Underfloor air distribution (UFAD) systems are known to provide thermal comfort and good indoor air quality (IAQ) at relatively low energy cost. The aim of this paper is to develop an analytical model to predict the vertical CO₂ distributions inside contaminated thermal plumes and in the surrounding air in UFAD spaces. The 2D model is based on thermal plume and turbulent fountain theory and it accounts for CO₂ convective transport as well as vertical and lateral diffusion. The proposed space model consists of four horizontal layers delimited by three critical heights: the air density interface, the supply jet throw height and the plume terminal height. The model predictions of lumped layer CO₂ concentrations compared well with the results produced by computational fluid dynamics (CFD) simulations for different ventilation rates and heat loads. The analytical model can be put into practice to give recommendations on UFAD preliminary design and acceptable IAQ.

已知地板下空气分配（UFAD）系统以相对较低的能源成本提供热舒适性和良好的室内空气质量（IAQ）。本文的目的是建立一个分析模型，以预测UFAD空间中被污染的热羽内部和周围空气中的垂直CO ₂分布。二维模型基于热羽流和湍流喷泉理论，它考虑了CO ₂对流传输以及垂直和横向扩散。所提出的空间模型由四个水平层组成，这些水平层由三个临界高度界定：空气密度界面，供气喷射高度和烟羽末端高度。集总层CO ₂的模型预测与不同通风速率和热负荷的计算流体力学（CFD）模拟所产生的结果相比，该浓度很好。可以将分析模型付诸实践，以提供有关UFAD初步设计和可接受的IAQ的建议。