Research on Advanced Technologies for Housing: Eave Icing of Residential Buildings

本课题是一项关于我国低层住宅楼屋檐结冰的多学科研究项目。具体来说，该项目的目标是发展对屋檐结冰的基本理解，而目标是开发一个分析模型，预测一个和两个家庭住宅单元屋檐上冰坝的大小。不幸的是，屋檐冰坝的形成在较冷的气候中很常见。当冰坝变大时，典型的结果是内部表面（墙和天花板）变湿。在美国，屋檐结冰可以说是最常见和最昂贵的与冰雪有关的损失，对于一个和两个家庭的住宅单位来说。就其性质而言，待开发的模型将同时处理屋檐上坡处融水的产生以及屋檐区域融水的凝固。这种分析模型的发展将使工程师和建造者能够以知识和定量的方式处理问题。也就是说，对于给定的屋顶（即固定的屋脊与屋檐的距离、屋顶坡度、屋顶r值等），分析模型将允许计算导致冰坝形成的冰点以下天数和屋顶雪深的组合。相反，对于给定的冬季环境和屋顶，该模型允许人们计算最小屋檐悬垂距离或连续金属闪光的宽度，以避免室内潮湿。该模型将通过在全尺寸建筑物上进行简单的现场实验观察，并尽可能通过比较和分析保险公司以往冬季的损失信息来验证和基准。该项目的目标与推进住房技术伙伴关系（PATH）的目标一致。也就是说，如果使用得当，结果将导致减少财产破坏的风险，提高耐久性，减少维修费用，从长远来看，减少每月的住房费用。这个多学科的项目团队由伦斯勒大学的土木工程师Michael O'Rourke教授领导，他是积雪对建筑结构影响领域的专家。共同负责人是伦斯勒机械工程系的理查德·史密斯教授，他是传热和凝固方面的专家。为了确保这项新技术的适当转让和使用，一个由全国住宅建筑商协会和州立农场建筑技术研究实验室代表组成的项目咨询小组已经成立。

The proposed work is a multi-disciplinary research project on eave icing of the nation's low-rise residential building stock. Specifically the goal of the project is to develop a fundamental understanding of eave icing while the objective is development of an analytical model which predicts the size of a ice dam at the eave of one and two family dwelling units. The formation of eave ice dams is, unfortunately, a common occurrence in colder climates. When ice dams become large, wetting of interior surfaces (walls and ceilings) is the typical result. Eave icing is arguably the most common and costly ice and snow related loss for one and two family dwelling units in the United States. By its nature, the model to be developed will address both the generation of meltwater upslope of the eave, as well as solidification of the meltwater at the eave area. This development of an analytical model will allow engineers and builders to deal knowledgeably and quantitatively with the problem. That is, for a given roof (i.e., fixed ridge to eave distance, roof slop, roof R-value, etc) the analytical model would allow one to calculate the combination of below freezing days and roof snow deph which result in ice dam formation. Conversely, for a given winter environment and roof, the model allows one to calculate the minimum eave overhang distance or width of continuous metal flashing required to avoid interior wetting. The model will be verified and benchmarked through simple in-situ experimental observations on full scale buildings and to the extent possible by comparison to and analysis of insurance company loss information from prior winters. The project's objectives are compatible with those of the Partnership for Advancing Technology in Housing (PATH). That is, the results, when properly used, will lead to a reduced risk of property destruction, improved durability, reduced maintenance costs and in the long run reduced monthly cost of housing.The multi-disciplinary project team is lead by a civil engineer, Professor Michael O'Rourke of Rensselaer, who is an expert in the area of snow effects on building structures. The Co-PI is Professor Richard Smith, of Rensselaer's Mechancial Engineering Department, who is an expert on heat transfer and solidification. In order to ensure appropriate transfer and use of this new technology, a project advisory group consisting of representation from the National Association of Home Builders and State Farm's Building Technology Research Lab has been established.