这项研究是正在进行的一项研究的一部分，旨在开发一个数学模型，用于预测冬季阁楼内的热湿传递过程。这样一个模型将为生成阁楼通风指南提供合理的基础，以防止屋顶覆盖层下侧形成冷凝（或结霜）。在一个高隔间的环境室内安装了一个带有倾斜屋顶/通风阁楼的小型试验室。试验室及其阁楼广泛安装了测量热湿传递的仪器。随后，试验室暴露在一系列稳定且日间的室外气候条件下。 在试验室内模拟了住宅的典型条件。在阁楼关闭的情况下进行了几次测试（即没有通风）。其他测试是在阁楼上进行的，其通风速率相当于住宅的拱腹通风。一些测试是在室内空气通过天花板结构进入阁楼的情况下进行的。一个意外的发现是，在任何测试条件下，倾斜屋顶下侧的阁楼都没有发生冷凝。建立了一个数学模型，包括阁楼木材表面的水蒸气吸附。 该模型精确预测了稳态和动态室外循环试验的阁楼露点温度。该模型显示，含水率为12.5%（按重量计）的阁楼木材表面会吸附水蒸气，并将木材表面露点温度保持在屋顶覆盖层温度以下，从而防止冷凝。数学模型预测，阁楼中的木材表面将继续吸附水蒸气，直到它们与阁楼空气达到水分平衡，然后发生冷凝。引文:ASHRAE Transactions，1984年，第90卷，pt。 密苏里州堪萨斯城2A号

This study is part of ongoing research to develop a mathematical model for predicting heat-and moisture-transfer processes in attics during the winter. Such a model would provide a rational basis for the generation of attic ventilation guidelines for preventing condensation (or frost) formation at the underside of roof sheathing.A small test house having a pitched roof/ventilated attic was installed in a high-bay environmental chamber. The test house and its attic were extensively instrumented for measuring heat and moisture transfer. The test house was subsequently exposed to a series of steady and diurnal outdoor climatic conditions. Representative conditions of a residence were simulated within the test house.Several tests were conducted with the attic closed off (i.e., no ventilation was provided). Other tests were conducted with the attic ventilated at a rate equivalent to soffit venting for a residence. Some tests were conducted with house air induced to exfiltrate through the ceiling construction into the attic. An unexpected finding was that attic condensation at the underside of the sloping roof did not occur under any of the test conditions.A mathematical model was developed that included the adsorption of water vapor at wood surfaces in the attic. This model closely predicted the attic dew-point temperatures for both the steady and dynamic outdoor cycle tests. The model showed that wood surfaces of the attic at a moisture content of 12.5 percent (by weight) adsorbed water vapor and maintained the wood surface dew-point temperature below the roof sheathing temperature, thereby preventing condensation. The mathematical model predicted that the wood surfaces in the attic would continue to adsorb water vapor until they attained moisture equilibrium with the attic air, after which condensation would occur.