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

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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