Radiation air conditioning dehumidification fresh air machine variable air supply target control method

Abstract

The present application relates to the field of radiation air conditioning technology, and more particularly to a radiation air conditioner dehumidification fresh air machine variable air supply target control method, comprising collecting indoor dew point temperature, outdoor environment temperature, actual air supply dew point temperature and air supply temperature; setting a target dew point temperature, calculating a dew point temperature deviation; according to the range of the dew point temperature deviation, obtaining different reference target air supply dew point temperatures; correcting the reference target air supply dew point temperature; according to the difference between the current actual air supply dew point temperature and the corrected reference target air supply dew point temperature, adjusting the operating frequency of the compressor of the fresh air dehumidifier to meet the dehumidification demand. The present application solves the defects of slow dehumidification replacement in the starting stage, excessive dehumidification in the low load working condition and unintelligent reheat air supply temperature regulation and control caused by the single dehumidification fresh air strategy of the existing radiation system.

Description

Technical Field

[0001] This invention relates to the field of radiant air conditioning technology, and in particular to a method for controlling the variable air supply target of a radiant air conditioning dehumidifier fresh air unit. Background Technology

[0002] Radiant air conditioning systems are comfort air conditioning systems with independent temperature and humidity control. In this system, the fresh air dehumidifier plays a key role in dehumidification and fresh air replacement. During summer operation, the indoor air dew point temperature must be lowered by using dehumidified fresh air so that the water temperature of the radiant system can be further lowered to achieve the effect of radiant cooling.

[0003] Currently, radiant air conditioning systems mostly use constant supply air control for fresh air dehumidification. This means that when the system is first turned on, the indoor humidity is high (high dew point temperature) or the indoor dew point is low, a relatively constant supply air temperature and dew point temperature are used, without any obvious intelligent control strategy. Therefore, in the hot and humid summer, when the system starts up, the indoor humidity often decreases slowly because the supply air dew point temperature is relatively high, which in turn limits the reduction of the system's radiant water temperature, making it difficult for the indoor temperature to quickly reach the set value. In addition, under low load conditions, a constant dew point temperature can easily lead to over-dehumidification, which not only affects indoor comfort but also causes energy waste. Summary of the Invention

[0004] To address the shortcomings of existing methods, this invention solves the problems of slow dehumidification and replacement during startup, excessive dehumidification under low load conditions, and unintelligent reheat supply air temperature control caused by the single dehumidification fresh air strategy of existing radiant systems.

[0005] The technical solution adopted in this invention is: a method for controlling the target air supply of a radiant air conditioning dehumidifier fresh air unit, comprising the following steps: Step 1: Collect indoor dew point temperature Tdi, outdoor ambient temperature Tout, actual supply air dew point temperature Tdo, and supply air temperature To; Step 2: Calculate the user-defined target dew point temperature Tdset and the dew point temperature deviation ΔTd; Dew point temperature deviation ΔTd = Current indoor average dew point temperature Tdi_avg - Target dew point temperature Tdset.

[0006] Step 3: Based on the range of dew point temperature deviation ΔTd, obtain different reference target supply air dew point temperatures Tdo_base; correct the reference target supply air dew point temperature to obtain the corrected reference target supply air dew point temperature Tdo_target; In a preferred embodiment of the present invention, the benchmark target supply air dew point temperature includes: When ΔTd ≤ the over-dehumidification risk threshold C, Tdo_base = Tdo_base_max = Tdset + ΔTd_adj; Tdo_base_max is the upper limit of the supply air dew point temperature, and ΔTd_adj is the dew point temperature correction value to prevent over-dehumidification. When C < ΔTd ≤ high load threshold A, Tdo_base = Tdo_base_min + (ΔTd - A) × (Tdo_base_max - Tdo_base_min) / (CA); Tdo_base_min is the lower limit of the supply air dew point temperature; When ΔTd>A, Tdo_base=Tdo_base_min.

[0007] In a preferred embodiment of the present invention, the formula for correcting the reference target supply air dew point temperature is as follows: Tdo_target=Tdo_base×N_Tout; N_Tout is the correction factor.

[0008] In a preferred embodiment of the present invention, when N_Tout ≤ the lower limit threshold of outdoor ambient temperature T1, N_Tout = the upper limit threshold of correction coefficient N1; when T1 < Tout ≤ the upper limit threshold of outdoor ambient temperature T2, N_Tout = N1 + (Tout - T1) × (N2 - N1) / (T2 - T1); when N_Tout > T2, N_Tout = the lower limit threshold of correction coefficient N2.

[0009] Step 4: Adjust the operating frequency of the compressor of the fresh air dehumidifier based on the difference between the current actual supply air dew point temperature and the corrected benchmark target supply air dew point temperature, i.e., the supply air dew point temperature deviation ΔTdo. In a preferred embodiment of the present invention, the operating frequency adjustment includes: ΔTdo = Tdo - Tdo_target; When ΔTdo > the upper limit threshold of the supply air dew point temperature deviation, increase the compressor frequency F; When the lower threshold of the supply air dew point temperature deviation is ≤ ΔTdo ≤ the upper threshold of the supply air dew point temperature deviation, the compressor frequency is finely adjusted. When ΔTdo < the lower limit threshold of the supply air dew point temperature deviation, reduce the compressor frequency.

[0010] In a preferred embodiment of the present invention, while adjusting the compressor operating frequency, the target reheat air temperature is obtained, and the temperature of the fresh air supplied to the room is adjusted.

[0011] In a preferred embodiment of the present invention, the formula for the target reheat supply air temperature is: To_target=max(To_base, To_min_safe); Where To_base is the baseline target reheat supply air temperature, and To_min_safe is the lower limit of the anti-condensation safety target reheat supply air temperature.

[0012] In a preferred embodiment of the present invention, To_base is determined based on Tout and the user-set minimum temperature value Tset_min, according to an energy-saving and comfort control strategy.

[0013] In a preferred embodiment of the present invention, the formula for the lower limit of the anti-condensation safety target reheat supply air temperature is as follows: To_min_safe=Tdi_avg + ΔT_safe - ΔT_pipe; Where ΔT_pipe is the temperature rise from the fresh air unit outlet to the indoor air supply outlet, and ΔT_safe is the safety margin for preventing condensation.

[0014] In a preferred embodiment of the present invention, the opening degree of the reheat electronic expansion valve is adjusted according to the difference between To and To_target.

[0015] The beneficial effects of this invention are: 1. The present invention provides a target control method for the supply air of a radiant air conditioning dehumidifier fresh air unit. Based on the difference between the actual indoor dew point temperature and the user-set dew point temperature, the target dew point supply air temperature of the fresh air dehumidifier is dynamically adjusted through a centralized control gateway (and corrected according to the outdoor ambient temperature). When the unit is turned on in high humidity conditions in summer, the supply air with a lower dew point temperature can quickly replace and dehumidify the air, prompting the radiant system to respond quickly and improve the cooling efficiency. 2. When the indoor dew point reaches equilibrium or is low, the supply air dew point temperature is automatically adjusted to effectively avoid excessive dehumidification and ensure stable and comfortable indoor humidity. 3. The dynamic reheat air supply strategy takes into account the user's cooling needs, air supply comfort, and anti-condensation safety, further improving the overall performance of the radiant air conditioning system. Attached Figure Description

[0016] Figure 1 This is a flowchart of the target control method for the radiant air conditioning dehumidification fresh air unit of the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. The drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0018] like Figure 1As shown, a method for controlling the air supply target of a radiant air conditioning dehumidifier fresh air unit includes the following steps: Radiant terminal: Installed indoors, responsible for handling the sensible heat load and regulating the temperature; Fresh air dehumidification unit: integrates refrigeration compressor, reheat module and electronic expansion valve, responsible for handling fresh air load and indoor latent heat load; Sensing system: including an indoor dew point thermostat to monitor the dew point temperature Tdi in each area; an outdoor temperature sensor to monitor the ambient temperature Tout; and a temperature and humidity sensor installed in the fan supply section to monitor the actual supply air dew point temperature Tdo and supply air temperature To.

[0019] Step 1: System startup and parameter monitoring; When the radiant air conditioning system starts its cooling and dehumidification operation mode, it executes an integrated intelligent air supply strategy. The system first initializes all sensors, and then collects the following key parameters in real time as control inputs: Dew point temperatures in different areas of the room: Tdi1=19.5℃, Tdi2=19.8℃, Tdi3=20.1℃; The area is determined based on the number of rooms; in this embodiment, it is 3. Outdoor ambient temperature: Tout = 32℃; User-defined indoor parameters: Temperature Tset=26℃, Relative humidity RHset=50%; Step 2: Calculate the user-defined target dew point temperature Tdset and the dew point temperature deviation ΔTd; Based on the user-defined temperature and humidity (Tset=26℃, RHset=50%), the corresponding target dew point temperature Tdset=14.8℃ is calculated using a lookup table or formula. Calculate the current indoor average dew point temperature: Tdi_avg = (19.5+19.8+20.1) / 3 = 19.8℃; Calculate the dew point temperature deviation: ΔTd = Tdi_avg-Tdset = 19.8 -14.8 = +5.0℃. ΔTd is the core indicator for judging the indoor humidity load status (such as starting high humidity, normal load, and risk of excessive dehumidification). Step 3: Based on the range of dew point temperature deviation, obtain different reference target supply air dew point temperatures Tdo_base; correct the reference target supply air dew point temperatures to obtain Tdo_target; Step 31: Determine the baseline target supply air dew point temperature Tdo_base; Based on the dew point temperature difference ΔTd, the three-stage control strategy shown in Table 1 is used to determine Tdo_base; Preset parameters: high load threshold A = 10°C, excessive dehumidification risk threshold C = -2°C, lower limit of supply air dew point temperature Tdo_base_min = 7°C; upper limit of supply air dew point temperature Tdo_base_max = Tdset + ΔTd_adj. In this embodiment, ΔTd_adj = 1°C. Therefore, Tdo_base_max = 14.8 + 1 = 15.8°C.

[0020] Currently, ΔTd = +5.0°C. The system determines that C < ΔTd ≤ A. According to the preset strategy, based on linear interpolation calculation: Tdo_base = Tdo_base_min + (ΔTd - A) × (Tdo_base_max - Tdo_base_min) / (C - A) = 7 + (5 - 10) × (15.8 - 7) / (-2 - 10) = 10.7°C.

[0021] Table 1 Strategy for determining the reference target supply air dew point temperature based on ΔTd

[0022] Step 32: Correct the outdoor ambient temperature to obtain the corrected reference target supply air dew point temperature Tdo_target; Correct Tdo_base according to the outdoor ambient temperature Tout: Tdo_target = Tdo_base × N_Tout, where the correction coefficient N_Tout is determined by the three-segment control strategy shown in Table 2; For example, currently Tout = 32°C. The system determines that the lower threshold of the outdoor ambient temperature T1 < Tout ≤ the upper threshold of the outdoor ambient temperature T2. According to the preset strategy, based on linear interpolation calculation: N_Tout = N1 + (Tout - T1) × (N2 - N1) / (T2 - T1) = 1.3 + (32 - 25) × (0.7 - 1.3) / (45 - 25) = 1.09; Therefore, Tdo_target = 10.7 × 1.09 = 11.7°C ≈ 12°C, which is approximately 3°C lower than the target dew point Tdset to accelerate indoor dehumidification.

[0023] Table 2 Strategy for determining the correction coefficient based on the outdoor temperature

[0024] Step Four: Adjust the compressor frequency to achieve the supply air dew point target; The compressor of the fresh air dehumidifier dynamically adjusts its operating frequency F based on the deviation between the current actual supply air dew point temperature Tdo and the target value Tdo_target, i.e., ΔTdo = Tdo - Tdo_target. When ΔTdo > the upper limit threshold of the supply air dew point temperature deviation of 0.5℃, it indicates that the current dehumidification capacity is insufficient. The compressor frequency should be increased significantly to enhance the dehumidification effect. When the lower limit threshold of the supply air dew point temperature deviation is -0.5℃ ≤ ΔTdo ≤ 0.5℃, the fine-tuning mode is adopted; When ΔTdo < -0.5℃, it indicates excessive dehumidification. Reduce the compressor frequency to save energy and prevent excessive dehumidification. For example, if Tdo is measured to be 18℃ at the beginning of system operation, and ΔTdo is calculated to be 18-12=6℃ > 0.5℃, the control system sends a command to the compressor of the fresh air dehumidifier to increase the operating frequency F, thereby further reducing the supply air dew point temperature. The system continuously monitors ΔTdo and dynamically adjusts the compressor frequency until Tdo approaches the target value of 12℃.

[0025] Step 5: Intelligently set the target reheat supply air temperature; To ensure comfortable airflow and prevent condensation at the radiant heating terminals, the dehumidified, low-temperature air needs to be reheated before being introduced into the room, and a target temperature To_target needs to be intelligently set. Step 51: Determine the baseline target reheat supply air temperature To_base; Based on the outdoor temperature Tout and the user-set minimum temperature value Tset_min, the values ​​are determined according to Table 3 based on the energy-saving and comfort control strategy. In this embodiment, Tout=32℃, Tset_min=26℃, and according to the control strategy in Table 3, To_base=14℃; Table 3 Control strategy for baseline target reheat supply air temperature

[0026] Step 52: Calculate the lower limit of the anti-condensation safety target reheat supply air temperature, To_min_safe; Real-time acquisition of Tdi_avg (19.8℃); setting an anti-condensation safety margin ΔT_safe, 1℃; and considering the temperature rise ΔT_pipe, 3℃, from the fresh air unit outlet to the indoor air supply outlet; calculating the lower limit of the anti-condensation safety target reheat supply air temperature: To_min_safe=Tdi_avg + ΔT_safe - ΔT_pipe=19.8+1-3=17.8℃; Step 53: Determine the final target reheat supply air temperature To_target; The final target reheat supply air temperature To_targe = max( To_base, To_min_safe ) = (14℃, 17.8℃ ) = 17.8℃≈18℃; Reheating does not involve heating the indoor air; it involves adjusting the supply air temperature, intelligently changing the supply air temperature according to conditions.

[0027] This step ensures that the supply air temperature meets energy-saving requirements while absolutely satisfying the safety constraints of preventing condensation.

[0028] Step 6: Adjust the opening of the reheat electronic expansion valve; The reheat electronic expansion valve of the fresh air dehumidifier dynamically adjusts its opening based on the deviation between the current actual supply air temperature To and the target value To_target, i.e., ΔTo = To - To_target. Specifically: When ΔTo < -1℃, it indicates that the supply air temperature is too low. Increase the opening to increase the reheat. When -1℃ ≤ ΔTo ≤ 1℃, maintain the current opening degree; When ΔTo > 1℃, it indicates that the supply air temperature is too high. Reduce the opening to reduce the reheat. For example, if the current To = 20℃, then ΔTo = 20 - 18 = 2℃ > 1℃. The control system sends a command to the reheat electronic expansion valve of the fresh air dehumidifier to reduce its opening and reduce the amount of reheat. The system continuously monitors ΔTo and dynamically adjusts the opening of the electronic expansion valve until To stabilizes at around 18℃. Implementation results: Start-up phase: By setting a low Tdo_target (12℃), the fresh air dehumidifier operates with high dehumidification capacity, quickly delivering dry fresh air into the room to replace the humid air, causing the indoor average dew point Tdi_avg to drop rapidly from 19.8℃; Load change adaptation: When ΔTd decreases, the control algorithm automatically increases Tdo_base and combines it with outdoor temperature correction to reduce the cooling and dehumidification intensity of the compressor, avoiding energy waste and excessively dry air caused by continuous deep dehumidification under low load conditions, thus achieving "on-demand dehumidification". Precise reheat control: The setting of the reheat target temperature To_target integrates the energy-saving baseline value (To_base) based on outdoor conditions and the anti-condensation safety lower limit (To_min_safe) based on the actual indoor dew point. In this embodiment, the safety lower limit (17.8℃) takes precedence, ensuring that the supply air temperature is higher than the condensation risk point under any circumstances, while avoiding the increase in reheat energy consumption caused by blindly increasing the temperature to prevent condensation.

[0029] The entire process achieves dynamic and coordinated optimization of supply air dew point temperature and reheat supply air temperature, which improves the system's adaptability to different operating conditions and overall energy efficiency while ensuring dehumidification effect and comfort.

[0030] This invention's intelligent air supply control strategy can dynamically adjust air supply parameters according to system load changes, effectively improving the comfort and energy efficiency of the radiant air conditioning system. During the high-load start-up phase, by controlling a lower air supply dew point temperature, the indoor air exchange and dehumidification process is accelerated, thereby allowing the radiant water temperature to drop rapidly and achieving a more rapid cooling effect. Under steady-state or low-load conditions, the compressor frequency of the fresh air unit is intelligently adjusted to regulate the air supply dew point temperature, ensuring indoor humidity balance, avoiding excessive dehumidification, and keeping the system in a more energy-efficient and comfortable operating state. In addition, by combining the indoor set temperature, outdoor ambient temperature, and the lower limit of the anti-condensation safety temperature, the air supply temperature after reheating is dynamically optimized, ensuring that the air supply temperature meets energy-saving requirements while absolutely meeting the safety constraints of anti-condensation.

[0031] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for controlling the air supply target of a radiant air conditioning dehumidifier fresh air unit, characterized in that, Includes the following steps: Step 1: Collect indoor dew point temperature Tdi, outdoor ambient temperature Tout, actual supply air dew point temperature Tdo, and supply air temperature To; Step 2: Calculate the user-defined target dew point temperature Tdset and the dew point temperature deviation ΔTd; Step 3: Based on the range of dew point temperature deviation ΔTd, obtain different reference target supply air dew point temperatures Tdo_base; The baseline target supply air dew point temperature is corrected to obtain the corrected baseline target supply air dew point temperature Tdo_target; Step 4: Adjust the operating frequency of the compressor of the fresh air dehumidifier based on the difference between the current actual supply air dew point temperature and the corrected benchmark supply air dew point temperature.

2. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 1, characterized in that, The baseline target supply air dew point temperature includes: When ΔTd ≤ the over-dehumidification risk threshold C, Tdo_base = Tdo_base_max = Tdset + ΔTd_adj; Tdo_base_max is the upper limit of the supply air dew point temperature, and ΔTd_adj is the dew point temperature correction value to prevent over-dehumidification. When C < ΔTd ≤ high load threshold A, Tdo_base = Tdo_base_min + (ΔTd - A) × (Tdo_base_max - Tdo_base_min) / (CA); Tdo_base_min is the lower limit of the supply air dew point temperature; When ΔTd>A, Tdo_base=Tdo_base_min.

3. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 2, characterized in that, The formula for correcting the target supply air dew point temperature is: Tdo_target=Tdo_base×N_Tout; N_Tout is the correction factor.

4. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 3, characterized in that, When N_Tout ≤ the lower limit threshold of outdoor ambient temperature T1, N_Tout = the upper limit threshold of correction coefficient N1; when T1 < Tout ≤ the upper limit threshold of outdoor ambient temperature T2, N_Tout = N1 + (Tout - T1) × (N2 - N1) / (T2 - T1); when N_Tout > T2, N_Tout = the lower limit threshold of correction coefficient N2.

5. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to any one of claims 2 and 3, characterized in that, Operating frequency adjustment includes: ΔTdo = Tdo - Tdo_target; When ΔTdo > the upper limit threshold of the supply air dew point temperature deviation, increase the compressor frequency F; When the lower threshold of the supply air dew point temperature deviation is ≤ ΔTdo ≤ the upper threshold of the supply air dew point temperature deviation, the compressor frequency is finely adjusted. When ΔTdo < the lower limit threshold of the supply air dew point temperature deviation, reduce the compressor frequency.

6. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 5, characterized in that, While adjusting the compressor's operating frequency, the target reheat supply air temperature is obtained, and the temperature of the fresh air supplied to the room is adjusted.

7. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 6, characterized in that, The formula for the target reheat supply air temperature is: To_target=max(To_base, To_min_safe); Where To_base is the baseline target reheat supply air temperature, and To_min_safe is the lower limit of the anti-condensation safe target reheat supply air temperature.

8. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 7, characterized in that, To_base is determined based on Tout and the user-defined minimum temperature value Tset_min, according to the energy-saving and comfort control strategy.

9. The method for controlling the air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 7, characterized in that, The formula for the lower limit of the anti-condensation safety target reheat supply air temperature is: To_min_safe=Tdi_avg + ΔT_safe - ΔT_pipe; Where Tdi_avg is the current indoor average dew point temperature, ΔT_safe is the safety margin for preventing condensation, and ΔT_pipe is the temperature rise from the fresh air unit outlet to the indoor air supply outlet.

10. The method for controlling the variable air supply target of a radiant air conditioning dehumidification fresh air unit according to claim 7, characterized in that, Adjust the opening of the reheat electronic expansion valve based on the difference between To and To_target.

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