有室内热源自然与机械通风环境温度实验比较

Comparison of indoor temperature between natural and mechanical ventilation in a compartment with a heat source

为了研究在不同功率热源的情况下,自然通风和机械通风对房间内温度场的影响程度.对房间四壁和顶棚不同位置开口和不同尺寸,在自然通风情况下房间内温度场受到的影响进行了实验比较.结果说明,自然通风对流交换主要由热源附近空气受热后卷吸侧向窗口外部的冷空气进入产生,开天窗时才会有明显散热效果.对于墙壁侧向开口情况,出现空间内部上下层之间冷热分层明显,但散热效果不明显.实验还显示出机械通风比自然通风气流扰动强度要大很多.在实际工程设计中,采用顶窗和侧窗的兼备考虑,才有最适合的自然通风效果.

To study the effects of natural and mechanical ventilation on the indoor temperature under heat sources of different powers,experiments were carried out to compare the indoor temperature field with natural ventilation under different conditions,using various vent sizes and locations on the walls or ceiling.The results show that natural ventilation is mainly due to cool air from a side-window resulting from the entering of air rising near the heat source.Therefore,it is highly effective to heat dissipation with the vent opening being on the roof.When the vent is vertical,the layers of hot air and cool air stratify vertically;however,the effect of heat dissipation is not evident yet.Furthermore,it was found that the air perturbation is much stronger for mechanical ventilation than that for natural ventilation.It was suggested that the most efficient ventilation is with side-windows and skylights all in considering in the practical engineering.