Đồ án tốt nghiệp: Design system for controlling and monitoring CO2 concentration in the building

It utilizes BMS and devices such as the central control unit BCU, digital control DDC – C46, inverter, and focuses on controlling the ventilation fan based on CO2 sensors.. Additionally,

OVERVIEW

Overview of the Building Management System (BMS)

In the field of automation, there have been numerous studies on areas such as Process Control Technology and Distributed Control Systems However, one area that has garnered a lot of attention is the Building Management System (BMS) For a high-rise building with many devices, the requirement to manage these devices to control energy consumption, facilitate maintenance, and simplify repairs is extremely essential The Building Automation System was developed and evolved to meet this need Arising from these practical demands, many automation companies worldwide, such as Siemens, Honeywell, ABB, and Echelon, have researched and introduced standards and equipment to meet these increasing needs

The inability to ensure air quality in the room has caused several issues regarding both health and mental well-being By using CO2 sensors to measure the CO2 concentration in the air, combined with inverters and BMS technology, the ventilation fan system can be operated efficiently and effectively

Our research project focuses on the Delixi EM60 and IG5A inverters for controlling ventilation fans, constructing a model to meet the objectives and research content.

Reason for choosing the topic

The ventilation system, also known as the air conditioning system, plays a significant role in the construction of buildings and production systems in factories The challenge is to monitor and operate the equipment via inverters quickly and easily to achieve high efficiency Therefore, our group decided to research the topic

"Application of BMS in Monitoring and Controlling CO2 Levels."

The objective of the research topic

- Presenting standards for ventilation systems

- Designing and implementing a BMS model to operate the ventilation system in a laboratory room

- Designing a web-based interface for monitoring and controlling the system

- Assessing the results achieved after the research and implementation of the model

Research methodology

- Studying the theory and standards regarding ventilation systems in buildings, researching previous projects, and understanding their applications

- Building a practical model: establishing connections between devices, testing compatibility between devices and control software, comparing collected data.

Research subjects

- Supply Fan and Exhaust Fan

Project content

- Introduction of the research project, summary of reasons for choosing the topic, objectives, research subjects, and expected outcomes after completing the project

Chapter 2: DESIGN AND MODEL CALCULATIONS

- Calculating fan power and ventilation positions

Chapter 3: MODEL IMPLEMENTATION AND MONITORING, CONTROL INTERFACE DESIGN

- Designing and implementing the BMS model

- Designing the monitoring interface, control interface, operating the Delixi EM60 inverter and IG5A inverter to control the ventilation fan on the BMS Control Software

Chapter 4: MODEL OPERATION AND RESULTS EVALUATION

- Using the BMS Control Software

- Manual operation of the model

Project Implementation Process

There are 3 main blocks: Design, Construction, and Operation

Within the design block, there will be 3 subparts:

- Calculate the model's usage volume

- Calculate the airflow rate and fan power

- Calculate the wind speed through the air inlet

- Celect the air inlet location

- Determine the maximum CO2 concentration in the room

- Control and monitoring interface on a website

- Device arrangement in the electrical panel

- Install air vent on ceiling panel

- Reinforce floor panel to withstand fan suction force

- Switching the switch to Auto mode

- Observing the CO2 sensor signal

- Switching the switch to Manual mode

- Press the ON/OFF button

- Proceed to monitor software interface parameters

MODEL DESIGN

Design process

The aim of the project is to establish a model that demonstrates forced air exchange using a ventilation fan system to control CO2 concentration in a laboratory room A clear flowchart outlining the necessary tasks is essential

8 The project began with the most basic theories of a ventilation system, based on standards from Vietnam and the United States, combined with design guidebooks From there, the team outlined the necessary tasks, starting with building the model The model created must realistically simulate the referenced object (GE room) Next is developing the control requirements The model needs to ensure that the CO2 concentration in the room does not exceed the maximum allowable limit while also ensuring that the speed of the exhaust and supply fans responds promptly to changes in CO2 concentration Once the necessary airflow is determined, the next step is calculating the optimal air vent positions for the model Economic efficiency calculations are also essential due to limited finances and restricted availability of borrowed equipment Only by overcoming these challenges can the project proceed to the construction phase The construction phase includes assembling the electrical cabinet, ceiling panel, and floor panel, reinforcing the model, and installing air ducts and sensors The operation phase will commence once the model is complete, followed by evaluating the achieved results Continuous testing and evaluation will be carried out until the requirements are met, and the manual monitoring and control interface must also be completed Finally, the results will be reported, and the graduation project will be concluded

Through the model shown in Figure 2.1, the approach to solving the problem as well as the workload has been identified.

Building model parameters

❖ Reference object: GE laboratory room

Area of the GE room:

Volume of the GE room:

Area of the GE room:

Volume of the GE room:

With the goal of constructing a model that accurately represents reality, the model will have an approximate volume ratio of 1:5000

Establishing control requirements

According to ASHRAE 62.1 - 2016 standard [3], the CO2 concentration measured in outdoor air typically falls between 300 to 500 ppm The higher the amount of fresh air supplied into the room, the lower the difference in CO2 concentration between indoor and outdoor environments or the more diluted the CO2 concentration in the room becomes If the CO2 amount is taken at a horizontal axis from a group of people engaged in light work with machinery, the CO2 production rate is 0.5 liters per minute as shown in Figure 2.4

Figure 2.4: Internal body metabolism data [3]

To dilute the amount of CO2 in the room will depend on the amount of fresh air supplied

Table 2.1: The impact of CO2 concentration [1]

CO 2 concentration, ppm Impact level

>40000 Extremely toxic and severely oxygen-deprived air environment

>5000 Highly toxic and severely oxygen-deprived, can endure a maximum of 8 hours

2000 – 5000 Headache, drowsiness, poor concentration, increased heart rate, mild nausea

1000 – 2000 Symptoms of drowsiness and breathlessness appear, …

500 – 1000 Normal level in occupied spaces

From Table 2.1, the fan control model will operate in two modes: automatic and manual

- The system will activate when the CO2 concentration exceeds the threshold of 500ppm

- The supply fan will operate based on the CO2 concentration measured in the room

- The exhaust fan will operate at maximum capacity when CO2 is detected in the room

- The system will turn off when the CO2 concentration returns to the permissible level

- The system will be controlled directly on the Web, allowing for on/off switching and frequency adjustment.

Calculating the necessary parameters for the model

According to Appendix G and Appendix H of TCVN 5687:2010 [5], the fresh air supply volume in the room is determined by the formula:

- L is the air supply flow rate (m3/h).

- m is the air exchange multiplier (times/hour), for a laboratory, m

- V is the volume of the room (m3).

The fresh air flow rate needed for the GE room:

Choose a Deton axial duct fan with an air flow rate of 6640 m3/h and a power of 1.1 kW

The fresh air flow rate needed for the model:

Currently, there is no fan type available on the market that can meet the calculated air flow rate Therefore, the proposed solution is to use a frequency-controlled inverter for a fan with higher specifications (Detailed fan specifications will be provided in Appendices 6 and 7).

2.4.2 Wind speed calculation when passing through the air vent:

Based on the 2019 ASHRAE HANDBOOK [4], the maximum allowable speed when exiting the air vent will depend on the noise level specified for each room

Figure 2.5: Table of HVAC-related background noise design guidelines [4]

From Figure 2.5, for the laboratory room, the group chose the overall pressure level approximately according to weight A because this weight conforms to the lowest frequency sensitivity at the human ear Due to this, weight A is often used more to avoid risks to the human ear Therefore, the average noise level for the room will be 40dB

Figure 2.6: The recommended average air outlet velocity

15 Based on the selected noise level above and Figure 2.6, the corresponding average air velocity at the fan outlet is 2.8m/s

Based on the selected noise level above and Figure 2.6, the corresponding average air velocity at the exhaust fan is 3.4m/s

2.4.3 Selecting the air vent location for the model:

Based on ASHRAE 62.1 – 2016 standard [3], divide exhaust air into 4 categories:

Type 1: Air with low pollutant concentrations, low sensory irritation intensity, and no unpleasant odor

Type 2: Air with moderate levels of pollutants, mild sensory irritation, or slight unpleasant odors (Type 2 air also includes air that is not necessarily harmful or uncomfortable but is not suitable for circulation into spaces used for different purposes)

Type 3: Air with significant levels of pollutants, significant sensory irritation, or strong unpleasant odors

Type 4: Air containing smoke or very strong, unpleasant odors, or containing particles, biological pollutants, or hazardous gases at levels high enough to be considered harmful

Typically, a laboratory would be categorized as type 4 exhaust air, however, in some cases, consideration and assessment may be made to classify it into lower categories Therefore, the GE room will be classified as type 2 exhaust air to match the actual conditions of the room

The closest distance between the edges of the two supply air vents and the exhaust air vent of the GE room will be 3 meters

The closest distance between the edges of the two supply air vents and the exhaust air vent of the model will be 0.225 meters

Figure 2.7: The design drawing of the air vent positions

CONSTRUCTION OF THE MODEL AND DESIGN OF

Construction of the BMS Monitoring Model, Operation of the

3.1.1 Block Diagram of the BMS Model

The diagram illustrates the connection between elements in the BMS system model as shown in Figure 3.1 and Figure 3.2

Figure 3.1: Block diagram of the BMS model

Figure 3.2: Single-line diagram of the BMS model

- The Delixi EM60 inverter is powered by a single-phase 220VAC supply and controls the Auramax VP4 supply fan

- The IG5A inverter is powered by a 3-phase 220VAC supply to control the Hongke 130FLJ5 exhaust fan

- The VELT-W-CO2-I4 CO2 sensor is powered by 24VDC

- The BCU PNTECH is powered by 24VDC

- Utilizing a web interface on a computer to monitor and operate the model

- The central control device BCU will directly gather and exchange information from the DDC digital control devices, while also receiving and storing data in software for monitoring and control purposes

- DDC - C46 receives data from the BCU unit and operates the Delixi EM60 frequency inverter to control the Auramax VP4 supply fan along with the IG5A frequency inverter controlling the Hongke 130FLJ5 exhaust fan

- The VELT - W - CO2 -I4 CO2 sensor monitors and measures the CO2 concentration in the room, then sends signals to the DDC - C46 unit

3.1.2 Wiring diagram for the BMS mode

Figure 3.3: Wiring diagram for the BMS model

The BMS system is used to monitor and control two single-phase and three- phase fan motors powered from the power source This system is controlled and operated through monitoring software on a computer connected to the internet Within the system, a BCU device is used as the central control unit, tasked with directly gathering and exchanging information from the DDC digital control devices The DDC - C46 digital control unit is used to regulate devices within the model, including the single-phase Delixi EM60 frequency converter and the three-phase IG5A frequency converter Additionally, it sends monitoring data from the VELT-W-CO2-I4 CO2 sensor to the central control unit BCU The CO2 sensor is tasked with measuring the CO2 concentration in the room and sending signals back to the DDC

20 The Delixi EM60 and IG5A frequency converters receive commands from the DDC to perform actions such as stopping, running at preset frequencies

With this BMS system, managing and operating single-phase and three-phase fan motors becomes more automated and efficient Simultaneously, it monitors parameters such as CO2 concentration in the room to ensure the best working environment

Step 1: Inspect the equipment and proceed to connect the devices together

- Check the functionality of each type of equipment to ensure no unforeseen issues occur and to have timely repair or replacement solutions available

- Since the model employs 2 single-phase and 3-phase 220VAC fan motors, the power source used will be a 220VAC alternating current source

- Use an AC/DC converter to switch from a 220VAC source to 24VDC

- The central control device BCU, with a 24VDC input voltage, can directly draw power from the aforementioned AC/DC converter Additionally, both DDC devices and the VELT-W-CO2-I4 sensor are connected to this power source

Figure 3.4: Power supply for devices Step 2: Connect the BCU to the DDC - C46 digital control unit

- Connect the A+ and B- terminals of the DDC to the A+ and B- terminals of the BCU for MODBUS RTU communication via RS485 signals, allowing connection to the BMS

- Use shielded RS485 cable to connect the BCU to the DDC – C46, as shown in Figure 3.5

Figure 3.5: Shielded twisted-pair RS485 cable with aluminum foil mesh

Figure 3.6: Connect the A+ and B+ pins of the DDC to the A+ and B+ pins of the

Step 3: Connect the DDC to the control devices

- The UI01 terminal of the DDC is connected to the VELT-W-CO2-I4 CO2 sensor

- The UI05 terminal of the DDC is connected to the Auto mode switch of the supply fan

- The UI06 terminal of the DDC is connected to the Manual mode switch of the supply fan

- The UI09 terminal of the DDC is connected to the Auto mode switch of the exhaust fan

- The UI10 terminal of the DDC is connected to the Manual mode switch of the exhaust fan

- The NO01 terminal connects to the COM terminal of the single-phase inverter

- The NO02 terminal connects to the DI1 terminal of the single-phase inverter

Figure 3.7: Connect the pins for the DDC-C46 Step 4: Connect the single-phase and three-phase motors to inverters

- Use 2 out of the 3 output terminals of the inverter U, V, W, to connect to the single-phase motor

- Use the 3 output terminals of the frequency converter, U, V, W, to connect to the three-phase motor

Figure 3.8: Connect motors to inverters Step 5: Install the ceiling panel for the model

- Based on the calculated parameters and considering the real-world model, plywood material would be a robust and durable choice to withstand the weight from the exhaust and supply fans

Figure 3.9: Ceiling panel in the actual model Step 6: Install the electrical panel

- After completing the wiring design, the devices need to be neatly arranged inside the electrical panel

- The electrical panel used has dimensions of 30x40cm, with the necessary devices for the model mounted inside the panel, including:

Figure 3.10: Arrangement of devices in the electrical panel

Figure 3.11: The electrical panel after completion

Complete the hardware installation of the BMS model for monitoring

The Delixi EM60 frequency converter is a single-phase converter with an input voltage of 220VAC and a frequency of 50/60Hz, as labeled in Figure 3.12

Figure 3.12: The label of the Delixi EM60 frequency converter

Since this is a single-phase 220VAC frequency converter, the motor connected should also be a single-phase 220VAC motor (here it is the Auramax VP4 supply fan) The process of configuring the inverter is illustrated in Figure 3.13, and the detailed configuration parameters of the inverter are performed in Table 3.1 after connecting the device to the inverter

Figure 3.13: The procedure for configuring the Delixi inverter

Table 3.1: Configuring the Delixi EM60 inverter

Function code Function name Setting scope

P0.0.03 Option of operation control mode 1: Terminal control

P0.0.04 Option of A Frequency Source 3: External Terminal VF1

P2.0.00 Di1Terminal Function 1: Forward (FWD)

P2.0.12 UP/DOWN Terminal Change Rate 01.000

The process of installing the inverter:

To install the first frequency converter, supply power to the 220VAC frequency converter, and it will display as shown in Figure 3.14

Figure 3.14: Interface during inverter startup

Press the MODE button to enter the inverter setup menu, and after pressing, the frequency converter will display as shown in Figure 3.15

Figure 3.15: After pressing the MODE button

Press the >> button to select the digit position to be changed, then press the up or down button to select the number for configuring the inverter based on the manufacturer's instructions table

After finishing the lookup and selecting the function code, press ENTER to edit The screen will display as shown in Figure 3.16

Figure 3.16: The parameter that needs to be adjusted

To edit, press the up or down button Once you have selected the appropriate value, press ENTER to complete Upon success, the screen will display the next function code as shown in Figure 3.17

Figure 3.17: After successfully setting the parameters

After completing the setup, press the MODE button to return to the main screen

The procedure for configuring the iG5A inverter is performed as shown in Figure 3.18

Figure 3.18: Configuration process for the iG5A inverter

Assign register address PID Multi-function input

35 Firstly, configure the motor parameters for the inverter with the “Functions” as listed in Table 3.2 Next, configure the RS485 communication for the inverter with the process as shown in Figure 3.19 and set the “Functions” as listed in Table 3.3 a Setting up the parameters of the engine

Refer to the engine catalog and input the parameters into the variable frequency drive according to the 'Functions' specifications as stated in the manufacturer's catalog

H34 No-load current of the motor 0.27

The Modbus configuration process for the iG5A inverter is carried out as depicted in Figure 3.19

Figure 3.19: Modbus configuration process for the iG5A inverter

The configuration of the RS485 communication for the inverter is performed as outlined in Table 2.2

Address Baudrate Parity Stop bit Address in resgister

Table 3.3: RS485 Communication Parameter Settings

DRV Select RS485 control mode 3

FRQ Set the frequency via RS485 7

I59 Select Modbus-RTU communication protocol 0

I60 The address of the inverter for RS485 communication

(choose one value from 1 to 250)

I61 Select the baud rate = 9600 [bps] 3

I62 Run at the frequency before signal loss 0

I63 Time for the inverter to determine if there is an input frequency or not

The process of installing the inverter:

Press the left arrow key to select the H value, then press the up arrow key to choose the desired function Next, press the Enter key to set the value for the function The screen will display as shown in Figure 3.20

Figure 3.20: Set the value of function H

Press the left arrow key to select the I value, then press the up arrow key to choose the desired function Next, press the Enter key to set the value for the function

The screen will display as shown in Figure 3.21

Figure 3.21: Set the value of function I

Press the left arrow key to select the Frq value, then press the up arrow key to choose the desired function Next, press the Enter key to set the value for the function The screen will display as shown in Figure 3.22

Figure 3.22: Set the value of function Frq

Press the left arrow key to select the dru value, then press the up arrow key to choose the desired function Next, press the Enter key to set the value for the function The screen will display as shown in Figure 3.23

Figure 3.23: Set the value of function Frq

3.2.3 Configure the DDC - C46 using the DDC Configuration software

Step 1: Power up the DDC - C46

In the system, to power up the DDC - C46, a 24VDC source is used and connected to the 24VAC IN and GND terminals within the Power Input section of the device When the device is powered on, the first seven-segment LED will light up green, and each segment will cycle through This indicates that the device is functioning normally If this seven-segment LED does not cycle through, it indicates that the

41 device has encountered an error (hang) Additionally, the first LED also functions to display input values from 1 to 12, shown in green The remaining seven-segment LEDs on the device are red and are used to display values returned from sensors or to display configured object values, such as speed, address, etc

Step 2: Set up object values for the DDC - C46

On the device, there are buttons to perform the following functions:

- Button < >: Used to change the values of the configured objects When this button is pressed, users can adjust the parameters as desired

- Button : The function of this button is to toggle between the objects to be displayed or the objects to be configured, such as addresses, speeds, etc By pressing this button, users can switch between items to access and adjust relevant information

Display d009: This display, referred to as "d009," is shown using a 7-segment LED display The first 7-segment LED displays the letter "d," denoting the Baudrate speed of the device, measured in bps (bits per second) For example, if the Baudrate speed value set on the DDC is 9600 bps, the display will show "009" on three red 7- segment LEDs

Display of 4 LEDs showing "E003": On this display, the first 7-segment LED shows the letter "E," representing the MAC address of the DDC-C46 "003" represents the MAC address currently used in the model

Figure 3.25: Setting the MAC address

Display of 4 LEDs showing "F001": On this display, the first 7-segment LED shows the letter "F," representing the operating mode of the DDC-C46 device Mode

"1" represents the Modbus standard, while mode "0" represents the BACnet standard

In the model, the DDC device is operating in Modbus mode, and the display value is

Figure 3.26: Set up the communication protocol Step 3: Use the DDC Configurator software

Use USB CH340 to connect the DDC to the computer as shown in Figure 3.27

Figure 3.27: Connect the computer to the DDC using a USB RS485 port

After connecting the computer to the DDC, start the Configurator software for DDC - C46 The startup interface of the software will appear as shown in Figure 3.28

Figure 3.28: Screen of DDC Configurator software configuration

The first parameter frame is "Connection," which is the first setting that needs configuration The "Comport" item is used to select the appropriate COM port for connection to the computer, here it is COM6 The "Baudrate" item is set to 9600, and the "Address" item is set to 3 to match the setup on the DDC Finally, the "Protocol" item is set to Modbus

Figure 3.29: Configure the DDC to connect to the computer

When the screen displays as shown in Figure 3.30, to determine if the program is ready, check the Software Status frame as depicted in the image

Continuing with the Settings frame, select "Auto Save" mode to automatically save values during operation In the "Control From" section, choose "Remote+Main" to enable remote control and direct wiring control simultaneously

Figure 3.31: Setting the control mode for the DDC Step 4: Configure the inputs and outputs of the DDC

Interface Design

53 There are 2 main methods to connect to the BCU:

- WiFi mode: BCU broadcasts WiFi for accessing software via IP

- LAN Network Mode: Allows configuration of Router IP address and IP for BCU

The main method that the team uses is utilizing WiFi

After successfully connecting to the WiFi, proceed to open any web browser to log in to the BCU software

Figure 3.43: The login interface Select the "Settings" section to access the "System Configuration," where you can configure the IP for BCU to match the IP of the Router

Figure 3.44: The IP configuration interface for BCU

- Device IP: Change the last value to ensure it does not conflict with other devices, with values ranging from 0 to 255 (192.168.1.254)

- Default Gateway: Enter the IP address of the Router: 192.168.1.1 b Overview of the BMS Control Software interface:

Figure 3.45: Summary of the tools in the BMS Control Software

The BMS Control Software comprises the following sections for managing and operating the BMS (Battery Management System):

- Dashboard Tab: Provides an overview of the entire system, aggregating metrics such as number of buildings, quantity of devices, operational schedules, etc

- Tab Building: The main interface allows for the initialization of workspaces to monitor parameters and control connected devices This interface is customizable, enabling users to tailor it according to their specific job requirements

- Tab Device: This section is for setting up devices and their addresses:

• Device list: Allows for creating devices and configuring installed devices

• Point list: This is where you initialize and configure a specific data value Each device can have multiple data points depending on usage needs

- Tab Control Group: This section allows you to group devices together and operate them collectively You can define device groups and perform operations such as turning on/off, adjusting settings for all devices in the group easily

- Tab Schedule: This section allows you to set schedules for device operations

- Tab Data Log: This section allows for storing time-series data to help users analyze metrics and display visual graphs

- Alarm: This section reads data from various points, compares them with preset thresholds, and allows for alert notifications via SMS or email if thresholds are not met

- Setting: This section allows you to configure settings for font type, font size, colors, images, and units of measurement within the software

The sections above provide comprehensive functions and capabilities for managing, operating, and monitoring the BMS (Battery Management System) through the BMS Control Software c Steps to build a control system on the BMS Control Software

Step 1: Set up the units

- To create units, select "Setting" ➔ "Unit," then start initializing the name, value, and display position of the unit ➔ "Add new." The units, once initialized, will appear in a statistics table as shown in Figure 3.46

Step 2:Set up the Device list

To create a device, go to "Devices" ➔ "Device List" ➔ "Add new." The configuration table for the device parameters will appear as shown in Figure 3.47

Figure 3.47: Configure the parameters for the DDC device

Mục Title: Enter the name of the device to be used

• MOD485: The abbreviation of the Modbus communication protocol over RS485 data transmission line is "Modbus RTU"

• N: No Parity (No parity check performed.)

After creation, the devices will appear on a table shown in Figure 3.48 for easy monitoring

Figure 3.48: The list of devices Step 3: Point list setup

To create a device, go to Devices -> Point List -> Add new The configuration table for device parameters will appear as shown in Figure 3.49

Figure 3.49: Setting up CO2 sensor points

59 Title: Enter the name of the point to be controlled

Description: Enter a description for the point to be controlled

Device: Select the device that contains this Point

Access Type: Allow read and write data or write-only data

Value: If it is a monitoring point, no input is required If it is a control point, enter the appropriate value

Default Value: Set the default parameter when initializing the Point

Figure 3.50: Setting up Frequency of Exhaust Fan points

Title: Enter the name of the point to be controlled

20: the parameter for setting the frequency of the variable frequency drive

61 Access Type: Allow read and write data or write-only data

Figure 3.51: Setting up Frequency of Supply Fan points

Figure 3.52: Setting up Speed of Exhaust Fan points

63 Title: Enter the name of the point to be controlled

Figure 3.53: Setting up output current points

65 Value: If it is a monitoring point, no input is required If it is a control point, enter the appropriate value

Figure 3.54: Setting up output voltage points

The list of points used in the BMS model is detailed in Appendix 2

Step 4: Data processing with Node-RED

Node-RED is a programming tool that allows users to drag and drop function blocks or write code in JavaScript Here, values read from devices such as variable frequency drives may need scaling adjustments, and Node-RED facilitates this data processing task

The steps are as follows:

• To set up a data point from a virtual device to store a new value, follow these steps using Node-RED:

• To retrieve the IDs of 2 points (for example, Point Run Command and Virtual Run) in Node-RED

Table 3.5: Name, ID, QR code of Data Points

Set Point DO 01-CO2 6650574df5db700738830a49

• Access Node-RED Select the "System Programming" section A login prompt window appears as shown in Figure 3.55

Figure 3.55: Login form for Node-RED

• To proceed, use the function block in Node-RED

The Inject node allows you to trigger a flow at the beginning of each data processing branch It offers various features, including scheduling flows at regular intervals Configure it as shown in Figure 3.57 to execute a loop processing every second, triggering data injection once

Figure 3.57: Configuration of the Inject node

The HTTP In: node functions to retrieve data values from active Points, allowing assignment of values to Points based on device IDs

Figure 3.58: The HTTP In node

69 Enter the link into the HTTP In node to fetch data as shown in Figure 3.59.

Figure 3.59: Configure the HTTP In node

Retrieve data using the following syntax: http://controlbms:3000/points/point_value?point_idd210e1cb2783006f39b7a 8b

Assign data using the following syntax: http://controlbms:3000/points/update_points?64210b6cb2783006f39b7a6f={{{ payload}}}

70 The Function node allows execution of JavaScript commands The algorithm scales data inversely to match the desired values as shown in Figure 3.60

Figure 3.60: Configure the Function node

Set up a single data processing branch Trigger an injection into the 'Virtual Run' tag every second, with values passing through a scaling command to adjust them as

71 desired, then assign them to the 'Run Command' tag Complete one simple data processing cycle The structure is as shown in Figure 3.61

Figure 3.61: The data processing flow between two points

From there, implementing the remaining parameters yields the algorithmic branch node as depicted in Figure 3.62

Figure 3.62: The system-wide data processing of Points

The web page diagram is illustrated as Figure 3.63 Specifically:

After logging in, the homepage appears first In the homepage section, there are

2 links leading to 2 pages: Monitoring and Control In the 'Monitoring' section, monitoring data is retrieved from a specific database, in this case, Firebase This data is used to adjust system coefficients and generate alerts These alerts influence the

72 control process to prevent damage to the system In the 'Control' section, signals are sent to the Firebase database, which then transmits these signals to operate the system."This setup describes a typical architecture where Firebase serves as both the data source for monitoring and the communication channel for control signals in a web-based system

Figure 3.63: Website diagram a) Login interface

Figure 3.64: Login interface b) Control interface

The goal of developing the control interface aims to create a modern system capable of manual communication between operators and devices, leveraging connectivity to the Internet for seamless interaction

The content of the "Control" page is divided into 2 sections: the Exhaust Fan Control section and the Supply Fan Control section

Firstly, the exhaust fan control section: This allows setting frequency parameters, PID settings, and switching between the Auto and Manual modes Specifically, as shown in Figure 3.65

Figure 3.65: Control panel for the exhaust fan

74 Next is the supply fan control section: This allows setting the ON/OFF of the supply fan and switching between the Auto and Manual modes Specifically, as shown in Figure 3.66

Figure 3.66: Control panel for the supply fan

To set parameters and control the system remotely, the website needs to send setting values and signals to the Firebase database From there, the central processing unit will receive parameter values and control signals to manage the system

How to send values from the website to Firebase: c) Monitoring interface

The goal is to develop a monitoring interface, creating a dedicated platform for monitoring and data collection This will enable the implementation of optimal measures for the system

The content of the "Monitoring" page is divided into blocks Each block contains a name, value, and an icon symbolizing a specific parameter Specifically, as shown in Figure 3.67

Figure 3.67: The content of the "Monitoring" page

Next, these blocks allow users to "click" to view detailed parameters at each moment and generate daily reports to assess the system's status, as shown in Figure 3.68

Figure 3.68: Monitoring the detailed parameter "Speed"

To monitor the values of a parameter, first, you need a place to store those parameter values Then, you can use a programming language specifically JavaScript in this case to retrieve the parameter values and display them on a web page

Step 1: Log in to the website https://firebase.google.com, then sign in with your

Google account After logging in, the interface appears as shown in Figure 3.69

Figure 3.69: Firebase interface after logging in Step 2: Create a Project

Figure 3.70: Create a project Step 3: Name your project

Figure 3.71: Name your project on Firebase Step 4: Enable Google Analytics and select "Configure Google Analytics

Figure 3.72: Enable Google Analytics to access the project

Figure 3.73: Select "Configure Google Analytics

After creating the project, the interface will look like Figure 2.61

Figure 3.74: Interface after successful project creation

To enable a webpage to transmit, receive, and continuously update parameter valuesover time, you need to create a Realtime Database within your project

Step 1: Click on "Create Database" and follow the steps as shown in Figure 3.76

Figure 3.76: Location for storing Realtime Database Step 2: Select security rules

In security rules, there are typically two security modes to choose from based on your usage needs

80 Start in locked mode": Data will be private Read/write access for client devices will be granted based on security rules

Start in test mode": Data is open to client devices for read/write access However, the owner device needs to access frequently within 30 days to maintain security rules in this mode

Figure 3.77: Choose the mode for security rules

Step 3: Click "Enable" to complete the process of creating Realtime Database and add additional data nodes for use

Figure 3.78: Interface upon completing the Realtime Database creation

Figure 3.79: Nodes created for usage

How to retrieve parameter values from Firebase and display them on a webpage

Step 1: Declare Firebase in the JavaScript file

Step 2: Use the following command to retrieve parameter values from Firebase

OPERATION OF THE MODEL AND RESULTS EVALUATION

System Operation Flowchart

The process of operating the system model for monitoring and controlling CO2 levels is conducted as shown in Figure 4.1 flowchart

Figure 4.1: Flowchart of the process for operating the CO2 monitoring and control system

- Begin block: Supply power to the BMS system If unsuccessful, return to the starting position

- If successful, then check the safety of the model: insulation, short circuit

- After meeting the requirements, there will be two branches with two modes: Auto and Manual

- In Manual mode: Log in to the website interface Then, there will be two modes for control and monitoring Next, evaluate the system and end the program

- Set Auto mode: Introduce a quanity of CO2 into the model Monitor parameters through the inverter screen Next evaluate the system and end the program

Operation Objective: To control and monitor the CO2 monitoring and control system in two main modes: Auto mode and Manual mode.

System check

To ensure the safety of the system before operation, a comprehensive check of the connecting devices is necessary This includes checking the insulation resistance of the cabinet base, verifying power circuit shorts to ensure system safety Optionally, grounding wires (PE) can be connected to the cabinet to enhance operational safety (not elaborated here, as grounding device is not connected).

Operating the Model in Auto Mode

Step 1: At the control panel, switch the toggle switch (Manual /Auto) to Auto mode Check the status on the DDC (Direct Digital Controller): the input values at terminals 5 and 9 should both read "1" to confirm operation

Figure 4.2: Selecting Auto Control Mode

Figure 4.3: Input terminals 5 and 9 shows the value "1"

Step 2: Introduce a sufficient amount of CO2 into the model so that the CO2 concentration in the sensor increases Check the status at the DDC, specifically input terminal 1

Step 3: When the CO2 concentration exceeds the permissible level, the supply fan system starts operating to dilute the CO2 within the model The exhaust fan will operate at full capacity to process and remove CO2 to ensure the airflow in the room space is refreshed and CO2 is effectively extracted

Step 4: Once the air in the room is free of gas, the system will resume normal operation.

Operating the Model in Manual Mode

Step 1: At the control panel, switch the toggle switch (Manual /Auto) to Manual mode Check the status on the DDC (Direct Digital Controller): input terminals 6 and

10 should both read "1" to confirm operation

Figure 4.4: Selecting Manual Control Mode

Figure 4.5: Input terminals 6 and 10 shows the value "1"

Step 2: Log in to the monitoring interface on the website

Access the Visual Studio Code software

Figure 4.6: The interface of Visual Studio Code

On the toolbar, select "Run," then choose "Run Without Debugging" to start the website

Figure 4.7: Select "Run Without Debugging" to launch the website

Figure 4.8: The login interface of the website Step 3: Proceed to control and monitor through the interface

To configure the settings for running and operating the system as desired, navigate to the "Ventilation System Control" section on the "BMS Monitoring and Control System Model" page Upon entering the page, the interface will appear as shown in Figure 4.9

Figure 4.9: The ventilation system control interface on the website

To operate the fan system in Manual mode, switch to the Manual button in the

"Supply Fan" and "Exhaust Fan" sections as shown in the Figure 4.10

Figure 4.10: When configured in Manual mode

In the "SET CO2" section under automatic mode, you will set the CO2 concentration value in the room to control the activation and deactivation of each supply and exhaust fan When the CO2 concentration exceeds this set value, the fans will activate, and when it falls below this threshold, the fans will deactivate, as shown in Figure 4.11

Figure 4.11: Setting the fan below the CO2 concentration threshold in the room Next, in the "SET ON SUPPLY FAN" section, to control the activation and deactivation of the supply fan as desired

Figure 4.12: Perform the ON/OFF operation to turn the supply fan on or off

You can control the frequency of the exhaust fan as needed by changing the value in the "SET FREQUENCY EXHAUST FAN" section, as shown in Figure 4.13

Figure 4.13: Set the running frequency for the exhaust fan

Furthermore, the "FREQUENCY SUPPLY FAN" and "FREQUENCY EXHAUST FAN" sections are used to monitor the frequencies of the fans in the system, as depicted in the Figure 4.14

Figure 4.14: Monitor the frequencies of the fans in the system

In addition, you can set PID parameters for the system as shown in the figure 4.15

Figure 4.15: Set the PID parameters

Here, the information is divided into blocks as shown in Figure 4.19 Clicking on each block will provide detailed parameters through line charts and bar graphs displaying parameter values over time

Figure 4.16: Monitoring basic parameters on the web interface

The "CO2" block displays the concentration of CO2 supplied into the room, as shown in the Figure 4.17

Figure 4.17: Monitoring CO2 concentration The "Voltage" block displays the voltage of the exhaust fan, as shown in the Figure 4.18.

Figure 4.18: Monitoring the voltage of the exhaust fan

The "Current" block displays the current of the exhaust fan, as shown in the Figure 4.19.

Figure 4.19: Monitoring the current of the exhaust fan

The "Exhaust Fan" block displays the speed of the exhaust fan, as shown in the Figure 4.20.

Figure 4.20: Monitoring the speed of the exhaust fan

The "Compare CO2/Exhaust Fan" block displays the correlation between CO2 concentration and the speed of the exhaust fan, as shown in the Figure 4.21.

Figure 4.21: Monitoring the correlation between CO2 concentration and fan speed

System Evaluation

After testing and fine-tuning the system, the CO2 concentration is controlled below 1000 ppm (considered the best air quality level) Here are the operational results of the model over a period of time, as shown in Figure 4.22

Figure 4.22: A chart depicting the relationship between CO2 concentration and fan speed under high occupancy The chart illustrates the relationship between fan speed and CO2 concentration measured over a period of time In this scenario, the supply and exhaust fan speeds adjust based on the CO2 concentration values detected inside the model A clear trend shows that the CO2 concentration remains below the permissible threshold of 1000 ppm, affirming that the project has successfully achieved its initial objectives.

CONCLUSION

Conclusion

The project "Application of BMS for monitoring and operating frequency converter controlled ventilation fans to control CO2 levels" by our team has achieved the following results:

• Understanding the fundamental design principles of a ventilation system, which enabled the calculation of necessary parameters for the model

• Establishing communication between CO2 sensors, DDC (Direct Digital Controller), BCU (Building Control Unit), frequency converters, etc Understanding and implementing accurate connections between devices using appropriate communication protocols

• Designing and implementing hardware components for the model, including operating the Delixi EM60 and IG5A frequency converters to control two fan motors for exhaust and supply air

• Designing a web interface for monitoring and controlling the system.

Future Work

Given that the model currently operates within the confines of a single room and focuses solely on controlling CO2 levels, to expand and further develop this project:

• In practical applications, especially in laboratories, there are typically three types of fans: supply, exhaust, and recirculation To scale up the model, it would be essential to include exhaust fans as well

• Additional sensors for temperature, humidity, smoke, and dust should be integrated to enhance the accuracy and efficiency of fan operations

• The current model utilizes Node-RED and an application on a mobile platform for monitoring sensor parameters It would be beneficial to develop a dedicated mobile application for independent operation and monitoring

[1] ThS Trần Minh Ngọc, TS Nguyễn Văn Hạp, “HVAC Ứng dụng cho nhà cao tầng”, Nhà xuất bản đại học quốc gia TP Hồ Chí minh, 220 trang

[2] Nguyễn Đức Lợi, “Giáo trình Hệ thống điều hòa không khí”, Nhà xuất bản giáo dục Việt Nam, 339 trang

[3] ANSI/ ASHRAE Standard 62.1 – 2016, Ventilation for Acceptable Indoor Air

[4] 2019 ASHRAE HANDBOOK, Heating, Ventilating and Air-Conditioning

[5] TCVN 5687:2010, Thông gió – Điều hòa không khí Tiêu chuẩn thiết kế, Nhà xuất bản xây dựng

[6] Hồ Đức Anh Toàn, Tô Đình Nhật Quang, “Ứng dụng BMS giám sát, vận hành biến tần điều khiển động cơ không đồng bộ bà pha và máy phát điện đồng bộ”, Đồ án tốt nghiệp 2022

[7] Honeywell, Engineering Manual of Automatic Control for Commercial

[8] Delixi Electric, CDI-EM60 Series Frequency Inverter Instruction Manual [9] Winsen Sensor, Infrared CO2 Sensor Module (Model: MH-Z19B)

[10] Công Ty Cổ Phần Công Nghệ PNTECH, Cataloge BCU Building Control

[11] Công Ty Cổ Phần Công Nghệ PNTECH, Cataloge Direct Digital Controller

[12] Arduino Documentation, Arduino ® UNO R3 Datasheet

Configuration of Data Points in BMS Control Software

Appendix 1: Configuration of Data Points in BMS Control Software

Table PL1.1: Configuration of Data Points in BMS Control Software title slug excerpt access_type

Set Point DO 01-CO2 set-point-do-01-co2 3|HR|350|1|W write

Set Override AO 01 set-override-ao-01 3|HR|612|0|W write

Set point AO 01-CO2 set-point-ao-01-co2 3|HR|614|1|W write

AUTO sup Fan (UI09) auto-sup-fan-ui09 3|IR|17|1|R read

Manual sup Fan (UI10) manual-sup-fan-ui10 3|IR|19|1|R read

Auto exhaust Fan(UI05) auto-exhaust-fanui05 3|IR|9|1|R read

Fan(UI06) manual-exhaust- fanui06 3|IR|11|1|R read

Freq exhaust Fan freq-exhaust-fan 3|IR|87|0|R read

Freq supply Fan freq-supply-fan 3|IR|81|0|R read output current output-current 3|HR|1016|0|R read output voltage output-voltage 3|HR|1022|0|R read

RPM Exhaust FAN rpm-exhaust-fan 3|HR|1028|0|R read

Set Override DO 01 set-override-do-01 3|HR|348|0|W write

Override Enable AO 01 override-enable-ao-

Override Enable DO 01 override-enable-do-

Variable Frequency Drive Delixi EM60

Figure 3: Connection Diagram of Delixi EM60 Variable Frequency Drive

Table PL2.1: Delixi EM60 Variable Frequency Drive Terminal Connections

R, S Input voltage supply for the variable frequency drive

U, V, W Output voltage supply for the motor

DI1, DI2, DI3, DI4 Digital input terminals

TIA, TIB, TIC Multi-function relay output

Variable Frequency Drive IG5A

Figure 4: Connection Diagram of IG5A Variable Frequency Drive [8]

- Utilizes sensorless vector control, PID algorithm, and ground fault protection

- Can handle 150% overload for 60 seconds

- Manual setup and operation via built-in buttons or control through RS485 communication protocol

Table PL3.1: IG5A Variable Frequency Drive Specifications

Figure 5: IG5A Variable Frequency Drive Pinout Diagram

• MO: Multi-function output terminal

• MG: Ground terminal for external power supply

• VR: Power supply for external potentiometer

• AM: Analog output signal (Voltage: 11V, Current: 10mA)

CO 2 sensor VELT-W-CO2-I4

The VELT-W-CO2-I4 CO2 sensor is a type of sensor that measures carbon dioxide concentration with a 4-20mA output

Figure 6: VELT-W-CO2-I4 CO2 Sensor [9]

Table PL4.1 Specifications of VELT-W-CO2-I4 CO 2 Sensor

Figure 7: Wiring diagram of the CO 2 sensor VELT-W-CO2-I4

- Vin, GND: Supply DC power 10-30V to the CO 2 sensor

- PWM pin: Outputs PWM signal.

Hongke 130FLJ5 fan specifications

104 Main specifications of the Hongke 130FLJ5 fan

Auramax VP4 fan specifications

Main specifications of the Auramax VP4 fanModel: VP4