| Research Abstract |
This study aims to arrange the technical guidelines for mechanical central ventilation systems suitable for air-tightened houses. In this paper, we called 2kinds of mechanical ventilation systems the duct system and the forced exhaust system respectively. With the duct system, supply fresh outdoor air is carried to each room with supply duct and forced fan, besides exhaust air from each room is flowed to a corridor through under-cut opening of door and is sucked to the mechanical ventilation unit. With forced exhaust system, exhaust air is sucked from a bathroom or a wash room and the pressure difference makes outdoor fresh air come in the room through a inlet installed on extemal wall.
Results of full scale experiments to clarify the relations among the air-tightness of apartment houses, weather conditions, infiltration air volume and ventilation rate, sugested that higher technical level for air-tightness is required in order to work the forced exhaust system perfectly. The duct syste
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m is recommended for any air-tightened houses.
Air flow resistance coefficients of under-cut opening of door, fresh air inlet installed on external wall, ventilation grille, door grille of bathroom, fusuma (Japanese traditional fitting) and so on, through which air flow path is made with mechanical ventilation systems, are measured and data base of input for simulation program analyzing air flow conditions with mechanical central ventilation systems are prepared.
Simulation program analyzing air flow conditions with mechanical central ventilation systems are developed and verified. Various factors related with the mechanical central ventilation systems are checked by this simulation program. For example, pressure difference induced by temperature difference induce indoor air to go out through the openings located at the first floor level and outdoor air to flow in through the openings located at ground level in winter. Such air flow condition is not proper. Corrected height of opening at the first level improve air flow pattem. Forced supply and exhaust ventilation systems for kitchen ventilation and bathroom ventilation are recognized not to disturb the air flow path. Many technical data are summarized to the technical guidelines. Less
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