Study on Multi-Field Coupling Mechanism and Energy Efficiency Optimization of Air Supply Parameters in University Classrooms under Severe Cold Climate

A multi-field coupled numerical model based on CFD-UDF secondary development technology was established to solve high energy consumption of winter heating in university classrooms in severe cold regions. The study conducted synergistic analysis of indoor temperature fields, flow fields, CO 2 concentration fields, diffusion and migration of virus-laden droplet aerosols, and total heating energy consumption under a side-supply and bottom-exhaust ventilation mode at 0.50 m/s, 0.75 m/s, and 1.00 m/s air supply velocities. Based on a multi-objective optimization framework, the study aimed to identify air supply parameters that achieved the best energy-saving effect while ensuring indoor air quality and health safety. The results show that when the air supply velocity is 0.75 m/s, indoor temperature ranges from 22.1°C to 22.8°C, the average velocity near the human body area is 0.13 m/s, and CO 2 concentration is between 924 and 956 ppm. Compared to the air supply velocity of 1.00 m/s, droplet aerosols residence time is reduced by 32% and heating energy consumption is lowered by 202 kWh/m 2 ·at 0.75 m/s air supply velocity.