectively.

[0076] Specifically, the process of determining the smoothness of the pressure gradient of the diffusion chamber includes:

[0077] Taking the inlet pressure at the inlet of the diffusion chamber as the reference pressure, the gradient pressures at several positions are determined in sequence with a preset length as the interval;

[0078] Subtracting the reference pressure from the gradient pressure to obtain a plurality of gradient difference values ​​to establish a gradient pressure broken line;

[0079] The ratio of the number of line segments in the portion where the gradient pressure broken line overlaps with the standard gradient pressure broken line to the total number of line segments is determined as the smoothness of the pressure gradient.

[0080] Specifically, the preset length is determined according to the length of the diffusion chamber. For example, if the length of the diffusion chamber is 15 cm, the preset length is set to 1 cm.

[0081] Specifically, the standard gradient pressure broken line is the average value of the pressure gradient of the diffusion chamber with qualified temperature stability of the water outlet in the historical process.

[0082] Specifically, the greater the ratio of the number of line segments in the portion where the gradient pressure broken line overlaps with the standard gradient pressure broken line to the total number of line segments, the better the smoothness.

[0083] Specifically, the process of determining whether the smoothness of the pressure gradient is qualified includes:

[0084] comparing the smoothness with a preset smoothness;

[0085] determining that the smoothness of the pressure gradient is unqualified based on a comparison result that the smoothness is less than the preset smoothness;

[0086] The smoothness of the pressure gradient is determined to be qualified based on a comparison result that the smoothness is greater than or equal to the preset smoothness.

[0087] Specifically, the value of the preset smoothness is determined according to the temperature instability that occurs in the historical process, and the value range is set to [0.6, 0.8]. In the embodiment of the present invention, 0.7 is preferred.

[0088] Specifically, under the condition that the smoothness is determined to be unqualified, the process of determining the temperature fluctuation characteristics of the outlet water according to the change in the number of vortices in the diffusion chamber includes:

[0089] determining whether the change in the number of vortices is a periodic change or a non-periodic change;

[0090] determining to start the acoustic wave disturbance based on a determination result of the periodic change in the number of vortices;

[0091] Determining temperature fluctuation characteristics based on the determination result of the non-periodic change in the number of vortices to determine corresponding detection parameters;

[0092] Wherein, the temperature fluctuation characteristics include radial temperature fluctuations and axial temperature fluctuations. When the temperature fluctuation characteristics are determined to be radial temperature fluctuations, the temperature boundary of the mixing chamber is determined to be detected. When the temperature fluctuation characteristics are determined to be axial temperature fluctuations, the relative humidity of the mixing chamber is determined to be detected.

[0093] Specifically, when the liquid flow rate at the inlet of the diffusion chamber is too large, a low-pressure area will appear in the diffusion chamber, forming a pressure gradient difference with the mainstream area. In the corners or near the side walls of the diffusion chamber, boundary layer separation causes periodic vortex shedding, which causes pressure gradient fluctuations. After turning on the acoustic perturbation device, the sound waves can excite cavitation bubbles in the fluid. The microjets generated by cavitation interact with the vortices, and the large-scale vortices are broken into small-scale vortices through energy level series dissipation. At the same time, the microscale flow caused by the sound waves is superimposed on the mainstream momentum to form a secondary flow field, which reduces the amplitude of the pressure gradient mutation caused by vortex shedding, thereby increasing the smoothness of the pressure gradient.

[0094] Specifically, the process of determining the periodic change of the vortex number includes:

[0095] Taking the time point when the temperature stability fails to meet the requirements as the starting point, the number of vortices is monitored in real time;

[0096] A quantity curve is established based on the change in the number of vortices, and the portion below the symmetry axis is mirrored to a position above the symmetry axis, with the straight line between the midpoints of the peak and the trough of the quantity curve being the symmetry axis;

[0097] According to the mirrored curve, any peak is taken as the reference peak, and all other peaks are overlapped with the reference peak to determine the overlap area of ​​the waves;

[0098] Waves with an overlapping area greater than 80% are identified as periodic waves, and the ratio of periodic waves to non-periodic waves is calculated.

[0099] Determining that the number of vortices presents a periodic change based on a comparison result that the number ratio is greater than or equal to a preset number ratio;

[0100] It is determined that the number of vortices exhibits a non-periodic change based on a comparison result that the number ratio is less than a preset number ratio.

[0101] Specifically, the wave with an overlapping area greater than 80% is determined as 80% of the periodic wave, and the value is obtained by statistics during the historical use of the water heater. The value of the preset number ratio is set to [1.3, 2], and 1.8 is preferred in the embodiment of the present invention.

[0102] It can be understood that if there is radial temperature fluctuation (such as an annular heat source), the temperature fluctuation diffuses in the form of radial conduction, and it is necessary to locate the boundary of the hot and cold zones by detecting the temperature boundary to determine whether the heat conduction rate is qualified; if there is axial temperature fluctuation, the axial temperature fluctuation is due to the high-temperature main fluid entering the mixing chamber in the form of a jet, and the secondary fluid forms a circulation on the wall. A shear layer is formed between the core area of ​​the jet and the circulation, and the turbulent pulsation at the interface is enhanced. The jet and the circulation interact with each other, inducing secondary flows such as horseshoe vortices and Taylor vortices, and cavitation bubbles will appear. The collapse of the cavitation bubbles will lead to the appearance of white fog.

[0103] Specifically, the process of determining the radial temperature fluctuation includes:

[0104] Taking the center temperature of the water outlet section as the benchmark, divide the area into several rings with a preset radius and determine the average temperature of each ring;

[0105] Calculating the temperature standard deviation between the center temperature and each of the average temperatures;

[0106] Determining that the temperature fluctuation feature is radial temperature fluctuation based on a comparison result that the temperature standard deviation is greater than a preset standard deviation;

[0107] The temperature fluctuation characteristic is determined to be a non-radial temperature fluctuation based on a comparison result that the temperature standard deviation is less than or equal to a preset standard deviation.

[0108] Specifically, the value of the preset standard deviation is determined according to the historical usage process of the water heater, and the specific range is set to [0.3, 0.6]. In the embodiment of the present invention, 0.5 is preferred.

[0109] Specifically, the process of determining the axial temperature fluctuation includes:

[0110] Obtain several center temperatures of the nozzle cross section with a period of 1s;

[0111] Determining the temperature fluctuation characteristic as axial temperature fluctuation based on a comparison result that the absolute value of the center temperature gradient is greater than or equal to 5° C.;

[0112] Based on the comparison result that the absolute value of the center temperature gradient is less than 5° C., it is determined that the temperature fluctuation feature is non-axial temperature fluctuation.

[0113] Specifically, the determination condition of the temperature fluctuation characteristic is determined according to the historical usage process of the water heater.

[0114] Specifically, the process of determining the temperature boundary includes:

[0115] Acquire multiple image information of the mixing chamber, and determine the grayscale gradients of multiple pixel blocks based on the single image information;

[0116] comparing the grayscale gradient with a preset gradient;

[0117] A curve formed by connecting a number of pixel blocks whose grayscale gradient is greater than or equal to the preset gradient is determined as a temperature boundary.

[0118] Specifically, the image information is an infrared thermal image. The main fluid is high-temperature water, which appears warm in the thermal infrared image, and low-temperature water appears cold. There is a grayscale gradient in the grayscale image.

[0119] It can be understood that several pixel blocks with grayscale gradient greater than or equal to the preset gradient are a boundary point set. Based on the boundary point set, a continuous and smooth curve can be formed by applying image processing technology, and the curve is determined as the temperature boundary.

[0120] Specifically, the value of the preset gradient is determined according to the grayscale in the thermal infrared images of high-temperature water and low-temperature water, and the specific range is set to [90, 150]. In the embodiment of the present invention, 120 is preferably selected.

[0121] Specifically, a stable region of the temperature boundary is determined based on a plurality of images, and a pressure adjustment coefficient of the corresponding main fluid pressure is determined based on an axis distance of the stable region;

[0122] Alternatively, a corresponding pressure adjustment coefficient is determined according to the relative humidity.

[0123] Specifically, the process of determining the corresponding pressure adjustment coefficient of the main fluid pressure according to the temperature boundary includes:

[0124] determining a stable region of the temperature boundary based on a plurality of image information;

[0125] A pressure adjustment coefficient of the corresponding main fluid pressure is determined based on the axis distance of the stable region.

[0126] Specifically, the main fluid continuously enters the ejector in the form of a jet, and the temperature boundary between the high-temperature water and the low-temperature water forms a dynamic equilibrium. The range of change of the temperature boundary, that is, the stable area, is determined based on several images. The axial distance is the length of the stable area corresponding to the method along the center line of the working nozzle, which characterizes the matching relationship between the flow velocity of the main fluid and the flow velocity of the secondary fluid.

[0127] Specifically, a corresponding relationship between the axis distance and the pressure adjustment coefficient is preset. It can be understood that the axis distance and the pressure adjustment coefficient are in a positive correlation.

[0128] Specifically, the process of determining whether the injection ratio of the primary fluid to the secondary fluid is qualified includes:

[0129] comparing the pressure pulsation amplitude of the mixing chamber with a preset amplitude;

[0130] Determining that the ejection ratio of the primary fluid to the secondary fluid is unqualified based on a comparison result that the pressure pulsation amplitude is greater than the preset amplitude;

[0131] The injection ratio of the primary fluid to the secondary fluid is determined to be qualified based on a comparison result that the pressure pulsation amplitude is less than or equal to the preset amplitude.

[0132] Specifically, if the flow rate of the main fluid is too high, high-frequency noise will occur in the mixing chamber, which will cause the pressure in the mixing chamber to fluctuate. The larger the pressure pulsation amplitude, the greater the degree of unqualified injection ratio.

[0133] Specifically, the value of the preset amplitude is obtained based on statistical analysis of historical usage data, and the specific range is set to [3%, 15%]. In the embodiment of the present invention, 5% is preferred. It can be understood that the amplitude is the absolute difference in pressure change.

[0134] Specifically, under the condition that the injection ratio of the primary fluid to the secondary fluid is determined to be unqualified, the process of optimizing the pressure adjustment coefficient includes:

[0135] Subtracting the pressure pulsation amplitude from the preset amplitude to obtain a difference value;

[0136] A plurality of correction coefficients corresponding to the difference are set to reduce the pressure adjustment coefficient based on the correction coefficients.

[0137] Specifically, the regulating module subtracts the pressure pulsation amplitude from a preset amplitude to obtain a difference value;

[0138] comparing the difference with a preset difference;

[0139] determining to reduce the pressure adjustment coefficient by a first correction coefficient based on a comparison result that the difference is greater than the preset difference;

[0140] Based on a comparison result that the difference is less than or equal to the preset difference, it is determined to reduce the pressure adjustment coefficient by a second correction coefficient.

[0141] Specifically, the value of the preset difference is obtained by statistically analyzing the data of the historical usage process, and the specific range is set to [1%, 3%], and 2% is preferably used in the embodiment of the present invention; the value range of the first correction coefficient is set to [0.991, 0.994], and 0.993 is preferably used in the embodiment of the present invention;

[0142] The value range of the second correction coefficient is set to [0.9941, 0.997], and 0.995 is preferably used in the embodiment of the present invention.

[0143] See also Figure 4 As shown, it is a structural block diagram of an online temperature control system for differentiated water temperature according to an embodiment of the present invention.

[0144] The embodiment of the present invention further provides an online temperature control system for differentiated water temperature, comprising:

[0145] Heat exchanger, water system, several ejectors;

[0146] a data acquisition module connected to the ejector, comprising a temperature sensor disposed at the water outlet, a plurality of image sensors disposed inside the diffusion chamber and the mixing chamber of the ejector, a pressure sensor disposed inside the diffusion chamber for detecting pressure, and a humidity sensor disposed inside the mixing chamber for detecting relative humidity;

[0147] A control module, connected to the data acquisition module, comprising:

[0148] a temperature detection unit, configured to determine a temperature fluctuation frequency and a temperature fluctuation characteristic based on the detection result of the temperature sensor, so as to determine whether the temperature stability at the water outlet is qualified based on the temperature fluctuation frequency, and to determine a temperature boundary or relative humidity of the mixing chamber based on the temperature fluctuation characteristic;

[0149] a pressure detection unit, configured to determine whether the smoothness of the pressure gradient is qualified according to the detection result of the pressure sensor;

[0150] an image detection unit, configured to determine the number of vortices in the diffusion chamber according to a detection result of the image sensor to determine the start of acoustic wave disturbance or determine temperature fluctuation characteristics;

[0151] The regulating unit is configured to determine a pressure regulating coefficient of the main fluid pressure based on the stable region of the temperature boundary or the extinction coefficient of the relative humidity, so as to regulate the regulating coefficient according to the pressure pulsation amplitude of the mixing chamber.

[0152] In an embodiment of the present invention, the heat exchanger includes a heat medium inlet and a heat medium outlet. The heat medium heats the cold water to a predetermined temperature through the heat exchanger. The heat exchanger also includes a water outlet. The hot water output through the water outlet is transported through a hot water pipe, and a number of ejectors are provided on the hot water pipe. A cold water pipe is provided at the position of the hot water pipe corresponding to the ejector. The cold water in the cold water pipe serves as the secondary fluid, and the hot water in the hot water pipe serves as the primary fluid. After being mixed by the corresponding ejectors, they are output as water at a set temperature.

[0153] Specifically, the heat medium may be steam, high-temperature water, or thermal oil, but is not limited thereto. The water temperature output by the heat exchanger may be 85° C., which is not specifically limited.

[0154] In the embodiment of the present invention, there are three ejectors, and the water temperatures output by the corresponding ejectors are 60°C, 45°C and 82°C respectively, but the present invention is not limited thereto. The output water temperature can be adjusted or set according to actual requirements.

[0155] Specifically, the energy-saving system of the water heater in the embodiment of the present invention uses an ejector to mix the main fluid, high-temperature water, for example, 85°C, with the secondary fluid, low-temperature water, for example, 10°C, at different flow rates according to the outlet water temperature requirements to meet the temperature requirements; however, when using 85°C high-temperature water and 10°C low-temperature water to mix, under the same working nozzle conditions, the high-temperature water flow rate is large, resulting in a fast flow rate, and the flow rate difference with the low-temperature water is too large, which can easily lead to an imbalance in the ejection ratio of the main fluid and the secondary fluid, resulting in insufficient stability of the outlet water temperature. At the same time, under long-term use conditions, the hard components in the high-temperature water will be extracted and attached to the working nozzle, resulting in a reduction in the diameter of the working nozzle. Under the condition that the main fluid pressure remains unchanged, the main fluid flow rate will increase, resulting in an imbalance in the ejection ratio, resulting in unstable outlet water temperature.

[0156] Specifically, the ejector can be a jet pump ejector or a venturi ejector. The specific model and parameters are not limited, and it only needs to meet the use requirements of the water heater.

[0157] Specifically, the temperature sensor, image sensor, pressure sensor and humidity sensor are all commercially available products, and the parameters of specific models are not limited, as long as they meet the detection requirements.

[0158] Specifically, the extinction coefficient is determined by a laser transmission measurement device disposed in the mixing chamber, wherein the laser transmission measurement device includes a laser light source, a light receiving system, and a data acquisition and analysis system.

[0159] Specifically, the difference in flow rate between the primary fluid and the secondary fluid will cause the pressure in the mixing chamber to fluctuate violently, triggering the generation and collapse of cavitation bubbles. The compression work released at the moment of cavitation collapse is converted into heat energy, causing a sudden rise in local temperature. The heat then diffuses to the surrounding area, causing water vapor to condense into tiny droplets, forming white mist. The concentration of white mist is positively correlated with the degree of difference in flow rate between the primary fluid and the secondary fluid. The extinction coefficient is positively correlated with the concentration of white mist. The greater the concentration of white mist, the greater the relative humidity in the mixing chamber. Therefore, the corresponding relationship between the extinction coefficient and relative humidity can be established based on the relative humidity.

[0160] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for online temperature control of differentiated water temperature, characterized in that: include: Obtain the temperature fluctuation frequency of the water outlet to determine whether the temperature stability of the water outlet is qualified; Under the condition that the temperature stability of the outlet water is determined to be unqualified, obtaining the pressure gradient of the diffusion chamber to determine the temperature fluctuation characteristics of the outlet water based on the result of determining that the smoothness of the pressure gradient is qualified; Determining a temperature boundary of the detection mixing chamber based on a determination result that the temperature fluctuation characteristic is radial temperature fluctuation, and determining a pressure adjustment coefficient of the main fluid pressure according to an axial distance of a stable region of the temperature boundary; Alternatively, based on the determination result that the temperature fluctuation characteristic is axial temperature fluctuation, the relative humidity of the detection mixing chamber is determined to determine the pressure adjustment coefficient of the main fluid pressure according to the extinction coefficient of the relative humidity; Whether the injection ratio of the primary fluid to the secondary fluid is qualified is determined according to the pressure pulsation amplitude of the mixing chamber to optimize the pressure adjustment coefficient.

2. The online temperature control method for differentiated water temperature according to claim 1, characterized in that: The process of determining whether the temperature stability of the outlet water is qualified based on the temperature fluctuation frequency includes: comparing the temperature fluctuation frequency with a preset frequency; Based on the comparison result that the temperature fluctuation frequency is greater than the preset frequency, it is determined that the temperature stability of the outlet water is unqualified.

3. The online temperature control method for differentiated water temperature according to claim 2, characterized in that: The process of determining the smoothness of the pressure gradient in the diffusion chamber includes: Taking the inlet pressure at the inlet of the diffusion chamber as the reference pressure, the gradient pressures at several positions in the diffusion chamber are determined in sequence at intervals of a preset length; Subtracting the reference pressure from the gradient pressure to obtain a plurality of gradient difference values ​​to establish a gradient pressure broken line; The ratio of the number of line segments in the portion where the gradient pressure broken line overlaps with the standard gradient pressure broken line to the total number of line segments is determined as the smoothness of the pressure gradient.

4. The online temperature control method for differentiated water temperature according to claim 3, characterized in that: The process of determining whether the smoothness of the pressure gradient is qualified includes: comparing the smoothness with a preset smoothness; determining that the smoothness of the pressure gradient is unqualified based on a comparison result that the smoothness is less than the preset smoothness; The smoothness of the pressure gradient is determined to be qualified based on a comparison result that the smoothness is greater than or equal to the preset smoothness.

5. The online temperature control method for differentiated water temperature according to claim 4, characterized in that: Under the condition that the smoothness is determined to be unqualified, the process of determining the temperature fluctuation characteristics of the outlet water according to the change in the number of vortices in the diffusion chamber includes: determining whether the change in the number of vortices is a periodic change or a non-periodic change; determining to start the acoustic wave disturbance based on a determination result of the periodic change in the number of vortices; Determining temperature fluctuation characteristics based on the determination result of the non-periodic change in the number of vortices to determine corresponding detection parameters; Wherein, the temperature fluctuation characteristics include radial temperature fluctuations and axial temperature fluctuations. When the temperature fluctuation characteristics are determined to be radial temperature fluctuations, the temperature boundary of the mixing chamber is determined to be detected. When the temperature fluctuation characteristics are determined to be axial temperature fluctuations, the relative humidity of the mixing chamber is determined to be detected.

6. The online temperature control method for differentiated water temperature according to claim 5, characterized in that: The process of determining the temperature boundary includes: Acquire multiple image information of the mixing chamber, and determine the grayscale gradients of multiple pixel blocks based on the single image information; comparing the grayscale gradient with a preset gradient; A curve formed by connecting a number of pixel blocks whose grayscale gradient is greater than or equal to the preset gradient is determined as a temperature boundary.

7. The online temperature control method for differentiated water temperature according to claim 6, characterized in that: The process of determining the corresponding pressure adjustment coefficient of the main fluid pressure according to the temperature boundary includes: determining a stable region of the temperature boundary based on a plurality of image information; A pressure adjustment coefficient of the corresponding main fluid pressure is determined based on the axis distance of the stable region.

8. The online temperature control method for differentiated water temperature according to claim 7, characterized in that: The process of determining whether the injection ratio of the primary fluid to the secondary fluid is qualified includes: comparing the pressure pulsation amplitude of the mixing chamber with a preset amplitude; Based on the comparison result that the pressure pulsation amplitude is greater than the preset amplitude, it is determined that the injection ratio of the primary fluid to the secondary fluid is unqualified.

9. The online temperature control method for differentiated water temperature according to claim 8, characterized in that: Under the condition that the injection ratio of the primary fluid to the secondary fluid is determined to be unqualified, the process of optimizing the pressure adjustment coefficient includes: Subtracting the pressure pulsation amplitude from the preset amplitude to obtain a difference value; A plurality of correction coefficients corresponding to the difference are set to reduce the pressure adjustment coefficient based on the correction coefficients.

10. An online temperature control system using the online temperature control method for differentiated water temperature according to any one of claims 1 to 9, comprising a heat exchanger and a water system, characterized in that: Also includes: Several ejectors; a data acquisition module connected to the ejector, comprising a temperature sensor disposed at the water outlet, a plurality of image sensors disposed inside the diffusion chamber and the mixing chamber of the ejector, a pressure sensor disposed inside the diffusion chamber for detecting pressure, and a humidity sensor disposed inside the mixing chamber for detecting relative humidity; A control module, connected to the data acquisition module, comprising: a temperature detection unit, configured to determine a temperature fluctuation frequency and a temperature fluctuation characteristic based on the detection result of the temperature sensor, so as to determine whether the temperature stability at the water outlet is qualified based on the temperature fluctuation frequency, and to determine a temperature boundary or relative humidity of the mixing chamber based on the temperature fluctuation characteristic; a pressure detection unit, configured to determine whether the smoothness of the pressure gradient is qualified according to the detection result of the pressure sensor; an image detection unit, configured to determine the number of vortices in the diffusion chamber according to a detection result of the image sensor to determine the start of acoustic wave disturbance or determine temperature fluctuation characteristics; The regulating unit is configured to determine a pressure regulating coefficient of the main fluid pressure based on the stable region of the temperature boundary or the extinction coefficient of the relative humidity, so as to regulate the pressure regulating coefficient according to the pressure pulsation amplitude of the mixing chamber.

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