Experimental evaluation for the dynamic insulation applied to window frame

An efficient thermal insulation of glazing or window frame is important because poor insulating performance usually cause the largest heat loss on any buildings. As one of the methods decreasing heat loss of buildings, we proposed a dynamic insulation system applied to window frame, and its energy saving performance and applicability for buliding had been confirmed using numerical simulation in previous study [1].
The aim of this study is to evaluate the thermal insulation efficiency of the proposed system by field test using experimental model houses among which we mainly focus on the dynamic insulation applied to window frame. First, the prototype of proposed system is designed to ventilate through the dynamic insulation in a window frame based on the fixed window which uses argon gas injected triple glazing. Then, we verify its thermal insulation efficiency in transient state, we constructed two experimental model houses located in Sapporo, Japan. The one of the house is installed a normal window frame with argon gas injected triple glazing coated Low-E film and the other one is installed in the proposed window frame. Finally, we evaluated the U-value of the proposed window frame by changing the ventilation rates through the dynamic insulation, after measuring the heat loss differences and the effective air leakage area to compare the airtightness and thermal insulation efficiency of two experimental model houses.
Although it could not measured the same U-value on the proposed window frame compare with the chamber test and field test unfortunately, the thermal insulation efficiency is increased by increasing ventilation rates through the dynamic insulation. The field test results show that the thermal insulation efficiency is increased approximately 89 % (U-value :1.80 W/(m2·K) →0.20 W/(m2·K)) at the experimental model house installed in the proposed window frame by increasing ventilation rates (0.00 m3/h → 30.00 m3/h). The ventilation volume led through the DI frame by pressure differences of inner/outer space heightens the thermal insulation performance. Therefore, DI window frame is an effective means of increasing the thermal insulation efficiency in any building.