窓部におけるダイナミックインシュレーション技術の適用: 第1報——熱箱及び実測による省エネ性能検証

摘要

建物の省エネ化を実現する有効的な方策として外皮表面において温度勾配を零にするダイナミックインシュレーション（DI：Dynamic Insulation)技術に着目した。本技術は寒冷地のカナダや北欧に研究例のある技術であり、近年ではイギリスにおいて技術適用した断熱改修例がある。その適用例は大半が壁体であり、熱損失の大きい窓部に適用した例は少ない。そこで本研究は日本における寒冷地を代表し、札幌において、その窓部にDI技術を適用し、断熱性能、結露発生リスクの評価、及び熱回収率•昇温率を熱箱試験と実証試験により検証した。その結果、適用した窓部の断熱性能の向上と一般通気口への優位性を確認し、結露発生条件を明示した。%Establishment of zero-energy buildings (ZEBs) and methods for reducing energy consumption and effective use of energy, such as net zero energy, are typically required for the realization of sustainable buildings, and realization of ZEBs is an urgent worldwide demand. Toward meeting this demand, we studied a dynamic insulation (DI) system, which uses ineluctable ventilation airflow effectively. Application of the DI system is distinct from the conventional building practices in the U.K. Majority of the previous practices applied the DI system to wall parts, but not to opening parts such as windows and sashes, which have poor thermal insulation performance. Therefore, we created prototypes of window with the DI system, called the DI window. The DI window consists of three parts: an outside window, air layer, and inside window. We evaluated the thermal insulation performance of the DI window, the risk of condensation on the inside sash surface, and the heat recovery rate and the rate of temperature increase between the inlet and outlet of the window. Further, we performed a heat box test qualitatively and a field test for practical application. As a result of the heat box test, we verified the effect of the DI window on energy-saving rate with increasing ventilation airflow and the positive effect on thermal insulation performance after installing a blind in the air layer. The results of the field test showed improvement of the thermal insulation performance under the condition of a real residential house installed with the DI system. Notably, the DI window with a blind in the air layer demonstrated the best thermal insulation performance in majority of the cases; however, it increased the risk of condensation on the inside sash surface. Therefore, we calculated the tolerance dew point temperature of the inside surface of the window frame for a certain Technical Advisory Committee temperature (-9.4[℃]) in the real condition and the tolerance relative humidity of the indoors of the residential house.