CN116026404A - A real-time monitoring system for heat and mass flow at the boundary of naturally ventilated buildings - Google Patents

Abstract

The invention discloses a real-time monitoring system for thermal mass flow at the boundary of a naturally ventilated building, which includes a coupled pendulum sensor, a real-time test module, a data transmission module, and a cloud control module, and each coupled pendulum sensor is composed of Composed of cycloids, throttle plates, temperature sensors and electronic gyroscopes; the real-time test module is composed of coupled pendulum sensors arrayed at the boundary openings of naturally ventilated buildings: the coupled pendulum sensors are numbered according to test requirements to realize natural ventilation buildings Boundary information measurement at different positions of the boundary opening; the data transmission module is used to receive the data signal of the coupled pendulum sensor, and connect with the communication serial port of the PC through the built-in communication interface of the temperature sensor and electronic gyroscope to realize the transmission of real-time monitoring data; The cloud control module is used to determine the optimal sampling frequency; display data signals and spectrum analysis results to achieve coordinated control of the building as a whole.

Description

A real-time monitoring system for heat and mass flow at the boundary of naturally ventilated buildings

technical field

The invention relates to the technical field of ventilation measurement, in particular to a real-time monitoring system for thermal mass flow (temperature, ventilation rate) at the boundary of a naturally ventilated building.

Background technique

Natural ventilation technology has great energy-saving potential, but it is strongly affected by the outdoor microclimate, factors such as the randomness and fluctuation of outdoor wind, which make it a huge challenge to quantify the airflow boundary of natural ventilation large industrial buildings, especially the wind speed of natural ventilation building vents The field of online real-time high-precision testing methods for characteristics. Although the traditional ultrasonic anemometer method can obtain more accurate real-time measurement results, it cannot be widely used due to its expensive probe and data processing equipment. In order to obtain and quantify the complex characteristics of the airflow boundary of multiple natural ventilation openings in large buildings, it is necessary to collect high-frequency test data, and it is necessary to ensure that the measuring instruments can complete real-time online testing.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, optimize and innovate the online high-precision measurement method of naturally ventilated industrial buildings in the field of ventilation technology, and develop a coupled pendulum sensor device coupled with a temperature sensor and an electronic gyroscope. On the basis of obtaining real-time monitoring data, upload the data to the cloud, select and control the data collection, display the most reasonable signal sampling frequency, and provide a natural ventilation building boundary heat based on sensor device development, real-time testing, data transmission, and cloud control. Mass flow (temperature, ventilation) real-time monitoring system.

The purpose of the present invention is achieved by the following technical solutions:

A real-time monitoring system for heat and mass flow at the boundary of a naturally ventilated building, including a coupled single pendulum sensor, a real-time test module, a data transmission module, and a cloud control module. Each of the coupled single pendulum sensors consists of two identical cycloids, a It consists of a throttle plate, a temperature sensor and an electronic gyroscope. The temperature sensor and the electronic gyroscope are respectively set at the center of the front and back sides of the throttle plate. One end of the cycloid is connected to the throttle plate, and the other end is used to fix the Tested natural ventilation building boundaries: temperature sensors and electronic gyroscopes are equipped with built-in communication interfaces for real-time and continuous monitoring of temperature changes and ventilation volume changes at building boundary openings to reflect the temperature and ventilation volume at each opening Changes, as well as heat transfer and mass transfer conditions; the real-time test module is composed of coupled pendulum sensors arranged in an array at the boundary opening of a naturally ventilated building: number the coupled pendulum sensors according to the test requirements to realize the boundary opening of a naturally ventilated building Boundary information measurement at different locations, the boundary information includes temperature changes, ventilation changes;

The data transmission module is used to receive the data signal of the coupled pendulum sensor, and is connected with the communication serial port of the PC through the built-in communication interface of the temperature sensor and the electronic gyroscope, so as to realize the transmission of real-time monitoring data;

The cloud control module receives all the data signals from the data transmission module, realizes the frequency spectrum analysis of the natural ventilation building boundary temperature and the ventilation volume signal through the C++ programming language on the Matlab platform, and obtains the specific air flow changes at different positions of the natural ventilation building boundary openings characteristics, determine the optimal sampling frequency actually required for specific engineering problems; and selectively display data signals and spectrum analysis results as required through the online control panel to achieve coordinated control of the building as a whole.

Furthermore, the boundary of a naturally ventilated building is affected by the outdoor wind speed and wind direction, and there are two swing states of airflow outflow and inflow. The swing states of the coupled pendulum sensors at different positions of the boundary opening are different; the electronic gyroscope components are based on the theory of conservation of angular momentum and The acceleration law can convert the recorded angle-related signal into a wind speed signal, and then calculate the actual ventilation volume signal according to the wind speed result.

Furthermore, when arranging the coupled pendulum sensor, ensure that the lengths of the two cycloids are consistent, and the heights of the temperature sensor and the electronic gyroscope are consistent, so as to realize the correct measurement of the airflow temperature and ventilation volume at the boundary of the naturally ventilated building.

Further, the built-in communication interface of the temperature sensor and the electronic gyroscope is connected with the communication serial port of the PC based on Bluetooth transmission, which can realize fast real-time wireless connection between several coupled single pendulum sensor arrays and the PC at the same time, and then transfer the real-time measurement data Upload to the cloud.

Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

1. The present invention couples a temperature sensor with an electronic gyroscope for monitoring temperature changes and ventilation volume changes at the boundaries of naturally ventilated buildings, and optimizes and innovates the online high-precision measurement method for opening boundaries of naturally ventilated buildings in the field of ventilation technology. Connect the built-in communication interface of the coupled pendulum sensor with the communication serial port of the PC to realize the real-time monitoring requirement and upload the real-time test data set to the cloud, which is beneficial to the subsequent spectrum analysis of the signal. The invention also proposes to use the Matlab platform to calculate and analyze suitable sampling frequency as a supplement. This real-time monitoring system for heat and mass flow (temperature, ventilation) at the boundaries of naturally ventilated buildings can realize online real-time and accurate monitoring of coupled pendulum sensor arrays at different positions of the boundary openings, and provide reasonable sampling frequencies according to different needs, with low cost and It has good economic benefits and can meet the requirements of multi-boundary measuring point test for natural ventilation of large industrial buildings.

2. The monitoring system of the present invention acquires and processes high-frequency data, cooperates with the spectrum analysis algorithm, can accurately obtain the airflow characteristics at different positions of the boundary openings of naturally ventilated buildings in real time, and can be used for instant research on large-scale naturally ventilated buildings.

3. The system of the present invention deduces the wind speed conversion formula according to the theory of conservation of angular momentum and the law of acceleration, realizes the conversion of the angle signal into the wind speed signal, and then calculates the ventilation volume signal, compared with the method of directly measuring the wind speed with an ultrasonic anemometer and then calculating the ventilation volume method, the sensor is more economical and reduces the cost of multi-measuring point experiments in large spaces.

Description of drawings

Fig. 1 is a schematic diagram of the composition and structure of the real-time monitoring system for heat and mass flow at the boundary of a naturally ventilated building according to the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

A real-time monitoring system for heat and mass flow at the boundary of a naturally ventilated building, as shown in Figure 1, includes coupled pendulum sensors connected in sequence, a real-time test module, a data transmission module, and a cloud control module.

Each coupled pendulum sensor consists of 2 identical cycloids, a throttle plate, a temperature sensor and an electronic gyroscope, the temperature sensor and electronic gyroscope are located in the center of the front and back sides of the throttle plate When arranging a coupled pendulum sensor, it should be ensured that the two cycloids have the same length, and the temperature sensor and the electronic gyroscope have the same height, so as to realize the correct measurement of the airflow temperature and ventilation volume at the boundary of the naturally ventilated building. Based on the theory of conservation of angular momentum and the law of acceleration, the electronic gyroscope component can convert the recorded angle-related signal into a wind speed signal, and then calculate the actual ventilation volume signal according to the wind speed result. The cycloid length is 40mm; the size of the throttle plate is 150×150mm, and there are evenly distributed orifices on it, the diameter of the orifice is 2mm, allowing airflow to pass through; the model of the temperature sensor is DS18B20, and the temperature range is -55°C to +125°C , to meet the actual measurement requirements of naturally ventilated buildings; the model of the electronic gyroscope is MPU6050, and the variables that can be recorded include angles (A ₁ , A ₂ , A ₃ ) and accelerations (a ₁ , a ₂ , a ₃ ) and angular velocity (W ₁ , W ₂ , W ₃ ). The electronic gyroscope records the wind angle, angular velocity, and angular acceleration signals at the airflow boundary of the window. Based on the theory of conservation of angular momentum and the law of acceleration, the angle-related signals are converted into wind speed signals, so the calculation of ventilation can be obtained. Both the temperature sensor and the electronic gyroscope have built-in communication interfaces, which are used to realize real-time continuous monitoring of temperature changes and ventilation volume changes at building boundary openings, so as to reflect the temperature and ventilation volume variation characteristics of each opening, as well as heat transfer, Mass transfer: by determining the purpose of the test and the location to be tested, the coupled pendulum sensor is arranged at the target position on the boundary of the naturally ventilated building to form an array and start the test. This process is called entering the real-time test module;

The real-time test module is composed of coupled pendulum sensors arranged in an array at the boundary opening of the naturally ventilated building: affected by the outdoor wind speed and wind direction at the boundary of the naturally ventilated building, there are two swing states of airflow outflow and inflow, and the coupling at different positions of the boundary opening The pendulum sensors have different swing states; naturally ventilated buildings may have multiple boundary vents, and the specific number and form of sensor arrangement are determined according to the details of the tested naturally ventilated buildings, and a reasonable coupled pendulum sensor array is arranged according to the details. When carrying out the measurement, the coupled pendulum sensor array can be arranged and numbered according to the number of openings in the naturally ventilated building, and the temperature change at the opening of the building boundary and the change of ventilation flow can be monitored continuously in real time to reflect the temperature and speed changes at each opening. characteristics, as well as heat transfer and mass transfer,

The data transmission module connects the built-in communication interface of multiple coupled single pendulum sensors with the communication serial port of the PC, and determines the available data set according to the data obtained by the real-time measurement of the coupled single pendulum sensors, which can realize the connection between multiple movable coupled single pendulum sensors and the PC. Simultaneous fast wireless connection between devices, and then upload real-time measurement data to the cloud. The data transmission module is the transfer transmission link before cloud control, which can transmit and obtain thermal and quality monitoring signals such as temperature and ventilation volume at different locations on the boundary of naturally ventilated buildings according to the actual needs of studying different problems.

The cloud control module is based on the C++ programming language, Matlab platform, and online control panel to realize online display and control research on data signals; the cloud control module receives all data signals from the data transmission module, and the natural ventilation can be realized through the C++ programming language on the Matlab platform Spectrum analysis of building boundary temperature and ventilation volume signals helps to obtain specific airflow variation characteristics at different positions of natural ventilation building boundary openings, and determine the best sampling frequency actually required for specific engineering problems; supplemented by related online control panels, Data signals and spectrum analysis results can be selectively displayed as needed, which is helpful for coordinated control of the building as a whole during the research process;

Specifically, according to the actual needs of different problems, the data is uploaded to the cloud for analysis and processing, and the cloud data is summarized to display the thermal mass transmission signals such as temperature, velocity, and ventilation volume at different locations on the boundary of the actual naturally ventilated building. Based on the C++ programming language, use the Matlab platform to realize the spectrum analysis of the airflow measurement signal, and finally determine the optimal sampling frequency required for specific engineering problems; through the online control panel, the display of the results of the data transmission module can be selected and controlled.

Specifically, the system of the present invention derives the wind speed conversion formula according to the theory of conservation of angular momentum and the law of acceleration, realizes the conversion of the angle signal into a wind speed signal, and then calculates the ventilation volume signal, compared with the direct measurement of the wind speed by the ultrasonic anemometer and then the calculation of the ventilation volume In this way, the sensor is more economical and reduces the cost of multi-measuring point experiments in a large space. The specific derivation process is as follows:

The alternating signals recorded by the coupled pendulum sensor include temperature (t), three-axis angle (A ₁ , A ₂ , A ₃ ), acceleration (a ₁ , a ₂ , a ₃ ), angular velocity (W ₁ , W ₂ , W ₃ ) Among the ten parameters, 1, 2, and 3 represent the three-axis directions of x _SVA , y _SVA , and z _SVA respectively. Because the real-time monitoring process is in a swing state, the first ten parameters are all recorded in the three-axis directions x _SVA , y _SVA , and z _SVA of the coordinate system during swing. The force analysis of the coupled pendulum sensor is carried out in the three-axis direction (x, y, z direction) of the coordinate system at rest. The mass M of the entire coupled pendulum sensor has gravity Mg (gravitational acceleration g), traction force T and The force F of the wind in the tangential direction (under the action of the wind with a wind speed of U), these three forces, the resultant force along the tangential direction of the swing (in the x direction) and perpendicular to the tangent direction (in the z direction) satisfies Newton’s first The second law, in the form:

FcosA ₃ -TsinA ₃ = _Max

FsinA ₃ +TcosA ₃ -Mg=Ma _z

Wherein, a _x , a _z correspond to two directions of the coordinate system x and z at rest. When the swing occurs, there is a rotation deflection angle between the three-axis direction (x _SVA , y _SVA , z _SVA direction) of the coordinate system of the coupled pendulum sensor and the three-axis direction (x, y, z direction) of the coordinate system when it is actually stationary. The relationship between them is as follows:

x＝x _SVA cosA ₃ -z _SVA sinA ₃

y=y _SVA

z=x _SVA sinA ₃ +z _SVA cosA ₃

Therefore, a _x and a _z can be calculated from a ₁ , a ₃ and A ₃ , and the specific relationship is as follows:

a _x ＝a ₁ cosA ₃ -a ₃ sinA ₃

a _z =a ₁ sinA ₃ +a ₃ cosA ₃

The component of the wind force F generated by the wind speed U along the windward direction can be obtained according to the air resistance formula of the low-speed moving object:

FcosA ₃ ＝C _D ρU ² S

Where _CD is the air resistance coefficient during motion, ρ is the air density, and S is the effective area of the throttle plate forming the coupled pendulum sensor.

The drag coefficient C _D can be determined by its functional relationship with the Reynolds number Re,

Among them, a, b, and c are three coefficient variables that need to be determined according to different test situations.

The relationship between the Reynolds number Re and the wind speed U is as follows:

Among them, L represents the characteristic length of the throttle plate constituting the coupled pendulum sensor, and μ is the viscosity coefficient of air.

From this, the wind speed signal obtained from the angle signal can be obtained:

The ventilation rate can be obtained by multiplying the wind speed by the area of the boundary opening, and the area of the boundary opening depends on different test situations.

The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention, and the above specific embodiments are only illustrative and not restrictive. Without departing from the gist of the present invention and the scope of protection of the claims, those skilled in the art can also make many specific changes under the inspiration of the present invention, and these all belong to the protection scope of the present invention.

Claims (4)

1. A real-time monitoring system for heat and mass flow at the boundary of a naturally ventilated building is characterized in that it includes a coupled single pendulum sensor, a real-time test module, a data transmission module, and a cloud control module, and each of the coupled single pendulum sensors is composed of two complete Composed of the same cycloid, a throttle plate, a temperature sensor and an electronic gyroscope, the temperature sensor and electronic gyroscope are respectively set at the center of the front and back sides of the throttle plate, one end of the cycloid is connected to the throttle plate, and the other One end is used to fix the boundary of the naturally ventilated building to be tested: the temperature sensor and the electronic gyroscope are equipped with built-in communication interfaces, which are used to realize real-time and continuous monitoring of the temperature changes and ventilation volume changes at the openings of the building boundary to reflect the changes of each opening. Changes in temperature and ventilation, as well as heat transfer and mass transfer; The real-time test module is composed of coupled pendulum sensors arranged in an array at the boundary opening of the naturally ventilated building: the coupled pendulum sensors are numbered according to the test requirements to realize boundary information measurement at different positions of the boundary opening of the naturally ventilated building. Information includes temperature changes, ventilation volume changes; The data transmission module is used to receive the data signal of the coupled pendulum sensor, and is connected with the communication serial port of the PC through the built-in communication interface of the temperature sensor and the electronic gyroscope, so as to realize the transmission of real-time monitoring data; The cloud control module receives all the data signals from the data transmission module, realizes the frequency spectrum analysis of the natural ventilation building boundary temperature and the ventilation volume signal through the C++ programming language on the Matlab platform, and obtains the specific air flow changes at different positions of the natural ventilation building boundary openings characteristics, determine the optimal sampling frequency actually required for specific engineering problems; and selectively display data signals and spectrum analysis results as required through the online control panel to achieve coordinated control of the building as a whole. 2. According to claim 1, a real-time monitoring system for heat and mass flow at the boundary of a naturally ventilated building is characterized in that the boundary of a naturally ventilated building is affected by the outdoor wind speed and wind direction, and there are two swing states of airflow outflow and inflow, and the boundary openings are different. The swing state of the coupled pendulum sensor at the position is different; the electronic gyro element can convert the angle-related signal it records into a wind speed signal based on the theory of conservation of angular momentum and the law of acceleration, and then calculate the actual ventilation volume signal based on the wind speed result. 3. according to claim 1, a kind of natural ventilation building boundary heat and mass flow real-time monitoring system is characterized in that, when arranging the coupled pendulum sensor, it is ensured that the lengths of the two cycloids are consistent, the height of the temperature sensor and the electronic gyroscope are consistent, In order to realize the correct measurement of airflow temperature and ventilation volume at the boundary of naturally ventilated buildings. 4. According to claim 1, a real-time monitoring system for heat and mass flow at the boundary of a naturally ventilated building is characterized in that the built-in communication interface of the temperature sensor and the electronic gyroscope is connected with the communication serial port of the PC based on bluetooth transmission, and several units can be realized. Simultaneous fast real-time wireless connection between the coupled pendulum sensor array and the PC, and then upload real-time measurement data to the cloud.

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