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

建筑物室内表面结露对建筑物的能源利用、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都有影响，因此研究建筑物室内表面结露的可能性非常重要。板内风管预埋混凝土板的表面温度受来流冷新风的温度、流量、运行时间以及板内风管尺寸的影响。不幸的是，在各种现实环境条件下的板内风管系统的性能在文献中不可用。本研究项目的目标是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，表征板内管道的嵌入混凝土板表面上的凝结潜力。为了实现这一目标，进行了一系列的实验室实验，测量温度和湿度的混凝土板表面与嵌入板内管道包裹不同程度的绝缘。在本研究中，将考虑三种管道绝缘类型，即Tyvek、Reflectix、Bubble Wrap，并将研究它们与无绝缘的板内管道（参考案例）相比的相对性能。该实验将使用BCIT建筑科学卓越中心的建筑围护结构测试设施（BETF）进行。在实验研究中，四块200 mm厚的矩形混凝土板，每个板嵌入一个板内管道，具有相同的配置，但包裹有不同程度的绝缘将被放置在BETF内。混凝土板的上下表面将暴露于BETF空调系统提供的相同室内条件下，该条件将设置为室内设计条件（即21° C，30%RH）。外部新鲜空气入口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的不期望的热传递。在混凝土板的上、下表面测得的湿度和温度将用于评估替代方案的冷凝潜力

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