UFAD（地板下空气分配）系统的使用正在迅速增加，据报道UFAD的优点包括节能和改善室内空气质量。目前，很少有出版物记录了UFAD占用建筑物的通风效率和室内环境质量的测量结果。在这项实地对比研究中，我们测量了位于魁北克省蒙特勒阿尔市的两栋建筑中不同通风系统（地板下空气分配和混合）的热环境的几个方面。结果以热分层、预测热舒适指数（VATD、风速极限和PMV/PPD）和室内空气品质指数（CO2水平和分层）的形式呈现。这项研究的目的是确定UFAD是否在不影响热舒适性的情况下，在实际应用中，与典型的头顶空气分配相比，提高了通风效率。 该研究发现，在运行条件下，UFAD几乎没有分层，它作为一个混合系统运行，因此，与参考混合系统相比，占用区域的通风效率没有改善。此外，就VATD、风速和PMV/PPD而言，预测的热舒适性与混合通风获得的热舒适性相似，并且在ASHRAE 55-2010设定的可接受限值范围内。引文:ASHRAE论文CD:2014 ASHRAE年会，华盛顿州西雅图

The use of UFAD (Underfloor Air Distribution) systems is increasing rapidly and reported advantages of UFAD include energy savings and improved indoor air quality. At present few publications documenting measurements of ventilation effectiveness and indoor environment quality in occupied buildings with UFAD have been identified. In this field comparison study we measured several aspects of the thermal environment in two buildings with different ventilation systems (under-floor air distribution and mixing) located in Montréal (Québec). The results are presented in terms of thermal stratification, predicted thermal comfort indices (VATD, limit to air speed and PMV/PPD), and IAQ index (CO2level and stratification). The aim of the study was to determine whether UFAD in practice results in improved ventilation effectiveness compared to typical overhead air distribution without affecting the thermal comfort. The study found that there was little stratification for UFAD under operating conditions and it performed as a mixing system, thus no improvement in ventilation effectiveness was identified in the occupied zone, in comparison to the reference mixing system. In addition the predicted thermal comfort in terms of VATD, air speed and PMV/PPD was similar to those obtained for mixing ventilation and was within the acceptable limits set by ASHRAE 55-2010.