Cold blast prevention control method and water system air conditioner

Abstract

The application discloses a cold wind prevention control method and a water system air conditioner. The cold wind prevention control method comprises the following steps: detecting a current water inlet temperature T1 and a user set temperature T2 after starting a heating operation of an indoor unit; if the current water inlet temperature T1 is less than or equal to the user set temperature T2, the indoor unit is controlled to enter a cold wind prevention mode, a water valve of the indoor unit is opened, and a fan is stopped; the lowest water inlet temperature T 11 required for the indoor unit to blow out wind without cold feeling is calculated; the current water inlet temperature T1 is monitored; when the current water inlet temperature T 11 reaches the lowest water inlet temperature T, the fan of the indoor unit is started to run at a preset lowest wind gear; and the rotating speed of the fan is increased according to the increase of the current water inlet temperature T1 until the rotating speed reaches a target wind gear rotating speed corresponding to the user set temperature. The application realizes accurate blocking of cold wind in a heating starting stage and smooth transition of a blowing process, significantly shortens the waiting time of the user for heating, and reduces the energy consumption of the air conditioner, and belongs to an energy-saving air conditioner.

Description

Technical Field

[0001] This invention relates to the field of air conditioning control technology, and in particular to a method for preventing cold air from entering and a water-cooled air conditioning system. Background Technology

[0002] When a central air conditioning water system is operating for heating in winter, due to the long pipes and the large heat capacity of the water, the high-temperature hot water prepared on the outdoor unit side needs to be transported to each indoor unit through the water circulation system. This results in the inlet water temperature flowing through the heat exchanger coils being relatively low during the initial startup of the indoor unit, failing to meet the heat exchange requirements for immediate heating.

[0003] To prevent cold air from blowing out and affecting the user experience, existing water-cooled air conditioning systems typically employ the following two anti-cold air control strategies:

[0004] 1. When the inlet water temperature is detected to be lower than the user-set temperature, the water valve of the indoor unit is kept closed or slightly open, and the fan stops running completely until the inlet water temperature rises to a safe threshold before the fan starts again. However, this strategy results in the indoor unit remaining in a "silent" and static state for an extended period during startup, which users may mistakenly interpret as a power outage or malfunction, leading to unnecessary after-sales inquiries and complaints. Furthermore, the complete shutdown of the fan also slows down the rate at which the room temperature rises.

[0005] 2. Water temperature can be increased by adjusting the output capacity of the outdoor unit or the speed of the water pump. However, in multi-split water-cooled air conditioning systems, there are numerous indoor units distributed across different rooms, and the start / stop status and temperature control requirements of each room are independent. Adjusting the water temperature of the entire system for a single indoor unit that has just started would severely affect the comfort of other normally operating indoor units and the system's energy efficiency, making the control logic extremely cumbersome.

[0006] Furthermore, in existing methods for controlling cold air, even after the water temperature reaches the target level, the fan is often switched directly to the user-set fan speed (such as medium or high). Since the water temperature is still rising during the initial startup phase, switching directly to a high speed can easily cause fluctuations in the outlet air temperature, or even a secondary cooling before the water temperature has stabilized. This results in an abrupt change in fan speed and cannot guarantee a smooth transition in airflow and temperature.

[0007] Therefore, how to solve the problem of cold air during the initial heating stage of water-cooled air conditioning systems while ensuring user experience, and shorten the waiting time for cold air prevention, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] To address the shortcomings of existing water-cooled air conditioning systems, such as the tendency to blow cold air during the heating start-up phase and the prolonged shutdown of indoor units in anti-cold-air mode, this invention proposes an anti-cold-air control method and a water-cooled air conditioning system. By employing a method that predicts the lowest inlet water temperature, starts the system at the preset lowest fan speed, and adjusts the fan speed based on the inlet water temperature, it not only eliminates the need to adjust the outdoor unit or interrupt the operation of the indoor unit, but also achieves precise blocking of cold air during the heating start-up phase and a smooth transition in the air supply process. This effectively ensures stable outlet air temperature and user comfort throughout the heating process, significantly shortens the waiting time for users to heat up, and reduces the energy consumption of the air conditioning system, making it an energy-saving air conditioning device.

[0009] The technical solution adopted in this invention is to design an anti-cold air control method, applied to the indoor unit of a water-cooled air conditioning system, comprising the following steps:

[0010] After the indoor unit starts heating operation, the current inlet water temperature T1 and the user-set temperature T2 of the indoor unit are detected.

[0011] If the current inlet water temperature T1 is less than or equal to the user-set temperature T2, the indoor unit will be controlled to enter the anti-cold air mode, the water valve of the indoor unit will be opened and the fan will be stopped.

[0012] Calculate the minimum inlet water temperature T required for the indoor unit to produce no cooling sensation when the air is blown out. 11 ;

[0013] Monitor the current inlet water temperature T1. When the current inlet water temperature T1 reaches the minimum inlet water temperature T... 11 When the indoor unit's fan starts running at the preset lowest fan speed, the fan speed is increased according to the increase in the current inlet water temperature T1 until the speed reaches the target fan speed corresponding to the user-set temperature.

[0014] This design prevents the blowout of cold air by starting the fan only when the inlet water temperature reaches the calculated minimum inlet water temperature. It adopts a control logic that starts the fan at the lowest setting and then gradually increases the speed as the inlet water temperature rises, so that the air supply speed transitions smoothly with the rise of water temperature. This effectively solves the problem of user misjudgment caused by the indoor unit being shut down for a long time in the traditional anti-cold air mode, and takes into account both heating start-up speed and comfort.

[0015] Furthermore, the minimum inlet water temperature T required to ensure that the indoor unit's airflow is not cold was calculated. 11 include:

[0016] Obtain the non-cooling temperature T of the indoor unit a ;

[0017] Based on the temperature T where there is no cold sensation a Based on the indoor ambient temperature T3 and the jet airflow attenuation coefficient B, the target outlet air temperature T required to be achieved at the indoor unit's outlet is calculated in reverse. 41 :

[0018] ;

[0019] Based on the target outlet air temperature T 41 Calculate the minimum inlet water temperature T based on the indoor ambient temperature T3 and the heat exchanger's overall efficiency coefficient C. 11 :

[0020] ;

[0021] Among them, the value of B ranges from 1.0 to 2.0, the value of C ranges from 0.6 to 0.8, and C decreases as the air outlet velocity v of the indoor unit increases.

[0022] This design introduces the temperature at which no cooling is felt as the control benchmark. By combining the jet blowing attenuation coefficient and the heat exchanger's overall efficiency coefficient for inverse calculation, it can accurately quantify the minimum inlet water temperature threshold required for no cooling in the airflow. Compared to empirical threshold control, this calculation method fully considers the influence of ambient temperature and equipment heat exchange efficiency, improving the accuracy and reliability of anti-cold air control.

[0023] In some embodiments, in application scenarios where the indoor unit is installed at a height of 3 meters and the air outlet distance is 1.5 meters, the temperature T without cooling sensation is... a Through formula calculate;

[0024] Where A is the variation coefficient, with a value ranging from 3 to 4, and v is the air outlet speed of the indoor unit.

[0025] This design targets a typical installation scenario with a ceiling height of 3 meters and an air outlet distance of 1.5 meters. It employs a simplified logarithmic formula to calculate the temperature without the feeling of cold, significantly reducing the controller's computational load while maintaining control accuracy. This formula is highly adaptable and easily implemented in conventional household water-cooled air conditioning systems, thus helping to reduce the product's hardware and software costs.

[0026] In some embodiments, the temperature T without cooling sensation a Through formula calculate;

[0027] Where T is the target air outlet temperature of the indoor unit; v is the air outlet velocity of the indoor unit; and x is the distance between the user's location and the air outlet of the indoor unit. It is a positive correlation function that increases with increasing outlet air velocity; It is a negative correlation function that decreases as the distance increases.

[0028] This design incorporates the current air outlet temperature and the user's distance as variables to construct a universal, non-cooling temperature calculation model, which can dynamically adjust control parameters based on the user's actual perceived position. This makes anti-cold air control no longer limited to a fixed air outlet distance, making it particularly suitable for high-ceilinged spaces or scenarios where people's positions change, further enhancing the personalized comfort experience.

[0029] In some embodiments, the non-cooling temperature T of the indoor unit is obtained. a ,include:

[0030] A pre-established table of non-cooling temperature data is created, recording the non-cooling temperature T at various distances within a preset air outlet distance range under different outlet air temperatures and air velocities. a ;

[0031] Based on the target outlet air temperature of the indoor unit, the current outlet air speed, and the distance to the user, retrieve the corresponding non-cooling temperature T from the non-cooling temperature data table. a .

[0032] This design uses a pre-built data table and retrieves it in real time to obtain the non-cooling temperature, avoiding complex floating-point calculations during operation. This method places extremely low demands on the controller's computing power, allowing for the use of lower-cost processing chips while ensuring real-time control response.

[0033] Furthermore, based on the increase in the current inlet water temperature T1, the fan speed is increased, including:

[0034] A mapping relationship between the current inlet water temperature T1 and the fan speed is established in advance. Based on the mapping relationship, the corresponding fan speed control command is output so that the fan speed increases continuously as the current inlet water temperature T1 increases.

[0035] This design establishes a mapping relationship between inlet water temperature and fan speed, enabling continuous adjustment of fan speed as water temperature changes. This avoids airflow disturbances caused by sudden changes in speed, effectively reduces noise, and makes indoor airflow changes smoother, improving user comfort during heating.

[0036] In some embodiments, the mapping relationship between the current inlet water temperature T1 and the fan speed is as follows:

[0037] ;

[0038] Where n1 is the preset speed corresponding to the lowest fan speed, and T3 is the indoor ambient temperature.

[0039] This design uses a mapping relationship based on the square of the difference between the inlet water temperature and the target temperature. This allows the fan speed to increase gradually when the water temperature is low, preventing the outlet air temperature from dropping due to excessively rapid speed increases. Conversely, the speed increases more rapidly when the water temperature is high, shortening the time to reach the set setting. This non-linear adjustment mechanism suits the physical characteristic of water systems heating up slowly, optimizing the balance between comfort and energy efficiency.

[0040] Furthermore, methods for controlling cold air include:

[0041] Determine whether the target fan speed corresponding to the user-set temperature T2 is the preset lowest fan speed;

[0042] If so, control the indoor unit to exit anti-cold air mode;

[0043] If not, continue with the steps to increase the fan speed until the target fan speed is reached, then exit the anti-cold air mode.

[0044] This design achieves intelligent switching of control modes by determining whether the target fan speed is at its lowest setting. When the user sets the fan speed to the lowest setting, it directly exits the anti-cold air mode, simplifying the control process, reducing unnecessary logical judgments and execution actions, and helping to reduce system energy consumption.

[0045] Furthermore, the preset minimum fan speed is the lowest of the multiple preset fan speeds for the indoor unit.

[0046] This design explicitly defines the preset minimum fan speed as the lowest speed among the factory-preset multiple speeds, making the control method highly versatile and adaptable to the fan speed design specifications of different manufacturers and models of indoor units. Software-level compatibility can be achieved without modifying the hardware fan speed structure.

[0047] The present invention also proposes a water system air conditioner, including: an outdoor unit, an indoor unit, and a water pipe for transferring energy between the outdoor unit and the indoor unit, wherein the controller of the water system air conditioner is configured to perform the above-described anti-cold air control method.

[0048] This design integrates the aforementioned anti-cold air control method into the controller of the water-cooled air conditioning system, enabling the air conditioning product to possess intelligent anti-cold air capability and smooth fan speed adjustment capability during the heating start-up phase. This effectively improves the user experience of water-cooled air conditioning systems during winter heating and solves industry pain points such as slow start-up and susceptibility to cold air blowing caused by the large thermal inertia of water systems.

[0049] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0050] 1. The indoor unit's fan only starts when the inlet water temperature reaches the calculated minimum inlet water temperature. It starts at the lowest fan speed initially and then gradually increases the speed as the inlet water temperature rises. This significantly shortens the indoor unit's idle waiting time while ensuring that the blown air is not cold. Users can quickly perceive the equipment operating (a gentle breeze is blowing) after starting heating, effectively eliminating anxiety and misjudgment caused by waiting for the machine to stop. At the same time, it avoids cold air stimulation and achieves a smooth transition in the anti-cold air process.

[0051] 2. A squared mapping relationship based on the inlet water temperature is introduced to control the fan speed increase. This ensures that the fan speed increases slowly when the water temperature is low, preventing the exhaust air from becoming cold due to heat rush; and that the speed increases rapidly when the water temperature is high, quickly meeting the heating demand. This non-linear adjustment characteristic perfectly matches the physical characteristic of the water system's slow temperature rise, ensuring that the exhaust air temperature is always maintained within a comfortable range, avoiding drastic fluctuations in perceived airflow and temperature.

[0052] 3. Existing technologies often rely on fixed empirical water temperature values ​​(such as 40℃) as the fan start-up threshold, ignoring the differences in indoor ambient temperature and heat exchange efficiency. This can easily lead to "under-temperature start-up" (still blowing cold air) or "over-temperature start-up" (waiting time is too long). However, this invention introduces the concept of "no-cold-feeling temperature" and combines the jet attenuation coefficient with the heat exchanger's comprehensive efficiency coefficient to reverse-engineer the minimum inlet water temperature required for no cold-feeling under the current operating conditions. This makes the control decision more scientific and precise, ensuring both the anti-cold-feeling effect and maximizing the heating potential of the equipment. Attached Figure Description

[0053] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0054] Figure 1 This is a connection diagram of the indoor unit of the present invention;

[0055] Figure 2 This is a schematic diagram of the flow field of the indoor unit of the present invention;

[0056] Figure 3 This is a schematic diagram of the personnel activity area in a typical application scenario of the present invention;

[0057] Figure 4 This is a schematic diagram of the indoor unit in a typical application scenario of the present invention;

[0058] Figure 5 This is a flowchart illustrating the control method of the present invention;

[0059] Figure 6 This is a schematic diagram of the fan speed control process of the present invention;

[0060] Figure 7 This is a schematic diagram of the advance and retreat control process of the anti-cold air mode of the present invention;

[0061] Figure 8 This is a schematic diagram of the control flow of a preferred embodiment of the present invention;

[0062] Explanation of reference numerals in the attached figures:

[0063] 100. Indoor unit;

[0064] 101. Air vent;

[0065] 102. Return air vent;

[0066] 103. Water supply pipe;

[0067] 104. Return water pipe;

[0068] 105. Inlet water temperature sensor. Detailed Implementation

[0069] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0070] See Figures 1 to 4 As shown, the present invention proposes a method for preventing cold air from entering the room, which is applied to the indoor unit 100 of a water system air conditioner. The indoor unit 100 includes a heat exchange coil, a fan, and a water valve. The heat exchange coil is only connected to the water circuit. The inlet end of the heat exchange coil is connected to the water supply pipe 103, and the outlet end is connected to the return water pipe 104. The fan drives the air through the fins to complete the heat exchange between the water and the air.

[0071] See Figure 5 As shown, the method for controlling cold air includes the following steps:

[0072] After the indoor unit starts heating operation, the current inlet water temperature T1 and the user-set temperature T2 of the indoor unit are detected.

[0073] If the current inlet water temperature T1 is less than or equal to the user-set temperature T2, the indoor unit will be controlled to enter the anti-cold air mode, the water valve of the indoor unit will be opened and the fan will be stopped.

[0074] Calculate the minimum inlet water temperature T required for the indoor unit to produce no cooling sensation when the air is blown out. 11 ;

[0075] Monitor the current inlet water temperature T1. When the current inlet water temperature T1 reaches the minimum inlet water temperature T... 11 When the indoor unit starts running at the preset lowest fan speed, the fan speed is increased according to the increase of the current inlet water temperature T1 until the speed reaches the target fan speed corresponding to the user-set temperature.

[0076] Specifically, after the indoor unit 100 receives the heating start command, the controller of the water system air conditioner first collects the current water temperature flowing into the indoor heat exchanger—that is, the current inlet water temperature T1—through the inlet water temperature sensor 105 of the indoor unit 100. Simultaneously, it reads the target temperature set by the user via a wired controller or remote control—that is, the user-set temperature T2. In the initial stage of winter heating, because the hot water circulating in the water pipes is still being heated and transported, T1 is usually much lower than T2. ​​At this time, the controller determines that direct airflow is not currently possible, and immediately controls the water valve of the indoor unit to open to its maximum opening to accelerate the heat exchange rate. At the same time, it forcibly cuts off the power supply to the fan, keeping the cross-flow fan stationary, thereby physically preventing the possibility of low-temperature cold air being directly blown onto the user.

[0077] The system will then call a pre-stored algorithm model to calculate the minimum inlet water temperature T required for the air to feel cool. 11 During system operation, the controller continuously monitors the changing trend of the current inlet water temperature T1. As T1 gradually increases and eventually reaches the calculated minimum inlet water temperature T... 11 At this point, even a gentle breeze will be blowing, and its temperature will be higher than the human body's threshold for feeling cold. The controller will then stop the fan and instead start it at the preset lowest fan speed. The lowest speed is chosen because when the inlet water temperature has just reached the target, the system's heat exchange is not yet sufficient; a high airflow would cause a sudden drop in the outlet water temperature, potentially triggering a feeling of coldness.

[0078] While the indoor unit 100 is running at the preset lowest fan speed, the controller will collect the real-time value of the current inlet water temperature T1 at fixed intervals, filtering out instantaneous temperature jumps caused by water pipe pressure fluctuations, and ensuring the stability of temperature determination. As the water circulation continues, the current inlet water temperature T1 gradually rises. The controller will synchronously match the increase in heat supply and gradually increase the fan speed, avoiding airflow disturbances caused by sudden speed changes. In the initial stage when the current inlet water temperature T1 just exceeds the threshold, the water temperature rises slowly, and the increase in fan speed is correspondingly narrowed to avoid drawing away heat from the heat exchanger too quickly, causing the outlet air temperature to drop and resulting in a feeling of coldness. As the inlet water temperature continues to rise and the system's heat supply becomes more abundant, the increase in fan speed also increases accordingly, gradually approaching the target fan speed set by the user, until the current inlet water temperature T1 rises to a level sufficient to support the heat exchange requirements of the target fan speed. At this point, the fan speed exactly reaches the speed value corresponding to the target fan speed. Throughout the process, the air supply temperature remains stable within the comfortable range, and the user can only perceive the warm air speed gradually increasing with the rise in room temperature without experiencing any discomfort from the draft.

[0079] This design prevents the blowout of cold air by starting the fan only when the inlet water temperature reaches the calculated minimum inlet water temperature. It adopts a control logic that starts the fan at the lowest setting and then gradually increases the speed as the inlet water temperature rises, so that the air supply speed transitions smoothly with the rise of water temperature. This effectively solves the problem of user misjudgment caused by the indoor unit being shut down for a long time in the traditional anti-cold air mode, and takes into account both heating start-up speed and comfort.

[0080] In a feasible embodiment of the present invention, the minimum inlet water temperature T required to make the indoor unit's air outlet feel cool is calculated. 11 include:

[0081] Obtain the non-cooling temperature T of the indoor unit a ;

[0082] Based on the temperature T where there is no cold sensation a Based on the indoor ambient temperature T3 and the jet airflow attenuation coefficient B, the target outlet air temperature T required to be achieved at the indoor unit's outlet is calculated in reverse. 41 :

[0083] ;

[0084] The design principle of this formula is based on the isothermal free jet theory in fluid mechanics. Due to the viscosity of air, the warm air ejected from the outlet exchanges momentum and heat with the surrounding cold air during its forward transport, resulting in the actual temperature reaching the human activity area being lower than the outlet temperature. The jet attenuation coefficient B is a physical quantity used to quantify this temperature attenuation. Its value is related to the structural dimensions of the outlet and the flow field characteristics, and is usually between 1.0 and 2.0. For example, when the outlet width is 0.15m, the preferred value of B is 1.5. This formula, by introducing the value of B, represents the temperature T that the human body perceives as not feeling cold. a The reverse calculation is applied to the air outlet to ensure that the warm air remains above a comfortable threshold when it reaches the human body after experiencing temperature attenuation along the way.

[0085] Based on the target outlet air temperature T 41 Calculate the minimum inlet water temperature T based on the indoor ambient temperature T3 and the heat exchanger's overall efficiency coefficient C. 11 :

[0086] ;

[0087] This formula is designed based on the energy conservation and heat transfer efficiency logic of heat exchangers, reflecting the efficiency loss in the process of transferring heat from water to air. Due to the thermal resistance of the copper tubes and aluminum foil in the indoor heat exchanger, and limitations imposed by heat exchange time and contact area, the inlet water temperature cannot be completely and equally converted to the outlet air temperature. The overall efficiency coefficient C of the heat exchanger represents the ratio of heat absorbed by the air to heat released by the water per unit time, typically ranging from 0.6 to 0.8. This formula reveals the process of achieving the target outlet air temperature T. 41 The inlet water temperature must allow for a temperature drop margin due to insufficient heat exchange efficiency.

[0088] It should be noted that the C value is not constant. It decreases as the air velocity v of the indoor unit increases. This is because although the increased air velocity increases the convective heat transfer coefficient, it also significantly shortens the residence time of the air on the heat exchanger surface, resulting in insufficient heat exchange. Therefore, under high air velocity conditions, a higher inlet water temperature is required to achieve the same air output effect.

[0089] This design introduces a non-cooling temperature T a Using this as a control benchmark, and combining the jet blowing attenuation coefficient B with the heat exchanger's overall efficiency coefficient C, a reverse calculation can be performed to accurately quantify the minimum inlet water temperature threshold required for the air to feel cool. Compared to empirical threshold control, this calculation method fully considers the influence of ambient temperature and equipment heat exchange efficiency, improving the accuracy and reliability of anti-cold air control.

[0090] For the temperature T where there is no cooling sensation a The acquisition method can be designed according to actual usage needs. This invention provides at least three feasible solutions, which are described in detail below.

[0091] The first feasible solution.

[0092] See Figures 2 to 3 As shown, in a typical installation scenario, the indoor unit 100 has an air outlet 101 and a return air outlet 102. The ceiling height is 3 meters, and the user's typical activity area is about 1.5 meters away from the air outlet 101. There is no cooling sensation at temperature T. a Through formula calculate;

[0093] Where A is the coefficient of variation, ranging from 3 to 4, and v is the air velocity of the indoor unit, in m / s. This logarithmic relationship simulates the effect of wind speed on human body heat dissipation; the higher the wind speed, the higher the threshold for feeling no coldness.

[0094] The second feasible solution.

[0095] Temperature without cooling sensation T a Through formula calculate;

[0096] Where T is the target air outlet temperature of the indoor unit; v is the air outlet velocity of the indoor unit; and x is the distance between the user's location and the air outlet of the indoor unit. It is a positive correlation function that increases with increasing outlet air velocity; It is a negative correlation function that decreases as the distance increases.

[0097] This formula not only considers the outlet air temperature T and the air velocity v, but also incorporates the distance x between the user and the air outlet. The positive correlation function and The negative correlation function dynamically adjusts the threshold for no coldness, which is particularly useful in high-ceilinged spaces or scenarios with frequent movement of people.

[0098] In fact, this formula is a generalization of the first feasible solution, when x = 1.5m, T = 26℃, , When the value is 0, the general formula degenerates into a simplified formula for the first feasible solution.

[0099] The third feasible solution.

[0100] Obtain the non-cooling temperature T of the indoor unit a ,include:

[0101] A pre-established table of non-cooling temperature data is created, recording the non-cooling temperature T at various distances within a preset air outlet distance range under different outlet air temperatures and air velocities. a ;

[0102] In actual operation, based on the target outlet air temperature of the indoor unit, the current outlet air speed, and the distance to the user, the corresponding non-cooling temperature T is retrieved from the non-cooling temperature data table. a .

[0103] This design uses a pre-built data table and retrieves it in real time to obtain the non-cooling temperature, avoiding complex floating-point calculations during operation. This method places extremely low demands on the controller's computing power, allowing for the use of lower-cost processing chips while ensuring real-time control response.

[0104] To facilitate understanding, let's illustrate with specific numerical examples. When the indoor ambient temperature T3 is 10℃, the width of the indoor unit's air outlet is 0.15m (i.e., B is taken as 1.5), and there is no cooling sensation at temperature T. a Through formula Calculate the temperature T at 1.5 meters where A is 3.5. a As shown in Table 1 below:

[0105] 1.0m / s 26℃ 1.2m / s 26.6℃ 1.5m / s 27.4℃ 2.0m / s 28.4℃

[0106] Table 1

[0107] The indoor unit's fan has three speed settings: 1.0 m / s, 1.5 m / s, and 2.0 m / s, corresponding to a target outlet air temperature T. 41 As shown in Table 2 below:

[0108] 1.0m / s 34℃ 1.5m / s 36.1℃ 2.0m / s 37.6℃

[0109] Table 2

[0110] Based on this, when the target outlet air temperature T 41 When the temperature is 34℃ and C is 0.8, substitute into the formula. The calculated minimum inlet water temperature T 11 The temperature is 40℃.

[0111] See Figure 6 As shown, to improve user comfort, in some embodiments of the present invention, the fan speed is increased according to the increase in the current inlet water temperature T1, including:

[0112] A mapping relationship between the current inlet water temperature T1 and the fan speed is pre-established. During operation, the controller outputs the corresponding fan speed control command according to the mapping relationship, so that the fan speed increases continuously as the current inlet water temperature T1 rises. There will be no sudden increase or decrease in air volume throughout the process. Users can only perceive that the warm air speed increases evenly as the room temperature rises. This avoids sudden changes in airflow noise caused by speed jumps and also prevents fluctuations in outlet air temperature caused by a sudden increase in air volume drawing away heat from the heat exchanger, thus maintaining a gentle air delivery.

[0113] Based on this, the preferred solution is the mapping relationship between the current inlet water temperature T1 and the fan speed as follows:

[0114] ;

[0115] Where n1 is the preset speed corresponding to the lowest fan speed, and T3 is the indoor ambient temperature.

[0116] This nonlinear adjustment method has unique adaptability, and it works when T1 is slightly higher than T. 11 In the initial stage, the difference between the numerator and denominator is small, and the squaring operation makes the speed increase extremely gradual, effectively preventing the outlet air temperature from dropping due to heat grabbing; however, when T1 is much higher than T... 11 When the system has sufficient heat, the square effect causes the rotational speed to increase rapidly. When the detection and calculation are performed in 1-second intervals, the indoor unit fan speed will steadily increase, thereby achieving stepless speed regulation of the fan.

[0117] To facilitate understanding, specific numerical examples are used. When the indoor unit starts operating at the preset lowest fan speed, the current inlet water temperature T1 is 40℃, the corresponding fan speed is 500 rpm, and the indoor ambient temperature T3 is 10℃. The fan speed changes as T1 increases to 42℃, 45℃, and 50℃, as shown in Table 3 below.

[0118] 42℃ 568.8 45℃ 680.5 50℃ 888.8

[0119] Table 3

[0120] Theoretical data shows that when the inlet water temperature is 42℃, the fan speed can be maintained at 568.8 rpm; when the inlet water temperature rises to 45℃, the speed smoothly transitions to 680.5 rpm; when the inlet water temperature reaches 50℃, the speed can be rapidly increased to 888.8 rpm. This incremental acceleration curve perfectly matches the characteristics of water system with large thermal inertia and slow temperature rise.

[0121] In actual operation, as the current inlet water temperature T1 increases, the indoor ambient temperature T3 will also increase synchronously, but its rate of increase is much smaller than the rate of increase of the current inlet water temperature T1. Assuming that the indoor ambient temperature T3 increases to 12℃, 13℃, and 15℃ respectively, the changes in fan speed are shown in Table 4 below:

[0122] 42℃ 11℃ 571.3 45℃ 12℃ 694.5 50℃ 13℃ 938.9

[0123] Table 4

[0124] The above measured data shows that when the inlet water temperature is 42℃, the fan speed remains stable at around 571.3 rpm, only slightly higher than the lowest setting's base speed. As the water circulation progresses and the inlet water temperature gradually rises to 45℃, the temperature difference ratio increases, and the speed smoothly transitions to 694.5 rpm. When the inlet water temperature reaches 50℃ and the system's heat supply is sufficient, the square gain effect drives the speed to rapidly increase to 938.9 rpm, significantly shortening the waiting time to reach the user-set setting. The entire upgrade process is a continuous stepless adjustment, without any abrupt changes in fan speed. Users only perceive a slow increase in warm air speed as the room temperature rises, without ever experiencing a cooling sensation.

[0125] See Figure 7 As shown, to further enhance the intelligence of control, the system, while executing the acceleration process, will also determine in real time whether the target fan speed corresponding to the user-set temperature T2 is the preset minimum fan speed. If the user originally set it to a low fan speed—the preset minimum fan speed—then when the water temperature reaches the target—the current inlet water temperature T1 reaches the minimum inlet water temperature T... 11Afterward, the system will directly exit the anti-cold air mode and maintain the current low fan speed operation, eliminating the need for complex speed-up calculations, thus simplifying the control process and reducing power consumption. Conversely, if the target fan speed is a higher level, the fan speed will be increased according to the rise in the current inlet water temperature T1, smoothly transitioning the speed from the lowest level to the target level. This avoids airflow disturbances caused by sudden speed changes, effectively reducing noise and making the indoor airflow changes more gentle, improving user comfort during the heating process.

[0126] In some embodiments of the present invention, the preset minimum fan speed is the lowest speed among the multiple preset operating fan speeds of the indoor unit. By explicitly defining the preset minimum fan speed as the lowest speed among the multiple preset speeds, the control method has good universality and can be adapted to the fan speed design specifications of different manufacturers and different models of indoor units. Software-level compatibility can be achieved without modifying the hardware fan speed structure.

[0127] See Figure 8 As shown, for ease of understanding, the flow of the anti-cold air control method of the present invention is as follows:

[0128] After the indoor unit starts heating operation, the current inlet water temperature T1 and the user-set temperature T2 of the indoor unit are detected.

[0129] If the current inlet water temperature T1 is less than or equal to the user-set temperature T2, the indoor unit will be controlled to enter the anti-cold air mode, the water valve of the indoor unit will be opened and the fan will be stopped.

[0130] Calculate the minimum inlet water temperature T required for the indoor unit to produce no cooling sensation when the air is blown out. 11 ;

[0131] Monitor the current inlet water temperature T1. When the current inlet water temperature T1 reaches the minimum inlet water temperature T... 11 At this time, the indoor unit will start running at the preset lowest fan speed;

[0132] Determine whether the target fan speed corresponding to the user-set temperature T2 is the preset lowest fan speed;

[0133] If so, control the indoor unit to exit anti-cold air mode;

[0134] If not, while the indoor unit is running at the preset lowest operating fan speed, the fan speed will be increased according to the rise in the current inlet water temperature T1 until the speed reaches the target fan speed corresponding to the user-set temperature, and then the anti-cold air mode will be exited.

[0135] This invention not only solves the problems of slow start-up and cold air blowing in water-based air conditioning systems, but also significantly improves the user's winter heating experience through smooth wind speed control and intelligent mode switching.

[0136] See Figure 1As shown, the water-based air conditioning system proposed in this invention includes, but is not limited to, a water-based central air conditioning system. A water-based air conditioning system typically consists of an outdoor unit, indoor units, and water pipes connecting the two. The outdoor unit includes core refrigeration components such as a compressor, condenser, evaporator, throttling element, and four-way reversing valve. Only the refrigerant circulates within the outdoor unit to complete heat exchange, without direct connection to the indoor unit. The water pipes include a circulating water pump and insulated water pipes, responsible for connecting the outdoor unit and each indoor unit, forming a closed hydraulic circulation path. The indoor unit 100 includes a heat exchange coil, fan, and water valve. The heat exchange coil is only connected to the water circuit, and the fan drives air through the fins to complete heat exchange between water and air. The entire system uses water as a secondary energy distribution medium, unlike the refrigerant system which directly delivers refrigerant to the indoor unit.

[0137] In heating mode, the four-way reversing valve switches the refrigerant flow direction. The evaporator of the outdoor unit absorbs heat from the low-temperature air, which is then compressed into a high-temperature, high-pressure gaseous refrigerant by the compressor and enters the condenser. It releases heat to the circulating water in the water pipe, raising the supply water temperature. The circulating water pump then drives the water to be delivered to each of the open indoor units 100 along the water supply pipe 103. After the water valve is opened, the high-temperature hot water flows through the indoor heat exchange coil. The heat is transferred to the indoor air through the pipe wall and fins. The cooled return water returns to the outdoor unit along the return water pipe 104 for reheating. A certain temperature difference is formed between the supply and return water, corresponding to the total heat extracted from the water by the indoor terminals. The entire hydraulic circulation is independent of the refrigerant circulation. The opening and closing of the water valve of a single indoor unit 100 only controls the on / off of the corresponding branch and does not affect the operation of other terminals and the outdoor unit.

[0138] Water-cooled air conditioning systems operate based on the reverse Carnot cycle and convective heat transfer principle. During heating, the outdoor unit transfers low-grade heat energy from the outdoor air to the water through the heat pump effect. Water has a high specific heat capacity, and the system piping has a large water storage capacity, resulting in significant thermal inertia during the heating process. It takes some time for the water temperature to climb after startup. If the fan is started immediately upon startup, forced convection when the coil temperature approaches room temperature will accelerate heat dissipation from the body, leading to a feeling of cold air. The indoor unit's airflow follows a non-isothermal free jet principle; when the high-temperature airflow from the outlet is forward... It mixes with the surrounding cold air, and the temperature drops significantly when it reaches the area where people are active. Therefore, a higher outlet air temperature is needed to offset the jet loss. At the same time, the efficiency of the heat exchange coil is affected by the wind speed. Although the high wind speed increases the convective heat transfer coefficient, it will shorten the residence time of the air on the coil surface, resulting in insufficient heat exchange. The control logic of the whole system needs to match the characteristics of the large thermal inertia of water. In the early stage of heating, the air volume is limited to avoid a sudden drop in outlet air temperature. After the water temperature is sufficient, the speed is gradually increased to achieve a balance between temperature stability and comfortable air supply.

[0139] This invention utilizes the aforementioned cold air prevention control method to activate the indoor unit's fan only when the inlet water temperature reaches the calculated minimum inlet water temperature. It initially starts at the lowest fan speed and then gradually increases the speed as the inlet water temperature rises. This significantly shortens the indoor unit's idle waiting time while ensuring the blown air is not cold. Users can quickly perceive the equipment operating (a gentle breeze) after starting heating, effectively eliminating anxiety and misjudgment caused by waiting during shutdown, while also avoiding cold air stimulation and achieving a smooth transition in the cold air prevention process.

[0140] Furthermore, by introducing the concept of "no-cooling temperature" and combining the jet attenuation coefficient with the heat exchanger's overall efficiency coefficient, the minimum inlet water temperature required for no cooling under the current operating conditions can be accurately calculated in reverse. This makes the control decision more scientific and precise, ensuring both the anti-cold air effect and maximizing the heating potential of the equipment.

[0141] Furthermore, by introducing a squared mapping relationship based on the inlet water temperature to control the fan speed increase, the fan speed increases slowly when the water temperature is low to prevent the exhaust air from becoming cold due to heat rush; when the water temperature is high, the speed increases rapidly to quickly meet the heating demand. This non-linear adjustment characteristic perfectly matches the physical characteristic of the water system's slow temperature rise, ensuring that the exhaust air temperature is always maintained within a comfortable range and avoiding drastic fluctuations in the perceived airflow and temperature.

[0142] Based on the above control logic, the water system air conditioning product can quickly enter the low-wind heating state when starting heating in winter, and naturally transition to the user-set comfort level as the water temperature rises, completely changing the traditional impression of water heaters as "slow to start, long waiting time, and cold air".

[0143] In the preferred embodiment, the indoor unit is equipped with a controller, temperature sensor, and fan speed detection module. When the controller executes the aforementioned anti-cold air control logic, it can independently decide the start / stop and speed of the indoor unit's fan based on the actual physical state of the inlet water temperature, without frequently requesting the outdoor unit to change its operating frequency or adjust the water pump speed. This ensures that the anti-cold air action of a single indoor unit does not affect other normally operating indoor units in the same system, nor does it increase the ineffective energy consumption of the outdoor unit, thereby achieving optimal energy efficiency at the entire water system level.

[0144] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments of the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings may be implemented in any order unless a specific express order is specified, and as long as the output of a previous process is not used in a subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0145] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as constraints. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0146] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preventing cold air from entering the air conditioner, applied to the indoor unit of a water-cooled air conditioning system, characterized in that: Includes the following steps: After the indoor unit starts heating operation, the current inlet water temperature T1 and the user-set temperature T2 of the indoor unit are detected. If the current inlet water temperature T1 is less than or equal to the user-set temperature T2, then the indoor unit is controlled to enter the anti-cold air mode, the water valve of the indoor unit is opened and the fan is stopped. Calculate the minimum inlet water temperature T required to make the indoor unit's airflow feel cool. 11 ; Monitor the current inlet water temperature T1, and when the current inlet water temperature T1 reaches the minimum inlet water temperature T... 11 When the indoor unit's fan starts running at the preset lowest fan speed, the fan speed is increased according to the increase in the current inlet water temperature T1 until the fan speed reaches the target fan speed corresponding to the user-set temperature. Calculate the minimum inlet water temperature T required to make the indoor unit's airflow feel cool. 11 include: Obtain the non-cooling temperature T of the indoor unit. a ; According to the aforementioned non-cooling temperature T a Based on the indoor ambient temperature T3 and the jet airflow attenuation coefficient B, the target outlet air temperature T required to be achieved at the indoor unit's outlet is calculated in reverse. 41 : ； According to the target outlet air temperature T 41 Calculate the minimum inlet water temperature T based on the indoor ambient temperature T3 and the heat exchanger's overall efficiency coefficient C. 11 : ； The jet air attenuation coefficient B ranges from 1.0 to 2.0, the heat exchanger comprehensive efficiency coefficient C ranges from 0.6 to 0.8, and the heat exchanger comprehensive efficiency coefficient C decreases as the air outlet velocity v of the indoor unit increases.

2. The method for controlling cold air according to claim 1, characterized in that, In an application scenario where the indoor unit is installed at a height of 3 meters and the air outlet distance is 1.5 meters, the non-cooling temperature T a Through formula calculate; Where A is the variation coefficient, with a value ranging from 3 to 4, and v is the air outlet speed of the indoor unit.

3. The method for controlling cold air according to claim 1, characterized in that, The temperature T that does not feel cold a Through formula calculate; Where T is the target air outlet temperature of the indoor unit; v is the air outlet velocity of the indoor unit; and x is the distance between the user's location and the air outlet of the indoor unit. This is a positive correlation function that increases with the increase of the outlet air velocity; This is a negative correlation function that decreases as the distance increases.

4. The method for controlling cold air according to claim 1, characterized in that, Obtain the non-cooling temperature T of the indoor unit. a ,include: A pre-established non-cooling temperature data table records the non-cooling temperature T corresponding to each distance point within a preset air outlet distance range under different outlet air temperatures and different outlet air velocities. a ; Based on the target air outlet temperature of the indoor unit, the current air outlet speed, and the distance to the user, the corresponding non-cooling temperature T is retrieved from the non-cooling temperature data table. a .

5. A method for preventing cold air from entering the air conditioner, applied to the indoor unit of a water-cooled air conditioning system, characterized in that: Includes the following steps: After the indoor unit starts heating operation, the current inlet water temperature T1 and the user-set temperature T2 of the indoor unit are detected. If the current inlet water temperature T1 is less than or equal to the user-set temperature T2, then the indoor unit is controlled to enter the anti-cold air mode, the water valve of the indoor unit is opened and the fan is stopped. Calculate the minimum inlet water temperature T required to make the indoor unit's airflow feel cool. 11 ; Monitor the current inlet water temperature T1, and when the current inlet water temperature T1 reaches the minimum inlet water temperature T... 11 When the indoor unit's fan starts running at the preset lowest fan speed, the fan speed is increased according to the increase in the current inlet water temperature T1 until the fan speed reaches the target fan speed corresponding to the user-set temperature. Increasing the fan speed based on the increase in the current inlet water temperature T1 includes: A mapping relationship between the current inlet water temperature T1 and the fan speed is established in advance. Based on the mapping relationship, a corresponding fan speed control command is output so that the fan speed continuously increases as the current inlet water temperature T1 increases. The mapping relationship between the current inlet water temperature T1 and the fan speed is as follows: ； Where n1 is the preset speed corresponding to the lowest fan speed, and T3 is the indoor ambient temperature.

6. The method for controlling cold air according to claim 1, characterized in that, Also includes: Determine whether the target fan speed corresponding to the user-set temperature T2 is the preset lowest fan speed; If so, control the indoor unit to exit the anti-cold air mode; If not, continue to increase the fan speed until the target fan speed is reached, and then exit the anti-cold air mode.

7. The method for controlling cold air according to any one of claims 1 to 6, characterized in that, The preset minimum fan speed is the lowest speed among the multiple preset operating fan speeds of the indoor unit.

8. Water-based air conditioning system, including: An outdoor unit, an indoor unit, and a water pipe for transferring energy between the outdoor unit and the indoor unit, characterized in that the controller of the water system air conditioner is configured to perform the anti-cold air control method according to any one of claims 1 to 7.

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