Indoor environment quality optimization method and system based on spatial network pressure gradient

Abstract

The invention relates to the technical field of building ventilation and environment control, and provides an indoor environment quality optimization method and system based on a space network pressure gradient. The internal space of a house is divided into a clean space, a pollution source space and a transition space, a ventilation network is constructed, and a mechanical exhaust device is arranged in the pollution source space; outdoor fresh air is guided to sequentially flow through the cleaning space, the transition space and the pollution source space, and after indoor pollutants are collected, the outdoor fresh air is finally discharged out of the pollution source space; carbon dioxide concentration data are collected through a monitoring unit arranged on an airflow path key interface, the stability of the pressure gradient is judged according to the concentration gradient among the cleaning space, the transition space and the pollution source space, and the exhaust air rate is automatically adjusted to maintain directional airflow. The fluid network theory is introduced for quantitative analysis and design, so that the system performance can be predicted and optimized, and blindness and uncertainty of a traditional ventilation mode are eliminated.

Description

Technical Field

[0001] This invention relates to the field of building ventilation and environmental control technology, and more specifically, to a method and system for optimizing indoor environmental quality based on spatial network pressure gradients. Background Technology

[0002] Currently, residential buildings generally rely on air conditioning and window ventilation to regulate the indoor environment. Long-term use of air conditioning equipment can easily lead to "air conditioning sickness," while window ventilation is affected by factors such as outdoor air quality, weather, and noise, resulting in unstable and uncontrollable ventilation effects and an inability to effectively control the diffusion path of indoor pollutants.

[0003] Traditional mixed ventilation methods easily lead to cross-mixing of pollutants indoors. In particular, pollutants from concentrated pollution sources such as kitchens and bathrooms may spread to cleaner areas such as living rooms, seriously affecting the health of residents. Therefore, there is an urgent need to develop an IEQ (Integrated Energy Emission) protection technology to achieve directional and orderly ventilation that can adapt to residents' living behaviors. Summary of the Invention

[0004] In view of this, the present invention proposes an indoor environmental quality optimization method and system based on spatial network pressure gradient to solve the problems existing in the prior art.

[0005] To achieve the above objectives, this invention proposes an indoor environmental quality optimization method based on spatial network pressure gradients, comprising: The interior space of a residence is divided into clean space, pollution source space and transition space, and a ventilation network is constructed. The transition space serves as an airflow channel and distribution hub between the clean space and the pollution source space. A mechanical exhaust system is installed in the pollution source space to guide fresh outdoor air to flow sequentially through the clean space, transition space, and pollution source space. After collecting indoor pollutants, the air is finally discharged outdoors from the pollution source space. Carbon dioxide concentration data is collected by monitoring units set at key interfaces in the airflow path. The stability of the pressure gradient is determined based on the concentration gradient between the clean space, the transition space and the pollution source space, and the exhaust volume is automatically adjusted to maintain directional airflow.

[0006] Furthermore, the pressure gradient and ventilation volume satisfy the following relationship: ΔP=S×Q 2 Where Q is the air volume of the directional flow, ΔP is the pressure difference of the pressure gradient, and S is the impedance of the directional flow path.

[0007] Furthermore, the impedance of the directional flow path is synthesized by series and / or parallel flow segment impedances, wherein the synthesized impedance of n series flow segments is the sum of their individual impedances, and the synthesized impedance of m parallel flow segments satisfies the reciprocal square sum relationship.

[0008] Furthermore, the transition space is the flow and pressure balance node of the ventilation network, with the upstream being a parallel clean space flow segment and the downstream being a parallel pollution source space flow segment.

[0009] Furthermore, by adjusting the directional airflow path impedance S of the clean space... Qi The flow distribution in each cleaning space is adjusted. The flow requirement of each cleaning space is determined based on the outlet carbon dioxide concentration. When the outlet carbon dioxide concentration is not less than the sum of the carbon dioxide concentration benchmark value and the allowable fluctuation value, the directional flow path impedance S is reduced. Qi Increase the clean space flow rate; when the outlet carbon dioxide concentration is not greater than the difference between the carbon dioxide concentration benchmark value and the allowable fluctuation value, increase the directional flow airflow path impedance S. Qi Reduce the flow of air in the clean space.

[0010] Furthermore, the following constraints are established to prevent pollutants from leaking out of the port:

[0011] Among them, V Qi V represents the flow rate of the i-th cleaning space. wj This represents the flow rate of the j-th pollution source space.

[0012] On the other hand, to achieve the above objectives, this invention proposes an indoor environmental quality optimization system based on spatial network pressure gradients, comprising: Spatial ventilation network structure: Connecting clean space, transition space and pollution source space through doors and windows to form physical airflow channels; Mechanical exhaust unit: An adjustable air volume exhaust fan installed in the space of the pollution source to establish and maintain negative pressure; Monitoring unit: Distributed carbon dioxide concentration sensors are arranged in clean spaces, transition spaces, and pollution source spaces; Control unit: Connected to the mechanical ventilation unit and monitoring unit, used to receive sensor data and automatically adjust the operating status of the ventilation fan according to preset logic.

[0013] Furthermore, the control unit is configured to: Real-time comparison of carbon dioxide concentration gradients in different regions; When the carbon dioxide concentration gradient is abnormal, the total exhaust volume or the air volume of a single exhaust fan is automatically adjusted, and it also supports linkage control with the kitchen range hood.

[0014] Furthermore, the system further includes a hydraulic calculation module based on fluid network theory, used to simulate pressure distribution, air volume allocation, and fan selection optimization during the design phase.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention fundamentally avoids the disorderly diffusion and cross-mixing of pollutants indoors by establishing a stable pressure gradient and directional airflow, ensuring air quality in clean areas. Furthermore, this invention incorporates fluid network theory for quantitative analysis and design, making system performance predictable and optimizable, overcoming the blindness and uncertainty of traditional ventilation methods. This invention can automatically adjust operating parameters based on real-time monitoring data, adapting to changes in residents' window and door opening behaviors, achieving on-demand ventilation and improving user experience. The continuous negative pressure in contaminated spaces effectively prevents pollutants from the building's shared ductwork from flowing back into the room. Utilizing carbon dioxide concentration, an easily monitored parameter that effectively reflects human activity and ventilation efficiency, as a proxy indicator of system operating status makes system maintenance and fault diagnosis more intuitive and convenient. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. In the drawings: Figure 1 This is a schematic diagram of the framework of the indoor environmental quality optimization method based on spatial network pressure gradient in an embodiment of the present invention. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] Example 1 This embodiment proposes a method and system for optimizing indoor environmental quality based on spatial network pressure gradients. The core concept of this method is to treat the interior space of a residence as a controllable fluid network, achieving orderly airflow organization through active intervention. The method mainly includes the following core steps: Spatial network zoning: This involves systematically dividing the functional spaces within a residence, identifying and defining clean spaces (such as bedrooms and living rooms), pollution source spaces (such as kitchens and bathrooms), and transitional spaces that serve as airflow channels and hubs (such as corridors and foyer). This zoning constructs a clear ventilation network topology, laying the physical foundation for directional airflow organization.

[0019] Establishing and maintaining a pressure gradient to guide directional airflow: A mechanical exhaust system is installed in the pollution source space to create a negative pressure center within the residence through continuous exhaust. This aims to establish a stable pressure gradient within the dwelling, extending from the clean space through the transition space to the pollution source space. This pressure gradient, acting as a driving force, effectively guides fresh outdoor air from the clean area (e.g., through operable windows), flowing sequentially through the clean area, transition zone, and pollution source area. After collecting indoor pollutants, the air is finally exhausted outdoors from the pollution area, forming a complete directional flow path of "fresh air supply - polluted air exhaust."

[0020] Directional flow is flow along a required or predetermined path. It is not a flow with a fixed direction, nor is it a straight-line flow. Directional flow emphasizes the path, not the direction of flow. In a negative pressure directional flow ventilation network, the flow path is definite. Fluid at any point in the ventilation network, regardless of how tortuous or complex its path to the negative pressure center, always flows towards the negative pressure center. That is, in a directional flow network, there are no flow segments with uncertain directions. Therefore, a directional flow network is a branching network, not a loop network.

[0021] To achieve hydraulic adaptive control and automatic adjustment based on monitoring parameters: Carbon dioxide concentration is introduced as a key indicator parameter to verify the effectiveness of the pressure gradient and monitor system operation in real time. Monitoring points are set at key interfaces along the airflow path (such as between clean space and transition space, and between transition space and pollution source space). By monitoring and analyzing the carbon dioxide concentration gradient between clean space, transition space, and pollution source space (which should normally satisfy the relationship of "pollution source space > transition space > clean space"), the stability of the pressure gradient is indirectly reflected, thereby determining whether the directional airflow is normal.

[0022] The system automatically adjusts the total exhaust volume by monitoring the carbon dioxide concentration gradient as a proxy for the pressure gradient. When an occupant opens a window in the clean zone, the air intake increases, and the system senses the pressure change and increases the exhaust volume to maintain the gradient. When a door in the contaminated zone is opened, the room's resistance changes, and the system adjusts the exhaust fan volume accordingly. This adaptive capability ensures the stability of the ventilation path.

[0023] As a preferred embodiment, the system proposed in this embodiment is a specific implementation of the method, and its core components include: Spatial ventilation network structure: refers to the inherent or optimized physical layout of a residence, which itself constitutes an airflow channel formed by interconnecting clean zone rooms, transition zone spaces and contaminated zone rooms through door and window openings, and is the physical basis for the operation of the system.

[0024] Mechanical exhaust unit: mainly includes exhaust fans (such as axial flow fans) installed in various polluted spaces (kitchen, bathroom, etc.), which serve as the power source of the system and are responsible for generating and maintaining the required negative pressure and pressure gradient.

[0025] Monitoring unit: includes at least a distributed carbon dioxide concentration sensor deployed in clean areas, transition areas and contaminated areas, for real-time acquisition of the concentration gradient data.

[0026] Control Unit: As the "brain" of the system, it is connected to the mechanical exhaust unit and the monitoring unit. This unit is configured to receive feedback data from the monitoring unit and automatically adjust the operating status of each exhaust fan (such as start / stop and airflow adjustment) according to preset logic (such as maintaining a specific concentration gradient), thereby realizing the adaptive and intelligent operation of the system.

[0027] As a further optimization of this embodiment, a quantitative analysis and control strategy based on fluid network theory may also be included: Quantitative analysis of the hydraulic characteristics of a negative pressure directional flow ventilation network: The pressure gradient and ventilation volume follow fluid dynamics laws, specifically manifested as the pressure difference ΔP, air volume Q, and path impedance S satisfying the relationship: |ΔP| = S × Q 2 Based on this relationship, hydraulic calculations can be performed on the ventilation network to quantitatively design and optimize system performance.

[0028] Furthermore, the impedance S of the directional flow path is synthesized from the impedances of the series and / or parallel flow sections according to the following relationship: The combined impedance of n series current sections ; The combined impedance of m parallel current segments satisfies .

[0029] Regardless of the complex geometric relationship between clean spaces and pollution source spaces, the hydraulic relationships of all clean spaces are parallel to the outdoor clean air zone and the transition space; the hydraulic relationships of all pollution source spaces are parallel to the transition space and the outdoor exhaust air zone. This is illustrated in the hydraulic characteristic diagram of a negative pressure directional flow ventilation network.

[0030] The transition space G0 is the pressure and flow balance point of the ventilation network. The intrusion or infiltration of outdoor wind into the transition space G0 will cause a shift in the hydraulic conditions of the ventilation network, thereby affecting the effectiveness of the ventilation network.

[0031] Upstream of the transition space G0 is the clean space flow section. The flow rates V of each parallel clean space are... Qi Follow these rules:

[0032] By adjusting S Qi Adjust the flow distribution in each cleaning space.

[0033] The flow rate requirement of each cleanroom is determined by the carbon dioxide concentration C at the cleanroom outlet. Qi Decision, when Adjust S Qi Increase V Qi ; Increase S Qi Decrease V Qi .

[0034] in: —The baseline value for carbon dioxide concentration in clean spaces (Qi); — Permissible fluctuations in carbon dioxide concentration.

[0035] Downstream of the transition space G0 is the pollution source space flow section. The exhaust fan inlet is also the outlet of the pollution source space (the exhaust fan can indeed be installed on the outside of the pollution source space enclosure), and its carbon dioxide concentration has a similar effect to that of the clean space. However, the flow requirement of the pollution source space is determined by the purpose of preventing its internal air from flowing back out through its inlet.

[0036] The hydraulic characteristics of the inlet of the pollution source room are one of the key aspects of the hydraulic characteristics of the ventilation network. Only by constructing good hydraulic characteristics at the inlet of the pollution source space can pollutants be prevented from leaking out of the inlet under the following constraints.

[0037]

[0038] Adaptive flow distribution and control: Based on the actual air quality requirements of each space in the clean zone (such as the carbon dioxide concentration at its outlet), the impedance of the airflow channel in each clean zone can be dynamically adjusted (e.g., by adjusting the door opening), thereby achieving precise and on-demand distribution of ventilation volume in each clean zone, improving system energy efficiency and comfort.

[0039] Example 2 This embodiment details the specific installation, configuration, and operation process of the system of the present invention in an actual residential building.

[0040] 1. Reference for the construction of spatial network structure Figure 1 First, the interior space of the residence is functionally divided in order to construct the physical ventilation network structure upon which this invention relies.

[0041] Clean spaces: including living and resting spaces such as bedrooms and living rooms where high air quality needs to be maintained.

[0042] Polluted spaces: These include spaces such as kitchens and bathrooms where there are continuous or intermittent sources of pollution.

[0043] Transitional spaces: As key hubs for the organization and distribution of airflow, they are usually circulation spaces such as corridors and lobbies connecting various rooms.

[0044] To ensure smooth airflow, the doors to both the clean and contaminated areas should open towards the transition area.

[0045] 2. System Hardware Installation and Configuration Mechanical exhaust unit: Install a low-noise axial flow fan with adjustable airflow at the pre-reserved exhaust vents in the ceiling or exterior wall of the kitchen and bathroom. The rated air pressure of the fan must be sufficient to overcome the total resistance of the preset ventilation path.

[0046] Monitoring Units: Carbon dioxide concentration sensors are installed on the walls or in the center of the space in clean areas (such as living rooms), transition areas (corridors), and contaminated areas (such as bathrooms) to monitor the CO2 concentration in each area in real time. Sensors should be kept away from ventilation openings and local pollution sources to ensure data representativeness.

[0047] Control Unit: Connects all the aforementioned exhaust fans and sensors to a central controller (such as an embedded industrial computer or smart gateway) via wired or wireless means. The controller has built-in control logic algorithms and is responsible for data acquisition, processing, and command issuance.

[0048] 3. System Operation and Control Logic After the system is powered on, it enters automatic operation mode. Its core control objective is to maintain a stable pressure gradient and corresponding concentration gradient from the clean zone to the contaminated zone.

[0049] Pressure gradient establishment: The exhaust fan in the contaminated area runs continuously, creating the lowest negative pressure in the contaminated area relative to the transition area, and a lower negative pressure in the transition area relative to the clean area. This establishes a stable pressure gradient.

[0050] Directional flow formation: Driven by the pressure gradient, fresh outdoor air enters from the slightly open windows or dedicated fresh air inlets of the clean area, flows through each room of the clean area, carries pollutants such as CO2 produced by the human body, merges into the transition zone, is then drawn into the polluted area, and is finally discharged outdoors by the exhaust fan.

[0051] Status monitoring and adaptive control: The control unit compares the CO2 concentrations in the clean zone, transition zone, and contaminated zone in real time. When the monitored concentration gradient meets the predetermined relationship of "contaminated source space > transition space > clean space", the system is considered to be operating normally.

[0052] If the gradient is abnormal, the controller will automatically increase the total exhaust volume or adjust the speed of a specific fan according to a preset algorithm until the normal gradient is restored. This closed-loop control process ensures the system's adaptive capability.

[0053] Furthermore, this embodiment details how to utilize the fluid network theory described in this invention to perform quantitative analysis during the system design and optimization phase, in order to ensure that its performance reaches its optimal level.

[0054] 1. Spatial ventilation network abstraction The actual physical space of the residence (such as Figure 1 The model is abstracted as a fluid network model consisting of nodes (representing each room space) and branches (representing airflow channels such as doors, windows, and ventilation ducts).

[0055] 2. Resistance characteristic modeling Based on fluid mechanics theory, the local resistance and friction resistance of each branch (such as a door at different opening degrees) are quantitatively calculated to determine its resistance characteristic coefficient S, and a pressure difference-airflow relationship model for that branch is established: ΔP=S×Q 2 This is the basis for quantitative calculations.

[0056] 3. Establishment and Solution of Space Ventilation Network Equations Based on the network topology, apply Kirchhoff's laws: Law of Conservation of Mass (Nodal Airflow Balance): The sum of the airflow flowing into any node is equal to the sum of the airflow flowing out of that node.

[0057] Law of conservation of energy (pressure balance in a closed loop): In any closed loop, the algebraic sum of the pressure drops in each branch is zero.

[0058] The equations of all nodes and loops are combined to form a nonlinear system of equations. Then, an iterative method (such as the Newton-Raphson method) is used to solve the system using a computer to obtain the pressure values ​​of all nodes and the actual ventilation volume of all branches in the network under given boundary conditions (such as the performance curve of the exhaust fan and the opening of the window).

[0059] 4. Design optimization and operating condition simulation Based on the above hydraulic calculations, the following key design optimizations can be completed before construction: Fan selection: Based on the total system resistance and required total air volume calculated by simulation, scientifically select the air pressure and air volume parameters of the exhaust fan to avoid "oversized engine for undersized vehicle" or insufficient air pressure.

[0060] Performance prediction: Simulate the whole-house pressure distribution and airflow allocation under different operating conditions to verify the stability of the pressure gradient and the effectiveness of the airflow path in advance.

[0061] Sensitivity analysis: assesses the impact of changes in key parameters on system performance, thereby guiding accuracy requirements during construction.

[0062] Key points for operation and maintenance: Keep the room containing the pollution source sealed and continuously ventilated; windows and doors outside the rooms can be opened and closed by the residents as needed, and the system will automatically adapt; kitchen exhaust fans should be used as needed.

[0063] In daily use, users can open and close the exterior windows and doors of the cleaned space as needed; the system has adaptive adjustment capabilities. It is essential to ensure the airtightness of the pollution source space, and its exhaust fan is recommended to operate continuously for 24 hours to effectively prevent backflow of pollutants from building drainage drains and shared air ducts. As the kitchen exhaust fan is a device with a high instantaneous airflow, this system can be synchronized with it during operation or temporarily avoid its peak airflow, resuming normal operation after it stops.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing indoor environmental quality based on spatial network pressure gradient, characterized in that, include: The interior space of a residence is divided into clean space, pollution source space and transition space, and a ventilation network is constructed. The transition space serves as an airflow channel and distribution hub between the clean space and the pollution source space. A mechanical exhaust system is installed in the pollution source space to guide fresh outdoor air to flow sequentially through the clean space, transition space, and pollution source space. After collecting indoor pollutants, the air is finally discharged outdoors from the pollution source space. Carbon dioxide concentration data is collected by monitoring units set at key interfaces in the airflow path. The stability of the pressure gradient is determined based on the concentration gradient between the clean space, the transition space and the pollution source space, and the exhaust volume is automatically adjusted to maintain directional airflow.

2. The method according to claim 1, characterized in that, The pressure gradient and ventilation volume satisfy the following relationship: ΔP=S×Q 2 Where Q is the air volume of the directional flow, ΔP is the pressure difference of the pressure gradient, and S is the impedance of the directional flow path.

3. The method according to claim 2, characterized in that, The impedance of the directional flow path is synthesized by series and / or parallel flow segments, wherein the synthesized impedance of n series flow segments is the sum of the individual impedances, and the synthesized impedance of m parallel flow segments satisfies the reciprocal square sum relationship.

4. The method according to claim 1, characterized in that, The transition space is the flow and pressure balance node of the ventilation network, with the upstream being a parallel clean space flow segment and the downstream being a parallel pollution source space flow segment.

5. The method according to claim 1, characterized in that, By adjusting the directional airflow path impedance S in the clean space Qi The flow distribution in each cleaning space is adjusted. The flow requirement of each cleaning space is determined based on the outlet carbon dioxide concentration. When the outlet carbon dioxide concentration is not less than the sum of the carbon dioxide concentration benchmark value and the allowable fluctuation value, the directional flow path impedance S is reduced. Qi Increase the clean space flow rate; when the outlet carbon dioxide concentration is not greater than the difference between the carbon dioxide concentration benchmark value and the allowable fluctuation value, increase the directional flow airflow path impedance S. Qi Reduce the flow of air in the clean space.

6. The method according to claim 1, characterized in that, By constructing the following constraints, pollutants can be prevented from leaking out of the inlet: ， Among them, V Qi V represents the flow rate of the i-th cleaning space. wj This represents the flow rate of the j-th pollution source space.

7. An indoor environmental quality optimization system based on spatial network pressure gradient, characterized in that, include: Spatial ventilation network structure: Connecting clean space, transition space and pollution source space through doors and windows to form physical airflow channels; Mechanical exhaust unit: An adjustable air volume exhaust fan installed in the space of the pollution source to establish and maintain negative pressure; Monitoring unit: Distributed carbon dioxide concentration sensors are arranged in clean spaces, transition spaces, and pollution source spaces; Control unit: Connected to the mechanical ventilation unit and monitoring unit, used to receive sensor data and automatically adjust the operating status of the ventilation fan according to preset logic.

8. The system according to claim 6, characterized in that, The control unit is configured to: Real-time comparison of carbon dioxide concentration gradients in different regions; When the carbon dioxide concentration gradient is abnormal, the total exhaust volume or the air volume of a single exhaust fan is automatically adjusted, and it also supports linkage control with the kitchen range hood.

9. The system according to claim 6, characterized in that, The system further includes a hydraulic calculation module based on fluid network theory, used to simulate pressure distribution, air volume allocation, and fan selection optimization during the design phase.

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