Extract

Passive House, promoted mostly in Germany, requires a high level of airtightness and high-quality construction, which can slow down the building process and so lead to difficulty in popularization. On the contrary, prefabricated building systems provide installation efficiency and protection of the site environment. By combining Passive House with prefabricated structures, a building project may not only achieve the standards for Passive House, but also be constructed within a short time. The two primary problems in designing and building prefabricated Passive Houses are cracks caused by the on-site assembly of components, and thermal bridges due to the steel structure. Taking a building in Jinan, China as a case study, this paper introduces a prefabricated, thermal bridge-free insulation system. The sandwich-shaped exterior wall system has four layers: a 100 mm PC inner wallboard, two 75 mm staggered high-density polyurethane insulation layers, and a 50 mm PC outer wallboard. By improving the structure of the key nodes, namely the slab joints of the exterior wallboards, foundation, roofs, and exterior window openings, the compound heat-transfer coefficient of this building envelope is 0.146 W/(m2`k), while the air change rate under 50 Pa differential pressure is 0.56/h.

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