Fresh air system and control method thereof

Abstract

The invention discloses a fresh air system. The fresh air system comprises a plate-fin heat exchanger, a PM2.5 filtering module, a bypass control module, an air volume adjusting module and a controller. And efficient and energy-saving air filtration and heat recovery are achieved by optimizing the filter module, bypass control and air volume adjustment. The invention further provides a control method of the fresh air system, the operation state of the system is dynamically adjusted by monitoring environmental parameters in real time, and energy consumption is reduced while air quality is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of building ventilation and air treatment, and in particular relates to a fresh air system and a control method thereof. Background Art

[0002] As people's requirements for indoor air quality increase, fresh air systems are increasingly used in buildings. Traditional fresh air systems are usually equipped with simple filtering devices and fixed air volume adjustments, which are difficult to meet the needs of high efficiency, energy saving and precise control. For example, the filtration modules in the prior art mostly use a single filter, which has low filtration efficiency and high maintenance costs. In addition, traditional systems lack intelligent control and cannot dynamically adjust the air volume and heat recovery efficiency according to indoor and outdoor environmental conditions and population density. These limitations lead to high system energy consumption and difficulty in ensuring air quality. Summary of the invention

[0003] In order to solve the above problems, the present invention aims to provide an efficient and energy-saving fresh air system and a control method thereof. The system achieves efficient air purification through a three-stage filtration module (primary metal filter, electrostatic dust collection layer, HEPA filter), and is equipped with a bypass control module to reduce system resistance. The air volume adjustment module dynamically adjusts the air volume according to the personnel density and CO2 concentration, and the controller monitors the environmental parameters in real time and optimizes the system operation through a variety of sensors. The control method of the present invention realizes bypass control, air volume adjustment and heat recovery efficiency optimization through precise data acquisition and intelligent algorithms, ensuring efficient operation of the system under different working conditions.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A fresh air system, comprising a plate-fin heat exchanger, a PM2.5 filter module, a bypass control module, an air volume adjustment module, and a controller, wherein a fresh air channel and an exhaust air channel are arranged inside the plate-fin heat exchanger, wherein an inlet of the fresh air channel is connected to a fresh air inlet pipe, an inlet of the exhaust air channel is connected to an indoor exhaust air pipe, an outlet of the fresh air channel is connected to an air supply pipe, and an outlet of the exhaust air channel is connected to an exhaust air outlet pipe;

[0006] The PM2.5 filter module is connected in series to the front end of the fresh air inlet pipe. The PM2.5 filter module includes a primary metal filter, an electrostatic dust collecting layer, and a HEPA filter. The primary metal filter is a detachable and cleanable 304 stainless steel mesh. The electrode plate spacing of the electrostatic dust collecting layer is 5mm and connected to a 12kV high-voltage power supply. The HEPA filter is an H13-level folded filter element and an integrated pressure difference sensor.

[0007] The bypass control module includes a bypass air duct, an electric butterfly valve, and a stepper motor. The bypass air duct is connected in parallel to the PM2.5 filter module. The electric butterfly valve is driven by a stepper motor. The controller is connected to the stepper motor and a pressure difference sensor.

[0008] The air volume regulating module includes an EC variable frequency fan and an air volume sensor, wherein the EC variable frequency fan is installed in the air supply duct, the air volume sensor is a Hall effect flow meter, and the EC variable frequency fan is connected to a controller;

[0009] The controller includes a microcontroller, a temperature and humidity sensor, a CO2 sensor, and a PM2.5 sensor. The microcontroller has built-in program modules, including a data acquisition module, a bypass control module, an air volume adjustment module, and an efficiency optimization module.

[0010] As an improvement of the present invention, the pressure difference sensor threshold of the HEPA filter is set to 50Pa. When the pressure difference exceeds the threshold, the controller triggers the bypass air valve to open.

[0011] As an improvement of the present invention, the PID speed regulation circuit parameter of the EC variable frequency fan is K p =0.8, K i =0.2, K d =0.1, power consumption per unit air volume ≤0.45W / (m 3 / h).

[0012] As an improvement of the present invention, the efficiency optimization module of the controller calculates the heat recovery efficiency by the following formula:

[0013]

[0014] Among them, H supply is the enthalpy of the supply air, H in is the indoor air enthalpy, H out is the outdoor air enthalpy.

[0015] The present invention also provides a control method for a fresh air system, comprising the following steps:

[0016] S1. Data collection: collect indoor and outdoor temperature and humidity T through temperature and humidity sensors in , T out , H in , H out , collect PM2.5 concentration C through PM2.5 sensor PM , Collect CO2 concentration through CO2 sensor

[0017] S2. Bypass control: When any of the following conditions is met, the controller drives the electric butterfly valve to open the bypass duct:

[0018] The filter pressure difference ΔP is detected by the pressure difference sensor filter >50Pa;

[0019] Indoor and outdoor enthalpy difference |H in -Hout |<5kJ / kg;

[0020] Temperature difference |T in -T out |<2℃;

[0021] S3. Air volume adjustment: according to the number of people N and CO2 concentration The fresh air volume Q is dynamically adjusted by the EC variable frequency fan, and the calculation formula is:

[0022]

[0023] Among them, Q max is the maximum air volume of the EC variable frequency fan;

[0024] S4. Efficiency optimization: Calculate the heat recovery efficiency η in real time. If η<70%, reduce the speed of the EC variable frequency fan to 80% of the rated value and send a maintenance signal through the alarm module of the controller.

[0025] As an improvement of the present invention, the number of people N in step S1 is detected by an infrared human body sensor, and the infrared human body sensor is installed above the door frame of each room, and the detection frequency is once per minute.

[0026] As an improvement of the present invention, the CO2 concentration in step S3 The correction factor is 0.5. When the fresh air volume is forced to increase to Q max 90% of.

[0027] As an improvement of the present invention, the alarm module in step S4 pushes the maintenance signal to the user's mobile terminal through the MQTT protocol, and the user's mobile terminal displays the specific fault code and processing suggestions.

[0028] As an improvement of the present invention, the enthalpy difference calculation in step S2 adopts the following formula:

[0029] H=1.006T+(2501+1.805T)×W

[0030] Wherein, T is temperature (°C) and W is humidity ratio (kg / kg).

[0031] The beneficial effects of the present invention are:

[0032] (1) The present invention significantly improves the filtration efficiency and heat recovery efficiency of the fresh air system by optimizing the filter module and intelligent control algorithm. Compared with the prior art, this system reduces energy consumption and maintenance costs while ensuring air quality. Specifically, the HEPA filter is integrated with a differential pressure sensor, which can monitor the filter status in real time and trigger bypass to avoid excessive system resistance. The PID speed control circuit parameters of the EC variable frequency fan are optimized to ensure that the power consumption per unit air volume is as low as 0.45W / (m 3 / h), significantly lower than traditional fans.

[0033] (2) The present invention calculates the heat recovery efficiency in real time and dynamically adjusts the fan speed, so that the system can maintain efficient operation under different working conditions. The control method of the present invention realizes bypass control, air volume adjustment and heat recovery efficiency optimization through precise data collection and intelligent algorithms, ensuring that the system operates efficiently under different working conditions. The infrared human body sensor detects the number of people and dynamically adjusts the air volume, further optimizing the balance between system energy consumption and air quality.

[0034] (3) The present invention also ensures that the fresh air volume is quickly increased in a high-concentration CO22 environment to ensure indoor air quality by correcting the air volume adjustment formula of CO2 concentration. The alarm module pushes maintenance signals to the user terminal through the MQTT protocol, thereby improving the maintenance efficiency of the system. The optimization of the enthalpy difference calculation formula further improves the calculation accuracy of the heat recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a structural diagram of the fresh air system.

[0036] List of Figure Symbols:

[0037] 1. Plate-fin heat exchanger; 2. Fresh air duct; 3. Exhaust air duct; 4. Fresh air duct inlet; 5. Exhaust air duct inlet; 6. Fresh air duct outlet; 7. Exhaust air duct outlet; 8. PM2.5 filter module; 9. Bypass air duct; 10. Electric butterfly valve; 11. Stepper motor; 12. Air volume adjustment module; 13. Controller; 14. Fresh air inlet duct; 15. Indoor exhaust duct; 16. Air supply duct; 17. Exhaust outlet duct. DETAILED DESCRIPTION

[0038] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0039] The specific implementation of the present invention is described by the following examples, each of which is only a partial application of the present invention, and can be selected and adjusted according to different needs in actual applications. In the following, "Example 1" is used as the main example, and the other examples are compared by adjusting certain parameters.

[0040] Example 1

[0041] (1) Hardware connection:

[0042] A fresh air system, comprising a plate-fin heat exchanger 1, a PM2.5 filter module 8, a bypass control module, an air volume adjustment module, and a controller, wherein a fresh air channel 2 and an exhaust air channel 3 are provided inside the plate-fin heat exchanger, wherein an inlet 4 of the fresh air channel is connected to a fresh air inlet pipe 14, an inlet 5 of the exhaust air channel is connected to an indoor exhaust air pipe 15, an outlet 6 of the fresh air channel is connected to an air supply pipe 16, and an outlet 7 of the exhaust air channel is connected to an exhaust air outlet pipe 27;

[0043] The PM2.5 filter module 8 is connected in series to the front end of the fresh air inlet pipe 14. The PM2.5 filter module 8 includes a primary metal filter, an electrostatic dust collecting layer, and a HEPA filter. The primary metal filter is a detachable and cleanable 304 stainless steel mesh. The electrode plate spacing of the electrostatic dust collecting layer is 5mm and connected to a 12kV high voltage power supply. The HEPA filter is an H13 grade folded filter element and an integrated pressure difference sensor.

[0044] The bypass control module includes a bypass air duct 9, an electric butterfly valve 10, and a stepper motor 11. The bypass air duct 9 is connected in parallel to the PM2.5 filter module 8. The electric butterfly valve 10 is driven by the stepper motor 11. The controller 13 is connected to the stepper motor 11 and the pressure difference sensor.

[0045] The air volume regulating module 12 includes an EC variable frequency fan and an air volume sensor. The EC variable frequency fan is installed in the air supply pipe 16. The air volume sensor is a Hall effect flow meter. The EC variable frequency fan is connected to the controller 13.

[0046] The controller 13 includes a microcontroller, a temperature and humidity sensor, a CO2 sensor, and a PM2.5 sensor. The microcontroller has built-in program modules, including a data acquisition module, a bypass control module, an air volume adjustment module 12, and an efficiency optimization module.

[0047] The pressure difference sensor threshold of the HEPA filter is set to 50Pa. When the pressure difference exceeds the threshold, the controller triggers the bypass air valve to open.

[0048] The PID speed regulation circuit parameters of the EC variable frequency fan are K p =0.8, K i =0.2, K d =0.1, power consumption per unit air volume ≤0.45W / (m3 / h).

[0049] The efficiency optimization module of the controller 13 calculates the heat recovery efficiency by the following formula:

[0050]

[0051] Among them, H supply is the enthalpy of the supply air, H in is the indoor air enthalpy, H out is the outdoor air enthalpy.

[0052] (2) Software flow: Initialize the sensor and communication module. Collect environmental data every 5 seconds.

[0053] S1. Data collection: collect indoor and outdoor temperature and humidity T through temperature and humidity sensors in , T out , H in , H out , collect PM2.5 concentration C through PM2.5 sensor PM , Collect CO2 concentration through CO2 sensor

[0054] S2. Bypass control: When any of the following conditions is met, the controller drives the electric butterfly valve to open the bypass duct:

[0055] The filter pressure difference ΔP is detected by the pressure difference sensor filter >50Pa;

[0056] Indoor and outdoor enthalpy difference |H in -H out |<5kJ / kg;

[0057] Temperature difference |T in -T out |<2℃;

[0058] S3. Air volume adjustment: according to the number of people N and CO2 concentration The fresh air volume Q is dynamically adjusted by the EC variable frequency fan, and the calculation formula is:

[0059]

[0060] Among them, Q max is the maximum air volume of the EC variable frequency fan;

[0061] S4. Efficiency optimization: Calculate the heat recovery efficiency η in real time. If η<70%, reduce the speed of the EC variable frequency fan to 80% of the rated value and send a maintenance signal through the alarm module of the controller.

[0062] The number of people N in step S1 is detected by an infrared human body sensor, which is installed above the door frame of each room with a detection frequency of once per minute.

[0063] The CO2 concentration in step S3 The correction factor is 0.5. When the fresh air volume is forced to increase to Q max 90% of.

[0064] In step S4, the alarm module pushes the maintenance signal to the user's mobile terminal through the MQTT protocol, and the user's mobile terminal displays the specific fault code and processing suggestions.

[0065] The enthalpy difference calculation in step S2 adopts the following formula:

[0066] H=1.006T+(2501+1.805T)×W

[0067] Wherein, T is temperature (°C) and W is humidity ratio (kg / kg).

[0068] Calculate η in real time. If η<70%, reduce the speed and trigger an alarm.

[0069] Example 2

[0070] The other hardware and software settings are the same as those in Example 1, except that the pressure difference sensor threshold of the HEPA filter is adjusted to 60 Pa. By comparing Example 1 with Example 2, the influence of the pressure difference sensor threshold on the system performance is verified.

[0071] Example 3

[0072] The other hardware and software settings are the same as those in Example 1, and only the CO2 concentration correction coefficient is adjusted to 0.6. By comparing Example 1 with Example 3, the influence of the CO2 concentration correction coefficient on the air volume adjustment is verified.

[0073] Comparative Example

[0074] The existing fresh air system on the market is used, equipped with a single filter, without a bypass control module and an intelligent control algorithm. The fan uses an ordinary fixed-speed fan without a dynamic air volume adjustment function. By comparing the embodiment of the present invention with the comparative example, the performance improvement of the present invention is verified.

[0075] Comparative analysis of experimental data

[0076]

[0077] (1) Filtration efficiency: The filtration efficiencies of Examples 1, 2, and 3 are significantly higher than those of the comparative example, indicating that the three-stage filtration module (primary metal filter, electrostatic dust collection layer, and HEPA filter) of the present invention has obvious advantages in air purification. Even when the pressure difference threshold is adjusted (Example 2), the system can still maintain a high filtration efficiency.

[0078] (2) Heat recovery efficiency: The heat recovery efficiency of the present invention is higher than that of the comparative example under different working conditions, indicating that the optimization of the plate-fin heat exchanger and the intelligent control algorithm significantly improves the heat recovery performance of the system. The heat recovery efficiency of Example 1 is the highest, reaching 75.0%, while that of the comparative example is only 60.0%.

[0079] (3) Energy consumption and system resistance: The power consumption per unit air volume and system energy consumption of the present invention are significantly lower than those of the comparative example, indicating that the optimization of the EC variable frequency fan and the intelligent control algorithm effectively reduces the system energy consumption. The power consumption per unit air volume of Example 1 is only 0.45W / (m 3 / h), while the comparative example is 0.60W / (m 3 / h). The system resistance is also significantly reduced, further improving the operating efficiency of the system.

[0080] (4) Air volume regulation and CO2 concentration correction: Example 3 further optimizes the air volume regulation by adjusting the CO2 concentration correction coefficient, ensuring that the fresh air volume is quickly increased in a high-concentration CO2 environment to ensure indoor air quality.

[0081] In summary, the present invention significantly improves the filtration efficiency, heat recovery efficiency and energy consumption performance of the fresh air system by optimizing hardware configuration and intelligent control algorithm, and has significant technical advantages and application prospects.

[0082] It should be noted that the drawings only illustrate the technical ideas of the present invention, and the protection scope of the present invention cannot be limited by this shape. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. A fresh air system, comprising a plate-fin heat exchanger, a PM2.5 filter module, a bypass control module, an air volume adjustment module, and a controller, characterized in that: A fresh air channel and an exhaust air channel are provided inside the plate-fin heat exchanger, the fresh air channel inlet is connected to the fresh air inlet pipe, the exhaust air channel inlet is connected to the indoor exhaust air pipe, the fresh air channel outlet is connected to the air supply pipe, and the exhaust air channel outlet is connected to the exhaust air outlet pipe; The PM2.5 filter module is connected in series to the front end of the fresh air inlet pipe. The PM2.5 filter module includes a primary metal filter, an electrostatic dust collecting layer, and a HEPA filter. The primary metal filter is a detachable and cleanable 304 stainless steel mesh. The electrode plate spacing of the electrostatic dust collecting layer is 5mm and connected to a 12kV high-voltage power supply. The HEPA filter is an H13-level folded filter element and an integrated pressure difference sensor. The bypass control module includes a bypass air duct, an electric butterfly valve, and a stepper motor. The bypass air duct is connected in parallel to the PM2.5 filter module. The electric butterfly valve is driven by a stepper motor. The controller is connected to the stepper motor and a pressure difference sensor. The air volume regulating module includes an EC variable frequency fan and an air volume sensor, wherein the EC variable frequency fan is installed in the air supply duct, the air volume sensor is a Hall effect flow meter, and the EC variable frequency fan is connected to a controller; The controller includes a microcontroller, a temperature and humidity sensor, a CO2 sensor, and a PM2.5 sensor. The microcontroller has built-in program modules, including a data acquisition module, a bypass control module, an air volume adjustment module, and an efficiency optimization module.

2. The fresh air system according to claim 1, characterized in that: The pressure difference sensor threshold of the HEPA filter is set to 50Pa. When the pressure difference exceeds the threshold, the controller triggers the bypass air valve to open.

3. The fresh air system according to claim 1, characterized in that: The PID speed regulation circuit parameters of the EC variable frequency fan are K p =0.8, K i =0.2, K d =0.1, power consumption per unit air volume ≤0.45W / (m 3 / h).

4. The fresh air system according to claim 1, characterized in that: The efficiency optimization module of the controller calculates the heat recovery efficiency by the following formula: Among them, H supply is the enthalpy of the supply air, H in is the indoor air enthalpy, H out is the outdoor air enthalpy.

5. A control method for a fresh air system according to claim 1, characterized in that: The following steps are involved: S1. Data collection: collect indoor and outdoor temperature and humidity T through temperature and humidity sensors in , T out , H in , H out , collect PM2.5 concentration C through PM2.5 sensor PM , Collect CO2 concentration through CO2 sensor S2. Bypass control: When any of the following conditions is met, the controller drives the electric butterfly valve to open the bypass duct: The filter pressure difference ΔP is detected by the pressure difference sensor filter >50Pa; Indoor and outdoor enthalpy difference |H in -H out |<5kJ / kg; Temperature difference |T in -T out |<2℃; S3. Air volume adjustment: according to the number of people N and CO2 concentration The fresh air volume Q is dynamically adjusted by the EC variable frequency fan, and the calculation formula is: Among them, Q max is the maximum air volume of the EC variable frequency fan; S4. Efficiency optimization: Calculate the heat recovery efficiency η in real time. If η<70%, reduce the speed of the EC variable frequency fan to 80% of the rated value and send a maintenance signal through the alarm module of the controller.

6. The control method of the fresh air system according to claim 5, characterized in that: The number of people N in step S1 is detected by an infrared human body sensor, which is installed above the door frame of each room with a detection frequency of once per minute.

7. The control method of the fresh air system according to claim 5, characterized in that: The CO2 concentration C in step S3 CO2 The correction factor is 0.

5. CO2 >1000ppm, force the fresh air volume to increase to Q max 90% of.

8. The control method of the fresh air system according to claim 5, characterized in that: In step S4, the alarm module pushes the maintenance signal to the user's mobile terminal through the MQTT protocol, and the user's mobile terminal displays the specific fault code and processing suggestions.

9. The control method of the fresh air system according to claim 5, characterized in that: The enthalpy difference calculation in step S2 adopts the following formula: H=1.006T+(2501+1.805T)×W Wherein, T is temperature (°C) and W is humidity ratio (kg / kg).

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