# Model-based prototype design, establishment and operation of ventilation system for underground gymnasium

## TL;DR

This paper presents a model-based ventilation system for underground gymnasiums that efficiently controls temperature and gas levels while saving time and cost.

## Contribution

The novel contribution is the development and application of a closed-loop control system with optimized parameters for ventilation in underground gymnasiums.

## Key findings

- Optimal parameters for the control system were determined using global parameter sensitivity analysis and response optimization.
- The closed-loop system effectively maintained temperature and gas concentrations at desired levels with low power consumption.
- The proposed technique significantly reduces time and cost in constructing ventilation system prototypes.

## Abstract

Underground small indoor gymnasiums (USIG) are important public places, it is vital to design and build a very economical and efficient ventilation system for effective closed-loop regulation of temperature and gases concentration at prescribed levels. In the article, the model-based prototype design, establishment and operation were proposed and applied to closed-loop control system of the underground small indoor gymnasiums’ ventilation system (USIGVS). First of all, the extended Multiphysics model was developed through feedback connecting the 3D Multiphysics model of air flow rate, temperature, O2 and CO2 concentration with a 0D proportional-integral-derivative (PID) controller via Neumann boundary condition, hence a close-loop USIGVS was constructed for feedback control of temperature and gases concentration in ping-pong USIG. Simultaneously, a cost function sufficiently representing the design requirement was formulated. Then global parameter sensitivity analysis (GPSA) was applied for sensitivity ranking of parameters including geometric parameters of USIGVS and tunable parameters of PID controller. The GPSA proved that sensitivity ordering of the cost function to each parameter was proportional gain (kp) > derivative gain (kd) > distance from left inlet to bottom (r) > distance from outlet pipe to bottom (d) > integrative gain (ki) > distance from upper inlet pipe to left (h), respectively, and the kp, kd and r was the parameter influencing the cost function the most. The optimal parameters determined by both GPSA and response optimization were kp = 3.17 m4 mol−1 s−1, kd = 1.49 m4 mol−1, r = 2.04 m, d = 3.12 m, ki = 0.37 m4 mol−1 s−2 and h = 3.85 m. Finally, the closed-loop USIGVS prototype with optimal parameters was designed and established through real-time simulation. The real-time operation confirmed that the temperature and gases concentrations were robust maintained at prescribed levels with desired dynamic response characteristics and lower power consumption, and the expected requirements were achieved for the design, establishment and operation of closed-loop USIGVS control system prototype.

•Close-loop USIGVS control system with the optimal parameters obtained.•Response optimization can maintain the temperature and gases concentrations at prescribed levels.•This technique can greatly save time and cost in construction of USIGVS prototype.

Close-loop USIGVS control system with the optimal parameters obtained.

Response optimization can maintain the temperature and gases concentrations at prescribed levels.

This technique can greatly save time and cost in construction of USIGVS prototype.