Shinsuke Kato, Sihwan Lee
Bibliographic info:
32nd AIVC Conference " Towards Optimal Airtightness Performance", Brussels, Belgium, 12-13 October 2011

It is essential to reduce the inordinate amount of energy used for climate control in buildings. To reduce heat loss in residential buildings, it is necessary to insulate building envelopes more airtight. Many air tightness and insulation methods have been proposed and successfully applied to the building envelope, including areas such as walls, windows and the others. However, if it concentrates only air tightness and insulation to save energy consumption in the buildings, that’ll make a problem to maintain indoor air quality within acceptable levels, such as sick building syndrome.
To solve this problem, this paper proposed a new dynamic insulation system applied to the glazing and frame of the windows. Dynamic insulation refers to the use of porous insulation material through which ventilation air enters a building, thereby reducing the conductive heat loss through the material to very low level. Moreover, the proposed system is composed of three parts by installing two additional parts to control indoor/outdoor pressure difference and to reduce ventilation loads: a double pane airflow window system with window frame made of a porous material, a mechanical ventilation system, and a heat-recovery heat pump system.
The aim of this paper is to evaluate the thermal insulation efficiency and probability of moisture condensation in the proposed glazing system in order to confirm its feasibility and applicability. First, a double pane airflow window system was designed to ventilate through the window frame and the air space of a double pane window. Then, to verify its thermal insulation efficiency, the temperature distribution of the window system was evaluated using computer fluid dynamics with different coupled conditions, such as the indoor/outdoor pressure difference and outdoor temperature, after confirming calculation accuracy using glazing model. In addition, to verify the probability of moisture condensation, the relative humidity in the window system was calculated based on the various conditions.
The calculated results show the thermal load was proportional to the outdoor temperature and inversely proportional to the indoor/outdoor pressure difference. Moisture condensation depends on the outdoor temperature and humidity ratio and it does not occurred when outdoor temperature is more than 6.0 ºC in the proposed system. Therefore, the proposed system is technically feasible to reduce the home energy consumption by installed residential buildings.