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

研究建筑物室内表面的冷凝潜力是非常重要的，因为湿度凝结会影响建筑物的能源使用、建筑围护结构的耐久性以及与霉菌生长相关的居住者的健康风险。板内埋设混凝土板风道的表面温度受进口冷新风的温度、流量、运行时间以及板内风道尺寸的影响。遗憾的是，板内风管系统在各种实际环境条件下的性能在文献中是不存在的。该研究项目的目的是在不同的室内和室外设计和运行条件下，在各种气候条件下，表征板内埋设混凝土板的板内管道表面的冷凝潜力。为了实现这一目标，进行了一系列的实验室实验，测量了埋设不同保温等级的板内管道的混凝土板表面的温度和湿度。在这项研究中，将考虑三种风管保温形式，即特维克、反射、气泡包裹，并将其与无隔热的板内风管(参考情况)进行比较。该实验将使用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将被放置在BETF内，每块板内嵌有一条相同配置但包裹着不同绝缘水平的板内管道。混凝土楼板的上表面和下表面将暴露在由BETF空调系统提供的相同的室内条件下，这些条件将设置在室内设计条件(即21°C，30%相对湿度)。室外新风进风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，以最大限度地减少室内环境和板之间不需要的热量传递。混凝土板上下表面的湿度和温度的测量将被用来评估替代方案的凝结潜力。

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