Milestone #2

Task Breakdown:

1. Research

• Climate Control Requirements: Identify key factors affecting comfort and energy efficiency in residential and light commercial HVAC systems, including temperature, humidity, and airflow.

• Sensor Selection: Research the most accurate temperature and humidity sensors for real-time zonal monitoring.

• Communication Protocols: Evaluate reliable communication standards (e.g., RS-485, Wi-Fi, Zigbee) for seamless data transmission between sensors and the controller.

• Energy Efficiency Standards: Investigate industry standards such as SEER and EER to ensure compliance and optimize performance.

• Learn Necessary Skills: Learn how to use MCU boards for the project. 

2. MCU Choices

• Microcontroller Selection: Identify an MCU capable of managing multiple zones, interfacing with sensors, and processing control algorithms.

• Key Features: Evaluate connectivity, processing power, and pin configuration for compatibility with the selected sensors and actuators.

3. Software Development

• Initial Coding Setup: Decide on programming language and frameworks for the system's firmware and connectivity.

• Zonal Algorithm Design: Develop basic temperature regulation algorithms to optimize comfort and energy efficiency.

• RTOS Testing: Implement an RTOS to manage real-time data processing and system responsiveness.

4. Prototyping (Physical)

• System Layout: Design an initial layout, including the placement of sensors, actuators, and the central controller.

• Initial Assembly: Connect the MCU to sensors and dampers for individual testing.

• Temperature Control Simulation: Use heater pads to simulate zone-specific heating and ensure the controller adjusts outputs accurately.

• Airflow Control: Integrate motorized dampers for zonal airflow and test their responsiveness to control signals.

Project Plan:

1. Research

2. MCU Choices

3. Software Development

4. Prototyping (Physical)

5. Testing

6. Final Build

Core Concepts:

1. Centralized Control

• Centralized Monitoring: Enable monitoring of all zones from a single display or interface, whether local or cloud-based.

• Ease of Access: Support control through one simple thermostat or possible app.

• Zone Autonomy: Allow individual zones to operate autonomously based on preset parameters while reporting to the central system.

2. Sensor Integration and Placement

• Accurate Monitoring: Strategically place temperature and humidity sensors in each zone for precise readings and better zone management.

• Redundancy for Reliability: Include backup sensors to ensure continuous operation in case of failure.

• Data Storage: Maintain local storage of environmental data for trend analysis and troubleshooting, with optional cloud integration for remote monitoring.

3. User-Focused Design

• Simple Setup: Provide easy installation and setup with clear instructions.

• User-Friendly Interface: Incorporate intuitive displays and controls to adjust settings, view system status, and troubleshoot.

• Customizable Comfort: Allow users to set personalized temperature gradients and energy-saving modes for each zone.

4. Long-Term Data Use

• Trend Analysis for Improvement: Use long-term data trends to improve system algorithms and recommend maintenance schedules.

• Collaboration: Anonymously share system performance and energy data (with user consent) to aid research and development in energy efficiency and HVAC design.

Concept Exploration

1. Power Management

   • Investigated the use of standard power supplies versus modular, rechargeable battery packs for continuous operation.

   • Trade-offs: Rechargeable batteries provide flexibility during power outages but require more robust charging and monitoring circuits.

2. Microcontroller and Communication Interface Options

   • Explored high-performance microcontrollers with integrated features versus modular setups with additional peripherals.

   • Trade-offs: Integrated solutions save space and simplify the design but may limit scalability. Modular systems offer flexibility but increase the complexity of communication protocols.

3. Sensor Connectivity and Placement

   • Evaluated centralized versus distributed sensor configurations for temperature and humidity monitoring.

   • Trade-offs: Centralized setups simplify wiring but can reduce precision for zonal control. Distributed sensors provide localized readings but increase installation complexity.

4. Data and Control Interfaces

   • Considered implementing local-only control versus cloud-enabled systems for real-time monitoring and adjustment.

   • Trade-offs: Local control ensures data privacy but limits remote management capabilities. Cloud integration provides enhanced functionality but introduces potential data security challenges.

Selected Design

After analyzing technical and operational trade-offs, the following design approach was chosen:

1. Microcontroller with Integrated Communication Support

   • Features:

     1. High-speed processing to handle data from multiple zones.

     2. Robust communication with remote sensors and actuators.

     3. Expandable input/output capabilities for future scalability.

   • Benefits:

     1. Reduced board space by avoiding external communication modules.

     2. Simplified setup and maintenance.

2. Zonal Sensor Integration

   • Distributed sensors for each zone to provide precise environmental monitoring.

   • Selected sensors are durable, responsive, and compatible, ensuring reliability and easy data transmission.

3. User Interfaces

   • Local Control: A simple control system for configuration, monitoring, and manual adjustments.

   • Remote Monitoring: Optional cloud integration using MQTT for users to view and manage their systems remotely.

1. Temperature and Humidity Data Gathering

   • Remote sensors measure temperature and humidity from sensors 

   • Data is collected periodically based on pre-set intervals or changes exceeding a threshold

2. Communication with Central Controller

   • Remote devices send temperature/humidity data to the central controller via RS-485 communication

   • Data packets include sensor ID, temperature, and humidity

3. Data Processing at the Central Controller

   • The central controller receives, parses, and validates the data from remote devices

   • Data anomalies are filtered out using signal processing algorithms

4. Decision-Making 

   • Control algorithms determine which dampers to open or close and intensity and duration for heater pads in specific zones

5. Command to Actuators

   • Central controller sends control signals via RS-485 to:

     • Adjust dampers for airflow

     • Turn heater pads on/off or adjust PWM for specific heating levels

6. Real-Time Feedback and Optimization

   • Sensors continue to monitor changes in temperature and humidity after adjustments

   • Updated data is sent back to the central controller for refinement of decisions

7. Optional Cloud Reporting

   • System parameters and performance data are sent to the cloud via MQTT 

   • Users can monitor or adjust settings remotely through a cloud-connected application

1. Communication Issues (RS-485 Network)

• Problem: Noise or signal degradation in the RS-485 network can lead to data loss or corruption

• Workarounds:

  • Use proper termination resistors at the ends of the RS-485 bus to prevent signal reflection.

  • Implement CRC (Cyclic Redundancy Check) for error detection in communication.

2. Sensor Inaccuracy or Failure

• Problem: Sensors may provide inaccurate readings

• Workarounds:

  • Implement redundancy by deploying multiple sensors in critical zones.

  • Calibrate sensors regularly to maintain accuracy.

  • Use filtering algorithms to smooth out noise in readings.

3. Overlapping Zones or Conflicting Commands

• Problem: Zones may overlap, leading to conflicting commands 

• Workarounds:

  • Use a priority or weighting system to handle overlaps

  • Implement a conflict resolution mechanism, such as averaging temperature requirements for overlapping zones.

4. User Interface Challenges

• Problem: Users may find the system interface confusing or unintuitive

• Workarounds:

  • Design a simple and consistent UI with clear temperature setpoints and zone mappings

  • Provide quick access to key features like temperature override or mode changes

Testing the Zonal HVAC Control System

1. Sensor Accuracy

   • Connect each temperature and humidity sensor to the MCU and test using a serial monitor.

   • Cross-verify sensor readings with a calibrated reference device to ensure accurate data.

   • Test sensor response times to rapid environmental changes in temperature or humidity.

2. Zonal Control Validation

   • Test individual zones to ensure that dampers and heater pads respond appropriately to sensor inputs.

   • Simulate real-world conditions (e.g., one room heating up faster than another) to evaluate the system’s ability to adjust outputs dynamically.

3. Data Transfer

   • Monitor data transmitted from sensors to the MCU using the serial interface to confirm proper communication.

   • Test data logging in a local database and verify synchronization with the cloud for remote monitoring.

   • Confirm real-time updates to the user interface, ensuring all zone data displays correctly and promptly.

System Performance

1. Environmental Testing

• Operate the system in varied temperatures and humidity conditions to ensure reliability and accuracy.

• Check actuator and damper performance in extreme conditions to validate operational resilience.

2. Latency and Responsiveness

   • Measure the delay between sensor detection and system actuation for zone temperature adjustments.

   • Ensure the system meets real-time requirements for comfort and energy optimization.

Connectivity and Range

1. Communication

   • Verify data integrity over long cable runs to confirm the range and reliability of the communication.

   • Test robustness in different configurations, such as interference-prone environments.

2. Cloud and App Integration

   • Validate connectivity between the MCU and the cloud interface over Ethernet or Wi-Fi.

   • Test mobile app functionality, including real-time monitoring and zone control from a remote location.

Energy Efficiency Testing

1. Energy Usage Metrics

• Evaluate overall system energy consumption during typical operation.

• Run tests to verify the impact the the new system on energy savings.

Long-Term Tests

1. Reliability Over Time

• Run the system continuously for extended periods to detect issues with data transfer, actuator wear, or sensor drift.

• Log system performance and analyze trends to ensure consistent operation.