Investigation of the Condensation Potential on Concrete Slab with Embedded In-Slab Ductwork

研究建筑室内表面的凝结势是非常重要的，因为湿气凝结会对建筑能源使用、建筑围护结构耐久性和与霉菌生长相关的居住者健康风险产生影响。板内风管内嵌混凝土板的表面温度受入风冷新风温度、流量、运行时间以及板内风管尺寸的影响。不幸的是，在各种实际环境条件下，板内管道系统的性能在文献中是不可用的。本研究项目的目标是描述在各种室内和室外设计和操作条件下，在一系列气候条件下，板内管道嵌入混凝土板表面的凝结势。为了实现这一目标，我们进行了一系列的实验室实验，测量混凝土板表面的温度和湿度，这些板内的嵌入式管道包裹着不同水平的保温材料。在本研究中，将考虑三种管道保温类型，即Tyvek， Reflectix, Bubble Wrap，并将其与无保温的板内管道（参考案例）进行比较，研究其相对性能。实验将使用BCIT卓越建筑科学中心的建筑围护结构测试设备（BETF）进行。在实验研究中，四块200毫米厚的矩形混凝土板，每一块都嵌入了一个板内管道，它们具有相同的配置，但包裹着不同级别的绝缘材料，将被放置在betf内。混凝土板的上下表面将暴露在由BETF空调系统提供的相同室内条件下，该室内条件将设置为室内设计条件（即21°C，30% RH）。外部新鲜空气进气口一侧的混凝土板边缘将暴露在室外气候条件下。混凝土板的其余边缘将被隔热，以尽量减少室内环境和板之间不希望的热量传递。在混凝土板的上下表面测量的湿度和温度将被用来评估备选方案的冷凝潜力

It is very important to investigate the condensation potential on building indoor surfaces since the moisturecondensation can have an impact on building energy uses, building envelope durability and occupants' healthrisks associated with mold growth. The surface temperature of the in-slab duct's embedding concrete slab canbe affected by the inflow cold fresh air's temperature, flow rate and the running period of time as well as thein-slab duct size. Unfortunately, the performance of in-slab duct systems in various realistic environmentalconditions is not available in literature. The objectives of this proposed research project is to characterize thecondensation potentials on the surface of the in-slab duct's embedding concrete slab under various indoor andoutdoor design and operating conditions for a range of climatic conditions. To achieve this objective, a seriesof lab experiments to measure the temperature and the humidity on the surface of concrete slab with theembedded in-slab ducts wrapped with different levels of insulation. In this study, three duct insulation typesnamely Tyvek, Reflectix, Bubble Wrap will be considered, and their relative performance in comparison withan in-slab duct with no insulation (reference case) will be investigated. The experiment will be conducted usingthe BCIT Building Science Centre of Excellence's Building Envelope Test Facility (BETF). In the experimentalstudy, four pieces of 200 mm thick rectangle shaped concrete slabs each of which embeds an in-slab ductcoming with the same configuration but wrapped with different levels of insulation will be placed inside theBETF. Both upper and bottom surfaces of the concrete slab will be exposed to the same indoor conditionsprovided by the air conditioning systems in BETF, which will be set at indoor design conditions (i.e. 21°C,30% RH). The edge of the concrete slab at the outside fresh air intake side will be exposed to outdoor climaticconditions. The rest of the edges of the concrete slab will be insulated in order to minimize the undesired heattransfer between the indoor environment and the slab. The measured humidity and temperature at upper andbottom surfaces of the concrete slab will be used to evaluate the condensation potential of the alternative