Thermal comfort assessment in offices employing the Fiala model with impinging jet ventilation parameter optimization

This paper analyzes the thermal comfort conditions of small offices with IJV systems based on the SST (shear-stress transport) k-ω turbulence model. It compares the thermal comfort and energy-consumption performances of IJV and MV systems, focusing on the impacts of supply-air temperature and velocity, with radiative heat transfer simulations conducted using the S2S (Surface-to-Surface) radiation model. The Fiala Thermoregulation and Equivalent Homogeneous Temperature (EHT) models are employed to evaluate human thermal comfort. Results show that under identical supply conditions, the IJV system enhances thermal comfort. At a supply velocity of 1.75 m/s and 25°C, only 8.37 % of people are dissatisfied, a 10.86 % decrease from the MV system. The IJV system is also more energy-efficient, reducing consumption by about 5.35 % under similar thermal comfort conditions. It disperses the thermal plume and maintains a uniform temperature around the body, offering some protection against the impact of the nearby air supply inlet. At 1.75 m/s, a supply temperature of 24°C is optimal for comfort. At 25°C, increasing the velocity improves comfort. At 2.5 m/s, the Fiala Predicted Percentage Dissatisfied and Fiala Dynamic Thermal Sensation are decreased by about 27.25 % and 32 %, respectively, compared to 1 m/s, significantly enhancing thermal comfort. © 2025 Elsevier Ltd.