Simulation Model of Air Handling Unit (AHU) System

The Air Handling Unit (AHU) simulation model represents a sophisticated system comprising multiple interconnected components. The valve model regulates airflow using PID control algorithms to maintain precise volumetric flow rates. The cooling coil model implements heat transfer equations to reduce air temperature through refrigerant evaporation. The heater model utilizes resistance heating elements with temperature feedback loops. The humidifier model employs steam injection or water spray mechanisms with humidity control logic. Finally, the sensor model integrates temperature and humidity sensors with data acquisition systems for real-time monitoring.

The valve model implements flow control algorithms using actuator position feedback and pressure differential calculations. It typically includes functions for damper positioning and airflow characterization based on duct geometry. The cooling coil model simulates heat exchange processes using NTU-effectiveness methods, calculating temperature differentials across the coil fins. The heater model incorporates thermal dynamics equations, simulating gradual temperature rise with time constants and heat capacity considerations.

The humidifier model implements mass transfer calculations for water vapor absorption, with control algorithms maintaining target humidity levels through proportional steam output. The sensor model includes signal processing routines for analog-to-digital conversion, noise filtering, and calibration offset compensation. Sensor data is typically processed through moving average filters to ensure measurement stability.

Collectively, these component models interact through coupled differential equations, forming a complete thermal-hydraulic simulation. The integrated system models transient responses to control inputs, environmental changes, and load variations, providing accurate predictive capabilities for HVAC system design and optimization.