Primary return air conditioning system

Abstract

The utility model relates to indoor air conditioning technology field especially, a kind of return air conditioner system of one time, including temperature regulating component, air duct system, fresh air regulating valve, return air regulating valve, exhaust air regulating valve, air supply fan, air supply temperature sensor, first pressure sensor and second pressure sensor;Fresh air regulating valve, return air regulating valve, exhaust air regulating valve and air supply fan are respectively arranged in the fresh air pipeline, return air pipeline, exhaust air pipeline and air supply pipeline of air duct system;Air supply temperature sensor is set on air supply pipeline;First pressure sensor is set between the pipeline of fresh air regulating valve and air supply fan or between the pipeline of return air regulating valve and air supply fan;Second pressure sensor is set between the pipeline of the inlet of exhaust air pipeline and return air regulating valve or between the pipeline of the inlet of exhaust air pipeline and exhaust air regulating valve;The utility model provides a one time return air conditioner system, can maintain the whole pipe network resistance characteristic stability of air duct system, guarantee air supply fan total air supply volume stability and give consideration to air supply temperature accurate control.

Description

Technical Field

[0001] This utility model relates to the field of indoor air conditioning technology, and in particular to a single-pass return air conditioning system. Background Technology

[0002] In existing single-pass air conditioning systems, the flow regulation of fresh air, return air, and exhaust air largely relies on the direct detection and control of air volume. However, this method is easily affected by changes in the resistance of the duct network in the air duct system. For example, filter blockage, air leakage in the duct, and valve wear can all cause fluctuations in the duct network resistance, which in turn causes the actual air volume to deviate from the set value, resulting in unstable indoor environmental parameters.

[0003] Meanwhile, the adjustments between fresh air ducts, return air ducts, and exhaust air ducts are often coupled. When the valve opening of one duct is adjusted, it may cause a chain reaction of changes in pressure and flow in other ducts, resulting in a slow overall system response or oscillations, affecting the operating efficiency and stability of the primary return air conditioning system. In addition, the existing system lacks sufficient coordination between temperature and air volume regulation, making it difficult to accurately control the supply air temperature to meet indoor environmental requirements while ensuring stable supply air volume. Utility Model Content

[0004] This invention provides a primary return air conditioning system that can maintain the stability of the overall pipeline resistance characteristics of the air duct system, ensure the stability of the total air volume of the blower, and take into account the precise control of the supply air temperature.

[0005] This utility model provides a single-pass return air air conditioning system, comprising: Temperature control components; The air duct system includes a fresh air duct, a return air duct, an exhaust air duct, and a supply air duct; the outlet of the fresh air duct and the outlet of the return air duct are both connected to the inlet of the temperature control component; the outlet of the temperature control component is connected to the indoor environment through the supply air duct; the inlet of the fresh air duct and the outlet of the exhaust air duct are connected to the outdoors; the inlet of the return air duct is connected to the indoor environment through the exhaust air duct, and the inlet of the exhaust air duct is also connected to the indoor environment. The fresh air regulating valve, return air regulating valve, exhaust air regulating valve and air supply fan are respectively installed in the fresh air duct, return air duct, exhaust air duct and air supply duct; An air supply temperature sensor is installed on the air supply duct, and the opening degree of the return air regulating valve is controlled according to the air supply temperature detected by the air supply temperature sensor. A first pressure sensor is installed in the pipeline between the fresh air regulating valve and the supply fan or in the pipeline between the return air regulating valve and the supply fan. It is used to control the opening of the fresh air regulating valve according to the pressure detected at that point by the first pressure sensor in order to maintain the pressure at that point stable. The second pressure sensor is installed in the pipeline between the inlet of the exhaust duct and the return air regulating valve, or in the pipeline between the inlet of the exhaust duct and the exhaust regulating valve, and is used to control the opening of the exhaust regulating valve according to the pressure detected at that point by the second pressure sensor in order to maintain the pressure at that point stable.

[0006] In one embodiment of the present invention, an exhaust fan is further included, the exhaust fan is disposed in the exhaust duct, and the second pressure sensor is disposed in the exhaust duct between the exhaust regulating valve and the exhaust fan.

[0007] In one embodiment of the present invention, it further includes: A first controller, the input terminal of which is electrically connected to the supply air temperature sensor, and the output terminal of which is electrically connected to the actuator of the return air regulating valve; The second controller has its input terminal electrically connected to the first pressure sensor and its output terminal electrically connected to the actuator of the fresh air regulating valve. The third controller has its input terminal electrically connected to the second pressure sensor and its output terminal electrically connected to the actuator of the exhaust regulating valve.

[0008] In one embodiment of the present invention, the first controller, the second controller, and the third controller are integrated into a master controller. The master controller has signal input terminals that are electrically connected to the supply air temperature sensor, the first pressure sensor, and the second pressure sensor, respectively, and signal output terminals that are electrically connected to the actuators of the return air regulating valve, the fresh air regulating valve, and the exhaust air regulating valve, respectively.

[0009] In one embodiment of the present invention, an outdoor enthalpy sensor is also included; the outdoor enthalpy sensor is fixed at the inlet of the fresh air duct and electrically connected to the main controller; The main controller is electrically connected to the actuators of the fresh air regulating valve and the return air regulating valve. The circuit board of the main controller is provided with a hardware comparison circuit for comparing the outdoor enthalpy value with the indoor set enthalpy value. The output signal of the hardware comparison circuit controls the direction of movement of the actuators of the fresh air regulating valve and the return air regulating valve.

[0010] In one embodiment of the present invention, the air supply temperature sensor is disposed on the air supply duct between the temperature control component and the air supply fan; the first pressure sensor is disposed on a straight section of the air supply duct between the temperature control component and the air supply fan.

[0011] In one embodiment of the present invention, the temperature regulating component and the blower are fixedly connected through a common housing to form an air conditioning unit, and the outlet of the temperature regulating component and the inlet of the blower are connected through a channel inside the housing.

[0012] In one embodiment of the present invention, the air conditioning unit further includes a primary filter and a secondary filter. The primary filter, the secondary filter, the temperature control component, and the blower are connected sequentially through an internal air duct and fixed within the same unit frame. The temperature control component is a cooling coil or a heating coil.

[0013] In one embodiment of the present invention, an indoor temperature sensor is further included, which is controlled and connected to the actuator of the return air regulating valve and / or the temperature regulating component.

[0014] In one embodiment of this utility model, the fresh air regulating valve, the return air regulating valve, and the exhaust air regulating valve are all double-leaf regulating valves.

[0015] In one embodiment of this utility model, the blower is a variable frequency blower.

[0016] In one embodiment of the present invention, the air duct system further includes a mixing air box, the fresh air duct and the return air duct are both connected to the inlet of the mixing air box, the outlet of the mixing air box is connected to the inlet of the temperature control component; the first pressure sensor is disposed on the mixing air box.

[0017] The beneficial effects of this utility model are as follows: The single-pass return air conditioning system proposed in this utility model detects the pressure between the fresh air duct and the supply fan, or between the return air duct and the supply fan, and between the inlet of the exhaust duct and the return air regulating valve, or between the inlet of the exhaust duct and the exhaust air regulating valve, by setting a first pressure sensor and a second pressure sensor. Based on the detected pressure signals, the opening of the fresh air regulating valve and the exhaust air regulating valve are controlled accordingly to maintain pressure stability at the aforementioned detection points. Since stable pressure directly reflects the stability of the pipe network resistance characteristics of the corresponding section in the duct system, it ensures that the total air volume delivered by the supply fan remains stable, avoiding air volume instability caused by fluctuations in pipe network resistance. Simultaneously, by setting a supply air temperature sensor on the supply air duct and controlling the opening of the return air regulating valve based on the detected supply air temperature, precise adjustment of the supply air temperature is achieved. This allows the single-pass return air conditioning system to ensure stable air volume while also meeting the indoor temperature requirements, improving the stability and reliability of the system operation. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] In the attached diagram: Figure 1 A schematic diagram of a primary return air conditioning system provided in an embodiment of this utility model; Figure 2 This is a schematic diagram of the original single-pass return air conditioning system before the improvement of this utility model; The attached diagram is labeled as follows: 1. Air duct system; 11. Fresh air duct; 12. Return air duct; 13. Exhaust air duct; 14. Supply air duct; 15. Exhaust fan; 16. Room; 2. Fresh air regulating valve; 3. Return air regulating valve; 4. Exhaust air regulating valve; 5. Supply air temperature sensor; 6. First pressure sensor; 7. Second pressure sensor; 8. Air conditioning unit; 9. Temperature control component; 91. Cooling coil; 911. Chilled water regulating valve; 9111. Heating coil; 912. Hot water regulating valve; 9121. Pre-filter; 92. Medium-efficiency filter. Detailed Implementation

[0020] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0021] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0022] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0023] Air conditioning is closely related to our lives, especially as our living standards improve, our work, life, and production become increasingly inseparable from it. An air conditioner is a device or system that maintains indoor air parameters such as temperature, relative humidity, and airflow speed within a certain range. A primary air conditioning system typically consists of air conditioning equipment, a duct network, and control equipment. To maintain stable indoor air parameters within the required range and to save energy, automatic control of the primary air conditioning system is necessary. A schematic diagram of a primary air conditioning system is shown below. Figure 1 As shown For a single-pass return air air conditioning system that operates year-round, we can divide the automatic control into summer mode, transitional season mode, and winter mode, as detailed below: In summer mode (high temperature and high humidity), the outdoor temperature is generally above 25-28°C. To meet indoor temperature requirements, the outdoor fresh air volume is minimized to reduce energy consumption. Return air regulating valve 3 is opened to its maximum to fully utilize the relatively cool indoor air (compared to the high temperature and high humidity outdoor air). The opening of exhaust regulating valve 4 is matched with fresh air regulating valve 2 to maintain airflow balance. Indoor temperature control is achieved by controlling the opening of the water inlet valve on cooling coil 911.

[0024] In transitional season mode (mild, large temperature fluctuations), outdoor temperatures are typically between 15-25°C. At this time, it's necessary to maximize the natural cooling capacity of outdoor air, minimizing or even completely shutting down cooling coil 911 and heating coil 912 to significantly reduce energy consumption. When the outdoor air enthalpy is lower than the indoor set enthalpy (and the outdoor temperature is suitable): the system will significantly increase the opening of the fresh air regulating valve 2 and decrease the opening of the return air regulating valve 3 (even reaching 100% fresh air), using cool outdoor air to remove indoor heat. The goal is to keep the temperature / humidity of the mixed air (or direct outdoor air) close to or lower than the supply air setpoint, thereby completely or almost completely shutting down cooling coil 911. When the outdoor air enthalpy is higher than the indoor set enthalpy (or the temperature / humidity is too high), the system will decrease the opening of the fresh air regulating valve 2 (close to minimum fresh air) and increase the opening of the return air regulating valve 3, returning to a summer-like mode.

[0025] In winter mode (low temperature and dryness), the outdoor temperature is less than 15-18°C. In order to maintain indoor humidity, the fresh air volume needs to be minimized to reduce heating energy consumption. At the same time, the return air regulating valve 3 is opened to the maximum, and the opening of the exhaust air regulating valve 4 is matched with the fresh air regulating valve 2 to maintain air volume balance. Indoor temperature control is achieved by controlling the opening of the water inlet valve of the heating coil 912.

[0026] By employing refined year-round control strategies, especially by making full use of outdoor air during transitional seasons, the operating energy consumption of primary return air conditioning systems can be significantly reduced while ensuring indoor environmental comfort.

[0027] The improved transitional season control logic in this case is as follows: Figure 2 As shown, the specific solution is as follows: When the supply air temperature detected by the supply air temperature sensor 6 is less than or equal to (or greater than) the target value, the opening of the return air regulating valve 3 will be continuously increased (or decreased) until the supply air temperature reaches the target value. At this time, the opening of the fresh air regulating valve 2 and the opening of the return air regulating valve 3 are interlocked. Specifically, when the return air regulating valve 3 increases (or decreases), the return air volume increases (or decreases), and the fresh air regulating valve 2 decreases (or increases) in an interlocked manner, ensuring that the sum of the fresh air volume and the return air volume equals the total air volume of the supply fan 5. The opening of the exhaust air regulating valve 4 and the fresh air regulating valve 2 are interlocked. Specifically, when the fresh air regulating valve 2 increases (or decreases), the exhaust air volume increases (or decreases) accordingly, and the exhaust air regulating valve 4 increases (or decreases) in an interlocked manner, ensuring that the fresh air volume equals the exhaust air volume.

[0028] The above-mentioned scheme has the following drawbacks in the transitional season control logic: First, the fresh air regulating valve 2, return air regulating valve 3, and exhaust air regulating valve 4 are interlocked, and the valve openings affect each other. This makes the system regulation prone to divergence, and the valve openings are in a state of long-term oscillation, reducing valve life and resulting in poor system stability. Second, the valve opening is non-linearly related to the air volume, making it difficult for the control system to achieve interlocked logic control of air volume by controlling the valve openings. Furthermore, ensuring that the sum of the fresh air volume and return air volume equals the total air volume of the supply fan 5 is difficult to achieve through valve position control, making it difficult to guarantee the total air volume of the supply fan 5 and affecting the ventilation function of the duct system 1.

[0029] In the original design, the control logic for the fresh air and return air valves during the transition season was as follows: the valve position signal of one of the three valves (fresh air regulating valve 2, exhaust air regulating valve 4, and return air regulating valve 3) controlled the other two valves, resulting in simultaneous coupling between the control and mechanical sides. This caused the three valves to influence each other, leading to frequent valve adjustments and impacting system stability.

[0030] This solution eliminates the coupling between control valves by controlling the fresh air regulating valve 2, exhaust air regulating valve 4, and return air regulating valve 3 with their own independent signals (e.g., return air regulating valve 3 is controlled by the supply air temperature sensor 6, fresh air regulating valve 2 by the first pressure sensor 7, and exhaust air regulating valve 4 by the second pressure sensor 8). This resolves the issue of mutual interference between valves and ensures system stability. The specific solution is as follows: Please see Figure 1 , Figure 1 A primary return air air conditioning system provided in one embodiment of the present invention, such as Figure 1 As shown.

[0031] This utility model provides a single-pass air conditioning system, including a temperature control component 91, an air duct system 1, a fresh air regulating valve 2, a return air regulating valve 3, an exhaust air regulating valve 4, a blower 5, a supply air temperature sensor 6, a first pressure sensor 7, and a second pressure sensor 8. The air duct system 1 includes a fresh air duct 11, a return air duct 12, an exhaust air duct 13, and a supply air duct 14; the outlet of the fresh air duct 11 and the outlet of the return air duct 12 are both connected to the inlet of the temperature control component 91; the outlet of the temperature control component 91 is connected to the indoor environment through the supply air duct 14; the inlet of the fresh air duct 11 and the outlet of the exhaust air duct 13 are connected to the outdoor environment; the inlet of the return air duct 12 is connected to the indoor environment through the exhaust air duct 13, and the inlet of the exhaust air duct 13 is connected to the indoor environment. The fresh air regulating valve 2, return air regulating valve 3, exhaust air regulating valve 4 and air supply fan 5 are respectively installed in the fresh air duct 11, return air duct 12, exhaust air duct 13 and air supply duct 14; The air supply temperature sensor 6 is installed on the air supply duct 14, and the opening degree of the return air regulating valve 3 is controlled according to the air supply temperature detected by the air supply temperature sensor 6. The first pressure sensor 7 is installed in the pipeline between the fresh air regulating valve 2 and the air supply fan 5 or in the pipeline between the return air regulating valve 3 and the air supply fan 5, and is used to control the opening of the fresh air regulating valve 2 according to the pressure detected at that point by the first pressure sensor 7 in order to maintain the pressure at that point stable. The second pressure sensor 8 is installed in the pipeline between the inlet of the exhaust pipe 13 and the return air regulating valve 3 or between the inlet of the exhaust pipe 13 and the exhaust regulating valve 4, and is used to control the opening of the exhaust regulating valve 4 according to the pressure detected at that point by the second pressure sensor 8 in order to maintain the pressure at that point stable. By maintaining the pressure at the measuring points of the first pressure sensor 7 and the second pressure sensor 8, the overall pipeline resistance characteristics of the duct system 1 are kept stable, thereby ensuring the stability of the total air volume delivered by the blower 5.

[0032] It should be noted that in this single-pass return air conditioning system, the temperature control component 91 is the core component for air temperature regulation. The temperature control component 91 can be, for example, a heat exchange component or a device with heating wires or a cooler. The temperature control component 91 has an inlet and an outlet. The heat exchange component can specifically adopt the structural form of a cooling coil 911, a heating coil 912, or a dual-purpose heat exchange component. The cooling coil 911 is suitable for cooling conditions such as summer, while the heating coil 912 is suitable for heating conditions such as winter. The dual-purpose heat exchange component can achieve cooling and heating regulation through medium switching. The setting of this component provides a heat exchange basis for the precise control of the subsequent supply air temperature, solves the problem of insufficient coordination between temperature regulation and air volume regulation in the existing system, and ensures that the air can reach the set temperature requirement before entering the room. The air duct system 1, serving as the core channel for airflow transport, includes a fresh air duct 11, a return air duct 12, an exhaust air duct 13, and a supply air duct 14. The fresh air duct 11 introduces fresh outdoor air, the return air duct 12 recovers some treated indoor air, the exhaust air duct 13 exhausts stale indoor air, and the supply air duct 14 delivers treated air to the room. Specifically, the outlets of the fresh air duct 11 and the return air duct 12 both connect to the inlet of the temperature control component 91, allowing for pre-treatment mixing of fresh and return air before they enter the component, reducing the heat exchange load on the component. The outlet of the temperature control component 91 is directly connected to the room via the supply air duct 14, ensuring the treated air... The system efficiently delivers air into the room. The inlet of the fresh air duct 11 is connected to the outside to obtain fresh air, and the outlet of the exhaust duct 13 is connected to the outside to discharge polluted air. The inlet of the return air duct 12 is connected to the room through the exhaust duct 13, and the inlet of the exhaust duct 13 is directly connected to the room. This connection method allows for flexible adjustment of the ratio of return air to exhaust air. For example, during transitional seasons, the airflow distribution along this path can be adjusted to ensure the frequency of indoor air renewal while avoiding energy waste. The structural design of this duct system 1 clearly defines the airflow circulation path, providing a stable airflow basis for subsequent pressure control and effectively alleviating the problem of airflow deviation from the set value caused by changes in duct network resistance (such as filter blockage and duct leakage) in the existing duct system 1.

[0033] The fresh air regulating valve 2, return air regulating valve 3, and exhaust air regulating valve 4 can be either a double-leaf type regulating valve or a butterfly valve. The double-leaf type regulating valve is suitable for high-flow, high-precision flow regulation scenarios, while the butterfly valve is suitable for medium-to-small flow scenarios with limited installation space. The supply fan 5 can be either a centrifugal fan or an axial fan. The centrifugal fan is suitable for complex duct systems with high air pressure requirements, while the axial fan is suitable for scenarios with large air volume and lower air pressure requirements. The independent settings of each regulating valve provide hardware support for subsequent independent control, avoiding the problem of a single valve adjustment causing a chain reaction on the pressure and flow of other pipelines in the existing system. The supply fan 5 provides stable power for the airflow of the entire duct system 1, reducing air volume fluctuations caused by insufficient power.

[0034] The air supply temperature sensor 6 is installed on the air supply duct 14. Its specific installation location can be either on the air supply duct 14 at the outlet side of the blower 5 or on the air supply duct 14 between the outlet of the temperature control component 91 and the blower 5. When installed at the outlet side of the blower 5, it can directly detect the temperature of the air finally delivered into the room. When installed between the outlet of the temperature control component 91 and the blower 5, it can detect the temperature of the air after heat exchange in advance, facilitating earlier temperature adjustment to prevent temperature fluctuations from being transmitted to the room. This sensor detects the air supply temperature in real time and transmits the temperature signal to the control unit. The control unit adjusts the temperature based on the deviation between the detected temperature and the set temperature. Adjusting the opening of the return air regulating valve 3, for example, when the detected temperature is higher than the set temperature, increases the opening of the return air regulating valve 3 to increase the return air volume. The relatively low-temperature return air in the room mixes with the fresh air to reduce the temperature of the mixed air, thereby reducing the cooling load of the temperature control component 91. When the detected temperature is lower than the set temperature, decreases the opening of the return air regulating valve 3 to reduce the return air volume. The supply air temperature is increased by increasing the fresh air volume or adjusting the heating efficiency of the temperature control component 91. This control logic realizes the direct correlation between temperature regulation and return air flow regulation, solves the problem of insufficient coordination between temperature regulation and air volume regulation in the existing system, and ensures that the supply air temperature can accurately match the indoor demand.

[0035] The first pressure sensor 7 is used to monitor the pressure at key nodes of the duct system 1. Its installation location can be selected in the pipeline between the fresh air regulating valve 2 and the supply fan 5, or in the pipeline between the return air regulating valve 3 and the supply fan 5. When installed between the fresh air regulating valve 2 and the supply fan 5, it can monitor the pressure of the fresh air before it enters the supply fan 5 in real time, avoiding the impact of changes in the resistance of the fresh air pipeline 11 on the inlet air pressure of the supply fan 5. When installed between the return air regulating valve 3 and the supply fan 5, it can monitor the pressure of the return air before it enters the supply fan 5, ensuring that the inlet pressure of the supply fan 5 remains stable when the return air volume changes. This sensor will transmit the detected pressure information... The signal is transmitted to the control unit, which adjusts the opening of the fresh air regulating valve 2 according to the pressure deviation. When the detected pressure is higher than the set pressure, the opening of the fresh air regulating valve 2 is increased to increase the fresh air volume and reduce the pressure in the pipeline. When the detected pressure is lower than the set pressure, the opening of the fresh air regulating valve 2 is decreased to reduce the fresh air volume and increase the pressure in the pipeline. By maintaining the pressure at this point, the resistance fluctuations caused by filter blockage, pipeline leakage, etc. in the fresh air pipeline 11 or return air pipeline 12 can be indirectly offset, ensuring the stability of the ratio of fresh air volume to return air volume, and solving the problem that the air volume in the existing system is easily affected by resistance due to direct detection. The second pressure sensor 8 is used to monitor the pressure status of the exhaust duct 13. Its installation location can be either between the inlet of the exhaust duct 13 and the return air regulating valve 3, or between the inlet of the exhaust duct 13 and the exhaust air regulating valve 4. When installed between the inlet of the exhaust duct 13 and the return air regulating valve 3, it can monitor the pressure at the point where indoor air enters the exhaust duct 13 and the return air duct 12, ensuring a stable ratio of return and exhaust air flow. When installed between the inlet of the exhaust duct 13 and the exhaust air regulating valve 4, it can directly monitor the pressure of the exhaust air before it enters the exhaust air regulating valve 4, avoiding resistance in the exhaust duct 13. Changes affect the exhaust volume; the sensor transmits the pressure signal to the control unit, which adjusts the opening of the exhaust regulating valve 4 according to the pressure deviation. When the detected pressure is higher than the set pressure, the opening of the exhaust regulating valve 4 is increased to increase the exhaust volume and reduce the pressure in the pipeline. When the detected pressure is lower than the set pressure, the opening of the exhaust regulating valve 4 is decreased to reduce the exhaust volume and increase the pressure in the pipeline. This setting realizes independent control of the pressure of the exhaust pipeline 13, avoids the chain reaction of exhaust regulation on the fresh air pipeline 11 and the return air pipeline 12, and solves the problem of slow system response or oscillation caused by the coupling of regulation of each pipeline in the existing system.

[0036] This solution maintains stable pressure at two pressure sensor measurement points to offset fluctuations in duct resistance caused by filter blockage, pipe leakage, and valve wear in duct system 1. When the pressure at key nodes is stable, the airflow resistance of the entire duct system 1 can be kept within a set range. The total air volume delivered by the blower 5 is negatively correlated with the resistance of duct system 1. With the output power of the blower 5 remaining constant, stable resistance ensures stable total air volume. This control logic fundamentally solves the problems of direct air volume detection being easily affected by resistance and system oscillation caused by regulation coupling in existing systems. It decouples the regulation of each pipe and, by coordinating temperature regulation with air volume regulation, precisely adjusts the supply air temperature through the temperature response control of the return air regulating valve 3 while ensuring stable total air volume. Ultimately, it stabilizes indoor environmental parameters and improves the operating efficiency of the primary return air conditioning system.

[0037] As an optional embodiment of the present invention, it further includes an exhaust fan 15, which is disposed on the exhaust duct 13, and the second pressure sensor 8 is disposed on the exhaust duct 13 between the exhaust regulating valve 4 and the exhaust fan 15.

[0038] It should be noted that the exhaust fan 15 can be a centrifugal exhaust fan 15 or an axial flow exhaust fan 15, which solves the problem that the exhaust volume is easily affected by the fluctuation of pipeline resistance (such as pipeline leakage and filter blockage) due to insufficient exhaust power. The second pressure sensor 8 is set on the exhaust pipeline 13 between the exhaust regulating valve 4 and the exhaust fan 15. This position can directly monitor the pressure status on the inlet side of the exhaust fan 15, avoiding the interference of the resistance change of the downstream pipeline (such as the exhaust outlet section) of the exhaust fan 15 on the pressure detection accuracy, and ensuring that the pressure signal can accurately reflect the actual pressure after the exhaust regulating valve 4 is adjusted. Based on the pressure signal, the opening of the exhaust regulating valve 4 can be adjusted to achieve precise control of the exhaust volume. This case indirectly ensures the stability of the exhaust volume by stabilizing the inlet pressure of the exhaust fan 15, thereby effectively avoiding the coupling interference between exhaust regulation and fresh air and return air regulation, and improving the anti-fluctuation capability of the exhaust system.

[0039] As an optional embodiment of the present invention, it further includes a first controller, a second controller, and a third controller; The input terminal of the first controller is electrically connected to the supply air temperature sensor 6, and the output terminal is electrically connected to the actuator of the return air regulating valve 3; the input terminal of the second controller is electrically connected to the first pressure sensor 7, and the output terminal is electrically connected to the actuator of the fresh air regulating valve 2; the input terminal of the third controller is electrically connected to the second pressure sensor 8, and the output terminal is electrically connected to the actuator of the exhaust air regulating valve 4.

[0040] It should be noted that the first, second, and third controllers can be programmable logic controllers (PLCs) or single-chip microcomputers. The input of the first controller is electrically connected to the supply air temperature sensor 6 to acquire the supply air temperature signal in real time, and its output is electrically connected to the actuator of the return air regulating valve 3 (either an electric actuator or a pneumatic actuator can be used; electric actuators are suitable for conventional electrical control scenarios and have a fast response speed, while pneumatic actuators are suitable for explosion-proof or high-humidity environments and offer higher safety). By comparing the deviation between the detected temperature and the set temperature, it independently outputs control commands to drive the return air regulating valve 3 to achieve directional adjustment of the supply air temperature and return air flow. The input of the second controller... The first pressure sensor 7 receives the pressure signal, and its output is connected to the actuator of the fresh air regulating valve 2. It independently adjusts the opening of the fresh air regulating valve 2 according to the pressure deviation to ensure the pressure stability of key nodes on the fresh air side. Similarly, the third controller receives the pressure signal from the second pressure sensor 8, and its output is connected to the actuator of the exhaust air regulating valve 4. It independently controls the operation of the exhaust air regulating valve 4. The three controllers use independent signal processing and control logic and do not interfere with each other. The physical separation of the control side eliminates the regulation coupling, which solves the problem of single valve regulation causing chain changes in pressure and flow in other pipelines in the existing system. This reduces frequent valve oscillation, extends valve life, and improves the response speed and stability of the system regulation.

[0041] As an optional embodiment of this utility model, the first controller, the second controller, and the third controller are integrated into a main controller. The main controller has signal input terminals that are electrically connected to the supply air temperature sensor 6, the first pressure sensor 7, and the second pressure sensor 8, respectively, and signal output terminals that are electrically connected to the actuators of the return air regulating valve 3, the fresh air regulating valve 2, and the exhaust air regulating valve 4, respectively.

[0042] It should be noted that by integrating the first, second, and third controllers into a single controller, the integration can be achieved through either hardware or software integration. Hardware integration involves integrating the functional modules of the three controllers (such as signal acquisition, processing, and output modules) onto a single circuit board, resulting in a compact structure that reduces wiring costs and installation space. The signal input terminals of the single controller are electrically connected to the supply air temperature sensor 6, the first pressure sensor 7, and the second pressure sensor 8, respectively, ensuring that all detection signals are transmitted to the single controller in a centralized and delay-free manner. The signal output terminals correspond to the actuators of the return air regulating valve 3, the fresh air regulating valve 2, and the exhaust air regulating valve 4. The actuator is electrically connected to enable precise issuance of control commands. By preserving the independence of each control logic within a centralized control framework—that is, the main controller performs independent calculations for temperature regulation, fresh air pressure regulation, and exhaust air pressure regulation—signal interference between different control logics is avoided. This solves the problem of asynchronous regulation caused by communication delays between independent controllers. As a result, the system structure is simplified, the difficulty and cost of equipment maintenance are reduced, and the advantages of control decoupling are maintained. This ensures that the primary return air conditioning system can guarantee stable air volume and accurate air temperature while further improving the overall coordination and reliability of operation, meeting the application needs of primary return air conditioning systems of different scales.

[0043] As an optional embodiment of this utility model, it also includes an outdoor enthalpy sensor; the outdoor enthalpy sensor is fixed at the inlet of the fresh air duct 11 and electrically connected to the main controller; The main controller is electrically connected to the actuators of the fresh air regulating valve 2 and the return air regulating valve 3. The circuit board of the main controller is provided with a hardware comparison circuit for comparing the outdoor enthalpy value with the indoor set enthalpy value. The output signal of the hardware comparison circuit controls the direction of action of the actuators of the fresh air regulating valve 2 and the return air regulating valve 3.

[0044] It should be noted that the main controller is configured to perform the following controls in transitional season mode: When the outdoor air enthalpy is lower than the indoor set enthalpy, the opening of the fresh air regulating valve 2 is increased, and the opening of the return air regulating valve 3 is decreased; when the outdoor air enthalpy is higher than the indoor set enthalpy, the opening of the fresh air regulating valve 2 is decreased to the minimum fresh air opening, and the opening of the return air regulating valve 3 is increased. The transitional season control logic in this case is as follows: like Figure 2 As shown, when the supply air temperature detected by the supply air temperature sensor 6 is less than or equal to (or greater than) the target value, the opening of the return air regulating valve 3 will be continuously increased (or decreased) until the supply air temperature reaches the target value. At this time, the opening of the fresh air regulating valve 2 is interlocked with the first pressure sensor 7, and the opening of the exhaust air regulating valve 4 is interlocked with the second pressure sensor 8. The specific logic is as follows: As the opening of the return air regulating valve 3 continues to increase (or decrease), the resistance of the duct network in the air duct system 1 changes. The measurement readings of the first pressure sensor 7 (located in the pipeline between the fresh air regulating valve 2 and the supply fan 5 or between the return air regulating valve 3 and the supply fan 5) and the second pressure sensor 8 (located in the pipeline between the inlet of the exhaust duct 13 and the return air regulating valve 3 or between the inlet of the exhaust duct 13 and the exhaust air regulating valve 4) change with the change in duct network resistance. The opening of the fresh air regulating valve 2 is adjusted to keep the reading of the first pressure sensor 7 constant, and the opening of the exhaust air regulating valve 4 is adjusted to keep the reading of the second pressure sensor 8 constant.

[0045] Ultimately, the supply air temperature is maintained by adjusting the ratio of return air volume to fresh air volume, and the system pipeline resistance characteristics are kept constant by keeping the readings of the first pressure sensor 7 and the second pressure sensor 8 constant, thus ensuring the stability of the total air volume of the duct system 1.

[0046] As an optional embodiment of this utility model, the air supply temperature sensor 6 is disposed on the air supply duct 14 between the temperature control component 91 and the air supply fan 5; the first pressure sensor 7 is disposed on the straight section of the air supply duct 14 between the temperature control component 91 and the air supply fan 5.

[0047] It should be noted that the supply air temperature sensor 6 is installed on the supply air duct 14 between the temperature control component 91 and the supply air fan 5. This location allows for direct detection of the air temperature after heat exchange, before it is affected by the airflow disturbance generated by the operation of the supply air fan 5. This ensures that the temperature detection signal accurately reflects the heat exchange effect and avoids detection deviations caused by airflow disturbances from the fan. The first pressure sensor 7 is installed on a straight section of the supply air duct 14. The straight section avoids interference from airflow vortices at bends in the duct, ensuring the stability and accuracy of the pressure signal. The specific location of this straight section can be selected based on the duct layout, either near the temperature control component 91 or near the supply air fan 5, both of which can achieve stable detection. This setup solves the problem in the existing system where pressure detection is inaccurate due to flow field disturbances, thus affecting the fresh air regulation accuracy. By optimizing the sensor installation position, reliable detection signals are ensured, thereby making the opening adjustment of the fresh air regulating valve 2 more precise and further ensuring the coordinated stability of the supply air volume and supply air temperature.

[0048] As an optional embodiment of this utility model, the temperature regulating component 91 and the blower 5 are fixedly connected through a common housing to form an air conditioning unit 9, and the outlet of the temperature regulating component 91 and the inlet of the blower 5 are connected through a channel inside the housing.

[0049] It should be noted that this structure solves the problems of large footprint, complex piping connections, and easy air leakage caused by the separate installation of temperature control component 91 and air supply fan 5 in the existing system. The integrated design simplifies equipment connection, shortens airflow transmission path, thereby reducing system air leakage rate, reducing resistance loss, improving the overall operating efficiency of primary return air conditioning system, and facilitating on-site installation and subsequent maintenance.

[0050] As an optional embodiment of this utility model, the air conditioning unit 9 further includes a primary filter 92 and a secondary filter 93. The primary filter 92, the secondary filter 93, the temperature control component 91 and the blower 5 are connected in sequence through an internal air duct and fixed in the same unit frame. The temperature control component 91 is a cooling coil 911 or a heating coil 912.

[0051] It should be noted that the pre-filter 92 can be either a plate type or a bag type, and the medium-efficiency filter 93 can be either a bag type or a box type. The two types of filters are used to remove large particulate impurities and medium-sized particulate impurities from the air, respectively. The pre-filter 92, medium-efficiency filter 93, temperature control component 91 and blower 5 are connected sequentially through internal air ducts and fixed in the same unit frame. The unit frame can be a steel frame or an aluminum alloy frame to ensure that the equipment is fixed and stable. The temperature control component 91 is specified as either a cooling coil 911 or a heating coil 912, which are adapted to summer cooling and winter heating conditions, respectively. This setting solves the problems in the existing system where insufficient air cleanliness can easily cause the temperature control component 91 to become clogged and the dispersed fixed equipment can easily generate vibration and noise. By protecting the temperature control component 91 through graded filtration and integrating and fixing it to reduce vibration transmission, the service life of the temperature control component 91 is extended, the operating noise is reduced, and the cleanliness of the air supplied to the room is improved.

[0052] As an optional embodiment of this utility model, it further includes an indoor temperature sensor, which is controlled and connected to the actuator of the return air regulating valve 3 and / or the temperature regulating component 91.

[0053] It should be noted that the indoor temperature sensor can be a wall-mounted indoor temperature sensor or a duct-embedded indoor temperature sensor (the duct-embedded sensor can be installed in the return air duct 12, and indirectly reflects the indoor temperature by detecting the return air temperature). This sensor forms a control connection with the actuator of the return air regulating valve 3 and / or the temperature control component 91. The control connection can be a wired connection or a wireless communication connection, thereby solving the problem that existing systems cannot accurately match the actual indoor temperature requirements by relying solely on supply air temperature control. By combining the actual indoor temperature signal and the supply air temperature signal to form dual feedback, the opening of the return air regulating valve 3 or the heat exchange efficiency of the temperature control component 91 is adjusted, so that the indoor temperature control is more in line with the actual requirements, avoiding the situation where the supply air temperature meets the standard but the indoor temperature deviates, and improving the comfort of the indoor environment.

[0054] As an optional embodiment of this utility model, the fresh air regulating valve 2, the return air regulating valve 3, and the exhaust air regulating valve 4 are all double-leaf regulating valves.

[0055] It should be noted that this type of control valve can be either an electrically operated split-leaf control valve or a manually operated split-leaf control valve (electric is suitable for automatic control scenarios, and manual is suitable for simple control scenarios). The split-leaf control valve achieves linear flow regulation through the synchronous opening and closing of multiple sets of blades, which solves the problems of low regulation accuracy and obvious nonlinear relationship between flow and valve position when using butterfly valves and other types of control valves in existing systems. This reduces oscillations during valve regulation, improves flow control accuracy, and further ensures the stability of system regulation.

[0056] As an optional embodiment of this utility model, the blower 5 is a variable frequency blower.

[0057] It should be noted that the existing fixed-frequency blower 5 can only adjust the air volume through valve throttling, which leads to high energy consumption and slow adjustment response. By changing the fan speed to directly adjust the air volume, the energy loss caused by valve throttling is avoided, thereby significantly reducing the system's operating energy consumption. At the same time, the air volume adjustment response is faster and can quickly adapt to changes in indoor load.

[0058] As an optional embodiment of the present invention, the air duct system 1 further includes a mixing air box, the fresh air duct 11 and the return air duct 12 are both connected to the inlet of the mixing air box, and the outlet of the mixing air box is connected to the inlet of the temperature control component 91.

[0059] It should be noted that both the fresh air duct 11 and the return air duct 12 are connected to the inlet of the mixing box, so that the fresh air and return air are fully mixed in the box before entering the temperature control component 91. This avoids excessive local load on the temperature control component 91 due to uneven mixing. The outlet of the mixing box is connected to the inlet of the temperature control component 91. The airflow is evenly mixed through the mixing box, making the heat exchange of the temperature control component 91 more uniform and reducing local condensation or overheating.

[0060] This solution avoids the drawback of the control side frequently transmitting the operation signal of the main regulating valve (return air regulating valve 3) to the slave regulating valves (fresh air regulating valve 2 and exhaust air regulating valve 4) when the mechanical side has a relatively large inertia and mechanical damping suppression effect. Fresh air regulating valve 2, return air regulating valve 3 and exhaust air regulating valve 4 are regulated independently, and the valve adjustment opening does not affect each other. The system adjustment is easy to stabilize, the valve life is long, and the system stability is strong. The total air volume of the duct system 1 is easy to adjust and maintain, the system air volume can be guaranteed, and the ventilation system function can be guaranteed.

[0061] This solution achieves independent regulation of the fresh air regulating valve 2, return air regulating valve 3, and exhaust air regulating valve 4 by decoupling the control side: the return air regulating valve 3 is independently controlled by the supply air temperature sensor 6, the fresh air regulating valve 2 is independently controlled by the first pressure sensor 7, and the exhaust air regulating valve 4 is independently controlled by the second pressure sensor 8. This completely solves the drawbacks of frequent valve adjustments and system instability in the existing technology, while ensuring stable airflow in the duct system 1.

[0062] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A single-pass return air air conditioning system, characterized in that, include: Temperature control components; The air duct system includes a fresh air duct, a return air duct, an exhaust air duct, and a supply air duct; the outlet of the fresh air duct and the outlet of the return air duct are both connected to the inlet of the temperature control component; the outlet of the temperature control component is connected to the indoor environment through the supply air duct; the inlet of the fresh air duct and the outlet of the exhaust air duct are connected to the outdoors; the inlet of the return air duct is connected to the indoor environment through the exhaust air duct, and the inlet of the exhaust air duct is also connected to the indoor environment. The fresh air regulating valve, return air regulating valve, exhaust air regulating valve and air supply fan are respectively installed in the fresh air duct, return air duct, exhaust air duct and air supply duct; An air supply temperature sensor is installed on the air supply duct, and the opening degree of the return air regulating valve is controlled according to the air supply temperature detected by the air supply temperature sensor. A first pressure sensor is installed in the pipeline between the fresh air regulating valve and the supply fan or in the pipeline between the return air regulating valve and the supply fan. It is used to control the opening of the fresh air regulating valve according to the pressure detected at that point by the first pressure sensor in order to maintain the pressure at that point stable. The second pressure sensor is installed in the pipeline between the inlet of the exhaust duct and the return air regulating valve, or in the pipeline between the inlet of the exhaust duct and the exhaust regulating valve, and is used to control the opening of the exhaust regulating valve according to the pressure detected at that point by the second pressure sensor in order to maintain the pressure at that point stable.

2. The primary return air air conditioning system according to claim 1, characterized in that, It also includes an exhaust fan, which is installed in the exhaust duct, and the second pressure sensor is installed in the exhaust duct between the exhaust regulating valve and the exhaust fan.

3. The single-pass return air air conditioning system according to claim 1, characterized in that, Also includes: A first controller, the input terminal of which is electrically connected to the supply air temperature sensor, and the output terminal of which is electrically connected to the actuator of the return air regulating valve; The second controller has its input terminal electrically connected to the first pressure sensor and its output terminal electrically connected to the actuator of the fresh air regulating valve. The third controller has its input terminal electrically connected to the second pressure sensor and its output terminal electrically connected to the actuator of the exhaust regulating valve.

4. The single-pass return air air conditioning system according to claim 3, characterized in that, The first controller, the second controller, and the third controller are integrated into a master controller. The master controller has signal input terminals that are electrically connected to the supply air temperature sensor, the first pressure sensor, and the second pressure sensor, respectively, and signal output terminals that are electrically connected to the actuators of the return air regulating valve, the fresh air regulating valve, and the exhaust air regulating valve, respectively.

5. The single-pass return air air conditioning system according to claim 4, characterized in that, It also includes an outdoor enthalpy sensor; The outdoor enthalpy sensor is fixed at the inlet of the fresh air duct and electrically connected to the main controller; The main controller is electrically connected to the actuators of the fresh air regulating valve and the return air regulating valve. The circuit board of the main controller is provided with a hardware comparison circuit for comparing the outdoor enthalpy value with the indoor set enthalpy value. The output signal of the hardware comparison circuit controls the direction of movement of the actuators of the fresh air regulating valve and the return air regulating valve.

6. The single-pass return air air conditioning system according to claim 1, characterized in that, The air supply temperature sensor is installed on the air supply duct between the temperature control component and the air supply fan; the first pressure sensor is installed on a straight section of the air supply duct between the temperature control component and the air supply fan.

7. The single-pass return air air conditioning system according to claim 1, characterized in that, The temperature control component and the blower are fixedly connected through a common housing to form an air conditioning unit, and the outlet of the temperature control component and the inlet of the blower are connected through a channel inside the housing.

8. The single-pass return air air conditioning system according to claim 7, characterized in that, The air conditioning unit also includes a primary filter and a secondary filter. The primary filter, secondary filter, temperature control component, and blower are connected in sequence through internal air ducts and fixed within the same unit frame. The temperature control component is a cooling coil or a heating coil.

9. The single-pass return air air conditioning system according to claim 3, characterized in that, It also includes an indoor temperature sensor, which is controlled and connected to the actuator of the return air regulating valve and / or the temperature control assembly.

10. The single-pass return air air conditioning system according to claim 1, characterized in that, The fresh air regulating valve, return air regulating valve, and exhaust air regulating valve are all double-leaf regulating valves.

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