MATLAB HVAC SIM

This group project involved the multidisciplinary modeling and simulation of a smart HVAC thermostat that integrates mechanical, electrical, fluidic, thermal, and chemical subsystems into a single control framework. Each subsystem was developed using first-principles equations and implemented in MATLAB, with actuator dynamics controlling dampers and fans, sensors providing real-time feedback, airflow modeled through duct networks, heat transfer governing indoor temperature, and CO₂ concentration representing indoor air quality. The system was coupled using a Lagrangian Differential-Algebraic Equation (LDAE) approach to capture interactions between subsystems and enforce physical conservation laws.

The simulation results shown in Figure 1 demonstrate how these subsystems interact during operation. Actuator displacement and velocity illustrate stable, well-damped mechanical control, which directly influences airflow rate through the duct system. Sensor voltage output reflects consistent feedback used by the controller to regulate system behavior. The indoor temperature and CO₂ concentration plots show system-level performance: temperature is driven toward a comfortable steady state, while elevated CO₂ levels trigger increased ventilation that reduces pollutant concentration over time. Together, these graphs validate that the integrated control strategy effectively balances thermal comfort and indoor air quality while maintaining stable and efficient system dynamics.

Figure 1: Graph Compilation

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