LabVIEW Based HVAC Building Management Energy Optimizer for Occupancy and Air-Quality Responsive Ventilation Control

Heating, ventilation, and air-conditioning (HVAC) systems contribute significantly to total buildingenergy consumption because conventional ventilation systems often operate continuously at fixed power levelsregardless of real-time spatial demand. This paper presents the design, hardware implementation, and graphicalvalidation of a low-cost, real-time HVAC Building Management Energy Optimizer that dynamically regulatesventilation based on room occupancy and environmental sensing. The hardware architecture utilizes an ESP32microcontroller as the central control unit, an HC-SR501 passive infrared (PIR) sensor for occupancy detection,an MQ135 analog environmental sensor, an L298N driver module for Pulse-Width Modulation (PWM) fan control,a 6 V DC geared motor representing the ventilation fan, and an SG90 servo motor serving as a motorized HVACairflow damper. Laboratory Virtual Instrument Engineering Workbench (LabVIEW) communicates with the ESP32via a USB serial (VISA) interface to provide graphical real-time data acquisition, parameter visualization, decisionmonitoring, and dynamic power/energy estimation. The system employs a rule-based control strategy whereoccupancy acts as the primary gate: when unoccupied, fan speed and damper position are set to 0% and 0°,respectively. Under occupied conditions, ventilation is scaled across three demand tiers—30% (30° damper), 60%(60° damper), and 100% (90° damper)—based on analog air-quality threshold boundaries. Experimentalvalidation confirms the full hardware-software execution chain, establishing an accessible, transparent prototypefor demand-controlled ventilation (DCV) and building energy optimization